Electric drive source

Abstract

The present invention provides an electric drive source that achieves a reduction in manufacturing costs and the number of assembly steps and a decrease in the size of the drive source. An electric drive source (1) comprises: a motor case part (10) that covers a stator (4) of a motor (6); an inverter case part (11) that covers a substrate (7) of an inverter (8); a speed reducer case part (12) that is provided between the motor case part (10) and the inverter case part (11) and that covers a speed reducer (9); and a lead wire (15) that connects a motor-side terminal (13) and an inverter-side terminal (14). The lead wire (15) is disposed inside the speed reducer case part (12) and along the direction in which the motor case part (10), the speed reducer case part (12), and the inverter case part (11) are arranged.

Description

Electric drive source

[0001] The present invention relates to an electric drive source mounted on a vehicle.

[0002] Conventionally, there has been known an electric drive source in which three components are arranged side by side in the vehicle width direction on the frame of a saddle-type electric vehicle: a motor, a gear mechanism that transmits the rotational force of the motor to an output shaft, and an inverter that supplies drive current to the motor (see, for example, Patent Document 1).

[0003] In the electric drive source of Patent Document 1, a gear mechanism is disposed between the motor and the inverter, which makes it difficult for the motor and the inverter, which become hot, to thermally affect each other, thereby improving durability. In addition, heat from the motor and the inverter is dissipated to a gear case that covers the gear mechanism, which is relatively cool, so the electric drive source has good cooling properties.

[0004] Patent No. 7239682

[0005] Patent Document 1 does not disclose the wiring between the motor and inverter in the electric drive source. Since the motor and inverter are separated from each other, the most common method of wiring between them is to take one end of a lead wire connected to the motor and the other end of the lead wire outside the motor case, then lead the other end of the lead wire into the inverter case and connect the other end of the lead wire to the inverter board.

[0006] However, this wiring method requires the provision of a seal to seal the gap between the lead wires extending outside each case and the case itself. Furthermore, since the lead wires must be routed between the inside and outside of each case, the workability is poor and the manufacturing costs of the electric drive source increase. Furthermore, the presence of lead wires and a seal outside each case increases the size of the electric drive source.

[0007] In view of the problems of the prior art, an object of the present invention is to reduce the manufacturing cost and assembly steps of an electric drive source and to reduce the size of the drive source.

[0008] The electric drive source of the present invention is an electric drive source mounted on a vehicle, and includes a motor having an output shaft, a rotor, a stator facing the rotor, and a coil provided on the stator, an inverter having a board that outputs a drive current to be supplied to the coil, and a reducer that decelerates the rotation of the rotor and transmits it to the output shaft.

[0009] The electric drive source also includes a motor case portion that covers the stator, an inverter case portion that covers the circuit board, a reducer case portion that is provided between the motor case portion and the inverter case portion and covers the reducer, motor side terminals that are arranged within the motor case portion and to which ends of the coil are connected, inverter side terminals that are arranged on the circuit board and output the drive current, and connection means that connect the motor side terminals and the inverter side terminals.

[0010] The connection means is disposed inside the reducer case along the direction in which the motor case, the reducer case, and the inverter case are arranged.

[0011] According to the present invention, the connecting means connects the motor side terminal and the inverter side terminal over the shortest distance through the reducer case portion, thereby providing an electric drive source that requires fewer assembly steps, is inexpensive, and is compact.

[0012] Fig. 2 is a cross-sectional view of an electric drive source according to an embodiment of the present invention. Fig. 3 is a cross-sectional view showing a portion where an inverter board is fixed in the electric drive source of Fig. 1. Fig. 4 is a cross-sectional view showing an enlarged view of the vicinity of lead wires (connection means) in the cross-sectional view of Fig. 1. Fig. 5 is a perspective view showing a portion where connection means side terminals and motor side terminals are connected in the electric drive source of Fig. 1.

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 shows a cross section of an electric drive source according to an embodiment of the present invention. This electric drive source 1 is mounted on the frame of a vehicle such as a straddle-type electric vehicle and provides driving force to the vehicle.

[0014] 1, the electric drive source 1 includes an output shaft 2 that outputs a driving force, a motor 6 that has a rotor 3, a stator 4 facing the rotor 3, and a coil 5 provided on the stator 4, an inverter 8 that has a board 7 that outputs a driving current to be supplied to the coil 5, and a reducer 9 that reduces the rotation of the rotor 3 and transmits it to the output shaft 2. The stator 4 generates a rotating magnetic field based on the driving current supplied to the coil 5, causing the rotor 3 to rotate.

[0015] The stator 4 is housed together with the rotor 3 in a motor case 10. The circuit board 7 of the inverter 8 is housed in an inverter case 11. A reducer case 12 that houses a reducer 9 is provided between the motor case 10 and the inverter case 11. The reducer 9 is configured, for example, using a small gear provided on the rotor 3 and a large gear fixed to the output shaft 2 so as to mesh with the small gear.

[0016] Motor-side terminals 13, to which the ends of the coils 5 are connected, are disposed within the motor case 10. Inverter-side terminals 14, which output a drive current to the motor 6, are provided on the circuit board 7 of the inverter 8. The motor-side terminals 13 and the inverter-side terminals 14 are connected by a connecting means. In this embodiment, lead wires 15 are used as the connecting means.

[0017] The lead wires (connecting means) 15 are arranged inside the reducer case 12 along the arrangement direction D of the motor case 10, the reducer case 12, and the inverter case 11. In this embodiment, the electric drive source 1 is mounted on the vehicle in the positional relationship shown in Fig. 1 relative to the front F, rear B, left L, and right R of the vehicle. Therefore, the arrangement direction D coincides with the width direction of the vehicle.

[0018] The motor case portion 10 includes a reducer-side motor case portion 16 that covers the reducer 9 side of the motor 6 in the arrangement direction D. The inverter case portion 11 includes a reducer-side inverter case portion 17 that covers the reducer 9 side of the inverter 8 in the arrangement direction D. The reducer case portion 12 is composed of the reducer-side motor case portion 16 and the reducer-side inverter case portion 17.

[0019] 2 shows a portion of the inverter 8 of the electric drive source 1 where the circuit boards 7 (7a, 7b) are fixed. As shown in FIG. 2, the inverter case 11 includes an outer inverter case 11a that covers the outside of the inverter 8 in the arrangement direction D (see FIG. 1). The circuit board 7 of the inverter 8 includes a circuit board 7a on which switching elements are arranged and a circuit board 7b on which control system elements are arranged. The circuit boards 7a and 7b are fixed to the outer inverter case 11a with bolts 18a and 18b, respectively.

[0020] Figure 3 is an enlarged view of the lead wire 15 and its vicinity in the cross section of Figure 1. As shown in Figure 3, the lead wire 15 has a connection means-side terminal 19 at the end on the motor 6 side. The connection means-side terminal 19 is provided with a connection means-side terminal hole 20. The motor-side terminal 13 connected to the coil 5 is provided with a motor-side terminal hole 21.

[0021] 4 shows a portion of the reducer-side motor case 16 where the connection means-side terminals 19 of the lead wires (connection means) 15 are connected to the motor-side terminals 13 of the motor 6. In FIG. 4, this portion is shown with the inverter 8 and inverter case 11 removed.

[0022] As shown in Fig. 4, a bolt 18c is passed through the connection means-side terminal hole 20 (see Fig. 3) of the connection means-side terminal 19 and the motor-side terminal hole 21 (see Fig. 3) of the motor-side terminal 13. The bolt 18c is threaded into a threaded hole of a nut 22, connecting the connection means-side terminal 19 and the motor-side terminal 13 in close contact with each other.

[0023] A bolt insertion hole 23 is provided in the side wall of the reducer-side motor case section 16 of the motor case section 10 (see FIG. 3 ), into which the bolt 18c is inserted when connecting the connection means-side terminal 19 and the motor-side terminal 13. A plug is provided to close the bolt insertion hole 23. For example, a bolt plug 24 that screws into the bolt insertion hole 23 is used as the plug.

[0024] In this configuration, when assembling the electric drive source 1 while connecting the inverter 8 connection means side terminals 19 and the motor side terminals 13 of the motor 6, the motor case 10 is prepared, in which the motor 6 components such as the rotor 3, stator 4, and motor side terminals 13 are assembled and covered with the reducer side motor case 16. In addition, the circuit boards 7a and 7b are fixed, and an outer inverter case 11a is prepared, in which the lead wires 15 are connected to the circuit board 7a.

[0025] Next, the reducer 9 having the output shaft 9 is placed in the reducer-side motor case 16. Then, the reducer-side inverter case 17 is attached to the reducer-side motor case 16 to form the reducer case 12. As a result, the reducer 9 is housed in the rear B side portion of the reducer case 12.

[0026] Next, the outer inverter case part 11a prepared as described above is attached to the reducer-side inverter case part 17. This attachment is performed so that the lead wires 15 extending from the outer inverter case part 11a pass through the reducer-side inverter case part 17.

[0027] During this attachment, the connection means side terminal 19 of the lead wire 15 is positioned over the motor side terminal 13 in the reducer side motor case portion 16, and the connection means side terminal hole 20 is aligned with the motor side terminal hole 21. This positioning is easily achieved because the lead wire 15 has elasticity that allows it to maintain its shape.

[0028] Next, the bolt 18c is inserted from the bolt insertion hole 23 of the reducer-side motor case portion 16, passed through the connection means-side terminal hole 20 and the motor-side terminal hole 21, and further screwed onto the nut 22 arranged on the motor-side terminal 13. As a result, the connection means-side terminal hole 20 and the motor-side terminal hole 21 are fastened together by the bolt 18c and the nut 22, and a connected state is established.

[0029] Next, the bolt plugs 24 are screwed into the bolt insertion holes 23, and the bolt insertion holes 23 are closed by the bolt plugs 24. This prevents dust and other particles from entering the interior of the electric drive source 1. This completes the assembly of the electric drive source 1, with the lead wires 15 connecting the connection means side terminals 19 and the motor side terminals 13 disposed inside the reducer case 12.

[0030] As described above, in the electric drive source 1 of this embodiment, the motor side terminal 13 of the motor 6 and the inverter side terminal 14 of the inverter 8 are connected by the lead wire (connection means) 15 arranged inside the reducer case portion 12.

[0031] This eliminates the need to take the time and effort of leading the lead wires 15 outside the case parts of the electric drive source 1 and to use a sealant to seal between the led out lead wires 15 and each case part, and allows the motor side terminals 13 and the inverter side terminals 14 to be connected with the shortest lead wires 15. Furthermore, because the lead wires 15 fit within each case part, the electric drive source 1 can be made smaller.

[0032] That is, according to the electric drive source 1 of this embodiment, it is possible to improve the workability during assembly, reduce manufacturing costs, and save space (size) around the electric drive source 1 .

[0033] Furthermore, since the motor case 10, the reducer case 12, and the inverter case 11 are arranged in the direction parallel to the width direction of the vehicle, the electric drive source 1 can be arranged compactly relative to the vehicle body.

[0034] Furthermore, the reducer-side motor case 16 shares the reducer case 12, and the reducer-side inverter case 17 shares the reducer case 12. The reducer case 12 is then made up of the reducer-side motor case 16 and the reducer-side inverter case 17. This allows the number of components of the electric drive source 1 to be reduced, leading to cost reduction and a more compact device.

[0035] In addition, the board 7 (7a, 7b), which becomes very hot, is fixed to the outer inverter case part 11a, which is exposed to the outside air, and the heat from the board 7 is dissipated through the outer inverter case part 11a, thereby improving the cooling performance of the electric drive source 1.

[0036] Furthermore, after inserting a bolt 18c through the bolt insertion hole 23 in the side wall of the reducer side motor case portion 16 and connecting the connection means side terminal 19 of the lead wire (connection means) 15 to the motor side terminal 13 of the motor 6 with the bolt 18c, the bolt insertion hole 23 is closed with a bolt plug 24, so that the lead wire (connection means) 15 can be easily and reliably connected to the motor side terminal 13 even after the motor case portion 10 and the reducer case portion 12 are joined.

[0037] Although the embodiment of the present invention has been described above, the present invention is not limited to this. For example, a bus bar or the like may be used as a connecting means for connecting the inverter side terminal 14 and the motor side terminal 13.

[0038] 1...electric drive source, 2...output shaft, 3...rotor, 4...stator, 5...coil, 6...motor, 7 (7a, 7b)...circuit board, 8...inverter, 9...reduction gear, 10...motor case portion, 11...inverter case portion, 11a...outer inverter case portion, 12...reduction gear case portion, 13...motor side terminal, 14...inverter side terminal, 15...lead wire, 16...reduction gear side motor case portion, 17...reduction gear side inverter case portion, 18a, 18b, 18c...bolt, 19...connection means side terminal, 20...connection means side terminal hole, 21...motor side terminal hole, 22...nut, 23...bolt insertion hole, 24...bolt plug

Claims

1. An electric drive source to be mounted on a vehicle, comprising: an output shaft, a motor having a rotor, a stator facing the rotor, and a coil provided on the stator; an inverter having a board that outputs a drive current to be supplied to the coil; a reducer that decelerates the rotation of the rotor and transmits it to the output shaft; a motor case section that covers the stator; an inverter case section that covers the board; a reducer case section that is provided between the motor case section and the inverter case section and covers the reducer; motor-side terminals that are located within the motor case section and to which ends of the coil are connected; inverter-side terminals that are located on the board and output the drive current; and connecting means that connect the motor-side terminals and the inverter-side terminals, wherein the connecting means are located within the reducer case section along the arrangement direction of the motor case section, the reducer case section, and the inverter case section.

2. The electric drive source according to claim 1, wherein the arrangement direction is a direction along the width direction of the vehicle.

3. The electric drive source described in claim 1, characterized in that the motor case portion comprises a reducer-side motor case portion that covers the reducer side of the motor, the inverter case portion comprises a reducer-side inverter case portion that covers the reducer side of the inverter, and the reducer case portion is composed of the reducer-side motor case portion and the reducer-side inverter case portion.

4. An electric drive source as described in claim 1, characterized in that the inverter case portion has an outer inverter case portion that covers the outer side of the inverter in the arrangement direction, and the circuit board is fixed to the outer inverter case portion.

5. The electric drive source according to claim 1, wherein the connecting means comprises a connecting means-side terminal at an end on the motor side, the connecting means-side terminal having a connecting means-side terminal hole, the motor-side terminal having a motor-side terminal hole, bolts are disposed in the connecting means-side terminal hole and the motor-side terminal hole, and are passed through the connecting means-side terminal hole and the motor-side terminal hole and threaded into screw holes to connect the connecting means-side terminal and the motor-side terminal, the side wall of the motor case portion has a bolt insertion hole for inserting the bolt that connects the connecting means-side terminal and the motor-side terminal, and the bolt insertion hole is provided with a plug for closing it.