Electric vehicle

Abstract

To provide a technology for eliminating sense of incongruity of a driver caused by vibration and sound of an electric vehicle.SOLUTION: An electric vehicle includes: a vibration generation unit mounted on a vehicle body via a vibration damping member; and a vibration transmission path from the vibration generation unit to the vehicle body without passing through the vibration damping member.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to electric vehicles.

Background Art

[0002] Patent Document 1 discloses a vehicle that is driven by using the rotational force output from a motor as power. The vehicle includes a motor that outputs rotational power, a speed reduction mechanism unit that transmits the rotational power of the motor to drive wheels, and a vibration component that generates vibration. The motor and the speed reduction mechanism unit are connected to form a drive device unit, and the vibration component is attached to the drive device unit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, in an automobile, the smaller the vibration transmission, the more preferable it is. The smaller the vibration transmission, the more the sound caused by vibration can be suppressed. Electric vehicles are superior in quietness compared to engine vehicles, but electric vehicles also have problems related to sounds such as high-frequency motor sounds, road noise, and wind noise. There is a concern that these sounds are recognized as a discomfort by the driver.

[0005] One object of the present disclosure is to provide a technique for eliminating the discomfort of the driver caused by vibrations and sounds in an electric vehicle.

Means for Solving the Problems

[0006] The viewpoint of the present disclosure relates to electric vehicles. An electric vehicle includes a vibration generating part mounted on a vehicle body via a vibration damping member, and A vibration transmission path from a vibration generating part to a vehicle body without passing through a vibration damping member and is provided.

Advantages of the Invention

[0007] According to the aspect of the present disclosure, an electric vehicle is provided with a vibration transmission path that does not pass through a vibration damping member. As a result, an appropriate level of vibration is transmitted to the vehicle body. By the appropriate level of vibration being perceived by the driver as sound with an appropriate sound pressure and frequency, it is expected to eliminate the discomfort related to the vibration and sound of the electric vehicle.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0010] 1. Vibration of an Electric Vehicle FIG. 1 is a schematic diagram of an electric vehicle 1. Examples of the electric vehicle 1 include various vehicles such as BEV, PEV, and HEV. In the figure, the x-axis direction corresponds to the front direction of the electric vehicle 1. The y-axis direction corresponds to the left direction from the driver's viewpoint of the electric vehicle 1, and the z-axis direction corresponds to the upward direction of the electric vehicle 1.

[0011] The power train (the group of components necessary to rotate the drive wheels) of the electric vehicle 1 is composed of a battery that charges and discharges electric power, an inverter that controls the electric power, a motor that converts the electric power into rotational force, and the like.

[0012] The direct current supplied from the battery is converted into alternating current by the inverter. The alternating current is necessary to rotate the motor. The group of components constituting the power train mentioned here generates vibration during operation. The vibration is transmitted through the air and the vehicle body and is perceived as sound by the driver and passengers of the electric vehicle 1.

[0013] The integrated unit of the inverter, motor, etc. is called an e-axle. Generally, the e-axle is mounted on a vehicle as an off-the-shelf product. The e-axle integrating the group of components that generate vibration also generates vibration. The electric vehicle 1 is provided with a vibration generating part 20 such as an e-axle. In the present embodiment, the vibration generating part 20 is described as an e-axle. Note that the vibration generating part 20 is not limited to an e-axle as long as it is a component that generates vibration. For example, an air conditioner compressor also corresponds to the vibration generating part 20.

[0014] FIG. 2 is a schematic diagram showing the positional relationship between the vehicle body 10 and the vibration generating part 20.

[0015] The vibration generating part 20 is mounted on the vehicle body 10 via a vibration damping member 40 that attenuates vibration. The vibration damping member 40 is an elastic body such as rubber. The vibration generating part 20 is an e-axle. The electric vehicle 1 further includes a mounting bracket 50 that connects the vibration generating part 20 and the vibration damping member 40. The mounting bracket 50 is typically made of metal and is mechanically joined to the vibration generating part 20 by bolts, nuts, etc. Also, the mounting bracket 50 is fixed to the vehicle body 10 so as to sandwich the vibration damping member 40 by bolts, nuts, etc. In the figure, the vehicle body 10 is depicted as a vehicle frame.

[0016] The electric vehicle 1 is provided with a vibration transmission path 30. Here, the vibration transmission path 30 is composed of a solid, not an air layer. For example, the vibration transmission path 30 includes a vibration transmission bracket 34. The vibration transmission bracket 34 connects the mount bracket 50 and the vehicle body 10. That is, the vibration transmission path 30 extends from the vibration generating part 20 to the vehicle body 10 via the mount bracket 50 and the vibration transmission bracket 34. The vibration transmission bracket 34 is made of a metal plate and is fixed to the mount bracket 50 and the vehicle body 10 by mechanical joining such as bolts and nuts.

[0017] The vibration generated in the vibration generating part 20 is divided into a path via the mount bracket 50 and the vibration damping member 40 and a vibration transmission path 30 that does not pass through the vibration damping member 40 and is transmitted to the vehicle body 10. When transmitted to the vehicle body 10 via the vibration damping member 40, the vibration is transmitted to the vehicle body 10 through the vibration damping member 40, so the vibration level attenuates before the vibration is transmitted to the vehicle body 10. On the other hand, the vibration transmitted to the vehicle body 10 through the vibration transmission path 30 is transmitted via the mount bracket 50 and the vibration transmission bracket 34 (without passing through the vibration damping member 40). Therefore, the degree of attenuation of the vibration level transmitted to the vehicle body 10 is smaller compared to the case of passing through the vibration damping member 40.

[0018] 2. Problems and Effects Generally, the smaller the vibration transmission of a vehicle, the more preferable it is. The smaller the vibration transmission, the more the sound caused by vibration can be suppressed. Also, since a motor generates less vibration and sound compared to an engine, an electric vehicle is superior in quietness compared to a gasoline-powered vehicle. However, there are still issues related to vibration and the sound caused by vibration in electric vehicles. For example, the high-frequency sound generated from the magnetic material in the motor according to the switching frequency of the inverter is a problem unique to electric vehicles. There are also issues due to the quietness of electric vehicles. For example, sounds that were not a concern in gasoline-powered vehicles, such as road noise generated when the tires roll on the road surface and wind noise caused by the vehicle cutting through the air, become prominent due to the quietness of electric vehicles. These sounds may cause concerns that are recognized as a sense of discomfort when a driver who has been driving a gasoline-powered vehicle switches to an electric vehicle.

[0019] Therefore, in the present disclosure, in order to solve the problems (the driver's sense of discomfort) caused by the vibration and sound of the electric vehicle 1, a vibration transmission path 30 that does not pass through the vibration damping member 40 is deliberately introduced. As a result, an appropriate level of vibration is transmitted to the vehicle body 10. The appropriate level of vibration is perceived by the driver as sound with an appropriate sound pressure and frequency, and it is expected to eliminate the sense of discomfort related to the vibration and sound of the electric vehicle 1. Also, by appropriately changing the material, dimensions, arrangement, etc. of the vibration transmission bracket 34, it is possible to adjust the resonance frequency and the frequency characteristics of the audible sound.

[0020] Also, when the vibration generating unit 20 includes a motor that drives the electric vehicle 1, the magnitude and frequency of the vibration caused by the motor change in conjunction with the rotational speed of the motor, that is, the speed of the electric vehicle 1. Therefore, the sound pressure and frequency of the sound generated due to the vibration transmitted to the vehicle body 10 via the vibration damping member 40 also change in conjunction with the speed of the electric vehicle 1. Thus, the sound pressure and frequency of the sound perceived by the driver change in conjunction with the speed of the electric vehicle 1, that is, in conjunction with the accelerator operation by the driver. As a result, the driver can obtain a feeling as if driving a gasoline-powered vehicle.

[0021] The electric vehicle 1 may be provided with an "MT mode" capable of pseudo-reproducing the manual shifting operation and driving characteristics of a manual transmission vehicle (MT vehicle) (see, for example, Japanese Patent No. 6787507). In that case, the electric vehicle 1 is provided with a pseudo-operation member (e.g., a pseudo-shifting device, a pseudo-clutch pedal) for pseudo-reproducing the manual shifting operation of the MT vehicle. In the MT mode, the driver of the electric vehicle 1 can drive the electric vehicle 1 by operating the pseudo-operation member as if driving an MT vehicle. Further, the sound caused by the vibration generating unit 20 and the vibration transmission path 30 changes in conjunction with the accelerator operation by the driver. Since the sound is also pseudo-reproduced together with the driving operation of the MT vehicle, the feeling that the driver is driving an MT vehicle is further enhanced.

[0022] 3. Modified Example 3-1. Modified Example of Vibration Transmission Path FIG. 3 is a schematic diagram showing a modified example of the vibration transmission path 30. The vibration transmission path 30 includes a vibration transmission member 33, a first connection member 31, and a second connection member 32. The first connection member 31 connects the vibration transmission member 33 and the vibration generating unit 20. The second connection member 32 connects the vibration transmission member 33 and the vehicle body 10 (vehicle frame). The vibration generated in the vibration generating unit 20 is transmitted to the vehicle body 10 through the first connection member 31, the vibration transmission member 33, and the second connection member 32.

[0023] Here, it is assumed that a wire harness (automotive multi-core electric wire) is used as the vibration transmission member 33. The wire harness connects electrical and electronic devices mounted on the vehicle. In particular, in an electric vehicle powered by a motor, it can be said that a high-voltage wire harness for supplying a high voltage from the battery to the motor is essential. The first connection member and the second connection member are metal parts and are mechanically joined to the connection targets by bolts, nuts, etc. Similar to the example of FIG. 2, the vibration and sound can be adjusted by changing the dimensions, materials, and connection positions of the respective parts.

[0024] FIG. 4 is a schematic diagram showing another modification of the vibration transmission path 30. Here too, as in the example of FIG. 3, a vibration transmission member 33 (wire harness), a first connection member, and a second connection member are used. The difference from the example of FIG. 3 is that the second connection member connects the vibration transmission member 33 and the body (sheet metal part). For example, by attaching the second connection member 32 near the driver's seat, vibration and sound can be transmitted to the driver more directly. It should be noted that it is also possible to use the vibration transmission bracket 34 shown in FIG. 2 and the vibration transmission member 33 shown in FIGS. 3 and 4 in combination.

[0025] 3-2. Switching of Vibration Transmission Path If the ON / OFF function of the vibration transmission path 30 can be switched, the driver can more flexibly customize the sound and vibration environment of the electric vehicle 1.

[0026] FIG. 5 is a schematic diagram for explaining the switching part 60 in the vibration transmission path 30. The vibration transmission path 30 is divided into a first part 30A and a second part 30B. The first part 30A and the second part 30B are not in contact with each other. Also, a connecting member 61 having a T-shaped cross-section is installed near two coils 62. The connecting member 61 is a magnetic body and a movable body that moves according to the current flowing through the coil 62. The current flowing through the coil 62 is controlled. (A) in FIG. 5 shows a state (first state) where the control signal is OFF. At this time, the connecting member 61 is not in contact with either the first part 30A or the second part 30B. On the other hand, (B) in FIG. 5 shows a state (second state) where the control signal is ON. At this time, the connecting member 61 is in contact with the first part 30A and the second part 30B. That is, in the first state, since the vibration transmission path 30 remains disconnected, vibration is not transmitted, but in the second state, vibration can be transmitted because the vibration transmission path 30 is connected via the connecting member 61. The method of realizing the switching part 60 is not limited to the method using the coil 62 and the magnetic body (connecting member 61). For example, it may be a mode in which the first state and the second state are switched by a mechanical switch.

[0027] The configuration when the switching unit 60 is introduced into the embodiments described so far will be described. In the example of FIG. 2, the vibration transmission bracket 34 may be divided and the connecting member 61 and the coil 62 may be installed. In the cases of the examples of FIGS. 3 and 4, a wire harness is used as the vibration transmission member 33, and the wire harness cannot be divided due to its function. Therefore, it is desirable to adopt a configuration in which the first connecting member 31 or the second connecting member 32 is divided.

[0028] 4. Application possibilities So far, as the vibration generating unit 20, an essential part (e-axle) for driving the electric vehicle 1 has been described as an example. However, as a further application example, a configuration in which an electrically controlled vibration generating unit 20 is provided for the purpose of applying vibration to the vehicle body 10 is also conceivable. For example, as the vibration generating unit 20, a vibrator 70 is attached to the body, and by controlling the vibrator 70 in cooperation with the operation input of the driver, it is possible to reproduce the vibration accompanying acceleration.

[0029] The above-described configuration is particularly effective when the electric vehicle 1 is provided with the MT mode mentioned in Section 2. FIG. 6 is a schematic diagram showing a configuration example in which a vibrator 70 is installed on the body of the electric vehicle 1 having the MT mode. In this case, in the electric vehicle 1, the virtual engine speed Ne and the virtual engine output torque Teout are calculated according to the operation input such as the accelerator opening Pap. By controlling the vibrator 70 in cooperation with the virtual engine speed Ne and the virtual engine output torque Teout, the electric vehicle 1 can reproduce not only the driving characteristics of a general MT vehicle but also the vibration accompanying acceleration and deceleration. Therefore, the driver of the electric vehicle 1 equipped with the vibrator 70 feels the charm in the reproduction of a more realistic MT vehicle. Therefore, the vibrator 70 controlled according to the operation input can be mounted on the electric vehicle 1 having the MT mode, and a synergistic effect can be expected.

Explanation of reference numerals

[0030] 1: Electric vehicle, 10: Vehicle body, 20: Vibration generating section, 30: Vibration transmission path, 33: Vibration transmission member, 34: Vibration transmission bracket, 40: Vibration damping member, 50: Mounting bracket, 61: Connecting member, 70: Vibrator

Claims

1. a vibration generating part mounted on a vehicle body via a vibration damping member, and a vibration transmission path from the vibration generating part to the vehicle body without passing through the vibration damping member comprising an electric vehicle.

2. The electric vehicle according to Claim 1, comprising a mounting bracket connecting the vibration generating part and the vibration damping member, wherein the vibration transmission path connects the mounting bracket and the vehicle body an electric vehicle.

3. The electric vehicle according to Claim 1, wherein the vibration transmission path includes a vibration transmission member, a first connecting member, and a second connecting member, the first connecting member connecting the vibration transmission member and the vibration generating part, and the second connecting member connecting the vibration transmission member and the vehicle body an electric vehicle.

4. The electric vehicle according to Claim 1, wherein the vibration transmission path has a first part and a second part that do not contact each other, and a movable connecting member, in a first state, the connecting member does not contact the first part and the second part, and in a second state, the connecting member contacts the first part and the second part an electric vehicle.

5. The electric vehicle according to any one of Claims 1 to 4, wherein the vibration generating part includes a motor for driving the electric vehicle an electric vehicle.

Images