JP2023036240A - Forming method for stator coil - Google Patents

Abstract

To keep coil ends after bending, arranged low when bending segment coils accommodated in a slot of a stator core.SOLUTION: A forming method for a stator coil includes: an insertion step of inserting tip parts 3 of projections 2 of segment coils 1 protruding toward one side in an axial direction of a stator core 11 into a plurality of groove parts 15 provided on a cylindrical bending jig 12; and a bending step of bending the projections 2 by axially rotating the bending jig 12 in a state where the tip parts 3 are inserted into the groove parts 15. The bending step includes: a bent part formation step of forming bent parts 2a and 2b having mutually different bending directions each at each base end side and each front end side of a plurality of projections 2 by axially rotating the bending jig 12; and a pressing step of moving the bending jig 12 in the axial direction to press a projection 2 closest to the stator core 11 among the plurality of projections 2 toward the stator core 11 side.SELECTED DRAWING: Figure 4

Description

The present invention relates to a method of forming a stator coil.

2. Description of the Related Art In recent years, in view of environmental problems, there has been an increasing trend to adopt motors in driving devices and peripheral devices of vehicles such as electric vehicles and hybrid vehicles. The motor mounted on the vehicle is required to have a high output in order to improve the driving performance of the vehicle, and is also required to be small due to the space available for installation.

Here, for the stator coil of the motor, a plurality of segment coils accommodated in the slots of the stator core are bent so that the protruding portions protruding from the stator core of the coil are twisted in the circumferential direction. After that, the tip portions of the projecting portions of the in-phase segment coils are joined together by welding or the like.

Here, Patent Literature 1 discloses an example of a configuration for bending projecting portions of a plurality of segment coils. That is, in Patent Document 1, a holding device formed in a cylindrical shape and holding tip portions of a plurality of protrusions, and a driving portion for relatively moving the holding device with respect to a stator core are provided, and the holding device includes a plurality of A plurality of grooves are provided in the circumferential direction into which each of the tip end portions of the driving portion can be inserted, and the driving portion can rotate in the circumferential direction with respect to the stator core while moving the holding device in a direction to approach the stator core in the axial direction. An apparatus for manufacturing a stator coil is disclosed. Further, in a state in which the tip portion is inserted into the groove portion of the holding device, the holding device is axially moved toward the stator core by the driving section and rotated in the circumferential direction, thereby causing the plurality of projections to be twisted in an S-shape. It is disclosed that the bending deformation is caused by

Japanese Patent Application Laid-Open No. 2020-36469

In order to reduce the size of the motor described above, it is important to minimize the coil end, which is the dimension in the height direction of the projecting portion of the segment coil, in the stator coil forming process. Here, in the bending described in Patent Document 1, the projecting portion is formed at two points, namely, the opening side edge of the groove provided in the bending jig and the opening side edge of the slot provided in the stator core. It is done by pushing and bending. At this time, the straight portion between the bent portion on the distal end side and the bent portion on the base end side (the stator core side) of the projecting portion is not supported or regulated at all. Therefore, when trying to push and bend the projecting portion while holding the tip of the projecting portion as described above, the area in the vicinity of the bent portion of the straight portion escapes, and the projecting portion is forced to follow the edge of each opening. cannot be bent. For the above reasons, it has been difficult to reduce the radius of curvature of the bent portion by the conventional method.

In view of the above circumstances, in the present specification, when bending the segment coil housed in the slots of the stator core, the radius of curvature of the bent portion of the protruding portion is reduced to lower the coil end after bending. Suppression is a technical problem to be solved.

The above problems are solved by a stator coil forming method according to the present invention. That is, this forming method is a method for forming a stator coil by subjecting a plurality of segment coils accommodated in slots of a stator core to a bending process accompanied by twisting. an inserting step of inserting the distal ends of projecting portions of the segment coils projecting to one axial side of the stator core into the plurality of grooves provided; and rotating the bending jig while the distal ends are inserted into the grooves. In the stator coil forming method, the bending process includes a bending process for bending the protruding part by rotating the bending jig so that the bending parts with different bending directions are formed. on the proximal side and the distal side of a plurality of protrusions, and moving the bending jig in the axial direction to form the proximal side bent portion and the distal side bent portion and a pushing step of pushing the protruding portion closest to the stator core among the plurality of protruding portions toward the stator core side by bringing the protruding portions of the two into contact with each other.

As described above, in the method of forming a stator coil according to the present invention, bent portions having mutually different bending directions are formed on the proximal end side and the distal end side of a plurality of projecting portions, and the plurality of projecting portions on which these bent portions are formed are formed. The portions are brought into contact with each other by moving the bending jig in the axial direction, and the protruding portion closest to the stator core among the plurality of protruding portions is pushed toward the stator core. By doing so, the pushing force in the axial direction of the bending jig is transmitted between the plurality of projections adjacent in the axial direction, and the pushing force is transferred to the proximal end of the projection closest to the stator core. can be given. Therefore, it is possible to form a bent portion with a small radius of curvature on the base end side of the projecting portion, thereby making it possible to lower the coil end. In addition, this method can be performed as part of the bending process of a conventional bending jig, and does not require modification of equipment, which is preferable in terms of work efficiency and cost.

In the method of forming a stator coil according to the present invention, the axial end portion of the bending jig has a predetermined angle with respect to the straight portion between the proximal-side bent portion and the distal-side bent portion of the projecting portion. A surface-to-surface contact portion may be provided. Further, in this case, in the pressing step, by moving the bending jig in the axial direction, the surface contact portion is pressed against the straight portion of the projection closest to the bending jig among the plurality of projections, A plurality of protrusions may be brought into contact with each other.

In this way, the straight portion of the projection can be pushed in at a predetermined angle by pushing in the straight portion of the projection using the surface contact portion that can come into surface contact with the straight portion of the projection at a predetermined angle. Therefore, it is possible to form the projecting portion including the straight portion with high accuracy. In addition, since the posture after pressing is stabilized by pressing by surface contact, the shape after molding is stabilized.

As described above, according to the present invention, when a segment coil accommodated in a slot of a stator core is bent, the radius of curvature of the bent portion of the protruding portion is reduced to lower the coil end after bending. can be suppressed.

4 is a flow chart showing a procedure of a stator coil forming method according to an embodiment of the present invention; FIG. 2 is an enlarged side view of a main portion of a molding apparatus for carrying out the molding method shown in FIG. 1, and is an enlarged side view of a main portion showing a state before the start of an insertion step; FIG. 2 is an enlarged side view of a main portion of a forming apparatus for carrying out the forming method shown in FIG. 1, and is an enlarged side view of a main portion showing a state at the end of a bending portion forming step; FIG. 2 is an enlarged side view of a main portion of a forming apparatus for carrying out the forming method shown in FIG. 1, and is an enlarged side view of a main portion showing a state at the end of a bending portion forming step;

Hereinafter, the details of a stator coil molding method according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1A, the stator coil forming method according to the present embodiment includes an inserting step S1 and a bending step S2. The bending step S2 includes a bending portion forming step S21 and a pressing step S22, as shown in FIG. 1(b). Hereinafter, after explaining the structure of the molding apparatus 10 used for each process S1, S2 (S21, S22), the details of each process S1, S2 will be explained.

FIG. 2 shows an enlarged side view of a main portion of the stator coil forming apparatus 10 according to the present embodiment. As shown in this figure, a molding apparatus 10 according to this embodiment mainly includes a stator core 11 and a bending jig 12 . The stator core 11 has a cylindrical shape, and a plurality of slots 13 are formed in the axial end face of the stator core 11 at predetermined intervals in the circumferential direction of the stator core 11 . A plurality of slots 13 are formed along the radial direction of the stator core 11 . A segment coil 1 constituting a stator coil is accommodated in each slot 13 , and a protruding portion 2 protrudes to one side of the stator core 11 in the axial direction. Before bending by the bending jig 12, the projecting portion 2 of each segment coil 1 extends linearly along the axial direction of the stator core 11, as shown in FIG. None.

The opening-side edge of each slot 13 on the side where the projecting portion 2 protrudes, particularly the opening-side edge 14 in the circumferential direction functions as a bending surface for the projecting portion 2 in the bending step S2. Therefore, the curvature radius of the opening-side edge portion 14 is set to a predetermined size in consideration of the curvature radius of the base-side bent portion 2a (see FIG. 3) to be formed in the projecting portion 2. FIG.

The bending jig 12 has a cylindrical shape, and as shown in FIG. are formed at predetermined intervals in the circumferential direction. Here, a plurality of bending jigs 12 having different outer diameters are arranged concentrically at positions facing the stator core 11 in the axial direction, and the bending jigs 12 are independent of each other. It is configured to be axially rotatable while moving in the axial direction. Specifically, the axial movement and axial movement are performed so that the protruding portion 2 of the segment coil 1 having the tip portion 3 inserted into the groove portion 15 can be twisted up to a predetermined twisting angle (provided with an S-shaped bending deformation). At least one of the position and speed of rotation is controllable.

A circumferential opening side edge portion 16 of each groove portion 15 functions as a bending surface in the bending step S<b>2 for the projecting portion 2 . Therefore, the curvature radius of the opening-side edge portion 16 is set to a predetermined size in consideration of the curvature radius of the tip-side bent portion 2b (see FIG. 3) formed in the projecting portion 2. FIG.

Further, in the present embodiment, surface contact portions 17 are provided between the circumferential groove portions 15 of the bending jig 12 . Specifically, the surface contact portion 17 is formed by the straight portion 2c of the projecting portion 2 formed with the proximal side bent portion 2a and the distal side bent portion 2b in the bending portion forming step S21 described later (see FIG. 3 for both). ) and a predetermined angle. Therefore, in this embodiment, the surface contact portion 17 has an inclined surface shape forming the above-described predetermined angle. The operation (action) of this surface contact portion 17 will be described later.

Next, steps S1 and S2 (S21 and S22) of the stator coil forming method using the forming apparatus 10 configured as described above will be described in chronological order.

(S1) Insertion Step In this step S1, the distal end portion 3 of the projecting portion 2 of the segment coil 1 accommodated in the slot 13 of the stator core 11 is inserted into the corresponding groove portion 15 of the jig 12 for bending. That is, as shown in FIG. 1, the bending jig 12 located above the distal end portion 3 of the projecting portion 2 projecting from each slot 13 is axially moved toward the stator core 11 side. As a result, each tip 3 is inserted into the groove 15 of the bending jig 12 . At this time, the opening side edge portion 16 and the surface contact portion 17 can function as a guide surface for guiding the tip portion 3 to the groove portion 15 .

(S2) Bending step (S21) Bending portion forming step After inserting the distal end portion 3 into the groove portion 15 as described above, the bending jig 12 is axially rotated, or the bending jig 12 is bent. By axially rotating along with axial movement in a direction to approach the stator core 11 , the projecting portion 2 is subjected to a bending process accompanied by twisting. As a result, the proximal side of the projecting portion 2 is bent by the opening side edge portion 14 of the slot 13 and the distal end side of the projecting portion 2 is bent by the opening side edge portion 16 of the groove portion 15 . As a result, as shown in FIG. 3, bent portions 2a and 2b whose bending directions are different from each other are formed on the proximal end side and the distal end side of the projecting portion 2. As shown in FIG. It should be noted that the radius of curvature of the corresponding opening side edges 14, 16 of the bent portions 2a, 2b is larger than the curvature radius of the opening side edges 14, 16 at the stage where step S2 is finished.

(S22) Pushing Step In this step S22, the bending jig 12 is moved further in the axial direction from the state in which the bent portions 2a and 2b are formed in the projecting portion 2 (the state shown in FIG. 3), thereby bending the bent portion 2a. , 2b are brought into contact with each other, the protrusion 2 closest to the stator core 11 is pushed toward the stator core 11 side. More specifically, the bending jig 12 is moved further toward the stator core 11 from the state shown in FIG. ) are pushed downward to bring the axially adjacent protrusions 2 into contact with each other (see FIG. 4). As a result, the pressing force from the bending jig 12 applied to the uppermost projecting portion 2 is transmitted to the lowermost projecting portion 2 via the intermediate projecting portion 2 . As a result, the protruding portion 2 facing the bent surface (opening side edge portion 14) of the stator core 11 is pushed and bent with a sufficient pushing force, so that the curvature of the proximal side bent portion 2a becomes large (the curvature radius becomes small). The projection 2 is reshaped as follows. Further, in this case, since the protruding portion 2 is restrained by the adjacent protruding portions 2, all the protruding portions 2, not limited to the lowermost protruding portion 2 and not limited to the base end side bent portion 2a, are restrained. bent portion 2a. A sufficient bending force acts on 2b, and each protruding portion 2 is reshaped so that the curvature of each bent portion 2a, 2b increases (see FIG. 4).

As described above, in the stator coil molding method according to the present embodiment, the bent portions 2a and 2b having different bending directions are formed on the proximal end side and the distal end side of the plurality of projecting portions 2, and these bent portions 2a are formed. , 2b are brought into contact with each other by moving the bending jig 12 in the axial direction, and the protrusion 2 closest to the stator core 11 among the plurality of protrusions 2 is pushed toward the stator core 11. (see Figures 3 and 4). By doing so, the pushing force in the axial direction of the bending jig 12 is transmitted between the plurality of projecting portions 2 adjacent in the axial direction, and the base end side of the projecting portion 2 closest to the stator core 11 is transmitted. can be applied with the pushing force. Therefore, it is possible to form the bent portion 2a with a small radius of curvature on the base end side of the projecting portion 2, thereby making it possible to lower the coil end. In addition, this method can be performed as part of the bending process S2 of the bending jig 12, and does not require any equipment change, which is preferable in terms of work efficiency and cost.

Further, in this embodiment, the bending jig 12 is provided with an inclined surface-shaped surface contact portion 17 that is in surface contact with the straight portion 2c at a predetermined angle, and the bending jig 12 is moved in the axial direction so that the surface Since the straight portion 2c is pushed by the contact portion 17, the shape after the pushing, more precisely, the angle of the straight portion 2c is stabilized. Therefore, the bent portions 2a and 2b having a large curvature can be stably formed with higher precision.

Although one embodiment of the present invention has been described above, the stator coil molding method according to the present invention can employ configurations other than those described above without departing from the scope of the present invention.

For example, in the above-described embodiment, the projecting portion 2 is straightened by forming the proximal side bent portion 2a and the distal side bent portion 2b with the surface contact portion 17 provided between the grooves 15 of the jig 12 for bending. Although the case where the pushing force is applied to the base end side of the protrusion 2 located closest to the stator core 11 by pushing the portion 2c to bring the adjacent protrusions 2 into contact with each other is, of course, limited to this. can't For example, although not shown, a plurality of projecting portions projecting from between the grooves 15 toward the stator core 11 are provided, and the plurality of projecting portions are straightened by moving the bending jig 12 in the axial direction after the bending portion forming step S21. You may make it press against the part 2c. In short, the bending jig 12 is moved in the axial direction so that the projections 2 formed with the bent portions 2a and 2b can be pushed in, and the adjacent projections 2 can be brought into contact with each other. The configuration of the tool 12 or the forming apparatus 10 provided with this bending tool 12 is arbitrary. For example, as long as the straight portion 2c is not deformed unnecessarily, it does not matter whether the contact state between the pressing portion of the molding device 10 and the projecting portion 2 is surface contact or point contact.

1 segment coil 2 protruding portion 2a bent portion (base end side)
2b bending part (tip side)
2c Straight portion 3 Tip portion 10 Forming device 11 Stator core 12 Bending jig 13 Slot 14 Opening side edge (slot)
15 Groove 16 Opening side edge (groove)
17 Surface contact portion S1 Inserting step S2 Bending step S21 Bending portion forming step S22 Pushing step

Claims (2)

A method for forming a stator coil by subjecting a plurality of segment coils housed in slots of a stator core to bending with twisting, comprising:
an inserting step of inserting distal ends of protruding portions of the segment coil protruding toward one axial side of the stator core into a plurality of groove portions provided in a tubular bending jig;
A method for forming a stator coil, comprising a bending step of performing the bending process on the projecting portion by axially rotating the bending jig in a state in which the tip end portion is inserted into the groove portion,
The bending step includes a bending portion forming step of forming bent portions having different bending directions on the proximal end side and the distal end side of the plurality of projecting portions by axially rotating the bending jig;
By moving the bending jig in the axial direction and bringing the plurality of projecting portions formed with the base-side bent portion and the tip-side bent portion into contact with each other, the stator core is bent out of the plurality of projecting portions. and a pushing step of pushing the projecting portion closest to the stator core toward the stator core. An axial end portion of the bending jig has a surface contact portion capable of surface contact at a predetermined angle with a straight portion between the proximal side bending portion and the distal side bending portion of the projecting portion. provided,
In the pushing step, by moving the bending jig in the axial direction, the surface contact portion is pressed against the straight portion of the protrusion that is closest to the bending jig among the plurality of protrusions. 2. The method of forming a stator coil according to claim 1, wherein the plurality of protrusions are brought into contact with each other.

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