JP2023161245A - Method and device for determining higher-order gear noise - Google Patents

Abstract

To accurately extract higher-order noise that may occur a plurality of times and also change in order, and determine or evaluate the same.SOLUTION: A device for determining noise generated by gears includes a sound collector 9 that collects the noise, a tracking processing unit 15 that tracks the collected noise and outputs a map with parameters of rotation number, frequency, and sound pressure, a pickup unit 16 that defines a higher-order noise range in a predetermined range in a rotation number and frequency in the map, an extraction unit 17 that finds cumulative values of sound pressure on a plurality of order components in the higher order noise range that has high sound pressure and extracts a plurality of order components in the order of increasing cumulative values, and a determining unit 18 that determines whether the sound pressure in each of the plurality of order components extracted exceeds a predetermined determination standard value.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for determining the noise of gears caused by tooth meshing as the gear rotates, and a device for the determination.

Gears generate noise due to teeth meshing with each other and noise due to rotation, and the frequency of the noise changes depending on the rotation speed. Tracking analysis is known as a method of analyzing such noise, and one example thereof is described in Patent Document 1.

The device described in Patent Document 1 is a device for determining gear noise, which performs order tracking analysis corresponding to the number of teeth of the target gear, and calculates an evaluation index based on the sound pressure obtained as a result. seek. On the other hand, a sound pressure level that an observer perceives as abnormal is determined in advance as a threshold for determination, and the threshold is compared with an evaluation index. The evaluation index is a value obtained by averaging the sound pressure within a predetermined frequency range, or a weighted average of the averaged value and the averaged value similarly obtained for overtones.

Therefore, according to the device described in Patent Document 1, a value based on the observer's sensibilities is adopted as a threshold value, so vibrations that reflect ease of sensing, discomfort, etc., are not simply caused by high sound pressure. Noise evaluation can be performed. Furthermore, since the above-mentioned average value is compared with the threshold value instead of simply using the peak value, the influence of disturbance can be reduced and the determination accuracy can be maintained.

JP2019-109211A

The analysis method adopted by the device described in Patent Document 1 is an order tracking analysis, which, as also described in Patent Document 1, intentionally changes the rotation speed and This is a method that follows the speed and extracts and analyzes only the corresponding order components. Therefore, it is possible to determine the magnitude of the sound pressure for preselected and set order components, but it is not possible to determine the noise of orders that have not been set, and the order changes like high order noise. In this case, analysis and judgment (or evaluation) cannot be performed.

This invention was made with a focus on the above-mentioned technical problem, and it is possible to accurately extract high-order noise that occurs in multiple numbers and whose order changes, and to perform judgment or evaluation thereof. It is an object of the present invention to provide a high-order gear noise determination method and determination device.

In order to achieve the above object, the present invention provides a high-order gear noise determination method for determining noise generated when gears mesh with each other and rotate. A map is created using the rotation speed, frequency, and sound pressure as parameters by tracking the noise, a high-order noise range of a predetermined rotation speed and frequency is defined in the map, and a high-order noise range of the high-order noise range is defined in advance. In this process, the cumulative value of the sound pressure is determined for the noise of multiple order components with high sound pressure, and the multiple order components are extracted in descending order of the cumulative value. The present invention is characterized in that it is determined whether the sound pressure exceeds a predetermined determination reference value.

The present invention also provides a high-order gear noise determination device that determines noise generated when gears mesh with each other and rotate, comprising: a sound collector that collects noise generated from the gears; and a sound collector that collects the noise generated from the gears; a tracking processing unit that performs tracking processing and outputs a map with rotation speed, frequency, and sound pressure as parameters; a pickup unit that defines a high-order noise range of a predetermined rotation speed and frequency in the map; an extraction unit that calculates the cumulative value of sound pressure for noise of multiple order components with high sound pressure within the order noise range and extracts the multiple order components in descending order of the cumulative value; and a determination unit that determines whether the sound pressure in each of the order components exceeds a predetermined determination reference value.

According to the present invention, even high-order gear noise that occurs multiple times and whose order changes can be detected and determined without fail. Further, since the cumulative value is used as described above, it is possible to avoid or suppress the introduction of noise that suddenly occurs as background noise or environmental noise, and to perform accurate determination.

FIG. 2 is a schematic diagram showing a differential gear in a transaxle as an example of a gear. FIG. 2 is a block diagram showing the functional configuration of a determination device. It is a three-dimensional map of rotation speed, frequency, and sound pressure, where (A) shows the map obtained by NV measurement processing, and (B) shows a map of the high-order noise range cut out from the map in a predetermined range. . FIG. 3 is a diagram schematically showing a graph in which sound pressure is accumulated for each order component. FIG. 7 is a waveform diagram showing the results of tracking analysis for order components with large cumulative values together with determination reference values. 2 is a flowchart for explaining an example of control for determination performed in the embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the drawings. Note that the embodiment described below is only an example of implementing the present invention, and is not intended to limit the present invention.

An example of a gear that generates noise that is subject to determination in this invention is schematically shown in FIG. 1. The gear shown here is differential gear 1 that constitutes a transaxle in a hybrid vehicle, and The configuration is similar to a differential gear in a general vehicle: a pair of side gears 2 arranged oppositely on the same axis, a pinion gear 4 meshing with these side gears and rotatably held in a differential case 3, It consists of a ring gear 5 attached to a differential case 3. Left and right drive shafts (not shown) are connected to each side gear 2 . A drive gear 7 that transmits output torque of a hybrid drive device 6 is meshed with the ring gear 5 . The hybrid drive device 6 constitutes a driving force source together with an engine 8 such as a conventionally known two-motor type drive device.

The differential gear 1 is assembled together with the hybrid drive device 6 as part of a transaxle, and subjected to noise inspection on the line. Noise inspection is performed by rotating the differential gear 1, collecting the noise generated at that time using a sound collector 9 such as a microphone, and performing tracking analysis using the determination device 10. A sensor 11 is provided to detect the rotational speed of the differential gear 1 necessary for tracking analysis, and its detection signal is input to the determination device 10.

The determination device 10 is mainly composed of a computer, and receives data inputted from the sound collector 9 (noise signal), data inputted by an operation unit 12 such as a keyboard, data stored in advance, etc. It is configured to use the computer to perform calculations based on a predetermined program. Further, the determination device 10 can be connected to a monitor 13 and a printer 14 as output devices, and is configured to output the status and results of the tracking process.

In an embodiment of the present invention, collected noise is tracked to create a map based on rotational speed, frequency, and sound pressure, a high-order noise range is defined from the map, and noise is determined using the high-order noise range. conduct. In other words, some of the noise that is collected is beyond the audible range, and some noise that is within the audible range does not pose a particular problem due to background noise, environmental noise, etc. In order to make a determination, a range of noise to be determined is specified. In other words, the high-order noise range is cut out from the map. Then, the cumulative value of the sound pressure is determined for the order components of the noise with high sound pressure within the high-order noise range. The order components are extracted in descending order of cumulative value, and it is determined whether the maximum sound pressure of the extracted order components exceeds the determination reference value.

Specifically, the determination device 10 has a function of determining (or evaluating) high-order gear noise generated in the above-mentioned differential gear 1, which is the object of inspection or determination, among the noises captured by the sound collector 9. have. The functional configuration for this determination is shown in a block diagram in FIG.

The signals (data) input from the sound collector 9 and sensor 11 are converted into digital signals, and processed to be measured as vibration noise (NV measurement processing), and the obtained data is converted into sound pressure for each rotation speed and frequency. Perform tracking processing to map as . A tracking processing section 15 that performs this processing is provided, and the tracking processing section 15 performs tracking processing that involves conventional general FFT (fast Fourier transform) for analyzing vibrations and noise of rotating members. It may be configured.

The map obtained by tracking processing is a map with rotation speed, frequency, and sound pressure as parameters.If each parameter is expressed as a coordinate axis, it becomes a three-dimensional map, and on the other hand, sound pressure can be expressed with colors and shading. It becomes a two-dimensional map (color three-dimensional map). A three-dimensional map is schematically shown in FIG. 3(A), and each of the lines in FIG. 3(A) that slope upward to the right so that the frequency increases as the rotation speed increases, It represents the order. Therefore, (A) in FIG. 3 shows the sound pressure of noise generated as the differential gear 1 rotates for each order component.

Since the sound collector 9 is arranged to mainly collect noise generated by the differential gear 1, which is the object to be inspected or judged, order components appear conspicuously on the map. For example, in a three-dimensional map, the peaks representing sound pressure are lined up on a straight line showing the order, and in a two-dimensional map that shows sound pressure in color, points of a specific color or density are lined up on a straight line showing the order. It becomes a state. On the other hand, the sound collector 9 also collects background noise or environmental noise from the assembly line where the differential gear 1 is placed, so peaks or colors indicating the sound pressure of these noises appear on the map (see Figure 3). (Omitted in (A).) However, these peaks and colors are randomly scattered on the map and form the so-called background of the upward-sloping line indicating the order component above, and are different from the noise generated from differential gear 1. The difference is clear and can be distinguished.

Among the noises generated by differential gear 1, the noises that should be judged are those that can be heard by humans such as passengers in vehicles, and whose sound pressure is higher than other noises such as road noise and engine noise. It is a noise. Therefore, it is not necessary to use all the data on the map obtained as shown in FIG. Noise can be determined in a low rotational speed range where the noise is not noticeable. Therefore, the above-described determination device 10 includes a pickup section 16 that defines a high-order noise range determined by the rotation speed and frequency and extracts high-order components of the high-order noise range. FIG. 3B schematically shows the high-order noise range defined in this way. Since (B) in Fig. 3 is a so-called partial map taken out of a part of (A) in Fig. 3 mentioned above, it is a three-dimensional map with rotation speed, frequency, and sound pressure as coordinate axes. ing. Note that it is of course possible to use a two-dimensional map (color three-dimensional map) that expresses sound pressure using colors or shading. Furthermore, in FIG. 3B, sudden noises that are not related to the differential gear 1 are schematically shown with the symbol "Sr" attached thereto.

In order to determine the magnitude of sound pressure for each order component, the data in the above-mentioned high-order noise range is organized as a cumulative value of sound pressure for each order component, and the horizontal axis is plotted as shown in Figure 4. The order is converted into a graph in which the vertical axis is the sound pressure, and a plurality of (for example, 10) order components are extracted from the graph in descending order of the sound pressure. An extractor 17 is provided to perform this process. Note that the "order" in the embodiments of the present invention is not limited to an order obtained by multiplying a predetermined first-order component by an integer, but is an order with a vertical width. Therefore, when accumulating sound pressure, not only the sound pressure on the line rising to the right in FIG. Let be the cumulative value of sound pressure for . Since FIG. 4 is a graph extracted and created in this way, a predetermined "order component" shown on the horizontal axis is shown with a predetermined width.

After obtaining a plurality of order components having a large cumulative value of sound pressure as described above, a determination unit 18 is provided which makes a determination for each order component. This determination unit 18 is configured to determine whether the sound pressure level exceeds a predetermined determination reference value. In order to make this determination, the determination unit 18 determines tracking waveforms for a plurality of order components extracted in descending order of cumulative value of sound pressure. An example is shown in FIG. In FIG. 5, the horizontal axis shows the rotation speed, the vertical axis shows the sound pressure value, and the determination reference value is shown by a line with the symbol "T". If the sound pressure value is less than or equal to the determination reference value, it is determined to be "good", and if the sound pressure exceeds the determination reference value, it is determined to be "poor". The determination may be made by displaying it on the monitor 13 mentioned above or by outputting it from the printer 14, or by using the printed waveform shown in FIG. 5.

An example of the determination control executed by the determination device 10 having the above-described functional configuration, that is, a determination method as an embodiment of the present invention will be described as follows. FIG. 6 is a schematic flowchart for explaining one example. First, noise is taken in (step S1). The noise is acoustic data collected by the sound collector 9 described above. Additionally, the rotational speed detected by the sensor 11 described above is also taken in (step S2). NV measurement processing is performed using these data and time data (step S3). That is, sound pressure organized by frequency, rotation speed, and order is obtained, and tracking processing is performed using this (step S4). An example of the map obtained in this way is the map shown in FIG. 3A described above.

Next, a high-order noise range is picked up (step S5). For example, in the case of the differential gear 1 for a hybrid vehicle, the rotation speed range is such that the upper limit is the rotation speed corresponding to the vehicle speed at which the engine 8 is started, and the lower limit is the rotation speed corresponding to a predetermined low vehicle speed. . Further, the frequency range is within the audible range and is an empirically determined range that is thought to give a so-called discomfort.

The cumulative value of the sound pressure is determined for the order components in the high-order noise range (step S6). Since there are few order components included in the high-order noise range, the cumulative value of sound pressure may be calculated for order components that are integral multiples of the first-order component included in the high-order noise range, or for order components with a high sound pressure peak. The cumulative value of the sound pressure may be determined for A plurality of order components are extracted in descending order of the cumulative value thus determined (step S7). An example of the resulting waveform diagram is shown in FIG. 4 described above. Then, a determination is made by comparing the sound pressure of the extracted plurality of order components with a determination reference value (step S8).

The noise captured in step S1 described above may include noise as background noise or environmental noise collected by the sound collector 9, but this is only noise superimposed on a predetermined order component, and is not a so-called disturbance. Since all of the noise that occurs is not captured, there is almost no effect from sudden noise. Furthermore, in the embodiment of the present invention, the sound pressure value used for determination is the accumulated sound pressure for each order component, so it does not include a lot of sudden noise or be greatly affected. do not have. Therefore, according to the embodiments of the present invention, it is possible to determine gear noise without being influenced by background noise or environmental noise, which is a so-called disturbance. On the other hand, in the embodiment of the present invention described above, since the noise within the high-order noise range defined by the rotation speed and frequency is determined by calculating the cumulative value of the sound pressure described above, multiple occurrences occur, and the order It is possible to reliably grasp and judge changing high-order gear noise.

Note that the present invention is not limited to the embodiments described above, and the maps and waveform graphs described above are essentially visualizations of data, such as lists of numerical values and appropriate geometric shapes, etc. It may be a visualization of a shape or form other than those shown in . Further, in the present invention, the gear is not limited to a differential gear, but may be any appropriate gear that transmits power and rotates while meshing with each other.

1 Differential gear 2 Side gear 3 Differential case 4 Pinion gear 5 Ring gear 6 Hybrid drive device 7 Drive gear 8 Engine 9 Sound collector 10 Judgment device 11 Sensor 12 Operation section 13 Monitor 14 Printer 15 Tracking processing section 16 Pick-up section 17 Extraction section 18 Judgment section

Claims (2)

A high-order gear noise determination method for determining noise generated when gears mesh with each other and rotate,
Collects the noise generated from the gear,
Tracking the collected noise to create a map with rotation speed, frequency, and sound pressure as parameters,
Defining a high-order noise range of a predetermined rotation speed and frequency in the map,
In the high-order noise range, obtain a cumulative value of sound pressure for noise of a plurality of order components whose sound pressure is high, and extract a plurality of order components in descending order of the cumulative value,
A high-order gear noise determination method, comprising determining whether the sound pressure in each of the plurality of extracted order components exceeds a predetermined determination reference value. A high-order gear noise determination device that determines noise generated when gears mesh with each other and rotate,
a sound collector that collects noise generated from the gear;
a tracking processing unit that performs tracking processing on the collected noise and outputs a map with rotation speed, frequency, and sound pressure as parameters;
a pickup section that defines a high-order noise range of a predetermined rotation speed and frequency in the map;
an extraction unit that calculates a cumulative value of sound pressure for noise of a plurality of order components having high sound pressures in the high-order noise range, and extracts a plurality of order components in order of increasing cumulative value;
A high-order gear noise determination device comprising: a determination unit that determines whether the sound pressure in each of the plurality of extracted order components exceeds a predetermined determination reference value.

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