JP7364507B2 - In-wheel inverter device - Google Patents

Description

The present invention relates to an in-wheel inverter device.

As the development of in-wheel motors that have a built-in motor and inverter accelerates, there is a need for technology that improves the transmission efficiency from the motor to the wheels by effectively utilizing space.

As background art for the present invention, the following Patent Document 1 is known. Patent Document 1 discloses an electrical component 41 that is installed on a circuit board 40 in order to be installed in the power conversion device 1.

Japanese Patent Application Publication No. 2018-191388

In the technology disclosed in Patent Document 1, due to the structure of an in-wheel motor, the inverter is placed under the springs of the suspension, which causes large vibrations, so if the capacitor, which is an electrical component, is mounted on the board, the reliability of the capacitor may be affected. Securing it was an issue.

An in-wheel inverter device according to the present invention is an in-wheel inverter device that includes an inverter connected to a motor inside, the inverter being a power module housing a power module for converting DC power into AC power. a storage section; a capacitor storage section that stores a capacitor for smoothing the DC power; capacitor pins, and the capacitor is bonded to the printed circuit board using an adhesive and fixed to the printed circuit board via the plurality of capacitor pins.

According to the present invention, reliability of a capacitor in an in-wheel inverter device can be ensured.

It is a perspective view showing the composition of the wheel part provided with the inverter device for in-wheels. FIG. 2 is a cross-sectional view of FIG. 1; It is a circuit diagram of an inverter device for in-wheels. FIG. 3 is a diagram showing the arrangement location of a capacitor storage section in the inverter according to the first embodiment of the present invention. FIG. 3 is a configuration diagram showing a capacitor in a capacitor storage section according to a first embodiment of the present invention. 6 is a sectional view taken along line AA in FIG. 5. FIG. FIG. 7 is a configuration diagram showing a capacitor in a capacitor storage section according to a second embodiment of the present invention. FIG. 7 is a configuration diagram showing a capacitor in a capacitor storage section according to a third embodiment of the present invention. It is a block diagram of another example of the 3rd Embodiment of this invention. FIG. 7 is a configuration diagram showing a capacitor in a capacitor storage section according to a fourth embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings.

(Configuration of in-wheel inverter device and first embodiment)
A first embodiment of the present invention will be described using FIGS. 1 to 5. FIG. 1 is a perspective view showing the configuration of a wheel section including an in-wheel inverter device, and FIG. 2 is a sectional view of FIG. 1.

The wheel portion includes a wheel 1, a wheel fixing portion 2, a lower arm 3, a strut 4, a spring 5, and a connector 6. Furthermore, the inside of the wheel 1 includes an inverter 9, a shaft 10, a stator 8 serving as a motor, and a rotor 11. Inverter 9 is connected to motor 8 , power supply wiring 7 is electrically connected to connector 6 , and connector 6 is electrically connected to inverter 9 . The lower arm 3 and strut 4 are installed on the wheel fixing part 2.

FIG. 3 is a circuit diagram of the inverter 9. The inverter 9 is connected to a power module 31 that converts DC power supplied from a battery 30 mounted on a vehicle having the wheel portion of FIG. A capacitor 16 is connected to the power module 31 and smoothes the DC power input to the power module 31. The power module 31 is configured by, for example, a combination of an IGBT (Insulated Gate Bipolar Transistor) and a diode, or a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor). Although three capacitors 16 are arranged in parallel in FIG. 3, the number is not limited to this.

FIG. 4 is a diagram showing the location of the capacitor storage section 15 in the inverter 9 according to the first embodiment of the present invention.

The inverter 9 includes a power module storage section 14 that stores the power module 31 and a capacitor storage section 15 that stores the capacitor 16. In the capacitor storage section 15, a capacitor 16 is installed on a printed circuit board. The capacitor storage section 15 is arranged at a position between the shaft 10 and the ground 13, and the power module storage section 14 is arranged at a position farther from the ground 13 than the capacitor storage section 15. That is, the capacitor storage section 15 is arranged lower than the power module storage section 14 in the vertical direction of the wheel 1. Note that the capacitor storage section 15 and the power module storage section 14 are electrically connected by a bus bar (not shown) or the like.

Heat emitted from the power module housing section 14 is diffused toward the upper layer of the tire 12. As a result, the temperature of the lower layer of the tire 12, that is, the portion of the tire closer to the ground 13, is lower than that of the upper layer. Further, by installing the capacitor storage section 15 between the shaft 10 and the ground 13, the capacitor 16 can be protected from the heat emitted from the power module storage section 14.

FIG. 5 is a configuration diagram showing details of the arrangement of the capacitors 16 in the capacitor storage section 15. As shown in FIG. Further, FIG. 6 is a cross-sectional view taken along the line AA in FIG.

The capacitor 16 is installed on a printed circuit board formed by a printed circuit board base material 20 and a printed circuit board resist 21. The capacitor 16 also includes a capacitor pin 19 that penetrates the printed circuit board while electrically connecting to the printed circuit board wiring 22, an adhesive 17 that is applied around the bottom of the capacitor 16, and a capacitor 16 installed on the printed circuit board. It is fixed in a predetermined position on the printed circuit board by solder 23 that adheres to the capacitor pin 19 on the opposite surface. In FIG. 5, the capacitor pin 19 penetrates the printed circuit board in a portion that is not sandwiched between the two parallel capacitor electrodes 18 inside the capacitor 16.

Such a configuration reduces the stress on the solder 23 connected to the capacitor pin 19 due to vibration, that is, the stress on the solder caused by the vibration of the capacitor 16 in conjunction with the vibration applied to the wheel 1. Although the printed circuit board resist 21 is not provided directly under and around the capacitor 16 in FIG. 6, the resist 21 may be provided directly below the capacitor 16.

According to the first embodiment of the present invention described above, the following effects are achieved.

(1) The in-wheel inverter device includes an inverter 9 connected to the stator 8 and rotor 11 that serve as a motor, and the inverter 9 houses a power module storage part 14 that stores a power module and a capacitor 16. The capacitor storage section 15 includes a printed circuit board and a plurality of capacitor pins 19 that are solder-connected to the printed circuit board with solder 23 and penetrate the printed circuit board. The capacitor 16 is bonded to a printed circuit board using an adhesive 17, and is fixed to the printed circuit board via a plurality of capacitor pins 19. By doing this, the reliability of the capacitor in the in-wheel inverter device can be ensured.

(2) The capacitor storage section 15 of the in-wheel inverter device is arranged lower than the power module storage section 14 in the vertical direction of the inverter 9 when the in-wheel inverter device is mounted on the wheel portion of the vehicle. It is characterized by By doing this, it is possible to reduce the influence of heat radiation from the power module. Furthermore, according to experiments conducted by us, it has become clear that the adhesion strength between the printed circuit board resist and the adhesive is much worse than that with the printed circuit board base material 20. Therefore, it is better to bond the capacitor 16 and the printed circuit board to the printed circuit board base material 20.

(Second embodiment)
FIG. 7 is a configuration diagram showing the capacitor 16 of the capacitor storage section 15 according to the second embodiment of the present invention.

The capacitor 16 has a rectangular shape that is vertically elongated in the vertical direction, and the long sides of the capacitor 16 are perpendicular to the ground. Further, the capacitor pin 19 passes through the capacitor 16 at a position closer to the center than the upper and lower ends of the wheel 1 in the height direction. By doing so, the vertically elongated shape of the capacitor 16 absorbs vibrations from the ground in the vertical direction, and the stress generated on the solder 23 in FIG. 6 connected to the capacitor pin 19 can be reduced.

Furthermore, since stress generated during vibration in the vertical direction is likely to occur near the adhesive 17, by moving the capacitor pin 19 away from the adhesive 17, the stress generated in the solder 23 can be similarly reduced. Note that the shape of the capacitor 16 is not limited to a vertically long rectangular shape, but can also be applied to a square shape, for example.

According to the second embodiment of the present invention described above, the following effects are achieved.

(3) The capacitor 16 of the in-wheel inverter device has a rectangular shape, and the long sides of the capacitor 16 are perpendicular to the ground. By doing this, it is possible to reduce the stress generated by vibration in the vertical direction.

(Third embodiment)
8 and 9 are configuration diagrams showing a capacitor in a capacitor housing according to a third embodiment of the present invention.

In FIG. 8, a plurality of bolt fixing parts 24 are provided on opposite sides of the capacitor 16 for fixing the capacitor 16 to the printed circuit board. On the other hand, in FIG. 9, a plurality of bolt fixing parts 24 are provided on diagonal corners of the capacitor 16. Bolts passing through the printed circuit board are attached to the bolt fixing parts 24, respectively. Although not shown, the printed circuit board is fixed to the wheel fixing part 2 via this bolt. That is, the capacitor 16 shown in FIGS. 8 and 9 is fixed to the printed circuit board and also to the wheel fixing part 2 at the same time.

By fixing the printed circuit board in the capacitor accommodating portion 15 with bolts in FIGS. 8 and 9, vibration of the capacitor 16 can be suppressed, and stress generated in the solder 23 connected to the capacitor pin 19 can be further reduced.

According to the third embodiment of the present invention described above, the following effects are achieved.

(4) The in-wheel inverter device includes a plurality of bolts that are arranged on opposite sides or diagonal corners of the capacitor 16 and penetrate through the printed circuit board. The printed circuit board is characterized in that it is fixed to the wheel fixing section 2 of the wheel section via the plurality of bolts. By doing this, the stress generated on the solder 23 can be reduced.

(Fourth embodiment)
FIG. 10 is a configuration diagram showing a capacitor in a capacitor storage section according to a fourth embodiment of the present invention.

FIG. 10 shows a configuration in which a larger number of capacitor pins 19 are arranged than in the first to third embodiments. This capacitor pin 19 is, for example, a dummy pin that does not electrically connect the capacitor 16 and the printed circuit board. By using dummy pins that are not electrically connected, it is possible to achieve stability with less electrical change than simply increasing the number of capacitor pins 19 that have electrical connections, and also to stabilize the capacitor 16 in response to vibrations applied to the wheel 1. It is possible to reduce the stress generated on the solder 23 due to vibrations.

According to the fourth embodiment of the present invention described above, the following effects are achieved.

(5) At least one of the plurality of capacitor pins 19 of the in-wheel inverter device is a dummy pin that does not form an electrical connection between the capacitor 16 and the printed circuit board. By doing this, the stress generated on the solder 23 can be reduced in an electrically stable state.

Each of the embodiments described above is merely an example, and the present invention is not limited to these contents as long as the characteristics of the invention are not impaired. Further, other embodiments that can be considered within the scope of the technical idea of the present invention are also included within the scope of the present invention.

1... Wheel 2... Wheel fixing part 3... Lower arm 4... Strad 5... Spring 6... Connector 7... Power supply wiring 8... Stator 9... Inverter 10... Shaft 11... Rotor 12... Tire 13... Ground 14... Power module storage part 15... Capacitor storage section 16...Capacitor 17...Adhesive material 18...Capacitor electrode 19...Capacitor pin 20...Printed board base material 21...Printed board resist 22...Printed board wiring 23...Solder 24...Bolt fixing part 30...Battery 31...Power module

Claims (4)

An in-wheel inverter device that includes an inverter connected to a motor,
The inverter is
a power module storage section that stores a power module for converting DC power to AC power;
a capacitor storage section that stores a capacitor for smoothing the DC power,
The capacitor storage section includes a printed circuit board and a plurality of capacitor pins that are solder-connected to the printed circuit board and pass through the printed circuit board, and when the in-wheel inverter device is mounted on a wheel portion of a vehicle, arranged lower than the power module storage section in the vertical direction of the inverter,
The in-wheel inverter device is characterized in that the capacitor is bonded to the printed circuit board using an adhesive and fixed to the printed circuit board via the plurality of capacitor pins. In the in-wheel inverter device according to claim 1 ,
The capacitor has a rectangular shape,
An in-wheel inverter device, wherein the long side of the capacitor is perpendicular to the ground. In the in-wheel inverter device according to claim 1 ,
A plurality of bolts are arranged on opposite sides or diagonal corners of the capacitor and pass through the printed circuit board,
The in-wheel inverter device is characterized in that the printed circuit board is fixed to the wheel portion via the plurality of bolts. In the in-wheel inverter device according to claim 1 ,
An in-wheel inverter device, wherein at least one of the plurality of capacitor pins is a dummy pin that does not form an electrical connection between the capacitor and the printed circuit board.

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