Part vibration testing method for mechanical part machining

Abstract

The invention relates to the technical field of vibration testing of structural components, in particular to a part vibration testing method for mechanical part machining, which comprises the following steps of: acquiring the rotation frequency and the tooth number of each gear, a box body vibration time domain waveform image and a difference value envelope line corresponding to the box body vibration time domain waveform image; the probability that the difference envelope line of each gear in each rotation period meets periodicity and the abnormal performance degree of each gear are calculated; a plurality of insertion points are selected on the difference envelope line of each meshing period of each gear, and the updating probability that each gear has swash vibration in each meshing period in each rotation period and the final abnormal performance degree of each gear are obtained; and a plurality of eccentric gears are further screened out from all the gears. According to the method, the impact oscillation caused by external factors to the normal gear is subjected to characteristic analysis, and the influence of the impact oscillation of the normal gear to the abnormal performance degree of the gear is eliminated. And the accuracy of gear detection is improved.

Description

Technical Field

[0001] The invention relates to the technical field of vibration testing of structural components, and in particular to a part vibration testing method for machining mechanical parts. Background Art

[0002] Gears are mechanical parts with teeth that can transmit power, change the speed and direction of movement, and mesh with each other. They are widely used in mechanical transmission and the entire mechanical field. In some fields, such as transportation tools such as airplanes and ships, the accuracy requirements for gears are extremely high, so the accuracy detection in the gear production process must be very strict. For the eccentricity defect of gears, in the prior art, defect detection is often performed by measuring the vibration waveform image of the gear vibration. The detection results are often interfered by external factors, such as the sudden shaking of the gear support structure, the temperature change of the working environment, etc. The vibration characteristics are similar to the vibration characteristics of the eccentric gear, resulting in the identification of normal qualified gears as eccentric gears, which reduces the accuracy of the detection. Summary of the invention

[0003] The invention provides a part vibration testing method for mechanical part processing to solve the existing problems.

[0004] A part vibration testing method for mechanical parts processing of the present invention adopts the following technical solution:

[0005] An embodiment of the present invention provides a part vibration testing method for mechanical part processing, the method comprising the following steps:

[0006] Obtain the rotation frequency and number of teeth of each gear and the time-domain waveform image of the box vibration; the horizontal and vertical axes of the time-domain waveform image of the box vibration are time and amplitude respectively;

[0007] According to the rotation frequency and number of teeth of each gear, the meshing period and rotation period of each gear are obtained;

[0008] Obtain the difference envelope corresponding to the housing vibration time domain waveform image of each gear; use the meshing period and rotation period of each gear to equally divide the difference envelope, and obtain the probability that the difference envelope of each gear satisfies the periodicity in each rotation period according to the amplitude and integral value of the difference envelope in all meshing periods of each gear in each rotation period; obtain the degree of abnormal performance of each gear according to the probability that the difference envelope of each gear satisfies the periodicity in each rotation period, the rotation period, the meshing period, and the amplitude of the difference envelope in each meshing period in each rotation period;

[0009] A number of interpolation points are selected at equal time intervals on the difference envelope line of each meshing cycle of each gear. According to the tangent slope of each interpolation point on the difference envelope line of each meshing cycle of each gear within each rotation cycle and the number of interpolation points, the updated probability of impulse vibration in each meshing cycle of each gear within each rotation cycle is obtained; according to the degree of abnormal performance, rotation cycle, meshing cycle of each gear, and the updated probability of impulse vibration in each meshing cycle of each gear within each rotation cycle, the final degree of abnormal performance of each gear is obtained.

[0010] According to the final degree of abnormal performance of each gear, several eccentric gears are screened out from all gears.

[0011] Further, the obtaining of the meshing cycle and rotation cycle of each gear according to the rotational frequency and number of teeth of each gear includes the following specific steps:

[0012] Denote the product of the rotational frequency and the number of teeth of the i-th gear as the meshing frequency of the i-th gear;

[0013] Denote the reciprocal of the meshing frequency of the i-th gear as the meshing cycle of the i-th gear;

[0014] Denote the reciprocal of the rotational frequency of the i-th gear as the rotation cycle of the i-th gear.

[0015] Further, the obtaining of the probability that the difference envelope line of each gear satisfies periodicity within each rotation cycle according to the amplitude magnitude and definite integral value magnitude of the difference envelope line in all meshing cycles of each gear within each rotation cycle includes the following specific steps:

[0016] Denote the variance of the difference between the maximum amplitude and the minimum amplitude of the difference envelope line in all meshing cycles of the z-th rotation cycle of the i-th gear as the amplitude threshold of the z-th rotation cycle of the i-th gear;

[0017] Denote the variance of the definite integral value of the difference envelope line in all meshing cycles of the z-th rotation cycle of the i-th gear as the definite integral threshold of the z-th rotation cycle of the i-th gear;

[0018] According to the amplitude threshold and definite integral threshold of each gear within each rotation cycle, obtain the probability that the difference envelope line of each gear satisfies periodicity within each rotation cycle.

[0019] Further, the obtaining of the probability that the difference envelope line of each gear satisfies periodicity within each rotation cycle according to the amplitude threshold and definite integral threshold of each gear within each rotation cycle includes the following specific steps:

[0020] Denote the amplitude threshold S of the i-th gear in the z-th rotation cycle i,zThe reciprocal of the definite integral threshold J of the i-th gear in the z-th rotation period i,z The product of the reciprocal and the probability that the difference envelope line of the i-th gear in the z-th rotation period satisfies periodicity is denoted as the probability that the difference envelope line of the i-th gear in the z-th rotation period satisfies periodicity.

[0021] Further, obtaining the abnormal performance degree of each gear according to the probability that the difference envelope line of each gear in each rotation period satisfies periodicity, the rotation period, the meshing period, and the amplitude of the difference envelope line in each meshing period within each rotation period includes the following specific steps:

[0022] Obtain the difference F between the maximum amplitude and the minimum amplitude of the difference envelope line in the j-th meshing period within the z-th rotation period of the i-th gear i,z,j , calculate the sum of the differences between the maximum amplitude and the minimum amplitude of the difference envelope line in all meshing periods within the z-th rotation period of the i-th gear, and denote the ratio of the sum of the differences to the probability that the difference envelope line of the i-th gear in the z-th rotation period satisfies periodicity as the first ratio of the i-th gear in the z-th rotation period, and denote the sum of the first ratios of the i-th gear in all rotation periods as the abnormal performance degree of the i-th gear.

[0023] Further, obtaining the updated probability of impulsive vibration in each meshing period within each rotation period of each gear according to the tangent slope of each insertion point on the difference envelope line of each meshing period within each rotation period of each gear and the number of insertion points includes the following specific steps:

[0024] Obtain the probability of impulsive vibration in each meshing period within each rotation period of each gear according to the tangent slope of each insertion point on the difference envelope line of each meshing period within each rotation period of each gear and the number of insertion points;

[0025] Denote the variance of the probability of impulsive vibration in the x-th meshing period of the i-th gear in all rotation periods as the probability threshold of the x-th meshing period of the i-th gear in all rotation periods;

[0026] Obtain the updated probability of impulsive vibration in each meshing period within each rotation period of each gear according to the probability of impulsive vibration in each meshing period within each rotation period of each gear and the probability threshold of each meshing period of each gear in all rotation periods.

[0027] Further, obtaining the probability of impulsive vibration in each meshing period within each rotation period of each gear according to the tangent slope of each insertion point on the difference envelope line of each meshing period within each rotation period of each gear and the number of insertion points includes the following specific steps:

[0028] Obtain the absolute value of the tangent slope of the y-th insertion point on the difference envelope line of the x-th meshing cycle within the z-th rotation cycle of the i-th gear, and calculate the average value of the absolute values of the tangent slopes of all insertion points on the difference envelope line of the x-th meshing cycle within the z-th rotation cycle of the i-th gear, which is used as the probability of impact vibration within the x-th meshing cycle of the i-th gear within the z-th rotation cycle.

[0029] Furthermore, it is characterized in that obtaining the updated probability of impact vibration within each meshing cycle of each gear within each rotation cycle according to the probability of impact vibration within each meshing cycle of each gear within each rotation cycle and the probability threshold of each meshing cycle of each gear in all rotation cycles includes the following specific steps:

[0030] Denote the product of the probability of impact vibration within the x-th meshing cycle of the i-th gear within the z-th rotation cycle and the probability threshold of the x-th meshing cycle of the i-th gear in all rotation cycles as the updated probability of impact vibration within the x-th meshing cycle of the i-th gear within the z-th rotation cycle.

[0031] Furthermore, obtaining the final abnormal performance degree of each gear according to the abnormal performance degree, rotation cycle, meshing cycle of each gear, and the updated probability of impact vibration within each meshing cycle of each gear within each rotation cycle includes the following specific steps:

[0032] Obtain the sum value of the updated probabilities of impact vibration within all meshing cycles of the i-th gear in all rotation cycles, and use the normalized value of the ratio of the abnormal performance degree of the i-th gear to the sum value as the final abnormal performance degree of the i-th gear.

[0033] Furthermore, screening out several eccentric gears from all gears according to the final abnormal performance degree of each gear includes the following specific steps:

[0034] Mark the gears with the final abnormal performance degree greater than the preset judgment threshold as eccentric gears.

[0035] The beneficial effects of the technical solution of the present invention are:

[0036] In an embodiment of the present invention, the rotational frequency and number of teeth of each gear are obtained, as well as the time-domain waveform image of the housing vibration; the horizontal and vertical axes of the time-domain waveform image of the housing vibration are time and amplitude respectively; according to the rotational frequency and number of teeth of each gear, the meshing period and rotation period of each gear are obtained; through the analysis of the rotational frequency and number of teeth of each gear, the meshing period and rotation period of each gear are calculated, providing data support for subsequent detection of whether there are defects in the gears. The difference envelope corresponding to the time-domain waveform image of the housing vibration of each gear is obtained; the difference envelope is equally divided by using the meshing period and rotation period of each gear respectively, and according to the amplitude magnitude and definite integral value magnitude of the difference envelope in all meshing periods in each rotation period of each gear, the probability that the difference envelope satisfies periodicity in each rotation period of each gear is obtained; according to the probability that the difference envelope satisfies periodicity in each rotation period of each gear, the rotation period, the meshing period, and the amplitude magnitude of the difference envelope in each meshing period in each rotation period, the degree of abnormal performance of each gear is obtained; through the probability that the difference envelope satisfies periodicity, the running stability and consistency of the gear can be evaluated, and combined with the rotation period, the meshing period, and the amplitude magnitude of the difference envelope in each meshing period, the degree of abnormal performance of the gear can be comprehensively evaluated, better reflecting the actual running condition of the gear. A number of interpolation points are selected at equal time intervals on the difference envelope of each meshing period of each gear, and according to the tangent slope of each interpolation point and the number of interpolation points on the difference envelope of each meshing period in each rotation period of each gear, the updated probability of impulsive vibration in each meshing period in each rotation period of each gear is obtained; according to the degree of abnormal performance of each gear, the rotation period, the meshing period, and the updated probability of impulsive vibration in each meshing period in each rotation period of each gear, the final degree of abnormal performance of each gear is obtained; through the analysis of the tangent slope of each interpolation point, the vibration condition of the gear during meshing can be analyzed more precisely, and through the analysis of the updated probability of impulsive vibration in each meshing period of each gear, the accuracy of abnormal gear detection is further improved. According to the final degree of abnormal performance of each gear, several eccentric gears are selected from all the gears. Thus, through the characteristic analysis of the impact and shock caused by external factors on normal gears, the influence of the impact and shock of normal gears on the degree of abnormal performance of gears is excluded. The accuracy of gear detection is improved. Description of the Drawings

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0038] Figure 1 This is a flowchart of the steps of a method for testing the vibration of parts for machining mechanical parts according to the present invention;

[0039] Figure 2 This is a diagram of the experimental device;

[0040] Figure 3 This is the time-domain waveform image of the box body vibration. Specific embodiments

[0041] In order to further elaborate on the technical means and effects adopted by the present invention to achieve the intended invention purpose, the following, in combination with the accompanying drawings and preferred embodiments, details the specific embodiments, structures, features and effects of a method for testing the vibration of parts for machining mechanical parts according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. In addition, the specific features, structures or characteristics in one or more embodiments can be combined in any suitable form.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs.

[0043] The following specifically describes the specific solution of a method for testing the vibration of parts for machining mechanical parts provided by the present invention with reference to the accompanying drawings.

[0044] Please refer to Figure 1 , which shows a flowchart of the steps of a method for testing the vibration of parts for machining mechanical parts provided by an embodiment of the present invention. The method includes the following steps:

[0045] Step S001: Obtain the rotational frequency and number of teeth of each gear and the time-domain waveform image of the box body vibration; the horizontal and vertical axes of the time-domain waveform image of the box body vibration are time and amplitude respectively.

[0046] Build a gear vibration test bench. Measure the rotational frequency and number of teeth of each gear.

[0047] Within a preset time period, obtain the vibration data of each gear and draw the time-domain waveform image of the box body vibration.

[0048] It should be noted that: Figure 2 This is the diagram of the experimental device in this embodiment, Figure 2 In, device 1 is the drive motor, device 2 is the coupling, device 3 is the test gearbox, device 4 is the vibration sensor, and device 5 is the loading motor. The preset time period is 10 minutes, and the acquisition frequency is once every 2 seconds. This is used as an example for description.

[0049] Step S002: Obtain the meshing period and rotation period of each gear based on the rotational frequency and number of teeth of each gear.

[0050] Taking the i-th gear as an example, the calculation formula for the meshing frequency of the i-th gear is:

[0051] fm i = f1 i × Z1 i

[0052] where, fm i is the meshing frequency of the i-th gear, f1 i is the rotational frequency of the i-th gear, and Z1 i is the number of teeth of the i-th gear.

[0053] Denote the reciprocal of the meshing frequency of the i-th gear as the meshing period of the i-th gear.

[0054] Denote the reciprocal of the rotational frequency of the i-th gear as the rotation period of the i-th gear.

[0055] Map the rotation period and meshing period to the time-domain waveform image of the housing vibration, and divide the time-domain waveform image of the housing vibration.

[0056] It should be noted that: Figure 3 For the time-domain waveform image of the housing vibration in this embodiment, the horizontal axis represents time and the vertical axis represents amplitude. The meshing frequencies of two meshing gears are equal.

[0057] Step S003: Obtain the differential envelope corresponding to the time-domain waveform image of the housing vibration of each gear; equally divide the differential envelope using the meshing period and rotation period of each gear respectively, and obtain the probability that the differential envelope satisfies periodicity in all meshing periods within each rotation period of each gear according to the amplitude magnitude and definite integral value magnitude of the differential envelope; obtain the abnormal performance degree of each gear according to the probability that the differential envelope satisfies periodicity within each rotation period of each gear, the rotation period, the meshing period, and the amplitude magnitude of the differential envelope within each meshing period within each rotation period.

[0058] Within the same rotation period, during the rotation of normal gears, the gear meshing degree is relatively moderate, the transmission torque between them is more uniform, and the impact and unbalanced force during meshing are smaller, thus reducing the vibration level of the gear system. For eccentric gears, when the gear teeth far from the center of the circle mesh and when the gear teeth close to the center of the circle mesh, it may lead to uneven distribution of the transmission torque, increasing the vibration and noise of the gear system.

[0059] Therefore, when normal gears are meshing, it is manifested in the time-domain waveform image of the housing vibration as a relatively uniform periodic change, and the amplitudes of different meshing cycles within the same rotation period are relatively similar; while when abnormal gears are meshing, due to the relatively chaotic vibration, it is manifested in the time-domain waveform image of the housing vibration as an unclear periodic change, and the amplitude changes of different meshing cycles within the same rotation period are relatively obvious.

[0060] Use the locally linear regression algorithm to extract the upper and lower envelopes in the time-domain waveform image of the housing vibration, calculate the difference between the upper and lower envelopes, and obtain the difference envelope of each gear.

[0061] It should be noted that: due to the influence of other factors in the time-domain waveform image of the housing vibration, it is difficult to analyze in the time-domain waveform image of the housing vibration. Therefore, draw the upper and lower envelopes of the image in the time-domain waveform image of the housing vibration, then calculate the difference between the upper and lower envelopes, and use the difference envelope to reflect whether the amplitude of the housing vibration exceeds a certain range. If it is a normal gear, the upper and lower envelopes both have good symmetry and periodicity, approaching a sine curve, then the difference envelope also approaches a sine curve. Therefore, the difference envelope of a normal gear has good periodicity; while for an eccentric gear, the periodicity of the upper and lower envelopes is poor. Therefore, according to the periodicity of the difference envelope, reflect the degree of abnormal performance of the gear. Among them, the locally linear regression algorithm is a well-known technology, which fits a local linear model according to the local data points of the input variables.

[0062] The definition of the periodicity of the difference envelope is that within each rotation period, the smaller the difference between the maximum amplitude and the minimum amplitude in different meshing cycles, the smaller the amplitude change, and the more it meets the periodicity of the difference envelope; and within different meshing cycles of each rotation period, the smaller the difference in the definite integral value of the difference envelope, the better the periodicity of the difference envelope.

[0063] Taking the i-th gear as an example, divide the difference envelope of the i-th gear equally by the meshing period and the rotation period of the i-th gear respectively. Denote the variance of the difference between the maximum amplitude and the minimum amplitude of the difference envelope in all meshing cycles in the z-th rotation period of the i-th gear as the amplitude threshold of the z-th rotation period of the i-th gear.

[0064] Denote the variance of the definite integral value of the difference envelope in all meshing cycles in the z-th rotation period of the i-th gear as the definite integral threshold of the z-th rotation period of the i-th gear.

[0065] Denote the reciprocal of the amplitude threshold S i,z of the i-th gear in the z-th rotation period and the definite integral threshold J i,zThe product of the reciprocals is denoted as the probability that the difference envelope of the i-th gear in the z-th rotation period satisfies periodicity.

[0066] Taking the i-th gear as an example, the calculation formula for the probability that the difference envelope of the i-th gear in the z-th rotation period satisfies periodicity is:

[0067]

[0068] Among them, E i,z represents the probability that the difference envelope of the i-th gear in the z-th rotation period satisfies periodicity, S i,z is the amplitude threshold of the i-th gear in the z-th rotation period, and J i,z is the definite integral threshold of the i-th gear in the z-th rotation period.

[0069] It should be noted that: S i,z is the amplitude threshold of the i-th gear in the z-th rotation period, which represents the magnitude of the difference in the amplitudes of the difference envelopes between different meshing periods of the i-th gear in the z-th rotation period. The smaller the amplitude difference, the more the difference envelope between different meshing periods of the i-th gear in the z-th rotation period satisfies periodicity. J i,z is the definite integral threshold of the i-th gear in the z-th rotation period, which represents the definite integral difference between different meshing periods of the i-th gear in the z-th rotation period. The smaller the definite integral difference, the more the difference envelope between different meshing periods of the i-th gear in the z-th rotation period satisfies periodicity. E i,z represents the probability that the difference envelope of the i-th gear in the z-th rotation period satisfies periodicity. The larger the probability, the smaller the abnormal performance degree of the i-th gear, the more it satisfies the vibration characteristics of a normal gear, and the greater the probability that the i-th gear is a normal gear. In this embodiment, when the denominator in the formula is 0, the denominator is set to 1 to prevent the denominator from being 0, and this is used as an example for description.

[0070] In the above manner, this embodiment can obtain the probability that the difference envelope of each gear satisfies periodicity in all rotation periods.

[0071] In addition, the amplitude of the difference envelope of the i-th gear between different meshing periods in the same rotation period can also effectively reflect the abnormal performance degree of the i-th gear. The larger the amplitude of the difference envelope, the greater the probability of obvious vibration in the time-domain waveform image of the box body vibration, and the greater the abnormal performance degree of the i-th gear.

[0072] Obtain the difference F between the maximum amplitude and the minimum amplitude of the difference envelope in the j-th meshing period of the i-th gear in the z-th rotation period i,z,j, calculate the sum of the differences between the maximum amplitude and the minimum amplitude of the difference envelope in all meshing cycles of the i-th gear during the z-th rotation cycle, and denote the ratio of the sum of the differences to the probability that the difference envelope of the i-th gear satisfies periodicity during the z-th rotation cycle as the first ratio of the i-th gear during the z-th rotation cycle. Denote the sum of the first ratios of the i-th gear in all rotation cycles as the degree of abnormal performance of the i-th gear.

[0073] Taking the i-th gear as an example, the calculation formula for the degree of abnormal performance of the i-th gear is as follows:

[0074]

[0075] where p i represents the degree of abnormal performance of the i-th gear, and E i,z represents the probability that the difference envelope of the i-th gear satisfies periodicity during the z-th rotation cycle, and C i represents the number of meshing cycles of the i-th gear in each rotation cycle, and F i,z,j represents the difference between the maximum amplitude and the minimum amplitude of the difference envelope in the j-th meshing cycle of the i-th gear during the z-th rotation cycle, and M i represents the number of rotation cycles of the i-th gear.

[0076] It should be noted that: represents the sum of the differences between the maximum amplitude and the minimum amplitude of the difference envelope in all meshing cycles of the i-th gear during the z-th rotation cycle. The larger the sum value, the worse the periodicity of the difference envelope, and the greater the degree of abnormal performance of the i-th gear. In this embodiment, when the denominator in the formula is 0, let the denominator be 1 to prevent the denominator from being 0, and this is used as an example for description.

[0077] In the above manner, the degree of abnormal performance of each gear can be obtained in this embodiment.

[0078] Step S004: Select a number of interpolation points at equal time intervals on the difference envelope of each meshing cycle of each gear. According to the tangent slope of each interpolation point and the number of interpolation points on the difference envelope of each meshing cycle of each gear in each rotation cycle of each gear, obtain the updated probability of impulsive vibration in each meshing cycle of each gear in each rotation cycle. According to the degree of abnormal performance, rotation cycle, meshing cycle of each gear, and the updated probability of impulsive vibration in each meshing cycle of each gear in each rotation cycle of each gear, obtain the final degree of abnormal performance of each gear.

[0079] Due to external environmental factors, such as sudden vibrations of the gear support structure, temperature changes in the working environment, etc., gear shock vibrations may occur. The definition of gear shock vibrations is a sudden and significant change in the vibration level of the gear. In the time-domain waveform image of the housing vibration, it is manifested as a sudden increase in the vibration amplitude, which suddenly disappears within a short period. Just calculating based on the above characteristics, the calculated abnormal performance degree of the gear is relatively large, exceeding the normal range of gear abnormal performance degree, resulting in misidentifying a normal gear as an eccentric gear. Therefore, this situation needs to be excluded.

[0080] Regarding the shock vibrations of normal gears, different from the vibration characteristics caused by eccentric gears, the shock vibrations of normal gears experience a shorter time and a greater vibration level. Therefore, on the difference envelope line, within a certain meshing cycle, the steeper the waveform, the greater the probability that the shock in this meshing cycle is a shock vibration, and the smaller the probability that the gear is an abnormal gear. At the same time, in different rotation cycles, the greater the change in the waveform steepness of the same meshing cycle, the greater the probability that the shock is a shock vibration.

[0081] Within each meshing cycle, for calculating the steepness of the difference envelope line, several points are selected by equally dividing the horizontal axis of the time-domain waveform image of the housing vibration for each meshing cycle, and the slope values of the difference envelope line corresponding to these points are calculated. The greater the absolute value of these slopes, the greater the probability that the shock in this meshing cycle is a shock vibration. The number of equally divided points cannot be too many, as it will lead to excessive calculation amount and reduce the calculation efficiency, nor can it be too few, otherwise it will lose its reference value.

[0082] On the difference envelope line of the x-th meshing cycle of the i-th gear, h points are selected at equal time intervals, and these points are recorded as insertion points. Calculate the tangent slopes of these points.

[0083] It should be noted that: in this embodiment, the preset quantity threshold h is 5. When the number of insertion points is insufficient or exceeds 5, the analysis is carried out based on the actual number of insertion points, and this is used as an example for description.

[0084] Obtain the absolute value of the tangent slope of the y-th insertion point on the difference envelope line of the x-th meshing cycle of the i-th gear within the z-th rotation cycle of the i-th gear, and calculate the average value of the absolute values of the tangent slopes of all insertion points on the difference envelope line of the x-th meshing cycle of the i-th gear within the z-th rotation cycle of the i-th gear, as the probability of the i-th gear having shock vibrations within the x-th meshing cycle of the z-th rotation cycle.

[0085] Taking the i-th gear as an example, the calculation formula for the probability of the i-th gear having shock vibrations within the x-th meshing cycle of the z-th rotation cycle is:

[0086]

[0087] where r i,z,x represents the probability that the i-th gear has impact vibration during the x-th meshing cycle within the z-th rotation period, k i,z,x,y represents the tangent slope of the y-th insertion point on the difference envelope line of the x-th meshing cycle within the z-th rotation period of the i-th gear, H i,z,x represents the number of insertion points during the x-th meshing cycle within the z-th rotation period of the i-th gear, and || represents the absolute value function.

[0088] It should be noted that: represents the mean value of the absolute values of the tangent slopes of all insertion points during the x-th meshing cycle within the z-th rotation period of the i-th gear. The larger the mean value, the steeper the waveform of the difference envelope line of the i-th gear during the x-th meshing cycle, and the greater the probability of having impact vibration during this meshing cycle. In this embodiment, when the denominator in the formula is 0, the denominator is set to 1 to prevent the denominator from being 0, and this is used as an example for description.

[0089] In the above manner, this embodiment can obtain the probability that each gear has impact vibration during all meshing cycles within each rotation period.

[0090] The variance of the probability that the i-th gear has impact vibration during the x-th meshing cycle in all rotation periods is denoted as the probability threshold of the x-th meshing cycle of the i-th gear in all rotation periods.

[0091] According to the change of the probability that the i-th gear has impact vibration during the x-th meshing cycle in all rotation periods, correct the probability that the gear has impact vibration during the x-th meshing cycle within the z-th rotation period.

[0092] Taking the i-th gear as an example, the calculation formula for the updated probability that the i-th gear has impact vibration during the x-th meshing cycle within the z-th rotation period is:

[0093] R i,z,x = r i,z,x × S i,x

[0094] where R i,z,x represents the updated probability that the i-th gear has impact vibration during the x-th meshing cycle within the x-th rotation period, r i,z,x represents the probability that the i-th gear has impact vibration during the x-th meshing cycle within the z-th rotation period, S i,x represents the probability threshold of the x-th meshing cycle of the i-th gear in all rotation periods.

[0095] It should be noted that: S i,xIt represents the probability threshold of the x-th meshing cycle of the i-th gear in all rotation cycles, combines the probability differences of the i-th gear having impact vibrations in the same meshing cycle within multiple rotation cycles, ensures the reference value of the probability of having impact vibrations in the x-th meshing cycle, and the greater the probability difference, the greater the updated probability of the i-th gear having impact vibrations in the x-th meshing cycle of the z-th rotation cycle. In this embodiment, when the denominator in the formula is 0, the denominator is set to 1 to prevent the denominator from being 0, and this is used as an example for description.

[0096] In the above manner, this embodiment can obtain the updated probabilities of each gear having impact vibrations in all meshing cycles within each rotation cycle.

[0097] Based on the updated probability of the i-th gear having impact vibrations in the x-th meshing cycle of the z-th rotation cycle, the abnormal performance degree of the i-th gear is corrected. In the same rotation cycle, the greater the updated probability of having impact vibrations in each meshing cycle, the greater the probability that the i-th gear is a normal gear, and vice versa.

[0098] Obtain the sum value of the updated probabilities of the i-th gear having impact vibrations in all meshing cycles within all rotation cycles, and use the normalized value of the ratio of the abnormal performance degree of the i-th gear to the sum value as the final abnormal performance degree of the i-th gear.

[0099] Taking the i-th gear as an example, the calculation formula for the final abnormal performance degree of the i-th gear is:

[0100]

[0101] Among them, p' i is the final abnormal performance degree of the i-th gear, p i represents the abnormal performance degree of the i-th gear, C i represents the number of meshing cycles of the i-th gear within each rotation cycle, R i,z,x represents the updated probability of the i-th gear having impact vibrations in the x-th meshing cycle of the z-th rotation cycle, M i represents the number of rotation cycles of the i-th gear, and norm() represents the linear normalization function.

[0102] It should be noted that: p i represents the abnormal performance degree of the i-th gear, but it is impossible to exclude the influence of the impact and vibration of normal gears on the abnormal performance degree of the gear. Therefore, by calculating the probability of having impact and vibration in the same rotation cycle, the influence of the impact and vibration of normal gears is excluded. It represents the sum of the updated probabilities of the impact vibration during all meshing cycles of the i-th gear in the z-th rotation cycle. Therefore, the smaller the probability of having impact vibration in a single rotation cycle, the smaller the interference of the impact shock on the abnormal performance degree of the gear, and thus the greater the abnormal performance degree of the gear. In this embodiment, when the denominator in the formula is 0, the denominator is set to 1 to prevent the denominator from being 0, and the following description is given by taking this as an example.

[0103] In the above manner, this embodiment can obtain the final abnormal performance degree of each gear.

[0104] Step S005: According to the final abnormal performance degree of each gear, several eccentric gears are screened out from all the gears.

[0105] A preset judgment threshold is set, and the gears with the final abnormal performance degree greater than the preset judgment threshold are marked as eccentric gears.

[0106] It should be noted that: In this embodiment, the preset judgment threshold is 0.9, and the following description is given by taking this as an example. All the detected eccentric gears are discarded, so as to improve the qualified rate in the gear production process.

[0107] So far, the present invention is completed.

[0108] In summary, in the embodiments of the present invention, the rotational frequency and number of teeth of each gear are obtained, as well as the time-domain waveform image of the housing vibration; the horizontal and vertical axes of the time-domain waveform image of the housing vibration are time and amplitude respectively; according to the rotational frequency and number of teeth of each gear, the meshing period and rotational period of each gear are obtained; the differential envelope corresponding to the time-domain waveform image of the housing vibration of each gear is obtained; the differential envelope is equally divided by using the meshing period and rotational period of each gear respectively, and according to the amplitude value and definite integral value of the differential envelope in all meshing periods of each gear in each rotational period, the probability that the differential envelope satisfies periodicity in each rotational period of each gear is obtained; according to the probability that the differential envelope satisfies periodicity in each rotational period of each gear, the rotational period, the meshing period, and the amplitude value of the differential envelope in each meshing period in each rotational period, the abnormal performance degree of each gear is obtained; several insertion points are selected at equal time intervals on the differential envelope of each meshing period of each gear, and according to the tangent slope of each insertion point and the number of insertion points on the differential envelope of each meshing period of each gear in each rotational period, the updated probability of impulsive vibration in each meshing period of each gear in each rotational period is obtained; according to the abnormal performance degree of each gear, the rotational period, the meshing period, and the updated probability of impulsive vibration in each meshing period of each gear in each rotational period, the final abnormal performance degree of each gear is obtained; according to the final abnormal performance degree of each gear, several eccentric gears are selected from all the gears. Thus, the present invention analyzes the characteristics of the impact and shock caused by external factors on normal gears, and excludes the influence of the impact and shock of normal gears on the abnormal performance degree of gears. The accuracy of gear detection is improved.

[0109] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the vibration of parts used in machining mechanical parts, characterized in that, The method includes the following steps: Obtain the rotational frequency and number of teeth of each gear, and the time-domain waveform image of the housing vibration; the horizontal and vertical axes of the time-domain waveform image of the housing vibration are time and amplitude respectively; According to the rotational frequency and number of teeth of each gear, obtain the meshing period and rotational period of each gear; Obtain the difference envelope corresponding to the time-domain waveform image of the housing vibration of each gear; use the meshing period and rotational period of each gear to equally divide the difference envelope respectively, and according to the amplitude value and definite integral value of the difference envelope in all meshing periods of each gear in each rotational period, obtain the probability that the difference envelope of each gear satisfies periodicity in each rotational period; according to the probability that the difference envelope of each gear satisfies periodicity in each rotational period, the rotational period, the meshing period, and the amplitude value of the difference envelope in each meshing period in each rotational period, obtain the abnormal performance degree of each gear; Select a number of interpolation points at equal time intervals on the difference envelope of each meshing period of each gear, and according to the tangent slope of each interpolation point and the number of interpolation points on the difference envelope of each meshing period of each gear in each rotational period, obtain the updated probability of impact vibration in each meshing period of each gear in each rotational period; according to the abnormal performance degree of each gear, the rotational period, the meshing period, and the updated probability of impact vibration in each meshing period of each gear in each rotational period, obtain the final abnormal performance degree of each gear; According to the final abnormal performance degree of each gear, screen out a number of eccentric gears from all gears.

2. The method for testing the vibration of parts for machining mechanical parts according to claim 1, characterized in that, The step of obtaining the meshing period and rotational period of each gear according to the rotational frequency and number of teeth of each gear includes the following specific steps: Denote the product of the rotational frequency and number of teeth of the i-th gear as the meshing frequency of the i-th gear; Denote the reciprocal of the meshing frequency of the i-th gear as the meshing period of the i-th gear; Denote the reciprocal of the rotational frequency of the i-th gear as the rotational period of the i-th gear.

3. A method for testing the vibration of parts for machining mechanical parts according to claim 1, characterized in that, The step of obtaining the probability that the difference envelope of each gear satisfies periodicity in each rotational period according to the amplitude value and definite integral value of the difference envelope in all meshing periods of each gear in each rotational period includes the following specific steps: Denote the variance of the difference between the maximum amplitude and the minimum amplitude of the difference envelope in all meshing periods of the z-th rotational period of the i-th gear as the amplitude threshold of the z-th rotational period of the i-th gear; Denote the variance of the definite integral value of the difference envelope in all meshing periods of the z-th rotational period of the i-th gear as the definite integral threshold of the z-th rotational period of the i-th gear; According to the amplitude threshold and definite integral threshold of each gear in each rotational period, obtain the probability that the difference envelope of each gear satisfies periodicity in each rotational period.

4. A method for testing the vibration of parts for machining mechanical parts according to claim 3, characterized in that, The step of obtaining the probability that the difference envelope of each gear satisfies periodicity in each rotational period according to the amplitude threshold and definite integral threshold of each gear in each rotational period includes the following specific steps: The reciprocal of the amplitude threshold S of the i-th gear in the z-th rotation period i,z multiplied by the reciprocal of the definite integral threshold J of the i-th gear in the z-th rotation period i,z is denoted as the probability that the differential envelope of the i-th gear in the z-th rotation period satisfies periodicity.

5. A method for testing the vibration of parts for machining mechanical parts according to claim 1, characterized in that, Obtaining the abnormal performance degree of each gear according to the probability that the difference envelope line satisfies periodicity in each rotation period of each gear, the rotation period, the meshing period, and the amplitude of the difference envelope line in each meshing period within each rotation period, including the following specific steps: Obtain the difference F between the maximum amplitude and the minimum amplitude of the difference envelope in the j-th meshing cycle during the z-th rotation period of the i-th gear i,z,j , calculate the sum of the differences between the maximum amplitude and the minimum amplitude of the difference envelope in all meshing cycles during the z-th rotation period of the i-th gear, and denote the ratio of the sum of the differences to the probability that the difference envelope of the i-th gear satisfies periodicity during the z-th rotation period as the first ratio of the i-th gear during the z-th rotation period. Denote the sum of the first ratios of the i-th gear during all rotation periods as the degree of abnormal performance of the i-th gear.

6. The method for testing the vibration of parts for machining mechanical parts according to claim 1, wherein Obtaining the updated probability of impact vibration in each meshing period within each rotation period of each gear according to the tangent slope of each insertion point on the difference envelope line in each meshing period within each rotation period of each gear and the number of insertion points, including the following specific steps: Obtaining the probability of impact vibration in each meshing period within each rotation period of each gear according to the tangent slope of each insertion point on the difference envelope line in each meshing period within each rotation period of each gear and the number of insertion points; Denoting the variance of the probability of impact vibration in the x-th meshing period of the i-th gear in all rotation periods as the probability threshold of the x-th meshing period of the i-th gear in all rotation periods; Obtaining the updated probability of impact vibration in each meshing period within each rotation period of each gear according to the probability of impact vibration in each meshing period within each rotation period of each gear and the probability threshold of each meshing period of each gear in all rotation periods.

7. A method for testing the vibration of parts used in the machining of mechanical parts according to claim 6, characterized in that, Obtaining the probability of impact vibration in each meshing period within each rotation period of each gear according to the tangent slope of each insertion point on the difference envelope line in each meshing period within each rotation period of each gear and the number of insertion points, including the following specific steps: Obtaining the absolute value of the tangent slope of the y-th insertion point on the difference envelope line in the x-th meshing period of the i-th gear in the z-th rotation period, and calculating the mean value of the absolute values of the tangent slopes of all insertion points on the difference envelope line in the x-th meshing period of the i-th gear in the z-th rotation period as the probability of impact vibration in the x-th meshing period of the i-th gear in the z-th rotation period.

8. A method for testing the vibration of parts for machining mechanical parts according to claim 6, characterized in that, Obtaining the updated probability of impact vibration in each meshing period within each rotation period of each gear according to the probability of impact vibration in each meshing period within each rotation period of each gear and the probability threshold of each meshing period of each gear in all rotation periods, including the following specific steps: Denoting the product of the probability of impact vibration in the x-th meshing period of the i-th gear in the z-th rotation period and the probability threshold of the x-th meshing period of the i-th gear in all rotation periods as the updated probability of impact vibration in the x-th meshing period of the i-th gear in the z-th rotation period.

9. The part vibration test method for machining mechanical parts according to claim 1, characterized in that According to the abnormal performance degree of each gear, the rotation period, the meshing period, and each gear within each rotation period of each meshing period with the updated probability of impact vibration, obtaining the final abnormal performance degree of each gear, including the following specific steps: Obtain the sum value of the updated probabilities of the impact vibration in all meshing cycles during all rotation cycles of the i-th gear, and use the normalized value of the ratio of the abnormal performance degree of the i-th gear to the sum value as the final abnormal performance degree of the i-th gear.

10. A method for testing the vibration of parts for machining mechanical parts according to claim 1, characterized in that, The specific steps for screening out a number of eccentric gears from all gears according to the final abnormal performance degree of each gear are as follows: Mark the gears with a final abnormal performance degree greater than the preset judgment threshold as eccentric gears.

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