JP7156892B2 - Motor structure - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle using, for example, an electric motor as a drive source, and more particularly to the structure of the motor.

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

Patent No. 5169280

In order to make the configuration of the in-wheel motor more compact, there is a configuration in which the motor and the power control unit (PCU) are integrated. When the PCU is integrated with the motor, the in-wheel motor has a structure that is housed inside the wheel. Therefore, from the viewpoint of circuit protection, it is desirable to provide the PCU inside the motor. In such a configuration, it is necessary to dissipate heat not only from the motor but also from the PCU. However, in the conventional technology, the heat pipe is provided through the axle of the wheel, and there is a limit to the thickness.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a motor structure capable of efficiently cooling a motor incorporating a power control unit.

In order to achieve the above objects, the present invention has the following configurations. That is, according to one aspect of the present invention, a structure of a motor (11), comprising:
a stator (24);
a rotor (23) rotated by the magnetic force from the stator (24);
a motor case (21, 29) connected to the rotor (23);
a power control unit (10) for driving the stator (24) disposed inside the case (21, 29);
said power control (10) being mounted on a heat conducting member (26) fixed relative to said stator (24);
The cases (21, 29) have a pair of side surfaces through which a shaft (112) that rotates together with the rotor (23) passes ,
The pair of side surfaces of the case (21, 29) are provided with cooling fins (111) on the inner surface facing the heat conducting member (26) and the outer surface on the back side thereof ,
The electric power control unit (10) is attached to one surface of the heat conduction member (26), and a Hall sensor for detecting the rotational position of the rotor (23) is mounted on the other surface of the heat conduction member (26). A motor structure is provided characterized in that a Hall element substrate (27) provided with is mounted.

ADVANTAGE OF THE INVENTION According to this invention, the motor which incorporated the electric power control part can be cooled efficiently.

(a) It is a figure which shows the external appearance of the two-wheeled vehicle of embodiment. 3B is a block diagram of a motor drive control circuit; FIG. (a) It is an exploded perspective view of an in-wheel motor of an embodiment. (b) It is sectional drawing of the in-wheel motor of embodiment. It is the figure which showed the arrangement|positioning of the circuit board in the in-wheel motor of embodiment. It is a figure which shows the cooling principle at the time of the drive of the in-wheel motor of embodiment.

[First embodiment]
●Structure of Straddle-Type Vehicle FIG. 1A shows an example of the appearance of a powered two-wheeled vehicle 1 that is a straddle-type vehicle according to the present embodiment. The two-wheeled vehicle 1 has an in-wheel motor (hereinafter simply referred to as a motor) 11 as a drive source, and a tire 12 is mounted around the in-wheel motor 11 as a hub. The in-wheel motor 11 is pivotally supported by the swing arm 13 with its shaft 112, and can directly rotate the driving wheels without using a speed reduction mechanism or a transmission mechanism. Cooling fins 111 are provided on both side surfaces of the in-wheel motor 11. Rotation causes an air flow on the surface of the in-wheel motor 11 to efficiently dissipate the 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. 1(b)), and the number of rotations of the in-wheel motor 11 is determined by the driver pressing the accelerator provided on the grip of the steering wheel. controlled by manipulation.

FIG. 1(b) shows a block diagram of a control circuit for drive control of the in-wheel motor 11. As shown in FIG. The in-wheel motor 11 of the present embodiment is structurally an outer rotor type surface magnet synchronous motor (SPMSM), and is sometimes called 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 this AC power supply may be a sine wave or a square wave. The PCU 10 is driven by a low voltage power supply (eg, 12V power supply) 104 and includes a controller 101 and an inverter 102 . The controller 101 receives a Hall sensor output signal (a Hall sensor signal) for detecting the rotational position of the rotor from the motor 103 . Note that the motor 103 refers to a portion of the in-wheel motor 11 excluding the PCU. The controller 101 inputs a control signal to the inverter 102 for controlling switching of the current from the high voltage power supply (HV battery) 105 based on the input Hall sensor signal. Controller 101 further adjusts the timing of the control signal to inverter 102 in order to control the output frequency of inverter 102 in accordance with the signal indicating the degree of accelerator opening. Furthermore, the configuration may be such that not only the frequency but also the current can be controlled.

Inverter 102 converts high-voltage power supply 105 into three-phase alternating currents U, V, and W according to a control signal from controller 101 , and inputs the three-phase alternating currents U, V, W to motor 103 . The motor 103 is driven in synchronization with the frequency of the input power supply. The motor 103 has a temperature sensor and a Hall sensor, and a temperature signal indicating the temperature detected by the temperature sensor and a Hall sensor signal indicating the magnetic field detected by the Hall sensor are input to the controller 101 . Hall sensor signals detect the electrical rotational position of the rotor by detecting the magnetic field of permanent magnets attached to the surface of the rotor so that the S and N poles alternate.

Here, in this embodiment, the PCU 10 is incorporated inside the in-wheel motor 11 as will be described later. Using the in-wheel motor 11 configured in this manner, the drive wheels of the two-wheeled vehicle 1 can be rotated and the two-wheeled vehicle 1 can be driven as intended by the driver.

●Configuration of In-wheel Motor FIG. 2(a) is an exploded perspective view of the in-wheel motor 11. FIG. The main components of the in-wheel motor 11 are housed inside a housing composed of a wheel case 21 and a wheel case 29 made of metal or the like. The wheel case 21 is provided with a hole through which the shaft 112 is passed in its rotating shaft portion, and has a disc shape with a protruding peripheral portion. Further, fins 111 for heat dissipation are provided on the outer and inner surfaces thereof. The fins 111 , in this example, are a plurality of elongated overhangs parallel to each other and integrally formed with the wheel case 21 . In order to release the heat generated inside the in-wheel motor 11, the height and the number thereof may be determined according to the amount of heat generated. The wheel case 29 has the same configuration as the wheel case 21, but in this example, there is no overhanging peripheral portion provided on the outer peripheral portion. However, the same configuration as the wheel case 21 may be used. The wheel case 21 and the wheel case 29 are fixed to each other, for example, by bolts or the like to constitute 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 are fixed to the swing arm 13 and can rotate with respect to the shaft 112 which does not rotate, and the tire 12 is attached to the outer periphery thereof, which also serves as the hub of the driving wheel.

A 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, such as 16 or 32, with their polarities alternately reversed. This is the same as 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 disk-shaped member made of metal centered on the shaft 112 . A portion of the surface of the circuit case 26 facing the wheel case 29 is preferably provided with fins for heat dissipation that are integrally formed 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 on which the PCU 10 is provided 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 drilled in the circuit case 26 . Fins are not provided on the surface of the circuit case 26 on the PCU board 25 side in this example, but they may be provided.

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

FIG. 2B is a cross-sectional view showing a cross section parallel to the rotating shaft of the in-wheel motor 11. As shown in FIG. A rotor 23 , a stator 24 , a substrate case 26 and the like are accommodated in a housing constituted by the wheel cases 21 and 29 with the shaft 112 as an axis. Here, the substrate case 26 is a heat conductive member such as metal having high thermal conductivity, and functions as a member for mounting substrates and also as a heat sink. Therefore, the PCU board 25 may be attached to the board case 26 so that the heat-generating components attached thereon are in contact with the board case 26 either directly or via a heat-conducting material having a high thermal conductivity. Furthermore, the stator 24 is also in contact with the board case 26 and the heat is propagated to the board case 26 . As a result of such a configuration, heat from the stator 24 and the PCU board 25 is easily transferred to the board case 26 . The surface of the substrate case 26 on which the fins are provided faces the wheel case 29 , and the rotation of the wheel case 29 causes an air flow in the space between the substrate case 26 and the wheel case 29 . This airflow 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 it be attached so that the heat from the substrate case 26 is less likely to propagate to the Hall elements.

The situation is shown in FIG. 4 shows the board case 26 and the wheel case 29 from the shaft 112 in the cross section of FIG. 2(b). As the wheel case 29 rotates, an air flow is generated along the wheel case 29 toward the outer peripheral side. The airflow is directed toward the shaft 112 side by the substrate case 26 and collides with the airflow also generated on the opposite side of the shaft 112 to cause vortex convection as shown by arrows in FIG. Due to this air flow, the heat generated by the PCU board 25 , the Hall element board 27 , the stator 24 and the like and transferred to the board case 26 is further transferred to the wheel case 29 . Heat is effectively radiated 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 .

3(a) to 3(c) show the details of mounting the PCU board 25 and Hall element board 27 to the board case 26. FIG. 3(a) shows the side of the PCU board 25 of the board case 26, FIG. 3(b) shows the opposite Hall element board 27 side, and FIG. 3(c) shows a cross section. The PCU board 25 and the Hall element board 27 are mounted on the facing surfaces of the board case 26 at positions that do not overlap each other. The PCU board 25 is attached so that the power elements 251 such as FETs of the inverter 102 provided thereon are in direct contact with the board case 26 . Thereby, heat from the power element 251 is efficiently propagated to the substrate case 26 . A Hall element 271 on the Hall element substrate 27 is provided at the end on the rotor side in order to detect the rotational position of the rotor 23 . The substrate case 26 is configured such that its outer peripheral portion is surrounded by the stator 243 and is coupled to the shaft 112 at its central portion. The shaft 112 is hollow with open ends, and is provided with holes 41 and 42 leading to the side of the wheel case on which the PCU board 25 is mounted. A cable (or harness) 40 such as a power cable and other control signals guided from a power source mounted on the main body of the motorcycle 1 and inserted from the end of the shaft 112 into the hollow shaft passes through the holes 41 and 42 . It is led to the PCU board 25 via the PCU board 25 and connected to a predetermined terminal. A cable connecting the PCU board 25 and the Hall element board 27 is routed through the opening 43 of the board case 26 . In this manner, the PCU board 25 and the Hall element board 27 are mounted on opposite surfaces of the board case 26 .

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 inside the in-wheel motor 11 is routed through the hollow shaft 112 also contributes to the compactness of the in-wheel motor 11 . In addition, since the PCU board 25 and the Hall element board 27 are provided at positions that do not overlap each other, the influence of the heat generated by the PCU board 25, especially the inverter 102, on the Hall element circuit 27 can be reduced.

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

In this embodiment, the vehicle using the in-wheel motor 11 as power is a two-wheeled vehicle, but it may be a three-wheeled vehicle or a four-wheeled vehicle. Also, the driving wheels are not limited to the rear wheels, but may be the front wheels, or may be all the wheels of the vehicle. The two-wheeled vehicle is not limited to having front and rear wheels, and may be a vehicle such as a wheelchair having wheels parallel to the left and right with respect to the direction of travel. In that case, both wheels become drive wheels and are driven by the in-wheel motor 11 . Further, in the case of such a two-wheeled vehicle or four-wheeled vehicle, the in-wheel motor 11 may be configured to rotate in reverse (that is, move backward) under the control of the controller 101 . Furthermore, the in-wheel motor 11 according to the present embodiment may be used as a power source for rotating an object other than the driving wheels of the vehicle. Furthermore, when the in-wheel motor 11 is used as the drive wheels of the vehicle, a member may be attached to the vehicle to efficiently guide the running wind to the hub portions of the drive wheels.

●Summary of Embodiments The above-described embodiments are summarized as follows.
(1) According to the first aspect of the present invention, the structure of the motor (11) is
a stator (24);
a rotor (23) rotated by the magnetic force from the stator (24);
a motor case (21, 29) connected to the rotor (23);
a power control unit (10) for driving the stator (24) disposed inside the case (21, 29);
A motor structure is provided, characterized in that the case (21, 29) is provided with cooling fins (111).

As a result, the case rotates with the rotation of the rotor, making it easier for the air to flow, so that the cooling efficiency of the motor can be further improved.
(2) According to the second aspect of the present invention, the structure of the motor (11) of (1) is
said power control (10) being mounted on a heat conducting member (26) fixed relative to said stator (24);
The case (21, 29) is provided with the fins (111) on the side surface through which the shaft rotating together with the rotor (23) passes and the inner surface facing the heat conducting member (26). A featured motor structure is provided.

As a result, cooling fins are provided inside the case, and the cooling effect can be further improved.
(3) According to the third aspect of the present invention, the structure of the motor (11) of (2),
A motor structure is provided in which the heat conducting member (26) is provided with cooling fins (111) on the surface facing the inner surface of the case (21, 29).

Accordingly, the cooling effect can be further improved by providing cooling fins on the heat conducting member as well.
(4) According to the third aspect of the present invention, the structure of the motor (10) according to any one of (1) to (3),
a hollow shaft (112) fixed to the stator (24) and rotatable with respect to the case (21,29), which pivots the case (21,29) rotating with the rotor (23); ), and
A motor structure is provided in which a harness connected to the power control unit (10) is inserted through the shaft (112) and wired to the inside of the case (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 characterized by having attached drive wheels.

As a result, the case rotates as the vehicle travels, making it easier for the air to flow, so that the cooling efficiency can be further improved.

The present invention is not limited to the embodiments described above, and various modifications and variations are possible without departing from the spirit and scope of the present invention.

Claims (5)

A structure of a motor (11),
a stator (24);
a rotor (23) rotated by the magnetic force from the stator (24);
a motor case (21, 29) connected to the rotor (23);
a power control unit (10) for driving the stator (24) disposed inside the case (21, 29);
said power control (10) being mounted on a heat conducting member (26) fixed relative to said stator (24);
The cases (21, 29) have a pair of side surfaces through which a shaft (112) that rotates together with the rotor (23) passes ,
The pair of side surfaces of the case (21, 29) are provided with cooling fins (111) on the inner surface facing the heat conducting member (26) and the outer surface on the back side thereof ,
The electric power control unit (10) is attached to one surface of the heat conduction member (26), and a Hall sensor for detecting the rotational position of the rotor (23) is mounted on the other surface of the heat conduction member (26). A structure of a motor characterized in that a Hall element substrate (27) provided with is mounted. A structure of a motor (11) according to claim 1, comprising:
The heat conducting member (26) is fixed to the stator (24) at a position offset from the center of the cases (21, 29) in the longitudinal direction of the shaft (112),
A structure of a motor, wherein the Hall element substrate (27) is attached to the other surface of the heat conducting member (26) and a fin is provided. A structure of a motor (11) according to claim 2, comprising:
A structure of a motor, wherein cooling fins (111) are provided on the surface of the heat conducting member (26) facing the inner surfaces of the cases (21, 29). A structure of a motor (11) according to any one of claims 1 to 3,
The shaft (112) is fixed to the stator (24) and pivots relative to the cases (21, 29) which are pivots of the cases (21, 29) rotating with the rotor (23). possible hollow shaft,
A motor structure characterized in that a harness connected to the power control unit (10) is inserted through the shaft (112) and wired to the inside of the case (21, 29). A vehicle comprising drive wheels having tires (12) attached to the outer periphery of the case (21, 29) of the motor (11) having the structure according to any one of claims 1 to 4.

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