JP7488014B2 - Segment coil forming equipment - Google Patents

Description

The present invention relates to a segment coil molding device.

The drive motors installed in electric and hybrid vehicles are required to be small and have high output. For this reason, the coils of this type of motor are sometimes made of flat conductors with a rectangular cross section in order to increase the space factor and improve output efficiency. A well-known example of a coil using such a flat conductor is one in which multiple U-shaped segment coils are connected together.

As shown in Figs. 1(A) to (C), the segment coil has a pair of legs 101, 102 that extend approximately parallel to each other, and a connecting portion 103 that connects the ends of the legs. Bent portions 104, 105 are provided at the boundary between each leg 101, 102 and the connecting portion 103. The connecting portion 103 has a convex portion 103a provided in the center and inclined portions 103b provided on both sides of the convex portion 103a. One of the legs 101 may be provided with a shift portion 101a bent into a crank shape to adjust the radial position of the end (the lower end in the figure) when it is inserted into the slot of the stator core. The shift portion 101a is located near the bent portion 104 at the boundary between the one leg 101 and the connecting portion 103.

The following Patent Document 1 shows a method for forming a segment coil having a shift section. Specifically, after forming the shift section 101a in the straight rectangular conductor 100', as shown in Figures 11 and 12, the central portion of the rectangular conductor 100' is clamped between dies 201 and 202 to form the connecting section 103. After that, the portion of the rectangular conductor 100' that protrudes from the dies 201 and 202 is pressed by rollers 203 to form the bent sections 104 and 105 (see Figure 1).

At this time, as shown in FIG. 11, the part of the rectangular conductor 100' that is clamped and fixed by the dies 201 and 202 (fulcrum P) and the part that is pushed in by the roller 203 (force point Q) are offset in the horizontal direction via the shift part 101a. Therefore, when the rectangular conductor 100' is pushed downward by the roller 203, a moment load centered on the fulcrum P is applied to the rectangular conductor 100', which may cause the leg 101 to twist. If the leg 101 is twisted, it may not fit into the slot of the stator core, or poor welding may occur when welding the ends of the leg 101 together.

As a countermeasure to the above problem, for example, it is possible to anticipate the above-mentioned twisting and form a twist in the rectangular conductor 100' in the opposite direction to the above-mentioned twisting.

In addition, the following Patent Document 1 shows a method of forming a bent portion by pressing a portion of the rectangular conductor closer to the center than the shift portion with a roller. In this case, since no shift portion is provided between the portion of the rectangular conductor that is clamped and fixed by the mold (fulcrum) and the portion that is pressed by the roller (force point), these areas are not offset horizontally, and twisting of the legs can be avoided.

JP 2020-102943 A

However, when forming rectangular conductors with twisting in mind, it is inevitable that the precision of the areas where twisting is expected will deteriorate. In addition, it is not easy to set an appropriate expected amount of twist, which lengthens the design lead time. In addition, because the expected amount differs for each wire type of rectangular conductor, a forming die is required for each wire type, resulting in higher costs.

On the other hand, the method of Patent Document 1 does not cause the above-mentioned problems associated with the possibility of twisting. However, it is necessary to use rollers to press the narrow area of the rectangular conductor between the part that is clamped and fixed by the mold and the shift part, making it difficult to design the molding device, including the arrangement of the rollers.

The present invention aims to prevent twisting of the legs of a segment coil when forming a segment coil having a shift section, without anticipating twisting or pressing the part closer to the center than the shift section.

In order to solve the above problem, the present invention provides a segment coil molding device including a first leg having a shift portion bent into a crank shape, a second leg, and a connecting portion connecting the ends of the first leg and the second leg,
A fixing portion that fixes a region of the linear rectangular conductor having the shift portion formed thereon that is closer to the center than the shift portion;
a pressing portion that presses an area of the rectangular conductor closer to the end than the shift portion in a direction intersecting with a bending plane of the shift portion to form a bending portion closer to the center than the shift portion;
A segment coil molding device is provided that has a first guide portion that supports the side surface of the region of the flat rectangular conductor that is closer to the end portion than the shift portion.

In the above-mentioned forming device, when the region of the rectangular conductor closer to the end than the shift section (hereinafter also referred to as the "end section") is pressed by the pressing section to form the bent section, the first guide section can support the side of the end section of the rectangular conductor. This makes it possible to suppress twisting of the end section of the rectangular conductor, i.e., twisting of the first leg of the segment coil.

In particular, the first guide section supports the side of the end region of the rectangular conductor that is adjacent to the surface pressed by the pressing section and is farther from the region fixed by the fixing section, thereby effectively suppressing twisting of the end region.

Furthermore, by providing a second guide section that supports the side of the end region of the rectangular conductor adjacent to the surface pressed by the pressing section, which is closer to the region fixed by the fixing section, twisting of the end region can be more reliably suppressed.

For example, if the first guide part is provided on the fixed side, the first guide part must be installed in a location where it does not interfere with the pressing part, which limits the layout. Therefore, if the pressing part and the first guide part are made movable together, the first guide part will not interfere with the pressing part, making the layout easier.

Twists in the end region of the rectangular conductor are likely to occur when you start to press it with the pressing part. Therefore, it is preferable to start pressing the end region with the pressing part while supporting the side of the end region of the rectangular conductor with the first guide part.

As described above, the molding device of the present invention can prevent twisting of the legs of a segment coil having a shift section when molding the segment coil without anticipating twisting or pressing the part closer to the center than the shift section.

(A) is a front view of the segment coil, (B) is a side view of the same, and (C) is a plan view of the same. 1 is a plan view showing the state in which the central region of a rectangular conductor is pressed horizontally with a die. FIG. 1A and 1B are cross-sectional views showing the state in which the central region of a rectangular conductor is pressed with a die, in which (A) shows the state before pressing and (B) shows the state after pressing. 1 is a front view showing the state in which the central region of a rectangular conductor is pressed vertically with a die. FIG. 10 is a front view showing a state in which the first protruding region of the rectangular conductor is pressed by a roller. FIG. 6 is a side view of the rectangular conductor and the mold of FIG. 5 viewed from the direction A. 11 is a front view showing a state in which the second protruding region of the rectangular conductor is pressed by a roller. FIG. 8 is a side view of the rectangular conductor and the mold of FIG. 7 as viewed from the direction B. FIG. 2 is a cross-sectional view showing a schematic diagram of a rectangular conductor and a forming device. FIG. 2 is a cross-sectional view showing a flat rectangular conductor and a forming device according to another embodiment. FIG. 1 is a side view of a conventional forming device and a flat rectangular conductor formed by the device. FIG. 12 is a front view of the forming device and the rectangular conductor of FIG. 11 .

The following describes an embodiment of the present invention with reference to the drawings.

The segment coil 100 shown in Figures 1 (A) to (C) is used, for example, as a material for forming a stator coil of a drive motor for an electric vehicle such as a hybrid car or an electric car. The segment coil 100 is made of a linear rectangular conductor with an insulating coating covering the surface of a conductor wire with a rectangular cross section. The rectangular conductor has a pair of parallel wide surfaces (flatwise surfaces) that form the long sides of the rectangular cross section, and a pair of parallel narrow surfaces (edgewise surfaces) that form the short sides of the rectangular cross section.

The segment coil 100 is generally U-shaped and has a first leg 101, a second leg 102, and a connecting portion 103 that connects the ends of the legs 101, 102. At the boundaries between the legs 101, 102 and the connecting portion 103, there are bent portions 104, 105 that are bent edgewise (in the direction that curves the narrow surface).

The legs 101 and 102 are parallel to each other and are substantially linear. At the lower end (free end) of each leg 101 and 102, the insulating coating is removed to expose the conductor. The first leg 101 is provided with a shift portion 101a. The shift portion 101a is a portion curved in a crank shape in a bending plane intersecting with the bending planes of the bending portions 104 and 105. In the illustrated example, the shift portion 101a is curved in a crank shape in a bending plane perpendicular to the bending planes of the bending portions 104 and 105, and specifically, is curved in a crank shape in the flatwise direction (the direction in which the wide surface is curved). The shift portion 101a is provided near the upper end of the first leg 101, that is, near the bending portion 104 at the boundary between the first leg 101 and the connecting portion 103.

The connecting portion 103 has a convex portion 103a provided approximately in the center and inclined portions 103b provided on both sides of the convex portion 103a. The convex portion 103a is curved so as to be convex upward in the edgewise direction (see FIG. 1(A)) and is curved in a crank shape in the flatwise direction (see FIG. 1(C)). Note that the connecting portion 103 does not have to have the convex portion 103a.

The above-mentioned segment coil 100 is manufactured through (1) a shift section molding process, (2) a connecting section molding process, and (3) a leg section molding process.

(1) Shift portion molding process First, a straight rectangular conductor is clamped by a metal mold from both sides in the short side direction, and a predetermined portion of the rectangular conductor is bent into a crank shape in the flatwise direction to form the shift portion 101a.

(2) Joint Part Molding Process Next, as shown in FIG. 2, the first molding surfaces 11a, 12a of the pair of dies 11, 12 press the central region 103' (the region corresponding to the joint part 103) of the rectangular conductor 100' from both sides in the short side direction to bend it into a crank shape in the flatwise direction. At this time, the shift part 101a of the rectangular conductor 100' is arranged adjacent to the outside (end side) of the central region 103' pressed by the dies 11, 12. Then, as shown in FIG. 3(A) and (B), the second molding surfaces 11b, 12b of the pair of dies 11, 12 press the central region 103' of the rectangular conductor 100' from both sides in the long side direction to bend it so that it is convex upward in the edgewise direction (see FIG. 4). As a result, the joint part 103 including the convex part 103a and the pair of inclined parts 103b is molded in the rectangular conductor 100'.

(3) Leg Forming Process Next, the bent portions 104 and 105 are formed in the rectangular conductor 100'. The forming device used in this process has a fixing portion that fixes the central region 103' of the rectangular conductor 100', and a pressing portion that presses the protruding regions 101' and 102' of the rectangular conductor 100' that protrude from the fixing portion. In this embodiment, the fixing portion is the molds 11 and 12 that form the connecting portion 103, and the pressing portion is a roller.

2 and 4, after forming the connecting portion 103 in the rectangular conductor 100', the connecting portion 103 is clamped and fixed by the dies 11 and 12, and the protruding portion from the dies 11 and 12 is pressed by a roller. Specifically, as shown in FIG. 5, the first protruding region 101' (the region corresponding to the first leg portion 101) of the rectangular conductor 100' protruding from one side of the dies 11 and 12 is pressed downward by the roller 13, so that the boundary between the first protruding region 101' and the connecting portion 103 is bent in the edgewise direction to form the bent portion 104. The moving direction (pressing direction) of the roller 13 at this time is the direction intersecting with the bending plane of the shift portion 101a before being pressed by the roller 13. In this embodiment, the shift portion 101a before being pressed by the roller 13 is bent into a crank shape within a bending plane L (see FIG. 5) that is slightly inclined relative to the horizontal plane, and the roller 13 moves in a direction intersecting this bending plane L, which is the vertical direction in the illustrated example. Also, as shown in FIG. 7, by pressing downward with the roller 14 the second protruding region 102' (the region corresponding to the second leg portion 102) of the rectangular conductor 100' that protrudes from the molds 11 and 12 to the other side, the boundary between the second protruding region 102' and the connecting portion 103 is bent in the edgewise direction, forming the bent portion 105.

At this time, the second protruding region 102', which does not have a shift portion, is linearly continuous with the connecting portion 103 before being pressed by the roller 14 (see FIG. 7). Therefore, in FIG. 8, which is a side view seen from the direction A in FIG. 7, the end portion of the connecting portion 103 on the second protruding region 102' side (i.e., fulcrum P2) and the contact portion between the second protruding region 102' and the roller 14 (i.e., force point Q2) are arranged at the same horizontal position. Therefore, when pressed by the roller 14, no moment load is applied to the second protruding region 102', so the second protruding region 102' is pressed down without twisting, and the bent portion 105 and the second leg portion 102 are formed.

On the other hand, the first protruding region 101' having the shift portion 101a is connected to the connecting portion 103 through the shift portion 101a (see FIG. 5). Therefore, in FIG. 6, which is a side view seen from the A direction of FIG. 5, the end portion of the connecting portion 103 on the first protruding region 101' side (i.e., the fulcrum P1) and the contact portion between the first protruding region 101' and the roller 13 (i.e., the force point Q1) are arranged at positions offset in the horizontal direction. Therefore, by pressing the force point Q1 provided in the region (hereinafter referred to as the "end region X") of the first protruding region 101' of the rectangular conductor 100' downward with the roller 13, a moment load centered on the fulcrum P1 is applied to the end region X of the rectangular conductor 100'. As a result, as shown by the dotted line in FIG. 9, the end region X of the rectangular conductor 100' tries to twist and rotate. FIG. 9 is a schematic diagram showing the cross section of the rectangular conductor 100' at the fulcrum P1 and the cross section at the force point Q1 in the side view of FIG. 6, and the shift portion 101a provided between these cross sections is shown by a straight line (dotted line).

In the forming device according to the present invention, a guide section is provided to support the side surface (wide surface) adjacent to the upper surface (narrow surface) pressed by the roller 13 in the end region X of the rectangular conductor 100'. Specifically, as shown in FIG. 9, a first guide section 15 is provided to support the side surface 101b farther from the fulcrum P1, and a second guide section 16 is provided to support the side surface 101c closer to the fulcrum P1, out of a pair of side surfaces in the end region X. The guide sections 15 and 16 are provided with support surfaces 15a and 16a that support the side surfaces of the rectangular conductor 100'. The support surfaces 15a and 16a are parallel to the moving direction of the roller 13 (vertical direction in the illustrated example) and are composed of flat surfaces that are parallel to each other. The distance between the support surfaces 15a and 16a is approximately the same as or slightly larger than the short side dimension of the rectangular conductor 100'. The support surfaces 15a and 16a are provided at positions that support the extension direction region of the end region X of the rectangular conductor 100', including the force point Q1 (contact portion with the roller 13) (see FIG. 5). By supporting the side surface (wide surface) of the end region X with these guide portions 15 and 16, it is possible to restrict the rotation of the end region X around the fulcrum P1 and prevent twisting of the end region X.

In this embodiment, the roller 13 and the guide parts 15 and 16 can be raised and lowered together. As shown in FIG. 9, at least a part of the support surfaces 15a and 16a of the guide parts 15 and 16 is provided below the roller 13. When the roller 13 and the guide part 15 are lowered together from above the rectangular conductor 100', the end region X is inserted between the guide parts 15 and 16, and both side surfaces of the end region X are supported by the support surfaces 15a and 16a of the guide parts 15 and 16. In the illustrated example, tapered surfaces 15b and 16b that increase in distance as they go downward are provided below the support surfaces 15a and 16a of the guide parts 15 and 16, so that the end region X is guided by the tapered surfaces 15b and 16b and smoothly arranged between the support surfaces 15a and 16a.

Then, when the roller 13 and guide parts 15, 16 are further lowered, the roller 13 presses the upper surface of the end region X downward with both side surfaces of the end region X supported by the guide parts 15, 16. When the roller 13 starts to press the end region X, twisting is likely to occur in the end region X, so by starting to press the roller 13 into the end region X with the side surfaces of the end region X supported by the guide parts 15 as described above, twisting of the end region X can be effectively prevented.

Then, when the roller 13 and guide parts 15, 16 are further lowered to press down the first protruding region 101', the roller 13 presses the shift part 101a as shown by the two-dot chain line in FIG. 5. When the roller 13 and guide parts 15, 16 are further lowered, the roller 13 again presses the region (end part X) on the end side of the shift part 101a, and the bent part 104 and the first leg part 101 are formed as shown by the dashed line in the figure.

The present invention is not limited to the above embodiment. Other embodiments of the present invention will be described below, but explanations of the same points as the above embodiment will be omitted.

The embodiment shown in FIG. 10 differs from the above embodiment in that the second guide portion 16 that supports the side 101c of the pair of sides of the end region X of the rectangular conductor 100' that is closer to the fulcrum P1 is omitted. Even in this case, twisting of the end region X can be prevented by supporting one side 101b of the end region X with the guide portion 15 when the end region X is pressed downward with the roller 13.

In the above embodiment, the guide parts 15 and 16 are raised and lowered together with the roller 13, but this is not limiting, and for example, the guide parts may be provided on the fixed side.

In addition, the pressing part that presses the top surface of the rectangular conductor 100' is not limited to a rotatable roller, but may be a non-rotatable one (such as a mold).

In addition, when the top surface of the rectangular conductor 100' is pressed in with a roller, the fixing portion for fixing the connecting portion 103 is not limited to the dies 11 and 12 for forming the connecting portion 103, but may be other fixing means (such as a clamp device).

In addition, in the above embodiment, the bending portions 104 and 105 are bent in the edgewise direction, and the shift portion 101a is bent in the flatwise direction. However, this is not limited to the above. For example, the bending portions 104 and 105 may be bent in the flatwise direction, and the shift portion 101a may be bent in the edgewise direction.

11, 12 Mold (fixed part)
13 Roller (pressing part)
14 Roller 15 First guide portion 16 Second guide portion 100 Segment coil 101 First leg portion 101a Shift portion 102 Second leg portion 103 Connecting portion 104, 105 Bending portion 100' Flat rectangular conductor 101' First protruding region 102' Second protruding region 103' Central regions P1, P2 Support points Q1, Q2 Point of force X End region

Claims (5)

A molding device for a segment coil having a generally U-shaped configuration, the molding device comprising: a first leg having a shift portion bent into a crank shape; a second leg; and a connecting portion connecting the first leg and the second leg,
A fixing portion that fixes an area of the linear rectangular conductor having the shift portion formed on one end side of the center of the linear rectangular conductor, the area being closer to the center than the shift portion;
a pressing portion that presses a region of the rectangular conductor closer to the one end than the shift portion in a direction intersecting a bending plane of the shift portion to form a bending portion closer to the center than the shift portion;
A segment coil molding device having a first guide portion that supports the side of the flat rectangular conductor in a region closer to the one end than the shift portion. The segment coil molding device of claim 1, wherein the first guide portion supports the side of the flat rectangular conductor adjacent to the surface pressed by the pressing portion in the region closer to the one end than the shift portion, the side farther from the region fixed by the fixing portion. A segment coil molding device as described in claim 2, further comprising a second guide portion supporting the side of the flat rectangular conductor adjacent to the surface pressed by the pressing portion in the region closer to the one end side than the shift portion, the side closer to the region fixed by the fixing portion. The segment coil molding device according to any one of claims 1 to 3, in which the pressing part and the first guide part are movable together. The segment coil molding device according to any one of claims 1 to 4, in which the pressing part starts to press the rectangular conductor while the first guide part supports the side of the rectangular conductor.

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