Busbar unit and brushless motor

Abstract

The bus bar unit (4) includes a bus bar (50) having a substantially arc-shaped substrate portion (51) and a non-conductive holder (40) covering the substrate portion (51). The holder (40) has an exposed portion (44) exposing a part (52) of the substrate portion (51) and a guide portion (43) guiding bending of a wire (Ws) connected to the part (52) toward the exposed portion (44). Alternatively, the bus bar unit (4) can include a bus bar (50) having a plate-shaped substrate portion (51) and a resin holder (40) covering the substrate portion (51). The holder (40) can have an exposed portion (44) exposing only the part (52) of the substrate portion (51) toward a first direction (Da2) and a guide portion (43) guiding a wire (Ws) to be joined to the part (52) from a second direction (Da1) toward the first direction (Da2).

Description

TECHNICAL FIELD

[0001] The present application relates to a bus bar unit and a brushless motor provided with the bus bar unit. BACKGROUND

[0002] In the past, a motor has been known in which a wire of a coil built therein is joined to a bus bar of electric conductivity by soldering (for example, Patent Literature 1).

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2024-123482 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the motor provided with the stator disclosed in Patent Literature 1, it is sometimes necessary to perform soldering for joining the wire to the bus bar by manual work, and thus there is room for improvement in that the man-hours involved in the joining are increased. Note that the above problem is a problem that occurs in the case of joining the wire to the bus bar, and is not limited to the case where the wire is a wire (winding wire) of a coil, and is also not limited to the case where the device provided with the bus bar is a motor, a stator.

[0008] The present application is made in view of such a problem, and one of the objects thereof is to provide a bus bar unit and a brushless motor capable of reducing man-hours involved in joining a wire to a bus bar. Note that the object is not limited thereto, and an effect derived from each structure shown in the detailed description below, and an effect that cannot be obtained by the conventional technology are also another object of the present application.

[0009] SOLUTIONS TO THE PROBLEMS

[0010] The bus bar unit and the brushless motor of the present disclosure can be implemented as the following disclosed solutions (application examples) that solve at least a part of the above problems. Note that Solution 3 is a solution that can be appropriately selected in addition to the other bus bar units of Solution 2, and both are solutions that can be omitted. That is, Solution 3 does not disclose a solution or a structure that is necessary and indispensable to the other bus bar units of the present application.

[0011] Solution 1. The bus bar unit of the present disclosure is provided with a bus bar having a substantially arc-shaped substrate portion, and a non-conductive holder that covers the substrate portion, the holder having an exposed portion that exposes a part of the substrate portion, and a guide portion that guides bending of a wire connected to the part toward the exposed portion.

[0012] The busbar unit of the present disclosure includes a busbar having a plate-shaped substrate portion and a resin-made holder covering the substrate portion. The holder has an exposed portion exposing only a portion of the substrate portion in a first direction in a plate thickness direction of the substrate portion, and a guide portion attached to the exposed portion and guiding a wire to be joined to the portion from a second direction opposite to the first direction toward the first direction.

[0013] In the busbar unit of the present disclosure, the busbar is applied to an inner rotor type brushless motor having a ring-shaped stator and a rotor located on an inner side in a radial direction of the stator. The wire is a start wire of a winding forming a coil of the stator, and is drawn out to a prescribed axial side in an axial direction of the stator. The holder is placed on the prescribed axial side of the stator in a state where the first direction is along the prescribed axial direction. The guide portion is a through-hole penetrating in the axial direction and through which the start wire passes. The exposed portion is a notch exposing the portion of the substrate portion in the prescribed axial direction on the inner side of the through-hole or an outer side in the radial direction.

[0014] The brushless motor of the present disclosure includes the busbar unit of the present disclosure, the stator on which the busbar unit is placed, and the rotor rotating integrally with a shaft on the inner side of the stator.

[0015] Effects of Invention

[0016] According to the busbar unit and the brushless motor of the present disclosure, the work hours involved in joining the wire to the busbar can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is an exploded perspective view of a brushless motor to which the busbar unit according to the embodiment is applied.

[0018] Figure 2 is a perspective view of a stator included in the brushless motor of Figure 1

[0019] Figure 3 is a diagram schematically showing a wiring method and a connection method of a winding forming a coil of the stator included in Figure 2

[0020] Figure 4 is a diagram for explaining characteristics of a start wire and an end wire of a winding, and is a perspective view showing a portion of a core unit of a stator and a winding wound around the portion.

[0021] ​​Figure 5 is a perspective view obtained when observing the first bus bar unit and the stator provided in the brushless motor from a first axial direction. Figure 1

[0022] Figure 6 is a perspective view obtained when observing the first bus bar unit from a second axial direction. Figure 5

[0023] Figure 7 is a perspective view obtained when observing the second bus bar unit and the stator provided in the brushless motor from a second axial direction. Figure 1

[0024] Figure 8 is an X-X cross-sectional view of the second bus bar unit. Figure 7 DETAILED DESCRIPTION

[0025] A bus bar unit and a brushless motor as embodiments will be described with reference to the drawings. The embodiments shown below are merely examples and are not intended to exclude various modifications and technical applications not explicitly shown in the following embodiments. The structures of the present embodiments can be modified in various ways without departing from the spirit thereof.

[0026] The bus bar unit is provided with a bus bar having a substantially arc-shaped substrate portion and a non-conductive holder covering the substrate portion. The holder is provided with an exposed portion exposing a part of the substrate portion and a guide portion guiding the bending of a wire joined to the part toward the exposed portion.

[0027] Alternatively, the bus bar unit is provided with a conductive bus bar having a plate-shaped substrate portion and a resin holder covering the substrate portion. The holder is provided with an exposed portion exposing only a part of the substrate portion in one direction (first direction) of the plate thickness direction of the substrate portion and a guide portion guiding a wire joined to the part. The guide portion is attached to the exposed portion and guides the wire from a second direction (the other direction of the plate thickness direction) opposite to the first direction toward the first direction.

[0028] With the above structure, the wire guided by the guide portion can be brought into abutment with the part of the substrate portion and joined to the bus bar by spot welding, which contributes to the reduction of man-hours. The bus bar unit described in detail below is applied to a brushless motor as an example, but the application object of the bus bar unit described above is not limited to a motor and can be various electrical devices such as a switchboard, a storage battery, a generator, and the like.

[0029] [1. Structure]

[0030] [1-1. Overall structure] ​​​​

[0031] Figure 1 FIG. 1 is an exploded perspective view of a brushless motor 1 (hereinafter also referred to as "motor 1") to which the bus bar unit according to the present embodiment is applied. The brushless motor 1 according to the present embodiment is a brushless motor of an inner rotor type, as shown in FIG. 1, and includes a rotor 2 that rotates integrally with a shaft Is, a stator 3, and bus bar units 4, 5. The motor 1 is configured by housing the rotor 2, the stator 3, and the bus bar units 4, 5 in a bottomed cylindrical housing 6. An end cover 7 as a cover member can be combined on the opening side (left side in the drawing) of the housing 6. Figure 1

[0032] Hereinafter, the direction of extension of the shaft Is (the direction of the axis line C of the shaft Is) is referred to as the axial direction. The direction in the axial direction in which the bottom of the housing 6 is located with respect to the opening of the housing 6 (the right side in the drawing of FIG. 1) is referred to as the first axial direction Dal, and the direction opposite to the first axial direction Dal is referred to as the second axial direction Da2 (the prescribed axial direction). The direction orthogonal to the axial direction and away from the axis line C and the direction toward the axis line C are referred to as the radial direction. The direction in the radial direction away from the axis line C is referred to as the radially outer side (the outer side), and the direction toward the axis line C is referred to as the radially inner side (the inner side). The direction orthogonal to the axial direction and encircling the axis line C is referred to as the circumferential direction. The direction in the circumferential direction that is clockwise when viewed from the first axial direction Dal side is referred to as the first circumferential direction Dcl, and the direction opposite to the first circumferential direction Dcl (the counterclockwise direction) is referred to as the second circumferential direction Dc2. Figure 1 The motor 1 illustrated here includes, as shown in FIG. 1, the rotor 2, the stator 3, and the bus bar units 4, 5. The rotor 2 is a rotating body that rotates integrally with the shaft Is. The stator 3 is a stationary body that is fixed to the housing 6 and generates a rotating magnetic field in cooperation with the rotor 2. The bus bar units 4, 5 are electrically connected to the stator 3 and the rotor 2, and supply electric power to the stator 3 and the rotor 2.

[0033] Figure 1 The motor 1 illustrated here includes, as shown in FIG. 1, the rotor 2, the stator 3, and the bus bar units 4, 5. The rotor 2 is a rotating body that rotates integrally with the shaft Is. The stator 3 is a stationary body that is fixed to the housing 6 and generates a rotating magnetic field in cooperation with the rotor 2. The bus bar units 4, 5 are electrically connected to the stator 3 and the rotor 2, and supply electric power to the stator 3 and the rotor 2.

[0034] [1-2. Rotor]

[0035] The rotor 2 includes, for example, a rotor core that rotates integrally with the shaft Is and a plurality of magnets embedded in the rotor core. The shaft Is is a rotating shaft that supports the rotor 2 and functions also as an output shaft that takes out the output (mechanical energy) of the motor 1 to the outside. The shaft Is is supported by the bottom of the housing 6 and the end cover 7 so as to be rotatable, for example, via bearings 8 that sandwich the rotor core in the axial direction at two positions.

[0036] ​​[1-3. Stator]

[0037] The stator 3 is a ring-shaped member having a space in which the rotor 2 is disposed on the radially inner side, and is disposed concentrically with the axis C. Therefore, the axial direction, the radial direction, and the circumferential direction of the axis C described above can also be referred to as the axial direction, the radial direction, and the circumferential direction of the stator 3, respectively. The outer shape of the stator 3 of the present embodiment is a circular ring shape (cylindrical shape), but the shape of the stator 3 is not limited thereto.

[0038] As shown in Figure 2 , the stator 3 includes a substantially cylindrical core unit 11 and a plurality of coils 16. The core unit 11 is, for example, a molded product in which a stator core is molded with resin as an insulating member, and is fixed in the housing 6. The core unit 11 has a cylindrical outer peripheral wall 12, a plurality of teeth 13 provided so as to protrude toward the radially inner side from the inner peripheral surface of the outer peripheral wall 12, and a circular arc-shaped inner peripheral wall 14 provided so as to extend in the circumferential direction on the radially inner side of each tooth 13. The plurality of teeth 13 are separated from each other in the circumferential direction and are provided at equal intervals. A number of slots 15 equal to the number of teeth 13 are formed between the plurality of teeth 13. The coils 16 are formed by winding wire W around each of the plurality of teeth 13, and are provided in a number equal to the number of teeth 13.

[0039] As shown in Figure 2 and Figure 3 , twelve teeth 13, twelve slots 15, and twelve coils 16 are provided in the stator 3 of the present embodiment, respectively. Four U-phase coils 16u, four V-phase coils 16v, and four W-phase coils 16w are provided in the stator 3, respectively, as the twelve coils 16. The U-phase coils 16u are supplied with a current of the U-phase, the V-phase coils 16v are supplied with a current of the V-phase, and the W-phase coils 16w are supplied with a current of the W-phase.

[0040] Note that, in Figure 2 , only two teeth 13 adjacent in the circumferential direction among the twelve teeth 13 are illustrated using dotted lines. In addition, only one slot 15 formed between the two teeth 13 illustrated among the twelve slots 15 is labeled with a reference numeral. In Figure 3 , only a part of the twelve teeth 13 and the twelve slots 15, respectively, are labeled with reference numerals.

[0041] For example, as shown in Figure 2As shown, on the stator 3, the U-phase coils 16u, the V-phase coils 16v, and the W-phase coils 16w are arranged in parallel in the circumferential direction in groups of two each. That is, two of the four U-phase coils 16u are arranged adjacent to each other in the circumferential direction, two V-phase coils 16v are arranged adjacent to each other in the circumferential direction on the second circumferential direction Dc2 side of the two U-phase coils 16u. Further, two W-phase coils 16w are arranged adjacent to each other in the circumferential direction on the second circumferential direction Dc2 side of the two V-phase coils 16v, and the remaining two of the four U-phase coils 16u are arranged adjacent to each other in the circumferential direction on the second circumferential direction Dc2 side of the two W-phase coils 16w. The remaining two V-phase coils 16v are arranged adjacent to each other in the circumferential direction on the second circumferential direction Dc2 side of the remaining two U-phase coils 16u, and the remaining two W-phase coils 16w are arranged adjacent to each other in the circumferential direction on the second circumferential direction Dc2 side of the remaining two V-phase coils 16v.

[0042] Hereinafter, the two coils 16 of the same phase that are arranged adjacent to each other will be collectively referred to as a coil group 17. The stator 3 having twelve coils 16 can also be expressed as having two U-phase coil groups 17u, two V-phase coil groups 17v, and two W-phase coil groups 17w. Further, with regard to the arrangement of the coils 16 described above, the U-phase coil groups 17u, the V-phase coil groups 17v, and the W-phase coil groups 17w are arranged in the circumferential direction on the stator 3 in that order, and can also be expressed as being arranged so that the two coil groups 17 of each phase face each other with the axis C therebetween.

[0043] In the present embodiment, as shown in FIG. 1, the coils 16 are arranged on the stator 3 so that the coils 16 of the same phase are arranged adjacent to each other in the circumferential direction. That is, the coils 16 of the same phase are arranged in the circumferential direction in groups of two each. Figure 3 As shown, each coil group 17 is formed by one continuous wire W. That is, six wires W are provided on the stator 3, and each wire W is wound around two teeth 13 adjacent to each other in the circumferential direction, thereby forming each coil group 17. In detail, the wire W forming each coil group 17 is not cut after being wound around one of the two teeth 13 adjacent to each other in the circumferential direction, but is wound around the other of the two teeth 13. The wire W forming each coil group 17 can be laid (wired) so that the winding direction with respect to one of the teeth 13 and the winding direction with respect to the other of the teeth 13 are opposite, as shown.

[0044] One of the start line Ws and the end line Wf of each wire W is drawn to the first axial direction Dal side, and the other is drawn to the second axial direction Da2 side. In the present embodiment, as shown in FIG. 1, the start lines Ws of the six wires W are all drawn to the second axial direction Da2 side, and the end lines Wf of the six wires W are all drawn to the first axial direction Dal side. The six start lines Ws drawn to the second axial direction Da2 side are joined (connected) to the bus bars 50 of the second bus bar unit 5 described later, and the six end lines Wf drawn to the first axial direction Dal side are joined (connected) to the bus bars 30 of the first bus bar unit 4 described later. Figure 3 ​

[0045] Among the six starting wires Ws led to the second axial Da2 side, the starting wires Ws of the windings W forming the adjacent coil group 17 can be led from the same (common) slot 15 as each other. In the present embodiment, two starting wires Ws are each led from three slots 15 arranged at every third slot in the circumferential direction. Likewise, among the six ending wires Wf led to the first axial Da1 side, the ending wires Wf of the windings W forming the adjacent coil group 17 can be led from the same slot 15 as each other. In the present embodiment, two ending wires Wf are each led from three slots 15 arranged at every third slot in the circumferential direction. The starting wire Ws and the ending wire Wf of each winding W can be led from different slots 15 as shown, or can be led from the same slot 15. Figure 3

[0046] Note that the starting wire Ws here means the portion where the winding W (conductor) forming each coil group 17 starts to be wound, and the ending wire Wf means the portion where the winding W (conductor) forming each coil group 17 ends to be wound. The electricity supplied to each coil group 17 can flow from the starting wire Ws toward the ending wire Wf, or from the ending wire Wf toward the starting wire Ws. Therefore, the starting wire Ws and the ending wire Wf are defined regardless of the direction of flow of the electricity supplied to each coil group 17.

[0047] Figure 4 is a perspective view showing a portion of the core unit 11 that is an example for explaining the characteristics of the starting wire Ws and the ending wire Wf of the winding W, and the winding W wound around the portion. In Figure 4 , as a portion of the core unit 11, the core unit 11 is divided into twelve in the circumferential direction, and only one of the twelve divided cores 11n is illustrated. The core unit 11 can be configured by combining a plurality of divided cores 11n divided at equal intervals in the circumferential direction as such.

[0048] In addition, as described above, in the stator 3 of the present embodiment, the case where one winding W is continuously wound around two adjacent teeth 13 to form one coil group 17 composed of two coils 16 of the same phase is explained. However, in Figure 4 , a case where one winding W is wound around only one divided core 11n (one tooth) to form one coil 16 is illustrated. The stator 3 can also be provided with the same number of windings W as the number of teeth 13 as such.

[0049] As described above, in the stator 3 of the present embodiment, the case where one winding W is continuously wound around two adjacent teeth 13 to form one coil group 17 composed of two coils 16 of the same phase is explained. However, in Figure 4 ​As shown, the start wire Ws of the winding wire W is restrained and fixed by the connection wire Wc by winding the connection wire Wc that connects the start wire Ws and the end wire Wf on the tooth. The start wire Ws of the winding wire W that forms each coil group 17 is fixed like this, and thus has a characteristic that the position of the start wire Ws in the radial direction is less likely to deviate (less play) for each coil group 17. On the other hand, the end wire Wf of the winding wire W that is the end portion of the winding is not restrained by the connection wire Wc, and thus has a characteristic that is highly free to be drawn out to the first axial Da1 side and to the inner side in the radial direction, or to be drawn out to the first axial Da1 side and to the outer side in the radial direction. Due to these characteristics, the start wire Ws can also be said to be a fixed end of the winding wire W, and the end wire Wf can also be said to be a free end of the winding wire W.

[0050] [1-4. First bus bar unit]

[0051] The first bus bar unit 4 is a member that is placed on the first axial Da1 side of the stator 3 and wires the coils 16 of the three phases in the same phase, as shown in Figure 5 It has a resin-made holder 20 and a plurality of bus bars 30. Each bus bar 30 is an electrically conductive member that wires the coils 16 of the three phases in the same phase, is disposed extending along the circumferential direction, and is covered by the holder 20 (buried in the holder 20). That is, the first bus bar unit 4 is provided as an insert-molded product in which the resin-made holder 20 and the components, or the resin-made holder 20, are molded around the plurality of bus bars 30. Note that the "disposed extending along" in the present embodiment is not limited to the case of being disposed extending in a direction (for example, the circumferential direction) that coincides with (is parallel to) the reference direction, but also includes the case of being disposed extending in a direction that is inclined with respect to the reference direction.

[0052] In the present embodiment, the end wires Wf of the two U-phase coil groups 17u, the end wires Wf of the two V-phase coil groups 17v, and the end wires Wf of the two W-phase coil groups 17w are drawn out to the first axial Da1 side. Therefore, as shown in Figure 3 and Figure 5 In the first bus bar unit 4, there are provided three bus bars 30 that wire the end wires Wf of the two U-phase coil groups 17u to each other, the end wires Wf of the two V-phase coil groups 17v to each other, and the end wires Wf of the two W-phase coil groups 17w to each other.

[0053] The three bus bars 30 are, for example, as shown in Figure 5As shown, the three busbars 30 are positioned at the same axial position (i.e., on the same plane) relative to the retainer 20 without overlapping when viewed axially. The three busbars 30 can all be of the same shape. Each busbar 30 can be positioned such that the first portion 31 on the first circumferential Dc1 side is located radially inward than the second portion 32 on the second circumferential Dc2 side. The three busbars 30 are, for example, formed as long strips extending spirally circumferentially and are configured to be rotationally symmetrical about axis C. Figure 3 As shown, the first part 31 and the second part 32 of each busbar 30 are respectively configured to overlap axially with the slot 15 of each of the end wires Wf of the two coil groups 17 of the phase to which the busbar 30 is connected, and are respectively engaged with these end wires Wf.

[0054] The first portion 31 of each busbar 30 and the second portion 32 of any other busbar 30 can be as follows: Figure 5 As shown, they are configured to overlap each other when viewed radially. In other words, the first portion 31 of each busbar 30 (e.g., U-phase busbar 30u) is configured to overlap with the second portion 32 of other busbars 30 (e.g., V-phase busbar 30v) that are connected to the coil group 17 of a phase different from that of the busbar 30 (e.g., U-phase coil group 17u) (e.g., V-phase coil group 17v).

[0055] The end wires Wf of different phase coil groups 17 drawn from the same slot 15 (e.g., the end wire Wf of U-phase coil group 17u and the end wire Wf of V-phase coil group 17v) are respectively drawn out radially inward and radially outward before the first busbar unit 4 is mounted relative to the stator 3. As described above, the portion of the winding W forming each coil group 17 that is drawn to the first axial direction Da1 side is the end wire Wf that becomes a free end, so such hooking of the winding W can be easily implemented. 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.

[0056] After the first busbar unit 4 is mounted relative to the stator 3, the last wire Wf of the last wire Wf led out from the same slot 15 that is led to the radially inner side (e.g., the last wire Wf of the U-phase coil group 17u) is folded towards the first axial direction Da1 and towards the radially outer side. Then, the last wire Wf (e.g., the last wire Wf of the U-phase coil group 17u) is joined from the first axial direction Da1 side to the first portion 31 of the busbar 30 (e.g., the U-phase busbar 30u) arranged such that the slot 15 from which the last wire Wf is led out overlaps with the first portion 31 by spot welding or brazing.

[0057] Conversely, the last wire Wf of the last wire Wf leading out from the same slot 15 that is radially outward (e.g., the last wire Wf of the V-phase coil group 17v) is folded towards the first axial direction Da1 and radially inward after the first busbar unit 4 is mounted relative to the stator 3. Then, the last wire Wf is joined from the first axial direction Da1 side to the second portion 32 of the busbar 30 (e.g., the V-phase busbar 30v) arranged such that the slot 15 from which the last wire Wf is led out overlaps with the second portion 32 by spot welding or brazing.

[0058] Therefore, the end wires Wf of different phases drawn from the common slot 15 can be joined to each other in the busbar 30 without crossing. This prevents the end wires Wf from contacting each other (energizing) and makes it easy to perform the joining process of the end wires Wf relative to the busbar 30.

[0059] As described above, the retainer 20 is a resin component covering the busbars 30 and is mounted on the stator 3. In this embodiment, the retainer 20 is annular. The retainer 20 has a main body 21, which is annular when viewed axially and flat when viewed radially. The three busbars 30 are covered by the main body 21. It should be noted that, as Figure 5 As shown, on the main body 21, three notches that expose a portion of the first portion 31 of the three busbars 30 can be provided radially inward. Additionally, three notches that expose a portion of the second portion 32 of the three busbars 30 can be provided radially outward.

[0060] like Figure 6 As shown, the retainer 20 may also be provided with an outer wall portion 22 extending from the outer periphery of the main body portion 21 toward the second axial direction Da2, and an inner wall portion 23 extending from the inner periphery of the main body portion 21 toward the second axial direction Da2. Multiple grooves may also be recessed on the end face of the main body portion 21 on the second axial direction Da2 side. These grooves, the outer wall portion 22, and the inner wall portion 23 can be used for temporary positioning of each segmented core 11n when the core unit 11 is composed of multiple segmented cores 11n.

[0061] [1-5. Second busbar unit]

[0062] The second busbar unit 5 is a component that connects the three-phase coils 16 in a delta connection manner (delta connection method), such as... Figure 7 As shown, it has a retainer 40 and a busbar 50. The retainer 40 is a non-conductive component, for example, made of resin. Figure 7 as well as Figure 8As shown, the busbar 50 is a conductive component having a substrate portion 51 that is plate-shaped when viewed radially and generally arc-shaped when viewed axially, and the substrate portion 51 is covered by a retainer 40 (embedded in the retainer 40). In other words, the second busbar unit 5 is configured as an embedded molded article formed by molding the busbar 50 using a resin retainer 40 and components, or a resin retainer 40.

[0063] For the second busbar unit 5, the retainer 40 is mounted on the second axial direction Da2 side of the stator 3 with one of the thickness directions (first direction) of the substrate portion 51 aligned with the second axial direction Da2. In this embodiment, the second busbar unit 5 is mounted on the second axial direction Da2 side of the stator 3 with the first direction in the thickness direction of the substrate portion 51 aligned with the second axial direction Da2. That is, in this embodiment, the second axial direction Da2 corresponds to the "first direction" described in the technical solution, and the first axial direction Da1 corresponds to the "second direction" described in the technical solution.

[0064] In this embodiment, multiple busbars 50 are provided to connect two different phases of the three-phase coils 16. On the second axial Da2 side of the stator 3 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. 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.

[0065] 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.

[0066] Furthermore, in this embodiment, each busbar 50 is configured as a terminal for electrical connection to an external power supply device (not shown). Therefore, each busbar 50 also has a terminal portion 53 for connection to an external power supply device.

[0067] The substrate portion 51, for example, is in the form of a generally arcuate shape extending along the circumferential direction (i.e., a direction orthogonal to the thickness direction). Figure 8 As shown, the three substrate portions 51 are disposed at the same axial position and do not overlap each other when viewed from the axial direction, that is, they are disposed on the same plane.

[0068] The start wire Ws of each coil group 17 is joined to a part of the substrate portion 51. Hereinafter, the part of the substrate portion 51 of each bus bar 50, which is joined to the start wire Ws, will be referred to as a joint portion 52. As shown in Figure 3 the U-line bus bar 50u, the V-line bus bar 50v, and the W-line bus bar 50w can be the start wires Ws of the coil groups 17 of different phases, respectively, and the start wires Ws drawn out from the common slot 15 are wired to each other. In correspondence thereto, the joint portion 52 of each bus bar 50 can be provided so as to overlap the slot 15 from which the start wire Ws wired through the bus bar 50 is drawn out in the axial direction.

[0069] In the present embodiment, as described above, the start wire Ws of each coil group 17 is drawn out from three slots 15 arranged at every three in the circumferential direction. Therefore, as shown in Figure 7 the three joint portions 52 are provided at equal intervals in the circumferential direction and separated from each other in a manner of overlapping each of the three slots 15, respectively. The three joint portions 52 are arranged, for example, at positions located radially inward of 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 joint portions 52 are set to substantially the same positions, respectively. Note that, in Figure 7 , a state in which the start wire Ws is drawn out to the second axial direction Da2 side is illustrated.

[0070] The terminal portion 53 is provided, for example, in a flat plate shape that stands up from the end portion of the substrate portion 51 in the direction of extension and is provided toward the second axial direction Da2 side. For example, as shown in Figure 7 the three terminal portions 53 can be concentrated at one portion in the circumferential direction and arranged separated from each other. In the present embodiment, the three terminal portions 53 are concentrated between the joint portion 52 of the U-line bus bar 50u and the joint portion 52 of the V-line bus bar 50v.

[0071] The substrate portion 51 of the U-line bus bar 50u, which is located on the second circumferential direction Dc2 side of the collection portion of the three terminal portions 53, is provided so as to extend in conformity with the circumferential direction, and the terminal portion 53 is provided in connection with the end portion on the first circumferential direction Dc1 side thereof. In addition, the substrate portion 51 of the V-line bus bar 50v, which is located on the first circumferential direction Dc1 side of the collection portion of the three terminal portions 53, is provided so as to extend in conformity with the circumferential direction, and the terminal portion 53 is provided in connection with the end portion on the second circumferential direction Dc2 side thereof.

[0072] On the other hand, the base plate portion 51 of the W-line busbar 50w, located at a position far from the junction of the three terminal portions 53, extends in a circumferential manner near the junction portion 52, but extends radially outward as it approaches the first circumferential Dc1 side (approaching the terminal portion 53 as it moves away from the junction portion 52). 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 on its first circumferential Dc1 side, so as not to interfere with the base plate portion 51 of the U-line busbar 50u. Specifically, the base plate portion 51 of the W-line busbar 50w, sandwiching the starting line Ws connected to the U-line busbar 50u, is arranged radially parallel to the base plate portion 51 of the U-line busbar 50u. A terminal portion 53 is connected to the end of the base plate portion 51 of the W-line busbar 50w on the first circumferential Dc1 side.

[0073] By arranging each substrate portion 51 of the U-line busbar 50u, V-line busbar 50v, and W-line busbar 50w as described above, these substrate portions 51 can be arranged at the same axial position in a manner that does not overlap in the axial direction. In other words, these substrate portions 51 can be arranged on the same plane in a manner that does not overlap in the axial direction.

[0074] As described above, the retainer 40 is a resin component that covers the base plate portion 51 of the busbar 50 and is mounted on the stator 3. The retainer 40 in this embodiment has a main body portion 41 and a protrusion 42.

[0075] The main body 41 is the portion of the base plate 51 that covers each busbar 50. For example, it is annular when viewed from the axial direction and flat when viewed from the radial direction. The main body 41 is provided with an exposed portion 44 that exposes only the joint portion 52 of the base plate 51 and a guide portion 43 that guides the starting wire Ws that is joined to the joint portion 52, as part of a structure that reduces the time involved in assembling the second busbar unit 5 with respect to the stator 3 and joining the starting wire Ws (conductor) with respect to the busbar 50.

[0076] In this embodiment, such as Figure 8 As shown, the guide portion 43 is configured as a through hole that extends axially through the main body portion 41. Hereinafter, the guide portion 43 will also be referred to as the through hole 43. When the second busbar unit 5 is mounted on the stator 3, the starting line Ws passes through the through hole 43 from the first axial direction Da1 toward the second axial direction Da2. Therefore, the guide portion 43 can also be described as the part that guides the starting line Ws from the first axial direction Da1 toward the second axial direction Da2.

[0077] The through hole 43 is provided at a position overlapping the start line Ws in the axial direction, in other words, at a position overlapping the slot 15 from which the start line Ws is led out. In the present embodiment, the start line Ws is led out from three portions in the circumferential direction (three slots 15 arranged every third slot in the circumferential direction), and therefore the through hole 43 is provided with three. As described above, the joint portion 52 of each bus bar 50 is provided at a position overlapping the common slot 15 from which the start line Ws to which the bus bar 50 is connected is led out in the axial direction. Therefore, it can also be said that the three through holes 43 are each provided at the same position in the circumferential direction as the joint portion 52 of the three bus bars 50.

[0078] The start lines Ws of the different phase coil groups 17 to which each bus bar 50 is connected are led out from the common slot 15 and engaged with the joint portion 52 of the bus bar 50 by passing through the common through hole 43 as shown in FIG. 6. In other words, the start lines Ws of the different phase coil groups 17 connected by each bus bar 50 are led out from the common slot 15 in a manner adjacent in the circumferential direction, and therefore two start lines Ws can be led out from the common (one) through hole 43. Figure 7

[0079] In addition, the portions of the wire Ws forming each coil group 17 that are led out to the second axial direction Da2 side are each a start line Ws that is a fixed end. As described above, the start line Ws has the characteristic that the position of the start line Ws does not easily deviate for each coil group 17, and therefore the start line Ws can be caused to pass through the through hole 43 simply by placing the second bus bar unit 5 on the stator 3. Therefore, there is no need for a process of adjusting the position of the start line Ws or latching the start line Ws somewhere, and therefore the working hours involved in the assembly of the second bus bar unit 5 with respect to the stator 3 can be reduced. In addition, the start line Ws can be led out to a position suitable for engagement with the joint portion 52, in other words, a position passing through the through hole 43, with high reproducibility.

[0080] The exposed portion 44 is a portion in which only the joint portion 52 of the substrate portion 51 covered by the main body portion 41 is exposed, and is provided at the periphery of the guide portion 43. That is, it can also be said that the guide portion 43 is attached to the exposed portion 44. The exposed portion 44 is provided with three corresponding to the number of the guide portions 43.

[0081] The exposed portion 44 can be formed, for example, by digging out a portion of the main body portion 41. In the present embodiment, the exposed portion 44 is provided as a notch formed by cutting out (digging out) a portion of the main body portion 41 on the radially inner side or radially outer side of the through hole 43 from the second axial direction Da2 side. The joint portion 52 of the substrate portion 51 is exposed to the second axial direction Da2 by the exposed portion 44. Hereinafter, the exposed portion 44 will also be referred to as the notch 44.

[0082] ​In the present embodiment, as described above, the joint portion 52 is configured to be located at a position that is radially inward of the start line Ws, and thus the notch 44 is provided adjacent to the radially inner side of the through-hole 43. For example, as shown in Figure 7 and Figure 8 shown, the notch 44 can also be provided to cut out the entire region of the portion of the main body portion 41 that is radially inward of the through-hole 43. Alternatively, the notch 44 can be provided in a manner that does not cut out this entire region, and leaves the portion of the main body portion 41 that is radially inward of the joint portion 52.

[0083] For example, as shown in Figure 7 and Figure 8 shown, the notch 44 can also be provided to expose not only the face of the joint portion 52 that faces the second axial direction Da2, but also the side face of the joint portion 52 that faces the radial direction, or can be provided to expose only the face of the joint portion 52 that faces the second axial direction Da2. Note that the notch 44 can also be provided to pass through the main body portion 41 in the axial direction. In this case, the clear boundary between the through-hole 43 and the notch 44 disappears, and the through-hole 43 is expanded by the notch 44.

[0084] The start line Ws that has passed through the through-hole 43 is bent radially inward, and is guided into the space (a space formed by the main body portion 41 being partially excavated) formed by the notch 44. In this way, the start line Ws is bent by the guide portion 43 toward the exposed portion 44, and thus the guide portion 43 can also be said to be a portion that guides the start line Ws toward the bend of the exposed portion 44. Further, since the start line Ws is bent radially inward, rather than radially outward, it is possible to prevent the start line Ws from leaking electricity to the housing 6.

[0085] Then, the start line Ws comes into abutment with the joint portion 52 that is exposed to the second axial direction Da2 by means of the notch 44 from the second axial direction Da2 side. The start line Ws that is in abutment with the joint portion 52 is joined to the joint portion 52 by spot welding, in which the joint portion 52 and the start line Ws are pressed from the second axial direction Da2 side to cause them to melt and adhere, rather than by the existing soldering based on manual work. Thus, it is possible to reduce the working hours involved in joining the start line Ws to the bus bar 50.

[0086] The joint portion 52 that is pressed toward the first axial direction Dal during spot welding is supported by the base portion 51 of the main body portion 41 of the holder 40 that is placed on the stator 3. Thus, it is possible to suppress cases in which the joint portion 52 moves toward the first axial direction Dal during spot welding, or the bus bar 50 falls off. Note that the portion of the main body portion 41 that is located at a position that is radially inward of the notch 44 can also function to support the joint portion 52 from the first axial direction Dal during spot welding of the joint portion 52 and the start line Ws.

[0087] In other words, in this embodiment, the substrate portion 51 is covered by the retainer 4 mounted on the stator 3 and a notch 44 (exposed portion 44) is provided to expose the joint portion 52 of the substrate portion 51 to the second axial direction Da2, thereby enabling the joint portion 52 to be joined to the starting wire Ws by spot welding instead of the conventional brazing based on manual operation. In addition, 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 deviation in the lead-out position, and these starting wires Ws are always led out from the through hole 43, thus improving the reproducibility of the position of the starting wire Ws on the side where spot welding is performed. As a result, when the joining process of the starting wire Ws is automated and incorporated into the manufacturing process of the motor 1, the situation where the handling of the starting wire Ws becomes complicated can be prevented.

[0088] In this embodiment, such as Figure 7 As shown, the joint portion 52 of each busbar 50 is provided at a position other than the two ends in the extension direction of the generally arc-shaped base plate portion 51. Furthermore, regarding the notch 44, only the joint portion 52 is exposed in the base plate portion 51; the portions of the base plate portion 51 adjacent to the two sides of the joint portion 52 in the extension direction are not exposed from the main body portion 41. In other words, for the base plate portion 51, only the joint portion 52 is exposed towards the second axial direction Da2, while the portions adjacent to the two sides of the joint portion 52 are not exposed and are covered by the retaining member 40. Therefore, the retaining force of the busbar 50 during spot welding of the joint portion 52 to the starting line Ws is increased, thereby suppressing detachment.

[0089] The protrusion 42 is a portion used to cover (embed) the portion of the terminal portion 53 of each busbar 50 on the first axial Da1 side. For example, the protrusion 42 is provided to protrude from the assembly portion of the three terminal portions 53 toward the second axial Da2 side in the circumferential direction of the main body 41.

[0090] [2. Functions and Effects]

[0091] (1) In the second busbar unit 5 described above, the retaining member 40 covering the base plate portion 51 of the busbar 50 is provided with an exposed portion 44 and a guide portion 43. The wire (starting wire Ws) that is joined to the joint portion 52, which is part of the base plate portion 51, is guided by the guide portion 43 to the bend of the exposed portion 44 and abuts against the joint portion 52 exposed by the exposed portion 44. As a result, the wire can be joined to the joint portion 52 by spot welding instead of the existing brazing based on manual operation, thus reducing the time involved in joining the wire.

[0092] (2) In addition, if a portion of the main body 41 of the retainer 40 is removed to form an exposed portion 44, the wire can be placed in the removed space, thus preventing the wire from contacting other components (e.g., the end cover 7 disposed on the second axial Da2 side of the second busbar unit 5).

[0093] (3) In the second bus bar unit 5 and the motor 1 described above, the substrate portion 51 of the bus bar 50 is covered by the holder 40, and the exposed portion 44 in which only the joint portion 52 of the substrate portion 51 is exposed to the first direction (in this case, the second axial direction Da2) of the plate thickness direction of the substrate portion 51 and the guide portion 43 that guides the wire (the start wire Ws) from the second direction (in this case, the first axial direction Da1) of the plate thickness direction toward the first direction are provided to the holder 40. Thus, the wire guided by the guide portion 43 from the second direction toward the first direction can be brought into abutment with the joint portion 52 exposed by the exposed portion 44 attached to the guide portion 43 from the first direction side, and the wire and the joint portion 52 can be joined by spot welding. Therefore, compared with the existing solder joint based on manual work, the working hours involved in the joining of the wire can be reduced.

[0094] (4) If the substrate portions 51 of the plurality of bus bars 50 provided to the second bus bar unit 5 are arranged to lie on the same plane, the portion of the holder 40 of the second bus bar unit 5 that covers the substrate portions 51, that is, the thickness of the main body portion 41 in the axial direction can be reduced. Thus, the thinness of the second bus bar unit 5 can be achieved, and further, the miniaturization of the device (in this case, the motor 1) to which the second bus bar unit 5 is applied can be facilitated.

[0095] (5) If the joint portion 52 is provided to the substrate portion 51 at a position other than the both end portions in the extension direction and the portions of the substrate portion 51 adjacent to both sides of the joint portion 52 in the extension direction are not exposed but covered by the holder 40, the joint portion 52 becomes a state of being supported at both ends, and thus the holding force of the bus bar 50 at the time of spot welding is improved, and the falling of the bus bar 50 is prevented, so that the joining of the wire with respect to the joint portion 52 can be performed more appropriately.

[0096] (6) In the motor 1 described above, the start wires Ws of the wires W of each coil 16 (each coil group 17) of the stator 3 are all led out from the second axial direction Da2 side. In addition, for the second bus bar unit 5, the holder 40 is placed on the second axial direction Da2 side of the stator 3. The guide portion 43 is provided as a through-hole through which the start wire Ws of each coil 16 (each coil group 17) passes in the axial direction, and the exposed portion 44 is provided as a notch that exposes the joint portion 52 of the substrate portion 51 to the second axial direction Da2 on the radial inner side of the through-hole 43.

[0097] With this structure, the assembly of the second bus bar unit 5 with respect to the stator 3 can be completed by simply placing the retainer 40 on the stator 3 while passing the start wire Ws through the through-hole 43, and thus the assembly man-hours can be reduced. In addition, the portions of the wire Ws of each coil 16 (each coil group 17) that are to be joined to the bus bar 50 of the second bus bar unit 5 are the start wires Ws that are not likely to deviate in position, and thus these start wires Ws can be simply passed through the through-hole 43 when the retainer 40 is placed on the stator 3, and thus the assembly man-hours can be reduced in this respect as well.

[0098] Further, since the joining portion 52 of the substrate portion 51 that is covered by the retainer 40 placed on the stator 3 is exposed to the second axial direction Da2 by the notch 44, the start wire Ws that has passed through the through-hole 43 can be joined to the joining portion 52 from the second axial direction Da2 of the stator 3 by spot welding. Thus, compared to the conventional soldering joint based on manual work, the man-hours involved in the wiring of the start wire Ws can be reduced. In addition, since the joining of the start wire Ws can be performed by spot welding without the need for soldering based on manual work, the joining process of the start wire Ws can be automated and incorporated into the manufacturing process of the motor 1.

[0099] (7) In the above-described second bus bar unit 5, the notch 44 is provided on the radially inner side of the through-hole 43. Thus, the start wire Ws that has passed through the through-hole 43 can be bent toward the radially inner side rather than the radially outer side and brought into abutment with the joining portion 52, and thus the electric leakage from the start wire Ws to the housing 6 can be prevented.

[0100] (8) If the start wires Ws of the coils 16 (coil groups 17) of different phases that are wired by the bus bars 50 of the second bus bar unit 5 are led out from the same slot 15 in a circumferentially adjacent manner, these start wires Ws can be passed through one through-hole 43 and joined to the joining portion 52 by spot welding. Thus, the assembly man-hours can be further reduced.

[0101] [3. Other]

[0102] The above-described second bus bar unit 5 and the structure of the motor 1 are examples, and are not limited to the above-described structure. For example, the motor 1 can be configured by arranging the second bus bar unit 5, the stator 3, and the first bus bar unit 4 in this order from the first axial direction Dal toward the second axial direction Da2. In this case, the "first direction" and the "predetermined axial direction" described in the technical solution become the first axial direction Dal, and the "second direction" described in the technical solution becomes the second axial direction Da2. Note that the motor 1 can not be provided with the first bus bar unit 4.

[0103] The second bus bar unit 5 can also not be an insert-molded product in which the plurality of bus bars 50 are molded with the resin-made holder 40, but can be a structure in which the plurality of bus bars 50 are assembled (fitted) inside the holder 40 after the molding of the resin-made holder 40. Likewise, the first bus bar unit 4 can also not be an insert-molded product, but can be a structure in which the plurality of bus bars 30 are assembled (fitted) inside the holder 20 after the molding of the resin-made holder 20. Note that the terminal wire Wf can also be joined to the bus bar 30 of the first bus bar unit 4 by soldering.

[0104] The winding wire W provided to the stator 3 can not form two coils 16 of the same phase arranged adjacent to each other, but can form a single coil 16, or can continuously form four coils 16 of the same phase. That is, the number of winding wires W provided to the stator 3 is not limited to the above-described six. The starting wires Ws of the winding wires W of the coils 16 of different phases formed adjacent to each other in the circumferential direction can also not be drawn out from the same slot 15. The number of coils 16 provided to the stator 3 can also not be twelve.

[0105] The bus bar 50 of the second bus bar unit 5 can not be a terminal electrically connected to an external power supply, but can be a simple bus bar (conductive body) that electrically connects the terminal electrically connected to the external power supply and each coil 16 (each coil group 17). In this case, the U-line bus bar 50u, the V-line bus bar 50v, and the W-line bus bar 50w can each extend only around the joint portion 52 in a manner not overlapping in the circumferential direction.

[0106] The substrate portion 51 as the "substrate portion" described in Technical Solution 1 can be not only a substantially arc shape, but also a shape other than a plate shape. In addition, the substrate portion 51 as the "substrate portion" described in Technical Solution 3 can be not only a plate shape, but also a shape other than a substantially arc shape. The joint portion 52 can be provided to an end portion in the extending direction of the substrate portion 51 that is a plate shape.

[0107] The holder 40 of the second bus bar unit 5 can be not only a circular ring shape, but also a shape other than a circular ring shape, as long as the shape is a shape capable of covering the substrate portion 51. The holder 40 of the second bus bar unit 5 can be, for example, a circular arc shape, a disc shape, a fan shape, or a rectangular shape, and the main body portion 41 of the holder 40 can not be a plate shape when viewed in the radial direction.

[0108] The notch 44 provided in the retainer 40 of the second busbar unit 5 may also be provided radially outside the through hole 43. Alternatively, the through hole 43 and notch 44 may not be provided relative to all the joint portions 52 of the three busbars 50 provided in the second busbar unit 5, but only relative to the joint portion 52 of one of the three busbars 50. When the two starting lines Ws connected to each busbar 50 of the second busbar unit 5 are led out at a relatively far position in the circumferential direction, a through hole 43 and notch 44 may be provided to engage each starting line Ws with the substrate portion 51. That is, the through hole 43 may not be a hole that leads out both starting lines Ws uniformly, and multiple through holes 43 and notches 44 may be provided relative to the substrate portion 51 of one busbar 50.

[0109] The exposed portion 44 need only be a portion that exposes only the joint portion 52 of the substrate portion 51, and it does not necessarily have to be a notch formed by cutting off the main body portion 41 from the first direction side (second axial direction Da2 side). The guide portion 43 does not necessarily have to be a through hole that penetrates the main body portion 41 axially. For example, the guide portion 43 may also be a notch formed by cutting off the main body portion 41 radially outward in a manner that penetrates the main body portion 41 axially.

[0110] The busbar unit equipped with guide section 43 and exposed section 44 may not be the second busbar unit 5 that connects two different phases of the three-phase coils 16 (coil groups 17), but may be the first busbar unit 4 that connects the three-phase coils 16 (each coil group 17) in the same phase. The busbar unit may also have the end wire Wf of the winding W connected to it. The busbar unit only needs to provide at least one conductor connection, and this conductor may not be the winding W of the stator 3.

[0111] When a busbar unit is provided with multiple busbars, the plate-shaped substrate portion of these busbars may also be locally repeated in the thickness direction. Alternatively, the busbar unit may not have multiple busbars.

[0112] Explanation of reference numerals in the attached figures

[0113] 1. Motor (brushless motor)

[0114] 1s axis

[0115] 2 rotors

[0116] 3. Stator

[0117] 5. Second busbar unit (busbar unit)

[0118] 15 slots

[0119] 16 coils

[0120] 16u U-phase coil (coil)

[0121] 16v V-phase coil (coil)

[0122] 16w W-phase coil (coil)

[0123] 17 coil group (coil)

[0124] 17u U-phase coil group (coil)

[0125] 17v V-phase coil group (coil)

[0126] 17w W-phase coil group (coil)

[0127] 40 retainer

[0128] 41 main body portion

[0129] 43 through hole (guide portion)

[0130] 44 notch (exposed portion)

[0131] 50 bus bar

[0132] 50u U-line bus bar (bus bar)

[0133] 50v V-line bus bar (bus bar)

[0134] 50w W-line bus bar (bus bar)

[0135] 51 substrate portion

[0136] 52 joint portion (part of substrate portion)

[0137] Da1 first axial direction (second direction)

[0138] Da2 second axial direction (first direction, prescribed axial direction)

[0139] W wire (conductive wire)

[0140] Ws starting wire (conductive wire).

Claims

1. A bus bar unit characterized by comprising: a bus bar of an electrically conductive material having a plate-shaped substrate portion; and a resin-made holding member covering the substrate portion, the bus bar unit is characterized in that: the bus bar unit has: an exposed portion exposing only a portion of the substrate portion in a first direction in a plate thickness direction of the substrate portion; and a guide portion attached to the exposed portion, guiding a wire to be joined to the portion from a second direction opposite to the first direction toward the first direction, the portion is provided at a position other than both end portions in a direction of extension of the substrate portion, a portion of the substrate portion adjacent to both sides of the portion in the direction of extension of the portion is not exposed but covered by the holding member.

2. The bus bar unit according to claim 1, characterized in that: a plurality of the bus bars are provided, the substrate portions of the plurality of the bus bars are located on the same plane.

3. The bus bar unit according to claim 1 or 2, characterized in that: the bus bar unit is applied to an inner rotor type brushless motor having a ring-shaped stator and a rotor located on an inner side in a radial direction of the stator, the wire is a start wire of a wire winding forming a coil of the stator, drawn out to a prescribed axial side in an axial direction of the stator, in a state where the first direction is along the prescribed axial direction, the holding member is placed on the prescribed axial side of the stator, the guide portion is a through-hole through which the start wire passes along the axial direction, the exposed portion is a notch exposing the portion of the substrate portion toward the prescribed axial direction on the inner side of the through-hole or an outer side in the radial direction.

4. The bus bar unit according to claim 3, characterized in that: the notch is provided on the inner side of the through-hole.

5. A brushless motor characterized by comprising: the bus bar unit according to claim 3; the stator on which the bus bar unit is placed; and the rotor rotating integrally with a shaft on the inner side of the stator.

6. The brushless motor according to claim 5, characterized in that: three-phase coils are provided in the stator, the bus bar is a terminal connecting and electrically connecting different two-phase coils among the three-phase coils to an external power supply device, and a plurality of the bus bars are provided, the holding member has the same number of the through-holes and the notches as the bus bars, the start wire of the wire winding forming each of the different two-phase coils connected by each of the bus bars is drawn out from the same slot toward the prescribed axial direction, passes through the common through-hole, and is joined to the portion of the bus bar.

7. A bus bar unit characterized by comprising: the bus bar unit is applied to an inner rotor type brushless motor having a ring-shaped stator and a rotor located on an inner side in a radial direction of the stator, the bus bar unit has: a bus bar of an electrically conductive material having a plate-shaped substrate portion; and a resin-made holding member covering the substrate portion, the holding member has: an exposed portion exposing only a portion of the substrate portion in a first direction in a plate thickness direction of the substrate portion; and a guide portion attached to the exposed portion, guiding a wire to be joined to the portion from a second direction opposite to the first direction toward the first direction, the portion is provided at a position other than both end portions in a direction of extension of the substrate portion, a portion of the substrate portion adjacent to both sides of the portion in the direction of extension of the portion is not exposed but covered by the holding member. a guide portion attached to the exposed portion, which guides a lead wire to be engaged with the portion from a second direction opposite to the first direction toward the first direction, the lead wire is a start wire of a winding forming a coil of the stator, which is drawn out to a prescribed axial side in an axial direction of the stator, in a state where the first direction is along the prescribed axial direction, the holding member is placed on the prescribed axial side of the stator, the guide portion is a through-hole through which the start wire passes along the axial direction, the exposed portion is a notch which exposes the portion of the substrate portion to the prescribed axial direction on the inner side of the through-hole or the outer side in the radial direction, the notch is provided on the inner side of the through-hole.

8. The bus bar unit according to claim 7, wherein a plurality of the bus bars are provided, the substrate portions of the plurality of bus bars are located on the same plane.

9. A brushless motor, comprising: the bus bar unit according to claim 7; the stator on which the bus bar unit is placed; and the rotor which rotates integrally with a shaft on the inner side of the stator.

10. The brushless motor according to claim 9, wherein three-phase coils are provided in the stator, the bus bars are terminals which connect and electrically connect different two-phase coils among the three-phase coils to an external power supply device, and a plurality of the bus bars are provided, the holding member has the same number of the through-holes and the notches as the bus bars, the start wire of the winding forming each of the different two-phase coils to which each of the bus bars is connected is drawn out from the same slot to the prescribed axial direction, passes through the common through-hole, and is engaged with the portion of the bus bar.

11. A brushless motor which is an inner rotor type brushless motor, comprising: the bus bar unit according to claim 7; the stator on which the bus bar unit is placed; and the rotor which is located on the inner side in the radial direction of the stator and rotates integrally with a shaft on the inner side of the stator, the bus bar unit according to claim 7, the bus bar unit according to claim 7, the holding member according to claim 7, the exposed portion according to claim 7, the guide portion according to claim 7, the start wire according to claim 7, in a state where the first direction is along the prescribed axial direction, the holding member according to claim 7, the guide portion according to claim 7, the exposed portion according to claim 7, three-phase coils are provided in the stator, ​ ​ ​ ​ The bus bars are terminals for connecting different two-phase coils of the three-phase coils to an external power supply and are provided with a plurality of The holding member has the same number of through holes and notches as the bus bars, The beginning of the winding of each of the different two-phase coils to which each bus bar is connected is drawn from the same slot in the prescribed axial direction, passes through the common through hole, and is engaged with the portion of the bus bar.

12. The brushless motor according to claim 11, wherein The substrate portions of the plurality of bus bars are located on the same plane.

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