Passenger car transmission shaft vibration absorber matching method

Abstract

The invention belongs to the technical field of passenger car transmission shaft design, and particularly relates to a passenger car transmission shaft vibration absorber matching method. In a transmission shaft three-dimensional model design stage, the number of transmission shaft sections and a transmission shaft elastomer modal matching principle are defined, a transmission shaft finite element mesh model is established according to a three-dimensional model of a transmission shaft assembly, and first-order bending modal frequencies and first-order bending modal shapes of the three shaft sections of the transmission shaft are obtained respectively; for the transmission shaft section of which the first-order bending mode frequency does not meet the matching principle, the transmission shaft section has the risk of being excited at a high speed in the vehicle, and the transmission shaft section is determined as the shaft section needing to be matched with the built-in vibration absorber; frequency response curves of the shaft section needing to be matched with the built-in vibration absorber under the two conditions that the vibration absorber is installed and the vibration absorber is not installed are calculated; according to the frequency response curve, for the vibration absorbers which do not meet the following conditions, the quality and rigidity of the vibration absorbers are suggested to be modified until the following conditions are met; the method can effectively solve the problem of order vibration noise of the inner transmission shaft under a fixed vehicle speed caused by unreasonable design of the transmission shaft, and is simple and effective.

Description

Technical Field

[0001] The invention belongs to the technical field of passenger car transmission shaft design, and in particular relates to a passenger car transmission shaft vibration absorber matching method. Background Art

[0002] In the high-end passenger car market segment, four-wheel drive and front-rear-wheel drive passenger cars are still the core areas of fierce competition among major OEMs. At present, this type of passenger car is mainly engine-driven and has front and rear drive shafts. Since the drive shaft is the "artery" for the front powertrain to drive the rear wheels, if its structural design is unreasonable, it will lead to a series of performance problems, which not only include fatigue durability but also NVH performance. The common NVH problem is caused by the unreasonable modal design of the drive shaft, which resonates when the vehicle is driving at medium and high speeds, resulting in low-frequency, single-frequency and large-amplitude noise in the car, and the driver and passengers will have a serious ear-squeezing roar. The cause and mechanism of the roar are relatively complex. The main solutions in the current literature are matching the dual-mass flywheel of the transmission system, adding a torsional vibration damper, optimizing the intake and exhaust system, optimizing the suspension, strengthening the body structure, or adding a dynamic vibration absorber to the chassis system. There are also methods to optimize the second-order roar of the engine by matching a dynamic vibration absorber on the rear main reducer, or to optimize the roar in the car caused by the rear main reducer by using a dynamic vibration absorber and to optimize the roar in the car by adding a dynamic vibration absorber on the drive half shaft. There are three necessary conditions for the roar in the car: excitation, closed space, and coupling of thin-walled structure vibration with the cavity sound mode in the car. In order to solve the roar, it is necessary to first find the excitation source and transmission path of the roar, and then propose corresponding solutions. In addition to the above methods, due to the long wheelbase of the vehicle, the length of the drive shaft is also lengthened at any time. Due to its structure and body layout, only a two-stage drive shaft can be used, resulting in a long single-stage drive shaft. The first-order mode is excited at medium and high speeds of the vehicle, which has a huge impact on fatigue durability and NVH performance. The use of built-in vibration absorbers is not only simple and effective in solving the problem, but also intersects with changing the body or increasing the number of drive shaft sections, and its cost is greatly reduced.

[0003] As competition in the high-end passenger car market segment becomes increasingly fierce, OEMs need to greatly shorten product development cycles and costs, so virtual simulation technology and its maturity are becoming increasingly important in guiding the product development process. For four-wheel drive and front-rear drive passenger cars with drive shafts, the forward development of various performances of the drive shaft in the early stage has also become an important part of the vehicle development process. Drive shaft modal control is the basic content of drive shaft forward development and is also an indispensable indicator. However, for some passenger car products, due to various conditional limits, the drive shaft modal cannot achieve the development goal at all, so that the first-order mode is excited at medium and high speeds of the vehicle, which has a huge impact on fatigue durability and NVH performance. If the NVH risk caused by unreasonable drive shaft modal design is avoided in the early stage of product development, it will greatly reduce the recall and complaints caused by drive shaft NVH performance in passenger car products entering the market.

[0004] However, there are few solutions in the existing public technologies for matching the drive shaft of the whole vehicle with built-in vibration absorbers. Similar problems are basically solved by modifying the body structure or the torsional vibration solution of the transmission system, but this solution is costly and takes a long time. Summary of the invention

[0005] In order to overcome the above problems, the present invention provides a method for matching a transmission shaft vibration absorber for a passenger car; the present invention can effectively solve the problem of order vibration noise of the transmission shaft at a fixed vehicle speed caused by unreasonable transmission shaft design, which is simple and effective.

[0006] A passenger car transmission shaft vibration absorber matching method, comprising the following contents:

[0007] Step 1: In the design stage of the three-dimensional model of the transmission shaft, the number of transmission shaft segments and the modal matching principle of the transmission shaft elastic body are defined. The principle is:

[0008]

[0009] Where: f 1 is the minimum limit of the bending modal frequency of any shaft section of the transmission shaft; K is the safety factor; V max is the maximum speed; i g is the rear main reduction ratio; P order is the order defined according to the drive shaft structure. For a flexible disc drive shaft, this value is 1, for a cross-type drive shaft, this value is 2, for a constant velocity joint drive shaft, this value is 3 or 4, pi is the circumference of a circle, and r is the rolling radius of the tire;

[0010] Step 2, obtaining a three-dimensional model of the transmission shaft assembly;

[0011] Step 3: Establish a finite element mesh model of the transmission shaft according to the three-dimensional model of the transmission shaft assembly, and obtain the first-order bending mode frequency and the first-order bending mode vibration shape of the three shaft segments of the transmission shaft. For the transmission shaft segments whose first-order bending mode frequency does not meet the corresponding shaft segment matching principle in step 1, there is a risk of being excited at high speeds in the vehicle, and they are determined as shaft segments that need to be matched with built-in vibration absorbers;

[0012] Step 4, calculating the frequency response curves of the shaft section that needs to be matched with the built-in vibration absorber in two cases: with the vibration absorber installed and without the vibration absorber installed;

[0013] Step 5: According to the frequency response curve, for the vibration absorber that does not meet the following conditions, it is recommended to modify the mass and stiffness of the vibration absorber until the following conditions are met; the conditions are:

[0014] The peak value of the frequency response curve of the shaft section equipped with the vibration absorber is not greater than the peak value of the frequency response curve of the shaft section without the vibration absorber installed.

[0015] In the step 1, K is 1.2-1.4.

[0016] In step 3, the first-order bending modal frequencies and first-order bending modal vibration shapes of the three shaft sections of the transmission shaft are obtained according to the following process:

[0017] Step 1, preparing three-dimensional data of the transmission shaft assembly including the transmission shaft tube, universal joint, connecting flange and solid shaft;

[0018] Step 2, establishing a finite element model of the transmission shaft assembly through the pre-processing software HyperMesh;

[0019] Step 3, constrain the connection relationship of each component of the finite element model according to the actual state in the pre-processing software HyperMesh;

[0020] Step 4: Select the mass option in the EIGRL tab of the pre-processing software HyperMesh, and set the modal calculation range to 1-1000 Hz;

[0021] Step 5, set the calculation solver to nastran SOL103;

[0022] Step 6: After the settings are completed, output the displacement information of all nodes of the model and specify the calculation results as .op2 file;

[0023] Step 7, submit the .op2 file to MSC-Nastran software for calculation, and output the *.op2 file after the calculation is completed;

[0024] Step 8: Use Hyperview / Hyperworks post-processing software to view the *.op2 file of the calculation results and obtain the first-order bending mode frequency and the first-order bending mode vibration shape.

[0025] The finite element mesh model established in step 3 adopts a tetrahedral ten-node mesh with an average mesh size of 3 mm, and the shaft tube adopts a quadrilateral two-dimensional mesh.

[0026] In step 4, the mass of the vibration absorber installed on the shaft segment that needs to match the built-in vibration absorber is 2% to 5% of the total weight of the transmission shaft.

[0027] Beneficial effects of the present invention:

[0028] The present invention can effectively solve the problem of order vibration noise of the drive shaft at a fixed vehicle speed caused by unreasonable drive shaft design. It is simple and effective, and does not require modification of the vehicle body structure or the transmission system torsional vibration solution to solve the drive shaft NVH problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without creative work.

[0030] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0032] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0033] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0034] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0035] Example 1

[0036] A passenger car transmission shaft vibration absorber matching method, comprising the following contents:

[0037] Step 1: After the start-up phase of the drive shaft design project, in the three-dimensional model design phase of the drive shaft, define the number of drive shaft segments and the modal matching principle of the drive shaft elastic body. The principle is:

[0038]

[0039] Where: f 1 is the minimum limit of the bending modal frequency of any shaft section of the transmission shaft; K is the safety factor formulated according to actual conditions, generally 1.2-1.4; V max is the maximum speed; i g is the rear main reduction ratio; P order is the order defined according to the structure of the transmission shaft. For a flexible disc transmission shaft, this value is 1, for a cross-type transmission shaft, this value is 2, for a constant velocity joint transmission shaft, this value is 3 or 4 according to the structure, pi is the circumference of a circle, and r is the rolling radius of the tire;

[0040] Step 2: Obtain the 3D model of the drive shaft assembly through the drive shaft product design department and the vehicle general layout department. The model should be detailed and complete, including the material grade and weight of each component.

[0041] Step 1 uses the formula to calculate the minimum limit requirements, while the finite element model calculation is to calculate the actual first-order bending mode requirements of the structure;

[0042] Step 3, establish a finite element mesh model of the transmission shaft according to the three-dimensional model of the transmission shaft assembly. It is recommended to use a tetrahedral ten-node mesh with an average mesh size of 3mm for the solid structure, and a quadrilateral two-dimensional mesh for the shaft tube, and obtain the first-order bending mode frequency and the first-order bending mode vibration type of the three shaft sections of the transmission shaft respectively. For the transmission shaft section whose first-order bending mode frequency does not meet the corresponding shaft section matching principle in step 1, there is a risk of being excited at high speed in the vehicle, and it is determined as a shaft section that needs to be matched with a built-in vibration absorber; (the transmission shaft generally has a maximum of three sections. If the lower bending mode appears in the front section, the vibration absorber is matched in the front section; if it appears in the middle, the vibration absorber is matched in the middle; if it appears in the rear section, the vibration absorber is matched in the rear section);

[0043] Step 4: Calculate the frequency response curves of the shaft section that needs to match the built-in vibration absorber in the two cases of installing the vibration absorber and not installing the vibration absorber.

[0044] Step 5, obtain a schematic diagram of the frequency response calculation results with and without a vibration absorber; according to the frequency response curve, for the vibration absorber that does not meet the following conditions, it is recommended to modify the mass and stiffness of the vibration absorber until the following conditions are met; the conditions are:

[0045] The peak value of the frequency response curve of the shaft section equipped with the vibration absorber is not greater than the peak value of the frequency response curve of the shaft section without the vibration absorber installed.

[0046] In step 3, the first-order bending modal frequencies and first-order bending modal vibration shapes of the three shaft sections of the transmission shaft are obtained according to the following process:

[0047] Step 1: Prepare the 3D data of the transmission shaft assembly including the transmission shaft tube, universal joint, connecting flange and solid shaft, and also include the name and material grade of each component;

[0048] Step 2, establishing a finite element model of the transmission shaft assembly through the pre-processing software HyperMesh;

[0049] Step 3: Set the calculation boundary conditions and constrain the connection relationship of each component of the finite element model according to the actual state in the pre-processing software HyperMesh;

[0050] Step 4, set the calculation method and calculation range: use the Lanczos eigenvalue solution method, select the mass option of the EIGRL tab in the pre-processing software HyperMesh, and set the modal calculation range to 1-1000Hz;

[0051] Step 5, set the calculation solver to nastran SOL103;

[0052] Step 6: After the settings are completed, output the displacement information of all nodes of the model and specify the calculation results as .op2 file;

[0053] Step 7, submit the .op2 file to MSC-Nastran software for calculation, and output the *.op2 file after the calculation is completed;

[0054] Step 8: Use Hyperview / Hyperworks post-processing software to view the *.op2 file of the calculation results and obtain the first-order bending mode frequency and the first-order bending mode vibration shape.

[0055] The frequency response curve acquisition process in step 4 is as follows:

[0056] The frequency response curve is calculated based on the finite element mesh model of the transmission shaft established in step 3. The mass of the vibration absorber is given at 2% to 5% of the total weight of the transmission shaft at the middle position of the shaft section where the built-in vibration absorber is required. The vibration absorber stiffness k is calculated as follows:

[0057]

[0058] Where: m is the mass of the vibration absorber, M is the mass of the transmission shaft, and μ is the mass ratio of the dynamic vibration absorber to the main vibration system;

[0059] The vibration absorber uses mass point equivalent in the finite element model, the middle of the shaft tube is connected with a rigid unit, the center point of the rigid unit and the equivalent mass point of the vibration absorber are connected with a spring, the spring stiffness uses the vibration absorber stiffness k, a force of 1N is loaded at the rigid point end, the frequency calculation range is set to 0~1000Hz (generally the vibration absorber frequency is <200Hz), and the frequency response curve of this point is obtained as the frequency response curve of the shaft section.

[0060] For the finite element mesh model established in step 3, it is recommended that a tetrahedral ten-node mesh with an average mesh size of 3 mm be used for the solid structure, and a quadrilateral two-dimensional mesh be used for the shaft tube.

[0061] In step 4, the mass of the vibration absorber installed on the shaft segment that needs to match the built-in vibration absorber is 2% to 5% of the total weight of the transmission shaft.

[0062] Example 2

[0063] A passenger car transmission shaft vibration absorber matching method, comprising the following contents:

[0064] Step 1: After the start-up phase of the drive shaft design project, in the three-dimensional model design phase of the drive shaft, define the number of drive shaft segments and the modal matching principle of the drive shaft elastic body. The principle is:

[0065]

[0066] Where: f 1 is the minimum limit of the bending modal frequency of any shaft section of the transmission shaft; K is the safety factor formulated according to actual conditions, generally 1.2-1.4; V max is the maximum speed; i g is the rear main reduction ratio; P order is the order defined according to the structure of the transmission shaft. For a flexible disc transmission shaft, this value is 1; for a cross-type transmission shaft, this value is 2; for a constant velocity section transmission shaft, this value is 3 or 4 according to the structure; pi is the circumference of a circle, and r is the rolling radius of the tire;

[0067] Step 2: Obtain the 3D model of the drive shaft assembly through the drive shaft product design department and the vehicle general layout department. The model should be detailed and complete, including the material grade and weight of each component.

[0068] Step 1 uses the formula to calculate the minimum limit requirements, while the finite element model calculation is to calculate the actual first-order bending mode requirements of the structure;

[0069] Step 3, establish a finite element mesh model of the transmission shaft according to the three-dimensional model of the transmission shaft assembly. It is recommended to use a tetrahedral ten-node mesh with an average mesh size of 3mm for the solid structure, and a quadrilateral two-dimensional mesh for the shaft tube. The first-order bending mode frequency and the first-order bending mode vibration type of the three shaft sections of the transmission shaft are calculated respectively. For the transmission shaft section whose first-order bending mode frequency does not meet the corresponding shaft section matching principle in step 1, there is a risk of being excited at high speed in the vehicle, and it is determined as a shaft section that needs to be matched with a built-in vibration absorber; (the transmission shaft generally has a maximum of three sections. If the lower bending mode appears in the front section, the vibration absorber is matched in the front section; if it appears in the middle, the vibration absorber is matched in the middle; if it appears in the rear section, the vibration absorber is matched in the rear section);

[0070] Step 4: The matching principle of the built-in vibration absorber is:

[0071] The following formulas are used to design the elastic stiffness and damping of the vibration absorber:

[0072] μ=m / M (1)

[0073] μ: mass ratio of dynamic vibration absorber to main vibration system;

[0074] m: The mass of the vibration absorber. The recommended mass of the vibration absorber is 2% to 5% of the total weight of the transmission shaft; m = μM;

[0075] M: transmission shaft mass;

[0076] The elastic stiffness k of the dynamic vibration absorber is:

[0077] Stiffness deviation ±15%

[0078] Optimal damping ratio ζ of dynamic vibration absorber 最优 for:

[0079] Step 5: Use the frequency response calculation method to calculate the frequency response curve of the shaft section that needs to match the built-in vibration absorber in the two cases of installing the vibration absorber and not installing the vibration absorber. The frequency response curve calculation process is as follows:

[0080] The frequency response curve is calculated based on the finite element mesh model of the transmission shaft established in step 3. The mass of the vibration absorber is given at 2% to 5% of the total weight of the transmission shaft at the middle position of the shaft section that needs to match the built-in vibration absorber; the stiffness of the vibration absorber is given according to formula (2); the vibration absorber adopts mass point equivalent in the finite element model, the middle of the shaft tube is connected with a rigid unit, and the center point of the rigid unit and the equivalent mass point of the vibration absorber are connected with a spring. The spring stiffness adopts the stiffness calculated by formula (2), and a force of 1N is loaded at the rigid point end. The frequency calculation range is set to 0 to 1000Hz (generally the frequency of the vibration absorber is less than 200Hz). The frequency response curve of this point is calculated as the frequency response curve of the shaft section;

[0081] Step 6, obtain a schematic diagram of the frequency response calculation results with and without a vibration absorber; for vibration absorbers that do not meet the following conditions, it is recommended to modify the mass and stiffness of the vibration absorber until the following conditions are met; the conditions are:

[0082] The peak value of the frequency response curve of the shaft section equipped with the vibration absorber is not greater than the peak value of the frequency response curve of the shaft section without the vibration absorber installed.

[0083] Step 7, match the built-in vibration absorber of the transmission shaft according to the calculation results, that is, match the mass, damping and stiffness of the vibration absorber, make a physical object to test the frequency response of the transmission shaft, and obtain the physical object and frequency response test results of the transmission shaft with vibration absorber. In order to verify whether the calculation results are accurate and reliable, the three-axis acceleration sensor is arranged at the vibration absorber position during the test to test the vertical frequency response of the transmission shaft. If the frequency error is within 10%, it is considered that the vibration absorber is matched reasonably.

[0084] Step 8: To verify the effect of the vibration absorber, the NVH performance of the vehicle with and without the vibration absorber drive shaft is verified based on the test results.

[0085] In the step 2, a finite element model of the transmission shaft assembly is established, and each component is assembled according to the actual situation. The finite element mesh modeling requirements of each part are as follows: the flange requires the finite element mesh to use tetrahedral second-order units; the average unit size is recommended to be 3mm; the two-dimensional unit requirements are: more than 95% of the unit aspect ratio is less than 5, more than 95% of the unit warping angle is less than 10 degrees, more than 95% of the unit skew angle is greater than 60 degrees, more than 95% of the unit minimum angle is greater than 40 degrees, and more than 95% of the unit maximum angle is less than 120 degrees. The shaft tube requires the use of quadrilateral first-order shell units; the average unit size is recommended to be 3mm; unit requirements: the total number of triangular units is less than 5% of the total number of shaft tube units, more than 95% of the unit aspect ratio is less than 5, more than 95% of the unit warping angle is less than 10 degrees, more than 95% of the unit skew angle is greater than 60 degrees, more than 95% of the unit minimum angle is greater than 40 degrees, and more than 95% of the unit maximum angle is less than 120 degrees. The shell unit is connected with the corresponding solid unit. The constant velocity universal joint is simplified by spring units. The dust cover and lubricating oil are simplified in the model. Check whether the assembly between the components is correct; whether the unit properties, material properties, and constraint conditions are loaded correctly; check whether the mass of each component and the total mass of the model are consistent with the actual model. Extract the modal vibration shape and modal frequency within 1Hz~1000Hz.

[0086] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the protection scope of the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention. These simple variations all belong to the protection scope of the present invention.

[0087] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0088] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A passenger car transmission shaft vibration absorber matching method, characterized in that: It includes the following: Step 1: In the design stage of the three-dimensional model of the transmission shaft, the number of transmission shaft segments and the modal matching principle of the transmission shaft elastic body are defined. The principle is: Where: f1 is the minimum limit of the bending modal frequency of any shaft section of the transmission shaft; K is the safety factor; V max is the maximum speed; i g is the rear main reduction ratio; P order is the order defined according to the drive shaft structure. For a flexible disc drive shaft, this value is 1, for a cross-type drive shaft, this value is 2, for a constant velocity joint drive shaft, this value is 3 or 4, pi is the circumference of a circle, and r is the rolling radius of the tire; Step 2, obtaining a three-dimensional model of the transmission shaft assembly; Step 3: Establish a finite element mesh model of the transmission shaft according to the three-dimensional model of the transmission shaft assembly, and obtain the first-order bending mode frequency and the first-order bending mode vibration shape of the three shaft segments of the transmission shaft respectively. For the transmission shaft segments whose first-order bending mode frequency does not meet the corresponding shaft segment matching principle in step 1, there is a risk of being excited at high speeds in the vehicle, and they are determined as shaft segments that need to be matched with built-in vibration absorbers; Step 4: Calculate the frequency response curves of the shaft section that needs to match the built-in vibration absorber in the two cases of installing the vibration absorber and not installing the vibration absorber. Step 5: According to the frequency response curve, for the vibration absorber that does not meet the following conditions, it is recommended to modify the mass and stiffness of the vibration absorber until the following conditions are met; the conditions are: The peak value of the frequency response curve of the shaft section equipped with the vibration absorber is not greater than the peak value of the frequency response curve of the shaft section without the vibration absorber installed.

2. A passenger car transmission shaft vibration absorber matching method according to claim 1, characterized in that: In the step 1, K is 1.2-1.

4.

3. A passenger car transmission shaft vibration absorber matching method according to claim 1, characterized in that: In step 3, the first-order bending modal frequencies and first-order bending modal vibration shapes of the three shaft sections of the transmission shaft are obtained according to the following process: Step 1, preparing three-dimensional data of the transmission shaft assembly including the transmission shaft tube, universal joint, connecting flange and solid shaft; Step 2, establishing a finite element model of the transmission shaft assembly through the pre-processing software HyperMesh; Step 3, constrain the connection relationship of each component of the finite element model according to the actual state in the pre-processing software HyperMesh; Step 4: Select the mass option in the EIGRL tab of the pre-processing software HyperMesh, and set the modal calculation range to 1-1000 Hz; Step 5, set the calculation solver to nastran SOL103; Step 6: After the settings are completed, output the displacement information of all nodes of the model and specify the calculation results as .op2 file; Step 7, submit the .op2 file to MSC-Nastran software for calculation, and output the *.op2 file after the calculation is completed; Step 8: Use Hyperview / Hyperworks post-processing software to view the *.op2 file of the calculation results and obtain the first-order bending mode frequency and the first-order bending mode vibration shape.

4. A passenger car transmission shaft vibration absorber matching method according to claim 1, characterized in that: The finite element mesh model established in step 3 adopts a tetrahedral ten-node mesh with an average mesh size of 3 mm, and the shaft tube adopts a quadrilateral two-dimensional mesh.

5. The method for matching a transmission shaft vibration absorber of a passenger vehicle according to claim 1, characterized in that: In step 4, the mass of the vibration absorber installed on the shaft segment that needs to match the built-in vibration absorber is 2% to 5% of the total weight of the transmission shaft.

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