JP2020162285A - Method of manufacturing rotor - Google Patents

Abstract

To provide a method of manufacturing a rotor that can position a member which is dispoed on a shaft in an axial direction relative to a rotor core accurately also in the case of performing hydroforming on the shaft.SOLUTION: A method of manufacturing a rotor 100 comprises: a step (S3) of positioning a rotor core 10 in a bottom mold 210 so that an end surface 15 of the rotor core 10 and a first surface 211 of the bottom mold 210 are in contact with each other; a step (S6) of positioning a shaft 20 in the bottom mold 210 so that a second surface 212 having a fixed relative position in an axial direction to the first surface 211 and a step surface 72a of the shaft 20 are in contact with each other; and a step (S8) of fixing the shaft 20 to the rotor core 10 by hydroforming.SELECTED DRAWING: Figure 3

Description

The present invention relates to a method for manufacturing a rotor.

Conventionally, a method for manufacturing a rotor in which a shaft is fixed to an inner peripheral surface of a rotor core is known (see, for example, Patent Document 1).

The above-mentioned Patent Document 1 discloses a method for manufacturing a rotor for a motor including a hollow rotating shaft having a pipe structure and a laminated iron core in which the rotating shaft is fixed to an inner peripheral surface. In this manufacturing method, the rotating shaft is arranged inside the laminated iron core in the radial direction. Further, a molding die of the hydroforming molding machine is arranged at a position separated from the axial end face of the laminated iron core by an axial gap. Then, the rotation shaft is fixed to this molding die. As a result, a part of the rotating shafts arranged over the laminated iron core and the molding die is exposed to the outside. Then, by the hydroforming method, the portion of the rotating shaft corresponding to the laminated iron core is expanded (plastically deformed), so that the rotating shaft is fixed to the laminated iron core. In addition, the liquid is injected into the entire inside of the rotating shaft to increase the internal pressure inside the rotating shaft, so that the part of the rotating shaft exposed to the outside expands from the inner diameter of the laminated iron core to form a retaining portion. Will be done. After that, the bearing is arranged on the outer portion in the axial direction from the portion of the rotating shaft corresponding to the laminated iron core.

Japanese Unexamined Patent Publication No. 2001-268858

Here, in a rotor for a motor, it is generally necessary to accurately arrange bearings in the axial direction with respect to the laminated iron core. In other words, it is desirable that the relative positions of the laminated iron core and the bearing in the axial direction do not change as much as possible during hydroforming. However, in the method for manufacturing a rotor for a motor described in Patent Document 1, the molding die is arranged at a position separated from the axial end face of the laminated iron core in the axial direction with a gap in order to perform hydroforming. .. Therefore, the axial position of the molding die and the axial position of the laminated iron core are not fixed to each other, and the laminated iron core moves in the axial direction with respect to the forming die during hydroforming. In this case, it is considered that the relative position between the laminated iron core and the molding die may change. In this case, it is considered that the fixed position of the laminated iron core and the fixed position of the retaining portion on the rotating shaft change, and the relative position between the laminated iron core and the bearing changes. As a result, in the motor rotor described in Patent Document 1, when hydroforming is performed on the rotating shaft, when a bearing (member arranged on the shaft) is arranged on the hydroformed rotating shaft. In addition, it is considered that there is a problem that it is not easy to arrange bearings (members arranged on the shaft) with high accuracy in the axial direction with respect to the laminated iron core (rotor core).

The present invention has been made to solve the above problems, and one object of the present invention is to provide a member arranged on the shaft with respect to the rotor core even when hydroforming the shaft. It is an object of the present invention to provide a method for manufacturing a rotor that can be arranged with high accuracy in the axial direction.

In order to achieve the above object, the method for manufacturing a rotor in one aspect of the present invention is a rotor in which a shaft having a cylindrical shape is fixed to the inner peripheral surface of the shaft insertion hole of an annular rotor core having a shaft insertion hole. This is the manufacturing method of the shaft, which is located on the outer side in the radial direction of the shaft and has a stepped surface that intersects the axial direction of the shaft. The process of preparing the shaft, the end face on one side of the rotor core in the axial direction, and the mold. After the step of arranging the rotor core in the mold part and the step of preparing the shaft so that the first positioning surface of the portion contacts in the axial direction, at a position in the axial direction different from the axial position of the first positioning surface. , The process of arranging the shaft on the mold so that the second positioning surface of the mold portion whose relative position in the axial direction is fixed to the first positioning surface and the stepped surface are in axial contact, and the end surface of the rotor core. The shaft is filled with fluid and expanded by the internal pressure of the fluid while the first positioning surface is in contact with the shaft and the stepped surface is in contact with the second positioning surface. A step of fixing the shaft to the rotor core by hydroforming in which a part of the shaft is pressed against the inner peripheral surface of the insertion hole is provided.

In the method for manufacturing a rotor according to one aspect of the present invention, as described above, the relative positions of the first positioning surface and the second positioning surface in the axial direction are fixed in the mold portion. Then, in the present invention, a step of arranging the shaft on the mold portion is provided so that the second positioning surface and the stepped surface of the mold portion come into contact with each other in the axial direction. Further, in the present invention, the step of fixing the shaft to the rotor core by hydroforming while the end surface of the rotor core and the first positioning surface are in contact with each other and the stepped surface and the second positioning surface are in contact with each other. Is provided. As a result, of the first positioning surface and the second positioning surface whose relative positions in the axial direction are fixed to each other, the end surface of the rotor core is in contact with the first positioning surface, and the shaft is brought into contact with the second positioning surface. Hydroforming can be performed with the stepped surfaces in contact with each other. Therefore, it is possible to prevent the relative position between the end surface of the rotor core and the stepped surface of the shaft from changing. Then, a member (for example, a bearing member) can be arranged on the stepped surface of the shaft. As a result, even when hydroforming the shaft, the members arranged on the shaft can be accurately arranged in the axial direction with respect to the rotor core.

According to the present invention, even when hydroforming the shaft as described above, the members arranged on the shaft can be accurately arranged in the axial direction with respect to the rotor core.

It is sectional drawing along the axial direction of the rotor by one Embodiment. It is a top view which shows the structure of the rotor by one Embodiment. It is a flow chart which shows the manufacturing process of the rotor by one Embodiment. It is a top view of the rotor core by one Embodiment. It is sectional drawing for demonstrating the process of forming a shaft by one Embodiment, FIG. 5A is a figure which shows the state of the shaft after processing, and FIG. 5B is the shaft before processing (the shaft before processing (B). It is a figure which shows the state of a pipe member). It is a figure for demonstrating the process of arranging a rotor core in a lower mold by one Embodiment. It is a figure for demonstrating the process of arranging the shaft in a hole part by one Embodiment. It is a figure for demonstrating the process of arranging the shaft in the lower mold by one Embodiment. It is a figure for demonstrating the process of fixing a shaft to a rotor core by one Embodiment. It is a figure which shows the structure of the rotor and the manufacturing apparatus of a rotor by 1st modification of 1 Embodiment. It is a figure which shows the structure of the rotor and the manufacturing apparatus of the rotor by the 2nd modification of one Embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[Rotor structure of the present embodiment]
The structure of the rotor 100 according to the present embodiment will be described with reference to FIGS. 1 and 2. The rotor 100 constitutes a rotary electric machine by being combined with a stator (not shown).

In the present specification, the "axial direction and the rotation axis direction" mean the directions (see FIG. 1) along the rotation axis (reference numeral C1) (Z1 direction, Z2 direction) of the rotor 100. Further, "upward" means the Z1 direction, and "downward" means the Z2 direction. Further, the “diameter inside” means a direction (R1 direction) toward the rotation axis C1 of the rotor 100. Further, the "radial outer side" means a direction (R2 direction) toward the outer side of the rotor 100. Further, the "circumferential direction" means the circumferential direction (A1 direction, A2 direction) of the rotor 100 as shown in FIG.

As shown in FIG. 1, the rotor 100 includes a rotor core 10, a shaft 20, and bearing members 31 and 32. The rotor core 10 is formed by laminating a plurality of electromagnetic steel plates 11 having holes 11a along the axial direction. For example, the electromagnetic steel plate 11 is made of a silicon steel plate. Further, the rotor core 10 has a cylindrical shape whose central axis coincides with the rotation axis C1. Further, the inner peripheral surface 12 of the rotor core 10 (hole portion 11a) is formed in a substantially uniform shape along the axial direction. Further, the outer peripheral surface 13 of the rotor core 10 is formed in a substantially uniform shape along the axial direction. The hole portion 11a is an example of a “shaft insertion hole” within the scope of the claims.

The shaft 20 has a cylindrical shape whose central axis coincides with the rotation axis C1. For example, the shaft 20 is made of carbon steel. Further, the shaft 20 is fixed to the inner peripheral surface 12 of the rotor core 10. The shaft 20 includes a first portion 40, a second portion 50, and a third portion 60. Further, the first portion 40, the second portion 50, and the third portion 60 each have a cylindrical shape. For example, the first portion 40, the second portion 50, and the third portion 60 all have an inner diameter D1. That is, the inner peripheral surface 42 of the first portion 40, the inner peripheral surface 52 of the second portion 50, and the inner peripheral surface 62 of the third portion 60 are formed substantially flush with each other in the Z direction.

The first portion 40 is a portion of the shaft 20 arranged on the inner peripheral surface 12 of the rotor core 10 at the central portion in the axial direction. Specifically, the outer peripheral surface 41 of the first portion 40 and the inner peripheral surface 12 of the rotor core 10 are in contact with each other. In the present embodiment, the first portion 40 is pressure-welded to the inner peripheral surface 12 of the hole portion 11a by using hydroforming. The outer diameter of the first portion 40 is D11, and the thickness is t1.

The second portion 50 is a portion of the shaft 20 on the Z1 direction side with respect to the first portion 40. Further, the third portion 60 is a portion of the shaft 20 on the Z2 direction side with respect to the first portion 40. The second portion 50 is a portion where the bearing member 31 is arranged. Further, the third portion 60 is a portion where the bearing member 32 is arranged.

The outer diameters of the second portion 50 and the third portion 60 are both D12, and the thickness is both t2. Here, the outer diameter D12 is smaller than the outer diameter D11 of the first portion 40. Further, the thickness t2 is smaller than the thickness t1 of the first portion 40.

Further, a step portion 71 is formed between the outer peripheral surface 41 of the first portion 40 and the outer peripheral surface 51 of the second portion 50. Specifically, the stepped portion 71 has a shape that is recessed inward in the radial direction from the outer peripheral surface 41 of the first portion 40 toward the outer peripheral surface 51 of the second portion 50. The stepped portion 71 includes a stepped surface 71a parallel to the direction orthogonal to the axial direction. As shown in FIG. 2, the stepped surface 71a is formed so as to face the Z1 direction (the Z1 direction side is the surface).

Further, a step portion 72 is formed between the outer peripheral surface 41 of the first portion 40 and the outer peripheral surface 61 of the third portion 60. Further, the step portion 72 has a shape of being recessed inward in the radial direction from the outer peripheral surface 41 of the first portion 40 toward the outer peripheral surface 61 of the third portion 60. The step portion 72 includes a step surface 72a parallel to the direction orthogonal to the axial direction. Further, the stepped surface 72a is formed so as to face the Z2 direction side.

The bearing member 31 surrounds the outer peripheral surface 51 of the second portion 50 in the circumferential direction from the outside in the radial direction, and is arranged so as to come into contact with the stepped surface 71a of the stepped portion 71. Further, the bearing member 32 is arranged so as to surround the outer peripheral surface 61 of the third portion 60 in the circumferential direction from the outside in the radial direction and to contact the stepped surface 72a of the stepped portion 72. The bearing members 31 and 32 rotatably support the shaft 20 and the rotor core 10 about the center of the rotation axis C1.

Further, the stepped surface 71a is arranged at a distance in the axial direction from the end surface 14 on the Z1 direction side of the rotor core 10. For example, the axial distance between the stepped surface 71a and the end surface 14 is D21. That is, the axial distance between the bearing member 31 and the end face 14 is D21. Further, the stepped surface 72a is arranged at a distance in the axial direction from the end surface 15 on the Z2 direction side of the rotor core 10. For example, the axial distance between the stepped surface 72a and the end surface 15 is D22. That is, the axial distance between the bearing member 32 and the end face 15 is D22. The end face 15 is an example of the "one end face in the axial direction of the rotor core" and the "lower end face of the rotor core" in the claims.

[Manufacturing method of rotor of this embodiment]
Next, a method of manufacturing the rotor 100 according to the present embodiment will be described with reference to FIGS. 3 to 9. FIG. 3 shows a flowchart of the manufacturing process of the rotor 100.

First, in step S1, the rotor core 10 is prepared (formed). Specifically, as shown in FIG. 4, a plurality of annular electromagnetic steel sheets 11 having holes 11a are punched out from the strip-shaped electrical steel sheets in a progressive press working apparatus (not shown), and a plurality of annular electromagnetic steel sheets 11 are punched out. The electromagnetic steel sheets 11 are laminated along the direction of the rotation axis. As a result, the rotor core 10 having an annular shape (cylindrical shape) is formed. Further, in the present embodiment, the rotor core 10 has a shape in which a plurality of electromagnetic steel plates 11 that are the same as each other are laminated, and the inner peripheral surface 12 of the hole portion 11a is flush with each other along the rotation axis direction. It is formed.

In step S2, the shaft 20 is prepared. Specifically, as shown in FIG. 5A, a shaft 20 is prepared, which is located on the radial outer side of the shaft 20 and has stepped surfaces 71a and 72a intersecting the axial direction of the shaft 20. .. Specifically, a first portion 40 having an outer diameter D31, a second portion 50 having an outer diameter D12 provided on the Z1 direction side of the first portion 40, and a Z2 direction side of the first portion 40 are provided. A shaft 20 is formed that includes a third portion 60 having an outer diameter D12.

For example, as shown in FIG. 5B, a pipe member 20a having an outer diameter D31 and a thickness t1 is prepared. Then, the portion corresponding to the outer peripheral surface 51 of the second portion 50 of the pipe member 20a and the portion corresponding to the outer peripheral surface 61 of the third portion 60 are cut, so that the second portion having the outer diameter D12 and the thickness t2. A third portion 60 having 50 and an outer diameter D12 and a thickness t2 is formed. Further, a stepped portion 71 having a stepped surface 71a is formed between the outer peripheral surface 41 of the first portion 40 and the outer peripheral surface 51 of the second portion 50. Further, a stepped portion 72 having a stepped surface 72a is formed between the outer peripheral surface 41 of the first portion 40 and the outer peripheral surface 61 of the third portion 60.

Then, in the present embodiment, the stepped surface 71a connects the outer peripheral surface 41 of the first portion 40 and the outer peripheral surface 51 of the second portion 50, and is formed as a surface orthogonal to the Z direction. Further, the stepped surface 71a is formed as a surface facing the Z1 direction. Further, the stepped surface 72a connects the outer peripheral surface 41 of the first portion 40 and the outer peripheral surface 61 of the third portion 60, and is formed as a surface orthogonal to the Z direction. Further, the stepped surface 72a is formed as a surface facing the Z2 direction. That is, the stepped surface 71a is formed so as to be substantially orthogonal to the outer peripheral surface 51 of the second portion 50. Further, the stepped surface 72a is formed so as to be substantially orthogonal to the outer peripheral surface 61 of the third portion 60.

In step S3, the rotor core 10 is arranged in the lower mold 210 of the hydroforming machine 200. Specifically, first, as shown in FIG. 6, a lower mold 210 having an upper surface, a first surface 211, and an upper surface, a second surface 212, is prepared. Further, a hole 213 in which a lifter 220, which will be described later, is arranged is provided inside the lower mold 210 in the radial direction. The lower mold 210 is an example of a "mold portion" in the claims. Further, the first surface 211 is an example of the "first positioning surface" in the claims. Further, the second surface 212 is an example of the "second positioning surface" in the claims.

In the present embodiment, the first surface 211 and the second surface 212 in which the relative position in the axial direction is fixed to the first surface 211 at the axial position P2 different from the axial position P1 of the first surface 211. The lower mold 210 to be held is prepared. Specifically, the first surface 211 is formed in a portion of the lower mold 210 on the upper side of the second surface 212. For example, the axial distance between the first surface 211 and the second surface 212 is set to be substantially the same as the axial distance D22 between the end surface 15 of the rotor core 10 and the bearing member 32. Further, the second surface 212 is formed radially inside the first surface 211. Further, in the lower mold 210, the portion 210a having the first surface 211 and the portion 210b having the second surface 212 are integrally formed by a single member (mold member).

Then, the rotor core 10 is arranged on the lower mold 210 so that the end surface 15 on the Z2 direction side of the rotor core 10 and the first surface 211 which is the upper surface of the lower mold 210 are in axial contact with each other. Specifically, the rotor core 10 in a state in which a plurality of annular electromagnetic steel sheets 11 are laminated is placed on the first surface 211.

In step S4, the shaft 20 is arranged on the lifter 220. More specifically, as shown in FIG. 6, a columnar lifter 220 arranged in the radial inner hole 213 of the lower mold 210 is prepared. Then, the shaft 20 is placed on the lifter 220 so that the lower end surface 21 of the shaft 20 comes into contact with the upper surface 221 of the lifter 220. Further, the lifter 220 is configured to be movable in the vertical direction separately from the lower mold 210. For example, the shaft 20 is placed on the surface 221 of the lifter 220 in a state where the axial position P3 of the surface 221 of the lifter 220 is located above the axial position P2 of the second surface 212 of the lower mold 210. To.

In step S5, the pressing member 230 is arranged on the shaft 20. Specifically, as shown in FIG. 6, a hole 231 in which a punch member 240 described later is arranged is provided inside in the radial direction, and a pressing member configured to be movable in the vertical direction separately from the punch member 240. 230 is arranged. Here, the pressing member 230 functions as an upper mold when performing hydroforming. Further, the pressing member 230 is provided with a third surface 232 and a fourth surface 233. The axial position P4 where the third surface 232 is provided is above the axial position P5 where the fourth surface 233 is provided. Further, the third surface 232 is provided on the inner side in the radial direction with respect to the fourth surface 233.

As shown in FIG. 7, the pressing member 230 is arranged above the shaft 20 so that the stepped surface 71a of the shaft 20 and the third surface 232 of the pressing member 230 are in axial contact with each other. Specifically, the stepped surface 71a and the third surface 232 are in surface contact with each other. As a result, the shaft 20 is axially sandwiched (held) by the lower mold 210 and the pressing member 230.

In step S6, the shaft 20 is arranged on the lower mold 210. Further, the shaft 20 is arranged in the hole portion 11a of the rotor core 10. Specifically, as shown in FIG. 7, the lifter 220 and the pressing member 230 are sandwiched (held) in the axial direction by the lower mold 210 and the pressing member 230, and the lifter 220 and the pressing member 230 are held. The members 230 are both moved downward. As a result, the shaft 20 is arranged on the lower mold 210. Specifically, the lifter 220 and the pressing member 230 are moved downward so that the second surface 212 of the lower mold 210 and the stepped surface 72a come into contact with each other (until they come into contact with each other), and the shaft 20 is arranged on the lower mold 210. ..

Further, in the present embodiment, the shaft 20 is in contact with the lower mold 210 in a state where the end surface 21 of the shaft 20 and the lower mold 210 are not in contact with each other and the second surface 212 of the lower mold 210 is in contact with the stepped surface 72a. Be placed. That is, the third portion 60 of the shaft 20 is arranged radially inside the lower mold 210. As a result, the end surface 14 of the rotor core 10 is positioned at the axial position P1 by the first surface 211 of the lower mold 210, and the stepped surface 72a of the shaft 20 is axially positioned by the second surface 212 of the lower mold 210. It is in a state of being positioned at the position P2 of. In other words, the shaft 20 is arranged on the lower mold 210 so that the second surface 212 provided on the Z2 direction side of the first surface 211 of the lower mold 210 and the stepped surface 72a come into contact with each other. Specifically, the stepped surface 72a and the second surface 212 are in surface contact with each other.

In step S7, the punch member 240 is arranged on the shaft 20. Specifically, as shown in FIG. 8, the punch member 240 is arranged above the shaft 20 and inside the pressing member 230 in the radial direction. Then, as shown in FIG. 9, the end surface 22 of the shaft 20 on the Z1 direction side is brought into contact with the lower surface 241 of the punch member 240.

In step S8, the shaft 20 is fixed to the rotor core 10. Specifically, the shaft 20 is fixed to the rotor core 10 by hydroforming. In the present embodiment, the punch member 240 presses the end face 22 on the upper side of the shaft 20, and the lifter 220 presses the end face 22, so that the inside of the shaft 20 is sealed. Further, the end surface 15 of the rotor core 10 and the first surface 211 are in contact with each other, and the stepped surface 72a and the second surface 212 are in contact with each other. Further, the end surface 15 of the rotor core 10 and the first surface 211 are in surface contact with each other, and the stepped surface 72a and the second surface 212 are in surface contact with each other. In this state, the shaft 20 is fixed to the rotor core 10 by hydroforming.

Here, the lifter 220 and the punch member 240 function as a seal type when hydroforming. Specifically, the punch member 240 presses the upper end surface 22 of the shaft 20, and the lifter 220 presses the lower end surface 21 of the shaft 20, thereby sealing the inside of the shaft 20.

Then, the hydroforming machine 200 injects the fluid L into the inside of the shaft 20 (inner peripheral surfaces 42, 52, and 62 sides), and pressurizes the inside of the shaft 20. The internal pressure P of the shaft 20 is, for example, several hundred MPa. The internal pressure P is a pressure that allows the first portion 40 of the shaft 20 to be plastically deformed and a pressure that elastically deforms the rotor core 10. In other words, the internal pressure P is a pressure capable of fixing the shaft 20 to the rotor core 10. As a result, the outer diameter D31 of the first portion 40 is expanded to the outer diameter D11, and the gap between the inner peripheral surface 12 of the rotor core 10 and the outer peripheral surface 41 of the first portion 40 is filled.

Then, when the first portion 40 presses the rotor core 10 radially outward, the rotor core 10 is also elastically deformed so as to expand radially outward, and the first portion 40 expands radially outward. Plastic deformation. After that, the fluid inside the shaft 20 is removed, the rotor core 10 contracts inward in the radial direction, and the rotor core 10 returns to the shape before elastic deformation. Further, the second portion 50 and the third portion 60 also shrink inward in the radial direction, and the second portion 50 and the third portion 60 return to the shape before elastic deformation. Then, the plastically deformed first portion 40 is in a state of being pressure-welded (tightened-fitted state) by the rotor core 10 that has shrunk inward in the radial direction. As a result, as shown in FIG. 1, the shaft 20 is fixed to the rotor core 10. After that, the rotor core 10 and the shaft 20 are removed from the hydroforming machine 200.

In step S9, the bearing members 31 and 32 are arranged on the shaft 20 as shown in FIG. Specifically, the bearing member 31 is arranged on the shaft 20 so that the bearing member 31 comes into contact with the stepped surface 71a of the stepped portion 71. Further, the bearing member 32 is arranged on the shaft 20 so that the bearing member 32 comes into contact with the stepped surface 72a of the stepped portion 72. Further, the bearing member 31 is arranged so as to surround the outer peripheral surface 51 of the second portion 50, and the bearing member 32 is arranged so as to surround the outer peripheral surface 61 of the third portion 60. Specifically, the bearing member 31 is arranged so as to come into contact with the stepped surface 71a of the stepped portion 71, and the bearing member 32 is arranged so as to come into contact with the stepped surface 72a of the stepped portion 72. As a result, the rotor 100 is manufactured. After that, the rotary electric machine is manufactured by arranging the stator on the radial outer side of the rotor 100.

[Effect of this embodiment]
In this embodiment, the following effects can be obtained.

In the present embodiment, as described above, the relative positions (P1, P2) in the axial direction of the first positioning surface (211) and the second positioning surface (212) are fixed in the mold portion (210). Then, in the present embodiment, the step of arranging the shaft (20) on the mold portion (210) so that the second positioning surface (212) of the mold portion (210) and the stepped surface (72a) are in axial contact with each other. (S6) is provided. Further, in the present embodiment, the end surface (15) of the rotor core (10) and the first positioning surface (211) are in contact with each other, and the stepped surface (72a) and the second positioning surface (212) are in contact with each other. A step (S8) of fixing the shaft (20) to the rotor core (10) by hydroforming in the contacted state is provided. As a result, of the first positioning surface (211) and the second positioning surface (212) in which the relative positions (P1, P2) in the axial direction are fixed to each other, the rotor core (10) is attached to the first positioning surface (211). Hydroforming can be performed with the end surface (15) in contact with the second positioning surface (212) and with the stepped surface (72a) of the shaft (20) in contact with the second positioning surface (212). Therefore, it is possible to prevent the relative positions (P1, P2) of the end surface (15) of the rotor core (10) and the stepped surface (72a) of the shaft (20) from changing. Then, a member (32) (for example, a bearing member (32)) can be arranged on the stepped surface (72a) of the shaft (20). As a result, even when hydroforming the shaft (20), the member (32) arranged on the shaft (20) can be accurately arranged in the axial direction with respect to the rotor core (10).

In the present embodiment, as described above, after the step (S8) of fixing the shaft (20) to the rotor core (10), the bearing member (32) comes into contact with the stepped surface (72a) so that the bearing member (32) comes into contact with the bearing member (32). ) Is further provided in the step (S9) of arranging the shaft (20). With this configuration, it is possible to prevent the relative positions (P1, P2) of the end surface (15) of the rotor core (10) and the stepped surface (72a) of the shaft (20) from changing. With respect to 10), the bearing member (32) arranged on the stepped surface (72a) can be arranged with high accuracy in the axial direction.

In the present embodiment, as described above, in the step (S2) of preparing the shaft (20), the shaft (20) on which the stepped surface (72a) orthogonal to the axial direction of the shaft (20) is formed is prepared. This is the step (S2). With this configuration, the shaft (20) is brought into surface contact with the mold portion (210) by bringing the stepped surface (72a) orthogonal to the axial direction of the shaft (20) into surface contact with the second positioning surface (212). It is possible to effectively prevent the position (P2) in the axial direction of the above from shifting. As a result, the relative position (P1) between the axial position (P2) of the shaft (20) and the axial position (P1) of the rotor core (10) in contact with the first positioning surface (211) of the mold portion (210) ( It is possible to effectively prevent P1 and P2) from shifting. As a result, it is possible to further prevent the relative positions (P1, P2) of the end surface (15) of the rotor core (10) and the stepped surface (72a) of the shaft (20) from changing.

In the present embodiment, as described above, the step (S6) of arranging the shaft (20) includes a portion (210a) having a first positioning surface (211) and a portion (210b) having a second positioning surface (212). The shaft (20) is attached to the mold portion (210) so that the second positioning surface (212) of the mold portion (210) integrally formed by a single member and the stepped surface (72a) are in contact with each other. It is a step (S6) of arranging in. Here, when the portion (210a) having the first positioning surface (211) and the portion (210b) having the second positioning surface (212) are formed by separate members, the configuration of the mold portion (210) Becomes complicated. On the other hand, in the present embodiment, as described above, the portion (210a) having the first positioning surface (211) and the portion (210b) having the second positioning surface (212) are integrated by a single member. The shaft (20) is arranged on the mold portion (210) so that the second positioning surface (212) of the mold portion (210) formed therein and the stepped surface (72a) are in contact with each other. As a result, the mold portion (210) can be formed by a single member, so that the member forming the portion (210a) having the first positioning surface (211) and the portion having the second positioning surface (212). Unlike the case where the members constituting (210b) are configured as separate members from each other, it is possible to prevent the configuration of the rotor manufacturing apparatus from becoming complicated.

In the present embodiment, as described above, the step (S3) of arranging the rotor core (10) is performed on the lower end surface (15) of the rotor core (10) and the mold portion (210) as the lower mold (210). This is a step (S3) of arranging the rotor core (10) on the mold portion (210) so as to come into contact with the first positioning surface (211) which is the upper surface. With this configuration, by placing the rotor core (10) on the lower mold (210), the lower end face (15) of the rotor core (10) is moved to the lower mold (210) by the gravity applied to the rotor core (10). ) Can be easily brought into contact with the first positioning surface (211). As a result, it is not necessary to provide the rotor (100) manufacturing apparatus (200) with a configuration for keeping the end surface (15) of the rotor core (10) in contact with the first positioning surface (211). It is possible to prevent the configuration of the manufacturing apparatus (200) of 100) from becoming complicated.

In the present embodiment, as described above, in the step (S6) of arranging the shaft (20), the lower end surface (21) of the shaft (20) is arranged radially inside the mold portion (210). With the shaft (20) mounted on the lifter (220) so as to come into contact with the upper surface (221) of the lifter (220), the lifter (220) is moved downward to form a mold portion. This is a step (S6) of arranging the shaft (20) on the mold portion (210) so that the second positioning surface (212) of (210) and the stepped surface (72a) are in contact with each other. With this configuration, the shaft (20) can be moved in the vertical direction by the lifter (220) arranged radially inside the mold portion (210), so that the lower mold (210) (mold portion (210)) can be moved. Even if the rotor core (10) is already arranged in 210)), the shaft (20) can be easily inserted into the shaft (20) insertion hole (diameterally inside the rotor core (10)) of the rotor core (10). Can be done.

In the present embodiment, as described above, in the step (S6) of arranging the shaft (20), the shaft (20) is axially oriented by the holding member and the lifter (220) arranged on the upper side of the shaft (20). The lifter (220) and the pressing member (230) are both moved downward while being sandwiched between the two, so that the second positioning surface (212) and the stepped surface (72a) of the mold portion (210) come into contact with each other. As described above, it is a step (S6) of arranging the shaft (20) on the mold portion (210). With this configuration, the shaft (20) is moved in the axial direction while the shaft (20) is held by the pressing member (230) and the lifter (220), and the shaft (20) is moved to the mold portion (210). ) Can be placed.

In the present embodiment, as described above, in the step (S8) of fixing the shaft (20) to the rotor core (10), the upper end surface (22) of the shaft (20) is pressed by the punch member (240). At the same time, the lower end face (21) of the shaft (20) is pressed by the lifter (220) so that the inside of the shaft (20) is sealed and the end face (15) of the rotor core (10) is sealed. The shaft (20) is brought into contact with the rotor core (10) by hydroforming in a state where the first positioning surface (211) is in contact with the step surface (72a) and the second positioning surface (212) is in contact with each other. ) Is the step (S8). With this configuration, the lifter (220) for arranging the shaft (20) in the shaft insertion hole (11a) of the rotor core (10) can be used as a seal member, so that the lifter (220) and the punch member can be used. Unlike the case where the sealing member is provided separately from (240), it is possible to prevent the number of components of the rotor (100) manufacturing apparatus (200) from increasing.

In the present embodiment, as described above, in the step (S6) of arranging the shaft (20), the end face (21) on one side in the axial direction of the shaft (20) and the mold portion (210) do not come into contact with each other. This is a step (S6) of arranging the shaft (20) on the mold portion (210) in a state where the second positioning surface (212) of the mold portion (210) is in contact with the stepped surface (72a). Here, when the axial length from one end surface of the shaft in the axial direction to the stepped surface is relatively large due to a dimensional error, and the axial end surface of the shaft comes into contact with the mold portion, It is considered that the stepped surface and the second positioning surface may be separated from each other, making it difficult to bring the second positioning surface into contact with the stepped surface. As a result, it is considered difficult to fix the relative position between the stepped surface of the shaft and the end surface of the rotor core. On the other hand, in the present embodiment, as described above, the end surface (21) on one side in the axial direction of the shaft (20) and the mold portion (210) are not in contact with each other, and the stepped surface (72a). The shaft (20) is arranged on the mold portion (210) in a state where the second positioning surface (212) of the mold portion (210) is in contact with the mold portion (210). As a result, the end surface (21) on one side of the shaft (20) in the axial direction and the mold portion (210) do not come into contact with each other, so that the stepped surface (72a) has a second positioning surface (212) of the mold portion (210). Can be contacted more reliably. As a result, it is possible to more reliably prevent the relative positions (P1, P2) of the stepped surface (72a) of the shaft (20) and the end surface (15) of the rotor core (10) from changing.

In the present embodiment, as described above, the step (S6) of arranging the shaft (20) is the second positioning provided on one side in the axial direction from the first positioning surface (211) of the mold portion (210). This is a step (S6) of arranging the shaft (20) on the mold portion (210) so that the surface (212) and the stepped surface (72a) are in contact with each other. With this configuration, a stepped surface (72a) is formed on one side in the axial direction with respect to the rotor core (10) in a state where the shaft (20) is fixed to the rotor core (10). Therefore, even after the shaft (20) is fixed to the rotor core (10), a member (bearing member (32) or the like) is placed on the stepped surface (72a) formed on one side in the axial direction from the rotor core (10). It can be easily arranged.

[Modification example]
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

(First modification)
For example, in the above embodiment, an example is shown in which the axial position P2 of the second surface 212 is provided below the axial position P1 of the first surface 211 of the lower mold 210. Not limited. For example, as in the manufacturing apparatus 400 of the rotor 300 of the first modification shown in FIG. 10, the axial position of the second surface 412 is above the axial position P11 of the first surface 411 of the lower mold 410. P12 may be provided. The first surface 411 is an example of the "first positioning surface" in the claims. Further, the second surface 412 is an example of the "second positioning surface" in the claims.

Here, as shown in FIG. 10, the rotor 300 according to the first modification includes a shaft 320. In the shaft 320, a stepped surface 372a is formed at an axial position P12 on the upper side of the axial position P11 of the lower end surface 15 of the rotor core 10. The manufacturing apparatus 400 includes a lifter 220 and a lower mold 410. The lower mold 410 includes a first surface 411 provided at the axial position P11 and a second surface 412 provided at the axial position P12. When manufacturing the rotor 300, the first surface 411 is arranged so as to be in contact with the end surface 15 of the rotor core 10. The second surface 412 is arranged so as to come into contact with the step surface 372a. Further, the upper surface 221 of the lifter 220 comes into contact with the lower end surface 321 of the shaft 320.

(Second modification)
Further, in the above embodiment, an example is shown in which the thickness t1 of the first portion 40 is made larger than the thickness t2 of the third portion 60, but the present invention is not limited to this. For example, the thickness t11 of the first portion 540 may be smaller than the thickness t12 of the third portion 360, as in the rotor 500 of the second modification shown in FIG.

Further, in the above embodiment, an example of forming a shaft 20 in which the first portion 40 and the third portion 60 are directly connected is shown, but the present invention is not limited to this. For example, as in the rotor 500 of the second modification shown in FIG. 11, a connecting portion 572 extending so as to be inclined with respect to the axial direction may be provided between the first portion 540 and the third portion 560. In this case, the lower end surface of the connecting portion 572 is configured as the stepped surface 572a. Further, the manufacturing apparatus 600 of the rotor 500 includes a lower mold 610 and a lifter 620. The lower mold 610 includes a first surface 611 that contacts the end surface 15 of the rotor core 10 and a second surface 612 that contacts the stepped surface 572a. The upper surface 621 of the lifter 620 contacts the lower end surface 521 of the shaft 520. The first surface 611 is an example of the "first positioning surface" in the claims. Further, the second surface 612 is an example of the "second positioning surface" in the claims.

(Other variants)
Further, in the above embodiment, an example is shown in which the mold portion having the first surface 211 and the second surface 212 is configured as the lower mold 210, but the present invention is not limited to this. For example, when the rotation axis of the shaft 20 is arranged along the horizontal direction, the mold portion having the first surface 211 and the second surface 212 may be configured as the mold portion on one side in the horizontal direction. ..

Further, in the above embodiment, an example in which the bearing member 32 is arranged on the stepped surface 72a is shown, but the present invention is not limited to this. For example, a resolver may be provided on the stepped surface 72a.

Further, in the above embodiment, an example in which the stepped surface 72a is configured as a surface orthogonal to the axial direction is shown, but the present invention is not limited to this. For example, the stepped surface may be configured as a surface that intersects an obtuse angle or an acute angle in the axial direction.

Further, in the above embodiment, an example in which the lower mold 210 having the first surface 211 and the second surface 212 is composed of a single member is shown, but the present invention is not limited to this. For example, if the positions of the first surface, the second surface, and the axial direction are fixed, the portion having the first surface and the portion having the second surface may be composed of members that are separate from each other.

Further, in the above embodiment, an example is shown in which the rotor core is formed so that the inner peripheral surface of the hole portion of the rotor core is flush with each other along the axial direction, but the present invention is not limited to this. For example, an uneven shape (key) may be formed on the inner peripheral surface of the hole of the rotor core.

10 Rotor core 11a hole (shaft insertion hole)
12 Inner peripheral surface 15 End surface (one end surface in the axial direction of the rotor core)
20, 320, 520 Shaft 21, 321, 521 End face (lower end face of shaft)
22 End face (end face on the upper side of the shaft) 31, 32 Bearing member 40 First part (part of the shaft) 72 Steps 72a, 372a, 572a Steps 100, 300, 500 Rotor 210, 410, 610 Lower mold (mold) Department)
210a part (part having the first positioning surface)
210b part (part having a second positioning surface)
211, 411, 611 First surface (first positioning surface)
212, 412, 612 2nd surface (2nd positioning surface)
220, 620 Lifter 221 surface (upper surface of lifter)
230 Pressing member 240 Punch member 621 Top surface (upper surface of lifter)

Claims (10)

A method for manufacturing a rotor, wherein a shaft having a cylindrical shape is fixed to the inner peripheral surface of the shaft insertion hole of an annular rotor core having a shaft insertion hole.
A step of preparing the shaft, which is located on the outer side in the radial direction of the shaft and has a stepped surface that intersects the axial direction of the shaft.
A step of arranging the rotor core in the mold portion so that one end surface of the rotor core in the axial direction and a first positioning surface of the mold portion are in contact with each other in the axial direction.
After the step of preparing the shaft, the first of the mold portion in which the relative position between the first positioning surface and the axial direction is fixed at the axial position different from the axial position of the first positioning surface. 2. A step of arranging the shaft in the mold portion so that the positioning surface and the stepped surface come into contact with each other in the axial direction.
The inside of the shaft is filled with a fluid and the fluid is in contact with the end surface of the rotor core and the first positioning surface, and with the stepped surface and the second positioning surface in contact with each other. Manufacture of a rotor comprising a step of fixing the shaft to the rotor core by hydroforming in which a part of the shaft is pressed against the inner peripheral surface of the shaft insertion hole by expanding the shaft by the internal pressure of the shaft. Method. The method for manufacturing a rotor according to claim 1, further comprising a step of arranging the bearing member on the shaft so that the bearing member comes into contact with the stepped surface after the step of fixing the shaft to the rotor core. The method for manufacturing a rotor according to claim 1 or 2, wherein the step of preparing the shaft is a step of preparing the shaft in which the stepped surface orthogonal to the axial direction of the shaft is formed. In the step of arranging the shaft, the second positioning surface of the mold portion in which the portion having the first positioning surface and the portion having the second positioning surface are integrally formed by a single member, and the said The method for manufacturing a rotor according to any one of claims 1 to 3, which is a step of arranging the shaft in the mold portion so as to come into contact with the stepped surface. In the step of arranging the rotor core, the rotor core is placed on the mold portion so that the end surface on the lower side of the rotor core and the first positioning surface which is the upper surface of the mold portion as a lower mold come into contact with each other. The method for manufacturing a rotor according to any one of claims 1 to 4, which is a step of arranging. In the step of arranging the shaft, the shaft is placed on the lifter so that the lower end surface of the shaft comes into contact with the upper surface of the lifter arranged radially inward from the mold portion. 5. The step of arranging the shaft on the mold portion so that the second positioning surface of the mold portion and the stepped surface come into contact with each other by moving the lifter downward in this state. The method for manufacturing a rotor described in 1. In the step of arranging the shaft, the lifter and the holding member are both moved downward while the shaft is sandwiched in the axial direction by the holding member arranged on the upper side of the shaft and the lifter. The method for manufacturing a rotor according to claim 6, wherein the shaft is arranged in the mold portion so that the second positioning surface of the mold portion and the stepped surface come into contact with each other. In the step of fixing the shaft to the rotor core, the inside of the shaft is sealed by pressing the upper end surface of the shaft by the punch member and pressing the lower end surface of the shaft by the lifter. By the hydroforming, in a state where the end surface of the rotor core and the first positioning surface are in contact with each other, and in a state where the stepped surface and the second positioning surface are in contact with each other. The method for manufacturing a rotor according to claim 6 or 7, which is a step of fixing the shaft to the rotor core. In the step of arranging the shaft, the end surface on one side of the shaft in the axial direction is not in contact with the mold portion, and the second positioning surface of the mold portion is in contact with the stepped surface. The method for manufacturing a rotor according to any one of claims 1 to 8, which is a step of arranging the shaft in the mold portion. In the step of arranging the shaft, the shaft is brought into contact with the second positioning surface provided on one side in the axial direction from the first positioning surface of the mold portion and the stepped surface. The method for manufacturing a rotor according to any one of claims 1 to 9, which is a step of arranging the rotor in a mold portion.

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