JP2010096036A - Imbalance correction method of turbo charger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an imbalance correction method of a turbo charger capable of eliminating a step which is apt to cause an error, such as a step in which imbalance calculation is carried out, or a step in which balance adjustment by machining or the like is carried out, and of thereby improving the precision of imbalance correction. <P>SOLUTION: The method for correcting the imbalance of a turbo charger is used for the turbo charger 1 which includes a rotatable body 2 rotatably supported around a prescribed rotation axis (turbo rotation axis C1), and supercharges by means of the rotation of the rotatable body 2. The rotatable body 2 is provided with a space (material holding space 31) having a rotational shape centered on the turbo rotation axis C1. With silver nanopaste 40 put in the material holding space 31, a rotating step to rotate the rotatable body 2 at a prescribed speed or faster to flow and unevenly distribute the silver nanopaste 40 to a position where the imbalance of the rotatable body 2 is equalized, and a heating step to heat the silver nanopaste 40 to harden the silver nanopaste 40 and fix it to the wall are carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a turbocharger unbalance correction method used to correct an unbalance of a rotating body of a turbocharger, for example, for a turbocharger mounted on an engine such as an automobile engine.

  For example, a turbocharger mounted on an engine such as an automobile engine has a rotating body that rotates by using exhaust from the engine as a power source, and the rotation of the rotating body (specifically, rotation of a compressor wheel included in the rotating body). Compresses and supercharges the intake air supplied to the engine. By supercharging with the turbocharger, the engine output can be improved. The turbocharger rotating body rotates at a very high speed during supercharging.

  In such a turbocharger having a rotating body that rotates at a high speed, if the unbalance existing in the rotating body is large, vibration due to the rotation of the rotating body becomes excessive, and vibrations of a portion that supports the rotating body, etc. There may be a problem such as noise. For this reason, in the turbocharger, the balance of the rotating body is very important. Therefore, for the turbocharger, the imbalance of the rotating body is corrected during the manufacturing process (see, for example, Patent Document 1). Patent Document 1 discloses a technique for correcting an unbalanced state in a short time without disassembling a turbocharger in a configuration in which a rotational force is applied to a rotating body by a rotating electrical machine.

  Conventionally, correction of unbalance of a turbocharger is generally performed as follows. When correcting the unbalance of the turbocharger, air corresponding to the exhaust from the engine is used, and the rotating body is rotated at a predetermined rotational speed. With the rotating body rotating, vibration acceleration is detected by the acceleration pickup, and the rotation angle (phase) of the rotating body is detected by the phase detector. Based on the detected vibration acceleration and rotation angle (phase), the amount and phase of the unbalance of the rotating body are calculated. Based on the calculated unbalance amount and phase, the balance of the rotating body is adjusted (imbalance correction). The balance is adjusted by cutting and removing a predetermined portion corresponding to the unbalance in the rotating body by machining or the like.

Such a conventional imbalance correction method has the following problems. That is, in the conventional method, as described above, after the unbalance is calculated based on the detected values of vibration acceleration and phase, the balance is adjusted by cutting based on the calculated values. For this reason, in the conventional method, a calculation error in unbalance calculation and a processing error in balance adjustment occur. As a result, the number of times of unbalance correction is increased, and the imbalance correction accuracy is limited. In other words, in the conventional method, errors occurring in each process of the process where the unbalance is calculated and the process where the balance is adjusted accumulate, so it is difficult to improve the unbalance correction accuracy. In the turbocharger, in order to cope with further noise reduction in the future, it is necessary to improve the imbalance correction accuracy.
JP 2008-8219 A

  The present invention has been made in view of the above problems, and the problems to be solved include a process in which an unbalance is calculated, a process in which balance is adjusted by cutting, and the like. An object of the present invention is to provide a turbocharger unbalance correction method capable of omitting a process in which an error is likely to occur and improving imbalance correction accuracy.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, according to claim 1, there is provided a turbocharger unbalance correction method comprising a rotating body that is rotatably supported around a predetermined rotation axis, and performing supercharging by rotation of the rotating body, wherein the rotation A paste-like or liquid fluid material that is provided in a body with a space having a rotational shape centered on the rotational axis, is cured by being heated, and is fixed to a wall surface that forms the space. A rotating step of rotating the rotating body at a predetermined number of revolutions or more in order to cause the fluid material to flow and be unevenly distributed in the space to a position that cancels the unbalance of the rotating body in the space. A heating step of heating the fluid material in order to cure and fix the fluid material in a state unevenly distributed in the space by the rotation step to the wall surface; Is performed.

  According to a second aspect of the present invention, the rotating body is provided with an inlet for putting the fluid material into the space, and the rotating body in which the fluid material is not placed in the space is provided in a predetermined manner before the rotating step. A measurement step of measuring the amount of unbalance of the rotating body by detecting vibration associated with the rotation of the rotating body in a state of being rotated at a rotational speed; and the unbalance of the rotating body measured by the measuring step And an injection step of putting an amount of the fluid material corresponding to the amount of the fluid material into the space from the injection port.

  According to a third aspect of the present invention, in the turbocharger imbalance correction method according to the first or second aspect, the rotating body includes a shaft portion whose axial direction is the direction of the rotating shaft, and an axial direction of the shaft portion. A turbine wheel portion provided on one end side of the shaft for obtaining rotational power of the rotating body, and an impeller fixed to a shaft member forming the shaft portion to be provided on the other end side in the axial direction of the shaft portion. A compressor wheel portion for compressing intake air when supercharging, and the compressor wheel portion includes a fixing member for fixing the impeller to the shaft member, and the space is used as the fixing member. It is provided.

  According to a fourth aspect of the present invention, in the turbocharger imbalance correcting method according to the first or second aspect, the rotating body forms a shaft portion whose axial direction is the direction of the rotating shaft, and the shaft portion. A turbine wheel part for obtaining rotational power of the rotating body provided on one end side in the axial direction of the shaft part by fixing a wheel member to the shaft member, and provided on the other end side in the axial direction of the shaft part And a compressor wheel portion for compressing intake air at the time of supercharging, and the space is provided between the shaft member and the wheel member.

  According to a fifth aspect of the present invention, in the turbocharger imbalance correcting method according to the first or second aspect, the rotating body forms a shaft portion whose axial direction is the direction of the rotating shaft, and the shaft portion. By fixing the wheel member to the shaft member, the turbine wheel portion provided on one end side in the axial direction of the shaft portion for obtaining the rotational power of the rotating body, and the impeller being fixed to the shaft member, A compressor wheel portion that is provided on the other end side in the axial direction of the shaft portion and compresses intake air during supercharging, and the compressor wheel portion includes a fixing member for fixing the impeller to the shaft member. The space is provided between the fixing member and the shaft member and the wheel member.

  The turbocharger imbalance correction method according to claim 4 or claim 5, wherein the fluid material in the space provided between the shaft member and the wheel member in the heating step is provided. Is heated by using a high-temperature gas having a temperature that is at least high enough to cure the fluid material as the air to be supplied to the turbine wheel portion in order to give the rotational power of the rotating body.

  In the seventh aspect, in the turbocharger imbalance correction method according to any one of the fourth to sixth aspects, the state in which the wheel member is fixed to the shaft member is any of the shaft member and the wheel member. A fitting recess provided on one side and opening to one side in the direction of the rotation shaft, and a fitting protrusion provided on the other side of the shaft member and the wheel member and projecting to the other side in the direction of the rotation shaft And the bottom surface and the inner peripheral surface of the fitting recess and the tip surface of the fitting protrusion are used as the wall surface forming the space provided between the shaft member and the wheel member. Is.

  According to an eighth aspect of the present invention, in the turbocharger imbalance correcting method according to the seventh aspect, the fitting between the fitting recess and the fitting protrusion is press-fitting the fitting protrusion into the fitting recess. A gap communicating with the space is formed between the fitting protrusion and the inner peripheral surface of the fitting recess on the leading end side in the protruding direction of the fitting protrusion. The reduced diameter part which forms is provided.

  In a ninth aspect of the present invention, in the turbocharger imbalance correcting method according to the seventh or eighth aspect, at least the fitting is selected among the wall surfaces forming the space provided between the shaft member and the wheel member. The surface roughness of the bottom surface of the joint recess and the front end surface of the fitting projection is made relatively large with respect to the other portions.

  In Claim 10, In the turbocharger unbalance correction method according to any one of Claims 7 to 9, at least one of the inner peripheral surface of the fitting recess and the outer peripheral surface of the fitting protrusion. Further, as the rotating body rotates in the rotating step, the fluid material in the space provided between the shaft member and the wheel member is used as the inner periphery of the fitting recess in the direction of the rotating shaft. A spiral groove is formed that leads in the direction toward the back side of the mating surface portion between the surface and the outer peripheral surface of the fitting protrusion.

As effects of the present invention, the following effects can be obtained.
That is, according to the present invention, it is possible to omit an error-prone process such as a process in which unbalance is calculated and a process in which balance is adjusted by cutting or the like. Improvements can be made.

  The present invention provides an unbalanced turbocharger by providing a space in a rotating body of a turbocharger and holding a paste-like or liquid fluid material having a predetermined property as a material for correcting unbalance in the space. This is a correction.

  Specifically, the property of the fluid material held in the space provided in the rotating body is that it is cured by being heated and is fixed to the wall surface forming the space. Then, with the fluid material in the space of the rotator, the rotator is rotated at a predetermined number of revolutions, so that the fluid material in the space phenomenonally cancels the unbalance of the rotator. It will be in the state which flowed to the position and was unevenly distributed (the state which was balanced about the rotary body). In such a state, when the fluid material is heated, the fluid material is cured in a state of offsetting the unbalance, and is fixed to the rotating body through the wall surface forming the space, that is, the unbalance is corrected for the rotating body. The obtained state is obtained.

  As described above, the present invention puts a fluid material having a predetermined property in a space provided in a rotating body, and heats the fluid material to a predetermined temperature or more in a state where the rotating body is rotated at a predetermined rotation speed. Thus, it is intended to automatically correct the unbalance of the rotating body with high accuracy without performing a cutting process for adjusting the balance (correcting the unbalance). Embodiments of the present invention will be described below.

  A first embodiment of the present invention will be described. In the present embodiment, the configuration of the turbocharger 1 that is the target of unbalance correction will be described. As shown in FIG. 1, a turbocharger 1 of the present embodiment has a rotating body 2 supported so as to be rotatable around a predetermined rotating shaft (hereinafter referred to as “turbo rotating shaft”) C1, and this rotating body. Supercharge by rotating 2.

  The rotating body 2 is rotatably supported by a housing 3 that constitutes the turbocharger 1. The housing 3 is formed in a substantially cylindrical shape as a whole, and has a space portion penetrating in the central axis direction (cylindrical axis direction) (opening on both sides in the central axis direction) in the central axis portion (cylindrical axis portion). The rotating body 2 is rotatably supported in the space portion of the housing 3 in a state where the rotating body 2 passes therethrough.

  The rotating body 2 includes a shaft portion 21, a turbine wheel portion 22, and a compressor wheel portion 23. The shaft portion 21 is an axial portion whose axial direction is the direction of the turbo rotation axis C1 (hereinafter referred to as “rotation axis direction”). The turbine wheel portion 22 is a portion that is provided on one end side in the axial direction of the shaft portion 21 (on the right side in FIG. 1) to obtain the rotational power of the rotating body 2. The compressor wheel portion 23 is a portion that is provided on the other end side (left side in FIG. 1) of the shaft portion 21 in the axial direction and compresses intake air when supercharging by the turbocharger 1.

  In the present embodiment, the turbine wheel part 22 is a part formed integrally with the shaft part 21. However, the turbine wheel portion 22 may be configured by fixing a member separate from the shaft portion 21 to the shaft portion 21.

  The compressor wheel portion 23 is provided by fixing an impeller 26 to a turbine shaft 25 as a shaft member that forms the shaft portion 21. The impeller 26 is fixed to the turbine shaft 25 by using the nut body 30. That is, the compressor wheel portion 23 has a nut body 30 for fixing the impeller 26 to the turbine shaft 25. The turbine wheel portion 22 and the compressor wheel portion 23 protrude outward from the housing 3 in the direction of the rotation axis, and are positioned outside the housing 3.

  The rotating body 2 is rotatably supported by the housing 3 using a radial bearing 4 and a thrust bearing 5. The radial bearing 4 is fixed or rotatably supported by the housing 3 so that the center of rotation coincides with the turbo rotation axis C1. The radial bearing 4 is fixed to the housing 3 by press-fitting into the housing 3, for example. In the present embodiment, the radial bearing 4 is provided at two positions with respect to the shaft portion 21 while being spaced apart from each other by a predetermined distance in the direction of the rotation axis.

  The thrust bearing 5 supports the rotating body 2 via the collar 6. In the rotating body 2, the shaft portion 21 (of the turbine shaft 25) on the compressor wheel portion 23 side (left side in FIG. 1) has a shaft shape that is relatively narrower than other portions via a step surface 25a. A reduced diameter portion 25b which is a portion is formed. The impeller 26 constituting the compressor wheel portion 23 is supported by the turbine shaft 25 in a state where the reduced diameter portion 25b is passed through.

  The collar 6 is provided in a state of being sandwiched between an end surface on one side (right side in FIG. 1) of the impeller 26 and a step surface 25 a of the turbine shaft 25. That is, the impeller 26 is fixed by the nut body 30 with the collar 6 interposed between the impeller 26 and the stepped surface 25 a of the turbine shaft 25. Therefore, with respect to the fastening force by the nut body 30, the step surface 25 a becomes a receiving surface through the impeller 26 and the collar 6. Thus, the impeller 26 is positioned with respect to the turbine shaft 25 by being sandwiched between the nut body 30 and the step surface 25a via the collar 6.

  The collar 6 has an engaging portion 6 a that forms a contact surface that contacts the thrust bearing 5 from both sides in the rotation axis direction. Therefore, the engaging portion 6a has a shape that sandwiches the thrust bearing 5 from both sides in the rotation axis direction. The contact surface in the rotation axis direction between the thrust bearing 5 and the engaging portion 6 a is a surface that receives the force in the rotation axis direction of the rotating body 2. Thus, in the present embodiment, the turbine shaft 25, the impeller 26, the collar 6, and the nut body 30 that are supported by the turbine shaft 25 are configured as the rotating body 2 that rotates integrally. .

  The turbine wheel portion 22 that is a portion protruding from the housing 3 is covered by the turbine housing 7. The turbine housing 7 is attached to one side of the housing 3 (the side from which the turbine wheel portion 22 protrudes, the right side in FIG. 1). Further, the compressor wheel portion 23 which is a portion protruding from the housing 3 is covered with a compressor housing (not shown) when the turbocharger 1 is mounted and used in an engine. The compressor housing is attached to the other side of the housing 3 (the side from which the compressor wheel portion 23 protrudes, the left side in FIG. 1). However, the unbalance of the turbocharger 1 is corrected with the compressor housing removed.

  The turbocharger 1 having such a configuration functions as follows when mounted on the engine. That is, the exhaust from the engine is guided into the turbine housing 7 through the exhaust passage of the engine. Due to the exhaust of the engine flowing into the turbine housing 7, the rotating body 2 rotates about the turbo rotation axis C <b> 1 by obtaining rotational power by the turbine wheel portion 22.

  On the other hand, air (intake air) supplied to the engine is filtered by an air cleaner or the like and then guided into the compressor housing covering the impeller 26 as described above via the intake passage of the engine. The air that has flowed into the compressor housing is compressed and supplied (supercharged) to the engine by the compressor wheel portion 23 (impeller 26) that rotates as the rotating body 2 rotates due to exhaust from the engine. The compressed air is cooled by an intercooler and then sucked into the combustion chamber of the engine via the engine intake passage.

  Unbalance correction is performed for the turbocharger 1 having the above-described configuration. In the unbalance correcting method for the turbocharger 1 according to the present embodiment, a space having a predetermined shape is provided at a predetermined position in the rotating body 2 when correcting the unbalance. And the paste-form or liquid fluid material which will be in the state fixed to the wall surface which forms the said space while it hardens | cures by being heated in the space provided in the rotary body 2 is put. Hereinafter, a space provided in the rotating body 2 and in which a fluid material is placed is referred to as a “material holding space” for convenience.

  In the present embodiment, the material holding space is provided in the nut body 30 for fixing the impeller 26 constituting the compressor wheel portion 23 to the turbine shaft 25 in the rotating body 2. That is, in the present embodiment, the nut body 30 corresponds to a fixing member for fixing the impeller 26 to the turbine shaft 25. Moreover, in this embodiment, the silver nano paste (Ag nano paste) 40 is used as a fluid material put into the material holding space.

  As shown in FIGS. 2 to 5, the nut body 30 has a function as a general hex nut. That is, the nut body 30 has an outer peripheral surface 30a that is hexagonal when viewed in the axial direction (see FIGS. 2 and 5) and a screw portion 30b that is formed on the inner peripheral surface. The nut body 30 engages the impeller 26 with the screw portion 30b engaged with a screw portion (not shown) formed on the outer peripheral surface of the reduced diameter portion 25b (see FIG. 1) of the turbine shaft 25. Is fixed to the turbine shaft 25. Thus, the material holding space 31 into which the silver nano paste 40 is put is formed in the nut body 30 having a function as a hexagon nut.

  In the nut body 30, the material holding space 31 is formed inside a main body portion (portion that forms the outer peripheral surface 30 a and the screw portion 30 b). That is, the nut body 30 is configured as a hollow member that has an outer shape as a hexagonal nut and forms the material holding space 31.

  In the present embodiment, the material holding space 31 has an annular shape. That is, the material holding space 31 includes, as wall surfaces forming the space, an inner side surface 31a that is a cylindrical outer peripheral surface, an outer side surface 31b that is a cylindrical inner peripheral surface, and an axial direction of the nut body 30 (see FIG. 4 and the side surface 31c which is an annular plane formed on both sides of the axial center line C2.

  The shape of the material holding space 31 is not limited to the shape of the present embodiment (annular shape). The shape of the material holding space 31 may be a rotational shape around the turbo rotation axis C1. In other words, the shape of the material holding space 31 may be an axial rotation shape that is symmetric around the turbo rotation axis C1. In other words, the rotational shape centered on the turbo rotation axis C1 is a shape corresponding to a locus drawn by rotating a predetermined planar shape about the turbo rotation axis C1. Therefore, the material holding space 31 has a shape that is continuous (communicated) in the circumferential direction so that the silver nanopaste 40 can move over the entire circumference.

  In the present embodiment, the material holding space 31 has a quadrangular shape formed by the inner side surface 31a, the outer side surface 31b, and both side surfaces 31c in the sectional view shown in FIG. It has an annular shape corresponding to the locus drawn. Such an annular shape is a rotational shape around the turbo rotation axis C1 in a state where the nut body 30 is supported by the turbine shaft 25, that is, in a state where the axial center line C2 of the nut body 30 coincides with the turbo rotation axis C1. Become.

  As the shape of the material holding space 31 having a rotational shape around the turbo rotation axis C1, in addition to the annular shape of the present embodiment, a cylindrical shape, a conical shape, a partial shape of a cone, a spherical shape, a spindle shape, and the like A shaft rotation shape may be employed. As described above, the use of the shaft rotation shape as the shape of the material holding space 31 eliminates the influence on the balance of the rotating body 2 (occurrence of unbalance) due to the provision of the material holding space 31 in the rotating body 2. Based on perspective.

  As described above, the material holding space 31 provided in the nut body 30 is provided so as not to cause unbalance in the rotating body 2. Moreover, in this embodiment, when the nut body 30 is used for the structure of the rotary body 2, the silver nano paste 40 is previously enclosed in the nut body 30 (material holding space 31). The amount of the silver nanopaste 40 that is put into the material holding space 31 is not particularly limited, but is an amount that does not fill the material holding space 31 with the silver nanopaste 40 at most (see FIGS. 4 and 5).

  In this embodiment, the silver nanopaste used as a fluid material placed in the material holding space 31 is a dispersing agent (organic) in which silver (Ag) fine particles (Ag nanoparticles) having a particle size of, for example, about 10 nm are made of a resin or the like. It is in the form of a paste dispersed in a solvent while being coated with a protective film. In the silver nanopaste, when the silver nanopaste is heated and reaches a certain temperature (the melting point of the dispersant (for example, around 200 ° C.)), the organic protective film and the solvent are decomposed and volatilized to form fine silver particles. Appear, and silver fine particles are bonded to each other.

  That is, when the silver nanopaste is heated and reaches a predetermined temperature, it is sintered (cured) by the particle effect (decrease in melting point) to become a silver solid. Here, the temperature at which the silver nano paste is sintered is lower than the melting point of silver diffused as fine particles in the solvent. Silver nanopaste utilizes the above properties, and is used, for example, as an adhesive or a bonding material.

  Thus, the silver nano paste 40 put in the material holding space 31 of the nut body 30 in the present embodiment is hardened by being heated and is in a state of being fixed to the wall surface forming the material holding space 31. It is a fluid material. That is, the silver nano paste 40 is sintered (cured) by being heated and reaching a predetermined temperature (for example, a temperature of 200 ° C. or higher).

  As described above, in the unbalance correction method of the present embodiment, the rotating body 2 is provided with the material holding space 31 having an annular shape that is a rotational shape around the turbo rotation axis C1, and this material holding space. The silver nano paste 40 is put into the state 31. And in this state, the rotation process which rotates the rotary body 2 by more than predetermined | prescribed rotation speed, and the heating process which heats the silver nano paste 40 are performed.

  The rotating step is a step of rotating the rotating body 2 at a predetermined number of rotations or more in order to cause the silver nano paste 40 to flow and be unevenly distributed in the material holding space 31 at a position that cancels the unbalance of the rotating body 2. is there. That is, since the silver nanopaste 40 is a paste-like material having fluidity, the nut body 30 is rotated (rotated) in the material holding space 31 by the rotation of the rotating body 2. And if the rotation speed of the rotary body 2 becomes more than a certain rotation speed, the silver nano paste 40 will move in the direction which cancels the unbalance of the rotary body 2. Such a phenomenon is based on the following principle.

  In the turbocharger 1, when the rotating body 2 rotates, resonance occurs depending on the number of rotations of the rotating body 2 as a vibration characteristic of the device accompanying the rotation of the rotating body 2. This resonance is due to the fact that the natural frequency of the turbocharger 1 matches the rotation frequency of the rotating body 2 as the rotating body 2 rotates.

  FIG. 6A is a graph showing an example of the relationship between the rotation speed and the amplitude of the rotating body 2. As can be seen from the graph of FIG. 6A, the resonance (primary resonance) associated with the rotation of the rotating body 2 occurs at the rotation speed N1 where the rotation speed of the rotating body 2 is the resonance rotation speed. That is, the change in the amplitude value in the rotation speed region including the resonance rotation speed (the rotation speed N1) is represented by a mountain-shaped graph having the amplitude value at the rotation speed N1 as a peak value. Hereinafter, the rotation speed (rotation speed N1) at which primary resonance (hereinafter simply referred to as “primary resonance”) accompanying the rotation of the rotating body 2 occurs is referred to as “primary resonance point” with respect to the rotation speed of the rotating body 2.

  Then, in the rotation speed region including the primary resonance point, the phase of vibration of the rotating body 2 (hereinafter simply referred to as “phase”) is reversed. FIG. 6B is a graph showing an example of the relationship between the rotational speed and the phase of the rotating body 2. As shown in FIG. 6B, the phase of the rotator 2 is reversed via the primary resonance point. That is, for example, in the process of increasing the rotational speed of the rotating body 2, the stable phase before the primary resonance occurs is θ1, the stable phase after the rotational speed of the rotating body 2 exceeds the primary resonance point and the primary resonance occurs. Assuming that θ2, there is a 180 ° difference (reversed 180 °) between θ1 and θ2.

  Thus, when the rotation speed of the rotating body 2 increases until it exceeds the primary resonance point, the phase of the rotating body 2 is reversed. Based on the vibration characteristics of the rotating body 2, the behavior of the silver nanopaste 40 in the material holding space 31 accompanying the change (increase) in the rotational speed of the rotating body 2 will be described with reference to FIG. 7. In this description, as shown in FIG. 7, the unbalance of the rotating body 2 is expressed assuming that the unbalance component ub exists in a predetermined phase with the turbo rotation axis as the center.

  As shown in FIG. 7A, in a state before the rotation of the rotating body 2, that is, in a state where the rotating body 2 is stopped, the silver nanoparticle enclosed in the material holding space 31 of the nut body 30. The paste 40 is accumulated in a predetermined position (a lower position in FIG. 7) due to its own weight (gravity). As shown in FIG. 7B, when the rotating body 2 starts to rotate (see arrow D), the silver nanopaste 40 spreads along the outer surface 31b that forms the material holding space 31 by centrifugal force.

  In the process of increasing the rotational speed of the rotator 2, before the rotational speed of the rotator 2 exceeds the primary resonance point, as shown in FIG. 7 (c), the silver nano paste 40 is on the same side as the unbalance component ub. It is unevenly distributed. That is, before the rotational speed of the rotating body 2 exceeds the primary resonance point, the silver nanopaste 40 and the unbalance component ub exist in the same phase (same direction).

  Then, after the rotational speed of the rotating body 2 exceeds the primary resonance point, the silver nanopaste 40 moves in a phase (opposite direction) opposite to the unbalance component ub, as shown in FIG. 7 (d). To do. That is, as described above, when the rotational speed of the rotating body 2 exceeds the primary resonance point, the phase of the rotating body 2 is inverted, while the phase of the silver nanopaste 40 in the material holding space 31 is not inverted. For this reason, when the rotation speed of the rotating body 2 exceeds the primary resonance point, the silver nanopaste 40 cancels out the phase opposite to the unbalanced component ub, that is, the unbalance of the rotating body 2. It moves to (cancellation position) and becomes unevenly distributed (hereinafter referred to as “an unbalance improvement state”). Such a phenomenon is in principle common to the fluid balance of the washing machine dewatering tub.

  FIG. 7D shows a state in which the silver nanopaste 40 is moved in an inverted manner relative to the unbalance component ub in the relationship with FIG. 7C to 7D, the point C3 represents the center of the rotating body 2, that is, the position of the turbo rotating shaft C1 (see FIG. 1), and the point C4 has the unbalanced rotating body 2. This is a virtual center of rotation when the bending of the shaft about the rotating body 2 is taken into consideration.

  In the rotation process, the rotating body 2 is rotated by driving with air (air drive). That is, as described above, as in the case of exhaust from the engine when the turbocharger 1 functions in a state where it is mounted on the engine, when the rotating body 2 is rotated in the rotation process, a predetermined value (not shown) is provided in the turbine housing 7. Air is supplied from the air source (see arrow A1 in FIG. 1). Then, due to the air flowing into the turbine housing 7, the rotating body 2 obtains rotational power by the turbine wheel portion 22 and rotates around the turbo rotation axis C <b> 1 (see arrow A <b> 2 in FIG. 1).

  In addition, the rotation of the rotating body 2 in the rotating step is the number of rotations that is equal to or higher than the primary resonance point (the number of rotations N1) and the phase of the rotating body 2 is reversed (for example, FIG. The rotation speed N2) shown in b) is used as the target rotation speed.

  The heating step is a step of heating the silver nano paste 40 in order to cure the silver nano paste 40 in a state of being unevenly distributed in the material holding space 31 by the rotation step and fix the silver nano paste 40 to the wall surface forming the material holding space 31. . That is, as described above, the silver nanopaste 40 is heated and reaches a predetermined temperature to sinter (harden) and become a solid. The silver nano paste 40 is fixed in a wall surface forming the material holding space 31 by being sintered in the material holding space 31.

  Therefore, in the heating process, heating for sintering the silver nanopaste 40 in a state where the unbalance of the silver nanopaste 40 is improved by the rotation process, that is, in a state where the rotating body 2 is rotating at a rotation speed equal to or higher than the primary resonance point. Is done. Thereby, the silver nano paste 40 is fixed to the nut body 30 in an unbalance improved state, and a state in which the unbalance is corrected for the rotating body 2 is obtained.

  In the present embodiment, as shown in FIG. 1, the high frequency coil 10 is used as a means for heating the silver nano paste 40 in the nut body 30. The high frequency coil 10 is provided around the nut body 30 that is supported by the turbine shaft 25 in the turbocharger 1. That is, the silver nano paste 40 in the nut body 30 is heated by the high frequency coil 10 through the nut body 30. The high frequency coil 10 is disposed at a position suitable for heating the nut body 30 without preventing the rotation of the rotating body 2. The high-frequency coil 10 heats the silver nanopaste 40 so as to reach at least a temperature at which the silver nanopaste 40 in the nut body 30 is sintered (for example, a temperature of 200 ° C. or higher).

  As described above, the heating process performed using the high-frequency coil 10 is performed in the unbalanced state of the silver nanopaste 40 (see FIG. 7D) by the rotation process as described above. Then, the silver nanopaste 40 in the unbalance improved state is heated and sintered in the heating step, so that the unbalance improved state is fixed to the nut body 30 in the material holding space 31. As a result, as shown in FIG. 7 (e), the rotation of the rotating body 2 is stopped, so that the unbalanced state of the rotating body 2 is corrected.

  As described above, in the present embodiment, as a configuration for correcting the unbalance of the turbocharger 1, the nut body 30 that holds the silver nanopaste 40 and the silver nanopaste 40 in the nut body 30 are heated. The high frequency coil 10 is used. In such a configuration, the nut body 30 has a material holding space 31 for holding the silver nanopaste 40, and constitutes the rotating body 2 while being supported by the turbine shaft 25. The high-frequency coil 10 is configured to heat and sinter the silver nanopaste 40 in an unbalance-improved state in the nut body 30 and fix it to the nut body 30.

  In the heating process, the means for heating the silver nano paste 40 in the nut body 30 is not limited to the high frequency coil 10 of the present embodiment. As a means for heating the silver nano paste 40, a known method can be appropriately employed as long as the silver nano paste 40 in the nut body 30 can be heated until it is sintered.

  The unbalance correction method of this embodiment is demonstrated using the flowchart shown in FIG. In the unbalance correction method of the present embodiment, first, the nut body 30 is used, and the turbocharger 1 is assembled (S110). That is, the rotating body 2 is configured by using the nut body 30 and fixing the impeller 26 to the turbine shaft 25 via the collar 6. The rotating body 2 is rotatably supported with respect to the housing 3 by using a radial bearing 4 and a thrust bearing 5. A turbine housing 7 is attached to the housing 3. In addition, the silver nano paste 40 is previously enclosed in the nut body 30 used here.

  Next, the rotating body 2 is rotated by the air drive at a rotation speed equal to or higher than the primary resonance point (S120). That is, the rotating body 2 obtains rotational power by the turbine wheel portion 22 by the air supplied into the turbine housing 7 and rotates about the turbo rotation axis C1. Here, the rotational speed of the rotating body 2 above the primary resonance point is, for example, about 70,000 rpm.

  When the rotational speed of the rotating body 2 becomes equal to or higher than the primary resonance point, the phase of the rotating body 2 is reversed, and the silver nano paste 40 in the nut body 30 moves in a direction to reduce the unbalance of the rotating body 2. (S130). That is, when the rotating body 2 rotates at a rotational speed equal to or higher than the primary resonance point, the silver nanopaste 40 in the material holding space 31 is in an unbalance improved state.

  Subsequently, the high frequency coil 10 heats the nut body 30 at a high frequency (for example, 200 ° C. or higher), whereby the silver nano paste 40 is sintered and fixed (S140). That is, when the rotating body 2 rotates at a rotational speed equal to or higher than the primary resonance point, the silver nanopaste 40 in an unbalance improved state is heated by the high-frequency coil 10 via the nut body 30, It will be in the state fixed to the nut body 30 in the balance improvement state.

  Then, the rotation of the rotating body 2 is stopped, and the unbalance correction for the turbocharger 1 is finished (S150). Thereby, the state where the imbalance was corrected about the rotary body 2 is obtained. In the flow of the unbalance correction method of the present embodiment, steps S120 and S130 correspond to the rotation process described above, and step S140 corresponds to the heating process described above.

  According to the unbalance correcting method of the turbocharger 1 of the present embodiment as described above, steps that are prone to error, such as a step in which unbalance is calculated and a step in which balance is adjusted by cutting or the like, are performed. This can be omitted, and the imbalance correction accuracy can be improved. The fact that such an effect is obtained will be described by comparison with a conventional unbalance correction method (hereinafter referred to as “conventional method”).

  A conventional method will be described with reference to FIGS. 25 and 26. FIG. In the description of the conventional method, for the sake of convenience, the configuration of the turbocharger 1 of the present embodiment is partially quoted using the same reference numerals.

  As shown in FIG. 25, in the conventional method, when the unbalance is corrected, the rotating body 2 is rotated at a predetermined rotational speed by an air drive as in the case of the present embodiment. In a state where the rotating body 2 is rotating, the acceleration pickup 101 detects vibration acceleration, and the phase detector 102 detects the rotation angle (phase) of the rotating body 2.

  A predetermined number (two in FIG. 25) of the acceleration pickups 101 is provided at a predetermined position in the housing 3. The acceleration pickup 101 is composed of, for example, an acceleration sensor, and detects (pickup) vibration acceleration at a predetermined position of the housing 3. Based on the value of the vibration acceleration detected by the acceleration pickup 101, the unbalance amount of the rotating body 2 is measured.

  The phase detector 102 detects the rotation angle of the rotating body 2 by detecting the rotation of the impeller 26 fixed to the turbine shaft 25. The phase detector 102 includes a non-contact rotational displacement (rotational angle) sensor such as an optical sensor or a magnetic sensor.

  Thus, the acceleration pickup 101 and the phase detector 102 provided for the turbocharger 1 are used to detect the vibration acceleration and the rotation angle of the rotating body 2 when the rotating body 2 is rotating at a predetermined rotational speed. And measured. Then, based on the measured vibration acceleration and the rotation angle of the rotating body 2, the amount and phase of unbalance of the rotating body 2 are measured by an arithmetic device or the like. As described above, in the conventional method, the unbalance of the rotating body 2 is calculated based on the detection values by the acceleration pickup 101 and the phase detector 102.

  Then, based on the measured unbalance amount and phase, the balance of the rotating body 2 is adjusted (imbalance correction). The balance of the rotating body 2 is adjusted by cutting and removing a predetermined portion (a portion corresponding to the unbalance) in the nut 130 used for fixing the impeller 26 to the turbine shaft 25. As shown in FIG. 25, the nut 130 is cut using an NC machine tool 103 such as an end mill.

  The conventional method will be described with reference to the flowchart shown in FIG. In the conventional method, first, the nut 130 is used to assemble the turbocharger 1 (S510). Next, the rotating body 2 is rotated by the air drive, and the acceleration (vibration acceleration) and phase at the primary resonance point are measured using the acceleration pickup 101 and the phase detector 102 (S520).

  Then, the rotation of the rotating body 2 is stopped (S530), and the unbalance amount of the rotating body 2 is measured based on the measured vibration acceleration (S540). Subsequently, the unbalance amount converted as the mass of the nut 130 from the measured unbalance amount is removed by cutting the nut 130 by the NC machine tool 103 (S550). Thereby, the balance of the rotary body 2 is adjusted.

  After the nut 130 is cut, the vibration (vibration acceleration) and phase at the primary resonance point are measured again in the same manner as in step S520 (S560). Then, until the unbalance measured based on the measured vibration and phase falls within a predetermined standard, the unbalance is measured and the nut 130 is cut (S570). That is, when the unbalance measured as described above is determined to be within the standard in step S570, the rotation of the rotating body 2 is stopped and the correction of the unbalance for the turbocharger 1 is completed. (S580).

  By the way, in correcting the unbalance of the turbocharger 1, it is necessary to remove the unbalance of the rotating body 2 in the assembly state of the turbocharger 1. That is, even if unbalance correction is performed for individual components (such as the turbine shaft 25 and the impeller 26) constituting the rotating body 2, there are bearing clearances in the turbocharger 1, clearances in the inlay portions of the assembled components, and the like. Therefore, the balance of the rotating body 2 as an assembly changes after assembly (after assembly). For this reason, it is necessary to correct the imbalance even after the turbocharger 1 is assembled.

  Further, in the turbocharger 1, since the vibration mode with respect to the vibration accompanying the rotation of the rotating body 2 is not a rigid body but an elastic body mode, an unbalance is also generated due to the bending (shaft bending) of the rotating body 2. Also from this point, it is necessary to correct the imbalance in the assembly state of the turbocharger 1.

  Therefore, according to the conventional method as described above, the imbalance of the turbocharger 1 in the assembly state is corrected. However, the conventional method has the following problems. That is, in the conventional method, after the unbalance is calculated based on the vibration acceleration and the detected value of the phase, the balance is adjusted (unbalance correction) by cutting the nut 130 based on the calculated value. . For this reason, in the conventional method, a calculation error in unbalance calculation and a processing error in balance adjustment occur. As a result, the number of times of unbalance correction is increased, and the imbalance correction accuracy is limited. In other words, in the conventional method, errors occurring in each process of the process where the unbalance is calculated and the process where the balance is adjusted accumulate, so it is difficult to improve the unbalance correction accuracy.

  On the other hand, in the unbalance correction method of the present embodiment, the rotating body 2 is configured using the nut body 30 enclosing the silver nanopaste 40, and the rotating body 2 is rotated at a rotational speed equal to or higher than the primary resonance point. By heating the silver nanopaste 40 to a predetermined temperature or higher by the high-frequency coil 10, a state where the unbalance is corrected for the rotating body 2 is automatically obtained. Therefore, according to the unbalance correction method of this embodiment, in order to correct the unbalance of the turbocharger 1, it is not necessary to perform unbalance measurement (vibration and phase detection), and removal by machining. There is no need for processing.

  For this reason, unlike the conventional method, the accumulation of errors in each process does not occur, and the imbalance can be corrected with high accuracy. By improving the unbalance correction accuracy, when the turbocharger 1 is mounted on the engine and functions, it is possible to reduce the vibration level and improve the upper limit operating rotational speed (improve the operating efficiency).

  Further, as described above, since it is not necessary to perform unbalance measurement or excision by machining, the process can be omitted, and the process for correcting the unbalance can be shortened. Specifically, for example, in order to ensure the quality of the turbocharger 1, vibration measurement may be required in the final process of the turbocharger 1 manufacturing process. It is possible to respond by only measuring the value. On the other hand, when vibration measurement is not required in the final process or the like, a special process for excision by unbalance measurement or machining is not required.

  A second embodiment of the present invention will be described. In each embodiment described below, for the sake of convenience, portions common to the first embodiment described above are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  In the present embodiment, in the nut body 30, after the nut body 30 is used and the rotating body 2 is configured (after the nut body 30 is tightened to the turbine shaft 25), silver is placed in the nut body 30 (the material holding space 31). A configuration in which the nano paste 40 can be injected is employed. And in order to correct the measured unbalance amount, the unbalance amount about the rotary body 2 constituted by using the nut body 30 in which the silver nano paste 40 is not put in the material holding space 31 is used. A necessary amount of silver nano paste 40 is injected into the material holding space 31 and used.

  Therefore, as shown in FIGS. 9 and 10, in this embodiment, the nut body 30 which is a member forming the material holding space 31 is provided with an injection port 32 for putting the silver nano paste 40 into the material holding space 31. It is done. The injection port 32 is provided on an end surface portion on one side (left side in FIG. 10) of the nut body 30 in the axial direction (the direction of the axial center line C2 in FIG. 10).

  The injection port 32 opens the material holding space 31. The inlet 32 is formed as an annular opening centered on the axial center position of the nut body 30 at one end surface of the nut body 30. The injection port 32 is a state in which the nut body 30 is used to form the rotating body 2, that is, in a state in which the nut body 30 is fastened to the turbine shaft 25, It is provided at a position where the paste 40 can be injected. Therefore, the end surface portion where the injection port 32 is provided in the nut body 30 corresponds to the end surface portion opposite to the impeller 26 side in a state where the nut body 30 is fastened to the turbine shaft 25.

  The inlet 32 is not affected by the balance of the rotating body 2 including the nut body 30, and also when the nut body 30 supported by the turbine shaft 25 rotates as the rotating body 2 rotates. If the nano paste 40 is provided so as not to spill (so that the silver nano paste 40 is held), the shape and the position where the nano paste 40 is provided are not limited. For example, the inlet 32 may be provided as a plurality of openings, or may be provided so as to open to the outer peripheral surface 30 a of the nut body 30.

  In this state where the rotating body 2 configured using the nut body 30 having the injection port 32 is supported by the housing 3 (the assembly state of the turbocharger 1), the silver nano-particles are transferred from the injection port 32 to the material holding space 31. Paste 40 is injected. Specifically, as shown in FIG. 11, an injection nozzle 41 is used to inject the silver nanopaste 40 from the injection port 32.

  The injection nozzle 41 has a configuration in which the silver nano paste 40 can be put into the material holding space 31 of the nut body 30 through the injection port 32. As such a configuration, for example, a tubular portion that can be inserted into the injection port 32 is provided at the tip of the injection nozzle 41. And the silver nano paste 40 is inject | poured in the state which the tubular part which this injection | pouring nozzle 41 has was inserted in the material holding space 31 via the injection inlet 32. FIG.

  In the unbalance correcting method of the present embodiment in which the configuration as described above is used, before the rotating step of rotating the rotating body 2 in order to make the silver nano paste 40 in the nut body 30 in an unbalance improving state, A measurement process for measuring the amount of unbalance of the rotating body 2 and an injection process for putting the silver nanopaste 40 into the material holding space 31 from the injection port 32 are performed.

  In the measurement process, the rotation of the rotating body 2 is detected by detecting the vibration associated with the rotation of the rotating body 2 in a state where the rotating body 2 in which the silver nanopaste 40 is not placed in the material holding space 31 is rotated at a predetermined rotational speed. It is a step of measuring the amount of unbalance. That is, in this process, the rotating body 2 is configured using the nut body 30 in which the silver nano paste 40 is not put, and the turbocharger 1 is assembled.

  In the measurement process, the unbalance amount of the rotating body 2 is measured using the acceleration pickup 42. As shown in FIG. 11, the acceleration pickup 42 is provided at a predetermined position in the housing 3, for example. In the present embodiment, the acceleration pickups 42 are provided at two locations on the outer peripheral surface portion of the housing 3 at a predetermined interval in the rotation axis direction. However, the position and the number of the acceleration pickups 42 are not limited.

  The acceleration pickup 42 is configured by, for example, an acceleration sensor and detects (pickup) vibration acceleration at a predetermined position of the housing 3. Based on the vibration acceleration value detected by the acceleration pickup 42, the unbalance amount of the rotating body 2 is measured by an arithmetic device or the like.

  When measuring the unbalance amount of the rotating body 2, the rotating body 2 is rotated at a predetermined rotational speed. For example, a primary resonance point is used as the predetermined rotational speed of the rotating body 2 here. However, when measuring the unbalance amount of the rotating body 2, a rotational speed other than the primary resonance point (frequency other than the primary resonance) is appropriately used according to the vibration standard or the like.

  The injection step is a step of putting silver nanopaste 40 in an amount corresponding to the unbalance amount of the rotating body 2 measured in the measurement step into the material holding space 31 from the injection port 32 of the nut body 30. That is, in this step, the amount of silver nano paste 40 necessary to cancel the measured unbalance amount is calculated from the unbalance amount of the rotating body 2 measured in the measurement step.

  With respect to the silver nanopaste 40, the amount necessary to cancel out the unbalance amount of the rotating body 2 is an amount that can cancel the measured unbalance amount of the rotating body 2. The relationship between the unbalanced amount of the rotating body 2 to be measured and the required amount of the silver nanopaste 40 corresponding thereto is obtained in advance by experiments or the like based on the density or the like of the silver nanopaste 40. The required amount of the silver nanopaste 40 is, for example, an amount (mass) corresponding to the mass of the portion where the nut 130 is cut and removed based on the unbalance amount measured in the conventional method.

  The unbalance correction method of this embodiment is demonstrated using the flowchart shown in FIG. In the unbalance correction method of the present embodiment, in comparison with the flow (see FIG. 8) in the case of the first embodiment, before step S120 in which the rotating body 2 is rotated by the air drive at a rotational speed equal to or higher than the primary resonance point. In addition, the measurement process and the injection process as described above are performed.

  That is, in the unbalance correction method of this embodiment, first, the nut body 30 having the inlet 32 is used, and the turbocharger 1 is assembled in the same manner as in the first embodiment (S110). However, the silver nano paste 40 cannot be put in the nut body 30 at this stage.

  Next, the rotating body 2 is rotated at a predetermined rotational speed (for example, a primary resonance point) by the air drive, and the unbalance amount of the rotating body 2 is measured based on the detection value by the acceleration pickup 42 (S111). From the measured unbalance amount of the rotator 2, an amount necessary for offsetting the unbalance amount of the rotator 2 is calculated for the silver nanopaste 40 (S112).

  And after rotation of the rotary body 2 is stopped, the silver nano paste 40 is inject | poured from the injection port 32 of the nut body 30 (S113). That is, the necessary amount of silver nanopaste 40 calculated in step S112 is put into the material holding space 31 by the injection nozzle 41 through the injection port 32.

  After the required amount of silver nanopaste 40 is injected into the nut body 30, the rotation process (S120, S130) and the heating process (S140) are performed in the same manner as in the first embodiment, and the turbocharger 1 The unbalance correction for is finished (S150).

  According to the unbalance correcting method of the present embodiment, only the amount of silver nanopaste 40 necessary for correcting the unbalance of the rotating body 2 is used, so that the amount of silver nanopaste 40 can be optimized. it can. Thereby, reduction of material cost can be aimed at.

  Further, by optimizing the amount of the silver nanopaste 40, the amount of the silver nanopaste 40 used for correcting the unbalance, that is, the mass added to the rotating body 2 for correcting the unbalance is increased. Since it is suppressed, a reduction in the natural frequency can be suppressed. Therefore, for example, in comparison with the first embodiment, even if the unbalance correction amount is the same, the vibration level in the turbocharger 1 can be further reduced, and the upper limit operating speed can be improved (the operating efficiency can be improved). It becomes.

  Further, in comparison with the above-described conventional method, it is not necessary to detect and measure the phase for the unbalance of the rotator 2, so that the process for correcting the unbalance can be shortened.

  A third embodiment of the present invention will be described. In the present embodiment, a material holding space in which the silver nano paste 40 is placed is provided on the turbine wheel portion 22 side in the rotating body 2.

  That is, as shown in FIG. 13, in the present embodiment, the turbine wheel portion 22 is provided by fixing a turbine wheel 27 as a wheel member to the turbine shaft 25. A material holding space 36 is provided between the turbine shaft 25 and the turbine wheel 27.

  Specifically, as shown in FIG. 14, the state in which the turbine wheel 27 is fixed to the turbine shaft 25 includes a fitting recess 27 </ b> A provided in the turbine wheel 27 and a fitting protrusion 25 </ b> A provided in the turbine shaft 25. Are in a fitted state. As the wall surface forming the material holding space 36 provided between the turbine shaft 25 and the turbine wheel 27, the bottom surface 27c and the inner peripheral surface 27d of the fitting recess 27A and the tip surface 25c of the fitting projection 25A are used. .

  The fitting recess 27A provided in the turbine wheel 27 is a recess that opens to one side (left side in FIG. 14) in the rotation axis direction. The fitting recess 27 </ b> A is formed as a portion protruding in a cylindrical shape from the side fixed to the turbine shaft 25 in the turbine wheel 27. Accordingly, the fitting recess 27A has a bottom surface 27c and an inner peripheral surface 27d. A space portion formed by the bottom surface 27c and the inner peripheral surface 27d in the fitting recess 27A has a cylindrical shape. The fitting recess 27A is a central axis of a cylindrical space formed by the bottom surface 27c and the inner peripheral surface 27d in a state where the turbine wheel 27 constitutes the rotating body 2 (a state where the turbine wheel 27 is fixed to the turbine shaft 25). (Cylinder shaft of the fitting recess 27A) is formed so as to coincide with the turbo rotation shaft C1 (see FIG. 13).

  The fitting protrusion 25A provided on the turbine shaft 25 is a protrusion protruding to the other side (right side in FIG. 14) in the rotation axis direction. 25 A of fitting protrusions are formed in the turbine shaft 25 as a part which protrudes in a column shape from the side to which the turbine wheel 27 is fixed. In other words, the fitting protrusion 25 </ b> A is a reduced diameter portion formed at the end of the shaft-like turbine shaft 25. Therefore, the fitting protrusion 25A has a tip surface 25c and an outer peripheral surface 25d. The fitting protrusion 25A is a state in which the turbine shaft 25 constitutes the rotating body 2 (a state in which the turbine wheel 27 and the like are fixed to the turbine shaft 25), and the cylindrical center axis is the turbo rotation axis C1 (FIG. 13). Reference) is formed.

  Thus, the fitting recess 27A provided on the turbine wheel 27 and the fitting protrusion 25A provided on the turbine shaft 25 are fitted to each other by inserting the fitting protrusion 25A into the fitting recess 27A. Therefore, the inner diameter of the fitting recess 27A and the outer diameter of the fitting protrusion 25A are substantially the same as long as the fitting protrusion 25A can be inserted into the fitting recess 27A.

  Then, in a state where the fitting concave portion 27A and the fitting protrusion 25A are fitted, the bottom surface 27c of the fitting concave portion 27A and the front end surface 25c of the fitting protrusion 25A oppose each other with a space therebetween, and rotate. The body 2 is a surface perpendicular to the turbo rotation axis C1. Thereby, the material holding space 36 is formed by the bottom surface 27c and the inner peripheral surface 27d (a part thereof) of the fitting recess 27A and the tip surface 25c of the fitting protrusion 25A. Therefore, the material holding space 36 has a cylindrical shape, and this cylindrical shape is a rotational shape centered on the turbo rotation axis C1. Thus, the silver nano paste 40 is enclosed in the material holding space 36 provided between the turbine shaft 25 and the turbine wheel 27.

  In this embodiment, the turbine wheel 27 is provided with a fitting recess 27A, and the turbine shaft 25 is provided with a fitting protrusion 25A, but the fitting protrusion such as the fitting protrusion 25A is provided on the turbine wheel 27 side. And a fitting recess such as a fitting recess 27A may be provided on the turbine shaft 25 side. That is, the state in which the turbine wheel 27 is fixed to the turbine shaft 25 is a fitting recess provided in one of the turbine shaft 25 and the turbine wheel 27 and a fitting provided in either the turbine shaft 25 or the turbine wheel 27. What is necessary is just to be set as the state which the fitting protrusion fitted.

  In addition, the fitting shape between the fitting recess 27A and the fitting protrusion 25A and the shape of the material holding space 36 formed in a state where the fitting recess 27A and the fitting protrusion 25A are fitted are described in this embodiment. It is not limited to. The fitting recess 27A and the fitting protrusion 25A may have any shape that can be fitted to each other, and the shape of the material holding space 36 may be a rotational shape centered on the turbo rotation axis C1 as described above. . In the present embodiment, as shown in FIG. 13, a nut 28 that is a general hexagon nut is used as a member for fixing the impeller 26 to the turbine shaft 25 in the rotating body 2.

  In the present embodiment, the turbine shaft 25 and the turbine wheel 27 are fixed by being joined by electron beam welding. Specifically, as shown in FIG. 14, the fitting portion between the fitting recess 27A and the fitting protrusion 25A is a welded portion by electron beam welding. That is, the fitting portion between the fitting concave portion 27A and the fitting protrusion 25A becomes a superposed portion in the radial direction of the rotating body 2, and the superposed portion rotates, for example, from the outer peripheral surface side of the fitting concave portion 27A. An electron beam is irradiated toward the inside of the body 2 in the radial direction. Thereby, the portion irradiated with the electron beam is heated and melted, and the fitting recess 27A and the fitting projection 25A are welded (see the welded portion W). Electron beam welding is performed over the entire circumference or partially at the fitting portion between the fitting recess 27A and the fitting protrusion 25A.

  The method for fixing the turbine shaft 25 and the turbine wheel 27 is not particularly limited. The turbine shaft 25 and the turbine wheel 27 may be fixed by, for example, welding other than electron beam welding (laser welding or the like), a method using a fastening member such as a bolt, or the like.

  As described above, in the configuration in which the material holding space 36 is provided on the turbine wheel portion 22 side in the rotating body 2, as a means for heating the silver nano paste 40 in the material holding space 36, it is rotated in the above-described rotation process or the like. In order to rotate the body 2, the air (refer FIG. 13, arrow A1) supplied in the turbine housing 7 is used by making it high temperature. In other words, in the present embodiment, the heating of the silver nano paste 40 in the material holding space 36 provided between the turbine shaft 25 and the turbine wheel 27 in the heating process gives the rotational power of the rotating body 2 to provide the turbine wheel. This is performed by using a high temperature gas as the air supplied to the unit 22.

  The high-temperature gas used to heat the silver nanopaste 40 in the material holding space 36 is a gas having a temperature that is at least high enough to cure the silver nanopaste 40. Accordingly, the high-temperature gas for heating the silver nanopaste 40 heats the silver nanopaste 40 so as to reach at least a temperature at which the silver nanopaste 40 in the material holding space 36 is sintered (for example, a temperature of 200 ° C. or higher). The high-temperature gas for heating the silver nanopaste 40 is generated, for example, by heating the air used to rotate the rotating body 2 using a predetermined heat source.

  As in the present embodiment, by providing the material holding space 36 on the turbine wheel portion 22 side in the rotating body 2, the turbine housing 7 is used for rotating the rotating body 2 as a means for heating the silver nano paste 40. A hot gas supplied in the same manner as the air supplied inside can be used. Thereby, when the silver nano paste 40 is heated, there is no need to separately provide a configuration such as the high-frequency coil 10 (see FIG. 1) in the case of the first embodiment. However, also in the present embodiment, as a means for heating the silver nanopaste 40, any known method can be used as long as the silver nanopaste 40 in the material holding space 36 can be heated until it is sintered. A high frequency coil or the like) can be employed as appropriate.

  Further, as in the present embodiment, in the configuration in which the silver nano paste 40 is put in the material holding space 36 formed in a state in which the fitting recess 27A and the fitting protrusion 25A are fitted, it is heated and sintered. The silver nano paste 40 to be fixed becomes a “brazing material” for joining the turbine shaft 25 and the turbine wheel 27 together. That is, the silver nano paste 40 that is sintered and fixed in the material holding space 36 functions as an adhesive, whereby the turbine shaft 25 and the turbine wheel 27 are “brazed”.

  Specifically, as shown in FIG. 15A, the silver nanopaste 40 that is in an unbalance-improved state in the material holding space 36 by performing the rotation process and the heating process is a material holding space 36 by centrifugal force. It is fixed in a state along the inner peripheral surface 27d forming the. Therefore, the silver nano paste 40 sintered and fixed in the material holding space 36 is between the turbine shaft 25 and the turbine wheel between the front end surface 25c of the fitting protrusion 25A and the inner peripheral surface 27d of the fitting recess 27A. 27 is joined.

  Specifically, the silver nanopaste 40 that is in a state along the inner peripheral surface 27d by the centrifugal force due to the rotation of the rotating body 2 is a fitting surface between the turbine shaft 25 and the turbine wheel 27, that is, a fitting protrusion due to a capillary phenomenon. It enters between the outer peripheral surface 25d of 25A and the inner peripheral surface 27d of the fitting recess 27A. Here, as shown in FIG. 16, a tapered surface for facilitating insertion of the fitting projection 25A into the fitting recess 27A is provided at the tip peripheral edge portion (tip portion of the outer peripheral surface 25d) of the fitting projection 25A. 25e is formed. Therefore, the silver nano paste 40 that enters between the outer peripheral surface 25d and the inner peripheral surface 27d by capillary action from the inside of the material holding space 36 penetrates between the tapered surface 25e and the inner peripheral surface 27d. FIG. 16 is an enlarged view of a portion surrounded by a broken line E in FIG.

  Thus, the silver nano paste 40 that enters the fitting surface between the turbine shaft 25 and the turbine wheel 27 by the capillary phenomenon is sintered and fixed, whereby the outer peripheral surface 25d of the fitting protrusion 25A and the fitting recess 27A. The turbine shaft 25 and the turbine wheel 27 are joined together with the inner peripheral surface 27d. As a result, the turbine shaft 25 and the turbine wheel 27 are bonded to the front end surface 25c and the outer peripheral surface 25d (including the tapered surface 25e) of the fitting protrusion 25A and the fitting recess 27A by the silver nano paste 40 that is sintered and fixed. It will be in the state joined between inner peripheral surfaces 27d.

  As described above, in this embodiment, the silver nanopaste 40 put in the material holding space 36 provided between the turbine shaft 25 and the turbine wheel 27 in order to correct the imbalance of the rotating body 2 is the turbine shaft. 25 and the brazing material for joining the turbine wheel 27. Therefore, in the configuration in which the turbine shaft 25 and the turbine wheel 27 are joined by electron beam welding in a state where the fitting protrusion 25A and the fitting recess 27A are fitted, the stress caused by the rotation of the rotating body 2 at the joined portion. Concentration can be eased.

  That is, as shown in FIG. 15B, the joint portion of the fitting protrusion 25A and the fitting recess 27A by electron beam welding is connected to the non-melted portion (portion other than the welded portion W) of the rotating body 2. Stress due to centrifugal force accompanying rotation is concentrated (see arrow F2). Specifically, a portion surrounded by a broken line G in FIG. 15B is a stress concentration portion.

  Therefore, in the present embodiment, as described above, the silver nanopaste 40 that is sintered and fixed plays the role of a brazing material at the joint between the fitting protrusion 25A and the fitting recess 27A. The non-molten part of the joining part by beam welding is joined by the silver nano paste 40, and the joining by electron beam welding is reinforced. Thereby, the stress concentration accompanying the rotation of the rotating body 2 at the joint portion between the fitting protrusion 25A and the fitting recess 27A is relaxed (see arrow F1).

  Thus, in the present embodiment, in addition to the improvement of the imbalance correction accuracy, the following effects can be obtained. That is, according to the imbalance correction method of the present embodiment, the centrifugal strength strength around the electron beam welded portion between the turbine shaft 25 and the turbine wheel 27 can be improved, so that the upper limit operating rotational speed of the turbocharger 1 can be improved. (Improvement of operating efficiency) is possible.

  An example of the imbalance correction method of this embodiment will be described with reference to the flowchart shown in FIG. In the unbalance correction method of the present embodiment, the silver nano paste 40 is enclosed in the material holding space 36 when the rotating body 2 is sub-assembled (S210). That is, in the structure of the rotating body 2, when the turbine shaft 25 and the turbine wheel 27 are joined, the material holding space 36 formed in a state in which the fitting protrusion 25A and the fitting recess 27A are fitted to each other, Silver nano paste 40 is put.

  Next, the turbocharger 1 is assembled using the rotating body 2 in which the silver nano paste 40 is enclosed in the material holding space 36 (S220). Then, the rotating body 2 is rotated at a low speed by the air drive (S230), so that the silver nano paste 40 in the material holding space 36 enters the fitting surface between the turbine shaft 25 and the turbine wheel 27 by a capillary phenomenon. (S240).

  Here, the rotation speed of the rotating body 2 in step S230 is not particularly limited, but is lower than the primary resonance point, and the silver nano paste 40 forms the material holding space 36 by centrifugal force on the inner peripheral surface 27d. The rotation speed is such that the capillary action as described above is generated along the substantially entire circumference.

  Subsequently, the air for rotating the rotating body 2 is changed to a high-temperature gas (200 ° C. or higher), and the rotating body 2 is rotated at a rotation speed equal to or higher than the primary resonance point (S250). That is, the rotating body 2 is rotated by the high-temperature gas for heating the silver nanopaste 40 in the material holding space 36.

  When the rotational speed of the rotating body 2 is equal to or higher than the primary resonance point, the phase of the rotating body 2 is reversed, and the silver nanopaste 40 in the material holding space 36 reduces the unbalance of the rotating body 2. Move (S260). That is, the silver nano paste 40 is in an unbalance improved state. In addition, the timing etc. which change the air for rotating the rotary body 2 to high temperature gas are suitably set so that it may be fixed by sintering after the silver nano paste 40 will be in an unbalance improvement state.

  Then, after the silver nano paste 40 in the material holding space 36 is sintered and fixed by heat conduction from the high-temperature gas (S270), the rotation of the rotating body 2 is stopped, and the unbalance correction for the turbocharger 1 is corrected. The process ends (S280).

  Moreover, in this embodiment, in order to rotate the rotary body 2, the hot gas for heating the silver nano paste 40 from the beginning can be used. That is, in this case, the step of changing the air to the high temperature gas from the state where the rotary body 2 is rotated by the air drive is omitted, and the rotary body 2 is rotated by the high temperature gas from the beginning.

  When the rotating body 2 is rotated from the beginning with the high temperature gas, the rotation of the rotating body 2 is started by the high temperature gas until the silver nano paste 40 in the material holding space 36 is sintered and fixed by the high temperature gas (silver). The time (hereinafter referred to as “heat transfer time”) until the temperature at which the nanopaste 40 is sintered is measured in advance by experiments or the like. And the process in which the unbalance correction of the rotary body 2 is performed so that the time until the silver nano paste 40 in the material holding space 36 is in an unbalance improvement state by the rotation of the rotary body 2 is shorter than the heat transfer time. Each process (adjustment of the rotational speed of the rotating body 2 etc.) is performed.

  That is, in a case where a high temperature gas is used from the beginning before rotating the rotating body 2, the silver nano paste 40 is sintered and fixed before the silver nano paste 40 in the material holding space 36 is sintered and fixed by heat conduction from the high temperature gas. Time adjustment is performed so that 40 is in an unbalance improvement state. In other words, a high-temperature gas for rotating the rotating body 2 is used so that the silver nanopaste 40 is sintered after the silver nanopaste 40 in the material holding space 36 is in an unbalance improved state.

  Thus, the imbalance correction method in the case where the rotating body 2 is rotated by the high-temperature gas from the beginning is as shown in the flowchart of FIG. 18, for example. That is, in this case, as compared with the flowchart shown in FIG. 17, the rotating body 2 rotated at a low speed in the above-described step S230 is rotated by a high temperature gas (200 ° C. or higher) drive (S230).

  In contrast with the flowchart shown in FIG. 17 as well, the air is changed to the high temperature gas in step S250, whereas the gas remains as it is (the high temperature gas remains), and the rotating body 2 is above the primary resonance point. (S255). Other parts in the flowchart shown in FIG. 18 are the same as those shown in FIG.

  A fourth embodiment of the present invention will be described. In the present embodiment, a material holding space in which the silver nano paste 40 is put is provided in both the turbine wheel portion 22 side and the compressor wheel portion 23 side in the rotating body 2.

  That is, as shown in FIG. 19, in this embodiment, the compressor wheel portion 23 is provided by fixing the impeller 26 to the turbine shaft 25. Further, the turbine wheel portion 22 is provided by fixing a turbine wheel 27 as a wheel member to the turbine shaft 25.

  The impeller 26 is fixed to the turbine shaft 25 by using a nut body 30 (see FIGS. 2 to 5) that forms the material holding space 31, and holds the material between the turbine shaft 25 and the turbine wheel 27. A space 36 is provided. That is, this embodiment is a combination of the first embodiment and the third embodiment.

  Thus, in this embodiment, the material holding space in which the silver nanopaste 40 is put is provided between the nut body 30 for fixing the impeller 26 to the turbine shaft 25 and between the turbine shaft 25 and the turbine wheel 27. . In such a configuration, the imbalance correction accuracy can be further improved, and the vibration level can be reduced and the upper limit of the operating rotational speed of the turbocharger 1 can be increased.

  That is, in the turbocharger 1, the rotating body 2 rotates as an elastic body (the vibration mode associated with the rotation of the rotating body 2 is the mode of the elastic body). For this reason, in order to perform a more accurate unbalance correction, the material holding space in which the silver nano paste 40 is put is provided on both the turbine wheel portion 22 side and the compressor wheel portion 23 side, thereby correcting the unbalance. The “two-sided correction” performed is effective.

  Such two-sided correction is difficult in the conventional method as described above for the following reason. In order to rotate the rotating body 2 in the assembly state of the turbocharger 1, it is necessary to supply air into the turbine housing 7. Further, in the conventional method, in order to adjust the balance on the turbine wheel portion 22 side, it is necessary to cut a portion of the rotating body 2 that constitutes the turbine wheel portion 22.

  For this reason, in the conventional method, facilities and processes become complicated in order to achieve both supply of air for rotating the rotating body 2 and excision processing for balance adjustment. Moreover, since the turbine wheel 27 which comprises the turbine wheel part 22 is generally a difficult-to-work material, it is difficult to perform cutting on the turbine wheel part 22 side. As described above, in the conventional method, it is difficult to correct the two surfaces of the unbalance of the rotating body 2.

  In this regard, in the unbalance correction method according to the present invention, the unbalance correction of the rotating body 2 is automatically performed during the rotation of the rotating body 2 by using the silver nanopaste 40 as in the above embodiments. Done. From this, the difficulty for performing the two-surface correction in the conventional method is eliminated, and the two-surface correction can be easily performed.

  As a result, in the unbalance correction method of the present embodiment, the unbalance correction (one-surface correction) performed by providing a material holding space on either the turbine wheel portion 22 side or the compressor wheel portion 23 side of the rotating body 2. ), It is possible to improve the imbalance correction accuracy. In the present embodiment in which the rotating body 2 is configured by using the nut body 30 that forms the material holding space 31, unbalance correction (first operation) that is performed using the injection port 32 formed in the nut body 30. The second embodiment) can of course be applied.

  In each of the following embodiments, a preferable embodiment in a configuration in which unbalance correction is performed on the turbine wheel portion 22 side (a material holding space 36 is provided) as in the third embodiment and the fourth embodiment will be described.

  A fifth embodiment of the present invention will be described. In the present embodiment, in the rotating body 2, the turbine wheel 27 is fixed to the turbine shaft 25 by press-fitting. A clearance communicating with the material holding space 36 is provided in a press-fitted portion between the turbine shaft 25 and the turbine wheel 27.

  That is, in this embodiment, as shown in FIG. 20, the fitting between the fitting recess 27A of the turbine wheel 27 and the fitting projection 25A of the turbine shaft 25 is press-fitting the fitting projection 25A into the fitting recess 27A. It is said. And the clearance gap 37 connected to the material holding space 36 is formed by providing the reduced diameter part 25B in the front end side of the protrusion direction (right direction in FIG. 20) of the fitting protrusion 25A in the fitting protrusion 25A. .

  Regarding the press-fitting of the fitting projection 25A into the fitting recess 27A, the fitting portion between the fitting recess 27A and the fitting projection 25A is used as the press-fitting portion. That is, the inner peripheral surface 27d of the fitting recess 27A and the outer peripheral surface 25d of the fitting protrusion 25A serve as an engagement surface (joint surface) during press-fitting. In addition, the press-fitting of the fitting protrusion 25A into the fitting recess 27A can withstand at least the number of rotations of the rotating body 2 in the rotation process (for example, the number of rotations equal to or higher than the primary resonance point) with respect to the turbine shaft 25. It is performed so that it is fixed to the extent that it is obtained.

  The reduced diameter portion 25B provided on the distal end side of the fitting projection 25A forms a gap 37 communicating with the material holding space 36 between the inner peripheral surface 27d of the fitting recess 27A and the distal end of the fitting projection 25A. A surface 25c is formed. The reduced diameter portion 25B is a portion that protrudes in a columnar shape from the outer peripheral surface 25d via the step surface 25g at the distal end portion of the fitting protrusion 25A.

  The reduced diameter portion 25B is formed such that its cylindrical central axis coincides with the turbo rotation axis C1. Accordingly, the outer peripheral surface 25f of the reduced diameter portion 25B is spaced evenly over the entire circumference from the inner peripheral surface 27d of the fitting recess 27A that is press-fitted into the outer peripheral surface 25d of the fitting protrusion 25A. . A gap between the outer peripheral surface 25f of the reduced diameter portion 25B and the inner peripheral surface 27d of the fitting recess 27A is a gap 37 communicating with the material holding space 36.

  That is, the gap 37 is formed by the outer peripheral surface 25f of the reduced diameter portion 25B, the step surface 25g, and the inner peripheral surface 27d of the fitting concave portion 27A, and is a cylindrical space that communicates (continues) with the material holding space 36. Part. In such a configuration, as shown in FIG. 20, a press-fit portion of the fitting protrusion 25 </ b> A with respect to the fitting recess 27 </ b> A (see a range indicated by reference numeral H <b> 1 in the rotation axis direction) and a gap 37 communicating with the material holding space 36. Is formed adjacent to the rotation axis direction (left and right direction in FIG. 20).

  In the configuration in which the turbine wheel 27 is fixed to the turbine shaft 25 by press-fitting and the gap 37 communicating with the material holding space 36 is provided as in the present embodiment, the fitting protrusion 25A and the fitting protrusion 25A are fitted as described above. The silver nanopaste 40 that plays the role of a brazing material enters the gap 37 at the joint portion with the joint recess 27A. That is, as shown in FIG. 21, the silver nanopaste 40 is in a state along the inner peripheral surface 27 d that forms the material holding space 36 due to the centrifugal force accompanying the rotation of the rotating body 2 and enters the gap 37. Here, depending on the size of the gap 37, the silver nanopaste 40 enters the gap 37 by a capillary phenomenon.

  Thus, in this embodiment, the fixing by press-fitting the turbine shaft 25 and the turbine wheel 27 is reinforced by the silver nano paste 40 that enters the gap 37. That is, the gap 37 communicating with the material holding space 36 is used as a space for brazing the turbine shaft 25 and the turbine wheel 27. In the unbalance correction method of the present embodiment, the silver nano paste 40 in the material holding space 36 enters the gap 37 in step S240 in the flowcharts shown in FIGS.

  According to the imbalance correction method of the present embodiment, the steps for performing electron beam welding can be omitted in comparison with the case where the turbine shaft 25 and the turbine wheel 27 are fixed by electron beam welding. Thus, the process for correcting the unbalance of the turbocharger 1 can be simplified. In addition, in the joint portion by electron beam welding, thermal distortion may occur or the residual stress may be relatively large, but according to the imbalance correction method of the present embodiment, thermal distortion does not occur, and Since the residual stress can be reduced, the reliability at the joint portion between the turbine shaft 25 and the turbine wheel 27 is improved. Thereby, in the turbocharger 1, the vibration level is reduced and the upper limit operating rotational speed is improved (the operating efficiency is improved).

  A sixth embodiment of the present invention will be described. In the present embodiment, the surface roughness (surface roughness) of a predetermined surface among the surfaces forming the material holding space 36 is increased in comparison with other surfaces. In the present embodiment, the method of fixing the turbine shaft 25 and the turbine wheel 27 is not particularly limited, but the configuration of the fifth embodiment is cited for the fixing method and the like.

  That is, in the present embodiment, as shown in FIG. 22, the bottom surface 27 c of the fitting recess 27 A and the fitting protrusion among the wall surfaces forming the material holding space 36 provided between the turbine shaft 25 and the turbine wheel 27. The surface roughness of the tip surface 25c of 25A is made relatively large with respect to the other parts. That is, in the present embodiment, the bottom surface 27 c and the tip surface 25 c are formed as a rough surface portion 38 having a relatively large surface roughness with respect to the inner peripheral surface 27 d of the turbine wheel 27.

  As the rough surface portion 38, for example, in the step of forming the surface on which the rough surface portion 38 is formed, the finishing process for reducing the surface roughness is omitted or the finishing condition by the finishing process is roughened. A method using surface roughness such as a cut surface is exemplified. Another method includes a method of positively increasing the surface roughness by applying a surface treatment such as sandblasting.

  Thus, the surface roughness of the bottom surface 27c of the fitting recess 27A and the tip surface 25c of the fitting projection 25A is relatively increased by the rough surface portion 38, so that the wall surfaces formed as these rough surface portions 38 are The wettability with respect to the silver nanopaste 40 is improved. The following effects are obtained by improving the wettability of the bottom surface 27c and the tip surface 25c forming the material holding space 36.

  That is, as shown in FIG. 23, the corner R portion 40a generated in the relationship between the bottom surface 27c and the front end surface 25c of the silver nanopaste 40 that is in an unbalance improved state due to the improvement of the wettability of the bottom surface 27c and the front end surface 25c. growing. That is, the silver nano paste 40 is sintered and fixed in a state where the corner R portion 40a is large. The generation of the corner R portion 40 a corresponds to the formation of a so-called meniscus in the silver nanopaste 40 in the material holding space 36.

  Thus, in the configuration where the fitting protrusion 25A and the fitting recess 27A are joined in a state where the corner R portion 40a of the silver nanopaste 40 is enlarged, the rotating body 2 of the joint portion is joined. Stress concentration associated with rotation can be reduced. Thereby, the anti-centrifugal strength of the joint portion between the turbine shaft 25 and the turbine wheel 27 is improved, and the upper limit operating rotational speed of the turbocharger 1 can be improved (the operating efficiency is improved).

  Therefore, the surface roughness of the rough surface portion 38 is relatively large compared to the other portions. The corner R portion 40a is generally so large that stress concentration at the joint portion between the turbine shaft 25 and the turbine wheel 27 is reduced. This is based on the viewpoint that the surface portion to be subjected to a typical finishing process is formed relatively large. Further, the rough surface portion 38 may be formed on a wall surface other than the bottom surface 27 c of the turbine wheel 27 and the front end surface 25 c of the turbine shaft 25 among the wall surfaces forming the material holding space 36.

  That is, the rough surface portion 38 is a surface portion for enlarging the corner R portion 40a formed with respect to the silver nanopaste 40 in the material holding space 36, and thus at least the bottom surface 27c of the turbine wheel 27 and the tip surface 25c of the turbine shaft 25. What is necessary is just to form. In other words, the surface roughness of at least the bottom surface 27c and the tip surface 25c of the wall surfaces forming the material holding space 36 only needs to be relatively large. Furthermore, the rough surface portion 38 may be partially formed on each wall surface forming the material holding space 36 in accordance with the amount of the silver nano paste 40 enclosed in the material holding space 36.

  A seventh embodiment of the present invention will be described. In the present embodiment, as described above, a shape portion for guiding the silver nano paste 40 in the material holding space 36 into the gap 37 is provided on the surface where the gap 37 communicating with the material holding space 36 is formed. In the present embodiment, the method of fixing the turbine shaft 25 and the turbine wheel 27 is not particularly limited, but the configuration of the fifth embodiment is cited for the fixing method and the like.

  That is, as shown in FIG. 24, spiral grooves (hereinafter referred to as “spiral grooves”) 25C and 27C are formed on the inner peripheral surface 27d of the fitting recess 27A and the outer peripheral surface 25d of the fitting protrusion 25A. ing. Specifically, on the inner peripheral surface 27d of the fitting recess 27A, a spiral groove 27C is formed in a portion where the gap 37 is formed. Moreover, about the outer peripheral surface 25d of the fitting protrusion 25A, a spiral groove 25C is formed on the outer peripheral surface 25f of the reduced diameter portion 25B.

  The spiral grooves 25C and 27C are formed so that the silver nano paste 40 in the material holding space 36 is moved along the rotation axis direction with the inner peripheral surface 27d of the fitting recess 27A and the fitting protrusion 25A. Is led in the direction of the back side (left side in FIG. 24) of the mating surface portion with the outer peripheral surface 25d.

  The mating surface portion of the inner peripheral surface 27d and the outer peripheral surface 25d (hereinafter simply referred to as “mating surface portion”) is a portion where the fitting recess 27A and the fitting projection 25A face each other in the radial direction of the rotating body 2. is there. Therefore, in this embodiment, the facing portion between the outer peripheral surface 25d of the fitting protrusion 25A including the outer peripheral surface 25f of the reduced diameter portion 25B and a part of the inner peripheral surface 27d of the fitting concave portion 27A is the mating surface portion. .

  And about a mating surface part, in the relationship with the material holding space 36, the direction of the back | inner side among rotation-axis directions is the direction of the side in which the fitting protrusion 25A is provided, ie, the turbine shaft 25 side in this embodiment. Direction. Therefore, in the case of the configuration in which the fitting protrusion is provided on the turbine wheel 27 side, the direction on the back side of the mating surface portion in the rotation axis direction is the turbine wheel 27 side. Furthermore, in the present embodiment in which the gap 37 communicating with the material holding space 36 is formed, the direction of the back side of the mating surface portion in the rotation axis direction is the direction of the back side of the gap 37 (step surface 25g side). (Left side in FIG. 24).

  The spiral grooves 25 </ b> C and 27 </ b> C guide the silver nanopaste 40 toward the back side of the mating surface portion in the rotation axis direction by relative rotation with respect to the silver nanopaste 40 associated with the rotating body 2. The portion where the spiral grooves 25C and 27C are formed is a shape portion such as a screw surface.

  Thus, the spiral grooves 25C and 27C are formed on the inner peripheral surface 27d of the fitting recess 27A and the outer peripheral surface 25d of the fitting protrusion 25A, so that the silver nanopaste 40 in the material holding space 36 becomes the mating surface portion. It becomes easy to enter (in the gap 37). Thereby, the certainty of joining by the silver nano paste 40 which plays the role of the brazing filler metal at the joining portion between the fitting protrusion 25A and the fitting recess 27A is improved.

  In this embodiment, the spiral grooves 25C and 27C are formed on both the turbine wheel 27 (the inner peripheral surface 27d of the fitting recess 27A) and the turbine shaft 25 (the outer peripheral surface 25d of the fitting protrusion 25A). Only one of them may be used. That is, the spiral groove for guiding the silver nano paste 40 may be formed on at least one of the inner peripheral surface 27d of the fitting recess 27A and the outer peripheral surface 25d of the fitting protrusion 25A. Further, in the present embodiment, the spiral grooves 25C and 27C are on the turbine wheel 27 side (the inner peripheral surface 27d side of the fitting recess 27A), and on the turbine shaft 25 side (the outer peripheral surface of the fitting protrusion 25A). 25d side) is partially formed in the reduced diameter portion 25B, but may be formed entirely on each surface.

  In the above embodiment of the present invention, the material holding space for holding the silver nanopaste 40 is a nut (nut body 30) for fixing the impeller 26 to the turbine shaft 25, or the turbine shaft 25 and the turbine wheel. The example provided between 27 and both is shown. However, the place where the material holding space is provided is not limited to the present embodiment. That is, the material holding space for holding the silver nanopaste 40 may be provided at any location in the rotating body 2. Therefore, the material holding space may be provided in, for example, the intermediate portion of the turbine shaft 25, the inside of the turbine wheel 27, the impeller 26, and the like. Further, the number of the material holding spaces provided is not limited.

  Furthermore, a member that forms a material holding space may be provided separately as a member constituting the rotating body 2 in the rotating body 2. However, since the material holding space is provided between the nut body 30 or the turbine shaft 25 and the turbine wheel 27 as in the above-described embodiments, the existing configuration can be used when the material holding space is provided. .

  The silver nanopaste 40 put in the material holding space provided at an arbitrary place in the rotating body 2 is heated as follows, for example. That is, when the material holding space is provided in the impeller 26 located outside the housing 3, for example, a high frequency coil is used. Further, when a material holding space is provided in an intermediate portion of the turbine shaft 25 located inside the housing 3, for example, a silver nano-particle is generated by heat conduction from the end portion of the turbine shaft 25 by a high frequency coil provided outside the housing 3. The paste 40 is heated. Further, when a material holding space is provided in the turbine wheel 27, air (hot gas) supplied into the turbine housing 7 is used.

  As described above, in the configuration in which the material holding space is provided at an arbitrary place in the rotating body 2, the injection port for injecting the silver nanopaste 40 is formed in the material holding space, so that the injection port is used. The imbalance correction performed (see the second embodiment) can be applied. That is, the injection port for injecting the silver nano paste 40 is provided in the rotating body 2 corresponding to the place where the material holding space is provided.

  Further, in the embodiment of the present invention, the silver nanopaste 40 is employed as the fluid material put into the material holding space, but other materials may be used. That is, the fluid material placed in the material holding space may be any paste-like or liquid material that is cured by being heated and fixed to the wall surface forming the material holding space. The pasty or liquid state of the flowable material means that the flowable material has fluidity that can be freely deformed by moving in the material holding space as the rotating body 2 rotates.

  Examples of the fluid material that can be placed in the material holding space include metal nano pastes other than silver nano paste, such as copper nano paste in which copper (Cu) fine particles are used instead of silver fine particles, and platinum (Pt). A platinum nanopaste or the like in which is used can be employed. Other examples of fluid materials include thermosetting resins, and thermosetting resins in which metal particles (for example, silver (Ag), iron (Fe), etc.) for increasing the density are dispersed. Is mentioned.

The figure which shows the whole structure of the turbocharger which concerns on 1st embodiment of this invention. The front view which shows the nut body which concerns on 1st embodiment of this invention. Similarly side view. AA sectional drawing in FIG. BB sectional drawing in FIG. The figure which shows the graph showing the relationship between the rotation speed of a rotary body, an amplitude, and a phase. Explanatory drawing which shows the behavior of the silver nano paste accompanying rotation of a rotary body. The flowchart about the imbalance correction method which concerns on 1st embodiment of this invention. The front view which shows the nut body which concerns on 2nd embodiment of this invention. CC sectional drawing in FIG. The figure which shows the whole structure of the turbocharger which concerns on 1st embodiment of this invention. The flowchart about the imbalance correction method which concerns on 2nd embodiment of this invention. The figure which shows the whole structure of the turbocharger which concerns on 3rd embodiment of this invention. The figure which shows the structure of the fixing | fixed part of the turbine wheel with respect to the turbine shaft which concerns on 3rd embodiment of this invention. Explanatory drawing about joining of a turbine shaft and a turbine wheel. The E partial enlarged view in Fig.15 (a). The flowchart about the imbalance correction method which concerns on 3rd embodiment of this invention. The flowchart which shows another example similarly. The figure which shows the whole structure of the turbocharger which concerns on 4th embodiment of this invention. The figure which shows the structure of the fixing | fixed part of the turbine wheel with respect to the turbine shaft which concerns on 5th embodiment of this invention. The figure which similarly shows an unbalance improvement state. The figure which shows the structure of the fixing | fixed part of the turbine wheel with respect to the turbine shaft which concerns on 6th embodiment of this invention. Similarly a partially enlarged view. The figure which shows the structure of the fixing | fixed part of the turbine wheel with respect to the turbine shaft which concerns on 7th embodiment of this invention. Explanatory drawing about the conventional imbalance correction method. Similarly flow chart.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Turbocharger 2 Rotating body 21 Shaft part 22 Turbine wheel part 23 Compressor wheel part 25 Turbine shaft (shaft member)
25A Fitting protrusion 25B Reduced diameter portion 25C Spiral groove 25c Front end surface 25d Outer peripheral surface 26 Impeller 27 Turbine wheel (wheel member)
27A Fitting recess 27C Spiral groove 27c Bottom surface 27d Inner peripheral surface 30 Nut body 31 Material holding space 32 Inlet 36 Material holding space 37 Gap 38 Rough surface portion 40 Silver nano paste (fluid material)

Claims (10)

A turbocharger unbalance correction method comprising a rotating body that is rotatably supported around a predetermined rotation axis and performing supercharging by rotation of the rotating body,
The rotating body is provided with a space having a rotational shape centered on the rotating shaft, and the space is hardened by being heated and is fixed to a wall surface forming the space. With fluid material in it
A rotating step of rotating the rotating body at a predetermined number of revolutions or more in order to cause the flowable material to flow and be unevenly distributed in a position that cancels the unbalance of the rotating body in the space;
A heating step of heating the fluid material in order to cure and fix the fluid material in a state of uneven distribution in the space by the rotation step;
A turbocharger imbalance correction method characterized by: The rotating body is provided with an inlet for putting the fluid material into the space,
Before the rotation process,
The amount of unbalance of the rotating body is measured by detecting the vibration accompanying the rotation of the rotating body in a state where the rotating body in which the fluid material is not put in the space is rotated at a predetermined rotation speed. Measuring process;
An injection step of putting the fluid material in an amount corresponding to the amount of unbalance of the rotating body measured by the measurement step into the space from the injection port;
The turbocharger unbalance correction method according to claim 1, wherein: The rotating body is
A shaft portion whose axial direction is the direction of the rotating shaft, a turbine wheel portion provided on one end side in the axial direction of the shaft portion for obtaining rotational power of the rotating body, and a shaft member forming the shaft portion A compressor wheel portion that is provided on the other end side in the axial direction of the shaft portion by the impeller being fixed, and compresses intake air at the time of supercharging;
The compressor wheel portion has a fixing member for fixing the impeller to the shaft member,
The turbocharger imbalance correction method according to claim 1, wherein the space is provided in the fixing member. The rotating body is
A shaft portion whose axial direction is the direction of the rotating shaft, and a wheel member fixed to the shaft member forming the shaft portion, thereby providing rotational power of the rotating body provided on one end side in the axial direction of the shaft portion. A turbine wheel part for obtaining, and a compressor wheel part for compressing intake air that is provided at the other end side in the axial direction of the shaft part for supercharging,
The turbocharger unbalance correction method according to claim 1, wherein the space is provided between the shaft member and the wheel member. The rotating body is
A shaft portion whose axial direction is the direction of the rotating shaft, and a wheel member fixed to the shaft member forming the shaft portion, thereby providing rotational power of the rotating body provided on one end side in the axial direction of the shaft portion. A turbine wheel part for obtaining, and a compressor wheel part for compressing intake air at the time of supercharging provided on the other end side in the axial direction of the shaft part by fixing an impeller to the shaft member,
The compressor wheel portion has a fixing member for fixing the impeller to the shaft member,
3. The turbocharger imbalance correction method according to claim 1, wherein the space is provided between the fixed member and the shaft member and the wheel member. In the heating step, heating the fluid material in the space provided between the shaft member and the wheel member,
5. The method according to claim 4, wherein the air to be supplied to the turbine wheel portion for supplying the rotational power of the rotating body is performed by using a high temperature gas at a temperature high enough to cure the fluid material. The turbocharger imbalance correction method according to claim 5. A state where the wheel member is fixed to the shaft member, a fitting recess provided in one of the shaft member and the wheel member and opening to one side in the direction of the rotating shaft, the shaft member and the wheel member A fitting projection that is provided on either side and projects to the other side in the direction of the rotation shaft is fitted,
5. A bottom surface and an inner peripheral surface of the fitting recess and a tip surface of the fitting protrusion are used as a wall surface forming the space provided between the shaft member and the wheel member. The turbocharger imbalance correction method according to any one of claims 1 to 6. The fitting between the fitting recess and the fitting protrusion is press-fitting the fitting protrusion into the fitting recess,
A gap communicating with the space is formed between the fitting protrusion and the inner peripheral surface of the fitting recess on the leading end side in the protruding direction of the fitting protrusion. The turbocharger unbalance correction method according to claim 7, wherein a reduced diameter portion to be formed is provided.   Of the wall surfaces forming the space provided between the shaft member and the wheel member, the surface roughness of at least the bottom surface of the fitting recess and the tip surface of the fitting protrusion is relatively small with respect to other portions. The turbocharger imbalance correction method according to claim 7 or 8, wherein the turbocharger unbalance correction method is increased. At least one of the inner peripheral surface of the fitting recess and the outer peripheral surface of the fitting protrusion,
Along with the rotation of the rotating body in the rotating step, the fluid material in the space provided between the shaft member and the wheel member is replaced with the inner peripheral surface of the fitting recess in the direction of the rotating shaft. The turbocharger unbalance correction according to any one of claims 7 to 9, wherein a spiral groove is formed that leads in a direction toward the back side of the mating surface portion with the outer peripheral surface of the fitting protrusion. Method.

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