A vibration evaluation method for four-point contact ball bearings under preload

Abstract

The present invention relates to a method for evaluating the vibration of a four-point contact ball bearing under a preload, and belongs to the technical field of bearing vibration detection. Because it is difficult to evaluate the vibration of a four-point contact ball bearing under a preload, the present invention calculates the working contact angle of the bearing under a preload based on the geometric characteristics of the four-point contact ball bearing. The center of curvature of the outer ring groove of the outer ring before vibration is determined based on the working contact angle. The outer ring is displaced when subjected to the preload, and a force analysis is performed based on the position of the center of curvature of the outer ring groove before and after vibration. A vibration equation is established based on the force applied to the outer ring, and the vibration equation is solved to obtain the radial vibration acceleration of the bearing. The vibration of the bearing under a preload is then evaluated based on the radial vibration acceleration.

Description

Technical Field

[0001] The invention relates to a vibration evaluation method for a four-point contact ball bearing under a preload, and belongs to the technical field of bearing vibration detection. Background Art

[0002] As a key component in power transmission mechanisms, four-point contact bearings are increasingly used in these applications due to their ability to withstand bidirectional axial loads. The performance of four-point contact ball bearings directly impacts the efficiency and reliability of the entire transmission mechanism. In addition to meeting longevity requirements, the design of four-point contact ball bearings also requires increasingly stringent control of bearing vibration and noise. Addressing bearing design is one effective method for reducing bearing vibration and noise.

[0003] Currently, most research on rolling bearing vibration mechanisms is based on the relationship between bearing manufacturing error waviness and bearing vibration. This research focuses on deep groove ball bearings and cylindrical roller bearings, making it difficult to directly transfer research methods for these bearings to four-point contact ball bearings. Therefore, a method for evaluating the vibration of running four-point contact ball bearings under preload is urgently needed to facilitate vibration and noise control during four-point contact ball bearing design. Summary of the Invention

[0004] The object of the present invention is to provide a vibration evaluation method for a four-point contact ball bearing under a preload, so as to solve the problem that it is difficult to evaluate the vibration of a four-point contact ball bearing under a preload.

[0005] In order to achieve the above object, the present invention provides a vibration evaluation method for a four-point contact ball bearing under a preload, comprising the following steps:

[0006] S1. Determine the working contact angle of the four-point contact ball bearing under the action of preload based on the geometric relationship of the four-point contact ball bearing;

[0007] S2. Determine the center of curvature of the outer ring groove of the four-point contact ball bearing before vibration occurs based on the working contact angle;

[0008] S3. Based on the change in the center position of the outer ring groove curvature before and after the outer ring vibrates, a vibration equation is established to characterize the force acting on the outer ring during vibration, and the vibration equation is solved to obtain the radial vibration acceleration of the bearing. The vibration equation is established by establishing a vibration coordinate system of the four-point contact ball bearing with the center of the four-point contact ball bearing as the origin and the axial direction of the four-point contact ball bearing as the Z direction. Based on the working contact angle, the center position of the inner ring groove curvature before the outer ring vibrates is determined, and the vibration equation is established based on the center position of the inner ring groove curvature and the change in the center position of the outer ring groove curvature before and after the outer ring vibrates.

[0009] S4. Evaluate the vibration magnitude of the four-point contact ball bearing under the action of the preload force based on the radial vibration acceleration.

[0010] Since it is difficult to evaluate the vibration of a four-point contact ball bearing under preload, the present invention calculates the working contact angle of the bearing under preload according to the geometric characteristics of the four-point contact ball bearing by establishing a mathematical model and solving mathematical problems. The position of the center of curvature of the outer ring groove of the outer ring before vibration is determined based on the working contact angle. The outer ring is displaced when subjected to the preload. A force analysis is performed based on the position of the center of curvature of the outer ring groove before and after vibration. A vibration equation is established based on the force conditions of the outer ring. The vibration equation is solved to obtain the radial vibration acceleration of the bearing. The vibration of the bearing under preload is evaluated based on the radial vibration acceleration.

[0011] Furthermore, in the above method, the vibration equation is expressed by the following formula:

[0012]

[0013] Where m is the mass of the outer ring of the four-point contact ball bearing, is the radial vibration acceleration of the bearing in the X-axis direction, is the radial vibration acceleration of the bearing in the Y-axis direction, is the axial vibration acceleration of the bearing, is the radial velocity of the bearing in the X-axis, is the radial velocity of the bearing in the Y-axis direction, is the bearing axial speed, c x is the component of the total damping of the lubricating oil in the X-axis direction, c y is the component of the total damping of the lubricating oil in the Y-axis direction, c z is the component of the total damping of the lubricating oil in the Z-axis direction, F x is the component of the Herzt contact force between the steel ball and the outer ring in the X-axis direction, F y is the component of the Herzt contact force between the steel ball and the outer ring in the Y-axis direction, F z is the component of the Herzt contact force between the steel ball and the outer ring in the Z-axis direction, g is the acceleration of gravity, and Fa is the axial preload applied to the bearing.

[0014] Furthermore, in the above method, c x 、c y and c z It is expressed by the following formula:

[0015]

[0016] Where c is the total damping of the lubricating oil when the steel balls of the four-point contact ball bearing roll, N is the number of steel balls, and α is j is the working contact angle, 1<<j<<N.

[0017] Furthermore, in the above method, in step S1, the working contact angle α is obtained by solving the following formula: j :

[0018]

[0019] Where K n is the total load-deformation coefficient between the steel ball and the inner and outer rings of the four-point contact ball bearing, B = f i +f e -1,f i is the curvature radius coefficient of the inner ring groove of the four-point contact ball bearing, f e D is the curvature radius coefficient of the outer ring groove of the four-point contact ball bearing. w is the diameter of the steel ball, α 0 is the original contact angle, α j is the working contact angle of the bearing, Fa is the axial preload force on the bearing, N is the number of steel balls, 1<<j<<N.

[0020] Furthermore, in the above method, the original contact angle α is obtained by solving the following formula: 0 :

[0021]

[0022] Where r i is the radius of curvature of the inner groove, r e is the outer groove curvature radius, x i is the eccentricity of the inner groove curvature center, x e G is the eccentricity of the center of curvature of the outer ring groove. r is the radial clearance of the four-point contact ball bearing, D w is the diameter of the steel ball.

[0023] Furthermore, in the above method, the total load-deformation coefficient K between the steel ball and the inner and outer rings of the four-point contact ball bearing is n Calculated by the following formula:

[0024]

[0025] Where K i K is the load-deformation coefficient of the steel ball and the inner ring, e is the load-deformation coefficient of the steel ball and outer ring.

[0026] Furthermore, in the above method, in step S4, the vibration acceleration level L is calculated according to the radial vibration acceleration using the following formula, and the vibration magnitude of the four-point contact ball bearing under preload is evaluated by the vibration acceleration level L:

[0027]

[0028] Where, is the root mean square value of radial vibration acceleration, N is the number of steel balls, is the radial vibration acceleration of the bearing, A0 is the vibration standard reference value, which is taken as 9.81×10 -3 m / s 2 .

[0029] The vibration condition can be quantitatively evaluated through the vibration acceleration level for easy observation.

[0030] Furthermore, the above method also includes: determining the radial vibration acceleration of the four-point contact ball bearing under different radial clearances, and evaluating the vibration magnitude of the four-point contact ball bearing under the action of preload based on the radial vibration acceleration corresponding to the different radial clearances.

[0031] By calculating the vibration acceleration under different radial clearances, the vibration conditions of the bearing under different radial clearances can be evaluated and analyzed, which can guide the bearing design and obtain four-point contact ball bearings with smaller vibrations. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A flowchart of a four-point contact ball bearing vibration evaluation method in an embodiment of the present invention;

[0033] Figure 2 Schematic diagram of the change of contact angle of a four-point contact ball bearing under the action of preload in an embodiment of the method of the present invention;

[0034] Figure 3 A YOZ plane schematic diagram of a vibration coordinate system of a four-point contact ball bearing in an embodiment of the method of the present invention;

[0035] Figure 4 Schematic diagram of the XOY plane of the vibration coordinate system of the four-point contact ball bearing in the embodiment of the method of the present invention;

[0036] Figure 5 Graph showing bearing vibration acceleration signals of a four-point ball contact bearing in an embodiment of the method of the present invention when the clearances are 45 μm, 65 μm, and 85 μm respectively;

[0037] Figure 6 Schematic diagram of bearing vibration acceleration levels of a four-point contact ball bearing under different clearances in an embodiment of the method of the present invention. DETAILED DESCRIPTION

[0038] In order to make the objectives, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0039] Method Example:

[0040] like Figure 1 As shown, the method for evaluating the vibration of a four-point contact ball bearing under a preload force of the present invention comprises the following steps:

[0041] S1. Obtain structural parameters and lubrication parameters of a four-point contact ball bearing and establish a geometric model of the four-point contact ball bearing.

[0042] S2. According to the geometric relationship of the four-point contact ball bearing, the original contact angle α of the bearing is calculated by the following formula: o :

[0043]

[0044] Where r i is the radius of curvature of the inner groove, r e is the outer groove curvature radius, x i is the eccentricity of the inner groove curvature center, x e G is the eccentricity of the center of curvature of the outer ring groove. r is the radial clearance of the four-point contact ball bearing, D w is the diameter of the steel ball.

[0045] When the bearing is subjected to external load, the contact angle of the bearing is called the working contact angle. The raceway of the four-point contact ball bearing is composed of four arcs. When the bearing is subjected to axial preload, the steel ball contacts an arc of the inner ring raceway and an arc of the outer ring raceway in the opposite direction, such as Figure 2 As shown in the figure, the inner ring of the bearing undergoes axial displacement at this time. Figure 2 Medium α j is the working contact angle of the bearing, k is the center of curvature of the groove of the outer ring, m and m′ are the centers of curvature of the groove of the left inner ring before and after the contact angle changes, E and E′ are the contact points between the steel ball and the left inner ring before and after the contact angle changes, H and H′ are the contact points between the steel ball and the outer ring before and after the contact angle changes.

[0046] The axial displacement δ of the bearing inner ring is calculated using the following formula:

[0047]

[0048] Where B = f i +f e -1,f i is the curvature radius coefficient of the inner ring groove of the four-point contact ball bearing, fe D is the curvature radius coefficient of the outer ring groove of the four-point contact ball bearing. w is the diameter of the steel ball, α 0 is the original contact angle, α j is the working contact angle of the bearing.

[0049] According to Hertz contact theory, the contact load Q between the steel ball and the ring is calculated by the following formula:

[0050]

[0051] Where K n is the total load-deformation coefficient between the steel ball and the inner and outer rings of the four-point contact ball bearing, B = f i +f e -1,f i is the curvature radius coefficient of the inner ring groove of the four-point contact ball bearing, f e D is the curvature radius coefficient of the outer ring groove of the four-point contact ball bearing. w is the diameter of the steel ball, α 0 is the original contact angle, α j is the working contact angle of the bearing.

[0052] When a four-point contact ball bearing is subjected to an axial preload, the load on each ball is evenly distributed, and the contact load Q between the ball and the ring can be expressed by the following formula:

[0053]

[0054] Where Fa is the axial preload force on the bearing and N is the number of steel balls.

[0055] Combining formula (3) and formula (4), we get the transcendental equation of contact angle:

[0056]

[0057] Combine formulas (1) and (5), substitute the structural parameters, material parameters and preload of the four-point contact ball bearing into the formula to solve, and the working contact angle α of the bearing after loading can be calculated. j .

[0058] Total load-deformation coefficient K between the steel ball and the inner and outer rings of the four-point contact ball bearing n Calculated by the following formula:

[0059]

[0060] Where K i K is the load-deformation coefficient of the steel ball and the inner ring, e is the load-deformation coefficient of the steel ball and outer ring.

[0061] Load-deformation coefficient K of steel ball and inner ring i and the load-deformation coefficient K of the steel ball and outer ring e It is expressed by the following formula:

[0062] K i =2.15×10 5 (∑i) -0.5 n δi -1.5 (7)

[0063] K e =2.15×10 5 (∑e) -0.5 n δe -1.5 (8)

[0064] Where ∑i and ∑e are the principal curvatures of the steel ball, inner ring, and outer ring, respectively, and are calculated using the following formula:

[0065]

[0066] is the contact deformation coefficient between the steel ball and the inner ring, is the elastic deformation coefficient of the steel ball and the outer ring, which is expressed by the following formula:

[0067]

[0068] Where, F i and F e are the principal curvature difference functions of the steel ball, inner ring, and outer ring, respectively, and are calculated using the following formula:

[0069]

[0070] S3. According to Hertz contact theory, the semi-major axis a of the contact ellipse between the steel ball and the inner and outer rings is obtained. i and a e .

[0071] S4. According to the calculation method of point contact elastohydrodynamic oil film thickness under isothermal conditions derived by Hamrock and Dowson, the minimum oil film thickness h between the steel ball and the ring is: 0j The calculation formula is:

[0072]

[0073] Where, α u is the pressure index of the lubricating oil viscosity, η0 is the kinematic viscosity of the lubricating oil, u is the average velocity of the two contact surfaces, R xis the equivalent radius of curvature along the rolling direction of the steel ball, K is the ellipticity, n is the speed of the bearing inner ring, γ=D w cosα j / d m , is a dimensionless parameter, f j is the groove curvature radius coefficient of the inner and outer rings of the bearing, Q is the contact load between the steel ball and the ring, E0 is the equivalent elastic modulus, d m is the pitch diameter of the bearing.

[0074] The high pressure makes the oil film in the Hertz contact area completely rigid, so the damping of the Hertz contact area is ignored. The damping of the lubricating oil mainly comes from the inlet area of ​​the oil film. The calculation formula of the lubricating oil damping c is:

[0075]

[0076] Combining formulas (15)-(20), when j in formulas (15), (19) and (20) is i, a j is the semi-major axis a of the contact ellipse between the steel ball and the inner ring i , the lubricating oil damping c when the steel ball contacts the inner ring to form a lubricating oil film can be calculated i , when j in formulas (15), (19) and (20) is e, a j is the semi-major axis a of the contact ellipse between the steel ball and the outer ring e , the lubricating oil damping c when the steel ball contacts the outer ring to form a lubricating oil film can be calculated e .

[0077] Considering that a single steel ball contacts the inner and outer rings at the same time to form a lubricating oil film, the total damping of the lubricating oil is composed of the oil films of the inner and outer rings. The total damping c of the lubricating oil is calculated by the following formula:

[0078]

[0079] The calculation formula for the oil film damping of the entire four-point ball bearing is:

[0080]

[0081] Where c is the total damping of the lubricating oil when the steel balls of the four-point contact ball bearing roll, N is the number of steel balls, and α is j is the working contact angle, 1<<j<<N.

[0082] S5, such as Figure 3 and Figure 4As shown in the figure, the steel ball of the four-point contact ball bearing is regarded as a massless nonlinear spring, and the contact between the steel ball and the two raceways is regarded as a free mass point connected to a certain mass. The vibration coordinate system of the four-point contact ball bearing is established, where O-XYZ is a fixed coordinate system used to determine the initial position of the bearing parts, and O-nτ is a natural coordinate system used to describe the angular position of the steel ball. Figure 3 As shown in the figure, the position vectors of the inner and outer ring groove curvature centers before the outer ring is displaced are:

[0083]

[0084] Where θ j is the angle between the jth steel ball and the Y axis after rotating for t time, θ j =ω c t+2π(j-1) / N,R i =0.5(d m +B d cosα j ), R e =0.5(d m -B d cosα j ), Z e -Z i =B d sinα j , B d =r i +r e -D w -G r cosα j ,ω c is the angular velocity of the cage; Z i and Z e are the initial positions of the inner and outer raceway curvature centers, B d It is the initial distance between the centers of curvature of the inner and outer ring grooves of the four-point contact ball bearing before the outer ring vibrates.

[0085] According to the GB / T32333 standard for bearing vibration measurement, ball bearings only bear axial preload during vibration measurement. Therefore, the displacement of the outer ring in three directions is considered, namely the linear displacement x along the X-axis, the linear displacement y along the Y-axis, and the linear displacement z along the Z-axis. The rotational displacement θ along the X-axis is not considered. x and the rotational displacement θ along the Y axis y , that is, θ x =θ y =0, the position vectors of the inner and outer ring groove curvature centers are:

[0086]

[0087] The transformation matrix T is:

[0088]

[0089] The position vectors of the center of curvature of the inner and outer ring grooves become:

[0090]

[0091] make

[0092]

[0093] vector The direction angles of the vector Angle with the X axis Angle ψ with the Y axis j and the angle χ with the z-axis j , which is expressed by the following formula:

[0094]

[0095] After considering the vibration of the outer ring, the distance between the centers of curvature of the inner and outer ring grooves is:

[0096]

[0097] Elastic deformation δ of the jth steel ball j That is, the difference in the distance between the center of curvature of the inner and outer ring grooves before and after the outer ring vibration:

[0098] δ j =B′ d +h 0i +h 0e -B d

[0099] Where B′ d h is the distance between the centers of curvature of the inner and outer ring grooves after the outer ring vibrates. 0i h is the minimum oil film thickness between the steel ball and the inner ring, 0e B is the minimum oil film thickness between the steel ball and the outer ring. d It is the initial distance between the centers of curvature of the inner and outer ring grooves before the outer ring vibrates.

[0100] Then the Herzt contact force F between the jth steel ball and the outer ring is j becomes:

[0101]

[0102] Where K n is the total load-deformation coefficient between the steel ball and the inner and outer rings of the four-point contact ball bearing, δ j It is the difference in the distance between the center of curvature of the inner and outer ring grooves before and after the outer ring vibration.

[0103] The component F of the sum of the Herzt contact forces between all the balls and the outer ring in the X-axis, Y-axis, and Z-axis directions x 、F y 、F z It can be expressed as:

[0104]

[0105] Then the nonlinear vibration equation of the four-point contact ball bearing under the action of preload is:

[0106]

[0107] Where m is the mass of the outer ring of the four-point contact ball bearing, is the radial vibration acceleration of the bearing in the X-axis direction, is the radial vibration acceleration of the bearing in the Y-axis direction, is the axial vibration acceleration of the bearing, is the radial velocity of the bearing in the X-axis, is the radial velocity of the bearing in the Y-axis direction, is the bearing axial speed, c x is the component of the total damping of the lubricating oil in the X-axis direction, c y is the component of the total damping of the lubricating oil in the Y-axis direction, c z is the component of the total damping of the lubricating oil in the Z-axis direction, F x is the component of the Herzt contact force between the steel ball and the outer ring in the X-axis direction, F y is the component of the Herzt contact force between the steel ball and the outer ring in the Y-axis direction, F z is the component of the Herzt contact force between the steel ball and the outer ring in the Z-axis direction, g is the acceleration of gravity, and Fa is the axial preload applied to the bearing.

[0108] S6. Define the starting time, ending time and solution step size of the solution, solve the vibration equation of the four-point contact ball bearing, and obtain the radial vibration acceleration signal of the bearing

[0109] Change the radial clearance value of the four-point contact ball bearing, repeat the above steps, and draw the vibration acceleration signal diagram of the four-point contact ball bearing under different radial clearances.

[0110] S7. Use the vibration acceleration level L to evaluate the magnitude of bearing vibration. The calculation formula is as follows:

[0111]

[0112] Where, is the root mean square value of radial vibration acceleration, A0 is the vibration standard reference value, which is taken as 9.81×10 -3 m / s 2 .

[0113] Taking a certain type of four-point contact ball bearing as an example, the method of the present invention is verified. The structural parameters and lubricating oil parameters of the bearing are as follows:

[0114] d m =97.5mm, r i =9.03mm, r e =9.24mm, N=15, D w =17.463mm, G r =75μm,

[0115] α u =2.21×10 -8 Pa -1 , eta0=0.06338Pa·s, Fa=3310N, n=2300r / min.

[0116] According to the above steps S1-S7, draw Figure 5 The vibration acceleration signal diagram of the four-point contact ball bearing under different radial clearances shown in the figure, and Figure 6 The vibration acceleration level diagram of the four-point contact ball bearing under different radial clearances is shown in the figure, so as to evaluate the vibration of the bearing under preload. Figure 6 It can be seen from the figure that the bearing vibration acceleration level increases with the increase of radial clearance.

[0117] By adopting the present invention, the vibration of the bearing under preload can be evaluated according to the geometric characteristics of different four-point contact ball bearings. The evaluation results can be used to guide the bearing design, thereby designing a low-vibration four-point contact ball bearing.

Claims

1. A vibration evaluation method for a four-point contact ball bearing under preload, characterized in that: The steps include: S1. Determine the working contact angle of the four-point contact ball bearing under the action of preload based on the geometric relationship of the four-point contact ball bearing; S2. Determine the center of curvature of the outer ring groove of the four-point contact ball bearing before vibration occurs based on the working contact angle; S3. Based on the change in the center position of the outer ring groove curvature before and after the outer ring vibrates, a vibration equation is established to characterize the force acting on the outer ring during vibration, and the vibration equation is solved to obtain the radial vibration acceleration of the bearing. The vibration equation is established by establishing a vibration coordinate system of the four-point contact ball bearing with the center of the four-point contact ball bearing as the origin and the axial direction of the four-point contact ball bearing as the Z direction. Based on the working contact angle, the center position of the inner ring groove curvature before the outer ring vibrates is determined, and the vibration equation is established based on the center position of the inner ring groove curvature and the change in the center position of the outer ring groove curvature before and after the outer ring vibrates. S4. Evaluate the vibration magnitude of the four-point contact ball bearing under the action of the preload force based on the radial vibration acceleration.

2. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 1, characterized in that: The vibration equation is expressed by the following formula: Where m is the mass of the outer ring of the four-point contact ball bearing, is the radial vibration acceleration of the bearing in the X-axis direction, is the radial vibration acceleration of the bearing in the Y-axis direction, is the axial vibration acceleration of the bearing, is the radial velocity of the bearing in the X-axis, is the radial velocity of the bearing in the Y-axis direction, is the bearing axial speed, c x is the component of the total damping of the lubricating oil in the X-axis direction, c y is the component of the total damping of the lubricating oil in the Y-axis direction, c z is the component of the total damping of the lubricating oil in the Z-axis direction, F x is the component of the Herzt contact force between the steel ball and the outer ring in the X-axis direction, F y is the component of the Herzt contact force between the steel ball and the outer ring in the Y-axis direction, F z is the component of the Herzt contact force between the steel ball and the outer ring in the Z-axis direction, g is the acceleration of gravity, and Fa is the axial preload force on the bearing.

3. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 2, characterized in that: c x 、c y and c z It is expressed by the following formula: Where c is the total damping of the lubricating oil when the steel balls of the four-point contact ball bearing roll, N is the number of steel balls, and α is j is the working contact angle, 1<<j<<N.

4. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 1, characterized in that: In step S1, the working contact angle α is obtained by solving the following formula: j : Where K n is the total load-deformation coefficient between the steel ball and the inner and outer rings of the four-point contact ball bearing, B = f i +f e -1,f i is the curvature radius coefficient of the inner ring groove of the four-point contact ball bearing, f e D is the curvature radius coefficient of the outer ring groove of the four-point contact ball bearing. w is the diameter of the steel ball, α 0 is the original contact angle, α j is the working contact angle of the bearing, Fa is the axial preload force on the bearing, N is the number of steel balls, 1<<j<<N.

5. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 4, characterized in that: The original contact angle α is obtained by solving the following formula 0 : Where r i is the radius of curvature of the inner groove, r e is the outer groove curvature radius, x i is the eccentricity of the inner groove curvature center, x e G is the eccentricity of the center of curvature of the outer ring groove. r is the radial clearance of the four-point contact ball bearing, D w is the diameter of the steel ball.

6. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 4, characterized in that: Total load-deformation coefficient K between the steel ball and the inner and outer rings of the four-point contact ball bearing n Calculated by the following formula: Where K i K is the load-deformation coefficient of the steel ball and the inner ring, e is the load-deformation coefficient of the steel ball and outer ring.

7. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 1, characterized in that: In step S4, the vibration acceleration level L is calculated according to the radial vibration acceleration using the following formula, and the vibration magnitude of the four-point contact ball bearing under preload is evaluated by the vibration acceleration level L: Where, is the root mean square value of radial vibration acceleration, N is the number of steel balls, is the radial vibration acceleration of the bearing, A0 is the vibration standard reference value, which is taken as 9.81×10 -3 m / s 2 .

8. The vibration evaluation method of a four-point contact ball bearing under preload according to claim 1, characterized in that: Also includes: The radial vibration acceleration of the four-point contact ball bearing under different radial clearances is determined, and the vibration magnitude of the four-point contact ball bearing under preload is evaluated based on the radial vibration acceleration corresponding to different radial clearances.

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