Method and system for analyzing endogenous excitation load and vibration transmission of power transmission system

Abstract

The invention discloses a power transmission system internal source excitation load and vibration transmission analysis method and system. The method comprises the steps that firstly, gear dynamic meshing rigidity, spline equivalent bearing rigidity and a flexible shaft model are obtained based on parameters of a gear, a spline and a rotating shaft, and then a power transmission system vibration transmission analysis model is established by combining bearing parameters; the method comprises the following steps: respectively obtaining a vibration acceleration signal of each bearing seat position through experiments and simulation, extracting a signal corresponding to each meshing excitation from each bearing seat measuring point signal through a defined comb filter, and calculating the vibration energy contribution of each meshing excitation; finally, through meshing excitation vibration contribution of multiple measuring points and a load transmission rule among parts obtained through simulation, a transmission rule of endogenous excitation load and vibration in the power transmission system is disclosed, vibration characterization of each measuring point in the power transmission system can be accurately obtained based on the method, a theoretical basis is provided for selection of sensitive measuring points, and the method has a wide application prospect. Therefore, support is provided for digital twin modeling and health management of the power transmission system.

Description

Technical Field

[0001] The present invention belongs to the technical field of gear measurement, and in particular relates to a method and system for analyzing endogenous excitation load and vibration transmission of a power transmission system. Background Art

[0002] The power transmission system consists of components such as gears, splines, shafts, bearings and housings. It is usually used as a power conversion device in tracked vehicle engines, ship gearboxes and other equipment. Due to the poor service conditions of the power transmission system, transmission components frequently fail. Digital twin technology provides technical support for the health management of the power transmission system. The accurate establishment of the digital twin model depends on the real-time and accurate data interaction between the physical entity and the virtual model, while the acquisition of the physical entity state data of the power transmission system depends on the sensors on the bearing seat or housing. However, in engineering practice, the number of sensors installed is limited by location and economic factors. Selecting sensitive sensor measurement points to capture as much useful information as possible is an engineering problem that needs to be solved urgently. The theoretical basis for finding sensitive measurement points is the coupled vibration mechanism and vibration transmission law of the power transmission system, that is, to clarify the endogenous excitation characterization of each sensor monitoring position. Since there are multiple internal excitations and multiple coupled vibration transmission paths from the excitation source to the sensor measurement point, as well as nonlinear supports such as splines and bearings, the transmission law of the endogenous excitation is still unclear, which brings great challenges to the health management of the power transmission system.

[0003] At present, the methods used for the analysis of endogenous excitation transmission in power transmission systems mainly include the transfer path method and the power flow method. Among them, the transfer path analysis is a method for identifying energy transfer paths based on the superposition principle and experimental tests. It can be divided into classical, component-based and transmissibility-based transfer path analysis methods. Its core is to solve the transmissibility matrix by inverting the response signal, but it requires a lot of frequency response function testing work, and it is based on the linear assumption to study the time-invariant system. The power transmission system has the characteristics of strong nonlinear time variation, multiple vibration transmission paths and mutual coupling. Its time-varying frequency response function is difficult to measure accurately, so it is difficult to decouple and analyze its transmission path. The application of the power flow method in the power transmission system mainly includes evaluating the overall vibration of the system, determining the vibration contribution of different transmission paths in the transmission system, and revealing the transmission law of the transmission system. However, this method usually ignores the influence of non-continuous interfaces such as gears, bearings and splines on vibration transmission, and cannot accurately reveal the vibration transmission law of the coupled system. In the prior art, a Chinese invention patent with a patent application publication number of CN112035966A discloses a gear vibration source identification method based on gear intrinsic excitation force. However, this method is based on a sparse deconvolution model for solving dynamic transmission errors, and is mainly used to identify gear intrinsic excitation force, but does not involve vibration transmission of intrinsic excitation. Therefore, it is of great significance to propose a method that can accurately analyze the meshing excitation transmission of a power transmission system. Summary of the Invention

[0004] In order to solve the problems existing in the prior art, the present invention provides a method and system for analyzing the internal excitation load and vibration transmission of a power transmission system, which can accurately analyze the load and vibration transmission law of the internal excitation in the power transmission system.

[0005] In order to achieve the above object, on the one hand, the present invention provides a method for analyzing the internal excitation load and vibration transmission of a power transmission system, including the following steps: Define the transfer function of the comb filter based on the meshing frequency and sampling frequency of the power transmission system H ; Obtain the vibration acceleration signals at the positions of each bearing seat in the experiment and simulation, and respectively extract the signals of each meshing frequency component of the power transmission system from the obtained signals based on the comb filter; Based on the signals extracted by the comb filter, define the vibration energy contribution evaluation index CVE of the internal excitation, analyze the proportion of the vibration contribution of each internal excitation in the signals of each bearing seat, verify the correctness of the simulation model by comparing the simulation and experimental results, and calculate the load transmission law of the internal excitation between each transmission component through the simulation model, so as to reveal the transmission law of the internal excitation in the power transmission system.

[0006] Further, when defining the transfer function of the comb filter based on the meshing frequency and sampling frequency of the power transmission system H The meshing frequency of the power transmission system Is calculated by the product of the gear speed and the number of teeth, and there are multiple meshing frequency components in the power transmission system. The sampling frequency Is the number of sampling points per unit time, and the expression of the comb filter is:

[0007] Where Is a constant in the interval (0,1). Decreasing Value, the influence of the filter on other frequency signals increases, the frequency response curve becomes steeper, and the filtering effect is better. Represents the filtering order, and the filtering order for different meshing frequencies should be an integer, which is achieved by resampling the original signal.

[0008] Further, the internal excitation is the gear meshing excitation, and the vibration energy contribution evaluation index CVE is expressed as:

[0009] Where the subscript i Represents the i Th gear meshing excitation source, Represents thei The energy of the signal corresponding to a meshing frequency component It represents the number of meshing excitation sources included in the power transmission system. There are multiple meshing excitation sources in the signal measured at the same bearing pedestal. By calculating the CVE values of each meshing excitation, the vibration contribution characterization of the meshing excitation at this measurement point is revealed. By calculating the CVE values at the bearing pedestal positions corresponding to all gears and plotting them in the form of a bar chart, the coupling vibration mechanism of the power transmission system is visually represented. By comparing the experimental and simulation results, the correctness of the simulation model is verified. Based on the simulation dynamics model, the forces between each transmission component are output, the load transfer law of the internal source excitation between each transmission component is obtained, and finally the vibration characterization and transfer law of the internal source excitation in the entire power transmission system are revealed.

[0010] Furthermore, obtaining the vibration acceleration signals at the positions of each bearing pedestal in the simulation includes the following steps: Establish a gear dynamic meshing stiffness model based on gear parameters and the fast influence coefficient method; Obtain the equivalent support stiffness of the spline based on spline parameters and the gear-spline coupling model; Establish a flexible shaft model based on shaft parameters, and combine the gear dynamic meshing stiffness model, the equivalent support stiffness of the spline, and the equivalent support stiffness of the bearing to establish a vibration transfer analysis model of the power transmission system; Based on the vibration transfer analysis model of the power transmission system, the vibration accelerations at the positions of each bearing pedestal are obtained through simulation solution.

[0011] Furthermore, the above-mentioned gear parameters include the mass, moment of inertia, number of teeth, tooth width, module, and center hole radius of the gear. The fast influence coefficient method discretizes the contact area of the meshing tooth pair into several units, calculates the bending, axial compression, shear, Hertz contact, and fillet base deformation coefficients between each discrete unit based on the gear parameters and the position of the gear meshing point, and establishes an influence coefficient matrix. The gear dynamic meshing stiffness model first determines the clearance between the discrete units of the contacting tooth pair, and equivalent the gear dynamic transmission error to the elastic approach amount, and then combines the influence coefficient matrix to establish a clearance-deformation equation set, and obtains the gear dynamic meshing stiffness through iterative solution.

[0012] Furthermore, the above-mentioned spline parameters include the number of teeth, module, pressure angle, and tooth width, and the gear-spline coupling model considers the spline fit clearance; The establishment of the spline parameters and the gear-spline coupling model includes: first determining the position where the gear and the spline make initial contact, and setting the initial rotational speed, and then determining the change amount of the spline pair clearance sequence according to the direction of the meshing force, and establishing a gear-spline translation and torsion motion equation set, that is, the spline parameters and the gear-spline coupling model; The equivalent support stiffness of the spline is obtained by differentiating the relative displacement with respect to the acting force and acting moment between the internal spline and the external spline.

[0013] Furthermore, the shaft parameters include the mass, length, and moment of inertia of the shaft. The flexible shaft model is established by the rigid body element method, including: dividing the shaft into several rigid body elements, calculating the equivalent support stiffness between adjacent rigid body elements based on the shaft parameters and the theory of mechanics of materials, establishing the dynamic equations of each rigid body element in the translational direction based on Newton's equations, and establishing the dynamic equations of each rigid body element in the torsional direction based on Euler's equations. The established equations are the flexible shaft model. Furthermore, establishing a vibration transfer analysis model of the power transmission system by combining the gear dynamic mesh stiffness model, the equivalent support stiffness of the spline, and the equivalent support stiffness of the bearing includes: assuming the bearing as a spring-damper structure for the equivalent support stiffness of the bearing. The vibration transfer analysis model of the power transmission system is based on the flexible shaft model. Converting the gear dynamic mesh stiffness into a dynamic meshing force and introducing it into the flexible shaft dynamic equations. Equivalent the spline to a support stiffness and a support damper, calculate the spline support force by combining the relative displacement and relative velocity between the gear and the shaft unit connected by the spline. Equivalent the bearing to a support stiffness and a support damper, calculate the bearing support force by combining the relative displacement and relative velocity between the bearing outer ring and the shaft unit connected by the bearing, and obtain the vibration transfer analysis model of the power transmission system.

[0014] Furthermore, in the experiment, the parameters of the vibration transfer analysis test bench of the power transmission system are consistent with the parameters of the simulation model. The vibration acceleration signals collected at each bearing housing in the experiment contain various meshing frequency components and noise components. Using the comb-shaped filter to perform comb-shaped filtering on the experimental signals, and finally extracting the signals of each frequency component from the experimental signals. For the vibration acceleration signals at the positions of each bearing housing obtained by simulation, the signals of each frequency component are also extracted using the comb-shaped filter.

[0015] On the other hand, based on the concept of the method, the present invention provides a system for analyzing the internal excitation load and vibration transfer of a power transmission system, including a comb-shaped filter establishment and solution module, a vibration energy contribution evaluation index establishment module, and a solution module. The comb-shaped filter establishment and solution module is used to establish the transfer function of the comb-shaped filter H and obtain signals that can be filtered by an integer-order comb-shaped filter by resampling the signals. Then, perform comb-shaped filtering on the signals at the positions of the bearing housings obtained from the experiment and simulation respectively, and extract the signals of each meshing frequency component. The vibration energy contribution evaluation index establishment module and the solution module are used to establish the vibration energy contribution evaluation index CVE, solve the CVE values of the signals at the positions of the bearing housings corresponding to all gears in the power transmission system, draw a bar chart of the vibration contributions at each measurement point of the power transmission system, and output the acting forces between each transmission component.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The present invention proposes an analysis method for internal excitation load and vibration transmission of a power transmission system. By separately establishing a gear dynamic meshing stiffness model and a flexible shaft model, and calculating the equivalent support stiffness of splines, a vibration transmission analysis model of the power transmission system is obtained. By using the defined comb filter to extract the signals corresponding to each meshing excitation from the signals of each measuring point, and calculating the proportion of the vibration contribution energy of each meshing excitation, finally, the transmission law of the meshing excitation in the power transmission system is revealed through the vibration contribution evaluation index of multiple measuring points. The present invention makes full use of the advantage of the comb filter to extract periodic signals, accurately establishes a vibration transmission analysis model of the power transmission system, obtains the load transmission law between each transmission component, and has the advantage of high accuracy. The vibration transmission analysis model and vibration contribution evaluation index of the power transmission system established by using this method can accurately reveal the transmission law of internal excitation in the power transmission system, provide a theoretical basis for the selection of its sensitive measuring points, and thus provide support for the digital twin modeling and health management of the power transmission system. Description of the Drawings

[0017] Figure 1 is the flow chart of the analysis method and system for internal excitation load and vibration transmission of the power transmission system provided by the present invention.

[0018] Figure 2 is an embodiment disclosed by the present invention, a vibration transmission analysis model of a power transmission system.

[0019] Figure 3 is a schematic diagram of signal filtering using a comb filter.

[0020] Figure 4 is the result of the proportion of the vibration contribution of each meshing excitation in the bearing seat signal. Detailed Embodiments

[0021] The following will elaborate on the present invention in conjunction with the attached Figures 1-4 Although specific embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art.

[0022] Embodiment 1, referring to Figure 1 , the flow of the analysis method and system for internal excitation load and vibration transmission of the power transmission system can be calculated using, but not limited to, MATLAB software; an embodiment disclosed by the present invention, such as Figure 2As shown, a vibration transmission analysis model of a power transmission system includes 8 gears, 12 bearings, 3 splines and 2 flexible shafts, with a total of 3 meshing frequency components, namely 3 gear meshing excitation sources. A vibration acceleration sensor is installed at the bearing seat position corresponding to each gear. Therefore, there are a total of 8 vibration acceleration sensors. Each flexible shaft is divided into several rigid body units, considering the three translational and three torsional degrees of freedom of the gears and each rigid body unit; Figure 3 It is a schematic diagram of signal filtering using a comb filter. Taking the signal at the bearing seat position collected in the experiment as an example, the filtered signal spectrum obtained through the comb filter only contains the frequency components corresponding to the 3 gear meshing excitations; Figure 4 It is the result of the proportion of the vibration contribution of each meshing excitation in the bearing seat signal. The signals collected by each sensor are respectively subjected to comb filtering processing, and the vibration energy contribution evaluation index (CVE) corresponding to the 3 gear meshing excitations is calculated.

[0023] Reference Figure 1 , the method for analyzing the internal excitation load and vibration transmission of the power transmission system in this embodiment includes the following steps: S1. Establish a gear dynamic meshing stiffness model based on gear parameters and the fast influence coefficient method. The gear parameters include the mass, moment of inertia, number of teeth, tooth width, module and center hole radius of the gear. The establishment of the gear dynamic meshing stiffness model by the fast influence coefficient method includes: discretizing the contact area of the meshing tooth pair into several units, calculating the bending, axial compression, shear, Hertz contact and fillet base deformation coefficients between the discrete units based on the gear parameters and the position of the gear meshing point, and establishing an influence coefficient matrix; determining the clearance between the discrete units of the contact tooth pair, and equivalenting the gear dynamic transmission error to the elastic approach amount. Then, combining the influence coefficient matrix to establish a clearance-deformation equation set, that is, the gear dynamic meshing stiffness model, and the gear dynamic meshing stiffness can be obtained by iterative solution; S2. Obtain the spline equivalent support stiffness based on spline parameters and the gear-spline coupling model. The spline parameters include the number of teeth, module, pressure angle and tooth width. The gear-spline coupling model considers the spline fit clearance. First, determine the position where the gear and the spline make initial contact, and set the initial rotational speed. Then, determine the change amount of the spline pair clearance sequence according to the direction of the meshing force, and establish a gear-spline translational and torsional motion equation set, that is, the spline parameter and the gear-spline coupling model. The force, moment and relative displacement between the internal spline and the external spline can be obtained by numerical solution; the spline equivalent support stiffness is obtained by differentiating the relative displacement with respect to the force and moment between the internal spline and the external spline; S3. Establish a flexible shaft model based on the shaft parameters, and establish a vibration transfer analysis model of the power transmission system in combination with the gear dynamic meshing stiffness model, the equivalent support stiffness of the spline, and the equivalent support stiffness of the bearing. The shaft parameters include the mass, length, and moment of inertia of the shaft; The flexible shaft model can be established by the rigid body element method. First, divide the shaft into several rigid body elements, then calculate the equivalent support stiffness between adjacent rigid body elements based on the shaft parameters and the theory of mechanics of materials. Finally, establish the dynamic equations of each rigid body element in the translation direction based on Newton's equations, and establish the dynamic equations of each rigid body element in the torsional direction based on Euler's equations. The established equations are the flexible shaft model. The equivalent support stiffness of the bearing assumes the bearing as a spring-damper structure. The vibration transfer analysis model of the power transmission system is based on the flexible shaft model, and converts the gear dynamic meshing stiffness into dynamic meshing force and introduces it into the flexible shaft dynamic equations. The spline is equivalent to the support stiffness and support damping, and calculates the spline support force by combining the relative displacement and relative velocity between the gear and the shaft unit connected by the spline. The bearing is equivalent to the support stiffness and support damping, and calculates the bearing support force by combining the relative displacement and relative velocity between the outer ring of the bearing and the shaft unit connected by the bearing. Finally, the vibration transfer analysis model of the power transmission system is obtained; S4. Based on the vibration transfer analysis model of the power transmission system, obtain the vibration acceleration at each bearing seat position through simulation solution. The simulation solution process is based on the Runge-Kutta method. First, set the initial positions and initial angular velocities of each component of the power transmission system, then set the simulation duration and sampling frequency, and finally convert the bearing seat displacement and velocity obtained by the simulation into the acceleration signal of the bearing seat through the motion equations; S5. Define the transfer function of the comb filter based on the meshing frequency and sampling frequency of the power transmission system H , the meshing frequency of the power transmission system is calculated by the product of the gear speed and the number of teeth, and there are multiple meshing frequency components in the power transmission system. The sampling frequency is the number of sampling points per unit time. The expression of the comb filter is:

[0024] where is a constant in the interval (0,1). Decreasing the value increases the influence of the filter on other frequency signals, makes the frequency response curve steeper, and the filtering effect is better. represents the filtering order. For better filtering effect, the filtering order for different meshing frequencies should be an integer, which can be achieved by resampling the original signal; S6. Combine the vibration acceleration signals at the positions of each bearing housing obtained from the experiment and the vibration acceleration signals at the positions of each bearing housing obtained from the simulation, and respectively extract the signals of each meshing frequency component of the power transmission system from the acquired signals based on a comb filter. The vibration acceleration signals at the positions of each bearing housing in the experiment are obtained through a vibration transmission analysis test bench for the power transmission system. The parameters of the vibration transmission analysis test bench for the power transmission system are consistent with the parameters of the simulation model. The vibration acceleration signals of each bearing housing collected in the experiment contain each meshing frequency component and noise components. Use the designed comb filter to perform comb filtering on the experimental signals, and extract the signals of each frequency component from the vibration acceleration signals at the positions of each bearing housing obtained from the experiment. For the vibration acceleration signals at the positions of each bearing housing obtained from the simulation, also use the comb filter to extract the signals of each frequency component; S7. Based on the signals of each frequency component extracted by the comb filter, define the vibration energy contribution evaluation index CVE of the internal excitation, analyze the proportion of the vibration contribution of each internal excitation in the signals of each bearing housing, verify the correctness of the simulation model by comparing the simulation and experimental results, and calculate the load transfer law of the internal excitation between each transmission component through the simulation model, so as to reveal the transmission law of the internal excitation in the power transmission system. The internal excitation is the gear meshing excitation, and the vibration energy contribution evaluation index CVE is expressed as:

[0025] where the subscript i represents the i th gear meshing excitation source, represents the energy of the signal corresponding to the i th meshing frequency component, represents the number of meshing excitation sources included in the power transmission system. There are multiple meshing excitation sources in the signal of the same bearing housing measurement point. By calculating the CVE values of each meshing excitation, the vibration contribution characterization of the meshing excitation at this measurement point can be revealed. By calculating the CVE values of the bearing housing positions corresponding to all gears and plotting them in the form of a bar chart, the coupling vibration mechanism of the power transmission system can be intuitively represented. Verify the correctness of the simulation model by comparing the experimental and simulation results. Based on the simulation dynamics model, output the acting forces between each transmission component, obtain the load transfer law of the internal excitation between each transmission component, and finally reveal the vibration characterization and transmission law of the internal excitation in the entire power transmission system; According to Figure 2Taking an embodiment disclosed by the present invention as an example for calculation and description, an input torque is applied to the #1 end of the flexible shaft, a load torque of 50 Nm is applied to the #1 end of the brake, a load torque of 200 Nm is applied to the #2 end of the brake, the rotational speed of the input flexible shaft #1 is set to 1200 r / min, the initial rotational speeds of the flexible shaft #2 and all gears are set based on the gear transmission ratio, the simulation time is set to 1 s, the Runge-Kutta method is used for solving, vibration acceleration signals at 8 bearing block positions are obtained, and corresponding experiments are carried out to obtain vibration acceleration signals at 8 bearing block positions in the experiment; Figure 3 is a schematic diagram of signal filtering using a comb filter. Taking the signals at the bearing block positions collected in the experiment as an example, the of the comb filter is set to 0.15, the sampling frequency is set to 25600 Hz, the meshing frequencies of the three gears in the transmission system are 1180 Hz, 660 Hz and 1061 Hz respectively, different filtering orders are set for the three meshing frequencies respectively, and finally a signal containing only the meshing frequency after filtering is obtained. Figure 4 is the vibration contribution result of each meshing excitation in the bearing block signal. The signals collected by each sensor are respectively subjected to comb filter processing, and the vibration energy contribution evaluation index (CVE) corresponding to the three meshing excitations is calculated. It can be seen that the main vibration contribution at the positions of sensor #1 and sensor #2 comes from meshing excitation #1, at the positions of sensor #5, sensor #6, sensor #7 and sensor #8, the main vibration contribution comes from meshing excitation #3, while at the positions of sensor #3 and sensor #4, the vibration contributions of the three excitation sources cannot be ignored. From this result, the vibration mechanism of the power transmission system and the vibration transmission law of the meshing excitation can be intuitively reflected.

[0026] Embodiment 2, based on the technical concept of the above method, the present invention also provides an internal excitation load and vibration transmission analysis system for a power transmission system, including a comb filter establishment and solution module, a vibration energy contribution evaluation index establishment module and a solution module; The gear dynamic meshing stiffness establishment module is used to establish an influence coefficient matrix of the contacting tooth pair based on gear parameters and the influence coefficient method, and establish a clearance-deformation equation set in combination with the contacting tooth profile clearance vector and the elastic approach amount; The spline equivalent support stiffness calculation module is used to establish a dynamic model of the gear spline coupling system based on spline parameters and gear parameters, and obtain the acting force, acting moment and relative displacement between the internal spline and the external spline through numerical calculation, and obtain the spline equivalent support stiffness by calculating the differential of the acting force and the acting moment with respect to the displacement; The dynamic transmission system vibration transfer analysis model establishment module first establishes a flexible shaft model based on the shaft parameters and the rigid body element method. Then, it converts the gear dynamic meshing stiffness into a dynamic meshing force and applies it to the flexible shaft dynamics equations. It calculates the spline support force based on the relative displacement and relative velocity between the gear and the shaft, and calculates the bearing support force based on the relative displacement and relative velocity between the bearing outer ring and the shaft. Finally, it establishes a dynamic transmission system vibration transfer analysis model; The comb filter establishment and solution module is used to establish the transfer function of the comb filter H and obtains a signal that can be filtered by an integer-order comb filter through signal resampling. Then, it performs comb filtering on the signals at the bearing housing positions obtained from experiments and simulations respectively, and extracts the signals of each meshing frequency component; The vibration energy contribution evaluation index establishment and solution module is used to establish the vibration energy contribution evaluation index CVE, solve the CVE values of the signals at the bearing housing positions corresponding to all gears in the dynamic transmission system, draw a bar chart of the vibration contributions of each measurement point in the dynamic transmission system, and output the acting forces between each transmission component.

[0027] It also includes a gear dynamic meshing stiffness establishment module, a spline equivalent support stiffness calculation module, and a dynamic transmission system vibration transfer analysis model establishment module; The gear dynamic meshing stiffness establishment module is used to establish an influence coefficient matrix of the contacting tooth pair based on the gear parameters and the influence coefficient method, and establish a clearance-deformation equation set in combination with the contacting tooth profile clearance vector and the elastic approach amount; The spline equivalent support stiffness calculation module is used to establish a dynamic model of the gear spline coupling system based on the spline parameters and the gear parameters, obtain the acting force, acting torque, and relative displacement between the internal spline and the external spline through numerical calculation, and calculate the spline equivalent support stiffness by differentiating the acting force and acting torque with respect to the displacement; The dynamic transmission system vibration transfer analysis model establishment module first establishes a flexible shaft model based on the shaft parameters and the rigid body element method. Then, it converts the gear dynamic meshing stiffness into a dynamic meshing force and applies it to the flexible shaft dynamics equations. It calculates the spline support force based on the relative displacement and relative velocity between the gear and the shaft, and calculates the bearing support force based on the relative displacement and relative velocity between the bearing outer ring and the shaft. Finally, it establishes a dynamic transmission system vibration transfer analysis model.

[0028] The above content is only to illustrate the technical idea of the present invention and cannot be used to limit the protection scope of the present invention. Any modification made on the basis of the technical solution according to the technical idea proposed by the present invention falls within the protection scope of the claims of the present invention.

Claims

1. Analysis method for internal excitation load and vibration transmission of a power transmission system, characterized in that It includes the following steps: Define the transfer function of the comb filter based on the meshing frequency and sampling frequency of the powertrain H ; Obtain the vibration acceleration signals at the positions of each bearing housing in experiments and simulations, and respectively extract the signals of each meshing frequency component of the power transmission system from the acquired signals based on a comb filter; Based on the signals extracted by the comb filter, define the vibration energy contribution evaluation index CVE of the internal excitation, analyze the proportion of the vibration contribution of each internal excitation in the signals of each bearing housing, verify the correctness of the simulation model by comparing the simulation and experimental results, and calculate the load transfer law of the internal excitation between each transmission component through the simulation model, so as to reveal the transfer law of the internal excitation in the power transmission system.

2. The method for analyzing the internal excitation load and vibration transmission of the power transmission system according to claim 1, characterized in that Define the transfer function of the comb filter based on the meshing frequency and sampling frequency of the powertrain H When the meshing frequency of the powertrain is calculated by the product of the gear speed and the number of teeth, and there are multiple meshing frequency components in the powertrain, the sampling frequency is the number of sampling points per unit time, and the expression of the comb filter is as follows: Among them, is a constant on the interval (0, 1). Decreasing value, the influence of the filter on other frequency signals increases, the frequency response curve becomes steeper, and the filtering effect is better. represents the filtering order. The filtering order for different meshing frequencies should be an integer and is achieved by resampling the original signal.

3. The method for analyzing the internal excitation load and vibration transmission of the power transmission system according to claim 1, characterized in that, The internal excitation mentioned above is the gear meshing excitation, and the vibration energy contribution evaluation index CVE is expressed as: Among them, the subscript i represents the i th gear meshing excitation source, represents the energy of the signal corresponding to the i th meshing frequency component, represents the number of meshing excitation sources included in the power transmission system. There are multiple meshing excitation sources in the signal of the same bearing seat measurement point. By calculating the CVE values of each meshing excitation, the vibration contribution characterization of the meshing excitation at this measurement point is revealed. By calculating the CVE values of the bearing seat positions corresponding to all gears and plotting them in the form of a bar chart, the coupling vibration mechanism of the power transmission system is visually represented. By comparing the experimental and simulation results, the correctness of the simulation model is verified. Based on the simulation dynamics model, the forces between each transmission component are output, the load transfer law of the internal source excitation between each transmission component is obtained, and finally the vibration characterization and transfer law of the internal source excitation in the entire power transmission system are revealed.

4. The method for analyzing the load and vibration transfer of the internal excitation of the power transmission system according to claim 1, wherein Obtaining the vibration acceleration signals at the positions of each bearing housing in the simulation includes the following steps: Establish a gear dynamic meshing stiffness model based on gear parameters and the fast influence coefficient method; Obtain the equivalent support stiffness of the spline based on spline parameters and the gear-spline coupling model; Establish a flexible shaft model based on shaft parameters, and establish a vibration transfer analysis model of the power transmission system in combination with the gear dynamic meshing stiffness model, the equivalent support stiffness of the spline, and the equivalent support stiffness of the bearing; Based on the vibration transfer analysis model of the power transmission system, obtain the vibration acceleration at the positions of each bearing housing through simulation solution.

5. The method for analyzing the internal excitation load and vibration transmission of a power transmission system according to claim 4, wherein The gear parameters mentioned above include the mass, moment of inertia, number of teeth, tooth width, module, and center hole radius of the gear. The fast influence coefficient method discretizes the contact area of the meshing tooth pair into several units, calculates the bending, axial compression, shear, Hertz contact, and fillet base deformation coefficients between each discrete unit based on the gear parameters and the position of the gear meshing point, and establishes an influence coefficient matrix. The gear dynamic meshing stiffness model first determines the clearance between the discrete units of the contacting tooth pair, and equivalent the gear dynamic transmission error to the elastic approach amount, and then combines the influence coefficient matrix to establish a clearance-deformation equation set, and obtains the gear dynamic meshing stiffness through iterative solution.

6. The method for analyzing the internal excitation load and vibration transmission of a power transmission system according to claim 4, wherein The spline parameters mentioned above include the number of teeth, module, pressure angle, and tooth width, and the gear-spline coupling model considers the spline fit clearance; The establishment of the spline parameters and the gear-spline coupling model includes: first determining the position where the gear and the spline make initial contact, and setting the initial rotational speed, and then determining the change amount of the spline pair clearance sequence according to the direction of the meshing force, and establishing a gear-spline translation and torsion motion equation set, that is, the spline parameters and the gear-spline coupling model; The equivalent support stiffness of the spline is obtained by differentiating the relative displacement with respect to the acting force and the acting moment between the internal spline and the external spline.

7. The method for analyzing the internal excitation load and vibration transmission of a power transmission system according to claim 4, wherein The shaft parameters mentioned above include the mass, length, and moment of inertia of the shaft. The flexible shaft model is established by the rigid body element method, including: dividing the shaft into several rigid body elements, calculating the equivalent support stiffness between adjacent rigid body elements based on the shaft parameters and the theory of mechanics of materials, establishing the dynamic equations of each rigid body element in the translation direction based on Newton's equation, and establishing the dynamic equations of each rigid body element in the torsion direction based on Euler's equation. The established equation set is the flexible shaft model.

8. The method for analyzing the internal excitation load and vibration transmission of a power transmission system according to claim 7, wherein The vibration transfer analysis model of the power transmission system is established by combining the dynamic meshing stiffness model of gears, the equivalent support stiffness of splines, and the equivalent support stiffness of bearings, including: the equivalent support stiffness of bearings assumes the bearings as a spring-damper structure. The vibration transfer analysis model of the power transmission system is based on the flexible shaft model. The dynamic meshing stiffness of gears is converted into dynamic meshing forces and introduced into the flexible shaft dynamics equations. The splines are equivalent to support stiffness and support damping, and the spline support forces are calculated by combining the relative displacements and relative velocities between the gears and shaft units connected by the splines. The bearings are equivalent to support stiffness and support damping, and the bearing support forces are calculated by combining the relative displacements and relative velocities between the outer rings of the bearings and the shaft units connected by the bearings, thus obtaining the vibration transfer analysis model of the power transmission system.

9. The method for analyzing the internal excitation load and vibration transmission of the power transmission system according to claim 1, wherein In the described experiment, the parameters of the vibration transfer analysis test bench of the power transmission system are consistent with those of the simulation model. The vibration acceleration signals of each bearing block collected in the experiment contain various meshing frequency components and noise components. The comb filter is used to perform comb filtering on the experimental signals, and finally, the signals of each frequency component are extracted from the experimental signals. For the vibration acceleration signals of each bearing block position obtained by simulation, the comb filter is also used to extract the signals of each frequency component.

10. A system for analyzing the internal excitation load and vibration transmission of a power transmission system, characterized in that, Comb filter establishment and solution module, vibration energy contribution evaluation index establishment module, and solution module; The comb filter establishment and solution module is used to establish the transfer function of the comb filter H , and obtain signals that can be filtered by an integer-order comb filter by resampling the signals. Then, the signals of the bearing housing positions obtained from experiments and simulations are respectively subjected to comb filtering to extract the signals of each meshing frequency component; The vibration energy contribution evaluation index establishment module and the solution module are used to establish the vibration energy contribution evaluation index CVE, solve the CVE values of the signals at the bearing block positions corresponding to all gears in the power transmission system, draw the bar chart of the vibration contributions of each measuring point in the power transmission system, and output the acting forces between each transmission component.

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