Busbar unit and brushless motor

Abstract

A busbar unit (4) is provided with: a busbar (50) having a substantially arc-shaped substrate portion (51); and a non-conductive holder (40) covering the substrate portion (51). The holder (40) includes: an exposure portion (44) that exposes a portion (52) of the substrate portion (51); and a guide portion (43) that guides bending of a conductive wire (Ws) connected to the portion (52) toward the exposure portion (44). Alternatively, the busbar unit (4) may also be provided with: the busbar (50) having the plate-shaped substrate portion (51); and a resin holder (40) covering the substrate portion (51). The holder (40) may include: the exposure portion (44) that exposes only the portion (52) of the substrate portion (51) in a first direction (Da2); and the guide portion (43) that guides the conductive wire (Ws) joined to the portion (52) from a second direction (Da1) to the first direction (Da2).

Description

Bus bar unit and brushless motor

[0001] This case relates to a bus bar unit and a brushless motor including the bus bar unit.

[0002] Conventionally, in a motor, a conducting wire forming a coil built therein is known to be joined to a conductive bus bar by soldering (for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2024-123482

[0004] By the way, in a motor having a stator as disclosed in Patent Document 1, soldering for joining a conducting wire to a bus bar may be performed manually, so there is room for improvement in that the man-hours related to the joining increase. Note that the above problems are problems that can occur when joining a conducting wire to a bus bar, and are not limited to the case where this conducting wire is the conducting wire (winding) of a coil, and also not limited to the case where the device provided with the bus bar is a motor or a stator.

[0005] This case was devised in view of such problems, and one of the purposes is to provide a bus bar unit and a brushless motor that can reduce the man-hours related to joining a conducting wire to a bus bar. Note that not limited to this purpose, another purpose of this case is to achieve an effect that cannot be obtained by the conventional technology, which is an effect derived from each configuration shown in the mode for carrying out the invention described later.

[0006] The disclosed bus bar unit and brushless motor can be realized as the following disclosed modes (application examples) and solve at least some of the above problems. Note that Mode 3 is a mode that can be additionally and appropriately selected for other bus bar units of Mode 2 and is an omissible mode. That is, Mode 3 does not disclose an essential mode or configuration for other bus bar units of this case.

[0007] Mode 1. The disclosed bus bar unit includes a bus bar having a substantially arc-shaped substrate portion, and a non-conductive holder covering the substrate portion. The holder has an exposed portion that exposes a part of the substrate portion, and a guide portion that guides bending of a conducting wire connected to the part to the exposed portion.

[0008] Embodiment 2. Another busbar unit of the Disclosure comprises a conductive busbar having a plate-shaped substrate portion, and a resin holder covering the substrate portion. The holder has an exposed portion that exposes only a portion of the substrate portion in a first direction in the thickness direction of the substrate portion, and a guide portion attached to the exposed portion that guides a conductor joined to the portion toward the first direction from a second direction opposite to the first direction.

[0009] Embodiment 3. In an embodiment including Embodiment 2 described above, the busbar unit is applied to an inner rotor type brushless motor comprising an annular stator and a rotor located radially inward of the stator, wherein the conductor is the starting wire of the winding forming the coil of the stator and is preferably drawn out in a predetermined axial direction of the stator. Furthermore, in the busbar unit, with the first direction aligned along the predetermined axial direction, the holder is mounted on the predetermined axial side of the stator, the guide portion is a through hole that penetrates in the axial direction and through which the starting wire is inserted, and the exposed portion is preferably a notch that exposes a part of the substrate portion in the predetermined axial direction on the inner side of the through hole or on the radially outward side.

[0010] Embodiment 4. The disclosed brushless motor comprises a busbar unit including Embodiment 3 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.

[0011] According to the disclosed busbar unit and brushless motor, the man-hours required for connecting wires to the busbar can be reduced.

[0012] Figure 1 is an exploded perspective view of a brushless motor to which the busbar unit according to the embodiment is applied. Figure 2 is a schematic diagram showing the wiring method and connection method of the windings forming the coils provided on the stator. Figure 3 is a perspective view for explaining the characteristics of the start and end wires of the windings, showing a part of the core unit of the stator and the windings wound around that part. Figure 4 is a perspective view of the first busbar unit and stator of the brushless motor of Figure 1, viewed from the first axis direction. Figure 5 is a perspective view of the first busbar unit, viewed from the second axis direction. Figure 5 is a perspective view of the second busbar unit and stator of the brushless motor of Figure 1, viewed from the second axis direction. Figure 7 is a cross-sectional view of the second busbar unit taken along the line X-X.

[0013] The busbar unit and brushless motor as embodiments will be described with reference to the drawings. The embodiments shown below are merely illustrative, and there is no intention to exclude various modifications and applications of technologies not explicitly shown in the embodiments below. Each component of these embodiments can be modified in various ways without departing from their spirit.

[0014] The busbar unit comprises a busbar having a substantially arc-shaped substrate portion and a non-conductive holder covering the substrate portion. The holder is provided with an exposed portion that exposes a part of the substrate portion and a guide portion that guides the bending of the conductor to be joined to this portion toward the exposed portion.

[0015] Alternatively, the busbar unit comprises a conductive busbar having a plate-shaped substrate portion and a resin holder covering this substrate portion. The holder is provided with an exposed portion that exposes only a part of the substrate portion in one direction (first direction) in the thickness direction of the substrate portion, and a guide portion that guides a conductor to be joined to this exposed portion. The guide portion is attached to the exposed portion and guides the conductor from a second direction (the other direction in the thickness direction) opposite to the first direction toward the first direction.

[0016] With the above configuration, the guide wires can be brought into contact with a part of the circuit board and joined to the busbar by spot welding, contributing to a reduction in man-hours. The busbar unit described in detail below is applied to a brushless motor as an example, but the application of the above busbar unit is not limited to motors, but may also be various electrical components such as distribution boards, storage batteries, and generators.

[0017] [1. Configuration] [1-1. Overall Configuration] Figure 1 is an exploded perspective view of a brushless motor 1 (hereinafter also referred to as "motor 1") to which the busbar unit according to this embodiment is applied. The brushless motor 1 according to this embodiment is an inner rotor type brushless motor and, as shown in Figure 1, comprises a rotor 2 that rotates integrally with the shaft 1s, a stator 3, and busbar units 4 and 5. The motor 1 is constructed by housing the rotor 2, stator 3, and busbar units 4 and 5 in a bottomed cylindrical housing 6. An end bell 7 as a lid member may be attached to the opening side (left side in the figure) of the housing 6.

[0018] Hereinafter, the direction in which the shaft 1s extends (the direction of the axis C of the shaft 1s) is referred to as the axial direction. Of the axial directions, the direction in which the bottom of the housing 6 is located relative to the opening of the housing 6 (right side in Figure 1) is referred to as the first axial direction Da1, and the direction opposite to the first axial direction Da1 is referred to as the second axial direction Da2 (predetermined axial direction). The direction perpendicular to the axial direction, both the direction away from the axis C and the direction toward the axis C, is referred to as the radial direction. Of the radial directions, the direction away from the axis C is referred to as the radially outward (outward), and the direction toward the axis C is referred to as the radially inward (inward). The direction perpendicular to the axial direction, that revolves around the axis C, is referred to as the circumferential direction. Of the circumferential directions, the clockwise direction viewed from the first axial direction Da1 side is referred to as the first circumferential direction Dc1, and the direction opposite to the first circumferential direction Dc1 (counterclockwise) is referred to as the second circumferential direction Dc2.

[0019] The motor 1 illustrated here, as shown in Figure 1, comprises two busbar units 4 and 5 arranged to sandwich the stator 3 in the axial direction. 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, stator 3, and second busbar unit 5 are arranged in this order from the first axial direction Da1 to the second axial direction Da2 and housed in the housing 6. The rotor 2 and shaft 1s are inserted radially inside the stator 3 and the two busbar units 4 and 5. In this embodiment, the busbar unit is provided (applied) as the second busbar unit 5.

[0020] [1-2. Rotor] The rotor 2 comprises, for example, a rotor core that rotates integrally with the shaft 1s and a plurality of 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, for example, two bearings 8 that sandwich the rotor core in the axial direction between the bottom of the housing 6 and the end bell 7.

[0021] [1-3. Stator] The stator 3 is an annular component with a space on its radially inward side where the rotor 2 is positioned, and is concentric with axis C. Therefore, the axial, radial, and circumferential directions of axis C described above can also be expressed as the axial, radial, and circumferential directions of the stator 3. In this embodiment, the stator 3 has an annular (cylindrical) external shape, but the shape of the stator 3 is not limited to this.

[0022] As shown in Figure 2, the stator 3 comprises a substantially cylindrical core unit 11 and a plurality of coils 16. The core unit 11 is provided, for example, as an insert molded product in which the stator core is molded with resin that serves as an insulator, and is fixed inside the housing 6. The core unit 11 has a cylindrical outer peripheral wall 12, a plurality of teeth 13 projecting radially inward from the inner peripheral surface of the outer peripheral wall 12, and an arc-shaped inner peripheral wall 14 extending circumferentially on the radially inward side of each tooth 13. The plurality of teeth 13 are provided at equal intervals, spaced apart from each other in the circumferential direction. The same number of slots 15 as the number of teeth 13 are formed between the plurality of teeth 13. The coils 16 are formed by winding a wire W around each of the plurality of teeth 13, and the same number of coils as the number of teeth 13 are provided.

[0023] As shown in Figures 2 and 3, the stator 3 of this embodiment is provided with twelve teeth 13, twelve slots 15, and twelve coils 16. The stator 3 is provided with four U-phase coils 16u, four V-phase coils 16v, and four W-phase coils 16w as the twelve coils 16. The U-phase coil 16u is supplied with U-phase current, the V-phase coil 16v is supplied with V-phase current, and the W-phase coil 16w is supplied with W-phase current.

[0024] In Figure 2, only two teeth 13 that are adjacent in the circumferential direction out of the twelve teeth 13 are shown with dashed lines. Also, out of the twelve slots 15, only one slot 15 formed between the two shown teeth 13 is labeled with a reference numeral. In Figure 3, only parts of the twelve teeth 13 and twelve slots 15 are labeled with reference numerals.

[0025] As shown in Figure 2, for example, the stator 3 has two sets of U-phase coils 16u, V-phase coils 16v, and W-phase coils 16w arranged side by side in the circumferential direction. That is, two of the four U-phase coils 16u are provided adjacent to each other in the circumferential direction, and two V-phase coils 16v are provided adjacent to each other in the circumferential direction, adjacent to the second circumferential direction Dc2 side of the two U-phase coils 16u. Also, two W-phase coils 16w are provided adjacent to each other in the circumferential direction, adjacent to the second circumferential direction Dc2 side of the two V-phase coils 16v, and the remaining two U-phase coils 16u are provided adjacent to each other in the circumferential direction, adjacent to the second circumferential direction Dc2 side of the two W-phase coils 16w. The remaining two V-phase coils 16v are provided adjacent to each other in the circumferential direction, adjacent to the second circumferential direction Dc2 side of the remaining two U-phase coils 16u, and further, the remaining two W-phase coils 16w are provided adjacent to each other in the circumferential direction, adjacent to these second circumferential direction Dc2 side.

[0026] Hereinafter, two adjacent coils 16 of the same phase will be collectively referred to as a coil group 17. The stator 3, which has twelve coils 16, can also be described as having two U-phase coil groups 17u, two V-phase coil groups 17v, and two W-phase coil groups 17w. Furthermore, regarding the arrangement of the coils 16 described above, the stator 3 will be provided with the U-phase coil group 17u, the V-phase coil group 17v, and the W-phase coil group 17w arranged in this order in the circumferential direction, and the two coil groups 17 of each phase will be provided so as to face each other across the axis C.

[0027] In this embodiment, as shown in Figure 3, each coil group 17 is formed by a single continuous winding W. That is, the stator 3 is provided with six windings W, and each coil group 17 is formed by winding each winding W around two teeth 13 adjacent to each other in the circumferential direction. More specifically, the winding W forming each coil group 17 is wound around one of two teeth 13 adjacent to each other in the circumferential direction, and then wound around the other tooth 13 without being cut. The windings W forming each coil group 17 may be routed (wired) such that the winding direction around one tooth 13 is opposite to the winding direction around the other tooth 13, as shown in the figure.

[0028] One of the starting wires Ws and ending wires Wf of each winding W is drawn out towards the first axial direction Da1, and the other is drawn out towards the second axial direction Da2. In this embodiment, as shown in Figure 3, all six starting wires Ws of the six windings W are drawn out towards the second axial direction Da2, and all six ending wires Wf of the six windings W are drawn out towards the first axial direction Da1. The six starting wires Ws drawn out towards the second axial direction Da2 are joined (connected) to the bus bar 50 of the second bus bar unit 5, which will be described later, and the six ending wires Wf drawn out towards the first axial direction Da1 are joined (connected) to the bus bar 30 of the first bus bar unit 4, which will be described later.

[0029] Of the six initial wires Ws drawn out in the second axial direction Da2, the initial wires Ws of windings W forming adjacent coil groups 17 may be drawn from the same (common) slot 15. In this embodiment, two initial wires Ws are drawn from each of the three slots 15 located every three in the circumferential direction. Similarly, of the six ending wires Wf drawn out in the first axial direction Da1, the ending wires Wf of windings W forming adjacent coil groups 17 may be drawn from the same slot 15. In this embodiment, two ending wires Wf are drawn from each of the three slots 15 located every three in the circumferential direction. The initial wires Ws and ending wires Wf of each winding W may be drawn from different slots 15, or they may be drawn from the same slot 15, as shown in Figure 3.

[0030] In this context, the starting wire Ws refers to the portion of the winding W (conductor) forming each coil group 17 where the winding begins, and the ending wire Wf refers to the portion of the winding W (conductor) forming each coil group 17 where the winding ends. The electricity supplied to each coil group 17 can flow from the starting wire Ws to the ending wire Wf, or from the ending wire Wf to the starting wire Ws. Therefore, the starting wire Ws and the ending wire Wf are defined independently of the direction of the flow of electricity supplied to each coil group 17.

[0031] Figure 4 is a perspective view showing a part of a core unit 11 and the winding W wound around that part, as an example to illustrate the characteristics of the start wire Ws and end wire Wf of the winding W. In Figure 4, as a part of the core unit 11, the core unit 11 is divided into twelve sections in the circumferential direction, and only one of the twelve divided cores 11n is shown as an example. The core unit 11 may be composed of multiple divided cores 11n that are divided at equal intervals in the circumferential direction in this manner.

[0032] Furthermore, as described above, in the stator 3 of this embodiment, a single winding W is wound continuously around two adjacent teeth 13 to form a single coil group 17 consisting of two coils 16 of the same phase. However, Figure 4 illustrates a case where a single winding W is wound around only one divided core 11n (one tooth) to form a single coil 16. Thus, the stator 3 may be provided with the same number of windings W as the number of teeth 13.

[0033] As shown in Figure 4, the initial wire Ws of the winding W is constrained and fixed by the connecting wire Wc that connects the initial wire Ws and the final wire Wf, which is wound around the teeth. Since the initial wire Ws of the winding W forming each coil group 17 is fixed in this way, the radial position of the initial wire Ws is less likely to vary (less play) for each coil group 17. On the other hand, the final wire Wf, which is the end of the winding of the winding W, is not constrained by the connecting wire Wc, and therefore has the characteristic of being able to be drawn out toward the first axial direction Da1 and radially inward, or toward the first axial direction Da1 and radially outward. From these characteristics, the initial wire Ws can also be described as the fixed end of the winding W, and the final wire Wf can also be described as the free end of the winding W.

[0034] [1-4. First Busbar Unit] The first busbar unit 4 is mounted on the first axial direction Da1 side of the stator 3 and is a component that connects the three-phase coils 16 to each phase. As shown in Figure 5, it has a resin holder 20 and a plurality of busbars 30. Each busbar 30 is a conductive member that connects the three-phase coils 16 to each phase, and extends along the circumferential direction and is covered (embedded) in the holder 20. That is, the first busbar unit 4 is provided as an assembly of a plurality of busbars 30 with the resin holder 20, or as an insert molded product molded by the resin holder 20. In this embodiment, "extended along" is not limited to extending in a direction that coincides with (is parallel to) a reference direction (e.g., the circumferential direction), but also includes extending in a direction that is inclined with respect to the reference direction.

[0035] In this embodiment, the terminal wires Wf of the two U-phase coil groups 17u, the terminal wires Wf of the two V-phase coil groups 17v, and the terminal wires Wf of the two W-phase coil groups 17w are drawn out toward the first axial direction Da1. For this reason, as shown in Figures 3 and 5, the first busbar unit 4 is provided with three busbars 30: a U-phase busbar 30u that connects the terminal wires Wf of the two U-phase coil groups 17u, a V-phase busbar 30v that connects the terminal wires Wf of the two V-phase coil groups 17v, and a W-phase busbar 30w that connects the terminal wires Wf of the two W-phase coil groups 17w.

[0036] The three busbars 30 are provided on the same axial position relative to the holder 20, i.e., on the same plane, without overlapping with each other when viewed from the axial direction, as shown in Figure 5. The three busbars 30 may all have the same shape. Each busbar 30 may be provided such that the first portion 31 on the first circumferential direction Dc1 side is located radially inward from the second portion 32 on the second circumferential direction Dc2 side. The three busbars 30 may be provided, for example, in the shape of a long plate extending spirally in the circumferential direction, and be provided so as to be rotationally symmetric three times around the axis C. Each of the first portion 31 and second portion 32 of each busbar 30 is provided such as shown in Figure 3 that they overlap axially with the slots 15 from which the end wires Wf of the two coil groups 17 of the phase connected by the busbar 30 are drawn, and are joined to each of these end wires Wf.

[0037] The first portion 31 of each busbar 30 and the second portion 32 of any other busbar 30 may be arranged to overlap each other when viewed radially, as shown in Figure 5. In other words, the first portion 31 of each busbar 30 (for example, a U-phase busbar 30u) may be arranged to overlap, when viewed radially, with the second portion 32 of another busbar 30 (for example, a V-phase busbar 30v) that connects a coil group 17 of a different phase (for example, a V-phase coil group 17v) from the coil group 17 of the phase to which the busbar 30 connects (for example, a U-phase coil group 17u).

[0038] The end wires Wf of each of the different phase coil groups 17 drawn from the same slot 15 (for example, the end wire Wf of the U-phase coil group 17u and the end wire Wf of the V-phase coil group 17v) are each drawn out radially inward and radially outward (hooked) before the first busbar unit 4 is placed on the stator 3. As described above, the portions of the windings W that form each coil group 17 that are drawn out toward the first axial direction Da1 are all end wires Wf that become free ends, so hooking of such windings W can be easily performed. Figure 5 illustrates the state in which the end wires Wf are drawn out radially inward and radially outward.

[0039] After the first busbar unit 4 is placed on the stator 3, the end wires Wf drawn radially inward from the same slot 15 (for example, the end wires Wf of the U-phase coil group 17u) are folded in the first axial direction Da1 and radially outward. Subsequently, these end wires Wf (for example, the end wires Wf of the U-phase coil group 17u) are joined to the first portion 31 of a busbar 30 (for example, a U-phase busbar 30u) provided such that the slot 15 from which the end wires Wf are drawn overlaps with the first portion 31, by spot welding or soldering from the first axial direction Da1 side.

[0040] Conversely, among the terminal wires Wf drawn from the same slot 15, the terminal wires Wf drawn radially outward (for example, the terminal wires Wf of the V-phase coil group 17v) are folded inward in the first axial direction Da1 and radially after the first busbar unit 4 is placed on the stator 3. Subsequently, these terminal wires Wf are joined to the second portion 32 of a busbar 30 (for example, a V-phase busbar 30v) provided such that the slot 15 from which the terminal wires Wf are drawn overlaps with the second portion 32, by spot welding or soldering from the first axial direction Da1 side.

[0041] This allows the terminal wires Wf of different phases drawn from the common slot 15 to be connected to the busbar 30 without crossing each other. Thus, contact (energy flow) between the terminal wires Wf is prevented, and the connection process of the terminal wires Wf to the busbar 30 can be easily carried out.

[0042] As described above, the holder 20 is a resin member that covers the busbars 30 and is mounted on the stator 3. In this embodiment, the holder 20 is annular in shape. The holder 20 has a main body portion 21 that is annular (donut-shaped) when viewed from the axial direction and flat when viewed from the radial direction. The three busbars 30 are covered by the main body portion 21. As shown in Figure 5, the main body portion 21 may have three notches on the radially inward side that expose a portion of the first portion 31 of the three busbars 30. In addition, three notches may be provided on the radially outward side that expose a portion of the second portion 32 of the three busbars 30.

[0043] As shown in Figure 6, the holder 20 may further be provided with an outer wall portion 22 erected from the outer peripheral edge of the main body portion 21 toward the second axial direction Da2, and an inner wall portion 23 erected from the inner peripheral edge of the main body portion 21 toward the second axial direction Da2. Multiple grooves may be recessed in the end face of the main body portion 21 on the side toward the second axial direction Da2. These grooves, as well as the outer wall portion 22 and the inner wall portion 23, can be used for the temporary positioning of each segmented core 11n when the core unit 11 is composed of multiple segmented cores 11n.

[0044] [1-5. Second Busbar Unit] The second busbar unit 5 is a component that connects the three-phase coils 16 in a delta connection method (triangle connection method). As shown in FIG. 7, it has a holder 40 and a busbar 50. The holder 40 is a non-conductive member, for example, made of resin. The busbar 50 is a conductive member having a substrate portion 51 that is plate-shaped when viewed from the radial direction and substantially arc-shaped when viewed from the axial direction, and the substrate portion 51 is coated (embedded) in the holder 40. That is, the second busbar unit 5 is provided with the busbar 50 assembled with the resin-made holder 40 or as an insert molded product molded by the resin-made holder 40.

[0045] The second busbar unit 5 is placed on the second axial direction Da2 side of the stator 3 with the holder 40 in a state where one side (first direction) in the plate thickness direction of the substrate portion 51 is along the second axial direction Da2. The second busbar unit 5 of the present embodiment is placed on the second axial direction Da2 side of the stator 3 in a state where the first direction in the plate thickness direction of the substrate portion 51 coincides with the second axial direction Da2. That is, in the present embodiment, the second axial direction Da2 corresponds to the "first direction" described in the claims, and the first axial direction Da1 corresponds to the "second direction" described in the claims.

[0046] In the present embodiment, a plurality of busbars 50 are provided to connect different two-phase coils 16 among the three-phase coils 16. On the second axial direction Da2 side of the stator 3 of the present embodiment, the start lines Ws of the two U-phase coil groups 17u, the start lines Ws of the two V-phase coil groups 17v, and the start lines Ws of the two W-phase coil groups 17w are drawn out. Correspondingly, three busbars 50, namely, the U-line busbar 50u, the V-line busbar 50v, and the W-line busbar 50w, are provided in the second busbar unit 5.

[0047] As shown in FIG. 3, the U-line busbar 50u connects one start line Ws of the two U-phase coil groups 17u and one start line Ws of the two V-phase coil groups 17v. The V-line busbar 50v connects the other start line Ws of the two V-phase coil groups 17v and one start line Ws of the two W-phase coil groups 17w. The W-line busbar 50w connects the other start line Ws of the two U-phase coil groups 17u and the other start line Ws of the two W-phase coil groups 17w.

[0048] Also, in the present embodiment, each bus bar 50 is provided as a terminal electrically connected to an external power supply device (not shown). Therefore, each bus bar 50 further has a terminal portion 53 connected to the external power supply device.

[0049] The substrate portion 51 is, for example, substantially arc-shaped extending along the circumferential direction (i.e., the direction orthogonal to the plate thickness direction). As shown in FIG. 8, the three substrate portions 51 are provided at the same axial position and are arranged so as not to overlap each other when viewed from the axial direction, that is, they are provided on the same plane.

[0050] The start wire Ws of each coil group 17 is joined to a part of the substrate portion 51. Hereinafter, among the substrate portions 51 of each bus bar 50, the portion to which the start wire Ws is joined is referred to as a joining portion 52. Each of the U-phase wire bus bar 50u, V-phase wire bus bar 50v, and W-phase wire bus bar 50w may connect the start wires Ws drawn from the same common slot 15 and being the start wires Ws of coil groups 17 of different phases, as shown in FIG. 3. Correspondingly, the joining portion 52 of each bus bar 50 may be provided so as to axially overlap the slot 15 from which the start wire Ws connected by the bus bar 50 is drawn.

[0051] In the present embodiment, the start wire Ws of each coil group 17 is drawn from three slots 15 located at every other position in the circumferential direction as described above. Therefore, each bus bar 50 is provided with one joining portion 52, and each of the three joining portions 52 is provided at equal intervals and spaced apart from each other in the circumferential direction so as to overlap each of these three slots 15, as shown in FIG. 7. The three joining portions 52 are arranged, for example, to be located radially inside the start wire Ws in a state where the second bus bar unit 5 is placed on the stator 3. The radial positions of the three joining portions 52 are set to be substantially the same position. Note that FIG. 7 shows a state where the start wire Ws is drawn to the second axial direction Da2 side.

[0052] The terminal portion 53 is, for example, a flat plate that is erected from the end of the substrate portion 51 in the extending direction toward the second axial direction Da2. The three terminal portions 53 may be arranged clustered together at one location in the circumferential direction and spaced apart from each other, as shown in Figure 7. In this embodiment, the three terminal portions 53 are clustered between the joint portion 52 of the U-line busbar 50u and the joint portion 52 of the V-line busbar 50v.

[0053] The base plate portion 51 of the U-line busbar 50u, whose joint portion 52 is located on the second circumferential direction Dc2 side of the point where the three terminal portions 53 meet, extends to coincide with the circumferential direction, and a terminal portion 53 is connected to its end on the first circumferential direction Dc1 side. Similarly, the base plate portion 51 of the V-line busbar 50v, whose joint portion 52 is located on the first circumferential direction Dc1 side of the point where the three terminal portions 53 meet, extends to coincide with the circumferential direction, and a terminal portion 53 is connected to its end on the second circumferential direction Dc2 side.

[0054] On the other hand, the base plate portion 51 of the W-line busbar 50w, whose joint portion 52 is located relatively far from the meeting point of the three terminal portions 53, extends in line with the circumferential direction near the joint portion 52, but extends radially outward as it moves toward the first circumferential direction Dc1 (moving away from the joint portion 52 and approaching the terminal portion 53). The base plate portion 51 of the W-line busbar 50w is positioned radially outward from the base plate portion 51 of the U-line busbar 50u so as not to interfere with the base plate portion 51 of the U-line busbar 50u on its first circumferential direction Dc1 side. Specifically, the base plate portion 51 of the W-line busbar 50w is arranged radially parallel to the base plate portion 51 of the U-line busbar 50u, with the start wire Ws connected to the U-line busbar 50u in between. Terminal portions 53 are connected to the end of the base plate portion 51 of the W-line busbar 50w on the first circumferential direction Dc1 side.

[0055] By arranging the substrate portions 51 of the U-line busbar 50u, V-line busbar 50v, and W-line busbar 50w as described above, it becomes possible to arrange these substrate portions 51 in the same axial position, or in other words, on the same plane, without overlapping them in the axial direction.

[0056] As described above, the holder 40 is a resin component that covers the base portion 51 of the busbar 50 and is mounted on the stator 3. The holder 40 in this embodiment has a main body portion 41 and a protrusion portion 42.

[0057] The main body portion 41 is a part for covering the base portion 51 of each bus bar 50, and for example, it has an annular (donut shape) when viewed from the axial direction and a flat plate shape when viewed from the radial direction. The main body portion 41 is provided with an exposed portion 44 that exposes only the joint portion 52 of the base portion 51, and a guide portion 43 that guides the initial wire Ws to be joined to the joint portion 52, as part of a configuration that reduces the number of steps required for assembling the second bus bar unit 5 to the stator 3 and joining the initial wires Ws (conductors) to the bus bars 50.

[0058] In this embodiment, the guide portion 43 is provided as a through-hole that penetrates the main body portion 41 in the axial direction, as shown in Figure 8. Hereinafter, the guide portion 43 will also be referred to as the through-hole 43. When the second busbar unit 5 is placed on the stator 3, the initial wire Ws is inserted through the through-hole 43 from the first axial direction Da1 to the second axial direction Da2. Therefore, the guide portion 43 can also be said to be a part that guides the initial wire Ws from the first axial direction Da1 to the second axial direction Da2.

[0059] The through-holes 43 are provided at positions that coincide with the starting wire Ws in the axial direction, in other words, at positions that coincide with the slots 15 from which the starting wire Ws is drawn. In this embodiment, since the starting wire Ws is drawn from three locations in the circumferential direction (three slots 15 located three apart in the circumferential direction), three through-holes 43 are provided. As described above, the joints 52 of each busbar 50 are provided at positions that coincide in the axial direction with the common slots 15 from which the starting wire Ws connected to the busbar 50 is drawn. For this reason, it can also be said that each of the three through-holes 43 is provided at the same circumferential position as each of the joints 52 of the three busbars 50.

[0060] The initial wires Ws of the different phase coil groups 17 connected by each busbar 50 are drawn out from a common slot 15 and, as shown in Figure 7, inserted through a common through hole 43 and joined to the joint 52 of the busbar 50. In other words, by drawing out the initial wires Ws of the different phase coil groups 17 connected by each busbar 50 from the common slot 15 so that they are adjacent in the circumferential direction, it becomes possible to draw out two initial wires Ws from a common (single) through hole 43.

[0061] Furthermore, the portion of the winding W that forms each coil group 17 that is drawn out toward the second axial direction Da2 is a fixed end, which is the starting wire Ws. As mentioned above, the starting wire Ws has the characteristic that the position of the starting wire Ws does not vary much for each coil group 17, so it is possible to insert the starting wire Ws through the through hole 43 simply by placing the second busbar unit 5 on the stator 3. As a result, the process of adjusting the position of the starting wire Ws or locking the starting wire Ws somewhere is unnecessary, thus reducing the man-hours required for assembling the second busbar unit 5 to the stator 3. In addition, it is possible to draw out the starting wire Ws with high reproducibility to a position suitable for joining to the joint 52, that is, a position that passes through the through hole 43.

[0062] The exposed portion 44 is the part of the substrate portion 51 covered by the main body portion 41 that exposes only the joint portion 52, and is provided around the guide portion 43. In other words, it can be said that the guide portion 43 is attached to the exposed portion 44. Three exposed portions 44 are provided, corresponding to the number of guide portions 43.

[0063] The exposed portion 44 may be formed, for example, by hollowing out a part of the main body portion 41. In this embodiment, the exposed portion 44 is provided as a notch cut out (hollowed out) from the second axial direction Da2 side of the radially inner or radially outer portion (part of the main body portion 41) of the through hole 43 in the main body portion 41. The joint portion 52 of the substrate portion 51 is exposed in the second axial direction Da2 by such an exposed portion 44. Hereinafter, the exposed portion 44 will also be referred to as the notch 44.

[0064] In this embodiment, as described above, the joint portion 52 is positioned radially inward from the starting line Ws, so the notch 44 is provided adjacent to the radially inward side of the through hole 43. The notch 44 may be provided by cutting out the entire portion of the main body 41 that is radially inward from the through hole 43, for example, as shown in Figures 7 and 8. Alternatively, the notch 44 may be provided without cutting out the entire portion, leaving the portion of the main body 41 that is radially inward from the joint portion 52 intact.

[0065] The notch 44 may be provided in such a way that it exposes not only the surface of the joint 52 facing the second axial direction Da2, as shown in Figures 7 and 8, but also the radial side surface of the joint 52, or it may be provided in such a way that it exposes only the surface of the joint 52 facing the second axial direction Da2. The notch 44 may also be provided so as to penetrate the main body 41 in the axial direction. In this case, there is no clear boundary between the through hole 43 and the notch 44, and the through hole 43 is expanded by the notch 44.

[0066] The initial wire Ws, inserted through the through hole 43, is bent radially inward and guided into the space formed by the notch 44 (the space in which the main body portion 41 is partially hollowed out). In this way, the initial wire Ws is guided by the guide portion 43 to bend towards the exposed portion 44, so the guide portion 43 can also be described as the part that guides the bending of the initial wire Ws towards the exposed portion 44. Furthermore, by folding the initial wire Ws radially inward rather than radially outward, leakage current from the initial wire Ws to the housing 6 is prevented.

[0067] Subsequently, the initial wire Ws comes into contact with the joint 52, which is exposed in the second axial direction Da2 by the notch 44, from the second axial direction Da2 side. The initial wire Ws that comes into contact with the joint 52 is joined to the joint 52 by spot welding, which involves applying pressure from the second axial direction Da2 side to melt and bond the joint 52 and the initial wire Ws together, rather than by conventional manual soldering. This reduces the amount of work required to join the initial wire Ws to the busbar 50.

[0068] The joint 52, which is pressed in the first axial direction Da1 during spot welding, is supported by the base plate portion 51 covering the main body portion 41 of the holder 40 mounted on the stator 3. Therefore, movement of the joint 52 toward the first axial direction Da1 and the busbar 50 falling out are suppressed during spot welding. In addition, the portion of the main body portion 41 located toward the first axial direction Da1 than the notch 44 can also play a role in supporting the joint 52 from the first axial direction Da1 side during spot welding of the joint 52 and the starting wire Ws.

[0069] In other words, in this embodiment, the holder 40 mounted on the stator 3 is covered with a substrate portion 51, and a notch 44 (exposed portion 44) is provided that exposes the joint portion 52 of the substrate portion 51 in the second axial direction Da2, making it possible to join the joint portion 52 and the starting wire Ws by spot welding instead of conventional manual soldering. Furthermore, the portion of the winding W of each coil group 17 that is joined to the joint portion 52 is the starting wire Ws, which is less prone to variations in its pull-out position, and these starting wires Ws are always pulled out from the through hole 43, thus improving the reproducibility of the position of the starting wire Ws that will be spot-welded. Therefore, when automating the joining process of the starting wire Ws and incorporating it into the manufacturing process of the motor 1, it is possible to suppress the complexity of handling the starting wire Ws.

[0070] In this embodiment, the joint portion 52 of each busbar 50 is provided at a position excluding both ends in the extending direction of the substantially arc-shaped base plate portion 51, as shown in Figure 7. Furthermore, the notch 44 is provided such that only the joint portion 52 of the base plate portion 51 is exposed, and the portions adjacent to both sides of the joint portion 52 in the extending direction of the base plate portion 51 are not exposed from the main body portion 41. In other words, only the joint portion 52 of the base plate portion 51 is exposed in the second axial direction Da2, and the portions adjacent to both sides of the joint portion 52 are covered by the holder 40 without being exposed. As a result, the holding force of the busbar 50 during spot welding of the joint portion 52 and the starting wire Ws is increased, and detachment is suppressed.

[0071] The protrusion 42 is a portion for covering (embedding) the portion of the terminal portion 53 of each busbar 50 on the first axial direction Da1 side. The protrusion 42 is, for example, provided in the circumferential direction of the main body 41, projecting toward the second axial direction Da2 side from the point where the three terminal portions 53 meet.

[0072] [2. Function and Effects] (1) In the second busbar unit 5 described above, the holder 40 that covers the substrate portion 51 of the busbar 50 is provided with an exposed portion 44 and a guide portion 43. The conductor (starting wire Ws) to be joined to the joint portion 52, which is part of the substrate portion 51, is guided by the guide portion 43 to bend towards the exposed portion 44, and comes into contact with the joint portion 52 which is exposed by the exposed portion 44. As a result, the conductor can be joined to the joint portion 52 by spot welding instead of conventional manual soldering, thus reducing the man-hours required for joining the conductor.

[0073] (2) Furthermore, if a part of the main body portion 41 of the holder 40 is hollowed out to form an exposed portion 44, the wires can be placed in the hollowed-out space, thereby preventing the wires from coming into contact with other parts (for example, the end bell 7 located on the second axial direction Da2 side of the second busbar unit 5).

[0074] (3) In the second busbar unit 5 and motor 1 described above, the substrate portion 51 of the busbar 50 is covered by the holder 40, and the holder 40 is provided with an exposed portion 44 that exposes only the joint portion 52 of the substrate portion 51 in the first direction in the thickness direction of the substrate portion 51 (here, the second axis direction Da2), and a guide portion 43 that guides the conductor (starting wire Ws) from the second direction in the thickness direction (here, the first axis direction Da1) toward the first direction. As a result, the conductor guided by the guide portion 43 from the second direction toward the first direction can be brought into contact with the joint portion 52 exposed by the exposed portion 44 attached to the guide portion 43 from the first direction side, and the conductor and the joint portion 52 can be joined by spot welding.Therefore, the number of man-hours required for joining the conductor can be reduced compared to conventional manual soldering.

[0075] (4) If the substrate portions 51 of the multiple busbars 50 provided in the second busbar unit 5 are arranged to be on the same plane, the axial thickness of the main body portion 41 of the holder 40 of the second busbar unit 5, which is covered by the substrate portions 51, can be reduced. This makes it possible to make the second busbar unit 5 thinner, and consequently contributes to miniaturizing the device (in this case, the motor 1) to which the second busbar unit 5 is applied.

[0076] (5) If the joint portion 52 is provided in a position that excludes both ends in the extending direction of the base plate portion 51, and the portions adjacent to both sides of the joint portion 52 in the extending direction of the base plate portion 51 are covered by the holder 40 without being exposed, the joint portion 52 will be supported at both ends, which will increase the holding force of the bus bar 50 during spot welding and prevent the bus bar 50 from coming loose, so that the conductor can be joined to the joint portion 52 more appropriately.

[0077] (6) In the motor 1 described above, the initial wires Ws of the windings W that form each coil 16 (each coil group 17) of the stator 3 are all drawn out from the second axial direction Da2 side. The second busbar unit 5 has a holder 40 mounted on the second axial direction Da2 side of the stator 3. The guide portion 43 is provided as a through hole that penetrates axially and through which the initial wires Ws of each coil 16 (each coil group 17) are inserted, and the exposed portion 44 is provided as a notch on the radially inner side of the through hole 43 that exposes the joint portion 52 of the substrate portion 51 to the second axial direction Da2.

[0078] With this configuration, the assembly of the second busbar unit 5 to the stator 3 is completed simply by placing the holder 40 on the stator 3 while passing the initial wire Ws through the through hole 43, thus reducing assembly man-hours. Furthermore, since the portion of the winding W that forms each coil 16 (each coil group 17) that is joined to the busbar 50 of the second busbar unit 5 is the initial wire Ws, which is less prone to variation in its position, these initial wires Ws can be easily passed through the through hole 43 when placing the holder 40 on the stator 3, thus reducing assembly man-hours in this respect as well.

[0079] Furthermore, the joint portion 52 of the substrate portion 51 covering the holder 40 mounted on the stator 3 is exposed in the second axial direction Da2 by a notch 44, allowing the initial wire Ws inserted through the through hole 43 and the joint portion 52 to be joined by spot welding from the second axial direction Da2 side where the stator 3 is not present. Therefore, the number of man-hours required for connecting the initial wire Ws can be reduced compared to conventional manual soldering. In addition, since the initial wire Ws can be joined by spot welding instead of manual soldering, the initial wire Ws joining process can be automated and incorporated into the manufacturing process of the motor 1.

[0080] (7) In the second busbar unit 5 described above, the notch 44 is provided on the radially inward side of the through hole 43. This allows the initial wire Ws inserted through the through hole 43 to be folded radially inward, rather than radially outward, and brought into contact with the joint 52, thereby preventing leakage current from the initial wire Ws to the housing 6.

[0081] (8) If the starting wires Ws of the different two-phase coils 16 (coil group 17) connected by each busbar 50 of the second busbar unit 5 are drawn out from the same slot 15 so as to be adjacent in the circumferential direction, these starting wires Ws can be inserted together into a single through hole 43 and joined together to the joint 52 by spot welding. Thus, the assembly man-hours can be further reduced.

[0082] [3. Others] The configuration of the second busbar unit 5 and motor 1 described above is just one example and is not limited to the above configuration. For example, the motor 1 may be configured such that the second busbar unit 5, stator 3, and first busbar unit 4 are arranged in this order from the first axial direction Da1 to the second axial direction Da2. In this case, the "first direction" and "predetermined axial direction" described in the claim refer to the first axial direction Da1, and the "second direction" described in the claim refer to the second axial direction Da2. Note that the motor 1 does not have to be equipped with the first busbar unit 4.

[0083] The second busbar unit 5 does not have to be an insert molded product in which a plurality of busbars 50 are molded by a resin holder 40, but may be a structure in which a plurality of busbars 50 are assembled inside the resin holder 40 after the holder 40 has been molded. Similarly, the first busbar unit 4 does not have to be an insert molded product, but may be a structure in which a plurality of busbars 30 are assembled inside the resin holder 20 after the holder 20 has been molded. The end wire Wf may be joined to the busbars 30 of the first busbar unit 4 by soldering.

[0084] The windings W provided in the stator 3 do not necessarily form two adjacent coils 16 of the same phase; for example, they may form a single coil 16, or they may form four coils 16 of the same phase in a row. In other words, the number of windings W provided in the stator 3 is not limited to the six described above. The starting wires Ws of windings W that form coils 16 of different phases adjacent to each other in the circumferential direction do not necessarily have to be drawn from the same slot 15. The number of coils 16 provided in the stator 3 does not necessarily have to be twelve.

[0085] The busbar 50 of the second busbar unit 5 does not have to be a terminal electrically connected to an external power supply device, but may be a simple busbar (conductor) that electrically connects the terminal electrically connected to the external power supply device to each coil 16 (each coil group 17). In this case, the substrate portions 51 of the U-line busbar 50u, V-line busbar 50v, and W-line busbar 50w may be extended only around the joint portion 52 so as not to overlap in the circumferential direction.

[0086] The substrate portion 51 described in claim 1 of the claims may be at least substantially arc-shaped, but does not have to be plate-shaped. Similarly, the substrate portion 51 described in claim 3 of the claims may be at least plate-shaped, but does not have to be substantially arc-shaped. The joint portion 52 may be provided at the end of the plate-shaped substrate portion 51 in the extending direction.

[0087] The holder 40 of the second busbar unit 5 only needs to have a shape that can cover the substrate portion 51, and does not have to be annular. The holder 40 of the second busbar unit 5 may be, for example, arc-shaped, disc-shaped, fan-shaped, or rectangular, and the main body portion 41 of the holder 40 does not have to be plate-shaped when viewed from the radial direction.

[0088] The notch 44 provided in the holder 40 of the second busbar unit 5 may be provided radially outward of the through hole 43. The through hole 43 and notch 44 are not provided for all of the joint portions 52 of the three busbars 50 provided in the second busbar unit 5, but may be provided only for the joint portion 52 of one of the three busbars 50. If the two initial wires Ws connected by each busbar 50 of the second busbar unit 5 are drawn out at relatively distant positions in the circumferential direction, the through hole 43 and notch 44 may be provided to join each initial wire Ws to the base portion 51. That is, the through hole 43 does not have to be a hole that draws out both initial wires Ws together, and multiple through holes 43 and notches 44 may be provided for the base portion 51 of a single busbar 50.

[0089] The exposed portion 44 only needs to be a portion that exposes at least the joint portion 52 of the substrate portion 51, and does not have to be a notch cut out of the main body portion 41 from the first direction side (second axial direction Da2 side). The guide portion 43 does not have to be a through hole that penetrates the main body portion 41 in the axial direction. For example, the guide portion 43 may be a notch cut out of the main body portion 41 from the radially outer side so as to penetrate the main body portion 41 in the axial direction.

[0090] The busbar unit on which the guide portion 43 and exposed portion 44 are provided does not have to be a second busbar unit 5 that connects two different phases of coils 16 (coil group 17) from among the three phase coils 16 (coil group 17), but may also be a first busbar unit 4 that connects the three phase coils 16 (each coil group 17) according to their phase. The end wires Wf of the winding W may be joined to the busbar unit. The busbar unit only needs to have at least a conductor joined to it, and the conductor does not have to be the winding W provided on the stator 3.

[0091] If a busbar unit is provided with multiple busbars, the plate-shaped substrate portions of these busbars may partially overlap in the thickness direction. Furthermore, a busbar unit does not necessarily have to consist of multiple busbars.

[0092] 1 Motor (brushless motor) 1s Shaft 2 Rotor 3 Stator 5 Second busbar unit (busbar unit) 15 Slot 16 Coil 16u U-phase coil (coil) 16v V-phase coil (coil) 16w W-phase coil (coil) 17 Coil group (coil) 17u U-phase coil group (coil) 17v V-phase coil group (coil) 17w W-phase coil group (coil) 40 Holder 41 Main body 43 Through hole (guide part) 44 Notch (exposed part) 50 Busbar 50u U-line busbar (busbar) 50v V-line busbar (busbar) 50w W-line busbar (busbar) 51 Substrate part 52 Joint part (part of substrate part) Da1 First axis direction (second direction) Da2 Second axis direction (first direction, predetermined axis direction) W Winding (conductor) Ws Starting wire (conductor)

Claims

1. A busbar unit comprising: a busbar having a substantially arc-shaped substrate portion; and a non-conductive holder covering the substrate portion, wherein the holder has an exposed portion that exposes a part of the substrate portion; and a guide portion that guides the bending of a conductor joined to the part towards the exposed portion.

2. The busbar unit according to claim 1, characterized in that the exposed portion is formed by removing material from a part of the main body of the holder.

3. A busbar unit comprising: a conductive busbar having a plate-shaped substrate portion; and a resin holder covering the substrate portion, wherein the holder has an exposed portion that exposes only a part of the substrate portion in a first direction in the thickness direction of the substrate portion; and a guide portion attached to the exposed portion that guides a conductor joined to the part toward the first direction from a second direction opposite to the first direction.

4. The busbar unit according to claim 3, characterized in that a plurality of busbars are provided, and the substrate portions of the plurality of busbars are located on the same plane.

5. The busbar unit according to claim 3, characterized in that the part is provided at positions excluding both ends in the extending direction of the substrate, and the portions of the part on the substrate adjacent to both sides in the extending direction are covered by the holder without being exposed.

6. A busbar unit according to any one of claims 3 to 5, applicable to an inner rotor type brushless motor comprising an annular stator and a rotor located radially inward of the stator, wherein the conductor is the starting wire of a winding forming the coil of the stator and is drawn out on a predetermined axial side in the axial direction of the stator, the holder is placed on the predetermined axial side of the stator with the first direction aligned along the predetermined axial direction, the guide portion is a through hole that penetrates in the axial direction and through which the starting wire is inserted, and the exposed portion is a notch that exposes a part of the substrate portion in the predetermined axial direction on the inner side of the through hole or on the radially outward side.

7. The busbar unit according to claim 6, characterized in that the notch is provided on the inner side of the through hole.

8. A brushless motor comprising: a busbar unit according to claim 6; a stator on which the busbar unit is mounted; and a rotor that rotates integrally with a shaft on the inner side of the stator.

9. The brushless motor according to claim 8, wherein the stator is provided with three-phase coils, the busbars are terminals that connect two different phases of the three-phase coils and are electrically connected to an external power supply device, and a plurality of busbars are provided, the holder has the same number of through holes and notches as the busbars, and the start wires of the windings that form each of the two different phases of coils connected by each busbar are drawn out from the same slot in the predetermined axial direction, inserted through a common through hole, and joined to a part of the busbar.

Images