JP2006306278A - Estimation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and accurately estimate the noise of a gear device where real condition of the noise can hardly be grasped by focusing attention on the under floor noise as a traveling noise of a railway rolling stock. <P>SOLUTION: An actual measurement value α of the noise in the vicinity of under floor of a truck of M vehicle, and the actual measurement value β of the noise in the vicinity of under floor of the truck of T vehicle are obtained from the travel test of the M vehicle and T vehicle, and the noise δ of the drive system is obtained based on the actual measurement value α and β. In a high speed area where aerodynamic sound is dominant as the noise of a main motor 1, the actual measurement value γ of the main motor noise obtained from a stationary test of the main motor 1 is corrected based on the difference between the measurement condition of the travel test and the measurement condition of the stationary test. The estimation value ε of the gear device body is obtained from the difference between the correction value of the actual measurement value γ and the noise δ of the stationary test. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an estimation method for estimating noise of a gear device of an electric vehicle.

  The noise caused by the running of railway vehicles has a great influence on the railway and passengers. For this reason, the noise level is one of the important design conditions of railway vehicles, and the section where the driving speed is regulated so that the noise level is below a certain value on the route passing through densely populated houses. There is also.

  In addition, before actual driving, the noise of the entire railway vehicle is measured in a running test, and a stationary test is performed to measure the noise of the main motor as defined by JIS (Japanese Industrial Standards). Yes.

A technique is known in which the sound of a differential gear of a vehicle is determined by detecting the magnitude of vibration based on the fact that the magnitude of vibration has a certain relationship with the magnitude of noise (Patent Document 1). Is a technology that focuses on the differential gear of the vehicle.
JP-A-8-136407

  However, the noise of the entire railway vehicle is caused by a plurality of factors. For this reason, a method is desired in which each sound source that is an individual factor is investigated and distinguished, and measures are preferentially taken from the largest, or measures are taken according to the contribution ratio of the sound source to noise. Therefore, first of all, it is desirable to clarify the actual condition of each sound source that causes noise.

  However, even if attention is paid to the under-floor noise of the railway vehicle, there are a plurality of sound sources such as rolling noise (noise generated when the wheel travels on the rail) and gear device noise in addition to the noise of the main motor. Therefore, the contribution rate of other sound sources cannot be accurately grasped only by obtaining the noise of the main motor alone.

  Further, the stationary test of the main motor measures noise in a no-load state, and does not measure noise of the main motor in a state where a load is applied during traveling. That is, the stationary test is performed in a situation different from the actual operating environment of the main motor, and the measurement result in the no-load state is not very useful for knowing the noise of the motor during actual running.

  As described above, it is difficult to clarify the actual condition of each sound source that is a cause of noise during running of a railway vehicle. However, it is effective to not clarify the actual condition of each sound source one by one. Measures for noise reduction cannot be taken.

  Accordingly, the present invention has been made with the object of easily and accurately estimating the noise of the gear unit, which is difficult to grasp the actual state of the noise, focusing on the under-floor noise as the noise during running of the railway vehicle.

In order to solve the above problem, the first invention is:
Based on the measured value α of the noise near the undercarriage of the electric vehicle, the measured value β of the noise near the undercarriage of the accompanying vehicle, and the measured value γ of the stationary test of the main motor of the electric vehicle, the gear device of the electric vehicle An estimation method for estimating noise,
In a high speed range where aerodynamic noise is dominant as the noise of the main motor, the drive system noise of the electric vehicle is obtained from the difference between the measured values α and β, and the difference between the obtained drive system noise and the measured value γ This is an estimation method for estimating the noise of the gear device in a high speed range.

  The high speed range where the aerodynamic noise is dominant here means that the aerodynamic noise included in the noise of the main motor occupies a certain ratio or more with respect to the electromagnetic noise caused by the main motor itself. An area or a speed area of an electric vehicle driven by the main motor.

Further, the concept of obtaining the driving system noise of the M car from the difference between the mounted values α and β and estimating the noise of the gear device in the high speed range from the difference between the obtained driving system noise and the actual measurement value γ is as a concept. It can be simply shown as the following equation (1).
Estimated noise value of gear unit = (α−β) −γ (1)
On the other hand, the arithmetic expression (1) is substantially equivalent to the following arithmetic expressions (2) and (3).
α- (β + γ) (2)
(Α-γ) -β (3)
Therefore, a method for estimating the noise of the gear device by replacing the estimation method of the first invention described above with an equivalent method such as the arithmetic expressions (2) and (3) is based on the concept and idea of the first invention. It is included and at least equivalent.

  According to the first invention, in the high speed range where aerodynamic noise is dominant as the noise of the main motor, the drive system noise of the electric vehicle is obtained from the difference between the measured values α and β, and the obtained drive system noise and the measured The noise of the gear device in the high speed range can be estimated from the difference from the value γ. Therefore, it is possible to easily estimate the noise of the gear unit that is difficult to measure by actual measurement. In addition, it is possible to obtain a highly accurate estimated value by estimating the noise of the gear device based on the actual measurement value γ of the stationary test of the main motor in a high speed range where aerodynamic noise is dominant.

The second invention is the estimation method of the first invention,
After correcting the actual measurement value γ based on the difference between the measurement condition of the actual measurement value α and the measurement condition of the actual measurement value γ, the difference between the obtained drive system noise and the corrected actual measurement value γ is calculated in the high speed range. This is an estimation method for estimating the noise of a gear device.

  According to the second invention, even when the measurement value α and the measurement value γ are different, the noise of the gear device is estimated after correcting the measurement value γ based on the difference in the measurement condition. Therefore, an accurate estimated value can be obtained. Moreover, since it is not restrained by one measurement condition, the running test of an electric vehicle and an accompanying vehicle and the stationary test of a main motor can be performed easily.

  According to the present invention, the noise of the gear device can be calculated easily and accurately. Thereby, the actual state of the sound source with respect to the noise of the railway vehicle can be clarified, and it can be the beginning of taking effective noise countermeasures according to each sound source.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to FIGS. However, the scope of the invention is not limited to the illustrated examples.

1. Speed multiplication law of gear device Generally, sound has speed dependency. In other words, if it is a noise of a railway vehicle, it is assumed that it follows the power of the speed of the railway vehicle, and it is known that the power exponent depends on the nature of the sound source. Then, it tried to obtain | require the speed law of a gear apparatus as a noise characteristic from the measured value of a running test.

  First, in a running test, noise is measured by providing a measurement point at a position near the upper part of the gear unit under the vehicle floor, thereby obtaining noise near the gear unit as an actual measurement value. However, the gear device is a device mounted in the vicinity of the main motor, and it is not clear whether the actual measurement value with the measurement point near the upper portion of the gear device accurately indicates the noise of the gear device alone. Therefore, focusing on the peak corresponding to the meshing frequency of the gear of the gear device, spectrum analysis of the obtained actual measurement value was performed.

  FIG. 1A is a graph showing the analysis result of the 1/3 octave band of the noise near the top of the gear device during traveling at constant speed. In FIG. 1A, a peak in the frequency band of 800 Hz can be confirmed in the spectrum of the frequency during running at constant speed of 90 km / h (the spectrum indicated by ◯ in the figure). This peak corresponds to the gear meshing frequency (907 Hz) obtained from the calculated value, and is considered to be direct noise from the gear. In addition, a peak in the frequency band of 1.25 kHz can be confirmed in the spectrum of the frequency during traveling at a constant speed of 130 km / h (the spectrum indicated by Δ in the figure). This peak corresponds to the gear meshing frequency (1.3 kHz) obtained from the calculated value, and is considered to be direct noise from the gear.

Therefore, the speed multiplication law of the gear unit alone was calculated from the noise level indicating the direct noise from the gears during constant speed power running at 90 km / h and 130 km / h. The result is shown in FIG. As shown in FIG. 1B, the difference between the peak noise level in the 800 Hz frequency band and the peak noise level in the 1.25 kHz frequency band is 8.15 dB. By substituting these into the following equation (4), an n-th power law is obtained.
8.15 = n × log (130/90) (4)

  From the above equation (4), the noise characteristic of the gear unit based on the actually measured value was obtained as the fifth power law. FIG. 1B shows the theoretical value “7.98” of the noise level in the fifth power rule, which is substantially coincident with the actually measured value “8.15”. From the above, it was found that the noise of the gear unit alone follows the fifth power law of the railway vehicle.

2. Measurement of noise during a running test Next, an electric vehicle (a rail vehicle equipped with a driving device; hereinafter referred to as “M vehicle”) and an accompanying vehicle (a rail vehicle not equipped with a driving device; hereinafter referred to as “T vehicle”). A driving test was conducted to determine drive system noise (noise generated from driving devices such as the main motor and gear device) and rolling noise (noise generated when the wheel traveled on the rail).

  Here, there are rolling noise and driving system noise as the main under-floor noise when the railway vehicle is running. The rolling noise is obtained by actually measuring the noise near the undercarriage of the T car, and the drive system noise is the measured value of the noise near the undercarriage of the M car and the rolling noise (that is, the noise near the undercarriage of the T car). It is obtained as a difference from the actual measurement value). Therefore, a running test was performed for M and T cars, and the noise near the under-floor carriage of each vehicle was measured.

  With reference to FIG. 2, the measurement conditions of the running test will be described. 2A is a top view of the main motor 1 mounted on the M car, FIG. 2B is a side view of the main motor 1 as viewed from the front, and X in the figure is an underfloor carriage It shows the approximate installation position of the microphone for measuring the nearby noise. In addition, the floor position of M car is shown in the figure (b), and it abbreviate | omits about each other part. As shown in FIG. 2, the position X is generally installed at a position about 0.5 m above the main motor 1 and is fixed under the floor of the M car. In addition, as a measurement condition for the T car, a microphone was installed at a position below the floor of the T car corresponding to the microphone installation position X of the M car. Further, the main motor used in this measurement has exhaust ports 1a opened on the left and right sides on the output shaft side of the side surface, and an intake duct 1b on the upper side of the main motor opposite to the exhaust port 1a. Yes.

  Next, a method for obtaining drive system noise based on the measured value of the noise near the undercarriage truck will be described. FIG. 3A is a diagram for explaining data of M cars and T cars obtained by a running test. As shown in FIG. 3 (a), the measured value of the noise near the undercarriage of the M car is the total underfloor noise, that is, the sum of the power of the drive system noise and the rolling noise, and the actual noise of the noise near the undercarriage of the T car. The value is rolling noise. Therefore, as shown in FIG. 3B, the drive system noise is obtained as a calculated value from the difference between the entire underfloor noise (actual value of the M vehicle running test) and rolling noise (actual value of the T vehicle running test). .

4). Principle of noise measurement of the main motor 1 The drive system noise obtained is a noise mainly including the noise of the main motor 1 and the noise of the gear unit. Therefore, it is necessary to further separate the obtained drive system noise into the noise of the main motor 1 and the noise of the gear unit. Then, it tried to obtain | require the noise of the main motor 1 as a measured value by measuring the noise of the main motor 1 by a stationary test.

  By the way, as described above, the stationary test of the main motor 1 measures noise in a situation different from the actual operating environment of the motor, so it is considered that it is not very useful for knowing the noise situation during traveling. It was. That is, in the main motor 1 that is actually mounted on a railway vehicle, a joint or an axle is connected to the output shaft, and a mechanical load is applied to the main motor 1, so that an electromagnetic excitation force is generated. However, since the stationary test is a measurement in a no-load state in which these loads are not applied, the measured noise does not include electromagnetic noise due to a mechanical load, and the accuracy is inferior. However, by measuring the noise of the main motor 1 in a driving state in which different voltages are applied as terminal voltages while maintaining a constant rotational speed, the noise of the main motor 1 measured in the stationary test is constant at a high speed. In the region, it was found that it can be regarded as noise of the main motor 1 alone during traveling.

4-1. Measurement conditions First, the measurement conditions in the stationary test will be described. FIG. 4 is a diagram for explaining the noise measurement position in the noise measurement of the main motor 1. FIG. 4A is a plan view of the main motor 1, and FIG. 4B is a side view of the main motor 1 as viewed from the front. The positions A, B, C, D, and E in the figure indicate the positions of microphones that are installed to measure the noise of the main motor 1. Further, as shown in FIG. 4A, the left side of the page is the front side of the main motor 1, the right side is the rear side of the main motor 1, the upper side is the right side of the main motor 1, and the lower side is the left side of the main motor 1. explain. Further, as shown in FIG. 1B, the following description will be made with the left side of the drawing as the right side of the main motor 1, the upper side as the upper side of the main motor 1, and the right side as the left side of the main motor 1. Note that a position X in the figure indicates a microphone installation position in the running test shown in FIG. 2 for comparison.

  Positions A, B, C, and D are on a horizontal plane that includes the axial center line of the main motor 1, the position A is a position that is 1 m away from the front end (not including the shaft) of the main body of the main motor 1, and the position B is It is a position 1 m away from the right side end of the main body of the main motor 1. Position C is a position 1 m away from the rear end of the main body of the main motor 1, and position D is a position 1 m away from the left end of the main body of the main motor 1. Position E is a position 1 m away from the upper end of the main body of the main motor 1 in the vertical direction. Thus, noise measurement was performed at a total of five positions.

4-2. Measurement Principle Next, the main motor noise measurement method will be described. As the main motor 1, an induction motor was used. The rated rotation speed of the main motor 1 is 2555 times per minute, and noise measurement was performed for 1800 times per minute and 2940 times per minute, which are the rotation speeds before and after that. In addition, the power source of the main motor 1 is an inverter power source. When the main motor 1 is rotated 1800 times per minute, the pulse output pattern of the inverter power source is set to the multi-pulse mode, and when the main motor 1 is rotated 2940 times per minute, the single pulse mode is set. Voltage supply was performed. Further, the duty ratio of PWM control used for the inverter power source is constant, and only the voltage applied to the main motor 1 is changed.

  FIG. 5A is a graph showing the relationship between the terminal voltage and the terminal current when the rotation speed of the main motor 1 is 1800 times per minute and 2940 times per minute. Here, the terminal current is a stator current. FIG. 5A shows that the terminal current increases as the terminal voltage increases at any rotational speed. A large terminal current indicates that the magnitude of the magnetic flux that excites the casing is large. The degree of increase of the terminal current with respect to the increase of the terminal voltage is larger at 1800 times per minute, which is a low rotation speed. That is, it can be said that the increase in the electromagnetic excitation force with respect to the increase in the terminal voltage is larger at the low rotation speed.

  In addition, each driving state in which a different voltage is applied as the terminal voltage while maintaining a constant rotational speed changes the magnitude of the magnetic flux that excites the casing, so that the motor is in a different load motion. It can be said that the generated electromagnetic excitation force can be created. That is, it is possible to simulate the electromagnetic excitation force with the load machine connected. According to the principle of the noise measurement method described above, noise was measured by changing the measurement terminal voltage, but the change in the measurement terminal voltage is equivalent to changing the magnitude of the magnetic flux due to the load. Therefore, the noise measuring method of the present embodiment can apply the electromagnetic excitation force to the main motor 1 without connecting the load machine and measure the noise of the main motor 1 in a situation close to the actual operating environment. This is not necessary and is effective as a method for measuring the noise of the main motor 1 alone.

4-3. Measurement Result Next, the measurement result will be described. FIG. 5B is a graph showing the relationship between the terminal voltage of the main motor 1 and the sound pressure level of noise generated from the main motor 1. The sound pressure levels at position A and position B when the main motor 1 is driven at a rotational speed of 1800 times per minute and 2940 times per minute are graphed. The position A is a measurement position (hereinafter referred to as “load side”) on the output shaft side of the motor, that is, the side to which the load machine is connected. The sound pressure level at position B is shown as a representative of the measurement positions (hereinafter simply referred to as “side surfaces”) on the left and right side, rear and upper sides of the electric motor.

As shown in FIG. 5B, the sound pressure level increased with increasing terminal voltage at a rotational speed of 1800 times per minute. Further, as the terminal voltage increased, the sound pressure level tended to increase at the side position B on the stator side rather than at the position A on the load side. At position B, as the terminal voltage is increased, the stator coil is vibrated and the sound generated by electromagnetic vibration from the surface of the cylindrical casing is radiated, so that the noise is large. At position A, the casing on the output shaft side is It is considered that no significant noise is generated even if the terminal voltage is increased because the vibration is hardly applied.
Further, since 1800 times per minute corresponds to a low speed range of the railway vehicle, it coincides with a tendency that noise when the speed of the railway vehicle is low temporarily increases.

  Further, when driving at a low rotational speed of 1800 times per minute, the rotational speed of the rotor is also low, so that the amount of aerodynamic sound generated around the rotor is output from the exhaust port 1a is small. Therefore, it can be said that the noise generated when the electric motor is driven 1800 times per minute accounts for a large proportion due to electromagnetic noise.

  On the other hand, as shown in FIG. 5A, even when the same terminal voltage is applied, the terminal current is 2940 times per minute smaller than 1800 times per minute. That is, as the voltage increases, the electromagnetic excitation force increases, but the rate is smaller than 1900 times per minute.

  Further, at the high speed rotation of 2940 times per minute, the rotational speed of the rotor is increased, and more wind noise is generated around the rotor, so that a large aerodynamic sound is generated from the main motor 1. Both positions A and B are strongly influenced by aerodynamic sound from the exhaust port 1a. And since this wind noise etc. are output from the exhaust port 1a, the load side (position A) becomes larger than the side surface side (position B). As a result, even if the voltage is increased to increase the electromagnetic excitation force, the sound emission from the cylindrical casing surface is smaller than the aerodynamic sound and is masked and does not appear as a change. In addition, although the aerodynamic sound is loud at both positions A and B, the position A closer to the exhaust port 1a shows a slightly higher noise level.

  From the above, in a constant high speed range (for example, 2940 times or more per minute), the noise generated from the main motor 1 has a large proportion of noise due to aerodynamic sound, and the noise due to electromagnetic sound can be almost ignored. That is, if the electromagnetic noise generated by the main motor 1 itself is negligible, it is considered that the electromagnetic noise generated by the mechanical load is small enough to be ignored. Therefore, in the high speed range, the actual measured value of the main motor noise in the stationary test can be regarded as the noise of the main motor 1 during actual traveling.

  Although the description has been made so that the high speed range is determined from the rotation speed of the main motor 1, the rotation speed of the main motor 1 is considered to be equivalent to the speed of the railway vehicle, and therefore, the high speed range may be determined from the traveling speed.

5. Principle of Calculation of Gear Device Noise Estimated Value A method of calculating the gear device noise estimated value based on the drive system noise obtained above and the noise of the main motor 1 will be described. As shown in FIG. 6A, the drive system noise is noise mainly including noise of the main motor 1 and noise of the gear device. Therefore, the noise of the gear unit alone can be estimated from the difference between the drive train noise obtained in 3 and the noise of the main motor 1 obtained in 4 above.

  Here, the measurement conditions for the noise near the undercarriage of the M car and T car, which are operators of the drive system noise, and the measurement conditions for the main motor noise are different measurement conditions. Therefore, it is necessary to correct the actual noise measurement value of the main motor 1 obtained from the stationary test based on the difference in measurement conditions.

  That is, as shown in FIG. 4, the distance between the installation position of the main motor 1 and the microphone is twice as long in the running test position X as compared with the stationary test position E. Therefore, in order to correct this double distance difference, “3 dB” is added to the actual noise measurement value of the main motor 1. In the running test, since the microphone is installed under the floor of the carriage, it is affected by the reflected sound from the floor surface. Therefore, in order to correct the influence of the reflected sound from the floor surface, “3 dB” is added to the noise actual measurement value of the main motor 1. That is, the error due to the difference in measurement conditions is corrected by adding a correction value of 6 dB in total to the noise actual measurement value of the main motor 1. Then, as shown in FIG. 6 (b), the estimated value of the noise of the gear unit alone can be calculated based on the corrected noise actual measurement value of the main motor 1.

  FIG. 7 (a) shows the whole floor noise (actual value α), rolling noise (actual value β), drive system noise (calculated value δ), main motor (corrected γ), gear device (estimated value ε) as sound sources. ) And the speed of the railway vehicle. That is, it shows the speed dependence of noise as seen by sound source.

  Further, when the speed power law was calculated based on the estimated value ε of the obtained gear device, the speed power law was obtained as the fifth power law as shown in FIG. In other words, in the above 1, the speed multiplication law obtained from the actual measurement value of the gear unit alone is in agreement, and it can be said that the estimated noise value ε of the gear unit is a reliable value.

  In FIG. 7 (a), the value of the noise level at a traveling speed of 80 km / h or higher of the railway vehicle is shown. This is because the speed higher than the speed is the above-mentioned high speed range (for example, the electromagnetic of the main motor 1). This is because it can be considered as a speed range where sound can be ignored.

6). Processing Flow Next, a processing flow of the gear device noise estimation method will be described. FIG. 8 is a flowchart for explaining the flow of the noise estimation processing of the gear device. First, in FIG. 8, the noise near the undercarriage of the M car, that is, the actual measurement value α obtained by the running test of the M car is acquired (step S2). Next, the noise near the undercarriage of the T car, that is, the actual measurement value β obtained by the running test of the T car is acquired (step S4).

  Subsequently, an actual measurement value γ obtained by a stationary test of the main motor 1 is acquired (step S6). Then, the obtained actual measurement value γ is corrected based on the difference between the measurement condition of the running test and the measurement condition of the stationary test (step S8). Specifically, the measurement condition for the running test is a distance 0.5 m away from the main motor 1 as a measurement position, and a floor is provided on the top of the main motor 1. On the other hand, the measurement condition of the stationary test is that a distance 1 m away from the main motor is a measurement position, and nothing is provided on the upper portion of the main motor 1. Therefore, “+3 dB” as a correction for the ratio of the separation distance, and “+3 dB” as a correction for the amplification by the reflected sound from the floor surface provided on the upper portion of the main motor 1 are added to the actual measurement value γ to obtain a corrected γ And

  Next, the drive system noise δ is calculated from the difference between the actually measured values α and β of the running test (step S10). Then, an estimated value ε of the gear unit noise is calculated from the difference between the drive system noise δ and the corrected γ (step S12).

7). As described above, the measured value α of the noise near the undercarriage of the M car and the measured value β of the noise near the undercarriage of the T car are obtained from the running test of the M car and the T car. Drive system noise δ is obtained based on β. Further, in the high speed range where aerodynamic noise is dominant as the noise of the main motor 1, the measured value γ of the main motor noise obtained from the stationary test of the main motor 1 is the difference between the measurement condition of the running test and the measurement condition of the stationary test. Correct based on the difference. And the estimated value (epsilon) of a gear apparatus single-piece | unit can be calculated | required from the difference of the correction value of measured value (gamma), and drive system noise (delta).

  Thereby, it is possible to easily estimate the noise of the gear unit alone, which is difficult to measure by actual measurement, from the calculation based on the actual measurement values obtained from the running test of the M and T cars and the stationary test of the main motor 1. In addition, in the high-speed range, the noise measurement value of the main motor in the stationary test is regarded as the noise status of the motor during actual running, and the noise of the gear unit alone is estimated. Can be calculated.

  Furthermore, since the noise actual measurement value γ of the main motor 1 is corrected based on the difference between the measurement conditions of the running test and the stationary test, the noise of the main motor 1 alone can be accurately obtained even when the measurement conditions are different. it can. Thereby, the estimated value of the gear unit alone can be obtained with high accuracy, and the contribution ratio of each sound source to the drive system noise can be obtained accurately. Moreover, since it is not restrained by one measurement condition, a running test and a stationary test can be performed as usual.

  From the above, it is possible to clarify the actual state of the sound source with respect to the noise of the railway vehicle, and to start effective noise countermeasures according to each sound source.

8). The embodiment to which the present invention is applied has been described above, but the present invention is not limited only to the above-described embodiment, and various modifications can be made without departing from the gist of the present invention. Of course.

  For example, in the present embodiment, the case where an induction motor is used as the motor has been described, but it is needless to say that the present invention may be applied to a synchronous motor or a DC motor.

  Moreover, although the case where the measured value γ of the main motor is corrected based on the difference between the measurement conditions of the running test and the stationary test has been described, the drive system noise δ or the noise near the undercarriage of the M car and the under floor of the T car The near-bogie noise β may be corrected.

The figure explaining the method of calculating | requiring the speed law of the gear apparatus noise from the gear apparatus vicinity noise. The figure which shows an example of the measurement conditions of the main motor in the running test of a rail vehicle. The figure explaining the noise obtained from the measured value of the running test of a railway vehicle. The figure which shows an example of the measurement conditions of the main motor in a stationary test. (A) a graph showing the relationship between the terminal voltage and the terminal current when the rotation speed of the main motor is constant, (b) the relationship between the terminal voltage of the main motor and the sound pressure level of the noise generated from the main motor at that time FIG. The figure explaining the noise obtained from the stationary test of the main motor. (A) The figure which shows the speed dependence of the noise seen for every sound source, (b) The figure which shows the speed riding side for every sound source. It is a flowchart which shows the flow of the noise estimation process of a gear apparatus.

Explanation of symbols

1 Main motor A, B, C, D, E, X Noise measurement position

Claims (2)

Based on the measured value α of the noise near the undercarriage of the electric vehicle, the measured value β of the noise near the undercarriage of the accompanying vehicle, and the measured value γ of the stationary test of the main motor of the electric vehicle, the gear device of the electric vehicle An estimation method for estimating noise,
In a high speed range where aerodynamic noise is dominant as the noise of the main motor, the drive system noise of the electric vehicle is obtained from the difference between the measured values α and β, and the difference between the obtained drive system noise and the measured value γ An estimation method for estimating noise of a gear device in a high speed range.   After correcting the actual measurement value γ based on the difference between the measurement position condition of the actual measurement value α and the measurement position condition of the actual measurement value γ, the difference between the obtained drive system noise and the corrected actual measurement value γ The estimation method of Claim 1 which estimates the noise of the gear apparatus in the said high-speed area from.

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