JP5077674B2 - Method for forming coil end of stator coil - Google Patents

Description

  The present invention relates to a method for forming a coil end of a stator coil, and preferably relates to a method for forming a coil end of a stator coil having a coil end formed by bending an insulation-coated flat wire in a step shape.

  Constructing the conductor wire constituting the stator coil with a rectangular wire having a large cross-sectional area is suitable for improving the slot space factor of the rotating electrical machine. For example, Patent Document 1 discloses a rotating electric machine having a structure in which a stator coil having a coil end formed in advance using this type of flat wire is housed in an open slot type or split core type stator core. Moreover, shortening the axial protruding length of the coil end is beneficial in terms of downsizing the rotating electrical machine. Particularly in a rotating electrical machine having a large diameter and a small axial protrusion length, the effect of shortening the axial protrusion length of the coil end is great.

However, the use of this type of rectangular wire forming coil as a stator coil is beneficial in terms of improving the slot space factor as described above. However, since the rectangular wire is difficult to bend, the axial protrusion length of the coil end portion is difficult. There is a problem that the motor size increases due to an increase in the motor. In particular, in the distributed winding stator coil, the coil end portion is adjacent to other adjacent coil end portions with high density, and thus interference between the coil end portions of each conductor wire is particularly problematic.
Japanese Patent No. 3604326

  In order to solve this problem, the present applicant can minimize the axial projection length of the coil end by forming the coil end portions of the respective conductor wires of the stator coil in a stepwise manner and closely combining them. Possible stator coil structures are being considered.

  As a result, this stepped coil end portion is very excellent in terms of shortening the axial protrusion length of the coil end, but the step of forming a large number of corner portions on the insulation-coated rectangular wire is an insulating covering that covers each corner portion. It has been found that there is a problem that a large tensile stress is applied to the covering film, particularly to the insulating coating film covering the corner portions adjacent to both end portions of the coil end portion. For this reason, it is necessary to realize a good manufacturing method for bending the insulation covering rectangular wire stepwise while preventing the insulation covering from being damaged in order to shorten the axial protrusion length of the stator coil and to reduce the size of the rotating electrical machine. I found out.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for forming a stepped coil end portion that can satisfactorily prevent damage to an insulating coating by a simple process.

  According to the present invention, a coil end portion of a stator coil is manufactured by bending a predetermined coil end portion of an insulation-coated conductor wire obtained by insulating a rectangular wire, and both ends of the coil end portion are accommodated in slots of the distributed winding stator coil. It is applied to the coil end molding of a stator coil that is connected to each part.

  In the present invention, in particular, a pressing die set and a receiving die set arranged with a predetermined coil end portion of the insulating coated conductor wire are prepared. The pressing die set includes a plurality of pressing dies that are arranged side by side along the longitudinal direction of the coil end planned portion and that can advance and retract independently from each other in the direction perpendicular to the longitudinal direction of the coil end planned portion. The receiving mold set includes a plurality of receiving molds that are arranged side by side along the longitudinal direction of the coil end planned portion and that can advance and retract independently from each other in the direction perpendicular to the longitudinal direction of the coil end planned portion. Each of the plurality of pressing dies is arranged substantially facing each other, preferably one-to-one with each of the plurality of receiving dies. Using the push die set and the receiving die set having the above-described structure, a stepped coil end portion is formed by pushing and bending at a predetermined coil end portion of the insulated coated conductor wire.

  More specifically, the die pair is pushed in a direction perpendicular to the longitudinal direction in a state where a predetermined portion of the coil end planned portion is sandwiched by a die pair consisting of the push die and the receiving die facing each other. By sequentially executing a pushing and bending step of moving a predetermined portion of the coil end planned portion from the original position in a direction perpendicular to the longitudinal direction for each pair constituted by the push die and the receiving die. The step of the coil end is bent in a stepped manner from the center portion in the longitudinal direction toward the end portions on both sides thereof. In addition, the longitudinal direction in this specification shall mean the longitudinal direction of the coil end planned part of the insulation coating conductor wire before a coil bending.

  That is, according to the present invention, a single pressing die having a stepped pressing surface is pressed against a single receiving die having a stepped concave surface that is combined with the stepped pressing surface, thereby forming a stepped shape at a coil end planned portion at a stroke. Instead of forming the coil end portion, instead of using a pressing die set in which a plurality of pressing dies are arranged in the longitudinal direction and a receiving die set in which a plurality of receiving dies are arranged in the longitudinal direction, Each receiving mold is made to face one-to-one so as to sandwich a coil end planned portion. Each push die and each receiving die can be moved back and forth in the direction perpendicular to the longitudinal direction independently of each other. In this way, the operation of pushing in the direction perpendicular to the longitudinal direction across the predetermined portion of the coil end planned portion for each die pair composed of the push die and the receiving die facing each other can be executed in time sequence. Therefore, when one mold pair pushes and bends a predetermined portion of the coil end planned portion in a direction perpendicular to the longitudinal direction, the coil end planned portion can be freely drawn into this push bent portion, and as a result, insulation It is possible to prevent a strong tensile stress from being applied to the coated conductor wire. Thereby, the fall of the dielectric strength of the formed stepped coil end part can be prevented, and the bending work of the stepped coil end part is also facilitated.

  In a preferred embodiment, the step of bending the coil end planned portion by the pair of molds is sequentially performed from the central portion in the longitudinal direction of the coil end planned portion sequentially to both sides thereof.

  That is, according to this aspect, the above-described pushing and bending is performed in order from the longitudinal center portion of the stepped coil end portion toward both end portions thereof by each mold pair. As a result, when any of the mold pairs is displaced in the direction perpendicular to the longitudinal direction, particularly the other mold pairs in which the insulated conductor wire is drawn toward the mold pair do not interfere with it. Further, it is possible to prevent a strong tensile stress from being applied to the insulating coated conductor wire. As a result, a decrease in the dielectric strength of the formed stepped coil end portion can be prevented, and the bending work of the stepped coil end portion is facilitated.

  In a preferred embodiment, the longitudinal ends of the receiving mold are more than the longitudinal ends of one of the pressing molds that form a pair with the receiving mold at least the thickness of the insulating coated conductor wire, It is shifted in the longitudinal direction. As a result, when each mold pair moves in a direction perpendicular to the longitudinal direction, the coil end planned portion is formed between the pressing mold of the moving mold pair and the receiving mold of the mold pair adjacent to the pressing mold. The wire can be reliably accommodated, and as a result, unnecessary pulling force is not applied to the insulated conductor wire.

  Note that the insulation-coated conductor wire may be appropriately bent before the stepped coil end portion is formed by the pressing die set and the receiving die set. For example, the slot accommodating portion described above may be bent at a right angle with respect to the portion where the stepped coil end portion is to be formed. This corresponds to the formation of corner portions at both ends of the stepped coil end portion. In this way, waste of work space is reduced and work becomes easier.

  Alternatively, the slot holder may be bent at right angles to the stepped coil end, that is, the corners at both ends of the stepped coil end may be formed after the stepped coil end is formed.

  A preferred embodiment of a method for forming a stepped coil end portion of a stator coil according to the present invention will be described below. It should be noted that the present invention should not be construed as being limited to the following embodiments, and the technical idea of the present invention may be realized by a combination of other known techniques.

(Description of stator)
First, a stator coil of this embodiment that employs a stepped coil end will be described with reference to FIGS. FIG. 1 is a partial perspective view showing a part of one insulating coating flat wire 30, and FIG. 2 is a partial perspective view showing a coil end that is an assembly of stepped coil end portions 42.

  11 is a stator, 12 is a stator core, 13 is an end face of the stator core 12, and 20 is a stator coil. The stator 11 is used for a generator motor for driving a vehicle. A rotor (not shown) is rotatably accommodated inside the stator 11 in the radial direction. A large number of magnetic poles having different polarities alternately in the circumferential direction are formed by permanent magnets on the outer periphery of the rotor. The outer peripheral surface of the rotor faces the inner peripheral surface of the stator 11 via a minute air gap. The stator core 12 is formed by laminating electromagnetic steel plates having a predetermined thickness in the axial direction. The stator coil 20 is a three-phase winding. A single-phase wave winding is wound around the slot 14, and a single-phase wave winding is wound around the slot 15. In other words, a stator coil 20 having the same phase is wound around two slots 14 and 15 adjacent to each other to form a so-called two-slot structure for each pole and each phase.

  One phase coil (wave winding) of the stator coil 20 is formed by bending the insulation-coated rectangular wire 30 and then accommodating it in the slot 14 or 15 of the open slot structure of the stator core 12. Of course, a split stator core structure may be employed instead of the open slot structure.

  The insulating covering rectangular wire 30 is formed by coating an enamel layer such as polyamide imide on a copper wire having a substantially rectangular cross section, and further covering an outer side with an extrusion covering resin layer such as PPS. The total thickness of the insulating film is set to 100 μm to 170 μm. However, the insulation coating structure of the insulation coating rectangular wire 30 may adopt another known method. In this embodiment, the plurality of insulation coated rectangular wires 30 are arranged in a line in the slot depth direction in the slot, but the present invention is not limited to this, and may be arranged in a matrix in the slot. In addition, it is usual to provide insulating paper on the inner surface of the slot. However, in this embodiment, the insulating paper is omitted because a two-layer insulating layer is formed.

  The stator coil 20 will be further described with reference to FIGS. The insulation-coated rectangular wire 30 forming the stator coil 20 is separated from the slot accommodating portions 40 accommodated in the slots 14 and 15 of the stator core 12 respectively by two magnetic pole pitches extending in the axial direction and the circumferential direction while being separated by approximately one magnetic pole pitch in the circumferential direction. A coil end portion 42 that connects the end portions of the two slot accommodating portions 40 at both axial ends of the stator core 12 is provided.

(Description of shape of coil end portion 42)
The coil end portion 42 of the insulation covered rectangular wire 30 will be described in more detail with reference to FIG. 3 which is a schematic development view in the circumferential direction.

  At the center in the circumferential direction of the coil end portion (also referred to as a stepped coil end portion) 42 is provided a crown portion 1 that is a circumferential line portion that is located on the outermost side in the axial direction and extends in the circumferential direction. The part 42 is bent stepwise from the top part (circumferential line part) 1 toward the slot accommodating parts 40 on both sides.

  A step (also referred to as a step in the thickness direction) 3A is provided in the central portion of the top portion (circumferential line portion) 1 in the radial direction (thickness direction) by substantially the thickness of the insulating covering rectangular wire 30. This thickness direction step 3A is a step for allowing the coil end portion 42 and the other half portion to overlap each other in the radial direction by allowing the conductor end portion to overlap the other coil end portion. It is.

  2 to 4 are circumferential line portions extending in the circumferential direction, and 6 to 8 are axial line portions extending in the axial direction. C1 to C6 are corner portions forming a boundary portion between one adjacent circumferential line portion and one axial line portion. C <b> 7 is a corner portion that forms a boundary portion between the circumferential line portion 4 and the slot accommodating portion 40. The coil end portion 42 is formed in a step shape from the outermost crown 1 in the axial direction toward the left and right slot accommodating portions 40. In FIG. 3, the corners C1 to C7 are shown at right angles, but actually, the corners C1 to C7 are bent or curved with a predetermined radius of curvature within a range in which high-density mounting with other adjacent coil end portions 42 is possible. It only has to be.

(Mold structure)
First, the mold structure will be described with reference to FIG. This mold structure is referred to as a step-shaped coil end portion forming slide mold.

  100 is a receiving mold set, 200 is a pressing mold set, 101 to 104 are lower molds forming a receiving mold referred to in the present invention, and 201 to 204 are upper molds forming a pressing mold referred to in the present invention. The lower molds 101 to 104 and the upper molds 201 to 204 are configured to be individually movable up and down. The non-molded and linear insulating covering rectangular wire 10 is gently disposed between the lower molds 101 to 104 and the upper molds 201 to 204.

  The lower mold 102 is disposed adjacent to the outer side of the lower mold 101 in the center, the lower mold 103 is disposed adjacent to the outer side of the lower mold 102, and the lower mold 104 is disposed adjacent to the outer side of the lower mold 103. Similarly, the upper mold 202 is disposed adjacent to both sides of the central upper mold 201, the upper mold 203 is disposed adjacent to the outside of the upper mold 202, and the upper mold 204 is disposed adjacent to the outside of the upper mold 203. The central upper mold 201 is disposed above the central lower mold 101, and the left and right ends of the central lower mold 101 protrude from the left and right ends of the upper mold 201 to the left and right substantially by the thickness of the insulation covered rectangular wire 10. . Similarly, the other lower molds 102 to 104 protrude from the other upper mold 202 to the left and right by the thickness of the insulating coated rectangular wire 10.

(Bending of coil end portion 42)
Next, an example of bending the coil end portion 42 using the mold will be described with reference to FIGS.

(First bending process)
First, as shown in FIG. 4, unmolded between upper molds 201 to 204 that respectively configure the pressing molds of the pressing mold set and lower molds 101 to 104 that respectively configure the receiving molds of the receiving mold set. A linear insulating covering flat wire 10 is arranged (FIG. 4). At this time, the insulation-coated conductor wire 10 is freely movable in the longitudinal direction. Next, as shown in FIG. 5, the insulating covering rectangular wire 10 is sandwiched between the pair of the lower mold 101 and the upper mold 201, and the mold pair is lowered downward by a predetermined distance. Thereby, the parietal portion 1, the axial line portion 6, and the corner portions C1 and C2 are formed.

(Second bending process)
Next, as shown in FIG. 6, two pairs of molds with the lower mold 102 and the upper mold 202 are sandwiched between the insulating coated rectangular wires 10, and these mold pairs are lowered downward by a predetermined distance. Thereby, the circumferential direction line part 2, the axial direction line part 7, and the corner | angular parts C3 and C4 are formed.

(Third bending process)
Next, as shown in FIG. 7, two pairs of molds with the lower mold 103 and the upper mold 203 are sandwiched between the insulating coated flat wires 10, and these mold pairs are lowered downward by a predetermined distance. Thereby, the circumferential direction line part 3, the axial direction line part 8, and the corner | angular parts C5 and C6 are formed.

(4th bending process)
Next, the corner portion C7 and the circumferential line portion 3 between the coil end portion 42 which is the stepped coil end portion and the slot accommodating portion 40 are formed by the same method as described above or by another method. The

  In this way, a stepped coil end portion having a required number of steps is obtained by sequentially lowering a predetermined distance of these mold pairs by sandwiching a predetermined region of the insulation-coated rectangular wire 10 between the lower and upper mold pairs. The coil end part 42 can be formed.

(Subsequent steps)
Although one coil end portion 42 is formed by the above method, one phase coil of the stator coil has a plurality of coil end portions 42 and a plurality of slot accommodating portions 40 alternately. Accordingly, each stepped coil end portion of one phase coil is formed in sequence by moving the insulation-coated conductor wire by a predetermined pitch in the longitudinal direction of the insulation-coated conductor wire after forming one stepped coil end portion. be able to.

  In addition, a plurality of step-shaped coil end forming slide molds for forming different stepped coil end portions are arranged, and each stepped coil end portion of one phase coil is separated into separate stepped coil end portions. You may push-bend by the forming slide type | mold.

  The phase coil having the stepped coil end portion formed in this way is wound around the slot of the stator core together with the other phase coils (see FIG. 9).

(Modification)
In the above embodiment, the outermost corner C7 of the coil end portion 42 is formed after the other corners C1 to C6 are formed. Instead, the corner C7 may be formed in advance on the insulating coated conductor wire, and the insulating coated conductor wire may be formed in a folded shape.

  In this modification, the step of sequentially forming each stepped coil end portion of one phase coil will be described with reference to FIG.

  The insulating coated conductor wire 10 is formed with a corner C7 in advance, whereby the insulating coated conductor wire 10 is divided into a slot accommodating portion 40 and a coil end planned portion 42A. A slide mold 301 for forming a stepped coil end part for forming a stepped coil end part on the front side and a slide mold 302 for forming a stepped coil end part for forming a stepped coil end part on the rear side are provided. They are provided at predetermined positions. After the stepped coil end portion is formed by these stepped coil end portion forming slide molds 301 and 302, the insulation-coated conductor wire 10 is fed by one magnetic pole pitch in the X direction, and the stepped coil end portion forming slide die 301 is formed. , 302 form the next stepped coil end formation. Thereafter, this operation may be repeated sequentially.

  Note that the stepped coil end portion connecting the slot accommodating portions 40 arranged at the radially outer conductor accommodating position of the stator core slot is the slot accommodating portion 40 arranged at the radially inner conductor accommodating position of the stator core slot. The circumferential width is longer than the stepped coil end portion that connects them. Therefore, the step-shaped coil end portion forming slide mold for forming the step-shaped coil end portion connecting the slot accommodating portions 40 accommodated in the radially outer conductor accommodating positions in the slot is provided on the radially inner side in the slot. It is preferable to manufacture separately from the stepped coil end part forming slide mold for forming the stepped coil end part connecting the slot accommodating parts 40 accommodated in the conductor accommodating position.

(Example effect)
In the above-described embodiment, after the longitudinal center portion of the coil end planned portion is pushed and bent, the coil end planned portions on both sides thereof are sequentially pushed and bent. However, when the mold surface is displaced, it is not strongly rubbed or pulled strongly at the corner surface forming mold surfaces on both sides, thereby preventing the insulation film from being stretched or damaged. That is, the movement of the coil end planned portion of the insulation-coated conductor wire accompanying the pushing and bending of the coil end planned portion is performed before the other mold pair still strongly clamps the coil end planned portion, so that the above effect can be achieved. .

It is a fragmentary perspective view which shows a part of one insulation coating flat wire with a step-like coil end part. It is a fragmentary perspective view which shows the staircase-shaped coil end structure which is an aggregate | assembly of a staircase-shaped coil end part. It is a model circumferential direction expansion | deployment top view of a step-like coil end part. It is a model longitudinal cross-sectional view which shows the 1st shaping | molding process of a step-like coil end part. It is a model longitudinal cross-sectional view which shows the 2nd shaping | molding process of a staircase-shaped coil end part. It is a model longitudinal cross-sectional view which shows the 3rd shaping | molding process of a step-like coil end part. It is a model longitudinal cross-sectional view which shows the 4th shaping | molding process of a step-like coil end part. It is a schematic diagram for demonstrating the process of forming a step-like coil end part in a phase coil sequentially. FIG. 3 is a circumferential development view of a stator around which a phase coil having a stepped coil end portion is wound.

Explanation of symbols

C1 to C7 Corner part 1 Parietal part 2 Type pair 2 Circumferential line part 3 Circumferential line part 4 Circumferential line part 6 Axial line part 7 Axial line part 8 Axial line part 10 Insulated coated conductor wire (insulated coated flat wire) line)
DESCRIPTION OF SYMBOLS 11 Stator 12 Stator core 14 Slot 15 Slot 20 Stator coil 30 Insulation covering rectangular wire 40 Slot accommodating part 42A Coil end planned part 42 Coil end part 100 Receiving type set 101-104 Lower type (receiving type)
200 Press mold set 201-204 Upper mold (Push mold)
301 Slide type for forming stepped coil end part 302 Slide type for forming stepped coil end part

Claims (3)

A coil end portion of an insulating coated conductor wire formed by insulating coating a rectangular wire is bent to produce a coil end portion of the stator coil, and both ends of the coil end portion are respectively connected to the slot accommodating portions of the distributed winding stator coil. In the coil end molding method of the stator coil,
Having a stamping die set and a receiving die set arranged across a coil end planned portion of the insulation-coated conductor wire,
The pressing die set is arranged side by side along the longitudinal direction of the coil end planned portion and prepares a plurality of pressing molds that can advance and retract in a direction perpendicular to the longitudinal direction of the coil end planned portion independently of each other,
The receiving mold set has a plurality of receiving molds arranged side by side along the longitudinal direction of the coil end planned portion and capable of moving forward and backward in a direction perpendicular to the longitudinal direction of the coil end planned portion independently of each other,
Each of the plurality of pressing dies is arranged to face each of the plurality of receiving dies,
The mold pair is pushed in a direction perpendicular to the longitudinal direction with a predetermined portion of the coil end planned portion sandwiched by a mold pair consisting of the pressing die and the receiving die facing each other, and the predetermined coil end predetermined portion is predetermined. By sequentially executing a pushing and bending step of moving a part from the original position in a direction perpendicular to the longitudinal direction by a predetermined distance for each pair constituted by the push die and the receiving die,
A method for forming a coil end of a stator coil, comprising forming a stepped coil end portion by bending the predetermined portion of the coil end in a stepped manner from a longitudinal central portion thereof toward end portions on both sides. In the coil end shaping | molding method of the stator coil of Claim 1,
The stator coil coil end molding method, wherein the step of bending the coil end planned portion by each of the mold pairs is sequentially performed from the longitudinal center portion of the coil end planned portion to both sides sequentially. In the coil end shaping | molding method of the stator coil of Claim 1,
The longitudinal ends of the receiving mold are shifted in the longitudinal direction of the planned coil end portion by more than the thickness of the insulation-coated conductor wire than the longitudinal ends of one of the pressing dies forming a pair with the receiving mold. A method for forming a coil end of a stator coil.