Ring for collecting and distributing electricity, electric motor and method for manufacturing an electric motor

Abstract

Ring for collecting and distributing electricity (4) for collecting and distributing multiphase currents with different phases from / to several windings (32U, 32V, 32W), comprising the following: several bus rings (41, 42, 43) which are provided for the respective phases and are arranged parallel to each other along an axial direction, and a ring-shaped holder (5) for holding the multiple bus rings, wherein the holder comprises several separate arc-shaped retaining elements (50), wherein several retaining grooves (50a, 50b, 50c) for holding the several bus rings on the several retaining elements are designed such that they open on the outside of the holder, wherein each of the multiple bus rings is formed by bending a single continuous wire-shaped conductor such that multiple held sections (410, 420, 430) to be held by the holder and multiple connecting sections (411, 421, 431) to be arranged in a ring shape between the multiple held sections and connected to the windings, wherein the connecting sections (411, 421, 431) protrude outwards from the holder in order to be connected to the windings by crimping in a circumferential direction, and wherein a diameter reduction of the multiple bus rings by crimping is limited by a contact between the multiple retaining sections in the circumferential direction, wherein each of the multiple retaining elements comprises an inner wall section (510) extending in the circumferential direction of the holder (5) and multiple projecting wall sections (511) extending outwards from the inner wall section (510), wherein the retaining grooves (50a, 50b, 50c) are formed between the multiple projecting wall sections (511), wherein both circumferential ends of the inner wall section (510) extend in a circumferential direction beyond the several projecting wall sections (511), and wherein the holder (5) is designed such that the inner wall sections (510) of the multiple retaining elements (50) come into contact with each other through crimping.

Description

Background of the invention 1. Field of the invention

[0001] The invention relates to a ring for collecting and distributing electricity for collecting and distributing multiphase currents with multiple phases from / to multiphase windings, an electric motor provided with the ring for collecting and distributing electricity, and a method for manufacturing the electric motor. 2. Description of the state of the art

[0002] An electric motor used as a power source for a vehicle, etc., has a stator with multiphase windings, each wound on several core elements, a rotor that rotates relative to the stator, and a ring for collecting and distributing electricity to collect and distribute electric currents from / to the multiphase winding(s) of the stator (see e.g. JP 2015 - 46 958 A).

[0003] The ring for collecting and distributing electricity, described in JP 2015-46958A and its related patent US 2015 / 0061433A1, is provided with several annular bus rings (ring-shaped conductors) corresponding to the respective phases of the multiphase windings, and several fastening elements for connecting the multiple bus rings to one another. Several recesses for receiving the multiple bus rings are formed on the fastening elements. Connecting sections, intended for connection to the ends of the windings, are provided on each of the multiple bus rings, projecting radially between a pair of circumferentially adjacent bus rings.

[0004] Each connecting section of each bus ring consists of an arc-shaped section and a pair of wave sections opposite each other circumferentially, with the arc section positioned between them. Outgoing wires are inserted as a section of the windings between the pairs of wave sections. The connecting sections and the outgoing wires are fused and joined together by thermal crimping (fusion) of the outgoing wires between the pairs of wave sections, thus electrically connecting the bus rings to the windings.

[0005] From EP 2 590 303 A2 it is known to make the connection between (phase) bus rings and windings in a radially outward direction.

[0006] WO 2015 / 041 243 A1 discloses that connecting sections of the bus ring can project radially inwards or radially outwards, depending on the requirements. Summary of the invention

[0007] When attaching the bus ring described in JP 2015-46958A to the stator, the bus ring is placed on the stator with the outgoing wires (windings) protruding, and the several connection sections are then thermally crimped sequentially. During thermal crimping, the gap between the pair of shaft sections of each connection section narrows. This can gradually reduce the diameter of the bus ring, causing misalignment between some connection sections and outgoing wires (windings). In this case, the position of the bus ring or the positions of the outgoing wires must be corrected, resulting in increased labor time.

[0008] It is an object of the invention to provide a ring for collecting and distributing electricity which prevents a diameter reduction of bus rings caused by thermal crimping of connection sections on windings, as well as an electric motor which uses the ring for collecting and distributing electricity, and a method for manufacturing the electric motor.

[0009] The present invention is defined in the independent claims. The dependent claims define embodiments of the invention.

[0010] According to one embodiment, a ring for collecting and distributing electricity is provided for collecting and distributing multiphase currents with different phases from / to several windings, comprising: several bus rings, provided for the respective phases and arranged parallel to each other along an axial direction, and a ring-shaped holder for holding the multiple bus rings the holder comprises several separate arc-shaped holding elements, wherein several retaining grooves for holding the several bus rings on the several retaining elements are designed such that they open on the outside of the holder, wherein each of the multiple bus rings is formed by bending a single continuous wire-shaped conductor such that multiple held sections, which are to be held by the holder, and multiple connecting sections, which are arranged between the multiple held sections and are connected to the windings, are arranged in a ring shape, wherein the connecting sections protrude outwards from the holder in order to be connected to the windings by crimping in a circumferential direction, and where the diameter reduction of the multiple bus rings through crimping is limited by a contact between the multiple holding sections in the circumferential direction.

[0011] According to another embodiment, an electric motor is provided which includes: the ring for collecting and distributing electricity according to the above embodiment (1), a stator capable of generating a rotating magnetic field through electric currents flowing through the multiple windings, and a rotor that is rotated relative to the stator by the rotating magnetic field.

[0012] According to a further embodiment, a method for manufacturing an electric motor is provided, comprising a rotor, a stator capable of generating a magnetic field to rotate the rotor by means of electric currents flowing through windings, and a ring for collecting and distributing electricity for collecting and distributing multiphase currents with different phases from / to the winding(s). wherein the ring for collecting and distributing electricity comprises several bus rings, which are provided for the respective phases and are arranged parallel to each other along an axial direction, and an annular holder for holding the several bus rings, the holder comprises several separate arc-shaped holding elements, wherein several retaining grooves for holding the several bus rings on the several retaining elements are designed such that they open on the outside of the holder, wherein each of the multiple bus rings is formed by bending a single continuous wire-shaped conductor such that multiple held sections, which are to be held by the holder, and multiple connecting sections, which are arranged between the multiple held sections and are connected to the windings, are arranged in a ring shape, wherein the connecting sections protrude outwards from the holder in order to be connected to the windings by crimping in a circumferential direction, the procedure includes: Arranging the multiple bus rings parallel to each other along an axial direction, Arranging the multiple retaining elements by sliding them from the inside towards the outside relative to the multiple bus rings, which are arranged in parallel, so that the held sections of the multiple bus rings are each received in the multiple retaining grooves; and Connecting the multiple bus rings to the windings by crimping the connection sections in a circumferential direction, wherein the diameter reduction of the multiple bus rings by crimping is limited at the time of connection by a contact between the multiple holding sections in the circumferential direction. Effects of the invention

[0013] According to one embodiment, a ring for collecting and distributing electricity, which prevents a reduction in the diameter of bus rings caused by thermal crimping of connection sections on windings, as well as an electric motor which uses the ring for collecting and distributing electricity, and a method for manufacturing the electric motor can be provided. Brief description of the drawings

[0014] Next, the present invention will be explained in more detail in conjunction with the accompanying drawings, wherein: Fig. 1 is a schematic representation showing a general configuration of an electric motor to illustrate functions of a ring for collecting and distributing electricity in an embodiment of the present invention; Fig. 2 is a perspective view showing an exemplary configuration of a core element; Fig. 3 is a perspective view showing the ring for collecting and distributing electricity; Fig. 4 is a perspective exploded view showing the ring for collecting and distributing electricity; Fig. 5A is a top view showing the ring for collecting and distributing electricity; Fig. 5B is a side view showing the ring for collecting and distributing electricity; Fig. Figures 6A to 6D show an exemplary configuration of a retaining element, where Fig. 6A is a perspective view, Fig. 6B is a top view, Fig. 6C is a cross-sectional view that is on a line AA of Fig. 6B is taken, and Fig. 6D is a partially enlarged view showing one end of the perimeter of the retaining element, which is in Fig. 6B is shown; Fig. Figure 7 is a representation showing a holding element arrangement step in the process for manufacturing the electric motor, and Fig. 8A and Fig. 8B explanatory diagrams are shown showing how a connecting section of a second bus ring is to be connected to an end section of a V-phase winding, wherein Fig. 8A shows a state before crimping and Fig. 8B shows a state after crimping. Detailed description of the preferred embodiments

[0015] A ring for collecting and distributing electricity, an electric motor, and a method for manufacturing the electric motor in an embodiment of the invention are described with reference to Fig. 1 to 8B described.

[0016] Fig. Figure 1 is a schematic representation showing a general configuration of an electric motor 1 to illustrate functions of a ring for collecting and distributing electricity.

[0017] The electric motor 1 serves as a drive source for, for example, a vehicle such as an electric car and is equipped with a rotor 2, a stator 3 and a ring for collecting and distributing electricity 4, which has a first to third bus ring 41 to 43 and a neutral bus bar 44.

[0018] The rotor 2 has a shaft 21, which is rotatably mounted by a shaft bearing (not shown) to be arranged concentrically with the stator 3, and a cylindrical magnet 22, which is magnetized alternately with S and N in one circumferential direction and is fixed to an outer circumferential surface of the shaft 21. The stator 3 has several ring-shaped core elements 31, which are made of a soft magnetic material, and windings 32, each wound onto the several core elements 31.

[0019] In the present embodiment, eighteen core elements 31 are arranged in a ring around an axis of rotation O of which Fig. The eighteen core elements 31 are arranged as shown in the shaft 21. They consist of six U-phase core elements 31U, six V-phase core elements 31V, and six W-phase core elements 31W and are arranged such that along a direction of rotation R of the rotor 2, which is in Fig. Figure 1 shows a V-phase core element 31V adjacent to a U-phase core element 31U, a W-phase core element 31W adjacent to the V-phase core element 31V, and another U-phase core element 31U adjacent to the W-phase core element 31W. Although several (eighteen) ring-shaped core elements 31 are used in the present embodiment, in a further embodiment a toroid can be used as the integrated multiple core elements 31.

[0020] U-phase windings 32U (a subgroup of windings 32) are wound onto the U-phase core elements 31U, and electricity is collected and distributed to / from the U-phase winding(s) 32U via the first bus ring 41. V-phase windings 32V (another subgroup of windings 32) are wound onto the V-phase core elements 31V, and electricity is collected and distributed to / from the V-phase winding(s) 32V via the second bus ring 42. W-phase windings 32W (another subgroup of windings 32) are wound onto the W-phase core elements 31W, and electricity is collected and distributed to / from the W-phase winding(s) 32W via the third bus ring 43. Thus, the ring for collecting and distributing electricity 4 is able to collect and distribute electric currents with different phases (U, V and W phase) from / to the multiple windings (32U, 32V and 32W).

[0021] Each U-phase winding 32U is arranged such that one end section 321U, which is one of two end sections, is electrically connected to the first bus ring 41, and another end section 322U is electrically connected to the neutral bus bar 44. Similarly, each V-phase winding 32V is arranged such that one end section 321V, which is one of two end sections, is electrically connected to the second bus ring 42, and another end section 322V is electrically connected to the neutral bus bar 44. Furthermore, each W-phase winding 32W is arranged such that one end section 321W, which is one of two end sections, is electrically connected to the third bus ring 43, and another end section 322W is electrically connected to the neutral bus bar 44.

[0022] Each of the first to third bus rings 41 to 43 has a power supply section (412, 422, 432), and drive currents with sinusoidal waveforms that are phase-shifted by 120 degrees are supplied by an inverter (not shown) via the power supply sections 412, 422, and 432. The drive currents generate a rotating magnetic field in the stator 3. The magnet 22 then receives a torque generated by an attractive and a repulsive force caused by the rotating magnetic field, thus rotating the shaft 21 about the axis of rotation O. In other words, the rotor 2 is rotated relative to the stator 3 by a magnetic force generated by supplying currents to the U-phase windings 32U, the V-phase windings 32V, and the W-phase windings 32W.

[0023] Fig. Figure 2 is a perspective view showing an exemplary configuration of a core element 31U with the U-phase winding 32U wound on it. The U-phase core element 31U is formed by laminating several electromagnetic steel sheets 310, which are held by an insulator 33 made of an insulating material. The U-phase winding 32U is wound around the several electromagnetic steel sheets 310, with the insulator 33 positioned between them. The end section 321U and the other end section 322U of the U-phase winding 32U extend out of the stator 3 in an axial direction and project from the insulator 33. The V-phase core element 31V and the W-phase core element 31W are not shown in the drawing, but are configured in the same way as the U-phase core element 31U.

[0024] Fig. Figure 3 is a perspective view showing the ring for collecting and distributing electricity. Figure 4 shows the ring for collecting and distributing electricity. Fig. Figure 4 is a perspective exploded view showing the ring for collecting and distributing electricity. Fig. 5A is a top view showing the ring for collecting and distributing electricity 4 and Fig. Figure 5B is a side view showing the ring for collecting and distributing electricity 4. In the following description, a direction parallel to the axis of rotation O of shaft 21 (in Fig. 1 shown) is called an axial direction and a direction that intersects with the axis of rotation O and is also orthogonal to the axial direction is called a radial direction.

[0025] The ring for collecting and distributing electricity 4 comprises the first to third bus rings 41 to 43, the neutral bus bar 44, and an annular holder 5 for holding the first to third bus rings 41 to 43 and the neutral bus bar 44. The holder 5 consists of several separate arc-shaped retaining elements 50 arranged along a circumferential direction.

[0026] The first to third bus rings 41 to 43 are arranged parallel to each other in the axial direction and are held by the holder 5. The neutral busbar 44 is held on the radial inner side of the holder 5.

[0027] The first bus ring 41 thus comprises in one piece several holding sections 410, which are held by the holding elements 50 of the holder 5, several connecting sections 411, which are arranged between the several holding sections 410 and are connected to the end sections 321U of the U-phase windings 32U, and the power supply section 412, which is designed to be upright in the axial direction.

[0028] The second bus ring 42 thus comprises several holding sections 420, which are held by the holding elements 50 of the holder 5, several connecting sections 421, which are arranged between the several holding sections 420 and are connected to the end sections 321V of the V-phase windings 32V, and the power supply section 422, which is designed to be upright in the axial direction.

[0029] The third bus ring 43 thus comprises in one piece several holding sections 430, which are held by the holding elements 50 of the holder 5, several connecting sections 431, which are arranged between the several holding sections 430 and are connected to the end sections 321W of the W-phase windings 32W, and the power supply section 432, which is designed to be upright in the axial direction.

[0030] The neutral busbar 44 thus has in one piece an annular section 440, which is formed in a ring shape, and several connecting sections 441, which extend radially from the annular section 440 and are each connected to the other end sections 322U, 322V and 322W of the U, V and W phase windings 32U, 32V and 32W.

[0031] Each of the first to third bus rings 41 to 43 has a ring shape formed by bending an insulated wire 400 in which a wire-like center conductor 400a is covered with insulation 400b. At sections of the connecting sections 411, 421, or 431 that are to be connected to end sections of the windings 32 (the end sections 321U of the U-phase windings 32U, the end sections 321V of the V-phase windings 32V, or the end sections 321W of the W-phase windings 32W), the insulation 400b of the insulated wire 400 is removed, and the center conductor 400a is exposed. The insulated wire 400 is an aspect of a "single continuous wire-like conductor" of the invention.

[0032] The first bus ring 41 is formed by bending an insulated wire 400 such that the multiple held sections 410 and the multiple connecting sections 411 are arranged in a ring. Similarly, the second bus ring 42 is formed by bending an insulated wire 400 such that the multiple held sections 420 and the multiple connecting sections 421 are arranged in a ring. Furthermore, the third bus ring 43 is formed by bending an insulated wire 400 such that the multiple held sections 430 and the multiple connecting sections 431 are arranged in a ring.

[0033] The multiple connection sections 411 of the first bus ring 41 protrude from the holder 5 and are crimped circumferentially to the end sections 321U of the windings 32U. Similarly, the multiple connection sections 421 of the second bus ring 42 protrude from the holder 5 and are crimped circumferentially to the end sections 321V of the windings 32V. Furthermore, the multiple connection sections 431 of the third bus ring 43 protrude from the holder 5 and are crimped circumferentially to the end sections 321W of the windings 32W.

[0034] The neutral busbar 44 is formed by bending a flat conductor element and integrally incorporates the annular section 440 and the multiple connecting sections 441. The annular section 440 of the neutral busbar 44 is formed by bending a strip-shaped material of a predetermined thickness in a radial direction such that both longitudinal ends face each other with a narrow gap between them. The multiple connecting sections 441 of the neutral busbar 44 are arranged at equal intervals along the circumferential direction of the annular section 440 and are formed at an axial end face of the annular section 440 such that they project radially inwards.

[0035] The neutral busbar 44 is held on the inside of the holder 5, while its diameter is elastically reduced, thus narrowing the gap between the two longitudinal ends of the annular section 440. A restoring force of the neutral busbar 44 pushes the holder 5 radially outwards from the inside.

[0036] Fig. Figures 6A to 6D show an exemplary configuration of the retaining element 50 of the holder 5, wherein Fig. 6A is a perspective view, Fig. 6B is a top view, Fig. 6C is a cross-sectional view that is on a line AA of Fig. 6B is taken, and Fig. 6D is a partially enlarged view showing a circumferential end of the retaining element 50, which is in Fig. Figure 6B shows the first bus ring 41 and the neutral bus bar 44. Fig. 6B and Fig. 6D is represented by a double-dotted line, and the first to third bus rings 41 to 43 are in Fig. 6C is represented by a double-dotted line.

[0037] Each of the multiple retaining elements 50 of the holder 5 is formed, for example, by injection molding using an insulating material such as a resin, and thus integrally comprises a first retaining section 51 for holding the first to third bus rings 41 to 43 and second retaining sections 52 for holding the neutral bus bar 44. In the present embodiment, six retaining elements 50 are arranged along the circumferential direction of the first to third bus rings. However, the number of retaining elements 50 is not limited to this and can be three to five or at least seven.

[0038] As in Fig. Figure 6A shows the first to third retaining grooves 50a, 50b and 50c for holding the multiple bus rings 41 to 43 on the first retaining section 51 of each retaining element 50, in order to open on the outside of the holder. The first to third retaining grooves 50a, 50b and 50c extend circumferentially and are radially recessed inwards.

[0039] As in Fig. As shown in Figure 6B, the first holding section 51 of the holding element 50 is curved along the circumferential direction to correspond to the circumferential curvature of the holding sections 410, 420, and 430 of the first to third bus rings 41 to 43. The second holding sections 52 are arranged at equal intervals along the circumferential direction on the inner circumferential surface of the holder 5, which consists of the multiple holding elements 50, and each connecting section 441 of the neutral busbar 44 is arranged between a pair of circumferentially adjacent second holding sections 52.

[0040] The first retaining section 51 of the retaining element 50 has an inner wall section 510 extending in the circumferential direction of the holder 5 and several projecting wall sections 511 extending outwards from the inner wall section 510. In the present embodiment, the retaining element 50 has four projecting wall sections 511 arranged parallel to one another at equal intervals in the axial direction. The three retaining grooves 50a, 50b, and 50c for holding the retained sections 410, 420, and 430 of the first to third bus rings 41 to 43 are formed between the pairs of axially adjacent projecting wall sections 511. The retaining grooves 50a, 50b, and 50c are U-shaped in cross-section and open on the outside of the holder 5.

[0041] The second retaining section 52 has a projecting section 520, which extends radially inward from an inner circumferential surface 510a of the inner wall section 510 of the first retaining section 51, and a locking section 521, which extends axially from an inner end section of the projecting section 520. A gap is formed between the locking section 521 and the inner wall section 510, and the annular section 440 of the neutral busbar 44 is held in the gap. In the present embodiment, a retaining element 50 has four second retaining sections 52, two of which are provided at both circumferential edges of the inner wall section 510 and the other two are provided between them, so that the four second retaining sections 52 are arranged at equal intervals. In this respect, the number of second retaining sections 52 is not limited.For example, a second retaining section 52 can be formed in the circumferential direction on the entire inner circumferential surface 510a of the inner wall section 510.

[0042] The inner wall section 510 of the retaining element 50 is designed such that both ends project beyond the multiple projecting wall sections 511 and the second retaining sections 52 in the circumferential direction of the holder 5. More precisely, when considering the retaining element 50 in the axial direction, as shown in Fig. As shown in Figure 6D, each circumferential end of the retaining element 50 is formed in a V-shape with a corner 500a as a point in the circumferential direction, and the corner 500a is provided on the inner wall section 510. That is, each circumferential end surface of the retaining element 50 is formed from a pair of inclined surfaces 500b and 500c, which are inclined with respect to the radial direction and extend in opposite directions from the corner 500a, which is a section of the inner wall section 500. The inclined surface 500b, which is located on the inside of the corner 500a, and the inclined surface 500c, which is located on the outside of the corner 500a, are inclined in opposite directions relative to the radial direction of the retaining element 5.

[0043] The inclined surface 500c, located on the outside of corner 500a, has circumferential end surfaces of the four projecting wall sections 511. The circumferential length of the projecting wall section 511 decreases towards the front edge (outwards). Meanwhile, the inclined surface 500b, located on the inside of corner 500a, is partially located on the second retaining section 52 at both circumferential ends of the inner wall section 510.

[0044] Fig. Figure 6D shows one of the two circumferential ends of the retaining element 50, and the other end is symmetrical. Furthermore, the six retaining elements 50 that form the holder 5 all have the same shape. When the six retaining elements 50 are arranged circumferentially to form the holder 5, the respective corners 500a of the retaining elements 50 face each other.

[0045] Next, a method for manufacturing the electric motor 1 is described with reference to Fig. The electric motor 1 is manufactured by a method in which a bus ring assembly step, a retaining element assembly step, a neutral busbar assembly step, a bus ring connection step, and a busbar connection step are performed in that order. In the bus ring assembly step, the first to third bus rings 41 to 43 are arranged parallel to each other along the axial direction. In the retaining element assembly step, the multiple retaining elements 50 are displaced from the inside out with respect to the first to third bus rings 41 to 43, which are arranged parallel in the axial direction, so that the retained sections 410, 420, and 430 of the first to third bus rings 41 to 43 are each received in the retaining grooves 50a to 50c.In the neutral busbar assembly step, the neutral busbar 44 is positioned so that it is held by the second retaining sections 52 of the multiple retaining elements 50. In the bus ring connection step, the first to third bus rings 41 to 43 with the windings 32U, 32V and 32W are connected circumferentially by crimping the multiple connecting sections 411, 421 and 431. In the busbar connection step, the neutral busbar 44 with the windings 32U, 32V and 32W is connected by crimping the multiple connecting sections 441.

[0046] Fig. Figure 7 is an explanatory illustration that depicts the retaining element arrangement step in the method for manufacturing the electric motor 1 and shows how the last piece of the several retaining elements 50 is to be attached.

[0047] In the retaining element arrangement step, the holder 5 is formed by sequentially attaching the six retaining elements 50 to the first to third bus rings 41 to 43. Fig. Figure 7 shows the movement paths of the corners 500a at both ends of the last retaining element 50 to be attached, indicated by double-dotted lines S1 and S2. Since the circumferential ends of each retaining element 50 are formed in a V-shape with the corner 500a as the apex in the circumferential direction, as described above, it is possible to attach the six retaining elements 50 to the first to third bus rings 41 to 43 without contact between the last retaining element 50 to be attached and the other retaining elements 50 already attached.

[0048] Once all six retaining elements 50 are attached to the first to third bus rings 41 to 43, the respective corners 500a of the retaining elements 50 face each other in the circumferential direction of the holder 5. At the point where the retaining element arrangement step is completed, at least one pair of circumferentially adjacent retaining elements 50 among the six has a gap between their respective corners 500a. This means that the diameter of the holder 5, which consists of the six retaining elements 50, is larger at the point where the retaining element arrangement step is completed than it would be if all adjacent corners 500a of the retaining elements 50 were in contact with each other.

[0049] In the assembly step for the neutral busbar, the neutral busbar 44 is displaced axially relative to the holder 5, which was formed in the retaining element assembly step, and the annular section 440 of the neutral busbar 44, which is elastically reduced in diameter, is inserted such that it is clamped between the inner circumferential surfaces 510a of the inner wall sections 510 and the projecting sections 520 of the second retaining sections 52. The neutral busbar 44 is thereby held by the holder 5.

[0050] Fig. 8A and Fig. Figure 8B are explanatory illustrations showing the bus ring connection step in a method for constructing the ring for collecting and distributing electricity 4, wherein Fig. 8A shows a state before crimping the connection section 421 of the second bus ring 42 and Fig. 8B shows a state after crimping.

[0051] In the bus ring connection step, the connection sections 411, 421, and 431 of the first to third bus rings 41 to 43 are crimped and connected to the windings 32. Although only the connection section 421 of the second bus ring 42, which is crimped, is shown as an example in Fig. 8A and Fig. As shown in Figure 8B, the connecting sections 411 and 431 of the first and third bus rings 41 and 43 are also crimped in the same way.

[0052] Each connecting section 421 of the second bus ring 42 integrally comprises a first and a second curved section 421a and 421b, which are curved to project radially outward from the held section 410; a first and a second wave section 421c and 421d, which each extend linearly outward from the tip sections of the first and second curved sections 421a and 421b; and an arc section 421e, which has an arc shape and couples between the respective tip sections of the first and second wave sections 421c and 421d. The insulation 400b covers the base end sections of the first and second wave sections 421c and 421d (end sections on the side of the first and second curved sections 421a and 421b).Before crimping the connecting section 421, the first and second curved sections 421a and 421b are not in contact with each other, and the first and second wave sections 421c and 421d are also not in contact with each other.

[0053] The second bus ring 42 is electrically connected to the V-phase winding 32V by crimping the connecting section 421 onto the end section 321V of the winding 32V, which is inserted through it. The end section 321V of the winding 32V is positioned between the first and second shaft sections 421c and 421d. In the present embodiment, the connection is made by thermal crimping (fusion). That is, the connecting section 421 is crimped to the end section 321V of the inserted winding under heat, thereby electrically connecting the second bus ring 42 to the V-phase winding 32V. Since the connecting section 421 is pre-plated with tin, the plated tin is melted by heat, creating a reliable electrical connection.

[0054] The details of the thermal crimping are as follows: A positive electrode 81 is brought into contact with the first wave section 421c of the connection section 421, and a negative electrode 82 is brought into contact with the second wave section 421d of the connection section 421. A DC voltage is applied between the positive electrode 81 and the negative electrode 82, while the first and second wave sections 421c and 421d are pressed by the positive electrode 81 and the negative electrode 82 against the end section 321V of the V-phase winding 32V. This causes the first and second wave sections 421c and 421d to come into contact with the end section 321V of the winding 32V, as shown in Fig. Figure 8B shows how a direct current can flow from the positive electrode 81 to the negative electrode 82 via the first wave section 421c of the connecting section 421, the end section 321V of the winding 32V, and the second wave section 421d. The resulting Joule heat then melts the plated tin and subsequently partially melts the first and second wave sections 421c and 421d of the connecting section 421, as well as the end section 321V of the V-phase winding 32V. The connecting section 421 of the second bus ring 42 is thereby connected to the end section 321V of the V-phase winding 32V.

[0055] Since the first and second curved sections 421a and 421b come into contact with each other due to thermal crimping, the diameter of the second bus ring 42 is slightly reduced. In the bus ring joining step, because all joining sections 411, 421, and 431 of the first to third bus rings 41 to 43 are thermally crimped in the same manner as described above, the diameters of the first to third bus rings 41 to 43 are gradually reduced as the bus ring joining step progresses.

[0056] The gaps between the multiple retaining elements 50 of the holder 5 are narrowed due to the diameter reduction of the first to third bus rings 41 to 43, and as soon as the diameters of the first to third bus rings 41 to 43 are reduced by more than a predetermined amount, adjacent retaining elements 50 abut each other at the respective corners 500a, as shown in Fig.As shown in Figure 8B, the gaps between the retaining elements 50 are no longer narrowed, and thus the diameter of the holder 5 is no longer reduced. This limits any further diameter reduction of the first to third bus rings 41 to 43 by the holder 5. In other words, in the bus ring connection step, any diameter reduction of the first to third bus rings 41 to 43 caused by thermal crimping of the connection sections 411, 421, and 431 is limited by contact between the multiple retaining elements 50 in the circumferential direction.

[0057] In the busbar connection step, the several connection sections 441 of the neutral busbar 44 are crimped and connected to the other end sections 322U, 322V and 322W of the U-, V- and W-phase windings 32U, 32V and 32W. This completes the electric motor 1. Functions and effects of the embodiments

[0058] In the present embodiment, the following functions and effects are obtained. (1) The diameter reduction of the first to third bus rings 41 to 43 during the bus ring connection step is limited by contact between the multiple retaining elements 50 in the circumferential direction. This prevents the connection sections 411, 421 and 431 and the other end sections 322U, 322V and 322W of the windings 32U, 32V and 32W from becoming misaligned during the bus ring connection step, thus preventing an increase in working time. (2) The inner wall section 510 of the retaining element 50 is configured such that both ends project circumferentially beyond the projecting wall sections 511, and each circumferential end of the retaining element 50 is formed in a V-shape, the apex of which in the circumferential direction is the corner 500a located on the inner wall section 510. This configuration prevents contact between the last retaining element 50 to be fastened and the other retaining elements 50 during the retaining element placement step and improves workability at the time of fastening. Additionally, even if the retainer 5 is contracted due to the reduction in diameter of the first to third bus rings 41 to 43, the associated force acts on the relatively high-strength inner wall sections 510 and not on the multiple projecting wall sections 511. Therefore, damage to or deformation of the retainer 5 is prevented. (3) Since the neutral busbar 44 is held inside the holder 5 while its diameter is elastically reduced during the bus ring connection step, a restoring force of the neutral busbar 44 can help prevent a diameter reduction of the first to third bus rings 41 to 43 caused by thermal crimping. In other words, it is possible to further improve the effect described above (1). Summary of embodiments

[0059] Technical concepts that become clear from the embodiment described above are described below with reference to the reference numerals used for that embodiment. However, each reference numeral etc. described below is not intended to limit the constituent elements in the claims to those elements as specifically described in the embodiment. [1] A ring for collecting and distributing electricity (4) for collecting and distributing multiphase currents with different phases from / to several windings (32U, 32V, 32W), wherein the ring for collecting and distributing electricity (4) comprises: several bus rings (41 to 43) provided for the respective phases and arranged parallel to each other along an axial direction, and an annular holder (5) for holding the several bus rings (41 to 43), wherein the holder (5) comprises several separate arcuate retaining elements (50), wherein several retaining grooves (50a, 50b, 50c) for holding the several bus rings (41 to 43) are formed on the several retaining elements (50) such that they open on the outside of the holder (5), wherein each of the several bus rings (41 to 43) is formed by bending a single continuous wire-like conductor such that several held sections (410, 420, 430), which are to be held by the holder (5),and several connecting sections (411, 421, 431) arranged in a ring shape between the several held sections (410, 420, 430) and connected to the windings (32U, 32V, 32W), wherein the connecting sections (411, 421, 431) project outwards from the holder (5) in order to be connected to the windings (32U, 32V, 32W) by crimping in a circumferential direction, and wherein a reduction in the diameter of the several bus rings (41 to 43) by crimping is limited by a contact between the several held sections in the circumferential direction. [2] The ring for collecting and distributing electricity (4) described in [1], wherein each of the several retaining elements (50) comprises an inner wall section (510) extending in the circumferential direction of the holder (5) and several projecting wall sections (511) extending outwards from the inner wall section (510), retaining grooves (50a, 50b, 50c) being formed between the several projecting wall sections (511), both circumferential ends of the inner wall section (510) projecting beyond the several projecting wall sections (511) in a circumferential direction, and the holder (5) being designed such that the inner wall sections (510) of the several retaining elements (50) come into contact with each other by crimping. [3] The ring for collecting and distributing electricity (4) described in [1] or [2], further comprising: an annular neutral conductor (44) connected to end sections (322U, 322W, 322W) of the multiple windings (32U, 32V, 32W), which are the end sections opposite the end sections (321U, 321V, 321W) connected to the multiple bus rings (41 to 43), wherein the annular conductor (44) is held on the inside of the holder (5) while being elastically reduced in diameter. [4] Electric motor (1) comprising: the ring for collecting and distributing electricity (4) described in one of [1] to [3]; a stator (3) capable of generating a rotating magnetic field by electric currents; windings (32U, 32V, 32W); and a rotor (2) which is rotated by the rotating magnetic field relative to the stator (3). [5] Method for manufacturing an electric motor (1) comprising a rotor (2), a stator (3) capable of generating a magnetic field to rotate the rotor (2) by means of electric currents flowing through windings (32), and a ring for collecting and distributing electricity (4) for collecting and distributing multiphase currents with different phases from / to the (32U, 32V, 32W), wherein the ring for collecting and distributing electricity (4) comprises several bus rings (41 to 43) provided for the respective phases and arranged parallel to each other along an axial direction, and an annular holder (5) for holding the several bus rings (41 to 43), wherein the holder (5) comprises several separate arc-shaped retaining elements (50), wherein several retaining elements (50a, 50b, 50c) for holding several bus rings (41 to 43) on the several retaining elements (50) are configured such that they open on the outside of the holder (5), wherein each of the several bus rings (41 to 43) is configured by bending a single continuous wire-shaped conductor such that several held sections (410, 420, 430) to be held by the holder (5) and several connecting sections (411, 421, 431) to be connected between the several held sections (410, 420, 430) are arranged and are connected to the windings (32U, 32V, 32W),are arranged in a ring shape, and the connecting sections (411, 421, 431) protrude outwards from the holder (5) in order to be connected to the windings (32U, 32V, 32W) by crimping in a circumferential direction, wherein the method comprises: arranging the multiple bus rings (41-43) parallel to each other along an axial direction; arranging the multiple retaining elements (50) by sliding them from the inside towards the outside relative to the multiple bus rings (41 to 43), such that the retained sections (410, 420, 430) of the multiple bus rings (41 to 43) are each received in the multiple retaining grooves (50a, 50b, 50c); and connecting the multiple bus rings (41 to 43) to the windings (32) by crimping the connecting sections (411, 421, 431) in a circumferential direction, wherein the diameter reduction of the multiple bus rings (41 to 43) by crimping is limited at the time of connection by a contact between the multiple retaining sections in the circumferential direction.

[0060] Although the embodiment of the invention has been described, the invention is not limited to this embodiment according to the claims. Furthermore, it should be noted that not all combinations of the features described in the embodiment are necessary to solve the problem of the invention.

[0061] In addition, the invention can be suitably modified and implemented without deviating from its core. Although, for example, the circumferential end surfaces of all retaining elements 50 in the embodiment are formed in a V-shape with the corner 500a as the apex, the invention is not limited thereto. Perhaps only the last retaining element 50, which is to be fastened in the retaining element arrangement step, needs to be formed to have such a shape. However, if all of the several retaining elements 50 have the same shape as in the embodiment, the same component can be used together, and it is therefore possible to reduce manufacturing costs.

Claims

Ring for collecting and distributing electricity (4) for collecting and distributing multiphase currents with different phases from / to several windings (32U, 32V, 32W), comprising: several bus rings (41, 42, 43) provided for the respective phases and arranged parallel to each other along an axial direction, and an annular holder (5) for holding the several bus rings, the holder comprising several separate arcuate retaining elements (50), wherein several retaining grooves (50a, 50b, 50c) for holding the several bus rings on the several retaining elements are formed such that they open on the outside of the holder, each of the several bus rings being formed by bending a single continuous wire-shaped conductor such that several held sections (410, 420, 430) to be held by the holder and several connecting sections (411, 421, 431) are formed.which are arranged between the several held sections and are connected to the windings, are arranged in a ring shape, wherein the connecting sections (411, 421, 431) project outwards from the holder in order to be connected to the windings by crimping in a circumferential direction, and wherein a diameter reduction of the several bus rings by crimping is limited by a contact between the several holding sections in the circumferential direction, wherein each of the several holding elements comprises an inner wall section (510) extending in the circumferential direction of the holder (5) and several projecting wall sections (511) extending outwards from the inner wall section (510), wherein the holding grooves (50a, 50b, 50c) are formed between the several projecting wall sections (511), wherein both circumferential ends of the inner wall section (510) project beyond the several projecting wall sections (511) in a circumferential direction.and wherein the holder (5) is designed such that the inner wall sections (510) of the several retaining elements (50) come into contact with each other through crimping. Ring for collecting and distributing electricity according to claim 1, further comprising: an annular neutral conductor (44) connected to end sections (322U, 322W, 322W) of the multiple windings (32U, 32V, 32W), which are the end sections opposite end sections (321U, 321V, 321W) connected to the multiple bus rings, wherein the annular conductor (44) is held on the inside of the holder while being elastically reduced in diameter. Electric motor comprising: the ring for collecting and distributing electricity according to claim 1 or 2; a stator (3) capable of generating a rotating magnetic field by electric currents flowing through the multiple windings; and a rotor (2) rotated relative to the stator by the rotating magnetic field. Method for manufacturing an electric motor (1) comprising a rotor (2), a stator (3) capable of generating a magnetic field to rotate the rotor by means of electric currents flowing through windings (32), and a ring for collecting and distributing electricity (4) for collecting and distributing multiphase currents with different phases from / to the winding(s) (32U, 32V, 32W), wherein the ring for collecting and distributing electricity comprises several bus rings (41, 42, 43) provided for the respective phases and arranged parallel to each other along an axial direction, and an annular holder (5) for holding the several bus rings, wherein the holder comprises several separate arcuate retaining elements (50), wherein several retaining grooves (50a, 50b, 50c) for holding the several bus rings on the several retaining elements (50) are configured such that they open on the outside of the holder (5).wherein each of the multiple bus rings is formed by bending a single continuous wire-shaped conductor such that multiple held sections (410, 420, 430) to be held by the holder and multiple connecting sections (411, 421, 431) arranged between the multiple held sections and connected to the windings (32U, 32V, 32W) are arranged in a ring shape, the connecting sections (411, 421, 431) projecting outwards from the holder to be connected to the windings (32U, 32V, 32W) by crimping in a circumferential direction, the method comprising: arranging the multiple bus rings parallel to each other along an axial direction, arranging the multiple retaining elements (50) by sliding them from the inside towards the outside relative to the multiple bus rings arranged in parallel, such that the held sections of the multiple bus rings are each in the multiple retaining grooves (50a, 50b,50c); and connecting the multiple bus rings to the windings (32) by crimping the connecting sections (411, 421, 431) in a circumferential direction, wherein the diameter reduction of the multiple bus rings by crimping at the time of connection is limited by contact between the multiple retaining sections in the circumferential direction, wherein each of the multiple retaining elements comprises an inner wall section (510) extending in the circumferential direction of the holder and multiple projecting wall sections extending outwards from the inner wall section, wherein the retaining grooves (50a, 50b, 50c) are formed between the multiple projecting wall sections (511), wherein both circumferential ends of the inner wall section (510) project beyond the multiple projecting wall sections (511) in a circumferential direction, and wherein the holder (5) is designed such thatthat the inner wall sections (510) of the several retaining elements (50) come into contact with each other through crimping.

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