vehicle

Abstract

To provide a vehicle which can restrain beat sound flexibly according to running state.SOLUTION: A vehicle comprises drive parts 25, 26 which drive different two wheels 11,12 by respective motors 21, 22, inverters 31, 32 which electrically supply to the motors 21, 22 of the respective drive parts 25, 26 and a control part 35 which controls the inverters 31,32. The control part 35 variably controls carrier frequencies CFL, CFR in the drive parts 25, 26 by controlling the inverters 31,32 so that frequency differences X of noise vibration NVL, NVR caused by the respective drive parts 25, 26 is out of beat sound generation range A-B in which the beat sound is generated by synthesis of the noise vibration NVL, NVR.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a vehicle. [Background technology]

[0002] Patent Document 1 discloses a technology for a vehicle having in-wheel motors equipped with a motor and a reduction mechanism for each wheel, in which the combination of the number of teeth in the reduction mechanism is made different between at least one combination of in-wheel motors, thereby suppressing humming noise caused by interference between sounds generated by the reduction mechanisms and motors of each in-wheel motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2008-37133 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a vehicle is running, a humming noise occurs depending on the driving conditions. For this reason, the technology described in Patent Document 1, which suppresses humming noise of a specific frequency by changing the combination of the number of teeth of the reduction gear mechanism, may have difficulty in sufficiently suppressing the humming noise that occurs depending on the driving conditions.

[0005] The present invention has been made in consideration of the above circumstances, and has an object to provide a vehicle that can flexibly suppress roar noise depending on the driving conditions. [Means for solving the problem]

[0006] In order to achieve the above object, the vehicle of the present invention comprises: A drive unit that drives two different wheels by motors, an inverter that supplies power to the motor of each of the drive units; A control unit that controls the inverter; Equipped with The control unit controls the inverter to variably control the carrier frequency in the drive unit so that the frequency difference between the noise vibrations generated in each drive unit falls outside the beat sound generation range in which a beat sound is generated by the synthesis of the noise vibrations.

[0007] With a vehicle having this configuration, the inverter that supplies power to the motors of each wheel is controlled to variably control the carrier frequency in the drive unit, thereby making it possible to flexibly suppress the humming noise according to the driving conditions. Also, compared to changing the combination of gears in the reduction mechanism to suppress the humming noise, it is possible to suppress increases in cost and weight. Effect of the Invention

[0008] According to the present invention, a vehicle can be provided that can flexibly suppress roar noise depending on the driving conditions. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a vehicle according to this embodiment. [Diagram 2] FIG. 2 is a graph showing noise vibrations in the drive units of the left and right wheels. [Diagram 3] FIG. 3 is a flowchart illustrating the control by the control unit. [Figure 4] FIG. 4 is a graph showing noise vibrations in the drive parts of the left and right wheels, illustrating the suppression of the generation of the roaring noise by the control part. [Diagram 5] FIG. 5 is a graph showing noise vibrations in the drive parts of the left and right wheels when traveling straight. [Figure 6] FIG. 6 is a graph showing noise vibrations in the drive parts of the left and right wheels when turning. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic configuration diagram of a vehicle 1 according to this embodiment.

[0011] As shown in Fig. 1, the vehicle 1 according to this embodiment has two wheels 11, 12 at the front, which serve as front wheels, and two wheels 13, 14 at the rear, which serve as rear wheels. The vehicle 1 is a front-wheel drive vehicle in which the front wheels 11, 12 are drive wheels. Note that the front-wheel drive vehicle 1 is just one example, and the vehicle may be a rear-wheel drive vehicle in which the rear wheels 13, 14 are drive wheels, or an all-wheel drive vehicle in which all the wheels 11 to 14 are drive wheels.

[0012] The wheels 11, 12, which are drive wheels of the vehicle 1, have motors 21, 22, respectively, and the driving force of the motors 21, 22 is transmitted to the wheels 11, 12. In this manner, the vehicle 1 is provided with drive units 25, 26 that drive the wheels 11, 12 by the motors 21, 22. The motors 21, 22 of the drive units 25, 26 are supplied with power from inverters 31, 32, respectively. These inverters 31, 32 are connected to and controlled by a control unit 35. The carrier frequency of each of the inverters 31, 32 is variable. In the vehicle 1, the motors 21, 22 of the drive units 25, 26 are driven by power supplied from the inverters 31, 32 controlled by the control unit 35, whereby the wheels 11, 12 are rotated and driven to run.

[0013] In the vehicle 1 equipped with the drive units 25, 26 having the motors 21, 22 that rotate the wheels 11, 12, respectively, noise vibrations NV are generated during power conversion in the inverters 31, 32 of the drive units 25, 26.

[0014] FIG. 2 is a graph showing noise vibrations NVL and NVR in the drive parts 25 and 26 of the left and right wheels 11 and 12. In FIG. 2, for example, when turning the vehicle 1, the rotation speeds of the motors 21, 22 of the left and right wheels 11, 12 are made different. For example, when turning the vehicle 1 to the right, the rotation speed RR of the motor 22 of the right wheel 12 is lower than the rotation speed RL of the motor 21 of the left wheel 11. At this time, in the left and right drive units 25, 26 equipped with the inverters 31, 32 having carrier frequencies CFL, CFR, the frequency FL of the noise vibration NVL generated in the left drive unit 25 is lower than the frequency FR of the noise vibration NVR generated in the right drive unit 26.

[0015] When the frequency difference X, which is the difference between the frequency FR of the right noise vibration NVR and the frequency FL of the left noise vibration NVL, falls within a specific range, the beat sound generation range A to B, these noise vibrations NVL and NVR overlap to generate a beat sound, which is a beat noise. Note that if the frequency difference X is small and does not reach the beat sound generation range A to B, or if the frequency difference X is large and exceeds the beat sound generation range A to B, the beat sound caused by the overlap of these noise vibrations NVL and NVR will cease to be generated.

[0016] In the vehicle 1 according to this embodiment, in order to suppress the roaring noise, the control unit 35 controls the inverters 31, 32 as follows.

[0017] First, information on the tire diameter, wheel speed, and steering angle of the wheels 11, 12 is obtained (step S1).

[0018] Next, the turning radius of the vehicle 1 and the rotation speed of each of the wheels 11, 12 are calculated from the acquired information on the tire diameter, wheel speed and steering angle of the wheels 11, 12 (steps S2, S3).

[0019] Based on information on the tire diameter, wheel speed and steering angle of the wheels 11, 12, the turning radius of the vehicle 1 and the rotation speed of each wheel 11, 12, the frequencies FL, FR of the noise vibrations NVL, NVR in each drive section 25, 26 are calculated (step S4).

[0020] A frequency difference X, which is the difference between the frequencies FL and FR of the calculated noise vibrations NL and NR, is calculated (step S5).

[0021] It is determined whether or not the frequency difference X is within a beat noise generation range A to B (A≦X≦B) (step S6).

[0022] When it is determined that the frequency difference X is within the beat sound generation range A to B (step S6: Yes), at least one of the inverters 31, 32 of the drive units 25, 26 is controlled to change at least one of the carrier frequencies CFL, CFR so that the frequency difference X falls outside the beat sound generation range A to B (step S7).

[0023] FIG. 4 is a graph showing noise vibrations NVL and NVR in the drive parts 25 and 26 of the left and right wheels 11 and 12, illustrating the suppression of the generation of the roaring noise by the control part 35. In FIG. 4, when the vehicle 1 turns right, for example, the carrier frequency CFR of the inverter 32 of the right drive unit 26 is lowered. Then, the frequency FR of the noise vibration NVR generated in the right drive unit 26 decreases, the frequency difference X decreases or disappears, and the frequency falls outside the beat noise generation range A to B. This suppresses the generation of beat noise caused by the overlap of the noise vibrations NVL and NVR.

[0024] Note that the frequency difference X between the frequencies FL, FR of the noise vibrations NVL, NVR in the left and right drive parts 25, 26 due to changes in the carrier frequencies CFL, CFR may be increased to fall outside the beat sound generation range A-B.

[0025] As described above, according to the vehicle 1 of this embodiment, the humming noise can be flexibly suppressed according to the running state by controlling the inverters 31, 32 that supply power to the motors 21, 22 of the wheels 11, 12 to variably control the carrier frequencies CFL, CFR in the drive units 25, 26. Furthermore, compared to changing the combination of gears in the reduction gear mechanism to suppress the humming noise, it is possible to suppress increases in cost and weight.

[0026] Here, Figure 5 shows the noise vibrations NVL, NVR in the drive parts 25, 26 of the left and right wheels 11, 12 when the vehicle 1 is moving straight, and Figure 6 shows the noise vibrations NVL, NVR in the drive parts 25, 26 of the left and right wheels 11, 12 when the vehicle 1 is turning.

[0027] As shown in Figs. 5 and 6, the frequency difference X between the drive units 25, 26 of the wheels 11, 12 in possible driving states may be calculated in advance from the specifications of the vehicle 1, and the inverters 31, 32 may be controlled to intentionally shift the carrier frequencies FL, FR so that the frequency difference X between the drive units 25, 26 of the wheels 11, 12 does not fall within the beat noise generation range A to B in which beat noise is generated.

[0028] In the above embodiment, an example has been given of the application to the drive units 25, 26 of the left and right wheels 11, 12 of a vehicle 1, but the present invention may also be applied to the front and rear drive units of a vehicle equipped with drive units in which the front and rear wheels are driven by a motor controlled by an inverter. [Explanation of symbols]

[0029] 1 vehicle 11,12 wheels 31,32 Motor 25,26 Drive unit 31,32 Inverter 35 Control section A~B Beat noise generation range CFL, CFR carrier frequency NVL, NVR Noise Vibration X Frequency Difference

Claims

[Claim 1] A drive unit that drives two different wheels by motors, respectively; an inverter that supplies power to the motor of each of the drive units; A control unit that controls the inverter; Equipped with The control unit controls the inverter to variably control a carrier frequency in the drive unit so that a frequency difference between the noise vibrations generated in each of the drive units falls outside a beat sound generation range in which a beat sound is generated by synthesis of the noise vibrations. vehicle.

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