Sound source estimation method

Abstract

To provide a sound source estimation method that can accurately analyze abnormal noises generated from a vehicle and take measures to prevent the occurrence or recurrence of the abnormal noises. [Solution] A sound source estimation method for a vehicle equipped with a drive motor, in which sound data of abnormal noises generated by the vehicle is acquired, and if a peak P2 in the sound data exists after the timing T of torque reversal of the drive motor, it is determined that the abnormal noise is caused by thrust rattle, and if a peak P2 in the sound data does not exist after the timing T of torque reversal of the drive motor, it is determined that the abnormal noise is caused by gear rattle.

Description

[Technical Field]

[0001] The present invention relates to a sound source estimation method. [Background technology]

[0002] Patent Document 1 discloses that sound source candidates are extracted from vehicle travel information when an abnormal noise occurs, and the measurement position corresponding to the sound source candidate is notified based on the relationship between the sound source candidate and the measurement position of a sound source tracking device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-96554 Summary of the Invention [Problem to be solved by the invention]

[0004] Electric vehicles, which run on the driving force of a drive motor, have low background noise, so the rattle noise from the drive unit that occurs when the drive motor's rotation reverses (tip-in driving, tip-out driving) is easily noticeable.Furthermore, because their structure is relatively simple, it is easy to identify the source of the rattle noise.

[0005] However, there are two types of rattle noise: gear rattle noise that occurs between gears inside the drive unit, and thrust rattle noise that occurs when the bearings of the gears that move axially come into contact with the drive unit case. These types of rattle noises can occur singly or continuously within a short period of time, making it difficult to determine which type of rattle noise is dominant and take measures to prevent it from recurring.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a sound source estimation method that can accurately analyze abnormal noises generated by a vehicle and take measures to prevent the occurrence or recurrence of abnormal noises. [Means for solving the problem]

[0007] In order to achieve the above object, the sound source estimation method of the present invention includes: A sound source estimation method for a vehicle equipped with a drive motor, comprising: Acquire sound data of abnormal noises generated by the vehicle; If a peak exists in the sound data after a timing of reversal of the torque of the drive motor, it is determined that the abnormal noise is caused by thrust rattle. If there is no peak in the sound data after the timing of the torque reversal of the drive motor, it is determined that the abnormal noise is caused by gear rattle.

[0008] According to this sound source estimation method, the source of an abnormal noise is estimated based on the peak in the sound data of the abnormal noise and the timing of the torque reversal of the drive motor. This makes it possible to accurately analyze abnormal noises generated by electric vehicles with quiet background noise, and to take appropriate measures to prevent the occurrence or recurrence of abnormal noise. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a sound source estimation method that can accurately analyze abnormal noises generated from a vehicle and take measures to prevent the occurrence or recurrence of abnormal noises. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of meshing gears that explains the mechanism by which gear rattle noise occurs. [Figure 2] FIG. 2 is a schematic diagram of meshing gears to explain the principle behind the generation of thrust rattle noise. [Figure 3] FIG. 3 is a graph showing the relationship between the torque and thrust displacement of the drive motor and the sound pressure. [Figure 4] FIG. 4 is a flowchart of the sound source estimation process according to this embodiment. [Figure 5]FIG. 5 is a diagram illustrating unit information stored in the database. [Figure 6] FIG. 6 is a graph illustrating the overall process. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Fig. 1 is a schematic diagram of meshing gears to explain the principle of gear rattle generation, Fig. 2 is a schematic diagram of meshing gears to explain the principle of thrust rattle generation, and Fig. 3 is a graph showing the relationship between the torque and thrust displacement of the drive motor and sound pressure.

[0012] Electric vehicles run on the driving force of a drive motor (MG: Motor Generator) installed in a drive unit. Because electric vehicles have low background noise, rattles generated in the drive unit are easily noticeable. The rattles generated in the drive unit are mainly gear rattles and thrust rattles. Gear rattles and thrust rattles occur as abnormal noises, for example, when the drive motor reverses its rotation (tip-in running, tip-out running).

[0013] As shown in Fig. 1, gear rattle noise is generated when a tooth G1a of a gear G1 on the drive motor side comes into contact with a tooth G2a of a gear G2 on the wheel side. Also, as shown in Fig. 2, thrust rattle noise is generated when one of two meshing gears G3, G4 is displaced in the axial (thrust) direction (the direction of arrow D in Fig. 2) and a bearing B provided on the displaced gear G3 comes into contact with the case C of the drive unit.

[0014] Gear rattle noise occurs when the drive motor torque is reversed, while thrust rattle noise occurs after the drive motor torque is reversed. Therefore, as shown in Figure 3, when gear rattle noise and thrust rattle noise occur in a drive unit, a gear rattle noise peak P1 occurs simultaneously with or before the drive motor torque reversal timing T, and a thrust rattle noise peak P2 occurs after the drive motor torque reversal timing T.

[0015] Incidentally, it is difficult to estimate whether the dominant rattle noise generated by a vehicle is gear rattle noise or thrust rattle noise.

[0016] For this reason, in this embodiment, a sound source estimation process is performed to accurately analyze abnormal noises generated by the vehicle and estimate the sound source. The sound source estimation process will be described below with reference to the flowchart in FIG.

[0017] The sound data is obtained by measuring the sound generated by the vehicle during driving (step S01). This sound data includes the sound generated by the vehicle during tip-in driving with the accelerator on or tip-out driving with the accelerator off.

[0018] Vehicle type information of the vehicle to be measured is acquired (step S02). For example, a database stores vehicle type information of various vehicles, and vehicle type information corresponding to the vehicle to be measured is extracted from this database. This vehicle type information is, for example, information on an electric vehicle (BEV: Battery Electric Vehicle), an internal combustion engine vehicle (ICEV: Internal Combustion Engine Vehicle), a hybrid vehicle (HV: Hybrid Vehicle), etc.

[0019] Based on the vehicle type information of the vehicle under test, it is determined whether or not the vehicle under test is an electric vehicle (step S03).

[0020] Here, if the vehicle under test is a vehicle other than an electric vehicle, such as an engine vehicle or a hybrid vehicle, it is difficult to identify the location of the sound source because noise is louder in parts other than the drive unit equipped with the drive motor. Therefore, in determining whether the vehicle under test is an electric vehicle (step S03), if it is determined that the vehicle under test is not an electric vehicle (step S03: No), it is deemed difficult to estimate the sound source in the vehicle under test (step S04), and the sound source estimation process is terminated.

[0021] In determining whether the vehicle to be measured is an electric vehicle (step S03), if it is determined that the vehicle to be measured is an electric vehicle (step S03: Yes), the torque of the drive motor is read (step S05).

[0022] The sound data is applied to the torque of the drive motor, and the timing T at which the torque of the drive motor changes from positive to negative is compared with the sound peaks P1 and P2 (see FIG. 3). As a result, it is determined whether the sound peak P2 exists after the timing T at which the torque changes (step S06).

[0023] In determining whether or not a sound peak P2 exists after the reversal timing T (step S06), if it is determined that a sound peak P2 does not exist after the reversal timing T (step S06: No), it is determined that only gear rattle noise is occurring in the drive unit (step S07), and the sound source estimation process is terminated.

[0024] In determining whether or not a sound peak P2 exists after the reversal timing T (step S06), if it is determined that a sound peak P2 exists after the reversal timing T (step S06: Yes), it is estimated that this sound peak P2 is a thrust rattle noise (step S08).

[0025] Information about the drive unit is acquired (step S09). For example, a database stores information about the presence or absence of thrust rattle for each type of drive unit, and information about the drive unit installed in the vehicle to be measured is extracted from this database.

[0026] It is determined whether or not the drive unit mounted on the vehicle to be measured is a unit that has thrust play (step S10).

[0027] Here, FIG. 5 is a diagram for explaining information on the units stored in the database. As shown in Fig. 5, the database stores information on the presence or absence of thrust rattle in various units A, B, and C. In the example of Fig. 4, units A and B have no thrust rattle (see "x" in Fig. 5), and unit C has thrust rattle (see "o" in Fig. 5). If the drive unit installed on the vehicle to be measured is unit C, it is determined that there is thrust rattle.

[0028] In determining whether or not there is thrust rattle (step S10), if it is determined that there is no thrust rattle in the drive unit installed in the vehicle being measured (step S10: No), it is determined that the abnormal noise generated in the vehicle being measured does not include thrust rattle (step S11), and the sound source estimation process is terminated.

[0029] In determining whether or not there is thrust rattle (step S10), if it is determined that there is thrust rattle in the drive unit installed in the vehicle being measured (step S10: Yes), it is determined that the abnormal noise generated in the vehicle being measured includes thrust rattle noise (step S12).

[0030] Overall (OA) processing is performed on the gear rattle noise and thrust rattle noise in the sound data, and the sound levels of each sound are compared and analyzed using an overall value. In the overall processing, as shown in Figure 6, the overall (OA) value is calculated by summing up the sound pressure at all frequencies. Then, it is determined whether the overall value of the thrust rattle noise is greater than the overall value of the gear rattle noise (step S13).

[0031] In the comparison judgment of the overall values ​​(step S13), if the overall value of the gear rattle noise is equal to or greater than the overall value of the thrust rattle noise, it is determined that the gear rattle noise is the dominant abnormal noise occurring in the measured vehicle (step S14), and the sound source estimation process is terminated.

[0032] If the overall value of the thrust rattle noise is greater than the overall value of the gear rattle noise in the comparison of the overall values ​​(step S13), it is determined that the thrust rattle noise is the dominant abnormal noise occurring in the measured vehicle (step S15), and the sound source estimation process is terminated.

[0033] As described above, according to this embodiment, the source of an abnormal noise is estimated based on the peak in the sound data of the abnormal noise generated by the vehicle and the timing of the torque reversal of the drive motor. This makes it possible to accurately analyze abnormal noise generated by an electric vehicle with quiet background noise, and to take appropriate measures to prevent the occurrence or recurrence of the abnormal noise. [Explanation of symbols]

[0034] P1, P2 peaks T Reverse timing

Claims

[Claim 1] A sound source estimation method for a vehicle equipped with a drive motor, comprising: Acquire sound data of abnormal noises generated by the vehicle; If a peak exists in the sound data after a timing of reversal of the torque of the drive motor, it is determined that the abnormal noise is caused by thrust rattle. If there is no peak in the sound data after the timing of the torque reversal of the drive motor, it is determined that the abnormal noise is caused by gear rattle. Sound source estimation method.

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