Hub bearing rigidity calculation method and device and storage medium

Abstract

The invention discloses a hub bearing rigidity calculation method and device and a storage medium, and belongs to the technical field of bearing rigidity calculation, the hub bearing rigidity calculation method comprises the following steps: fitting a Lundberg logarithmic profile by using three sections of arcs to obtain an arc fitting type roller profile; establishing a static balance equation of the double-row tapered roller bearing according to the arc fitting type roller contour; based on the static balance equation of the double-row tapered roller bearing, obtaining the relation between the displacement and the load of the double-row tapered roller bearing under the action of the radial load, the axial load and the torque considering the pre-tightening force by adopting a slicing method; solving the relation between the displacement and the load of the double-row tapered roller bearing through an implicit function differential method to obtain axial and radial stiffness models of the bearing; and inputting the basic parameters of the bearing into the axial and radial rigidity models of the bearing to calculate the rigidity of the bearing. The influence of the bearing internal convexity is fully considered, and the bearing rigidity calculation accuracy can be improved.

Description

Technical Field

[0001] The invention relates to a method, a device and a storage medium for calculating the stiffness of a hub bearing, and belongs to the technical field of bearing stiffness calculation. Background Art

[0002] As a key component connecting the vehicle wheel and the suspension system, the wheel hub bearing bears huge radial and axial loads during the driving process of the vehicle. Its performance directly affects the safety, stability and comfort of the vehicle. Therefore, accurately evaluating the stiffness of the wheel hub bearing is crucial to ensure the overall performance of the vehicle. At present, most wheel hub bearing stiffness parameters are obtained through experimental methods, which are often time-consuming and costly, and are limited by experimental conditions, making it difficult to obtain accurate data. For finite element analysis, due to the complex model establishment and variable parameters, the analysis process is time-consuming, and there are certain limitations in the simulation of nonlinear material properties. The calculation method based on the formula model has a large error when facing wheel hub bearings with new materials or complex structures, but the calculation is simple and convenient, and can provide technical reference to a certain extent. However, most existing wheel hub bearing stiffness calculation methods do not fully consider the influence of the internal convexity of the bearing, and the convexity is one of the important factors affecting the stiffness and contact stress distribution of the wheel hub bearing. Failure to consider the convexity will reduce the calculation accuracy of the bearing stiffness. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a method, device and storage medium for calculating the stiffness of a hub bearing, which fully considers the influence of the internal convexity of the bearing and can improve the calculation accuracy of the bearing stiffness.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] In a first aspect, the present invention provides a method for calculating the stiffness of a hub bearing, comprising the following steps:

[0006] The Lundberg logarithmic profile is fitted with three arc segments to obtain the arc fitting roller profile.

[0007] The static equilibrium equation of double-row tapered roller bearing is established based on the arc fitting roller profile;

[0008] Based on the static equilibrium equation of double-row tapered roller bearings, the slice method is used to obtain the relationship between the displacement and load of double-row tapered roller bearings under the action of radial load, axial load and torque considering the preload.

[0009] The relationship between displacement and load of double-row tapered roller bearing is solved by implicit function differential method to obtain the axial and radial stiffness model of the bearing.

[0010] The basic bearing parameters are input into the bearing axial and radial stiffness models to calculate the bearing stiffness.

[0011] The method of fitting the Lundberg logarithmic profile roller using three arc segments to obtain the arc fitting roller profile includes:

[0012] The curve function of the Lundberg logarithmic roller surface profile is:

[0013] (1)

[0014] Where x is the position along the roller generatrix, y1 is the training value, is the Poisson's ratio of the material, E is the elastic modulus of the roller, Q is the maximum force of the roller during roller modification design, is the effective contact length of the roller;

[0015] The curve function of the three arc fitting curve contour is:

[0016] (2)

[0017] Where y2 is the training value after fitting, 2c is the distance between the intersection points of the two arc segments, R1 is the radius of the middle arc segment, and R2 is the radius of the arc segments on both sides.

[0018] The static balance equation of the double-row tapered roller bearing established based on the arc fitting roller profile includes:

[0019] Taking the contact between the inner ring and the rolling element as the analysis object, the static equilibrium equation is:

[0020] (3)

[0021] Considering the inner ring and roller as a whole, the first row of bearings is analyzed. Under the action of external force, the axial displacement between the inner ring and the outer ring of the bearing is , radial displacement and normal displacement have:

[0022] (4)

[0023] in, Respectively represent the contact force between the rolling element and the outer raceway, inner raceway and flange, Respectively represent the contact angles between the rolling element and the outer raceway, inner raceway and rib;

[0024] No. The normal displacement between the outer rings of the bearings at each roller is:

[0025] (5)

[0026] In the formula For the Roller azimuth,

[0027] (6)

[0028] Wherein, Z is the number of rollers in a single-row bearing;

[0029] If an axial preload is applied, the axial predeformation for:

[0030] (7)

[0031] (8)

[0032] In the formula is the roller finite contact length, is the average roller diameter;

[0033] Assume the center distance between the two rows of bearings is d c , the bearing center pitch diameter is d m , at this time, the total axial displacement and radial displacement are:

[0034] (9)

[0035] (10)

[0036] Where θ is the angle between the inner and outer rings under the action of external load.

[0037] The relationship between the displacement and load of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload force is established by using the slice method based on the static balance equation of the double-row tapered roller bearing, including:

[0038] When analyzing the deformation of a tapered roller with convexity, the slicing method is used. The roller repair amount is equivalent to the negative normal displacement of the roller. The roller contacts the raceway only after the repair amount is offset at the slicing point. Roller, The normal displacement of the slice position for:

[0039] (11)

[0040] (12) (13)

[0041] So the The total contact force of the rollers is:

[0042] (14)

[0043] Where For the The number of slices on which each roller is loaded, n is the number of slices on each roller;

[0044] The above obtained The normal contact force of each roller is decomposed into axial force and radial force, and then the axial force of the first row of bearings as a whole can be obtained by superimposing them. and radial force ,

[0045] (15)

[0046] (16)

[0047] The resistance torque generated by the contact load is partly the torque generated by the axial component of the load on the bearing center O, and partly the torque generated by the radial component of the contact load on the bearing center O. The total resistance torque is for:

[0048] (17)

[0049] in, is the total axial resisting moment, is the total radial resisting moment;

[0050] By superimposing the corresponding loads of the two rows of bearings, the equilibrium equation of the bearing pair can be obtained:

[0051] (18)

[0052] In the formula, the subscript is the number of rows of corresponding bearings, M mcj is the total resisting moment generated by the j-th row bearing under the external load; M m The total resisting torque required to maintain the static balance of the bearing;

[0053] The bearing axial and radial stiffness models are obtained by solving the relationship between the displacement and load of the double-row tapered roller bearing by using the implicit function differential method, including:

[0054] According to the definition of bearing stiffness, the radial stiffness of the bearing is and axial stiffness It can be expressed by the following formula:

[0055] (19)

[0056] (20)

[0057] Solve the bearing stiffness by implicit function differentiation method:

[0058] (twenty one)

[0059] (twenty two)

[0060] Combining the above, the stiffness model is:

[0061] (twenty three)

[0062] (twenty four)

[0063] Among them, δ nijλ is the normal displacement of the j-th bearing, the i-th roller, and the λ-th slice position.

[0064] The Lundberg logarithmic profile is fitted using three arc segments by writing a MATLAB program.

[0065] After the static equilibrium equation of the double-row tapered roller bearing is established, the stress distribution analysis is carried out by writing a MATLAB program.

[0066] The calculation of the bearing axial and radial stiffness model is achieved by writing a MATLAB program.

[0067] In a second aspect, the present invention provides a hub bearing stiffness calculation device, comprising:

[0068] The arc fitting module is used to fit the Lundberg logarithmic profile using three arc segments to obtain the arc fitting roller profile;

[0069] Static balance equation establishment module, used to establish the static balance equation of double-row tapered roller bearings based on arc fitting roller profile;

[0070] The displacement and load relationship acquisition module is used to establish the displacement and load relationship of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload force by using the slicing method based on the static equilibrium equation of the double-row tapered roller bearing;

[0071] The stiffness model solving module is used to solve the relationship between the displacement and load of the double-row tapered roller bearing by using the implicit function differential method to obtain the bearing axial and radial stiffness models;

[0072] The bearing stiffness calculation module is used to input the basic bearing parameters into the bearing axial and radial stiffness models to calculate the bearing stiffness.

[0073] In a third aspect, the present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the steps of the method for calculating the stiffness of a hub bearing as described in any one of claims 1-8.

[0074] The beneficial effects of the present invention are as follows: the present invention provides a method for calculating the stiffness of a hub bearing, which uses three arc segments to fit the Lundberg logarithmic profile to obtain an arc-fitted roller profile, which is easy to process and solves the problem that the Lundberg logarithm is inconvenient to process. In addition, a slicing method is used to obtain the relationship between the displacement and load of a double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload, which can consider the influence of convexity and preload on the bearing stiffness, realize accurate calculation of the stiffness of the double-row tapered roller bearing, and provide guidance for the design of bearings and optimal bearing preload. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] Figure 1 It is the contour diagram of the three arc fitting curves in the present invention;

[0076] Figure 2 It is the force analysis diagram of the tapered roller in the present invention;

[0077] Figure 3 This is a diagram of arc fitting results of the first calculation example in Embodiment 3 of the present invention;

[0078] Figure 4 The stress distribution diagrams of three types of profile-modifying rollers in the present invention are shown below;

[0079] Figure 5 This is a curve diagram of the bearing radial stiffness change under working condition 1 in the second calculation example in embodiment 3 of the present invention;

[0080] Figure 6 This is a curve diagram of the bearing axial stiffness variation under working condition 1 in the second calculation example in embodiment 3 of the present invention;

[0081] Figure 7 This is a curve diagram of the bearing radial stiffness change under working condition 2 in the second calculation example in embodiment 3 of the present invention;

[0082] Figure 8 This is a curve diagram of the bearing axial stiffness change under working condition 2 for the second calculation example in embodiment 3 of the present invention. DETAILED DESCRIPTION

[0083] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0084] Example 1

[0085] The present invention discloses a method for calculating the stiffness of a hub bearing, comprising the following steps:

[0086] Step 1: Fit the Lundberg logarithmic profile with three arc segments to obtain an arc fitting roller profile.

[0087] Step 2: Establish the static equilibrium equation of the double-row tapered roller bearing based on the arc fitting roller profile.

[0088] Step three, based on the static equilibrium equation of the double-row tapered roller bearing, the slicing method is used to obtain the relationship between the displacement and load of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload.

[0089] Step 4: The relationship between the displacement and load of the double-row tapered roller bearing is solved by the implicit function differential method to obtain the bearing axial and radial stiffness models.

[0090] Step 5: Input the basic parameters of the bearing into the bearing axial and radial stiffness models to calculate the bearing stiffness.

[0091] The present invention provides a method for fitting a Lundberg logarithmic profile using three arc segments to obtain an arc fitting roller profile, which is easy to process and solves the problem that the Lundberg logarithm is inconvenient to process. In addition, a slicing method is used to obtain the relationship between the displacement and load of a double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload force, so that the influence of the preload force on the bearing stiffness can be considered, and the stiffness of the double-row tapered roller bearing can be accurately calculated, which can provide guidance for the design of the bearing and the optimal preload force of the bearing.

[0092] Example 2

[0093] The present invention discloses a method for calculating the stiffness of a hub bearing, comprising the following steps:

[0094] Step 1: Fit the Lundberg logarithmic profile with three arc segments to obtain an arc fitting roller profile.

[0095] The curve function of the Lundberg logarithmic roller surface profile is:

[0096] (1)

[0097] Where x is the position along the roller generatrix, y1 is the training value, is the Poisson's ratio of the material, E is the elastic modulus of the roller, Q is the maximum force of the roller during roller modification design, is the effective contact length of the roller;

[0098] Figure 1For the three arc fitting curve contours, according to Figure 1 The arc coordinates are:

[0099] (2)

[0100] In the figure, point C is the radius R 1 The intersection of the three arcs with radius R2. There are two intersection points. y2 is the training value after fitting, 2c is the distance between the intersection points of the two arcs, R1 is the radius of the middle arc, and R2 is the radius of the two side arcs.

[0101] Judging from the stress distribution, the arc fitting roller profile can solve both the linear stress concentration phenomenon and the inconvenient processing problem of the Lundberg logarithmic roller profile.

[0102] Step 2: Establish the static equilibrium equation of the double-row tapered roller bearing based on the arc fitting roller profile.

[0103] Under the action of external load, the tapered roller is subjected to Figure 2 As shown, the contact between the inner ring and the rolling element is taken as the analysis object, and the static equilibrium equation is:

[0104] (3)

[0105] Considering the inner ring and roller as a whole, the first row of bearings is analyzed. Under the action of external force, the axial displacement between the inner ring and the outer ring of the bearing is , radial displacement and normal displacement have:

[0106] (4)

[0107] in, Respectively represent the contact force between the rolling element and the outer raceway, inner raceway and flange, Respectively represent the contact angles between the rolling element and the outer raceway, inner raceway and rib;

[0108] No. The normal displacement between the outer rings of the bearings at each roller is:

[0109] (5)

[0110] In the formula For the Roller azimuth,

[0111] (6)

[0112] Wherein, Z is the number of rollers in a single-row bearing;

[0113] If an axial preload is applied, the axial predeformation for:

[0114] (7)

[0115] (8)

[0116] In the formula is the roller finite contact length, is the average roller diameter;

[0117] Assume the center distance between the two rows of bearings is d c , the bearing center pitch diameter is d m , at this time, the total axial displacement and radial displacement are:

[0118] (9)

[0119] (10)

[0120] Where θ is the angle between the inner and outer rings under the action of external load.

[0121] Step three, based on the static equilibrium equation of the double-row tapered roller bearing, the slicing method is used to obtain the relationship between the displacement and load of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload.

[0122] When analyzing the deformation of a tapered roller with convexity, the slicing method is used. The roller repair amount is equivalent to the negative normal displacement of the roller. The roller contacts the raceway only after the repair amount is offset at the slicing point. Roller, The normal displacement of the slice position for:

[0123] (11)

[0124] (12) (13)

[0125] So the The total contact force of the rollers is:

[0126] (14)

[0127] Where For the The number of slices on which each roller is loaded, n is the number of slices on each roller;

[0128] The above obtained The normal contact force of each roller is decomposed into axial force and radial force, and then the axial force of the first row of bearings as a whole can be obtained by superimposing them. and radial force ,

[0129] (15)

[0130] (16)

[0131] The resistance torque generated by the contact load is partly the torque generated by the axial component of the load on the bearing center O, and partly the torque generated by the radial component of the contact load on the bearing center O. The total resistance torque is for:

[0132] (17)

[0133] in, is the total axial resisting moment, is the total radial resisting moment;

[0134] By superimposing the corresponding loads of the two rows of bearings, the equilibrium equation of the bearing pair can be obtained:

[0135] (18)

[0136] In the formula, the subscript is the number of rows of corresponding bearings, M mcj is the total resisting moment generated by the j-th row bearing under the external load; M m The total resisting torque required to maintain the static balance of the bearing;

[0137] Step 4: The relationship between the displacement and load of the double-row tapered roller bearing is solved by the implicit function differential method to obtain the bearing axial and radial stiffness models.

[0138] Because there is a nonlinear relationship between radial load and radial displacement, and between axial load and axial displacement, the stiffness of the bearing cannot be directly expressed by derivative. However, because there is a nonlinear relationship between radial load and radial displacement, and between axial load and axial displacement, The bearing stiffness can be solved by implicit function differentiation method.

[0139] According to the definition of bearing stiffness, the radial stiffness of the bearing is and axial stiffness It can be expressed by the following formula:

[0140] (19)

[0141] (20)

[0142] Solve the bearing stiffness by implicit function differentiation method:

[0143] (twenty one)

[0144] (twenty two)

[0145] Combining the above, the stiffness model is:

[0146] (twenty three)

[0147] (twenty four)

[0148] Among them, δ nijλ is the normal displacement of the j-th bearing, the i-th roller, and the λ-th slice position.

[0149] Step 5: Input the basic parameters of the bearing into the bearing axial and radial stiffness models to calculate the bearing stiffness.

[0150] The above calculation process in the present invention will be implemented using MATLAB programming.

[0151] Example 3

[0152] To more specifically illustrate the effectiveness of the method, the present invention provides two calculation examples.

[0153] The parameters of the first calculation example are shown in Table 1.

[0154] Table 1 Bearing parameters

[0155]

[0156] The optimal fitting results of arc fitting for the bearing parameters in Table 1 are shown in Table 2, and the fitting curve is shown in Figure 3 .

[0157] Table 2 Optimal fitting results

[0158]

[0159] Figure 4 The load Q for the Lundberg logarithmic roller modification is 55973N. The stress distribution diagrams of three modified profiles, namely, linear type without modification, Lundberg logarithmic type, and arc fitting type, are obtained by using the slicing method. It is assumed that the linear roller produces a displacement of 0.01mm under the action of external force. Figure 4 It can be seen that the arc fitting roller can effectively eliminate the stress concentration phenomenon.

[0160] The parameters of the second calculation example are shown in Table 3. The fitting results of the bearing parameters in Table 3 are c=12.169mm, R1=12319mm, and R2=2051mm.

[0161] Table 3 Bearing parameters

[0162]

[0163] In working condition 1: radial load is 30KN, bending moment load is 20N·m, axial load is 0N, preload force increases from 0N to 30kN, bearing stiffness change trend is as follows Figure 5 and Figure 6 ,from Figure 5 and Figure 6 It can be seen that when the preload force is small, the radial and axial stiffness of the bearing increases slowly with the preload force. When the preload force reaches a certain value and continues to increase, the axial and radial stiffness of the bearing increases rapidly. If the preload force continues to increase, the increasing trend of the axial and radial stiffness will decrease. This is because as the preload force increases, the number of rollers under stress also gradually increases. When all rollers are under stress, the trend of stiffness increase slows down.

[0164] In working condition 2: radial load 50000N, bending moment load 20N·m, axial load 20000N, preload 1000N, roller generatrix modification design load from 0-60000N. The bearing stiffness change curve is as follows Figure 7 and Figure 8 .from Figure 7 It can be obtained that when the roller busbar modification design load is 0N, the stiffness of the roller busbar with a straight line is much smaller than that of the roller busbar with a modified shape, which means that the roller busbar modification can increase the stiffness of the bearing. The trend of the bearing stiffness change under different roller busbar modification amounts is uncertain, which means that there is an optimal modification amount for the roller busbar.

[0165] It can be seen from the above that the present invention can accurately determine the preload force required to be loaded on the bearing and the optimal convexity of the roller within a certain range by using the stiffness model.

[0166] Example 4

[0167] This embodiment discloses a hub bearing stiffness calculation device, comprising:

[0168] The arc fitting module is used to fit the Lundberg logarithmic profile using three arc segments to obtain the arc fitting roller profile;

[0169] Static balance equation establishment module, used to establish the static balance equation of double-row tapered roller bearings based on arc fitting roller profile;

[0170] The displacement and load relationship acquisition module is used to establish the displacement and load relationship of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload force by using the slicing method based on the static equilibrium equation of the double-row tapered roller bearing;

[0171] The stiffness model solving module is used to solve the relationship between the displacement and load of the double-row tapered roller bearing by using the implicit function differential method to obtain the bearing axial and radial stiffness models;

[0172] The bearing stiffness calculation module is used to input the basic bearing parameters into the bearing axial and radial stiffness models to calculate the bearing stiffness.

[0173] Example 5

[0174] This embodiment discloses a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method described in Embodiment 1 or 2 are executed.

[0175] It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Furthermore, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0176] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0177] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0178] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0179] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for calculating wheel hub bearing stiffness, characterized in that: The following steps are involved: The Lundberg logarithmic profile is fitted with three arc segments to obtain the arc fitting roller profile. The static equilibrium equation of double-row tapered roller bearing is established based on the arc fitting roller profile; Based on the static equilibrium equation of double-row tapered roller bearings, the slice method is used to obtain the relationship between the displacement and load of double-row tapered roller bearings under the action of radial load, axial load and torque considering the preload. The relationship between displacement and load of double-row tapered roller bearing is solved by implicit function differential method to obtain the axial and radial stiffness model of the bearing. The basic bearing parameters are input into the bearing axial and radial stiffness models to calculate the bearing stiffness.

2. The method for calculating the stiffness of a hub bearing according to claim 1, characterized in that: The method of fitting the Lundberg logarithmic profile roller using three arc segments to obtain the arc fitting roller profile includes: The curve function of the Lundberg logarithmic roller surface profile is: （1） Where x is the position along the roller generatrix, y1 is the training value, is the Poisson's ratio of the material, E is the elastic modulus of the roller, Q is the maximum force of the roller during roller modification design, is the effective contact length of the roller; The curve function of the three arc fitting curve contour is: （2） Where y2 is the training value after fitting, 2c is the distance between the intersection points of the two arc segments, R1 is the radius of the middle arc segment, and R2 is the radius of the arc segments on both sides.

3. The method for calculating the stiffness of a hub bearing according to claim 2, characterized in that: The static balance equation of the double-row tapered roller bearing established based on the arc fitting roller profile includes: Taking the contact between the inner ring and the rolling element as the analysis object, the static equilibrium equation is: （3） Considering the inner ring and roller as a whole, the first row of bearings is analyzed. Under the action of external force, the axial displacement between the inner ring and the outer ring of the bearing is , radial displacement and normal displacement have: （4） in, Respectively represent the contact force between the rolling element and the outer raceway, inner raceway and flange, Respectively represent the contact angles between the rolling element and the outer raceway, inner raceway and rib; No. The normal displacement between the outer rings of the bearings at each roller is: （5） In the formula For the Roller azimuth, （6） Wherein, Z is the number of rollers in a single-row bearing; If an axial preload is applied, the axial predeformation for: （7） （8） In the formula is the roller finite contact length, is the average roller diameter; Assume the center distance between the two rows of bearings is d c , the bearing center pitch diameter is d m , at this time, the total axial displacement and radial displacement are: （9） （10） Where θ is the rotation angle between the inner and outer rings under the action of external load.

4. The method for calculating the stiffness of a hub bearing according to claim 3, characterized in that: The relationship between the displacement and load of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload force is established by using the slice method based on the static balance equation of the double-row tapered roller bearing, including: When analyzing the deformation of a tapered roller with convexity, the slicing method is used. The roller repair amount is equivalent to the negative normal displacement of the roller. The roller contacts the raceway only after the repair amount is offset at the slicing point. Roller, The normal displacement of the slice position for: （11） （12） （13） So the The total contact force of the rollers is: （14） Where For the The number of slices on which each roller is loaded, n is the number of slices per roller; The above obtained The normal contact force of each roller is decomposed into axial force and radial force, and then the axial force of the first row of bearings as a whole can be obtained by superimposing them. and radial force , (15) （16） The resistance torque generated by the contact load is partly the torque generated by the axial component of the load on the bearing center O, and partly the torque generated by the radial component of the contact load on the bearing center O. The total resistance torque is for: （17） in, is the total axial resisting moment, is the total radial resisting moment; By superimposing the corresponding loads of the two rows of bearings, the equilibrium equation of the bearing pair can be obtained: （18） In the formula, the subscript is the number of rows of corresponding bearings, M mcj is the total resisting moment generated by the j-th row bearing under the external load; M m The total resisting torque required to maintain the static balance of the bearing.

5. The method for calculating the stiffness of a hub bearing according to claim 4, characterized in that: The bearing axial and radial stiffness models are obtained by solving the relationship between the displacement and load of the double-row tapered roller bearing by using the implicit function differential method, including: According to the definition of bearing stiffness, the radial stiffness of the bearing is and axial stiffness It can be expressed by the following formula: （19） （20） Solve the bearing stiffness by implicit function differentiation method: （21） （22） Combining the above, the stiffness model is: （23） （24） Among them, δ nijλ is the normal displacement of the j-th bearing, the i-th roller, and the λ-th slice position.

6. The method for calculating the stiffness of a hub bearing according to claim 1, characterized in that: The Lundberg logarithmic profile is fitted using three arc segments by writing a MATLAB program.

7. The method for calculating the stiffness of a hub bearing according to claim 3, characterized in that: After the static equilibrium equation of the double-row tapered roller bearing is established, the stress distribution analysis is carried out by writing a MATLAB program.

8. The method for calculating the stiffness of a hub bearing according to claim 5, characterized in that: The calculation of the bearing axial and radial stiffness model is achieved by writing a MATLAB program.

9. A wheel hub bearing stiffness calculation device, characterized in that: include; The arc fitting module is used to fit the Lundberg logarithmic profile using three arc segments to obtain the arc fitting roller profile; Static balance equation establishment module, used to establish the static balance equation of double-row tapered roller bearings based on arc fitting roller profile; The displacement and load relationship acquisition module is used to establish the displacement and load relationship of the double-row tapered roller bearing under the action of radial load, axial load and torque considering the preload force by using the slicing method based on the static equilibrium equation of the double-row tapered roller bearing; The stiffness model solving module is used to solve the relationship between the displacement and load of the double-row tapered roller bearing by using the implicit function differential method to obtain the bearing axial and radial stiffness models; The bearing stiffness calculation module is used to input the basic bearing parameters into the bearing axial and radial stiffness models to calculate the bearing stiffness.

10. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instruction is executed by a processor, the steps of the method for calculating the stiffness of a hub bearing described in any one of claims 1-8 are implemented.

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