ELECTRIC VEHICLE

Abstract

An electric vehicle (1) includes a vibration generator (20) mounted on a vehicle body (10) via a vibration damping member (40). The electric vehicle (1) also includes a vibration transmission path (30) extending from the vibration generator (20) to the vehicle body (10) without passing through the vibration damping member (40). The vibrations generated in the vibration generator (20) are transmitted to the vehicle body (10) at a moderate intensity. This allows the driver to comfortably experience the vibration and noise. The driver's discomfort caused by the vibration and noise of the electric vehicle (1) can be alleviated.

Description

TECNIC FIELDThe present disclosure relates to electric vehicles.PRIOR ARTPatent Literature 1 discloses a vehicle driven by the rotational force output from a motor. The vehicle includes a motor that outputs a rotational force, a reduction gear that transmits the rotational force of the motor to driving wheels, and a vibration component that generates vibrations. The motor and the reduction gear are connected to a driving device, and the vibration component is attached to the driving device.Related Art ListPatent Literature 1: Japanese Patent Application No. 2020-114717SUMMARYIn general, it is desirable that the transmission of vibrations in vehicles is as low as possible. Since the transmission of vibration is less, the noise caused by the vibrations can be suppressed. Electric vehicles are superior to engines in puncto quietness, but electric vehicles also have problems with sounds such as high frequency motor sounds, road noise, wind sounds, etc. Car drivers may feel uncomfortable to this type of sound.An object of the present disclosure is to provide a technique for eliminating the driver's discomfort caused by vibrations and noises of electric vehicles.A first aspect relates to an electric vehicle.The electric vehicle includes:a vibration generator mounted on a vehicle body via a vibration damping member; anda vibration transmission path extending from the vibration generator to the vehicle body without traversing the vibration damping member.According to the aspect of the present disclosure, the electric vehicle includes the vibration transmission path that does not pass through the vibration damping member. In this way, moderate level vibration is transmitted to the vehicle body. This allows the driver to perceive the vibration of the moderate level as sound with moderate sound pressure and frequency. In this way, the discomfort of the driver caused by the vibration and noise of the electric vehicle can be alleviated.BRIEF DESCRIPTION OF DRAWINGSFIG. 1 is a schematic diagram of an electric vehicle; FIG. 2 is a schematic diagram showing a positional relationship between a vehicle body and a vibration generator; FIG. 3 is a schematic diagram showing a modification of a vibration transmission path; FIG. 4 is a schematic diagram showing another modification of the vibration transmission path; FIG. 5 is a schematic diagram for explaining a switching part in the vibration transmission path; FIG. 6 is a schematic diagram showing a configuration in which a shaker is installed on the body of the MT mode electric vehicle.DETAILED DESCRIPTIONEmbodiments of the present disclosure will be described with reference to the drawings.1. VIBRATION OF ELECTRIC VEHICLEFIG. 1 is a schematic diagram of an electric vehicle 1. examples of the electric vehicle 1 are various types of vehicles such as a BEV, a PEV, and an HEV. The x-axis direction in the drawing corresponds to the forward direction of the electric vehicle 1. the y-axis direction corresponds to the leftward direction as viewed by the driver of the electric vehicle 1, and the z-axis direction corresponds to the upward direction of the electric vehicle 1.The powertrain (components required for rotating the drive wheels) of the electric vehicle 1 includes a battery that charges and discharges the current, an inverter that controls the current, a motor that converts the current into a rotational force, and so on.The inverter converts a direct current supplied from the battery into an alternating current. The alternating current is needed to rotate the motor. These components of the powertrain generate vibrations when activated. The vibration is transmitted through the air or the vehicle body and perceived as sound by the driver or passenger of the electric vehicle 1.An integrated unit of inverter, motor, etc. is referred to as an E-axis. Generally, E-axles are mounted on a vehicle as a finished product. E-axes incorporating the vibration generating parts also generate vibrations. The electric vehicle 1 includes a vibration generator 20 such as an E-axis. In the present exemplary embodiment, the vibration generator 20 is referred to as an E-axis. The vibration generator 20 is not limited to an E-axis as long as it generates vibrations. For example, a compressor for an air conditioner also corresponds to the vibration generator 20.FIG. 2 is a schematic diagram showing a positional relationship between a vehicle body 10 and the vibration generator 20.The vibration generator 20 is mounted to the vehicle body 10 via a vibration damping member 40 for damping vibrations. The vibration damping member 40 is an elastic body made of, for example, rubber. The vibration generator 20 is, for example, an E-axis. The electric vehicle 1 further includes a mounting bracket 50 that connects the vibration generator 20 and the vibration damping member 40. The mounting bracket 50 is typically made of metal and is mechanically connected to the vibrator 20 by bolts, nuts, etc. The mounting bracket 50 is fixed to the vehicle body 10 with bolts, nuts, etc., so that the vibration damping member 40 is sandwiched between the mounting bracket 50 and the vehicle body 10. In the figure, the vehicle body 10 is shown as a vehicle frame.The electric vehicle 1 has a vibration transmission path 30. the vibration transmission path 30 is formed of a solid body, not an air layer. The vibration transmission path 30 includes, for example, a vibration transmission bracket 34. the vibration transmission bracket 34 connects the mounted mounting bracket 50 and the vehicle body 10. that is, the vibration transmission path 30 extends from the vibration generator 20 to the vehicle body 10 via the mounting bracket 50 and the vibration transmission bracket 34. the vibration transmission bracket 34 is made of, for example, a metal plate and is fixed to the mounting bracket 50 and the vehicle body 10 by a mechanical connection with bolts, nuts, etc.The vibration generated in the vibration generator 20 is transmitted to the vehicle body 10 by being divided into a path passing through the mounting bracket 50 and the vibration damping member 40 and the vibration transmission path 30 without passing through the vibration damping member 40. When the vibration is transmitted to the vehicle body 10 via the vibration damping member 40, which means that the vibration is transmitted to the vehicle body 10 via the vibration damping member 40, the vibration is attenuated in the transmission of the vibration to the vehicle body 10. On the other hand, the vibrations transmitted to the vehicle body 10 via the vibration transmission path 30 are transmitted via the mounting bracket 50 and the vibration transmission bracket 34 (without passing through the vibration damping member 40). Therefore, the vibration transmitted to the vehicle body 10 is less damped than in the case where the vibration is transmitted through the vibration damping member 40.2. PROBLEMS AND EFFECTSIn general, it is desirable that the vibration transmission of the vehicle is as low as possible, and the sound caused by the vibration can be suppressed because the vibration transmission is low. Since motors generate less vibration and noise than engines, electric vehicles are superior to motor vehicles in puncto quietness. However, even in electric vehicles, there are problems related to vibrations and noises caused by vibrations. A specific problem of electric vehicles is, for example, high frequency noise generated from a magnetic material in a motor depending on the switching frequency of an inverter. Another problem is the quietness of electric vehicles. For example, noise that is imperceptible to motor vehicles, such as road noise that arises when the tires roll on the roadway, or wind noise that arises when a vehicle is driven through the air, can be heard markedly due to the quietness of electric vehicles. These noises are unproblematic in motor vehicles, since engines generate louder noises. These noises can be perceived as unpleasant above all when a driver who previously driven a motor vehicle replaces the motor vehicle with an electric vehicle.Therefore, in the present disclosure, in order to solve the problem (driver's discomfort) caused by the vibration and the noise of the electric vehicle 1, the vibration transmission path 30 that does not pass through the vibration damping member 40 is installed. In this way, vibrations at a moderate level are transmitted to the vehicle body 10. The moderate level vibration is perceived by the driver as a noise having moderate sound pressure and frequency. This can alleviate the discomfort of the driver with respect to the vibration and noise of the electric vehicle 1. In addition, by changing the material, dimensions, arrangement, etc. of the vibration transmitting holder 34, the resonance frequency and frequency characteristic of the sound to be perceived can be adjusted.In addition, when the vibration generator 20 includes an engine that drives the electric vehicle 1, the magnitude and frequency of the vibration caused by the engine change depending on the rotational speed of the engine, i.e., the speed of the electric vehicle 1. Therefore, the sound pressure and frequency of the sound generated by the vibration transmitted to the vehicle body 10 via the vibration damping member 40 also change in association with the speed of the electric vehicle 1. Thereby, the driver feels as if he were driving a vehicle with an engine.The electric vehicle 1 may have an "MT mode" in which a manual shift operation and the travel characteristics of a manual transmission (MT) vehicle can be reproduced in a pseudo manner (see, for example, Japanese Patent No. 6787507). In this case, the electric vehicle 1 includes a pseudo operation element (e.g., a pseudo shift device or a pseudo clutch pedal) for pseudo-moderately reproducing the manual gear shift of the MT vehicle. In the MT mode, the driver of the electric vehicle 1 can drive the electric vehicle 1 as if he were driving an MT vehicle by operating the pseudo actuator. In addition, the sound caused by the vibration generator 20 and the vibration transmission path 30 changes in association with the accelerator operation by the driver. Since the noise is also pseudo-reproduced together with the running operation of the "imaginary" MT vehicle, the driver can feel more than if he were driving an MT vehicle.3. MODIFICATIONS3-1. Modifications of Vibration Transmission PathFIG. 3 is a schematic diagram showing a modification of the vibration transmission path 30. The vibration transmission path 30 includes a vibration transmission member 33, a first connector 31, and a second connector 32. the first connector 31 connects the vibration transmission member 33 and the vibration generator 20. the second connector 32 connects the vibration transmission member 33 and the vehicle body 10 (vehicle frame). The vibrations generated by the vibration generator 20 are transmitted to the vehicle body 10 via the first connector 31, the vibration transmission member 33, and the second connector 32.Here, it is assumed that a wire harness (wires or cables running in the vehicle) functions as the vibration transmission member 33. The wire harness connects electric / electronic devices mounted on a vehicle. In particular, an electric vehicle using a motor as a power source requires a high voltage wire harness to conduct a high voltage from a battery to the motor. The first connector 31 and the second connector 32 are metal parts and are mechanically connected to the connection target with bolts, nuts, etc. As shown in the example of FIG. 2, the vibration and the sound can be adjusted by changing the dimensions, the materials, and the connection positions of the individual components.FIG. 4 is a schematic diagram showing another modification of the vibration transmission path 30. Here, as shown in the example of FIG. 3, the vibration transmitting member 33 (wire harness), the first connector, and the second connector are used. The difference from FIG. 3, for example, is that the second connector 32 connects the vibration transmitting member 33 and the body (plate member). For example, by attaching the second connector 32 in the vicinity of the driver's seat, vibrations and noises can be more directly transmitted to the driver. The vibration transmission holder 34 shown in FIG. 2 and the vibration transmission member 33 shown in FIGS. 3 and 4 may also be used in combination.3-2. Switching of Vibration Transmission PathWhen the function of the vibration transmission path 30 can be turned on and off, the driver can more flexibly adjust the noise and vibration environment of the electric vehicle 1.FIG. 5 is a schematic diagram for explaining a switching unit 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. Near the two spools 62, a coupling member 61 having a T-shaped cross section is provided. The coupling member 61 is a magnetic body and a movable body that moves in accordance with a current flowing through the coils 62. The current flowing through the coils 62 is controlled, and part A of FIG. 5 shows a state in which the control signal is OFF (a first state). In this state, the clutch member 61 is not in contact with either the first part 30A or the second part 30B. On the other hand, the part B of FIG. 5 shows a state in which the control signal is ON (a second state). In this state, the clutch member 61 is in contact with both the first part 30A and the second part 30B. That is, in the first state, the vibration transmission path 30 is interrupted so that the vibration is not transmitted. However, in the second state, the vibration transmission path 30 is connected via the coupling member 61, so that the vibration can be transmitted. The method for realizing the switching unit 60 is not limited to the method including the coils 62 and the magnetic body (the coupling member 61). For example, another modification may be used in which the first state and the second state are switched by a mechanical switch.A configuration in which the switching unit 60 is inserted into the above-described embodiments will be described. In the example of FIG. 2, the vibration transmission holder 34 may be divided and the coupling member 61 and the spools 62 may be installed. In the example shown in FIGS. 3 and 4, the wire harness is used as the vibration transmitting member 33, and the wire harness cannot be divided to function properly. Therefore, it is desirable to adopt a configuration in which the first connector 31 or the second connector 32 is divided.4. FURTHER APPLICATIONThe vibration generator 20 is described as an essential component (E-axis) for driving the electric vehicle 1 in the above examples. However, as another application example, the vibration generator 20 may be a power train independent electrically controlled device installed to apply vibration to the vehicle body 10. As the vibration generator 20, for example, a shaker 70 is mounted on the body. When the shaker 70 is driven in cooperation with an operation input of the driver, the vibration caused by the acceleration can be simulated.The above-described configuration is particularly effective when the electric vehicle 1 has the MT mode mentioned in Section 2. FIG. 6 is a schematic diagram showing a configuration in which the shaker 70 is installed on the vehicle body of the electric vehicle 1 in the MT mode. In this case, in the electric vehicle 1, the virtual engine rotational speed Ne and the virtual engine output torque Teout are calculated in accordance with operation inputs such as an accelerator pedal position Pap. By controlling the shaker 70 in cooperation with the virtual engine rotational speed Ne and the virtual engine output torque Teout, the electric vehicle 1 can simulate not only the running characteristics of a general MT vehicle but also the vibrations associated with the acceleration and deceleration. Therefore, the driver of the electric vehicle 1 feels with the shaker 70 drawn towards a more realistic replica of an MT vehicle. Therefore, mounting the shaker 70 controlled according to the operation input to the electric vehicle 1 in the MT mode can produce a synergistic effect.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedJP 2020 - 114717

[0003] JP 6787507

[0021]

Claims

An electric vehicle (1) comprising: a vibration generator (20) mounted on a vehicle body (10) via a vibration damping member (40); and a vibration transmission path (30) extending from the vibration generator (20) to the vehicle body (10) without passing through the vibration damping member (40).The electric vehicle (1) according to claim 1, further comprising a mounting bracket (50) connecting the vibration generator (20) and the vibration damping member (40), wherein the vibration transmission path (30) connects the mounting bracket (50) and the vehicle body (10).The electric vehicle (1) according to claim 1, wherein the vibration transmission path (30) includes a vibration transmission member (33), a first connector (31), and a second connector (32), the first connector (31) connects the vibration transmission member (33) and the vibration generator (20), and the second connector (32) connects the vibration transmission member (33) and the vehicle body (10).The electric vehicle (1) according to claim 1, wherein the vibration transmission path (30) includes a first part (30A), a second part (30B), and a movable coupling member (61), the first part (30A) and the second part (30B) are not in contact with each other, the movable coupling member (61) is in contact with neither the first part (30A) nor the second part (30B) in a first state, and the movable coupling member (61) is in contact with both the first part (30A) and the second part (30B) in a second state.The electric vehicle (1) according to any one of claims 1 to 4, wherein the vibration generator (20) comprises a motor that drives the electric vehicle (1).

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