Design calculation method for stress and hardness gradient of carburizing steel ball bearing, storage medium and electronic equipment

Abstract

The invention discloses a design and calculation method for the stress and hardness gradient of a carburizing steel ball bearing, a storage medium and electronic equipment. The design and calculation method comprises the following steps that the axial force, the radial force and the overturning moment borne by the carburizing steel ball bearing are determined; calculating the maximum contact stress of a rolling body and an outer ring in the carburizing steel ball bearing by utilizing a mechanical equilibrium equation; calculating the half width of ellipse contact; determining the maximum pressure of the center of the contact surface, and further solving stress values of the surface layer and the sub-surface layer; according to a fatigue limit and hardness conversion formula and the stress values, obtained in the fourth step, of the surface layer and the secondary surface layer, the Vickers hardness value needed for achieving the fatigue limit under the specific working condition when no residual stress exists is solved. The calculation method not only considers the influence of appearance parameters such as groove curvature, sphere diameter and sphere number in design, but also considers the influence of mechanical properties generated in manufacturing. And the requirement of fatigue life is met in the aspect of mechanical property design.

Description

Technical Field

[0001] The invention relates to the technical field of bearing design, and in particular to a design and calculation method for stress and hardness gradient of a carburized steel ball bearing, a storage medium and an electronic device. Background Art

[0002] At present, when designing non-standard ball bearings, we usually select the type, material, design appropriate parameters and processes according to the customer's working conditions and technical requirements to ensure the service life. Among the many failure modes, fatigue failure is the focus of R&D personnel.

[0003] The existing design method calculates fatigue life based on the ratio of equivalent load to rated load. There are no influencing parameters for residual stress and hardness gradient in the calculation parameters of rated load, but residual stress and hardness gradient will inevitably appear in the actual production process. The surface of carburized steel bearings has strong wear resistance and hardness, and the core is softer and can withstand certain impact loads. It is a very important type of bearing steel. The cost of the carburizing diffusion process is relatively high, so it is very important to design a suitable carburizing layer depth. The existing carburizing layer design mainly uses hardness as the objective function, and most of the process goals require that the depth of HV550 meet certain requirements, and there are no clear indicators for residual stress. Under light load conditions, the existing design methods can meet the design requirements (such as Figure 2 ), but once the heavy load exceeds a certain limit, in order to achieve a longer fatigue life, the hardness requirement of the lower part of the bearing surface will exceed HV1000 (such as Figure 3 ), which is far beyond the processing capacity. The numerical calculation method of the present invention comprehensively considers the residual stress and hardness gradient, and puts forward clear index requirements for these two aspects of the product. When the product has a certain residual compressive stress, the hardness requirement can be reduced without reducing the fatigue life, which has an important guiding role in the process. Summary of the invention

[0004] The purpose of the present invention is to provide a design calculation method, storage medium and electronic equipment for stress and hardness gradient of carburized steel ball bearings, which can solve the binary optimization problem of manufacturing cost and bearing fatigue life in existing bearing design.

[0005] The technical solution adopted by the present invention is:

[0006] A design and calculation method for stress and hardness gradient of a carburized steel ball bearing comprises the following steps:

[0007] Step 1: Determine the axial force, radial force and overturning moment of the carburized steel ball bearing according to the load conditions of the carburized steel ball bearing;

[0008] Step 2: Calculate the maximum contact stress between the rolling element and the outer ring of the carburized steel ball bearing using the mechanical equilibrium equation;

[0009] Step 3, calculating the ellipse contact half width according to the maximum contact stress between the rolling element and the outer ring calculated in step 2 and the principal curvature of the carburized steel ball bearing;

[0010] Step 4: Determine the maximum pressure at the center of the contact surface by using the maximum contact stress between the rolling element and the outer ring obtained in step 2 and the ellipse contact half width obtained in step 3, and then calculate the stress values ​​of the surface layer and the sub-surface layer;

[0011] Step 5: Based on the fatigue limit and hardness conversion formula combined with the stress values ​​of the surface and subsurface obtained in step 4, calculate the residual stress σ under specific working conditions. w1 When the Vickers hardness value HV required to reach the fatigue limit is

[0012] Step 6: According to the formula described in step 5, adjust the residual stress σ w1 and Vickers hardness value HV, so that the residual stress σ w1 and Vickers hardness HV are both within the range that can be achieved by existing processes.

[0013] Furthermore, in step 2, the maximum contact of a single rolling element is determined using the mechanical equation

[0014] The formula for stress is:

[0015]

[0016]

[0017] In the above formula, Q max1 It is the maximum contact stress between the rolling element and the outer ring under pure axial force; Q max2 It is the maximum contact stress between the rolling element and the outer ring under the condition of pure overturning moment; Q max3 is the maximum contact stress between the rolling element and the outer ring under pure radial force, α is the actual contact angle after loading, Z is the number of rolling elements, d m is the pitch diameter of the bearing, Fa is the axial force on the bearing, Fr ​​is the radial force on the bearing, and M is the overturning moment on the bearing.

[0018] Furthermore, in step 3, the calculation method of the ellipse contact half-width is:

[0019]

[0020] Where a and b are the major and minor axes of the elliptical contact, respectively; n a and n bis the coefficient related to the principal curvature difference function F(ρ) of the contact point, please refer to Appendix 1 for details; η is the comprehensive elastic constant; Q max It is the general term for the maximum contact stress between the rolling element and the outer ring under different conditions; Σρ is the principal curvature function, and the formula is:

[0021] Σρ=ρ 11 +ρ 12 +ρ 21 +ρ 22

[0022] Where:

[0023]

[0024] Where f e is the groove curvature radius coefficient, usually between 0.515 and 0.530; ρ 11 is the radius of curvature of the rolling element in the axial plane; ρ 12 is the radius of curvature of the rolling element in the radial plane; ρ 21 is the radius of curvature of the bearing outer ring in the axial plane; ρ 22 is the radius of curvature of the bearing outer ring in the radial plane; d m is the pitch diameter of the bearing, D w is the ball diameter of the rolling element.

[0025] Further, in step 4, the steps of determining the surface and sub-surface stresses of the carburized steel ball bearing are:

[0026] Step 41: Based on the maximum contact stress Q max , the major axis a and minor axis b of the elliptical contact are used to calculate the maximum pressure p0 at the center of the contact surface;

[0027] Step 42: Based on the Hertzian contact, the Hertzian stress field caused by the normal force loading is calculated from the maximum pressure at the center of the contact surface obtained in step 41 and the major and minor axes of the elliptical contact;

[0028] Step 43: Use the ball-on-disk test to simulate the lubrication condition of the bearing under operating conditions, combine the drag coefficient obtained from the test with the maximum pressure at the center of the contact surface obtained in step 42 and the major and minor axes of the elliptical contact, and calculate the Hertz stress field caused by the tangential friction force;

[0029] Step 44: Numerically add the Hertz stress field caused by the normal force and the Hertz stress field caused by the tangential friction force obtained in step 42 and step 43, and the sum thereof is the stress field when the bearing is working.

[0030] In the steps 5 and 6, the value of fatigue limit σw, residual stress σ w1 , contact stress σ w2, Vickers hardness HV satisfies the following relationship (ASTM8620 steel): The fatigue limit is generally a fixed value given by material testing, which has a linear relationship with hardness. The sum of the residual stress after bearing processing and the contact stress during operation cannot be greater than the fatigue limit. The contact stress σ has been calculated in step 4. w2 , then only the residual stress σ after bearing processing is needed w1 and hardness HV satisfy the above formula; when the residual stress σ w1 From the combinations of HV and hardness, find the most economical combination that is most likely to be achieved in processing.

[0031] A computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the device where the computer-readable storage medium is located executes the design and calculation method for stress and hardness gradient of a carburized steel ball bearing as described in any one of claims 1 to 5.

[0032] An electronic device comprises: a memory and a processor, wherein the memory stores a program that can be run on the processor, and when the processor executes the program, the design and calculation method for stress and hardness gradient of a carburized steel ball bearing as described in any one of claims 1 to 5 is implemented.

[0033] According to the load conditions of the carburized steel ball bearing, the axial force, radial force and overturning moment of the carburized steel ball bearing are determined; the maximum contact stress between the rolling element and the outer ring in the carburized steel ball bearing is calculated using the mechanical equilibrium equation; the elliptical contact half-width is calculated based on the maximum contact stress between the rolling element and the outer ring calculated in the previous step and the main curvature of the carburized steel ball bearing; the maximum contact stress between the rolling element and the outer ring and the elliptical contact half-width obtained by the above method are input into the formula described in the specific implementation method of this patent to determine the maximum pressure at the center of the contact surface, and then the stress values ​​of the surface and sub-surface are calculated; based on the fatigue limit and hardness conversion formula combined with the stress values ​​of the surface and sub-surface obtained in step four, the Vickers hardness value required to reach the fatigue limit under specific working conditions when there is no residual stress; the residual stress and Vickers hardness values ​​in the formula are adjusted so that the residual stress and Vickers hardness are within the range that can be achieved by the existing process. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 these drawings without paying creative work.

[0035] Figure 1 is a flow chart of the present invention;

[0036] Figure 2 This is a diagram of required hardness and machining hardness of a light-load bearing without considering the influence of residual stress in an embodiment of the present invention;

[0037] Figure 3 This is a diagram of the required hardness and processing hardness of the bearing under heavy load without considering the influence of residual stress in the embodiment of the present invention;

[0038] Figure 4 A diagram showing the required hardness and processing hardness of a bearing under consideration of the influence of residual stress in an embodiment of the present invention;

[0039] Figure 5 An experimental summary diagram of the drag coefficient used in the present invention to calculate the stress field caused by tangential friction;

[0040] Figure 6 Graph showing the stress from the surface layer to the sub-surface layer in an embodiment of the present invention. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] like Figure 1 , 2 As shown in 3, the present invention comprises the following steps:

[0043] Step 1: Determine the axial force, radial force and overturning moment of the bearing according to the load conditions of the bearing. Step 2: Calculate the maximum contact stress of a single rolling element using the mechanical equilibrium equation.

[0044]

[0045] In the above formulas, formula (1) is the case of bearing pure axial force; formula (2) is the case of bearing pure overturning moment; formula (3) is the case of bearing pure radial force, and α is the actual contact angle after loading.

[0046] Step 3: Calculate the elliptical contact half-width based on the contact stress and the groove type of the ball bearing.

[0047] The calculation method of the ellipse contact half-width is:

[0048]

[0049] Where a and b are the major and minor axes of the elliptical contact, respectively; n a and nb is the coefficient related to the principal curvature difference function F(ρ) of the contact point; Q is the contact load; η is the comprehensive elastic constant; Σρ is the principal curvature function.

[0050] Step 4: The maximum contact stress between the rolling element and the outer ring obtained in step 2 and the elliptical contact half-width obtained in step 3 are input into the model described in the present invention to determine the maximum pressure at the center of the contact surface, and then calculate the stress of the surface layer and the sub-surface layer.

[0051] The three-dimensional rolling-sliding stress field is mainly divided into two parts: one is the Hertz stress field caused by normal loading, and the other is the stress field caused by tangential friction. The calculation of the elliptical contact stress field is the superposition of the two partial stress fields.

[0052] The calculation range does not include the contact surface (i.e. z>0). The calculation formula is as follows:

[0053] σ x =σ xN +σ xF (4)

[0054] σ y =σ yN +σ yF (5)

[0055] σ z =σ zN +σ zF (6)

[0056] τ xy =τ xyN +τ xyF (7)

[0057] τ xz =τ xzN +τ xzF (8)

[0058] τ yz =τ yzN +τ yzF (9)

[0059] Where N represents the stress field caused by Normal Force, and F represents the stress field caused by Friction. x represents the normal stress in the x direction, τ xy Represents the shear force in the xy plane.

[0060] The calculation formula of the Hertzian contact stress field caused by the normal force is as follows:

[0061]

[0062] Where P0 is the maximum contact stress; v is Poisson's ratio, k = b / a, a is the half-width of the major axis of the contact ellipse, b is the half-width of the minor axis of the contact ellipse; x, y, z are the coordinates of each point under the subsurface. The calculation formula of the intermediate variable s is as follows:

[0063]

[0064] The calculation formula of L is as follows:

[0065] The expression of H is:

[0066] The expression of partial derivative is:

[0067]

[0068] The expression of k' is:

[0069] k' 2 =1-k 2 (26)

[0070] The values ​​of the auxiliary angles θ1 and θ2 in the partial derivatives are given by:

[0071]

[0072] The expressions of the intermediate variables n, C, N, and G are as follows:

[0073]

[0074] C=1+s 2 +N (30)

[0075] C=k 2 +s 2 +N (31)

[0076]

[0077] The expressions of the three elliptic integrals I1, I2, and I3 are as follows:

[0078]

[0079] The Hertz contact stress field caused by the normal force can be calculated by combining equations (4)-(36). The formula is derived from front to back, but when calculating the example, it is necessary to calculate s, H, L, n, C, N, G, I1, I2, I3 in sequence, and then bring these solved variables into equations (9) to (25) to calculate the partial derivatives, and then bring all the parameters into equations (10) to (15) to calculate the Hertz contact stress field caused by the normal force.

[0080] The calculation formula of the stress field caused by tangential friction is:

[0081]

[0082] The expression of partial derivative is:

[0083]

[0084] Where:

[0085]

[0086] The calculation method of the stress field caused by the tangential friction force is similar to that of the normal force, and both have the same intermediate variables. The difference is that the stress calculation formulas in the six directions are different in equations (10) to (15) and (37) to (42). In summary, the subsurface stress caused by the normal force and the tangential friction force can be obtained by combining equations (4) to (46).

[0087] Step 5: Calculate the hardness value required to reach the fatigue limit under specific working conditions based on the fatigue limit and hardness conversion formula.

[0088] Fatigue limit σ w The value of residual stress σ w1 , contact stress σ w2 , Vickers hardness HV satisfies the following relationship (ASTM8620 steel):

[0089] Step 6: Combine step 4 with step 5 to calculate the hardness and stress required from the surface to the subsurface. Now the contact stress σ is known. w2 , adjust the residual stress σ w1 and Vickers hardness HV, so that the two can meet the requirements of step 5 and meet the actual processing difficulty. The fatigue limit is generally a fixed value given by material testing, which has a linear relationship with the hardness; the sum of the residual stress after bearing processing and the contact stress during operation cannot be greater than the fatigue limit; the contact stress σ has been calculated in step 4 w2 , then only the residual stress σ after bearing processing is needed w1 and hardness HV satisfy the above formula; when the residual stress σ w1 From the combinations of HV and hardness, find the most economical combination that is most likely to be achieved in processing.

[0090] Compared with the existing design methods of carburized steel ball bearings in the industry, the present invention fully considers the influence of residual stress and hardness on the life of carburized steel ball bearings. The proposed dual objective function of residual stress and hardness is highly practical in the field of low speed and heavy load. It reduces the hardness requirement without reducing the life of the bearing, and can provide guidance for related production units.

[0091] The following is further explained with specific embodiments:

[0092] The example is a deep groove ball bearing 6209, which is subjected to a radial force of 3000 N. The following table gives the working conditions and load requirements of deep groove ball bearings:

[0093]

[0094]

[0095] Substitute the above parameters into formula (3) to calculate the maximum contact stress, and then substitute them into the formula in step 3 to calculate the major and minor axes of the contact ellipse:

[0096]

[0097] Using the above maximum contact stress, the major axis of the contact ellipse and the minor axis of the contact ellipse, the maximum pressure at the center of the contact surface can be calculated as 1178.45N according to step 41. Then, the stress of the surface layer and the sub-surface layer can be calculated by substituting the relevant formulas of step 42 and step 43. Figure 6 As shown,

[0098] The horizontal axis represents the rolling direction y of the rolling element, and the vertical axis represents the depth from the raceway surface to the sub-surface, such as Figure 6 It can be seen that the subsurface layer is the point with the maximum stress.

[0099] Final design requirements:

[0100] The final design requirements are as follows Figure 4 As shown, the surface stress is -392MPa, and the hardness at 0.3b below the surface reaches HV755, which meets the use requirements of "deep groove ball bearing 6209, bearing radial force 3000N".

[0101] A computer-readable storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the device where the computer-readable storage medium is located executes the above-mentioned design and calculation method for stress and hardness gradient of a carburized steel ball bearing. The computer program includes a computer program code, which may be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, a recording medium, a USB flash drive, a mobile hard disk, a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory and other memories.

[0102] An electronic device comprises: a memory and a processor, wherein the memory stores a program that can be run on the processor, and when the processor executes the program, the design and calculation method for stress and hardness gradient of a carburized steel ball bearing as described above is implemented.

[0103] The present invention utilizes the use conditions of the bearing and adopts the mechanical equilibrium equation to calculate the stress state of a single rolling element and a ferrule; utilizes the contact force between a single rolling element and a ball to obtain the contact stress and the half-width of the contact area; establishes Boussinesq and Cerruti potential functions, and solves the stress components at various positions from the surface to the subsurface according to the actual bearing load, elastohydrodynamic lubrication state analysis, and elastohydrodynamic drag force calculation; and selects a suitable hardness gradient and residual stress in accordance with the relationship between metal hardness and fatigue limit stress.

[0104] If the module / unit integrated in the electronic device described in this application is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present application implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware devices through a computer program. The computer program can be stored in a computer-readable storage medium, and when the computer program is executed by the processor, the steps of each of the above-mentioned method embodiments can be implemented.

[0105] Furthermore, the computer-readable storage medium may mainly include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function, etc.; the data storage area may store data created according to the use of the blockchain node, etc.

[0106] The computer-readable storage medium stores computer-readable instructions, which are executed by a processor in an electronic device to implement the design and calculation method for the stress and hardness gradient of a carburized steel ball bearing described in any of the above embodiments.

[0107] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are only illustrative, for example, the division of the modules is only a logical function division, and there may be other division methods in actual implementation.

[0108] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0109] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

[0110] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0111] Note that the above are only preferred embodiments of the present invention and the principles of the application technology. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention is described in more detail through the above embodiments, the present invention is not limited to the specific embodiments described herein, and may include more other effective embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. The design and calculation method of stress and hardness gradient of carburized steel ball bearings is characterized by: The steps include: Step 1: Determine the axial force, radial force and overturning moment of the carburized steel ball bearing according to the load conditions of the carburized steel ball bearing; Step 2: Calculate the maximum contact stress between the rolling element and the outer ring of the carburized steel ball bearing using the mechanical equilibrium equation; Step 3, calculating the ellipse contact half width according to the maximum contact stress between the rolling element and the outer ring calculated in step 2 and the principal curvature of the carburized steel ball bearing; Step 4: Determine the maximum pressure at the center of the contact surface by using the maximum contact stress between the rolling element and the outer ring obtained in step 2 and the ellipse contact half-width obtained in step 3, and then calculate the stress values ​​of the surface layer and the sub-surface layer; Step 5: Based on the fatigue limit and hardness conversion formula combined with the stress values ​​of the surface and subsurface obtained in step 4, calculate the residual stress σ under specific working conditions. w1 When the Vickers hardness value HV required to reach the fatigue limit is Step 6: According to the formula described in step 5, adjust the residual stress σ w1 and Vickers hardness value HV, so that the residual stress σ w1 and Vickers hardness HV are both within the range that can be achieved by existing processes.

2. The design and calculation method for stress and hardness gradient of carburized steel ball bearing according to claim 1 is characterized in that: In the step 2, the formula for determining the maximum contact stress of a single rolling element using the mechanical equation is: In the above formula, Q max1 It is the maximum contact stress between the rolling element and the outer ring under pure axial force; Q max2 It is the maximum contact stress between the rolling element and the outer ring under the condition of pure overturning moment; Q max3 is the maximum contact stress between the rolling element and the outer ring under pure radial force, α is the actual contact angle after loading, Z is the number of rolling elements, d m is the pitch diameter of the bearing, Fa is the axial force on the bearing, Fr ​​is the radial force on the bearing, and M is the overturning moment on the bearing.

3. The design and calculation method for stress and hardness gradient of carburized steel ball bearing according to claim 1 is characterized in that: In the step 3, the calculation method of the ellipse contact half-width is: Where a and b are the major and minor axes of the elliptical contact, respectively; n a and n b is the coefficient related to the principal curvature difference function F(ρ) of the contact point, please refer to Appendix 1 for details; η is the comprehensive elastic constant; Q max It is the general term for the maximum contact stress between the rolling element and the outer ring under different conditions; Σρ is the principal curvature function, and the formula is: Sr=r 11 +r 12 +r 21 +r 22 Where: Where f e is the groove curvature radius coefficient, usually between 0.515 and 0.530; ρ 11 is the radius of curvature of the rolling element in the axial plane; ρ 12 is the radius of curvature of the rolling element in the radial plane; ρ 21 is the radius of curvature of the bearing outer ring in the axial plane; ρ 22 is the radius of curvature of the bearing outer ring in the radial plane; d m is the pitch diameter of the bearing, D w is the ball diameter of the rolling element.

4. The design and calculation method for stress and hardness gradient of carburized steel ball bearing according to claim 1 is characterized in that: In the step 4, the step of determining the surface and sub-surface stresses of the carburized steel ball bearing is as follows: Step 41: Based on the maximum contact stress Q max , the major axis a and minor axis b of the elliptical contact are used to calculate the maximum pressure p0 at the center of the contact surface; Step 42: Based on the Hertzian contact, the Hertzian stress field caused by the normal force loading is calculated from the maximum pressure at the center of the contact surface obtained in step 41 and the major and minor axes of the elliptical contact; Step 43: Use the ball-on-disk test to simulate the lubrication condition of the bearing under operating conditions, combine the drag coefficient obtained from the test with the maximum pressure at the center of the contact surface obtained in step 42 and the major and minor axes of the elliptical contact, and calculate the Hertz stress field caused by the tangential friction force; Step 44: Numerically add the Hertz stress field caused by the normal force and the Hertz stress field caused by the tangential friction force obtained in step 42 and step 43, and the sum thereof is the stress field when the bearing is working.

5. The design and calculation method for stress and hardness gradient of carburized steel ball bearing according to claim 1 is characterized in that: In step 5, the value of fatigue limit σw, residual stress σ w1 , contact stress σ w2 , Vickers hardness HV satisfies the following relationship, taking carburized steel ball shaft as ASTM8620 steel as an example:

6. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the device where the computer-readable storage medium is located executes the design and calculation method for stress and hardness gradient of a carburized steel ball bearing as described in any one of claims 1 to 5.

7. An electronic device, characterized in that: include: A memory and a processor, wherein the memory stores a program that can be run on the processor, and when the processor executes the program, the design and calculation method for stress and hardness gradient of a carburized steel ball bearing as described in any one of claims 1-5 is implemented.

Images