JP2020156268A - Motor unit - Google Patents

Abstract

To provide a motor unit in which an inverter and a motor are integrated, capable of improving a cooling efficiency of a motor without providing a fin structure separated from a motor.SOLUTION: An inverter 3 includes a plurality of inverter heat radiation fins 3e arranged in a peripheral direction as a center of a shaft 2d in view of an extension direction of the shaft 2d. A motor 2 includes a motor heat radiation fin 2e in which at least one part of the plurality of them is arranged between the inverter heat radiation fins 3e in view of the extension direction of the shaft 2d while being arranged in the peripheral direction as a center of the shaft 2d in view of the extension direction of the shaft 2d.SELECTED DRAWING: Figure 1

Description

The present invention relates to a motor unit.

In recent years, it has been proposed to mount a motor unit in which a motor and a fan are integrated in a vehicle such as a small motorcycle. For example, Patent Document 1 discloses a motor unit in which a fan is installed on a shaft of a motor. The motor unit disclosed in Patent Document 1 cools the inverter by blowing air from a fan to the inverter.

JP-A-2017-147919 Japanese Unexamined Patent Publication No. 2014-50173

By the way, in the motor unit, not only the inverter but also the motor generates heat, so it is preferable to cool the motor as well. In such a case, it is conceivable that the air blown by the fan described above flows not only along the inverter but also along the motor housing. However, the cooling effect of the motor by blowing the fan is not sufficient, and a proposal to make the motor cooler is desired.

For example, Patent Document 2 discloses a structure that enhances the cooling efficiency of a motor by attaching a separate fin structure to the motor. However, when such a separate fin structure is used, it is necessary to form the fin structure separately from the motor and to attach the fin structure to the motor, and further to improve the heat transfer efficiency from the motor to the fin structure. You will need it.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to improve the cooling efficiency of a motor in a motor unit in which an inverter and a motor are integrated without providing a fin structure separately from the motor. And.

The present invention adopts the following configuration as a means for solving the above problems.

The first invention is a motor unit including a motor, an inverter connected to the motor, and a fan for pumping air toward the inverter, from the direction in which the inverter extends from the direction in which the shaft of the motor extends. It has a plurality of inverter heat radiation fins arranged in the circumferential direction centered on the shaft, and the motors are arranged in the circumferential direction centered on the shaft when viewed from the direction in which the shaft of the motor extends. At the same time, a configuration is adopted in which at least a part of the plurality of inverter heat radiation fins is arranged between the inverter heat radiation fins when viewed from the direction in which the shaft of the motor extends.

In the first invention, the fan, the inverter, and the motor are arranged in this order, and the second invention covers the fan and causes the air flow between the inverter and the outer wall portion of the motor. A fan cover that forms a path is provided, and the fan cover adopts a configuration that covers from the fan to a part of the motor on the inverter side.

In the third invention, in the first or second invention, the end portion of the motor radiating fin on the inverter side is formed to have a sharp shape toward the inverter.

In the fourth invention, in any one of the first to third inventions, the motor radiating fin adopts a configuration in which the width dimension increases as the distance from the root on the erection surface side to the erection surface. ..

The fifth invention adopts the configuration in which the inverter heat radiation fins are installed more than the motor heat radiation fins in any one of the first to fourth inventions.

In the sixth invention, in the fifth invention, the surface area of the motor radiating fin is set wider than that of the inverter radiating fin when viewed from the direction in which the shaft of the motor extends.

According to the present invention, the inverter heat radiation fins and the motor heat radiation fins are arranged so as to be displaced when viewed from the direction in which the shaft of the motor extends. Therefore, the air traveling along the inverter heat dissipation fins collides with the end portion of the motor heat dissipation fins, so that the boundary layer of air can be thinned and the heat dissipation efficiency from the motor heat dissipation fins can be improved. Therefore, according to the present invention, it is possible to improve the cooling efficiency of the motor. Further, according to the present invention, since the inverter heat radiation fin is provided in the inverter and the motor heat radiation fin is provided in the motor, it is not necessary to provide the fin structure separately from the inverter and the motor. Therefore, according to the present invention, in a motor unit in which an inverter and a motor are integrated, it is possible to improve the cooling efficiency of the motor without providing a fin structure separately from the motor.

It is sectional drawing which shows typically the schematic structure of the motor unit in one Embodiment of this invention. It is a perspective view of the motor housing included in the motor unit in one Embodiment of this invention. It is a perspective view of the inverter housing included in the motor unit in one Embodiment of this invention. (A) is a cross-sectional view of passing through the inverter heat radiation fins seen from the direction along the axial center of the shaft, and (b) is the boundary between the motor housing and the inverter housing seen from the direction orthogonal to the axial center of the shaft. It is a schematic diagram which shows a part. FIG. 1 is a sectional view taken along the line AA of FIG. It is a schematic diagram which shows the 1st modification of the motor heat radiation fin provided in the motor unit in one Embodiment of this invention. It is a schematic diagram which shows the 2nd modification of the motor heat radiation fin provided in the motor unit in one Embodiment of this invention. It is a schematic diagram which shows the 3rd modification of the motor heat radiation fin provided in the motor unit in one Embodiment of this invention.

Hereinafter, an embodiment of the motor unit according to the present invention will be described with reference to the drawings.

FIG. 1 is a cross-sectional view schematically showing a schematic configuration of the motor unit 1 of the present embodiment. As shown in this figure, the motor unit 1 of the present embodiment includes a motor 2, an inverter 3, a fan 4, a fan cover 5, and a gear unit 6.

The motor 2 includes a motor housing 2a, a stator core 2b, a rotor core 2c, and a shaft 2d. The motor housing 2a is a housing that houses the stator core 2b, the rotor core 2c, and the shaft 2d. FIG. 2 is a perspective view of the motor housing 2a. As shown in this figure, a plurality of motor heat radiation fins 2e extending along the extending direction of the shaft 2d are provided on the outer wall portion of the motor housing 2a arranged in the circumferential direction centered on the shaft 2d. Further, as shown in FIG. 2, the outer wall portion of the motor housing 2a has a frame fixing portion 2f for fixing the motor unit 1 of the present embodiment to the vehicle body frame and an inverter for fixing the inverter housing 3a described later. It has a fixed portion of 2 g. The frame fixing portion 2f and the inverter fixing portion 2g are stretched along the stretching direction of the shaft 2d.

The stator core 2b is fixed to the inner wall of the motor housing 2a and is provided in an annular shape so as to surround the rotor core 2c. The stator core 2b generates a magnetic force that rotates the rotor core 2c by supplying power. The rotor core 2c is arranged inside the stator core 2b and is fixed to the shaft 2d. The rotor core 2c is made rotatable by the magnetic force generated by the stator core 2b.

The shaft 2d is fixed to the rotor core 2c and is rotated as the rotor core 2c rotates. In the present embodiment, the shaft 2d is pivotally supported by a bearing fixed to the motor housing 2a, the tip portion is fixed to the fan 4 through the inverter 3, and the rear end portion is a gear (not shown). It is fixed to. Such a shaft 2d transmits the rotational power generated by the stator core 2b and the rotor core 2c to the fan and gears (not shown).

In such a motor 2, electric power converted into three-phase AC by the inverter 3 is supplied, rotational power is generated from the supplied electric power, and the generated rotational power is transmitted to the fan 4 and the gear unit 6 by the shaft 2d. To do.

The inverter 3 has an inverter housing 3a and a core unit 3b. The inverter housing 3a is a cover member that covers the core unit 3b, and also functions as a heat sink that absorbs the heat of the core unit 3b and releases it to the outside. That is, in the present embodiment, the cover member covering the core unit 3b and the heat sink that absorbs the heat of the core unit 3b and releases the heat to the outside are integrated as the inverter housing 3a. The core unit 3b is housed inside the inverter housing 3a in a state of being fixed to the inverter housing 3a. The core unit 3b converts DC power supplied from a battery (not shown) into three-phase AC and supplies it to the stator core 2b of the motor 2. Such a core unit 3b includes six switching elements, a substrate (not shown) on which a capacitor or the like is mounted, or the like.

FIG. 3 is a perspective view of the inverter housing 3a. The inverter housing 3a is integrally formed of a metal having high thermal conductivity (for example, aluminum), and as shown in FIG. 3, the surrounding wall 3c, the heat radiating portion 3d, the inverter heat radiating fins 3e, and the inverter housing 3a are formed. It has a fixing portion 3f used for attaching to the motor 2 with a screw or the like.

The surrounding wall 3c is a bowl-shaped portion that accommodates the core unit 3b, and has a top wall portion 3c1 and a side wall portion 3c2. The top wall portion 3c1 is a portion that covers the core unit 3b when viewed from the fan 4 side, and the edge portion to which the side wall portion 3c2 is connected is curved toward the motor 2 side. A heat radiating portion 3d is provided on the outer wall surface (surface on the fan 4 side) of the top wall portion 3c1. Further, when viewed from the fan 4 side, a through opening 3c3 penetrating the top wall portion 3c1 is provided in the central portion of the top wall portion 3c1. The shaft 2d of the motor 2 is inserted through the through opening 3c3.

The side wall portion 3c2 extends from the edge portion of the top wall portion 3c1 along the side surface of the core unit 3b so as to surround the top wall portion 3c1. That is, the side wall portion 3c2 extends from the top wall portion 3c1 toward the motor 2 side along the shaft 2d. The side wall portion 3c2 surrounds the core unit 3b so as to cover it from the side (the radial outside of the shaft 2d).

Such a surrounding wall 3c accommodates the core unit 3b in a space surrounded by the top wall portion 3c1 and the side wall portion 3c2, protects the core unit 3b from foreign matter, and absorbs heat from the core unit 3b to dissipate heat. It is transmitted to the unit 3d and the inverter heat dissipation fin 3e.

The heat radiating unit 3d has a plurality of heat radiating fins. The heat radiating unit 3d releases the heat generated by the core unit 3b transmitted through the surrounding wall 3c to the air flow blown from the fan 4. In the present embodiment, the outer wall surface of the top wall portion 3c1 of the surrounding wall 3c is arranged to face the fan 4, and is a wind receiving region that receives the air blown from the fan 4 from the front. The heat radiating portion 3d is provided on the outer wall surface of the top wall portion 3c1 of the surrounding wall 3c, which is such a wind receiving region.

The inverter heat radiation fin 3e is erected on the outer wall surface of the side wall portion 3c2 of the surrounding wall 3c, and is a plate-shaped portion extending along the extending direction of the side wall portion 3c2 from the top wall portion 3c1. The inverter heat radiation fins 3e are arranged at equal intervals in the circumferential direction centered on the through opening 3c3, avoiding the region where the fixed portion 3f is provided.

FIG. 4 is a schematic view for explaining the positional relationship between the motor heat radiation fin 2e included in the motor 2 and the inverter heat radiation fin 3e included in the inverter 3, and FIG. 4A is a direction along the axial direction of the shaft 2d. It is sectional drawing which passes through the inverter heat radiation fin 3e seen from the view, and is the figure which shows the boundary part between the motor housing 2a and the inverter housing 3a seen from the direction which is orthogonal to the axis of shaft 2d. As shown in these figures, the motor radiating fins 2e, the inverter radiating fins 3e, and the shaft 2d are arranged at positions displaced by a half pitch in the circumferential direction. That is, in the present embodiment, the inverter 3 has a plurality of inverter heat radiation fins 3e arranged in the circumferential direction about the shaft 2d when viewed from the extension direction of the shaft 2d, and the motor 2 extends the shaft 2d. It has motor heat radiation fins 2e arranged in the circumferential direction centered on the shaft 2d when viewed from the direction and arranged between the inverter heat radiation fins 3e when viewed from the extension direction of the shaft 2d.

In the present embodiment, as shown in FIG. 4, the arrangement interval of the plurality of motor heat radiation fins 2e and the arrangement interval of the plurality of inverter heat radiation fins 3e are the same. Further, the inverter heat radiation fins 3e are arranged at intermediate positions between the adjacent motor heat radiation fins 2e and the motor heat radiation fins 2e when viewed from the extending direction of the shaft 2d. Further, the motor heat radiation fins 2e are arranged at intermediate positions between the adjacent inverter heat radiation fins 3e and the inverter heat radiation fins 3e when viewed from the extending direction of the shaft 2d.

Returning to FIG. 1, the fan 4 is arranged in a state of facing the heat radiating portion 3d with a certain gap, and is fixed to the shaft 2d of the motor 2. The fan 4 is rotated via the shaft 2d to take in air from the side opposite to the heat radiating portion 3d and pump the air toward the heat radiating portion 3d side. That is, the fan 4 forms an air flow toward the heat radiating portion 3d by transmitting rotational power from the motor 2 and rotating the fan 4.

The fan cover 5 is formed of, for example, resin, and is fixed to the inverter housing 3a. The fan cover 5 has a top wall portion 5b provided with a suction opening 5a, and a peripheral wall portion 5c extending from the peripheral edge portion of the top wall portion 5b.

The top wall portion 5b is a portion that covers the fan 4 from the air inflow side, and is arranged on the right side of the fan 4. The suction opening 5a is provided with a mesh portion or the like for preventing the intrusion of foreign matter, if necessary.

The peripheral wall portion 5c is a portion that surrounds the fan 4 from the outside in the radial direction. FIG. 5 is a cross-sectional view taken along the line AA of FIG. As shown in this figure, the peripheral wall portion 5c is arranged so as to cover the side wall portion 3c2 of the surrounding wall 3c of the inverter housing 3a from the outside in the radial direction with a certain gap when viewed from the extending direction of the shaft 2d. The peripheral wall portion 5c is set to extend from the top wall portion 5b so as to reach the motor heat radiation fin 2e of the motor housing 2a from the fan 4. That is, as shown in FIG. 1, the peripheral wall portion 5c covers from the fan 4 to a part of the motor 2 on the inverter 3 side. The peripheral wall portion 5c is arranged with a certain gap between the side wall portion 3c2 of the surrounding wall 3c of the inverter housing 3a and the outer wall portion of the motor housing 2a, and is pumped by a fan 4 between the inverter 3 and the motor 2. It forms an exhaust flow path for the air. Such a peripheral wall portion 5c guides the air pumped by the fan 4 along the outer wall surface of the motor housing 2a through the discharge flow path.

The gear unit 6 is arranged on the side opposite to the inverter 3 of the motor 2, and adjusts and outputs the rotation speed of the rotational power transmitted from the motor 2. Such a gear unit 6 has, for example, the same diameter as the motor 2. By making the gear unit 6 have the same diameter or a smaller diameter as the motor 2, the flow of air flowing along the motor housing 2a is not obstructed by the gear unit 6, and the air flows smoothly along the motor housing 2a. Is possible. For example, in order to make the gear unit 6 have the same diameter or a smaller diameter as the motor 2, the gear unit 6 has a structure using a planetary gear mechanism.

In such a motor unit 1 of the present embodiment, when power is supplied to the motor 2 via the inverter 3, rotational power is generated by the motor 2 and the tire of the vehicle is generated from the motor 2 via a gear unit 6 (not shown). Power is transmitted to such as. Further, a part of the rotational power generated by the motor 2 is transmitted to the fan 4 through the shaft 2d, and the fan 4 is rotationally driven.

When the fan 4 is rotationally driven, air is taken into the inside of the fan cover 5 from the suction opening 5a of the fan cover 5, and an air flow toward the heat radiating portion 3d of the inverter housing 3a is formed. The air flow formed by the fan 4 spreads in the radial direction around the through opening 3c3 after hitting the heat radiating portion 3d, and then passes through the space between the side wall portion 3c2 of the surrounding wall 3c and the fan cover 5 to cover the fan cover 5. It is discharged to the outside of.

Heat is radiated from the heat radiating fin of the heat radiating unit 3d to the air flow as described above, and is also radiated to the air flow from the inverter heat radiating fin 3e. As a result, the heat generated by the core unit 3b of the inverter 3 is discharged to the outside of the inverter 3 via the air flow.

Further, the air pumped by the fan 4 is guided by the peripheral wall portion 5c of the fan cover 5, and is discharged from the fan cover 5 so that the peripheral surfaces of the inverter housing 3a and the motor housing 2a are along the extending direction of the shaft 2d. At this time, heat is radiated from the inverter heat radiating fin 3e and the motor heat radiating fin 2e with respect to the discharged air flow, and the inverter 3 and the motor 2 are cooled. Here, in the present embodiment, the inverter heat radiation fins 3e and the motor heat radiation fins 2e are arranged so as to be displaced in the circumferential direction about the shaft 2d. Therefore, the air traveling along the inverter heat radiation fin 3e collides with the end portion of the motor heat radiation fin 2e. As a result, the boundary layer of the air flow formed on the surface of the motor heat dissipation fin 2e is thinned, and heat dissipation from the motor 2 to the air is promoted.

In the motor unit 1 of the present embodiment as described above, the inverter 3 has a plurality of inverter heat radiation fins 3e arranged in the circumferential direction centered on the shaft 2d when viewed from the extension direction of the shaft 2d, and the motor 2 Are arranged in the circumferential direction centered on the shaft 2d when viewed from the stretching direction of the shaft 2d, and at least a part of a plurality of them is arranged between the inverter heat radiating fins 3e when viewed from the stretching direction of the shaft 2d. It has fins 2e. According to the motor unit 1 of the present embodiment as described above, the inverter heat radiation fins 3e and the motor heat radiation fins 2e are arranged so as to be displaced when viewed from the extending direction of the shaft 2d. Therefore, the air traveling along the inverter heat radiating fin 3e collides with the end of the motor heat radiating fin 2e, so that the boundary layer of air can be thinned and the heat radiating efficiency from the motor heat radiating fin 2e can be improved. it can. Therefore, according to the motor unit 1 of the present embodiment, it is possible to improve the cooling efficiency of the motor 2. Further, according to the motor unit 1 of the present embodiment, since the inverter heat radiation fins 3e are provided in the inverter 3 and the motor heat radiation fins 2e are provided in the motor 2, the fin structure is separate from the inverter 3 and the motor 2. There is no need to provide it. Therefore, according to the motor unit 1 of the present embodiment, in the motor unit 1 in which the inverter 3 and the motor 2 are integrated, the cooling efficiency of the motor 2 is improved without providing a fin structure separately from the motor 2. Is possible.

Further, in the motor unit 1 of the present embodiment, the fan 4, the inverter 3, and the motor 2 are arranged in this order, and the fan 4 is covered and an air flow path is provided between the inverter 3 and the outer wall portion of the motor 2. A fan cover 5 to be formed is provided, and the fan cover 5 covers from the fan 4 to a part of the motor 2 on the inverter 3 side. Therefore, it is possible to prevent the air from leaving the motor unit 1 in the radial direction centered on the shaft 2d until the air pumped to the fan 4 reaches the motor 2. Therefore, it is possible to cool the motor 2 more reliably.

Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to the above embodiment. The various shapes and combinations of the constituent members shown in the above-described embodiment are examples, and can be variously changed based on design requirements and the like without departing from the gist of the present invention.

For example, in the above embodiment, the configuration in which the end surface of the motor heat radiation fin 2e on the inverter 3 side is a closed end surface has been described. However, the present invention is not limited to this. FIG. 6 is a schematic view showing a first modification of the motor heat dissipation fin 2e. As shown in this figure, the end of the motor radiating fin 2e on the inverter 3 side can be shaped sharply toward the inverter 3. By adopting such a configuration, it is possible to suppress the occurrence of turbulent flow when the air flowing along the inverter heat radiation fin 3e collides with the end face of the motor heat radiation fin 2e. Therefore, it is possible to suppress the expansion of the air boundary layer and improve the cooling efficiency of the motor 2.

Further, in the above embodiment, the configuration in which the width dimension of the motor radiating fin 2e (the dimension in the thickness direction of the motor radiating fin 2e) is constant from the root to the tip of the motor radiating fin 2e has been described. However, the present invention is not limited to this. FIG. 7 is a schematic view showing a second modification of the motor heat dissipation fin 2e. As shown in this figure, it is also possible to shape the motor radiating fin 2e so that the width dimension increases as the distance from the root on the erection surface side increases from the erection surface. By adopting such a configuration, the flow path formed between the adjacent motor heat radiation fins 2e and the motor heat radiation fins 2e is formed to be narrowed from the root to the tip of the motor heat radiation fins 2e. be able to. Therefore, it is possible to prevent the air flowing through the flow path formed between the adjacent motor heat radiation fins 2e and the motor heat radiation fin 2e from flowing out from the flow path, and to improve the cooling efficiency of the motor 2. ..

Further, in the above embodiment, the inverter heat radiation fins 3e and the motor heat radiation fins 2e are arranged at the same pitch. However, the present invention is not limited to this. For example, as shown in FIG. 8, the arrangement pitch of the motor radiating fins 2e is wider than the arrangement pitch of the inverter radiating fins 3e, and the inverter radiating fins 3e are installed more than the motor radiating fins 2e. It is also possible. Further, as shown in FIG. 8, in order to set the surface area of the motor heat radiation fin 2e wider than that of the inverter heat radiation fin 3e when viewed from the stretching direction of the shaft 2d, the dimension from the root to the tip of the motor heat radiation fin 2e is set to the inverter. It is also possible to make it larger than the heat radiation fin 3e. By adopting such a configuration, it is possible to reduce the number of motor heat radiating fins 2e without reducing the heat radiating effect of the motor heat radiating fins 2e.

1 ... motor unit, 2 ... motor, 2a ... motor housing, 2b ... stator core, 2c ... rotor core, 2d ... shaft, 2e ... motor heat dissipation fin, 2f ... frame fixing part, 2g ... inverter Fixed part, 3 ... Inverter, 3a ... Inverter housing, 3b ... Core unit, 3c ... Surrounding wall, 3c1 ... Top wall part, 3c2 ... Side wall part, 3c3 ... Through opening, 3d ... Heat dissipation part, 3e …… Inverter heat dissipation fin, 3f …… Fixed part, 4 …… Fan, 5 …… Fan cover, 5a …… Suction opening, 5b …… Top wall part, 5c …… Peripheral wall part, 6 …… Gear unit

Claims (6)

A motor unit including a motor, an inverter connected to the motor, and a fan for pumping air toward the inverter.
The inverter has a plurality of inverter heat radiation fins arranged in the circumferential direction centered on the shaft when viewed from the direction in which the shaft of the motor extends.
The motors are arranged in the circumferential direction centered on the shaft when viewed from the direction in which the shaft of the motor extends, and at least among a plurality of the inverter heat radiation fins when viewed from the direction in which the shaft of the motor extends. A motor unit characterized by having motor radiating fins in which a part is arranged. The fan, the inverter, and the motor are arranged in this order.
A fan cover that covers the fan and forms an air flow path between the inverter and the outer wall portion of the motor is provided.
The motor unit according to claim 1, wherein the fan cover covers from the fan to a part of the motor on the inverter side. The motor unit according to claim 1 or 2, wherein the end of the motor radiating fin on the inverter side has a sharp shape toward the inverter. The motor unit according to any one of claims 1 to 3, wherein the motor radiating fin has a width dimension that increases as the distance from the root on the erection surface side increases from the erection surface. The motor unit according to any one of claims 1 to 4, wherein the inverter heat radiation fins are installed in a larger number than the motor heat radiation fins. The motor unit according to claim 5, wherein the surface area of the motor heat radiating fin is set wider than that of the inverter heat radiating fin when viewed from the direction in which the shaft of the motor extends.

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