WO2020066960A1

WO2020066960A1 - Motor structure

Info

Publication number: WO2020066960A1
Application number: PCT/JP2019/037164
Authority: WO
Inventors: 由幸小林
Original assignee: 本田技研工業株式会社
Priority date: 2018-09-28
Filing date: 2019-09-24
Publication date: 2020-04-02
Also published as: CN112771768A; JP2020058087A; JP7156892B2

Abstract

Provided is an outer rotor motor in which a power control unit (PCU) 10 is attached to a heat sink plate 26 fixed to a stator that does not rotate. The heat sink plate 26 is provided with fins, and an oppossing motor case 29 is also provided with fins on an inner surface and a side surface thereof. The case 29 rotates together with the rotor and generates an air flow inside the motor, causing the heat of the heat sink plate to be transmitted to the case and diffused to the outside.

Description

Motor structure

The present invention relates to a vehicle driven by, for example, an electric motor, and particularly to a motor structure.

構成 In order to make an electric vehicle compact, it is effective to use an electric motor that is a drive source as an in-wheel motor. There has been proposed a configuration in which heat generated by an in-wheel motor is radiated to the outside via a heat pipe (see Patent Document 1 and the like).

Patent No. 5169280

In order to make the configuration of the in-wheel motor more compact, there is a configuration in which the motor is integrated with a power control unit (PCU). When the PCU is integrated with the motor, the in-wheel motor has a structure that can be housed inside the wheel. Therefore, it is desirable to provide the PCU inside the motor from the viewpoint of circuit protection. In such a configuration, it is necessary to radiate not only the heat from the PCU but also the motor. Therefore, in the above-described conventional technology, the heat pipe must be made thicker accordingly. However, in the prior art, the heat pipe is provided through the shaft of the wheel, and the thickness is limited.

The present invention has been made in view of the above conventional example, and has as its object to provide a motor structure that can efficiently cool a motor having a built-in power control unit.

In order to achieve the above object, the present invention has the following configuration. That is, according to one aspect of the present invention, the structure of the motor (11) includes:
A stator (24);
A rotor (23) rotated by a magnetic force from the stator (24);
A case (21, 29) of the motor connected to the rotor (23);
A power control unit (10) disposed inside the case (21, 29) for driving the stator (24);
A structure of a motor is provided, wherein cooling fins (111) are provided in the cases (21, 29).

According to the present invention, a motor incorporating a power control unit can be efficiently cooled.

It is a figure showing appearance and a motorcycle of an embodiment. It is a block diagram of a drive control circuit of a motor. It is an exploded perspective view of the in-wheel motor of an embodiment. It is sectional drawing of the in-wheel motor of embodiment. It is a figure showing arrangement of a circuit board in an in-wheel motor of an embodiment. It is a figure showing arrangement of a circuit board in an in-wheel motor of an embodiment. It is a figure showing arrangement of a circuit board in an in-wheel motor of an embodiment. It is a figure showing the cooling principle at the time of driving of the in-wheel motor of an embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. The following embodiments do not limit the invention according to the claims, and not all combinations of the features described in the embodiments are necessarily essential to the invention. Two or more features of the plurality of features described in the embodiments may be arbitrarily combined. In addition, the same or similar components are denoted by the same reference numerals, and redundant description will be omitted.
[First embodiment]
[Structure of Saddle Ride Type Vehicle] FIG. 1A shows an example of an appearance of a powered motorcycle 1 which is a saddle type vehicle according to the present embodiment. The motorcycle 1 has an in-wheel motor (hereinafter, may be simply referred to as a motor) 11 as a drive source, and tires 12 are mounted around the in-wheel motor 11 as a hub. The in-wheel motor 11 is rotatably supported by the swing arm 13 with its rotating shaft 112, and can directly rotate the drive wheels without the intervention of a speed reduction mechanism or a transmission mechanism. Cooling fins 111 are provided on both side surfaces of the in-wheel motor 11, and an air flow is generated on the surface by the rotation to efficiently radiate heat propagated from the inside. Power is supplied to the in-wheel motor 11 from a power control unit (or power control circuit, PCU) 10 (see FIG. 1B), and the number of rotations is controlled by the driver operating an accelerator provided on the grip of the steering wheel. Is controlled by

FIG. 1B is a block diagram of a control circuit for controlling the drive of the in-wheel motor 11. The in-wheel motor 11 of this embodiment is an outer rotor type surface magnet synchronous motor (SPMSM) structurally, and may be referred to as a brushless DC motor including the PCU 10. The in-wheel motor 11 is driven by a three-phase AC power supplied from the PCU 10. Each phase of the AC power supply may be a sine wave or a rectangular wave. The PCU 10 is driven by a low-voltage power supply (for example, a 12-V power supply) 104 and includes a controller 101 and an inverter 102. The output signal (Hall sensor signal) of the Hall sensor for detecting the rotation position of the rotor from the motor 103 is input to the controller 101. Note that the motor 103 indicates a portion where the PCU is excluded from the in-wheel motor 11. The controller 101 inputs a control signal for performing control such as switching of a current from a high-voltage power supply (HV battery) 105 to the inverter 102 based on the input Hall sensor signal. The controller 101 further adjusts the timing of a control signal to the inverter 102 to control the output frequency of the inverter 102 according to the signal indicating the accelerator opening. Further, the configuration may be such that not only the frequency but also the current can be controlled.

(4) The inverter 102 converts the high-voltage power supply 105 into three-phase AC U, V, W according to a control signal from the controller 101 and inputs the three-phase AC to the motor 103. The motor 103 is driven in synchronization with the frequency of the input power supply. The motor 103 includes a temperature sensor and a Hall sensor. A temperature signal indicating a temperature detected by the temperature sensor and a Hall sensor signal indicating a magnetic field detected by the Hall sensor are input to the controller 101. The Hall sensor signal detects the electric rotational position of the rotor by detecting the magnetic field of a permanent magnet attached to the rotor surface so that S poles and N poles are alternately arranged.

Here, in the present embodiment, the PCU 10 is incorporated inside the in-wheel motor 11 as described later. By using the in-wheel motor 11 configured as described above, the drive wheels of the motorcycle 1 are rotated, and the motorcycle 1 can travel as intended by the driver.

FIG. 2A is an exploded perspective view of the in-wheel motor 11. The main components of the in-wheel motor 11 are housed in a housing composed of a wheel case 21 and a wheel case 29 formed of metal or the like. The wheel case 21 is provided with a hole through which the shaft 112 is provided in a rotation shaft portion thereof, and has a disk shape with a peripheral portion protruding. Further, fins 111 for heat radiation are provided on the outer and inner surfaces. In this example, the fins 111 are a plurality of elongated protrusions parallel to each other, and are formed integrally with the wheel case 21. The height and the number may be determined according to the amount of heat generated in order to release the heat generated inside the in-wheel motor 11. The wheel case 29 has the same configuration as the wheel case 21, but in this example, there is no overhang of the peripheral portion provided on the outer peripheral portion. However, a configuration similar to that of the wheel case 21 may be adopted. The wheel case 21 and the wheel case 29 are fixed to each other with, for example, bolts or the like to form a case of the in-wheel motor 11, and are attached to the shaft 112 via

bearings

22 and 28. For this reason, the

wheel cases

21 and 29 can rotate with respect to the shaft 112 which is fixed to the swing arm 13 and does not rotate, and the tire 12 is attached to the outer periphery thereof, and also serves as a hub for driving wheels.

ロータ The rotor 23 is connected or fixed along the inside of the overhang of the peripheral portion of the wheel case 21. The rotor 23 is configured by arranging a plurality of permanent magnets, for example, 16 or 32, while alternately reversing the polarity. This is similar to a general outer rotor type motor. On the other hand, the circuit case 26 is fixed to the shaft 112. The circuit case 26 is, for example, a metal disk-shaped member centered on the shaft 112. A part of the surface of the circuit case 26 facing the wheel case 29 is provided with a radiating fin preferably formed integrally with the circuit case 26. A Hall element substrate 27 provided with a Hall sensor is attached to a part of the same surface. A PCU board 25 provided with the PCU 10 is attached to the surface of the circuit case 26 opposite to the Hall element board 27. The PCU board 25 and the Hall element board 27 are connected by necessary signal lines and power lines through through holes formed in the circuit case 26. Although the fin is not provided on the surface of the circuit case 26 on the PCU board 25 side in this example, it may be provided.

The stator 24 is attached to the circuit case 26 so as to surround the periphery thereof. That is, the stator 24 is fixed to the shaft 112 via the circuit case 26. Stator 24 includes windings respectively connected to three-phase AC power supply UVW from inverter 102. The stator 24 is fixed to the shaft 112, and the rotor 23 outside the stator 24 rotates.

FIG. 2B is a sectional view showing a section parallel to the rotation axis of the in-wheel motor 11. The rotor 23, the stator 24, the substrate case 26, and the like are housed in a housing formed by the

wheel cases

21 and 29 around the shaft 112 as an axis. Here, the board case 26 is a heat conductive member having high heat conductivity such as a metal, and is a member for attaching boards and the like, and also functions as a heat radiating plate. Therefore, the PCU board 25 may be attached to the board case 26 such that the heat-generating components attached thereto come into contact with the board case 26 directly or via a heat conductive material having a high thermal conductivity. Further, the stator 24 also contacts the board case 26, and the heat is transmitted to the board case 26. As a result of such a configuration, heat of the stator 24 and the PCU board 25 is easily transmitted to the board case 26. The surface of the board case 26 on which the fins are provided is opposed to the wheel case 29, and the rotation of the wheel case 29 generates an air flow in the space between the board case 26 and the wheel case 29. This air flow contacts and effectively cools the fins of the substrate case 26. Conversely, although the Hall element substrate 27 is attached to the substrate case 26, it is desirable that the Hall element substrate 27 be attached so that heat from the substrate case 26 is not easily transmitted to the Hall element.

Fig. 4 shows the situation. FIG. 4 shows the substrate case 26 and the wheel case 29 in the cross section of FIG. The rotation of the wheel case 29 generates an airflow toward the outer peripheral side along the wheel case 29, and the airflow hits the outer edge of the wheel case 21 and goes to the space on the substrate case 26 side. The air flow is directed toward the shaft 112 by the substrate case 26, and collides with the air flow generated on the opposite side across the shaft 112, thereby causing vortex convection as shown by an arrow in FIG. Due to the flow of air, heat generated in the PCU board 25, the Hall element board 27, the stator 24, and the like and transmitted to the board case 26 is further transmitted to the wheel case 29. Then, heat is effectively dissipated from the fins provided on the outer surface of the wheel case 29. The wheel case 21 also has such an effect, and the heat generated inside can be effectively dissipated to the outside of the in-wheel motor 11.

FIGS. 3A to 3C show details of the attachment of the PCU board 25 and the Hall element board 27 to the board case 26. FIG. 3A shows the PCU board 25 side of the board case 26, FIG. 3B shows the opposite Hall element board 27 side, and FIG. 3C shows a cross section. The PCU board 25 and the Hall element board 27 are respectively mounted on opposing surfaces of the board case 26 at positions that do not overlap with each other. The PCU board 25 is mounted such that a power element 251 such as an FET of the inverter 102 provided thereon is in direct contact with the board case 26. Thereby, heat from the power element 251 is efficiently transmitted to the substrate case 26. The Hall element 271 on the Hall element substrate 27 is provided at an end on the rotor side to detect the rotational position of the rotor 23. The board case 26 is configured so that its outer periphery is surrounded by the stator 243, and is coupled to the shaft 112 at the center. The shaft 112 is formed in a hollow shape with both ends open, and provided with

holes

41 and 42 communicating with the surface of the wheel case on which the PCU board 25 is mounted. Cables (or harnesses) 40 such as a power supply cable and other control signals guided from a power supply mounted on the main body of the motorcycle 1 and inserted into the hollow shaft from the end of the shaft 112 have

holes

41 and 42. It is guided to the PCU board 25 via the PCU and is connected to a predetermined terminal. The cable connecting the PCU board 25 and the hall element board 27 is routed through the opening 43 of the board case 26. As described above, the PCU board 25 and the Hall element board 27 are mounted on the opposite sides of the board case 26.

によって With such a configuration, the wiring between the PCU board 25 and the Hall element board 27 can be simplified, and the configuration of the in-wheel motor 11 can be made compact. Furthermore, the fact that the wiring to the inside of the in-wheel motor 11 is realized through the hollow shaft 112 also contributes to downsizing of the in-wheel motor 11. Further, since the PCU board 25 and the Hall element board 27 are provided at positions that do not overlap each other, it is possible to reduce the influence of the heat generated by the inverter 102 on the PCU board 25, particularly on the Hall element circuit 27.

In the present embodiment, the fins provided on the case are arranged in parallel in a certain direction, but the invention is not limited to this. For example, they may be arranged radially around the shaft. Further, the shape may be not only a linear shape but also a curved shape. Further, the shape may be determined in consideration of not only the heat radiation efficiency but also the wind noise and the like.

In the present embodiment, the vehicle using the in-wheel motor 11 as power is a two-wheeled vehicle, but may be a three-wheeled vehicle or a four-wheeled vehicle. The drive wheels are not limited to the rear wheels, but may be the front wheels, or may be all the wheels of the vehicle. Further, the motorcycle is not limited to a vehicle having wheels in front and rear, but may be a vehicle having wheels parallel to the traveling direction such as a wheelchair. In that case, both wheels become drive wheels and are driven by the in-wheel motor 11. In the case of such a two-wheeled vehicle or a four-wheeled vehicle, the in-wheel motor 11 may be configured to be able to reversely rotate (that is, retreat) under the control of the controller 101. Further, the in-wheel motor 11 according to the present embodiment may be used as a power source for rotating an object without being limited to the driving wheels of the vehicle. When the in-wheel motor 11 is used as a driving wheel of the vehicle, a member that efficiently guides the traveling wind to the hub of the driving wheel may be attached to the vehicle.

● Summary of Embodiment The following is a summary of the embodiment described above.
(1) According to the first invention according to the present embodiment, the structure of the motor (11) is
A stator (24);
A rotor (23) rotated by a magnetic force from the stator (24);
A case (21, 29) of the motor connected to the rotor (23);
A power control unit (10) disposed inside the case (21, 29) for driving the stator (24);
A structure of a motor is provided, wherein cooling fins (111) are provided in the cases (21, 29).
Thereby, the case rotates together with the rotation of the rotor, and the air flow easily occurs, so that the cooling efficiency of the motor can be further improved.

(2) According to the second aspect of the present embodiment, the motor (11) has the structure of (1),
The power control unit (10) is attached to a heat conducting member (26) fixed to the stator (24),
In the case (21, 29), the fin (111) is provided on a side surface through which a shaft rotating together with the rotor (23) passes, and an inner surface facing the heat conducting member (26). A featured motor structure is provided.
Thus, cooling fins are provided inside the case, and the cooling effect can be further improved.

(3) According to the third invention of the present embodiment, the structure of the motor (11) of (2) is
A motor structure is provided in which the heat conducting member (26) is provided with cooling fins (111) on a surface facing the inner surface of the case (21, 29).
Thereby, the cooling effect can be further improved by providing the heat conduction member with the cooling fins.

(4) According to a third aspect of the present invention, there is provided the motor (10) according to any one of (1) to (3),
A hollow shaft (112) rotatable with respect to the case (21, 29), which is fixed to the stator (24) and serves as an axis of the case (21, 29) rotating with the rotor (23). )
A motor structure is provided in which a harness connected to the power control unit (10) is inserted into the shaft (112) and wired to the inside of the cases (21, 29). .
As a result, the wiring efficiency inside the motor can be improved, and the size of the motor can be reduced.

(5) According to the third aspect of the present embodiment, the tire (12) is mounted on the outer periphery of the case (21, 29) of the motor (11) having any one of the structures (1) to (4). A vehicle is provided having driving wheels mounted thereon.
As a result, the case rotates with the traveling of the vehicle, and the air flow is likely to occur, so that the cooling efficiency can be further improved.

The present invention is not limited to the above embodiment, and various changes and modifications can be made without departing from the spirit and scope of the present invention.

This application claims the priority of Japanese Patent Application No. 2018-184939 filed on Sep. 28, 2018, the entire contents of which are incorporated herein by reference.

Claims

The structure of the motor (11),
A stator (24);
A rotor (23) rotated by a magnetic force from the stator (24);
A case (21, 29) of the motor connected to the rotor (23);
A power control unit (10) disposed inside the case (21, 29) for driving the stator (24);
A motor structure, wherein cooling fins (111) are provided on the cases (21, 29).
The structure of the motor (11) according to claim 1,
The power control unit (10) is attached to a heat conducting member (26) fixed to the stator (24),
In the case (21, 29), the fin (111) is provided on a side surface through which a shaft rotating together with the rotor (23) passes, and an inner surface facing the heat conducting member (26). Characteristic motor structure.
The structure of the motor (11) according to claim 2,
The motor structure, wherein the heat conducting member (26) is provided with cooling fins (111) on a surface facing an inner surface of the case (21, 29).
It is a structure of the motor (11) according to any one of claims 1 to 3,
A hollow shaft (112) rotatable with respect to the case (21, 29), which is fixed to the stator (24) and serves as an axis of the case (21, 29) rotating with the rotor (23). )
A motor structure, wherein a harness connected to the power control unit (10) is inserted into the shaft (112) and wired to the inside of the cases (21, 29).
A vehicle comprising a motor (11) having a structure according to any one of claims 1 to 4, having a drive wheel with a tire (12) mounted on an outer periphery of the case (21, 29).