JP2006026681A - Manufacturing method for coil having irregular section - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a coil having irregular sections for preventing the deformation of the coil caused by the spring-back without providing any special step. <P>SOLUTION: The spring-back of a wire 3 occurring when winding the wire 3 in a substantially spiral shape is reduced by adjusting the degree of deformation of the wire 3 occurring when pressing a coil connection body 21 formed by winding the wire 3 around a core 31 in a substantially spiral shape. The maximum working rate of the thickness by pressing each part of the wire 3 is set so as to be not less than a predetermined reference value. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a modified cross-sectional coil suitable for a motor of a hybrid vehicle or an electric vehicle.

  In order to increase the efficiency and output of drive motors for hybrid vehicles and electric vehicles, it is effective to improve the space factor of the motor coils. As a method of improving the space factor, a method of changing the cross-sectional shape of the wire according to the position on the winding path of the coil has been proposed, whereas the conventional wire having a constant cross-sectional shape is wound.

  FIG. 12 is a perspective view of a coil to which the method for manufacturing a modified cross-section coil according to the present invention is applied. As shown in FIG. 12, this coil 1 has a substantially truncated cone-shaped appearance, and the cross-sectional shape of the wire 3 is from the end on the small diameter side (the lower side in FIG. 12) to the large diameter side (see FIG. 12). 12 gradually changes toward a flat end toward the upper end. At both ends of the coil 1, lead portions 5 and 7 for electrical connection are provided. Note that the coil 1 shown in FIG. 12 has an external appearance (substantially truncated quadrangular pyramid shape) in which a substantially quadrangular pyramid head is cut off.

  As a manufacturing method of such a coil 1, as shown in FIG. 13, a wire 3 is wound around a core 9 in a substantially spiral shape to form a substantially columnar intermediate coil body 11, and the intermediate coil body 11 is There has been proposed a method of setting in a mold 13 and press-molding in the axial direction.

  However, in the method of simply press-molding the intermediate coil body 11 as described above, the shape of the coil 1 is deformed by the springback remaining in each bent portion of the coil 1 when the coil 1 is removed from the core material 9. Therefore, there is a problem that an extra process (for example, a process of unwinding and annealing the coil 1) for correcting the shape of the coil 1 is required.

  Therefore, the problem to be solved by the present invention is to provide a method of manufacturing a modified cross-section coil that can prevent the deformation of the coil due to the spring back without providing a special process.

  In order to solve the above-mentioned problem, in the invention of claim 1, a modified cross-sectional coil for manufacturing a coil having a modified cross-section by press-molding an intermediate coil body in which a wire is wound in a substantially spiral shape in the axial direction. By adjusting the degree of deformation of the wire generated by press molding, the spring back of the wire generated when the wire is wound in a substantially spiral shape is reduced.

  The invention according to claim 2 is a method for producing a modified cross-section coil in which a coil having a modified cross section is manufactured by press-molding an intermediate coil body in which a wire is wound in a substantially spiral shape in the axial direction. By adjusting the ductility of the wire constituting the intermediate coil body and performing press molding on the intermediate coil body, the spring back of the wire generated when the wire is wound in a substantially spiral shape is reduced.

  According to a third aspect of the present invention, there is provided a method for producing a modified cross-section coil in which a coil having a modified cross section is manufactured by press-molding an intermediate coil body in which a wire is wound in a substantially spiral shape in the axial direction. The wire rod was wound in a substantially spiral shape by adjusting the degree of deformation of the wire rod caused by the press molding and the ductility of the wire rod constituting the intermediate coil body. The spring back of the wire material that occurs at the time is reduced.

  According to the invention described in claim 1, by adjusting the degree of deformation of the wire generated by press molding, a special process is performed to reduce the springback of the wire generated when the wire is wound in a substantially spiral shape. Without providing, it is possible to prevent the coil from being deformed by the springback.

  According to the second aspect of the present invention, the spring back of the wire that is generated when the wire is wound in a substantially spiral shape is reduced by adjusting the ductility of the wire constituting the intermediate coil body and performing press molding. In addition, it is possible to prevent the coil from being deformed by the spring back without providing a special process.

  According to the invention described in claim 3, when both the degree of deformation of the wire generated by press molding and the ductility of the wire constituting the intermediate coil body are adjusted, the wire is wound in a substantially spiral shape. In order to reduce the spring back of the generated wire, the deformation of the coil due to the spring back can be more accurately prevented without providing a special process.

<First Embodiment>
<Manufacturing process of coil>
In the manufacturing method of the modified cross-section coil according to the first embodiment of the present invention, the spring back of the wire 3 generated when the wire 3 is wound in a substantially spiral shape by adjusting the degree of deformation of the wire 3 generated by press molding. Is to be reduced. Further, in the present embodiment, a coil connecting body 21 having a substantially barrel shape (here, a substantially rectangular barrel shape having a rectangular cross-sectional shape) as shown in FIG. The coil connecting body 21 is divided into two at the central portion in the axial direction, so that the coil 1 having two irregular cross sections having a substantially truncated cone-shaped appearance shown in FIG. 12 is produced. That is, the coil connecting body 21 is configured by continuously connecting two intermediate coil bodies 23A and 23B in the axial direction, and each of the divided intermediate coil bodies 23A and 23B becomes the coil 1 having an irregular cross section.

  The coil connecting body 21 shown in FIG. 1 has a shape in which the upper and lower portions are substantially symmetrical with respect to the upside down with respect to the center portion, and lead portions 25 and 27 for connecting the wires to the upper and lower ends. A protruding portion 29 is formed in the central portion so as to protrude outward in a substantially U shape in plan view. By cutting the projecting portion 29, the upper and lower portions can be easily divided, and the remaining projecting portion 29 can form a lead portion for electrical connection.

  The flow of the manufacturing process of the coil 1 according to this embodiment will be described. First, the coil connecting body 21 is manufactured. As shown in FIG. 2, the production is performed by winding a wire 3 having a constant cross-sectional shape (for example, a substantially rectangular cross-sectional shape) around a predetermined core material 31 in a substantially spiral shape. Since the core material 31 has a certain substantially rectangular cross section, the coil connecting body 21 having a substantially columnar shape is produced. Leading portions 25 and 27 are formed at the upper and lower ends of the coil connecting body 21, and an overhanging portion 29 is formed at the central portion.

  Subsequently, as shown in FIG. 3, the produced coil connecting body 21 is set in the forming die 33 while being wound around the core material 31, and press forming is performed. The molding die 33 includes a pair of an upper die 35 and a lower die 37 that are disposed opposite to each other so as to form a substantially barrel-shaped (here, generally rectangular barrel-shaped) cavity 34 around the set core material 31. The upper die 35 is driven to the lower die 37 side by a press mechanism (not shown) to perform press molding. In the present embodiment, the molding die 33 is configured by the upper die 35 and the lower die 37 that are opposed to each other in the vertical direction. However, the molding die 33 is constituted by using another pair of dies that are opposed to each other in the horizontal direction or the like. May be.

  When the upper die 35 is lowered from the state shown in FIG. 3 and press molding is performed, in the molding die 33, the upper die 35 is lowered and schematically shown in FIGS. 4 (a) to 4 (c). Thus, the molding proceeds and finally the state shown in FIGS. 4C and 5 is obtained. That is, when press molding is started, as shown in FIG. 4 (a), the central portion of the coil connecting body 21 spreads outward in a substantially barrel shape, as shown in FIGS. 4 (b) and 4 (c). Further, press molding is performed such that the outer periphery of the coil connecting body 21 is along the inner peripheral surface of the cavity 34 of the mold 33.

  Here, regarding the core material 31, the core material 31 when the wire 3 is wound around the core material 31 to produce the coil connecting body 21 and the core material 31 installed in the mold 33 together with the coil connecting body 21 are: It may be different.

  In the state shown in FIG. 5 where the press molding is completed, the coil connecting body 21 has a substantially barrel shape corresponding to the shape of the cavity 34 formed by the outer periphery of the core material 31 and the inner periphery of the molding die 33. Molded. 3 and FIG. 5 is an escape portion provided in the lower mold 37 corresponding to the overhang portion 29.

  When the formation of the coil connecting body 21 is completed, the coil connecting body 21 is divided into two at the central portion as described above, thereby producing two coils 1 (see FIG. 12) having irregular cross sections.

<Setting of processing rate>
The wire 3 constituting the coil connecting body 21 is deformed from the state shown in FIG. 6 to the state shown in FIG. 7 along with the press forming. The degree of deformation of the wire 3 due to the press forming and the wire after the press forming. It was found by a test or the like that there is a correlation with the remaining amount of springback remaining in No. 3. In the present specification, the degree of deformation of the wire 3 is a concept including the processing rate of the wire 3.

  Specifically, a test was conducted on the relationship between the processing rate Pr with respect to the thickness of the wire 3 by press forming and the return angle θ (see FIG. 8) by the springback of the wire 3 after press forming. Here, the return angle θ is set as shown in FIG. That is, when the wire 3 is wound around the core 31 by a predetermined number of turns, the upper and lower lead portions 25 and 27 are pulled out in the same direction and press-molded, and then the core 31 is extracted from the coil connecting body 21. The upper and lower lead portions 25 and 27 are opened outward by the spring back remaining in the wire 3, and the angle formed by the lead portions 25 and 27 when opened is defined as a return angle θ.

When the thickness Pr of the wire 3 before and after press molding is defined as t1, t2 (see FIGS. 6 and 7),
Pr = (t1-t2) / t1 [%]
It is given by the relational expression. The coil connecting body 21 after press forming has a different thickness of the wire 3 depending on the portion. That is, as shown in FIG. 7, the thickness of the wire 3 after press forming gradually decreases from the minimum value (t2max) at the upper and lower end portions to the maximum value (t2min) at the center portion. The rate Pr has a maximum value at the center of the coil connecting body 21. Therefore, in the present embodiment, the relationship between the processing rate Pr and the remaining springback is examined on the basis of the maximum value (here, the processing rate at the center) of the processing rate Pr of each part of the coil connecting body 21. It was.

  FIG. 9 is a graph showing test results regarding the relationship between the processing rate Pr when the ductility described later of the wire 3 is kept constant (40%) and the return angle θ due to the springback remaining after press forming. As a result of the test, as shown in FIG. 9, when the maximum processing rate Pr is 52.0% (t1 = 2.04 mm, t2min = 0.98 mm), the return angle θ is 21.5 °, A result of 0.0 ° was obtained. In addition, when the maximum processing rate Pr was 55.7% (t1 = 2.21 mm, t2min = 0.98 mm), the return angle θ was 13.2 °. From this, it was found that the return angle θ decreases as the maximum processing rate Pr increases. In any test, the number of turns of the wire 3 is set to 36 turns.

  Therefore, in this embodiment, the remaining amount of the spring back is suppressed to a predetermined level or less by setting the maximum processing rate Pr at the time of press forming to be a predetermined reference value or more. As the specific reference value, for example, the maximum processing rate Pr is set to 55% or more.

  As described above, according to the present embodiment, the spring back of the wire 3 that is generated when the wire 3 is wound in a substantially spiral shape by adjusting the degree of deformation of the wire 3 that occurs during press molding of the coil connecting body 21. Therefore, the deformation of the coil 1 due to the spring back can be prevented without providing a special process.

  Further, in order to set the maximum working rate Pr of the thickness by press molding of each part of the wire 3 constituting the coil connecting body 21 to be a predetermined reference value (for example, 55%) or more, the spring back of the wire 3 is It can be accurately suppressed with press molding.

  In the present embodiment, the case where the coil connecting body 21 in which the two intermediate coil bodies 23A and 23B are connected is configured and the coil 1 having two irregular cross sections is manufactured by press forming is described. The method of suppressing the spring back by adjusting the degree of deformation of the wire 3 during press forming according to the embodiment is applied to the case where the coil 1 is manufactured by press forming the single intermediate coil body 11 shown in FIG. May be. In this case, the condition setting of the processing rate is performed on the basis of the processing rate of the upper end portion where the processing degree of the intermediate coil body 11 shown in FIG. 13 is maximum.

Second Embodiment
In the method for manufacturing a modified cross-section coil according to the second embodiment of the present invention, the wire 3 is wound in a substantially spiral shape by adjusting the ductility of the wire 3 constituting the coil connecting body 21 and performing press molding. The generated spring back of the wire 3 is reduced. Here, the manufacturing method according to the present embodiment is applied to the case where the coil connecting body 21 described above is configured and press-molded to manufacture the coil 1 having two irregular cross sections. You may apply when manufacturing the coil 1 by press-molding the single intermediate coil body 11 shown in FIG.

  As a result of tests and the like, it was found that there was a correlation between the ductility of the wire 3 constituting the coil connection body 21 and the remaining amount of springback remaining in the wire 3 after press forming.

  Specifically, a test was conducted on the relationship between the ductility of the wire 3 constituting the coil connection body 21 and the return angle θ (see FIG. 8) due to the spring back of the wire 3 after press molding. Here, the ductility of the wire 3 is obtained by a test prescribed in JISC3002, and generally, the sample is not subjected to a tensile test until a shear occurs when a tensile test is performed on the sample. The percentage of growth is expressed as a percentage. The ductility of the wire 3 varies depending on the part due to the influence of work hardening when the wire 3 is wound in a substantially spiral shape, but the value of the ductility of each part is averaged with respect to the longitudinal direction of the wire 3. Will be adopted.

  FIG. 10 is a graph showing the test results regarding the relationship between the ductility of the wire 3 and the return angle θ due to the springback remaining after the press forming when the processing rate with respect to the thickness of the wire 3 by press forming is kept constant. As a result of the test, as shown in FIG. 10, when the ductility is 40%, a return angle θ of 21.5 ° and a result of 16.0 ° are obtained, and when the ductility is 38%, A result that the return angle θ was 15.0 ° was obtained, and when the ductility was 35%, a result that the return angle θ was 11.8 ° and a result that was 12.7 ° were obtained. From this, it was found that the return angle θ decreases as the ductility decreases. In addition, in each test of FIG. 10, the processing rate Pr with respect to the thickness of the wire 3 by press molding is set to a constant value (the maximum processing rate is 52.0% (t1 = 2.04 mm, t2min = 0.98 mm)). The number of turns of the wire 3 is set to 36 turns.

  Therefore, in this embodiment, the remaining amount of the springback is suppressed to a predetermined level or less by setting the ductility of the wire 3 before press forming constituting the coil connecting body 21 to be a predetermined reference level or less. I am doing so. As the specific reference value, for example, the ductility is set to be 35% or less.

  As described above, according to this embodiment, the spring of the wire 3 generated when the wire 3 is wound in a substantially spiral shape by adjusting the ductility of the wire 3 constituting the coil connecting body 21 and performing press molding. In order to reduce the back, it is possible to prevent the coil from being deformed by the spring back without providing a special process.

  In addition, since the ductility of the wire constituting the coil connecting body 21 is set to be equal to or less than a predetermined reference level (for example, 35%), the spring back of the wire 3 can be accurately suppressed with press molding. it can.

<Modification>
As a modification of each of the above-described embodiments, press molding is performed on the coil connecting body 21 by adjusting both the degree of deformation of the wire 3 generated by press molding and the ductility of the wire 3 constituting the coil connecting body 21. Thereby, you may make it reduce the springback of the wire 3 which arises when winding the wire 3 in a substantially spiral shape. For example, a method for setting the maximum processing rate Pr during press forming to be equal to or higher than a predetermined reference value and setting the ductility of the wire rod 3 before press forming constituting the coil connecting body 21 to be equal to or lower than a predetermined reference level. Can be considered. In this way, by adjusting both the degree of deformation and the ductility of the wire 3, the remaining springback can be suppressed more accurately.

<Application example>
Next, an application example of the coil 1 having an irregular cross section manufactured by the manufacturing method according to each of the above embodiments will be described. In this application example, as shown in FIG. 11, the coil 1 is incorporated in the stator core of the motor, and the plurality of coils 1 are inserted into the plurality of cores 71 arranged at equal intervals in the circumferential direction. Arranged.

It is a perspective view of the coil connection body formed in the substantially barrel shape produced in the manufacture process by the manufacturing method of the odd-shaped section coil concerning a 1st embodiment of the present invention. It is explanatory drawing of the formation process of a coil connection body. It is explanatory drawing when a coil connection body is press-molded. FIG. 4A to FIG. 4C are explanatory views showing the progress in the mold during the press molding step by step. It is explanatory drawing which shows the state in the shaping | molding die at the time of completion | finish of press molding. It is explanatory drawing which shows the state of the wire before press molding. It is explanatory drawing which shows the state of the wire after press molding. It is explanatory drawing about the return angle by springback. It is a graph which shows the test result regarding the relationship between the processing rate Pr and return angle (theta) by the springback which remains after press molding. It is a graph which shows the test result regarding the relationship between ductility of a wire, and return angle (theta) by the springback which remains after press molding. It is a figure which shows the example of application of an irregular cross-section coil. It is a perspective view of the coil to which the manufacturing method of the irregular cross-section coil which concerns on this invention is applied. It is explanatory drawing of the manufacturing method of the irregular cross-section coil which concerns on a proposal example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coil 3 Wire material 21 Coil connection body 25, 27 Lead part 29 Overhang part 31 Core material 33 Mold 34 Cavity

Claims (3)

A method for producing a modified cross-section coil for producing a coil having a modified cross-section by press-molding an intermediate coil body in which a wire is wound in a substantially spiral shape in the axial direction,
A method of manufacturing a deformed cross-section coil, comprising: adjusting a degree of deformation of the wire generated by press molding to reduce spring back of the wire generated when the wire is wound in a substantially spiral shape. A method for producing a modified cross-section coil for producing a coil having a modified cross-section by press-molding an intermediate coil body in which a wire is wound in a substantially spiral shape in the axial direction,
By adjusting the ductility of the wire constituting the intermediate coil body and performing press molding on the intermediate coil body, the spring back of the wire generated when the wire is wound in a substantially spiral shape is reduced. A method for producing a modified cross-section coil. A method for producing a modified cross-section coil for producing a coil having a modified cross-section by press-molding an intermediate coil body in which a wire is wound in a substantially spiral shape in the axial direction,
When the wire rod is wound in a substantially spiral shape by adjusting the degree of deformation of the wire rod caused by press molding and the ductility of the wire rod constituting the intermediate coil body and performing press molding on the intermediate coil body A method for manufacturing a deformed cross-section coil, characterized by reducing spring back of the wire that occurs in a wire.

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