Sound source estimation method

Abstract

Provided is a sound source estimation method capable of analyzing abnormal sound generated from a vehicle with high precision and taking countermeasures for generation and regeneration of the abnormal sound. A sound source estimation method for a vehicle equipped with a drive motor acquires sound data of an abnormal sound generated from the vehicle, determines that the abnormal sound is caused by a thrust shake impact if a peak value (P2) exists in the sound data after a reverse timing (T) of a torque of the drive motor, and estimates a sound source generated from the vehicle if the peak value (P2) exists in the sound data. When there is no peak value (P2) in the sound data after the reverse timing (T) of the torque of the drive motor, it is determined that the abnormal sound is caused by the gear rattling impact.

Description

Technical Field

[0001] This invention relates to a method for sound source estimation. Background Technology

[0002] Patent document 1 discloses a method for extracting a potential sound source from the vehicle's driving information when an abnormal noise occurs, and reporting the measurement position corresponding to the potential sound source based on the relationship between the potential sound source and the measurement position of the sound source detection device.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-96554 Summary of the Invention

[0006] However, electric vehicles driven by the driving force of the drive motor are relatively quiet, so the shaking and impact noise in the drive unit that occurs during the reversal timing of the drive motor's rotation (chip in driving, chip out driving) is easily noticeable, and because the structure is relatively simple, it is also easy to determine the location of the shaking and impact noise.

[0007] However, these wobbling impact sounds include gear wobbling impact sounds generated between gears inside the drive unit, and thrust wobbling impact sounds generated when the bearings of gears that have shifted in the axial direction abut against the housing of the drive unit. Moreover, these wobbling impact sounds sometimes occur singly or continuously within a short period of time, making it difficult to determine which wobbling impact sound is dominant in order to take countermeasures or prevent its recurrence.

[0008] The present invention was made in view of the above circumstances, and its object is to provide a sound source inference method that can analyze abnormal noises from vehicles with high accuracy and take countermeasures for the occurrence and recurrence of abnormal noises.

[0009] To achieve the above objectives, the present invention provides a sound source estimation method, which is a sound source estimation method for a vehicle equipped with a drive motor, wherein...

[0010] Acquire sound data of abnormal noises generated by the vehicle.

[0011] If a peak in the sound data exists after the torque reversal timing of the drive motor, it is determined that the abnormal noise is caused by thrust-induced shaking impact.

[0012] If there is no peak in the sound data after the torque reversal timing of the drive motor, the abnormal noise is determined to be caused by gear shaking and impact.

[0013] Based on the sound source inference method of this structure, the source of abnormal noise is inferred from the peak value in the sound data of the abnormal noise and the timing of the torque reversal of the drive motor. Therefore, it is possible to analyze abnormal noises originating from relatively quiet electric vehicles with minimal background noise with high precision, and to take appropriate countermeasures for the occurrence and recurrence of the abnormal noise.

[0014] According to the present invention, a sound source inference method is provided that can analyze abnormal noises from vehicles with high accuracy, take measures to prevent the occurrence of abnormal noises, and take countermeasures to prevent their recurrence. Attached Figure Description

[0015] Figure 1 It is a schematic diagram of meshing gears that illustrates the principle of how gears vibrate and make impact noise.

[0016] Figure 2 It is a schematic diagram of interlocking gears illustrating the principle of the impact sound caused by thrust.

[0017] Figure 3 It is a graph showing the relationship between the torque of the drive motor, thrust displacement, and sound pressure.

[0018] Figure 4 This is a flowchart of the sound source estimation processing involved in this embodiment.

[0019] Figure 5 It is a diagram that illustrates the information of the units stored in the database.

[0020] Figure 6 It is a graphic illustrating overall processing. Detailed Implementation

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0022] Figure 1 It is a schematic diagram of meshing gears that illustrates the principle of how gears vibrate and make impact noise. Figure 2 It is a schematic diagram of interlocking gears illustrating the principle of the impact sound caused by thrust. Figure 3 It is a graph showing the relationship between the torque of the drive motor, thrust displacement, and sound pressure.

[0023] Electric vehicles are propelled by a drive motor (MG: Motor Generator, electric generator) located in the drive unit. Because electric vehicles are relatively quiet due to their inherent low noise levels, the rattling and impact noises occurring within the drive unit are easily noticeable. These rattling and impact noises generated in the drive unit mainly include gear rattling and impact noises and thrust rattling and impact noises. These noises occur as abnormal sounds, for example, during the timing of the reverse rotation of the drive motor (engagement driving, disengagement driving).

[0024] like Figure 1 As shown, the gear vibration and impact noise is generated by the contact between the teeth G1a of gear G1 on the drive motor side and the teeth G2a of gear G2 on the wheel side. Additionally, as... Figure 2 As shown, the impact sound from the thrust is transmitted through one of the two meshing gears G3 and G4 towards the shaft (thrust). Figure 2 The gear G3, which is displaced (in the direction of the middle arrow D), has its bearing B, which is located on the displaced side, abutting against the housing C of the drive unit.

[0025] Gear wobbling and impact noise occurs at the timing of the torque reversal of the drive motor, while thrust wobbling and impact noise occurs after the timing of the torque reversal of the drive motor. Therefore, as... Figure 3 As shown, in the drive unit, when gear wobbling impact noise and thrust wobbling impact noise are generated, the peak value P1 of gear wobbling impact noise is generated simultaneously with or before the reverse timing T of the torque of the drive motor, and the peak value P2 of thrust wobbling impact noise is generated after the reverse timing T of the torque of the drive motor.

[0026] However, among the abnormal noises from the vehicle, it is difficult to determine whether the gear rattling or thrust rattling noise is dominant.

[0027] Therefore, in this embodiment, by performing sound source estimation processing, the sound source is estimated with high precision by analyzing the abnormal noises generated by the vehicle. Hereinafter, according to... Figure 4 The flowchart illustrates the sound source inference processing.

[0028] Sound data is obtained by measuring the sound of the vehicle being tested while in motion using a measuring device (step S01). This sound data includes the sound of the vehicle being tested, including the impact sound caused by the accelerator being pressed or the impact sound caused by the accelerator being released.

[0029] Obtain the vehicle model information of the vehicle being tested (step S02). For example, a database stores vehicle model information for various vehicles, and the vehicle model information corresponding to the vehicle being tested is extracted from the database. This vehicle model information may include, for example, information about electric vehicles (BEV: Battery Electric Vehicle), internal combustion engine vehicles (ICEV: Internal Combustion Engine Vehicle), hybrid vehicles (HV: Hybrid Vehicle), etc.

[0030] Based on the vehicle model information of the vehicle being tested, determine whether the vehicle being tested is an electric vehicle (step S03).

[0031] Here, when the vehicle being tested is a vehicle other than an electric vehicle, such as a motor vehicle or a hybrid vehicle, the noise outside the drive unit with the drive motor is large, making it difficult to determine the location of the sound source. Therefore, in the determination of whether the vehicle being tested is an electric vehicle (step S03), if it is determined that the vehicle being tested is not an electric vehicle (step S03: "No"), it is considered that it is difficult to deduce the sound source in the vehicle being tested (step S04), and the sound source deduction process ends.

[0032] In determining whether the vehicle being tested is an electric vehicle (step S03), if the vehicle being tested is determined to be an electric vehicle (step S03: "Yes"), the torque of the drive motor is read in (step S05).

[0033] Applying sound data to the torque of the drive motor, compare the positive and negative reversal timing T of the drive motor torque with the peak values ​​P1 and P2 of the sound (refer to...). Figure 3 As a result, it is determined whether there is a sound peak P2 after the inversion time T (step S06).

[0034] In the determination of whether there is a sound peak P2 after the inversion timing T (step S06), if it is determined that there is no sound peak P2 after the inversion timing T (step S06: "No"), it is assumed that only gear shaking impact sound is generated in the drive unit (step S07), and the sound source speculation process ends.

[0035] In determining whether there is a sound peak P2 after the inversion timing T (step S06), if it is determined that there is a sound peak P2 after the inversion timing T (step S06: "Yes"), it is speculated that the sound peak P2 is a thrust shaking impact sound (step S08).

[0036] Obtain information related to the drive unit (step S09). For example, in the database, information on whether there is a thrust swaying impact is stored for each of various drive units, and the information of the drive unit mounted on the vehicle under test is extracted from the database.

[0037] Determine whether the drive unit mounted on the vehicle under test is a unit with thrust-induced shaking impact (step S10).

[0038] Here, Figure 5 It is a diagram that illustrates the information of the units stored in the database.

[0039] like Figure 5 As shown, the database stores, for example, information on whether or not there is thrust-induced shaking or impact in various units A, B, and C. Figure 4 The example shows a no-thrust swaying impact in units A and B (see reference). Figure 5(The "×" in the text) indicates that there is a thrusting impact in unit C (refer to...) Figure 5 If the "〇" in the figure is a drive unit C mounted on the vehicle being tested, it is determined to be a thrust-induced shaking impact.

[0040] In the determination of whether there is a thrust-induced swaying impact (step S10), if it is determined that there is no thrust-induced swaying impact in the drive unit mounted on the vehicle under test (step S10: "No"), it is considered that the abnormal noise occurring in the vehicle under test does not contain the thrust-induced swaying impact sound (step S11), and the sound source inference processing ends.

[0041] In determining whether there is a thrust-shaking impact (step S10), if it is determined that there is a thrust-shaking impact in the drive unit mounted on the vehicle under test (step S10: "Yes"), it is determined that the abnormal noise occurring in the vehicle under test includes a thrust-shaking impact sound (step S12).

[0042] An overall analysis (OA) process is performed on the gear rattling and thrust rattling impact sounds in the audio data. For each sound, the overall value is used for comparison and analysis to determine the sound level. In the overall analysis process, such as... Figure 6 As shown, the sum of sound pressure levels at all frequencies is calculated to obtain the overall (OA) value. Furthermore, it is determined whether the overall value of the thrust-induced vibration impact sound is greater than the overall value of the gear-induced vibration impact sound (step S13).

[0043] In the comparison and determination of the comprehensive value (step S13), if the comprehensive value of the gear shaking impact sound is greater than the comprehensive value of the thrust shaking impact sound, it is considered that the gear shaking impact sound is dominant among the abnormal noises generated in the vehicle being measured (step S14), and the sound source inference processing ends.

[0044] In the comparison and determination of the comprehensive value (step S13), if the comprehensive value of the thrust swaying impact sound is greater than the comprehensive value of the gear swaying impact sound, it is considered that the thrust swaying impact sound is dominant among the abnormal noises generated in the vehicle being measured (step S15), and the sound source inference processing ends.

[0045] As explained above, according to this embodiment, the source of the abnormal noise is inferred from the peak value in the sound data of the abnormal noise generated by the vehicle and the timing of the torque reversal of the drive motor. Therefore, it is possible to analyze abnormal noises originating from electric vehicles, which are relatively quiet due to low ambient noise, with high precision, and to take appropriate countermeasures against the occurrence and recurrence of the abnormal noise.

[0046] (Symbol Explanation)

[0047] P1, P2: Peak values; T: Reverse timing.

Claims

1. A sound source estimation method of a vehicle equipped with a drive motor, wherein sound data of a noise generated from the vehicle is acquired, in a case where a peak in the sound data exists after a reversal timing of a torque of the drive motor, it is determined that the noise is a noise due to a thrust shock, in a case where a peak in the sound data does not exist after the reversal timing of the torque of the drive motor, it is determined that the noise is a noise due to a gear rattle. ​

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