Motor

Abstract

To provide a motor of which the length in an axial direction is short by devising the arrangement of a neutral point bus bar.SOLUTION: A motor comprises a plurality of coils wound around a stator and a neutral point bus bar mutually connecting the plurality of coils. A lead wire of each of the plurality of coils is bent in a radial direction from an axial direction of the stator. The neutral point bus bar is connected to portions of a plurality of lead wires extending in the radial direction. In the motor, the lead wire is bent in the radial direction, and the neutral point bus bar is connected to the portion extending in the radial direction. Therefore, the neutral point bus bar is positioned closer to a center of the stator than ends of the coils in the axial direction of the stator. In such a structure, a length of the motor in the axial direction can be shortened.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The technology disclosed in this specification relates to a motor.

Background Art

[0002] In a three-phase AC motor, one end of each of the three coils of the U-phase / V-phase / W-phase is connected to each other at the neutral point. One end of the three coils is connected by a metal piece called a bus bar (Patent Documents 1-3). Hereinafter, the three-phase AC motor will be simply referred to as a "motor", and the bus bar that connects one end of the three coils to each other will be referred to as a "neutral point bus bar". In any of the motors disclosed in Patent Documents 1-3, the neutral point bus bar is arranged outside the coil in the axial direction of the motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the neutral point bus bar is arranged outside the coil in the axial direction, the axial length of the motor becomes long. This specification devises the arrangement of the neutral point bus bar and provides a motor capable of making the axial length shorter than before.

Means for Solving the Problems

[0005] The motor disclosed in this specification includes a plurality of coils wound around a stator and a neutral point busbar that interconnects the plurality of coils. The lead wire of each of the plurality of coils is bent from the axial direction of the stator to the radial direction. The neutral point busbar is connected to a portion that extends in the radial direction of the plurality of lead wires. The motor disclosed in this specification bends the lead wires in the radial direction and connects the neutral point busbar to the portion extending in the radial direction. Therefore, the entire neutral point busbar can be brought closer to the center of the stator. With this structure, the axial length of the motor can be shortened.

[0006] The details and further improvements of the technology disclosed in this specification will be described in the following "Mode for Carrying Out the Invention".

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0008] The motor 2 of the embodiment will be described with reference to the drawings. FIG. 1 shows a plan view of the motor 2 seen from its axial direction. In FIG. 1, the state where the cover of the motor 2 is removed is depicted. FIG. 2 is a perspective view of the range of the broken-line rectangle II in FIG. 1. However, in FIG. 2, the neutral point busbar 10 is drawn as a virtual line. In FIGS. 1 and 2, the illustration of the rotor is omitted. FIG. 3 shows a perspective view of the neutral point busbar 10. FIG. 4 shows a view of the motor 2 seen from the direction of arrow IV in FIG. 1, and FIG. 5 shows a view of the motor 2 seen from the direction of arrow V in FIG. 1.

[0009] The motor 2 includes a stator 4. The stator 4 is housed in a housing 3. The motor 2 is an 8-pole 12-slot three-phase AC motor. The stator 4 is provided with 12 teeth 5, and coils 6 are wound around each of the teeth 5. Three-phase alternating current with a 120-degree phase difference flows through each of the adjacent three coils 6u, 6v, and 6w. The motor 2 includes 4 sets of coil sets of coils 6u, 6v, and 6w. In each coil set, alternating current with a 120-degree phase difference flows through the adjacent three coils.

[0010] The three coils 6u, 6v, and 6w are star-connected. Star connection means a structure in which one ends of the three coils 6u, 6v, and 6w are connected to each other. The connection point of the three coils 6u, 6v, and 6w is called the neutral point. The lead wires 7u, 7v, and 7w of the coils 6u, 6v, and 6w are connected to each other by a neutral point bus bar 10. As shown in FIG. 1, the motor 2 includes 4 neutral point bus bars 10, and each neutral point bus bar 10 connects the adjacent three coils 6u, 6v, and 6w.

[0011] The neutral point bus bar 10 is an elongated metal plate, and a U-shaped portion 10a is provided generally in the center and L-shaped portions 10b are provided at both ends. The U-shaped portion 10a and the L-shaped portions 10b are bent portions obtained by bending the neutral point bus bar 10. Among the lead wires 7u, 7v, and 7w of the three coils 6u, 6v, and 6w, the lead wire 7v located in the center is fitted into the U-shaped portion 10a of the neutral point bus bar 10. At this time, since the U-shaped portion 10a can position the neutral point bus bar 10, it is possible to eliminate the need for a clamp used when welding the lead wires 7u, 7v, and 7w and the neutral point bus bar 10. The L-shaped portions 10b of the neutral point bus bar 10 are in contact with the lead wires 7u and 7w on both sides among the three lead wires. Each of the three lead wires 7u, 7v, and 7w is welded to the neutral point bus bar 10, and the three coils 6u, 6v, and 6w are electrically connected to each other via the neutral point bus bar 10.

[0012] The lead wires 7u, 7v, and 7w are located at one end of the motor 2 (stator 4) in the axial direction. Also, the lead wires 7u, 7v, and 7w are located inside the coil 6 in the radial direction of the stator 4. The lead wires 7u, 7v, and 7w extend along the axial direction of the stator 4, and their tips are bent in the radial direction of the stator 4. The tips of the lead wires 7u, 7v, and 7w are referred to as tips 7ue, 7ve, and 7we, respectively (see Fig. 5). Note that the "tip" means the part extending in the radial direction of each lead wire. The tips 7ue, 7ve, and 7we extend along the radial direction of the stator 4, and the neutral point bus bar 10 is fixed to these tips 7ue, 7ve, and 7we.

[0013] In Fig. 4, the symbol E indicates the end of the coil 6u in the stator axial direction. The tip 7ue of the lead wire 7u is located closer to the center in the axial direction of the stator 4 than the end E of the coil 6u. The same applies to the lead wires 7v and 7w of the coils 6v and 6w. The neutral point bus bar 10 connected to the tips 7ue, 7ve, and 7we is also located closer to the center in the axial direction of the stator 4 than the end E of the coil 6. Since the structure of the motor 2 is such that the neutral point bus bar 10 is not located outside the coil 6 in the axial direction (farther from the stator center than the coil 6), the axial length of the motor 2 can be shortened.

[0014] In the neutral point bus bar 10, the extension part 10c connects the U-shaped part 10a and the L-shaped part 10b. The extension part 10c is located between the tip 7ve of the central lead wire 7v and the tips 7ue (7we) of the end lead wires 7u (7w). With this structure, the extension part 10c serves to keep the distance between the tip 7ve and the end tips 7ue (7we) constant.

[0015] Some of the features of the motor 2 are listed below. The motor 2 includes a plurality of coils 6u, 6v, 6w wound around the stator 4 and a neutral point bus bar 10 that connects the plurality of coils to each other. The lead wires 7u, 7v, 7w of the plurality of coils are located at one end in the stator axis direction. Each of the lead wires 7u, 7v, 7w is bent from the stator axis direction to the radial direction. The neutral point bus bar 10 is connected to the portions (tips 7ue, 7ve, 7we) of the plurality of lead wires 7u, 7v, 7w that extend in the stator radial direction. With this structure, the axial length of the motor 2 can be shortened.

[0016] The neutral point bus bar 10 is located closer to the center of the stator 4 than the end E of the coil 6 in the stator axis direction. The neutral point bus bar 10 includes a U-shaped portion 10a that surrounds three sides of the lead wire 7v. Note that the U-shaped portion may be changed to a V-shaped portion that surrounds two sides of the lead wire 7v. L-shaped portions 10b are provided at both ends of the neutral point bus bar 10, and the lead wires 7u, 7w are in contact with the respective L-shaped portions 10b. The L-shaped portion 10b may be changed to a U-shaped portion that surrounds three sides of the lead wire 7u (7w), or may be changed to an I-shaped portion that is in contact with a part of the lead wire 7u (7w).

[0017] Points to note regarding the technology described in the embodiment are described. The neutral point bus bar 10 is located closer to the center of the motor than the end E of the coil 6 in the axial direction. In other words, the neutral point bus bar 10 is located between the two ends of the coil 6 in the axial direction.

[0018] The motor 2 of the embodiment includes a stator 4 with 12 slots (12 coils). The technology disclosed in this specification can also be applied to stators with 3 slots, 6 slots, etc.

[0019] In the figure, only the lead wires 7u, 7v, 7w at one end of the coils 6u, 6v, 6w are drawn, and the lead wires at the other end are not shown. The other lead wires of the coils 6u, 6v, 6w are connected to the inverter by another bus bar not shown.

[0020] The neutral busbar 10 is made of a metal plate. The neutral busbar 10 may also be made of a metal bar. The lead wires 7u, 7v, and 7w of the three coils 6u, 6v, and 6w are located inside the coil 6 in the radial direction of the stator 4. The lead wires 7u, 7v, and 7w extend along the axial direction of the stator 4, and their tips 7ue, 7ve, and 7we are bent in the radial direction of the stator 4. The tips 7ue, 7ve, and 7we of the lead wires 7u, 7v, and 7w extend toward the center of the stator 4. The lead wires 7u, 7v, and 7w may be located outside the coil 6 in the radial direction of the stator 4. In that case, the tips 7ue, 7ve, and 7we extend outward along the radial direction of the stator 4. And the neutral busbar 10 is arranged outside the coil 6 in the stator radial direction.

[0021] The neutral busbar 10 may be fixed to the stator 4 via an insulator. Alternatively, the neutral busbar 10 may be fixed to the housing 3 via an insulator.

[0022] As described above, specific examples of the present invention have been described in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or the drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Also, the technology illustrated in this specification or the drawings can achieve multiple purposes simultaneously, and achieving one of those purposes itself has technical utility.

Explanation of Reference Numerals

[0023] 2: Motor 3: Housing 4: Stator 5: Teeth 6, 6u, 6v, 6w: Coils 7u, 7v, 7w: Lead Wires 7ue, 7ve, 7we: Tips 10: Neutral Busbar 10a: U-shaped Portion 10b: L-shaped Portion 10c: Extension Portion

Claims

1. a plurality of coils wound around a stator; a neutral point busbar connecting the plurality of coils to each other; and comprising; the lead wire of each of the plurality of coils is bent from the axial direction of the stator to the radial direction; the neutral point busbar is connected to a portion of the plurality of lead wires extending in the radial direction, a motor.

2. The motor according to claim 1, wherein the neutral point busbar is located closer to the center of the stator than the end of the coil in the axial direction.

3. The motor according to claim 1 or 2, wherein the neutral point busbar includes at least one U-shaped portion surrounding three sides of the lead wire or at least one V-shaped portion surrounding two sides of the lead wire.

4. The motor according to claim 3, wherein the U-shaped portion or the V-shaped portion is a bent portion obtained by bending the neutral point busbar.

5. The motor according to claim 1, wherein the neutral point busbar is connected only to the plurality of lead wires.

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