Busbar unit and brushless motor

Abstract

In the bus bar unit (4), the holder (20) covering the plurality of bus bars (30) has a ring-shaped region (R) in a plane (P) orthogonal to the axis (C). Each bus bar (30) is disposed within the ring-shaped region (R), the centers of the arcs are offset from each other, and a portion of each bus bar (30) overlaps other bus bars (30) within a prescribed angular range of the ring-shaped region (R). Alternatively, the bus bar unit (4) of the inner rotor type brushless motor (1) has the holder (20) placed on the stator (3) and a plurality of bus bars (30) that wire the coils (16) of the three phases of the stator (3) in the same phase. Each bus bar (30) is disposed extending along the circumferential direction, and is covered by the holder (20) at the same position in the axial direction. In addition, a first portion (31) of each bus bar (30) is located radially inward of a second portion (32) of the bus bar (30), and overlaps the second portion (32) of the other bus bar (30) when viewed in the radial direction.

Description

Technical Field

[0001] This application relates to a busbar unit and a brushless motor having the busbar unit. Background Technology

[0002] Conventionally, brushless motors are known to use conductive busbars to wire the windings of multiple coils disposed on the stator. For example, Patent Document 1 discloses a brushless motor having a wiring busbar (busbar unit) having multiple conductive plates (here, the busbar) for wire the windings of multiple coils and an insulating member housing these conductive plates in an axially stacked state.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent No. 7280070 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] However, in the brushless motor of Patent Document 1, which has multiple busbars stacked axially, space needs to be ensured inside the motor for arranging the stacked busbars. There is room for improvement if the motor size does not need to be increased axially. It should be noted that the above-mentioned problem arises when multiple busbars are provided in the busbar unit, and is not limited to the case where the component connected through the busbar is the motor coil, nor is it limited to the case where the device providing the busbar unit is a motor.

[0008] This application is made in view of such a problem, and one of its objectives is to provide a busbar unit capable of suppressing the expansion of the size of a device equipped with a busbar unit, and a brushless motor equipped with the busbar unit. It should be noted that this application is not limited to this objective, and another objective is to achieve the effects derived from the various structures shown in the specific embodiments described later, and effects that cannot be obtained by conventional technology.

[0009] Solution for solving the problem

[0010] The busbar unit and brushless motor disclosed herein can be implemented as the solutions (application examples) disclosed below, solving at least a portion of the aforementioned problems.

[0011] Solution 1. The busbar unit of this disclosure comprises a plurality of arc-shaped busbars and a retainer covering the plurality of busbars and forming an annular shape around an axis. The retainer has an annular region in a plane orthogonal to the axis, centered on the axis and having a predetermined radial width. Each of the busbars is disposed within the annular region, and the centers of the arcs are staggered from each other. At least a portion of each busbar overlaps with other busbars within a predetermined angle range in the annular region.

[0012] Option 2. Another busbar unit disclosed herein is a busbar unit for an inner rotor type brushless motor having an annular stator and a rotor located radially inward on the inner side of the stator. This busbar unit has a resin retainer mounted on a predetermined axial side of the stator and multiple conductive busbars for connecting the three-phase coils of the stator in phase. Each busbar extends circumferentially along the stator and is covered by the retainer at the same position in the axial direction relative to the retainer. A first portion at one end of the circumferential direction is located closer to the inner side than a second portion at the other end of the circumferential direction. The first portion of each busbar overlaps with the second portion of any other busbar when viewed radially.

[0013] Solution 3. The brushless motor disclosed herein comprises: a busbar unit including Solution 2 above; a stator on which the busbar unit is mounted; and a rotor that rotates integrally with the shaft on the inner side of the stator.

[0014] Invention Effects

[0015] According to the invention disclosed herein, it is possible to provide a busbar unit that can suppress the expansion of the size of a device in which the busbar unit is provided, and it is also possible to provide a brushless motor incorporating the busbar unit. Attached Figure Description

[0016] Figure 1 This is an exploded perspective view of a brushless motor that utilizes the busbar unit described in the implementation method.

[0017] Figure 2 yes Figure 1 A 3D diagram of the stator of a brushless motor.

[0018] Figure 3 It schematically shows the formation set in Figure 2 The diagram shows the wiring method and connection method of the stator coil winding.

[0019] Figure 4It is a diagram used to illustrate the characteristics of the starting and ending wires of the winding, and is a perspective view showing a part of the stator core unit and the winding wound on that part.

[0020] Figure 5 From the first axis Figure 1 A three-dimensional image obtained by observing the first busbar unit and stator of a brushless motor.

[0021] Figure 6 yes Figure 5 XX-direction sectional view of the first busbar unit.

[0022] Figure 7 Therefore, plane P will Figure 6 The axial cross-sectional view obtained by cutting the first busbar unit.

[0023] Figure 8 From the second axis Figure 5 The three-dimensional image obtained when observing the first busbar unit.

[0024] Figure 9 From the second axis Figure 1 A three-dimensional image obtained by observing the second busbar unit and stator of the brushless motor. Detailed Implementation

[0025] Referring to the accompanying drawings, the busbar unit and brushless motor as embodiments will be described. The embodiments shown below are merely illustrative and are not intended to exclude various modifications and technical applications not explicitly shown in the following embodiments. The structures of this embodiment can be modified and implemented in various ways without departing from its spirit.

[0026] The busbar unit comprises multiple arc-shaped busbars and a retainer covering these busbars and arranged in a ring around an axis. The retainer has an annular region with a predetermined radial width centered on the axis in a plane orthogonal to the axis. Each busbar is disposed within the annular region of the retainer, with the centers of the arcs offset from each other, and at least a portion of each busbar overlaps with other busbars within a predetermined angle range of the annular region. This structure allows multiple busbars to be arranged in a manner that does not overlap in the axial direction, thus suppressing the expansion of the size (especially the axial dimension) of the device equipped with the busbar unit. The busbar unit described in detail below is applied as an example to a brushless motor, but its application is not limited to motors; it can also be used in various electrical devices such as switchboards, batteries, and generators.

[0027] Alternatively, the busbar unit can also be applied to an internal rotor type brushless motor. In this case, the busbar unit includes a resin retainer mounted on a predetermined axial side of the stator of the brushless motor and multiple conductive busbars that connect the three-phase coils provided on the stator in the same phase. Each busbar extends circumferentially and is covered by the retainer at the same axial position relative to the retainer, with a first portion on one end of the circumferential direction located radially inward than a second portion on the other end of the circumferential direction. Furthermore, the first portion of each busbar overlaps with the second portion of any other busbar when viewed radially. With this structure, multiple busbars can be arranged in a manner that does not overlap axially, thus suppressing the expansion of the size (especially the axial size) of the brushless motor equipped with the busbar unit. In addition, the first and second portions of each busbar can be extended to the vicinity of the coil connected to the busbar, thus preventing the winding of the coil connected through the busbar from becoming complicated.

[0028] [1. Structure]

[0029] [1-1. Overall Structure]

[0030] Figure 1 This is an exploded perspective view of a brushless motor 1 (hereinafter also referred to as "motor 1") using the busbar unit according to this embodiment. The brushless motor 1 according to this embodiment is an internal rotor type brushless motor, such as... Figure 1 As shown, it includes a rotor 2, a stator 3, and busbar units 4 and 5 that rotate integrally with the shaft 1s. The motor 1 is constructed by housing the rotor 2, stator 3, and busbar units 4 and 5 within a bottomed cylindrical housing 6. An end cover 7, serving as a cover member, can be assembled on the open side (left side in the figure) of the housing 6.

[0031] Hereinafter, the direction of extension of shaft 1s (the direction of the axis C of shaft 1s) will be referred to as the axial direction. The direction in which the bottom of housing 6 is located relative to the opening of housing 6 will be defined as the axial direction. Figure 1 The direction on the right side of the diagram is called the first axis Da1 (defined axis), and the direction opposite to the first axis Da1 is called the second axis Da2. The direction orthogonal to the axis and away from axis C, as well as the direction towards axis C, are called radial. The radial direction away from axis C is called the radial outer direction (outer direction), and the direction towards axis C is called the radial inner direction (inner direction). The direction orthogonal to the axis and surrounding axis C is called the circumferential direction. The circumferential direction that is clockwise when viewed from the first axis Da1 side is called the first circumferential direction Dc1, and the direction opposite to the first circumferential direction Dc1 (counterclockwise direction) is called the second circumferential direction Dc2.

[0032] The motor 1 illustrated here has the following features: Figure 1Two busbar units 4 and 5 are arranged axially to clamp the stator 3 as shown. Hereinafter, the busbar unit 4 located on the first axial direction Da1 side of the stator 3 will be referred to as the first busbar unit 4, and the busbar unit 5 located on the second axial direction Da2 side of the stator 3 will be referred to as the second busbar unit 5. The first busbar unit 4, the stator 3, and the second busbar unit 5 are arranged in this order from the first axial direction Da1 toward the second axial direction Da2, and are housed in the housing 6. The rotor 2 and the shaft 1s pass through the stator 3 and the two busbar units 4 and 5 radially inside. The busbar unit involved in this embodiment is set as (applied as) the first busbar unit 4.

[0033] [1-2. Rotor]

[0034] The rotor 2, for example, has a rotor core that rotates integrally with the shaft 1s and multiple magnets embedded in the rotor core. The shaft 1s is the rotating shaft that supports the rotor 2 and also functions as an output shaft that extracts the output (mechanical energy) of the motor 1 to the outside. The shaft 1s is rotatably supported by the bottom and end cover 7 of the housing 6, for example, via bearings 8 that clamp the two parts of the rotor core in the axial direction.

[0035] [1-3. Stator]

[0036] The stator 3 is an annular component with a space for arranging the rotor 2 on its radially inner side, and it is concentrically arranged with the axis C. Therefore, the axial, radial, and circumferential directions of the aforementioned axis C can also be referred to as the axial, radial, and circumferential directions of the stator 3, respectively. The stator 3 in this embodiment has an annular (cylindrical) shape, but the shape of the stator 3 is not limited to this.

[0037] like Figure 2 As shown, the stator 3 has a generally cylindrical core unit 11 and a plurality of coils 16. The core unit 11 is, for example, configured as an embedded molded article formed by molding a stator core 11c made of multiple steel plates of the same shape stacked with resin that serves as an insulator 11i, and is fixed inside the housing 6.

[0038] The core unit 11 has a cylindrical outer peripheral wall 12, a plurality of teeth 13 protruding radially inward from the inner peripheral surface of the outer peripheral wall 12, and an arc-shaped inner peripheral wall 14 extending circumferentially inward on the radially inward side of each tooth 13. The plurality of teeth 13 are circumferentially separated from each other and are arranged at equal intervals. Slots 15, the same number as the teeth 13, are formed between the plurality of teeth 13. The coil 16 is formed by winding a wire W around the plurality of teeth 13 respectively, and is configured to be the same number as the teeth 13.

[0039] It should be noted that in the core unit 11, the insulating member 11i only needs to insulate the stator core 11c from the coil 16, and it may not need to cover the entire outer surface of the stator core 11c. For example, in the outer peripheral wall 12, the insulating member 11i may not cover the outer peripheral surface of the stator core 11c. The outer peripheral surface of the stator core 11c may be positioned radially outward from the outer peripheral surfaces of the insulating members 11i located on both sides of its axial direction, as shown in the figure. In other words, steps formed by the stator core 11c and the insulating member 11i may also be provided on both sides of the outer peripheral surface of the outer peripheral wall 12 in the axial direction. These steps can be used to mount the retaining member 20 of the first busbar unit 4, described later, on the stator 3.

[0040] like Figure 2 as well as Figure 3 As shown, in this embodiment, the stator 3 is provided with twelve teeth 13, twelve slots 15, and twelve coils 16. The stator 3 is also provided with four U-phase coils 16u, four V-phase coils 16v, and four W-phase coils 16w, totaling twelve coils 16. U-phase current is supplied to the U-phase coil 16u, V-phase current is supplied to the V-phase coil 16v, and W-phase current is supplied to the W-phase coil 16w.

[0041] It should be noted that, in Figure 2 In the diagram, only two adjacent teeth 13 in the circumferential direction out of the twelve teeth 13 are shown using dashed lines. Additionally, only one groove 15 out of the twelve grooves, formed between the two teeth 13 shown, is labeled with a reference numeral. Figure 3 In the figure, only a portion of the twelve teeth 13 and the twelve grooves 15 are marked with reference numerals.

[0042] For example, such as Figure 2 As shown, on stator 3, the U-phase coils 16u, V-phase coils 16v, and W-phase coils 16w are arranged in pairs along the circumferential direction. That is, two of the four U-phase coils 16u are arranged adjacent to each other circumferentially, and two V-phase coils 16v are arranged adjacent to each other circumferentially on the second circumferential Dc2 side. Additionally, two W-phase coils 16w are arranged adjacent to each other circumferentially on the second circumferential Dc2 side, and the remaining two U-phase coils 16u are arranged adjacent to each other circumferentially on the second circumferential Dc2 side. The remaining two V-phase coils 16v are arranged adjacent to each other circumferentially on the second circumferential Dc2 side, and the remaining two W-phase coils 16w are arranged adjacent to each other circumferentially on the second circumferential Dc2 side.

[0043] Hereinafter, the two adjacent coils 16 of the same phase will be collectively referred to as coil groups 17. The stator 3 having twelve coils 16 can also be described as having two each of the U-phase coil group 17u, the V-phase coil group 17v, and the W-phase coil group 17w. Furthermore, regarding the above-mentioned arrangement of the coils 16, the U-phase coil group 17u, the V-phase coil group 17v, and the W-phase coil group 17w are arranged circumferentially on the stator 3 in this order, which can also be described as being arranged with two coil groups 17 of each phase facing each other with the axis C between them.

[0044] In this embodiment, such as Figure 3 As shown, each coil group 17 is formed by a single continuous winding wire W. That is, six winding wires W are provided in the stator 3, each winding wire W wound around two adjacent teeth 13 in the circumferential direction, thereby forming each coil group 17. Specifically, the winding wire W forming each coil group 17 is not cut after being wound around one of the two adjacent teeth 13 in the circumferential direction, but is wound around the other side of the two teeth 13. The winding wire W forming each coil group 17 can be arranged (wired) in a manner where the winding direction relative to one tooth 13 is opposite to the winding direction relative to the other tooth 13, as shown in the diagram.

[0045] Each winding W has its starting line Ws and ending line Wf, one of which is drawn towards the first axial direction Da1, and the other is drawn towards the second axial direction Da2. In this embodiment, as... Figure 3 As shown, all the starting wires Ws of the six windings W are led out towards the second axis Da2 side, and all the ending wires Wf of the six windings W are led out towards the first axis Da1 side. The six starting wires Ws led out to the second axis Da2 side are connected to the busbar 50 of the second busbar unit 5 (described later), and the six ending wires Wf led out to the first axis Da1 side are connected to the busbar 30 of the first busbar unit 4 (described later).

[0046] The starting wires Ws of the six starting wires Ws that are drawn towards the second axial direction Da2, forming adjacent coil groups 17, can be drawn from the same (common) slot 15. In this embodiment, two starting wires Ws are drawn from each of the three slots 15 arranged every three circumferentially. Similarly, the ending wires Wf of the six ending wires Wf that are drawn towards the first axial direction Da1, forming adjacent coil groups 17, can be drawn from the same slot 15. In this embodiment, two ending wires Wf are drawn from each of the three slots 15 arranged every three circumferentially. The starting wires Ws and ending wires Wf of each winding W can be drawn from the same slot 15. Figure 3 It can be drawn from different slots 15 as shown, or it can be drawn from the same slot 15.

[0047] It should be noted that the starting wire Ws refers to the portion of the winding W (wire) that forms each coil group 17 at the beginning of the winding, and the ending wire Wf refers to the portion of the winding W (wire) that forms each coil group 17 at the end of the winding. The electricity supplied to each coil group 17 can flow from the starting wire Ws towards the ending wire Wf, or from the ending wire Wf towards the starting wire Ws. Therefore, the starting wire Ws and the ending wire Wf are defined independently of the direction of electricity flow supplied to each coil group 17.

[0048] Figure 4 This is a perspective view showing a portion of a core unit 11 and the winding W wound on that portion, as an example used to illustrate the characteristics of the starting wire Ws and the ending wire Wf of the winding W. Figure 4 In this example, as part of the core unit 11, the core unit 11 is divided into twelve circumferentially, with only one of the twelve divided cores 11n shown. The core unit 11 can be constructed in this way by combining multiple divided cores 11n that are equally spaced circumferentially.

[0049] Furthermore, as described above, in the stator 3 of this embodiment, the following situation applies: by continuously winding a single winding wire W around two adjacent teeth 13, a coil group 17 consisting of two coils 16 of the same phase is formed. However, in Figure 4 The example illustrates a case where a single winding W is wound around a single split core 11n (one tooth) to form a coil 16. The stator 3 can also be configured with the same number of windings W as the number of teeth 13.

[0050] like Figure 4 As shown, the starting wire Ws of the winding W is constrained and fixed by the connecting wire Wc, which connects the starting wire Ws and the ending wire Wf, by winding it around the teeth. Since the starting wire Ws of the winding W forming each coil group 17 is fixed in this way, it has the characteristic that the radial position of the starting wire Ws is less prone to deviation for each coil group 17 (less clearance). On the other hand, the ending wire Wf of the winding W, which is the end of the winding, is not constrained by the connecting wire Wc, and therefore has a high degree of freedom, being led out radially inward or radially outward towards the first axial direction Da1. Due to these characteristics, the starting wire Ws can also be considered the fixed end of the winding W, and the ending wire Wf can also be considered the free end of the winding W.

[0051] [1-4. First busbar unit]

[0052] The first busbar unit 4 is a component mounted on the first axial Da1 side of the stator 3 and connecting the three-phase coils 16 in the same phase, such as... Figure 5As shown, it has a resin retainer 20 and multiple busbars 30. Each busbar 30 is a conductive component that connects the three-phase coils 16 in phase, and is covered by the retainer 20 (embedded in the retainer 20). That is, the first busbar unit 4 is configured as an embedded molded article formed by molding multiple busbars 30 using the resin retainer 20 and components, or the resin retainer 20.

[0053] In this embodiment, the end wires Wf of the two U-phase coil groups 17u, the two V-phase coil groups 17v, and the two W-phase coil groups 17w are led out towards the first axial direction Da1. Therefore, as Figure 3 as well as Figure 5 As shown, the first busbar unit 4 is provided with three busbars 30: a U-phase busbar 30u that connects the end wires Wf of the two U-phase coil groups 17u to each other, a V-phase busbar 30v that connects the end wires Wf of the two V-phase coil groups 17v to each other, and a W-phase busbar 30w that connects the end wires Wf of the two W-phase coil groups 17w to each other.

[0054] The retainer 20 is annular about the axis. In this embodiment, as... Figure 5 As shown, the retaining member 20 is arranged such that its axis is aligned with the axis C of the motor 1 (shaft 1s), and when viewed axially, it appears as an annular ring surrounding the axis C. Figure 5 as well as Figure 6 As shown, a main body 21 can be provided on the retainer 20 to cover the three busbars 30. The main body 21 unfolds in a direction orthogonal to the axis C, and is annular when viewed from the axial direction and flat when viewed from the radial direction.

[0055] like Figure 6 As shown, the three busbars 30 are arranged on a plane P that overlaps with the main body 21 in the axial direction. Figure 7 As shown, the three busbars 30 are arranged on plane P in an annular region R having a predetermined radial width H that is substantially equal to the radial width of the main body 21 (retaining member 20). Figure 7 The area is indicated by light and dark dots. It should be noted that... Figure 7 This is an axial cross-sectional view obtained by observing the first busbar unit 4, which is cut by plane P, from the first axial Da1 side. Figure 7 For convenience, the shaded lines showing the cross-sections of the retainer 20 and the busbars 30 are omitted. The retainer 20 has an annular region R in a plane P orthogonal to the axis C, centered on the axis C and having a defined radial width H. Alternatively, multiple busbars 30 are respectively arranged within this annular region R.

[0056] All three busbars 30 are arc-shaped when viewed from the axial direction. Each busbar 30 can be configured, for example, as follows: Figure 6 As shown, when viewed radially, it appears as a flat plate with uniform thickness in the axial direction, and as... Figure 7 As shown, it appears as an arc-shaped strip when viewed from the axial direction. Each busbar 30 can be configured to have the same radius of curvature ru, rv, rw relative to the center of the arc Cu, Cv, Cw of each busbar 30, the same length of the arc with the center of the arc Cu, Cv, Cw of each busbar 30 as a reference, and the same plate thickness of each busbar 30, and is configured to be three times rotationally symmetric about the axis C.

[0057] Hereinafter, the center of the arc of the U-phase busbar 30u will be referred to as the U-phase busbar center Cu, the center of the V-phase busbar 30v will be referred to as the V-phase busbar center Cv, and the center of the W-phase busbar 30w will also be referred to as the W-phase busbar center Cw. The U-phase busbar centers Cu, V-phase busbar centers Cv, and W-phase busbar centers Cw are staggered from each other. In this embodiment, these busbar centers Cu, Cv, and Cw are equidistant from the axis C, but are arranged at equal intervals around the axis C. In this way, each busbar center Cu, Cv, and Cw is staggered from the axis C, which can also be described as each busbar 30u, 30v, and 30w being eccentric relative to the axis C.

[0058] Each busbar 30 is configured such that a portion of it overlaps radially (is radially adjacent) with other busbars 30 within a specified angle α range centered on axis C in the annular region R. Hereinafter, the local annular (approximately truncated) region in the annular region R in which a portion of each busbar 30 overlaps radially with other busbars 30 at a specified angle α will be described. Figure 7 The area marked with a dark dot is called the specified angle region Rα. The specified angle α for the specified angle region Rα is at least less than the central angle of the arc of each busbar 30, and there is no particular limitation. It is preferred to set it as the angle obtained by dividing 360° by the number of slots 15 of the stator 3 (in this case, 30° obtained by dividing 360° by 12).

[0059] In this embodiment, the circumferential portions on both sides of each busbar 30 are configured as described above, and the circumferential portions on both sides of each busbar 30 are respectively configured to overlap radially with other busbars 30 within a predetermined angle region Rα. Specifically, the first circumferential Dc1 side portion of one of the three busbars 30 (e.g., U-phase busbar 30u) is configured to overlap radially with the second circumferential Dc2 side portion of one of the remaining two busbars 30 (e.g., V-phase busbar 30v) within the predetermined angle region Rα. Furthermore, the second circumferential Dc2 side portion of this one busbar 30 (e.g., U-phase busbar 30u) is configured to overlap radially with the first circumferential Dc1 side portion of the other of the remaining two busbars 30 (e.g., W-phase busbar 30w) within the predetermined angle region Rα. Correspondingly, the three predetermined angle regions Rα are circumferentially separated and equally spaced within the annular region R.

[0060] Hereinafter, the portion of each busbar 30 on the first circumferential Dc1 side will be referred to as the first portion 31, and the portion on the second circumferential Dc2 side will be referred to as the second portion 32. The first portion 31 of each busbar 30 (e.g., U-phase busbar 30u) is located radially inward of the second portion 32 of other busbars 30 (e.g., V-phase busbar 30v) that radially overlap with the first portion 31 within a specified angular region Rα. That is, the three busbars 30 are configured circumferentially to overlap each other radially within a specified angular region Rα, and the first portion 31 and the second portion 32 are different from each other.

[0061] As described above, the centers Cu, Cv, and Cw of the three busbars 30 are staggered, thus enabling this configuration. Furthermore, in the first busbar unit 4, this allows the three busbars 30 to be arranged on the same plane P without overlapping axially. Therefore, the axial thickness of the portion of the retainer 20 covered by these busbars 30 (main body 21) can be reduced, thereby suppressing the expansion of the axial dimensions of the motor 1.

[0062] The structure of the first busbar unit 4 will be described in detail below using different wording than described above.

[0063] In the first bus bar unit 4, the three bus bars 30 are as follows Figure 5 As shown, they do not overlap when viewed from the axial direction, and as Figure 6 As shown, they are positioned axially at the same location relative to the retainer 20, i.e., on the same plane P. Additionally, as... Figure 5As shown, each busbar 30 extends circumferentially, and the first portion 31 on the first circumferential Dc1 side (one end side) is positioned radially inward than the second portion 32 on the second circumferential Dc2 side (the other end side). It should be noted that "extending along..." in this embodiment is not limited to extending in a direction parallel to the reference direction (e.g., circumferential), but also includes extending in a direction inclined relative to the reference direction.

[0064] The first portion 31 of each busbar 30 (e.g., U-phase busbar 30u) and the second portion 32 of any other busbar 30 (e.g., V-phase busbar 30v) are configured to overlap when viewed radially. That is, the first portion 31 of each busbar 30 is configured to overlap with the second portion 32 of other busbars 30 that connect to the coil group 17 of a phase different from the phase connected to that busbar 30 (hereinafter also referred to as "corresponding phase") when viewed radially. It should be noted that "overlapping when viewed radially" is synonymous with being located on a radius line passing through axis C. That is, the configuration of each busbar 30 is set such that when a radius is drawn from axis C through the first portion 31 of a certain busbar 30, the second portion 32 of other busbars 30 is located on that radius line.

[0065] Therefore, the three busbars 30 can be prevented from overlapping axially, and can be as follows: Figure 3 As shown, the first portion 31 and the second portion 32 of each phase busbar 30 (e.g., U-phase busbar 30u) are respectively extended to the vicinity of the two coil groups 17 (e.g., U-phase coil group 17u) of the corresponding phase. Therefore, compared to conventional busbar units that stack multiple busbars axially, the first busbar unit 4 with three busbars 30 can be arranged in a narrower axial space, thereby suppressing the expansion of the axial size of the motor 1. Furthermore, the distance between each phase busbar 30 and the corresponding phase coil group 17 can be shortened, thus allowing the end wire Wf (winding wire W) drawn from the corresponding phase coil group 17 to be joined to each phase busbar 30 in a manner without complex winding.

[0066] For example, such as Figure 3As shown, the first portion 31 and the second portion 32 of each phase busbar 30 can be configured to overlap axially with the slot 15 from which the end wire Wf of the coil group 17 of the corresponding phase is drawn. In this embodiment, as described above, the end wires Wf of the windings W of the coil groups 17 of different phases that are adjacent in the circumferential direction are drawn from three slots 15 arranged every three in the circumferential direction. Therefore, the first portion 31 of the busbar 30 (e.g., U-phase busbar 30u) joined to one of the end wires Wf of the coil groups 17 of different phases that are adjacent in the circumferential direction and the second portion 32 of the busbar 30 (e.g., V-phase busbar 30v) joined to the other end wires Wf of these phases are configured to overlap axially with the common slot 15, and three portions of the first portion 31 and the second portion 32 that are adjacent in the radial direction are provided in the first busbar unit 4.

[0067] The length L of the circumferential overlap between the first portion 31 of each busbar 30 (e.g., U-phase busbar 30u) and the second portion 32 of any other busbar 30 (e.g., V-phase busbar 30v) is (see reference) Figure 7 Preferably, the length of the arc of the sector with a central angle obtained by dividing 360° by the number of slots 15 of the stator 3 is approximately the same as the length of the arc of the sector with a central angle of 30° obtained by dividing 360° by 12. Here, since there are twelve slots 15, the overlap length L of the first part 31 and the second part 32 is set to be approximately the same as the length of the arc of the sector with a central angle of 30° obtained by dividing 360° by 12.

[0068] In this embodiment, the first busbar unit 4 is mounted on the stator 3 such that the three specified angular regions Rα mentioned above overlap with each of the three slots 15 arranged every three circumferentially. This realizes the arrangement relationship of the first part 31 and the second part 32 of each busbar 30 relative to the slot 15, and the relationship of the overlap length L between the first part 31 and the second part 32. In the first busbar unit 4, the first part 31 and the second part 32 of each busbar 30 are respectively arranged to overlap axially with the slot 15 from which the end wire Wf of the coil group 17 of the corresponding phase is led out. This allows the end wire Wf led out from the coil group 17 of each phase to be routed to the busbar 30 of the corresponding phase in a manner that does not involve circumferential winding, thereby further suppressing the complexity of the routing of the end wire Wf.

[0069] like Figure 3As shown, the end wire Wf of the coil group 17 (one of the two coils) located on the first circumferential Dc1 side relative to the busbar 30, connected to the two in-phase coil groups 17 connected to each busbar 30, is engaged with the first portion 31 of the busbar 30. Additionally, the end wire Wf of the coil group 17 (the other of the two coils) located on the second circumferential Dc2 side relative to the busbar 30, connected to the two in-phase coil groups 17 connected to each busbar 30, is engaged with the second portion 32 of the busbar 30.

[0070] Hereinafter, the portion of the first part 31 of each busbar 30 that engages with the winding W of the coil group 17 of the corresponding phase located on the first circumferential Dc1 side of the busbar 30 will be referred to as the first engagement portion 33. Furthermore, the portion of the second part 32 of each busbar 30 that engages with the winding W of the coil group 17 of the corresponding phase located on the second circumferential Dc2 side of the busbar 30 will be referred to as the second engagement portion 34.

[0071] like Figure 5 As shown, the first joint 33 can be located in the first portion 31, except for the first end 35 on the first circumferential Dc1 side. Similarly, the second joint 34 can be located in the second portion 32, except for the second end 36 on the second circumferential Dc2 side. On the radially inner side of the first joint 33 and the radially outer side of the second joint 34, grooves 37 for engaging the end lines Wf that engage with these joints 33 and 34 can be cut from the radially inner side and the radially outer side, respectively.

[0072] It should be noted that in the area (prescribed angle region Rα) where the first part 31 and the second part 32 of the two busbars 30 overlap when viewed radially, the first joint 33 and the second joint 34 can also be as follows: Figure 5 As shown, portions arranged circumferentially repeat each other when viewed radially. In this region, the first portion 31 and the second portion 32 may also be circumferentially integral and not repeat when viewed radially. Additionally, in this region, the circumferential positions of the first joint 33 and the second joint 34 may coincide (completely repeat) with each other.

[0073] As described above, the retainer 20 is a resin component covering the busbar 30 and is mounted on the stator 3. In this embodiment, the retainer 20 has an annular main body 21 and an outer wall portion 22 and an inner wall portion 23 erected from the main body 21 along the second axial direction Da2.

[0074] The main body 21 is a resin component covering each busbar 30, for example, appearing annular (ring-shaped) when viewed from the axial direction, and as... Figure 6As shown, it appears flat when viewed radially. The thickness of the main body 21 in the axial direction is preferably set to be slightly greater than the thickness of each busbar 30 in the axial direction, so as to cover the three busbars 30 from both sides in the axial direction.

[0075] like Figure 5 As shown, the main body 21 may be provided with a first notch 24 that exposes the first joint 33 and a second notch 25 that exposes the second joint 34. In this embodiment, corresponding to the case where three busbars 30 having first joints 33 and second joints 34 are provided, three first notches 24 and three second notches 25 are provided respectively.

[0076] The first notch 24 is recessed radially inward toward the main body 21, forming a space that exposes the first joint 33 toward the first axial direction Da1. Preferably, the first notch 24 only exposes the first joint 33 in the first portion 31 toward the first axial direction Da1. That is, the first notch 24 is configured not to expose the portions of the first portion 31 adjacent to the two circumferential sides of the first joint 33 from the main body 21. The first notch 24 can be as follows: Figure 6 as well as Figure 8 It can be configured to extend axially through the main body 21 as shown, or it can be configured to retain a portion of the main body 21 that is closer to the second axial direction Da2 than the first joint 33. It should be noted that, due to the first notch 24, the first joint 33 is also exposed radially inward.

[0077] The second notch 25 is recessed radially outward toward the main body 21, forming a space that exposes the second joint 34 toward the first axial direction Da1. Preferably, like the first notch 24, the second notch 25 exposes only the second joint 34 in the second portion 32 toward the first axial direction Da1. That is, the second notch 25 is configured not to expose the portions of the second portion 32 adjacent to the two circumferential sides of the second joint 34 from the main body 21. Similar to the first notch 24, the second notch 25 can be... Figure 5 as well as Figure 8 It can be configured to extend axially through the main body 21 as shown, or it can be configured to retain a portion of the main body 21 that is closer to the second axial direction Da2 than the second joint 34. It should be noted that, due to the second notch 25, the second joint 34 also protrudes radially outward.

[0078] like Figure 8As shown, multiple (three in this case) recesses can be provided between the three second notches 25 in the circumferential direction, forming recesses on the end face of the main body 21 on the second axial Da2 side. Similarly, multiple (three in this case) recesses can be provided between the three first notches 24 in the circumferential direction, forming recesses on the end face of the main body 21 on the second axial Da2 side. The first notches 24 and the second notches 25, along with these recesses, can be used for temporary positioning of each segmented core 11n when the core unit 11 is composed of multiple segmented cores 11n.

[0079] The outer wall portion 22 is a portion that rises from the outer periphery of the annular main body portion 21 toward the second axial direction Da2. For example, the outer wall portion 22 can be an arc-shaped portion rising from a position on the main body portion 21 other than the second notch 25. For example, as... Figure 5 As shown, the retainer 20 is placed on the first axial Da1 side of the stator 3 by surrounding the outer peripheral wall 12 of the core unit 11 radially outward through the outer wall portion 22 and abutting against the steps of the insulator 11i and the stator core 11c. In this way, the retainer 20 can be placed directly on the stator core 11c without passing through the insulator 11i, thereby suppressing the axial displacement of the busbar 30 relative to the stator 3 due to the dimensional error of the insulator 11i.

[0080] like Figure 8 As shown, the inner wall portion 23 is a portion that rises from the inner periphery of the annular main body portion 21 toward the second axial direction Da2. The inner wall portion 23 can, for example, be an arc-shaped portion that rises from a position on the main body portion 21 other than the first notch 24. Figure 5 As shown, the inner wall portion 23 can be configured to surround the inner peripheral wall 14 of the core unit 11 radially inward when the first busbar unit 4 is assembled relative to the stator 3. The inner wall portion 23 can be used together with the outer wall portion 22 for temporary positioning of each segmented core 11n when the core unit 11 is composed of multiple segmented cores 11n.

[0081] During the assembly of the first busbar unit 4 relative to the stator 3, the end wires Wf of the two in-phase coil groups 17 are respectively led out radially inward and radially outward before the first busbar unit 4 is placed relative to the stator 3. Specifically, the end wire Wf of the two in-phase coil groups 17 that engages with the first joint 33 is hooked radially inward, and the end wire Wf that engages with the second joint 34 is hooked radially outward. It should be noted that in... Figure 5 The diagram shows the state where the final line Wf is drawn out to the radially inner side and the radially outer side, respectively.

[0082] Then, the first busbar unit 4 is mounted on the stator 3 such that the first joint 33 is adjacent to the end wire Wf hooked radially inward and the second joint 34 is adjacent to the end wire Wf hooked radially outward. In this way, in the area (prescribed angle region Rα) where the first portion 31 and the second portion 32 of the two busbars 30 overlap when viewed radially, the end wires Wf hooked to the first joint 33 and the end wires Wf hooked to the second joint 34 are hooked in different directions, thereby enabling the wiring of these windings W in a manner that avoids tangling or crossing. This suppresses contact between the end wires Wf or simplifies the tangling of the end wires Wf.

[0083] Furthermore, as described above, the portion of the winding W that is led out to the first axial direction Da1 in each coil group 17 is the end wire Wf that becomes a free end, so it is easy to implement the hooking of such winding W.

[0084] After the first busbar unit 4 is mounted relative to the stator 3, the end wire Wf, which is led out radially inward, is folded towards the first axial direction Da1 and radially outward, and hooked into the groove 37 of the adjacent first joint 33, abutting against the first joint 33 from the first axial direction Da1 side. The first joint 33 is exposed towards the first axial direction Da1 due to the first notch 24, thus enabling the wiring of the end wire Wf. The end wire Wf is then joined to the first joint 33 by spot welding, which melts and bonds the end wire Wf and the first joint 33 together by applying pressure from the first axial direction Da1 side.

[0085] After the first busbar unit 4 is mounted relative to the stator 3, the end wire Wf, which is led out radially outward, is folded towards the first axial direction Da1 and radially inward, and hooked into the groove 37 of the adjacent second joint 34, abutting against the second joint 34 from the first axial direction Da1 side. Similar to the first joint 33, the second joint 34 is exposed towards the first axial direction Da1 due to the second notch 25, thus enabling the wiring of the end wire Wf. The end wire Wf is then joined to the second joint 34 by spot welding, which melts and bonds the end wire Wf and the second joint 34 together by applying pressure from the first axial direction Da1 side.

[0086] In this way, each terminal wire Wf is joined to each joint 33, 34 by spot welding rather than by brazing based on manual operation, thereby reducing the labor time involved in the wiring of the terminal wire Wf. During spot welding, each joint 33, 34, which is pressurized towards the second axial direction Da2, is supported by the busbar 30 (excluding the joints 33, 34) covered by the main body 21 of the retainer 20 mounted on the stator 3. This prevents the joints 33, 34 from moving towards the second axial direction Da2 or the busbar 30 from falling off during spot welding. In particular, when each joint 33, 34 is provided in portions other than the first end 35 and the second end 36 as described above, the portions adjacent to both sides of these joints 33, 34 are covered by the main body 21, thus each joint 33, 34 is supported at both ends. This increases the holding force of the busbar 30 during spot welding, further preventing the busbar 30 from falling off.

[0087] [1-5. Second busbar unit]

[0088] The second busbar unit 5 is a component mounted on the second axial Da2 side of the stator 3 and connecting the three-phase coils 16 in a delta connection manner (delta connection method), such as... Figure 9 As shown, it has a resin retainer 40 and a plurality of busbars 50. The second busbar unit 5 is configured as an insert molded article formed by molding a plurality of busbars 50 using the resin retainer 40 and components, or the resin retainer 40.

[0089] Each busbar 50 is a conductive component that connects two different phases of the three-phase coils 16. In this embodiment, the starting lines Ws of two U-phase coil groups 17u, two V-phase coil groups 17v, and two W-phase coil groups 17w are led out from the second axial direction Da2 side of the stator 3. Correspondingly, the second busbar unit 5 is provided with three busbars 50: a U-line busbar 50u, a V-line busbar 50v, and a W-line busbar 50w.

[0090] like Figure 3 As shown, the U-line busbar 50u connects the starting wire Ws of one side of the two U-phase coil groups 17u to the starting wire Ws of one side of the two V-phase coil groups 17v. The V-line busbar 50v connects the starting wire Ws of the other side of the two V-phase coil groups 17v to the starting wire Ws of one side of the two W-phase coil groups 17w. The W-line busbar 50w connects the starting wire Ws of the other side of the two U-phase coil groups 17u to the starting wire Ws of the other side of the two W-phase coil groups 17w.

[0091] like Figure 9As shown, each of the three busbars 50 may have a base plate portion 51 extending circumferentially and covered (embedded in) by a retainer 40. The base plate portion 51 may be, for example, a long strip extending circumferentially. The three base plate portions 51 may be disposed at the same axial position and may not overlap each other when viewed from the axial direction, i.e., disposed on the same plane.

[0092] The starting wire Ws of each coil group 17 is joined to a portion of the substrate 51. Hereinafter, the portion of the substrate 51 of each busbar 50 that joins the starting wire Ws will be referred to as the joining portion 52. Figure 3 As shown, the U-line busbar 50u, V-line busbar 50v, and W-line busbar 50w can be the starting wires Ws of different phase coil groups 17, which are connected to each other from the common slot 15. Correspondingly, each busbar 50 is provided with a joint 52, and the joint 52 of each busbar 50 can be configured to overlap axially with the slot 15 through which the starting wire Ws is led out and connected.

[0093] Corresponding to the case where the starting wire Ws of each coil group 17 is led out from three slots 15 arranged every three in the circumferential direction, as... Figure 9 As shown, the three joints 52 can be arranged circumferentially at equal intervals and separated from each other, overlapping each of the three grooves 15. It should be noted that... Figure 9 The diagram shows the initial line Ws being led out to the second axial direction Da2 side. The three joints 52 can be configured, for example, to be located radially inward of the initial line Ws when the second busbar unit 5 is mounted on the stator 3.

[0094] It should be noted that each busbar 50 may be configured as a terminal that is electrically connected to an external power supply device (not shown). In this case, each busbar 50 may also have a terminal portion 53 that is erected from the end of the substrate portion 51 in the extension direction toward the second axial direction Da2 and connected to the external power supply device.

[0095] As described above, the retainer 40 is a resin component that covers the substrate portion 51 of the busbar 50 and is mounted on the stator 3. The retainer 40 may be provided with a main body portion 41 for covering the substrate portion 51 of each busbar 50. When each busbar 50 is configured as a terminal, the retainer 40 may also be provided with a protrusion 42 for covering the portion of the terminal portion 53 of each busbar 50 on the first axial Da1 side.

[0096] The main body 41 is, for example, annular when viewed axially and flat when viewed radially. In the main body 41, as part of a structure to reduce the time required for assembling the second busbar unit 5 relative to the stator 3 and for wiring the starting wire Ws, through holes 43 and notches 44 may be provided around the joint 52. Three through holes 43 and three notches 44 may be provided corresponding to the presence of three joints 52.

[0097] The through hole 43 is a hole that extends axially and allows the starting line Ws to pass through. Additionally, the notch 44 is a portion of the main body 41 that is cut away from the second axial direction Da2 side, either radially inside or radially outside the through hole 43, to expose the joint portion 52 of the substrate portion 51 towards the second axial direction Da2, thus creating a space. The notch 44 can be provided adjacent to the radially inside side of the through hole 43, corresponding to the case where the joint portion 52 is configured to be located radially inside the starting line Ws.

[0098] The starting wires Ws of the coil groups 17 of different phases connected to each busbar 50 are, for example, drawn from a common slot 15, and as... Figure 9 As shown, the wires pass through the common through-hole 43. The portion of the winding W forming each coil group 17 that is led out to the second axial direction Da2 side is the starting wire Ws, which becomes the fixed end. As mentioned above, the starting wire Ws has the characteristic that the position of the starting wire Ws is not easily deviated for each coil group 17, so the starting wire Ws can be passed through the through-hole 43 simply by placing the second busbar unit 5 on the stator 3. Therefore, there is no need to adjust the position of the starting wire Ws or to lock the starting wire Ws in place, thereby reducing the time involved in assembling the second busbar unit 5 relative to the stator 3. In addition, the starting wire Ws can be led out to the position suitable for joining to the joint 52, that is, through the through-hole 43, with high reproducibility.

[0099] The starting wire Ws, passing through the through hole 43, is bent radially inward and abuts against the joint 52 exposed along the second axis Da2 from the side of the second axis Da2 via a notch 44. The starting wire Ws abutting against the joint 52 is joined to the joint 52 by spot welding, which melts and bonds the joint 52 and the starting wire Ws together by applying pressure from the second axis Da2 side, rather than by brazing based on manual work. Therefore, the time involved in wiring the starting wire Ws can be reduced.

[0100] During spot welding, the joint portion 52, which is pressurized toward the first axial direction Da1, is supported by the base plate portion 51, which is covered by the main body portion 41 of the retainer 40 mounted on the stator 3. This prevents the joint portion 52 from moving toward the first axial direction Da1 or the busbar 50 from falling off during spot welding. In other words, in this embodiment, because the base plate portion 51 is covered by the retainer 40 mounted on the stator 3 and a notch 44 is provided that exposes the joint portion 52 of the base plate portion 51 toward the second axial direction Da2, the joint portion 52 can be joined to the starting line Ws by spot welding rather than by brazing based on manual operation.

[0101] Furthermore, the portion of the winding W in each coil group 17 that engages with the joint 52 is a starting wire Ws that is less prone to deviation in the lead-out position, and these starting wires Ws are always led out from the through hole 43. Therefore, the reproducibility of the position of the starting wires Ws on the side where spot welding is performed can be improved. As a result, when the joining process of the starting wires Ws is automated and incorporated into the manufacturing process of the motor 1, the situation where the handling of the starting wires Ws becomes complicated can be prevented.

[0102] [2. Functions and Effects]

[0103] (1) In the first busbar unit 4 described above, the retainer 20 has an annular region R in a plane P orthogonal to the axis C, centered on the axis C and having a predetermined radial width H. Multiple busbars 30 are respectively disposed within this annular region R. Furthermore, the centers of the arcs of each busbar 30 are staggered, and at least a portion of each busbar 30 overlaps with other busbars 30 within a predetermined angle range of the annular region R. This reduces the axial thickness of the portion of the retainer 20 covered by the multiple busbars 30 (in this embodiment, the main body 21). This allows for space-saving within the motor 1 in the axial direction, thereby suppressing the increase in motor size.

[0104] (2) In the first busbar unit 4 and the motor 1 described above, the three busbars 30, in which the three-phase coils 16 (coil group 17) provided on the stator 3 are wired in the same phase, are covered by the retainer 20 at the same axial position relative to the retainer 20. This reduces the axial thickness of the portion of the retainer 20 where these busbars 30 are covered (in this embodiment, the main body 21). This allows for space-saving within the motor 1 in the axial direction, thereby suppressing the increase in motor size.

[0105] Furthermore, in the first busbar unit 4 and the motor 1 described above, the first portion 31 of each phase busbar 30 is located radially inward of the second portion 32 of the busbar 30, and is configured to overlap with the second portion 32 of the busbar 30 of a different phase when viewed radially. Thus, the first portion 31 and the second portion 32 of each phase busbar 30 can be extended and disposed near the coil 16 (coil group 17) of the corresponding phase, thereby enabling the connection of each end wire Wf (winding wire W) to the busbar 30 of each phase without the need for complex winding of each end wire Wf (winding wire W).

[0106] (3) In the first busbar unit 4 described above, the first joint portion 33 of the busbar 30, which is covered by the retainer 20 mounted on the stator 3, is exposed to the first axial direction Da1 through the first notch 24. Similarly, the second joint portion 34 of the busbar 30, which is covered by the retainer 20 mounted on the stator 3, is exposed to the first axial direction Da1 through the second notch 25. Thus, before the first busbar unit 4 is mounted relative to the stator 3, the end wires Wf, which are respectively hooked to the radially inner side and the radially outer side, can be spot-welded from the first axial direction Da1 side to the first joint portion 33 and the second joint portion 34, respectively. Therefore, assembly can be performed to reduce labor time compared to brazing based on manual work.

[0107] (4) Furthermore, in the first busbar unit 4 described above, only the first joint 33 in the first part 31 is exposed to the first axial direction Da1 through the first notch 24, while the portions adjacent to both sides of the first joint 33 are not exposed and are covered by the retaining member 20. In addition, only the second joint 34 in the second part 32 is exposed to the first axial direction Da1 through the second notch 25, while the portions adjacent to both sides of the second joint 34 are not exposed and are covered by the retaining member 20. Thus, each joint 33, 34 is in a state of being supported at both ends, so that the connection of the end line Wf with each joint 33, 34 can be performed more appropriately.

[0108] (5) If grooves 37 for hooking the end wire Wf are provided on the radially inner side of the first joint 33 and the radially outer side of the second joint 34, the end wire Wf can be positioned relative to each joint 33, 34 before it joins with each joint 33, 34. As a result, the joining of the end wire Wf relative to each joint 33, 34 can be performed more appropriately.

[0109] (6) If the portion of the winding W that is led out to the first axial direction Da1 in each coil group 17 is a free end wire Wf, then it is easy to hook the end wire Wf that is engaged with the first joint 33 radially inward and the end wire Wf that is engaged with the second joint 34 radially outward. In addition, in the area where the first part 31 and the second part 32 of the two busbars 30 overlap when viewed radially, if the end wire Wf engaged with the first joint 33 and the end wire Wf engaged with the second joint 34 are hooked to each other in different radial directions, then these end wires Wf can be wired in a way that does not cause entanglement or crossing. As a result, the winding of the end wires Wf can be simplified, and the situation where the end wires Wf come into contact with each other and are energized can be suppressed.

[0110] (7) If the length L of the overlap between the first part 31 of each busbar 30 and the second part 32 of other busbar 30 in the circumferential direction is set to be approximately the same as the length of the arc of a sector with the angle obtained by dividing 360° by the number of slots 15 of the stator 3 as the central angle, then compared with the case where the overlap length L between the first part 31 and the second part 32 is longer than the length of the arc, it is easier to achieve insulation between the busbars 30 and each other, and it is possible to suppress the complexity of the wiring of the end wire Wf.

[0111] (8) If the three busbars 30 provided in the first busbar unit 4 are all set to the same shape, the components (busbars 30) can be made common. This can help reduce the manufacturing cost of the motor 1.

[0112] [3. Other]

[0113] The structure of the first busbar unit 4 and the motor 1 described above is an example and is not limited to the above structure. For example, the motor 1 can also be configured by arranging the second busbar unit 5, the stator 3, and the first busbar unit 4 in this order from the first axial direction Da1 towards the second axial direction Da2. In this case, the "specified axial direction" described in the technical solution becomes the second axial direction Da2. The first circumferential direction Dc1 and the second circumferential direction Dc2 in the first busbar unit 4 described above are only examples, and these directions can also be specified in reverse.

[0114] The first busbar unit 4 may not be an embedded molded product formed by molding multiple busbars 30 using a resin retainer 20. Instead, it may be a structure formed by assembling (assembling) multiple busbars 30 inside the retainer 20 after the resin retainer 20 is molded. Similarly, the second busbar unit 5 may not be an embedded molded product. Instead, it may be a structure formed by assembling (assembling) multiple busbars 50 inside the retainer 20 after the resin retainer 20 is molded. The terminal wires Wf of the busbars 30 in the first busbar unit 4 may also be joined to the first joint 33 and the second joint 34 by brazing. Similarly, the terminal wires Wf of the busbars 50 in the second busbar unit 5 may also be joined to the joint 52 by brazing.

[0115] The busbar unit located on the second axial Da2 side of the stator 3 may not be the second busbar unit 5 that connects the three-phase coils 16 in a delta connection (delta connection). It may also be a busbar unit that connects the three-phase coils 16 in a star connection. It should be noted that the motor 1 may also not have the second busbar unit 5.

[0116] The winding W does not necessarily have to form two adjacent coils 16 of the same phase; for example, it can form a single coil 16. That is, the number of windings W provided on the stator 3 is not limited to the six mentioned above. The number of coils 16 provided on the stator 3 also does not have to be twelve, as long as it is at least a multiple of six.

[0117] The portion of the winding W forming each coil 16 (coil group 17) that is led out to the first axial direction Da1 side may not be the end wire Wf. That is, the busbar 30 of the first busbar unit 4 may not connect the end wires Wf of each coil 16 (coil group 17). It should be noted that the end wires Wf of the winding W of coils 16 that are adjacent in the circumferential direction to different phases may not be led out from the same slot 15.

[0118] The first notch 24 and the second notch 25 provided in the retainer 20 of the first busbar unit 4 can also be omitted. For example, if the first end 35 of each busbar 30 is positioned radially inward (protruding radially inward from the retainer 20) and functions as a first joint 33, the first notch 24 can be omitted. Similarly, if the second end 36 of each busbar 30 is positioned radially outward (protruding radially outward from the retainer 20) and functions as a second joint 34, the second notch 25 can be omitted.

[0119] Furthermore, in the above embodiment, the portions adjacent to both sides of the first joint 33 and the second joint 34 are not exposed and are covered by the retainer 20 of the first busbar unit 4, but a portion of these adjacent portions may also be exposed from the retainer 20. The grooves 37 provided in each joint 33, 34 may also be omitted. The outer wall portion 22 and the inner wall portion 23 of the retainer 20 of the first busbar unit 4 may also be omitted. In this case, the main body portion 21 of the retainer 20 can be directly mounted on the first axial Da1 side of the stator 3.

[0120] The retainer 20 described in technical solution 1 only needs to be an annular shape that surrounds at least its axis and can cover multiple busbars 30; it does not necessarily have to be annular. The retainer 20 can be, for example, a polygon, an ellipse, or other non-circular shape, and the main body 21 of the retainer 20 may not appear plate-like when viewed radially. The busbars 30 described in technical solution 1 only need to be arc-shaped with their centers offset from each other; they do not necessarily have to be arc-shaped. For example, if the retainer 20 is elliptical, the busbar 30 can also be an elliptical arc-shaped component disposed within the annular region of the ellipse.

[0121] The retainer 20 described in technical solution 3 only needs to be shaped to cover at least a plurality of busbars 30, and it does not have to be annular. The retainer 20 can be, for example, disc-shaped, fan-shaped, or rectangular, and the main body 211 of the retainer 20 may not be plate-shaped when viewed radially. The busbar 30 described in technical solution 3 only needs to be provided to extend at least circumferentially, with the first portion 31 of each busbar 30 located radially inward than the second portion, and it does not have to be an arc-shaped structure eccentric to axis C. The busbar 30 may, for example, be a vortex-shaped structure extending radially outward from the first circumference towards Dc1 to the second circumference towards Dc2.

[0122] The number of busbars provided in a busbar unit is not limited to three. In addition, the multiple busbars provided in a busbar unit do not all have to be the same shape.

[0123] Explanation of reference numerals in the attached figures

[0124] 1. Motor (brushless motor)

[0125] 1s axis

[0126] 2 rotors

[0127] 3. Stator

[0128] 4 First busbar unit (busbar unit)

[0129] 15 slots

[0130] 16 coils

[0131] 16u U-phase coil (coil)

[0132] 16V V-phase coil (coil)

[0133] 16W phase coil (coil)

[0134] 17. Coil Group (Coil)

[0135] 17u U-phase coil group (coil)

[0136] 17V V-phase coil assembly (coil)

[0137] 17W W-phase coil assembly (coil)

[0138] 20 Retaining parts

[0139] 24 First Gap

[0140] 25 Second Gap

[0141] 30 busbars

[0142] 30u U-phase busbar (busbar)

[0143] 30V V-phase busbar (busbar)

[0144] 30W phase busbar (busbar)

[0145] 31 Part One

[0146] 32 Part Two

[0147] 33 First joint

[0148] 34 Second joint

[0149] 37 slots

[0150] α is the specified angle.

[0151] C-axis

[0152] Cu-U phase flow line center (center of the arc)

[0153] Cv V phase flow line center (arc center)

[0154] Cw W phase confluence center (arc center)

[0155] Da1 First Axis (Specified Axis)

[0156] H specifies the radial width

[0157] L Overlap length (the length by which the first part of the busbar overlaps with the second part of any other busbar in the circumferential direction)

[0158] P plane

[0159] R-shaped region

[0160] W winding

[0161] Wf (End Line)

Claims

1. A busbar unit, characterized in that, The bus bar unit includes: Multiple arc-shaped busbars; and A retainer covering multiple of the aforementioned busbars and arranged in a ring around the axis. The retainer has an annular region with a specified radial width centered on the axis in a plane orthogonal to the axis. Each of the aforementioned busbars is disposed within the annular region, and the centers of the arcs are staggered from each other. The circumferential portions of each of the busbars are respectively configured to overlap radially with other busbars within a specified angular range centered on the axis in the annular region.

2. The busbar unit according to claim 1, characterized in that, All of the aforementioned busbars are of the same shape.

3. A busbar unit, which is an inner rotor type busbar unit of a brushless motor having an annular stator and a rotor located on the inner side of the radial direction of the stator, characterized in that, The bus bar unit includes: A resin retainer, which is mounted axially on a predetermined axial side of the stator; and Multiple conductive busbars connect the coils of the three phases of the stator in phase. Each of the busbars extends circumferentially along the stator and is covered by the retainer at the same position in the axial direction relative to the retainer, with a first portion on one end side in the circumferential direction located on the inner side than a second portion on the other end side in the circumferential direction. Each of the busbars has: A first joint is provided in the first part and is engaged with the winding of one of the two coils that form the connection of the busbar; as well as A second joint, disposed in the second portion, engages with the winding that forms the other of the two coils. The first portion of each of the busbars overlaps with the second portion of any other busbar when viewed from the radial direction. The retainer has a first notch recessed from the inner side in the radial direction, exposing the first joint portion to the predetermined axis, and a second notch recessed from the outer side in the radial direction, exposing the second joint portion to the predetermined axis.

4. The busbar unit according to claim 3, characterized in that, The first joint and the second joint are respectively joined with the end wires of the windings of the two coils.

5. The busbar unit according to claim 3, characterized in that, The portions of the first part adjacent to the two sides of the first joint in the circumferential direction and the portions of the second part adjacent to the two sides of the second joint in the circumferential direction are both covered by the retaining member.

6. The busbar unit according to claim 3, characterized in that, Grooves for securing the winding are provided on the inner side of the first joint and on the outer side of the second joint in the radial direction.

7. The busbar unit according to claim 3, characterized in that, The length by which the first portion of each of the busbars overlaps with the second portion of any other busbar in the circumferential direction is the same as the length of an arc having a sector with a central angle obtained by dividing 360° by the number of slots in the stator.

8. The busbar unit according to claim 3, characterized in that, All of the aforementioned busbars are of the same shape.

9. A brushless motor, characterized in that, The brushless motor has the following features: The busbar unit as described in claim 3; The stator on which the busbar unit is disposed; and The rotor that rotates integrally with the shaft on the inner side of the stator.

10. A brushless motor, characterized in that, The brushless motor has the following features: The busbar unit as described in claim 1; An annular stator on which the busbar unit is disposed; and The rotor is located on the inner side of the stator in the radial direction and rotates integrally with the shaft on the inner side of the stator.

Images