Fatigue performance testing device and testing method of simulated angular contact ceramic ball bearing

Abstract

The application relates to the field of material service behavior evaluation, in particular to service behavior evaluation of ceramic balls in high-end bearings, and more specifically to a ceramic ball rolling contact fatigue performance testing device and testing method simulating the structure and lubrication of an angular contact ceramic ball bearing. The device comprises a fixing plate, a stand, a limiting plate, an upper thrust bearing, a lower thrust bearing, an upper conical ring base, a lower conical ring base, an upper conical ring, a lower conical ring, a retainer, a bearing steel rod and ceramic balls. According to the diameter size of the ceramic balls to be tested, the geometric relationship of the ball-rod contact is designed and calculated, the rotating speed and the contact stress are determined; according to the selected contact stress and the fatigue cycle of the trial test, the cut-off value of the constant cut-off test is determined; the rolling contact fatigue test is carried out on the ceramic balls to be tested, and the contact fatigue performance of the ceramic balls is evaluated. The application can evaluate ceramic balls of different diameter sizes without special sample preparation, so that the ceramic balls in actual bearings can be directly tested.

Description

Technical Field

[0001] This invention relates to the field of material service behavior evaluation, and particularly to the evaluation of the service behavior of ceramic balls in high-end bearings. Specifically, it relates to a testing device and method for testing the rolling contact fatigue performance of ceramic balls that simulates the structure and lubrication of angular contact ceramic ball bearings. Background Technology

[0002] Ceramic materials are a class of inorganic non-metallic materials. Compared with traditional bearing materials, they have advantages such as low density, high hardness, good wear resistance, high elastic modulus, insulation, and high temperature resistance. These advantages make them ideal materials for high-speed bearings. Currently, the most widely used type in high-speed machine tools is the angular contact ceramic ball bearing with ceramic rolling elements. Studies have shown that compared with bearing steel bearings, ceramic ball bearings using silicon nitride as the rolling element material can increase the limiting speed by about 25% to 35% and the fatigue life by about 3 times.

[0003] As a key component in angular contact ceramic ball bearings, the rolling contact fatigue performance of ceramic balls is a crucial factor determining the bearing's service performance and lifespan. Previously, the focus was primarily on the contact fatigue cycle life within the rolling contact fatigue performance of ceramic balls. However, with the development of high-end machine tools, the precision life of angular contact ceramic ball bearings has become more critical. Precision life refers to the bearing's actual service life, defined as the period during operation when vibration, frictional torque, and outer ring temperature rise exceed specified values. It is evident that precision life is closely related to changes in the surface morphology of the ceramic balls during rolling contact fatigue performance, such as the size, number, depth, and shape of surface micro-pits.

[0004] However, there is currently no mature and reliable method for evaluating the rolling contact fatigue performance of ceramic balls in angular contact ceramic ball bearings. The most common method is to directly conduct bearing bench tests. However, due to numerous influencing factors, bench tests can only barely assess the service performance of bearing components and cannot obtain information on the rolling contact fatigue performance of the ceramic ball rolling elements. In addition, there are some testing machines and methods specifically designed for the rolling contact fatigue performance of ceramic balls, but they have drawbacks such as only being able to assess the size of a single ceramic ball, and the lubrication conditions, friction pair, and cage materials cannot be changed according to the actual situation of angular contact ceramic ball bearings. Therefore, they cannot provide a reliable evaluation of the rolling contact fatigue performance of ceramic balls. Finally, existing evaluation methods do not comprehensively consider the impact of contact fatigue cycle life and the morphological changes of ceramic balls during rolling contact fatigue on precision life, making their evaluation of ceramic balls unsuitable for the development of modern high-end equipment.

[0005] Therefore, there is an urgent need to develop a method for evaluating the rolling contact fatigue performance of ceramic balls used in simulated angular contact ceramic ball bearings under typical structural and critical operating conditions. This method will provide a reliable testing tool for the development and optimized design of ceramic balls used in bearings, and promote the development of high-end equipment manufacturing. Summary of the Invention

[0006] The purpose of this invention is to provide a testing device and method for testing the rolling contact fatigue performance of ceramic balls that simulates the structure and lubrication of angular contact ceramic ball bearings. This method can evaluate the rolling contact fatigue performance of the ceramic balls under the typical structure and key operating conditions of angular contact ceramic ball bearings. This solves the problems of existing methods, which mostly rely on bench testing, resulting in high costs, numerous influencing factors, and inaccurate acquisition of rolling contact fatigue performance. At the same time, it also solves the problems of existing evaluation methods for ceramic balls, such as the uniform size of ceramic balls, significant differences in structure from angular contact ball bearings, inability to simulate lubrication conditions, and inability to eliminate the influence of friction pairs and cage materials.

[0007] The technical solution of this invention is:

[0008] A fatigue performance testing device simulating angular contact ceramic ball bearings includes a fixed plate, a column, a limiting plate, an upper thrust bearing, a lower thrust bearing, an upper tapered ring base, a lower tapered ring base, an upper tapered ring, a lower tapered ring, a cage, a bearing steel rod, and ceramic balls. The specific structure is as follows:

[0009] Two parallel columns are vertically mounted on a horizontal fixed plate. Bearing steel bars are vertically positioned between the two columns. The upper thrust bearing, upper conical ring base, upper conical ring, lower conical ring, lower conical ring base, and lower thrust bearing are sequentially fitted onto the bearing steel bars from top to bottom. The bearing steel bars are connected to the inner rings of the upper and lower thrust bearings, respectively. The inner surfaces of the upper and lower conical rings are annular conical surfaces and correspond vertically. The upper conical ring is fitted into the central hole of the upper conical ring base, and the lower conical ring is fitted into the central hole of the lower conical ring base. A retainer and ceramic balls are arranged between the rings. The three ceramic balls are evenly installed on the retainer. The upper conical ring is loaded downwards by its upper surface, and pressure is applied to the ceramic balls by its inner surface. The lower conical ring is loaded upwards by its lower surface, and pressure is applied to the ceramic balls by its inner surface. Three holes are opened on the horizontal limiting plate. The holes on both sides correspond to and match the columns, and the hole in the middle corresponds to and matches the bearing steel bar. After assembly, the limiting plate is fitted onto the two columns and the bearing steel bar, and slides with the columns and the bearing steel bar.

[0010] The fatigue performance testing device for the simulated angular contact ceramic ball bearing includes a bearing steel bar that simulates the inner ring of the angular contact ceramic ball bearing, an upper tapered ring and a lower tapered ring that simulate the outer ring of the angular contact ceramic ball bearing, and a cage that uses grease or lubricating oil to simulate the lubrication of an actual bearing, with the lubrication conditions being consistent with those of an actual bearing.

[0011] The fatigue performance testing device for the simulated angular contact ceramic ball bearing is similar to that for an actual angular contact ceramic ball bearing. During the test, the ceramic ball simultaneously makes rolling contact with the central bearing steel bar, upper and lower tapered rings, and cage under the lubrication of grease or lubricating oil.

[0012] A method for testing the fatigue performance of a simulated angular contact ceramic ball bearing includes the following steps:

[0013] a) Based on the diameter of the ceramic ball to be tested, design and calculate the geometric relationship of the ball-bar contact. Based on the above geometric relationship, select the appropriate combination of the outer ring of the tapered roller bearing and the diameter of the bearing steel bar. After the above parameters are determined, design the outer dimensions of the cage.

[0014] b) Determine the rotational speed and contact stress. These two parameters are mainly determined with reference to the service conditions of the bearing. Fix and select different levels of rotational speed and contact stress.

[0015] c) Determine the truncation value of the constant-number truncation test based on the selected contact stress and the fatigue cycles of the trial test;

[0016] d) Conduct rolling contact fatigue tests on the ceramic balls to be tested. The amount and type of lubricating grease used should be determined based on the actual bearing lubrication conditions.

[0017] e) Evaluation of the contact fatigue performance of ceramic balls: Combining the cycle data of rolling contact fatigue test and the micro morphology observation results of the ceramic ball surface after the test, the cycle is used as the characterization of fatigue life, and the micro-pits on the surface are used as the measure of precision life, so as to comprehensively evaluate the rolling contact fatigue performance of ceramic balls.

[0018] The fatigue performance testing method for simulated angular contact ceramic ball bearings involves conducting rolling contact fatigue tests on ceramic balls under simulated conditions of contact form, lubrication conditions, and materials of the rings and cage in actual angular contact ceramic ball bearings.

[0019] The fatigue performance testing method for the simulated angular contact ceramic ball bearing involves testing a ceramic ball with a variable outer diameter. Based on the outer diameter of the ceramic ball, appropriate tapered ring selection and machining, as well as the design of the friction bearing steel bar and cage dimensions, are performed. The friction bearing steel bar simulates the inner ring of the angular contact ceramic ball bearing, and its material and processing technology are consistent with those of the actual bearing inner ring.

[0020] The fatigue performance testing method for simulated angular contact ceramic ball bearings involves mounting the ceramic ball to be tested on a ball-bar type rolling contact fatigue testing machine to conduct a rolling contact fatigue test.

[0021] The fatigue performance testing method for simulated angular contact ceramic ball bearings obtains the rolling contact fatigue cycle life of the ceramic balls through a fixed-number truncated test.

[0022] The fatigue performance testing method for the simulated angular contact ceramic ball bearing involves conducting fatigue tests of different cycles and observing the surface morphology of the ceramic ball under a three-dimensional microscope after the test.

[0023] The fatigue performance test method for simulated angular contact ceramic ball bearings statistically analyzes the number, size, shape, and depth of micro-pits on the surface of the ceramic ball after rolling contact fatigue test, and uses these as a measure of the impact of the ceramic ball on the accuracy and life of the angular contact ceramic ball bearing.

[0024] The design concept of this invention is:

[0025] The structure of a ball-and-bar type rolling contact fatigue testing machine (three balls distributed at 120°, rolling in contact with the central friction bearing steel rod) is adopted. Based on the diameter of the ceramic ball to be tested, and according to the geometric relationship of three-point contact between the ceramic ball, the central friction bearing steel rod, and the upper and lower tapered rings, while maintaining a certain gap between the upper and lower tapered rings, the range of the outer diameter of the friction bearing steel rod sample, and the α, E, and C values ​​of the upper and lower tapered rings (using the outer ring of a tapered roller bearing) are obtained (see GB / T 297-2015). Based on the above structure, a suitable tapered roller bearing model is selected, and its outer ring is used as the upper and lower tapered rings, or it is machined (reducing the height of the outer ring without any machining on the inner surface) as the upper and lower tapered rings.

[0026] This invention is the first to consider the influence of the cage in the rolling contact fatigue performance test of ceramic balls. After the dimensions of the upper and lower conical rings and the bearing steel bar are designed, the external dimensions of the cage are designed so that the cage does not interfere with the upper and lower conical rings and the central bearing steel bar, while limiting the thickness of the pocket of the ceramic ball.

[0027] Based on the materials and processing technology of the rings and cages of the angular contact ceramic ball bearings used in the actual applications of the ceramic balls to be tested, the same materials and processing technology were selected to prepare the center-rubbing bearing steel rod specimens and cages. The grease or lubricating oil products and quantities used were also consistent with those of the actual bearings.

[0028] A ball-and-bar type rolling contact fatigue testing machine was used. Three ceramic balls were randomly selected from the ceramic balls to be tested. The prepared center friction bearing steel bar, upper and lower cone rings, cage and lubricating grease were used to carry out the rolling contact fatigue test.

[0029] The contact stress and rotational speed for rolling contact fatigue testing are determined based on the actual bearing parameters, allowing for tests to be conducted under different contact stress levels.

[0030] The fatigue cycle life of ceramic balls in rolling contact fatigue performance is tested by conducting fixed-number truncated tests, with no fewer than 12 tests performed. The truncated value is determined through exploratory testing. Vibration of the oil tank is measured using an accelerometer. When ceramic balls begin to peel off, the vibration value exceeds a threshold, and the testing machine automatically stops. The vibration threshold is typically set to 3 to 5 times the stable vibration value. After the test, the fatigue cycle data is processed according to the national standard GB10622-89 and the two-parameter Weibull distribution function.

[0031] Rolling contact fatigue tests were conducted on ceramic balls at different cycles through through-holes to test the surface morphology changes in rolling contact fatigue performance, which are closely related to accuracy and lifespan. After the tests, the three-dimensional surface morphology of the ceramic balls was observed at different magnifications, and the number, size, shape, and depth of micro-pits at different cycles were statistically analyzed.

[0032] By combining the surface morphology changes from fatigue cycle life and measurement accuracy life, the contact fatigue performance of ceramic balls is evaluated from two different dimensions.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] 1. Based on the size of the ceramic balls in the actual bearing to be tested, design the corresponding dimensions of the anti-friction bearing steel bar, upper and lower tapered rings, and cage, so as to enable testing of ceramic balls of different diameters.

[0035] 2. This invention proposes a method for testing the rolling contact fatigue performance of ceramic balls that more closely approximates the service conditions of ceramic balls in bearings. It allows for the direct selection of ceramic balls from actual bearings for testing, eliminating the need for special preparation of ceramic ball samples. It can evaluate ceramic balls of different diameters and eliminates the influence of sample preparation.

[0036] 3. The contact form, friction material, lubrication, and cage material of the ceramic ball rolling contact fatigue test of this invention can all be kept consistent with those of actual angular contact ceramic ball bearings.

[0037] 4. In addition to examining the fatigue spalling life of ceramic balls, this invention also uses the observation and analysis of micro-pits on the surface morphology of ceramic balls after fatigue testing as a measure of the precision life of ceramic balls, so as to meet the precision life requirements of high-end equipment bearings.

[0038] 5. This invention allows for multiple tests to be conducted on the same bearing steel bar, eliminating the influence of friction bearing materials when comparing and evaluating the rolling contact fatigue performance of ceramic balls. Attached Figure Description

[0039] Figure 1 An exploded view of the assembly of the core components for the contact fatigue test of the baseball bat.

[0040] Figure 2 This is an assembly view of the core components for the contact fatigue test of the baseball bat.

[0041] Figure 3 This is a geometric diagram showing the force relationship between the ceramic ball and the bearing steel rod during rolling contact.

[0042] Figure 4 Design diagram for the rolling contact fatigue geometry of ceramic balls of a specific diameter.

[0043] In the diagram, 1 is the fixing plate, 2 is the column, 3 is the limiting plate, 4 is the upper thrust bearing, 5 is the lower thrust bearing, 6 is the upper conical ring base, 7 is the lower conical ring base, 8 is the upper conical ring, 9 is the lower conical ring, 10 is the cage, 11 is the bearing steel bar, 12 is the ceramic ball, 13 is the pocket, 14 is the upper surface of the conical ring, and 15 is the inner surface of the conical ring. Detailed Implementation

[0044] The present invention will now be described in further detail with reference to the accompanying drawings.

[0045] like Figure 1 As shown, this invention proposes a ceramic ball bearing rolling contact fatigue performance testing device that simulates the structure and lubrication of angular contact ceramic ball bearings. As the core component of a ball-bar contact fatigue testing machine, it consists of 12 parts: a fixing plate 1, a column 2, a limiting plate 3, an upper thrust bearing 4, a lower thrust bearing 5, an upper conical ring base 6, a lower conical ring base 7, an upper conical ring 8, a lower conical ring 9, a cage 10, a bearing steel bar 11, and ceramic balls 12. The specific structure is as follows:

[0046] Two parallel columns 2 are vertically mounted on a horizontal fixed plate 1. Bearing steel rods 11 are vertically positioned between the two columns 2. An upper thrust bearing 4, an upper conical ring base 6, an upper conical ring 8, a lower conical ring 9, a lower conical ring base 7, and a lower thrust bearing 5 are sequentially mounted on the bearing steel rods 11 from top to bottom. The bearing steel rods 11 are connected to the inner rings of the upper thrust bearing 4 and the lower thrust bearing 5, respectively. The inner surfaces of the upper conical ring 8 and the lower conical ring 9 are annular conical surfaces and correspond vertically. The upper conical ring 8 is embedded in the central hole of the upper conical ring base 6, and the lower conical ring 9 is embedded in the central hole of the lower conical ring base 7. 8. A cage 10 and ceramic balls 12 are arranged between the lower tapered rings 9. The three ceramic balls 12 are evenly installed on the cage 10. The upper tapered ring 8 is loaded downwards through its upper surface, and the inner surface of the upper tapered ring 8 applies pressure to the ceramic balls 12. The lower tapered ring 9 is loaded upwards through its lower surface, and the inner surface of the lower tapered ring 9 applies pressure to the ceramic balls 12. Similar to actual angular contact ceramic ball bearings, during the test, the ceramic balls simultaneously make rolling contact with the central bearing steel bar (simulating the inner ring), the upper and lower tapered rings (simulating the outer ring), and the cage under the lubrication of grease or lubricating oil (simulating the lubrication of actual bearings).

[0047] Three holes are opened on the horizontal limiting plate 3. The holes on both sides correspond to and match the columns 2, and the hole in the middle corresponds to and matches the bearing steel rod 11. After assembly, the limiting plate 3 is sleeved on the two columns 2 and the bearing steel rod 11, and slides with the columns 2 and the bearing steel rod 11.

[0048] Figure 1 The image shown is an exploded view of the assembly drawing. The actual assembled result will look like this. Figure 2 As shown. Figures 1-2 As shown, during the experiment, the upper end of the bearing steel rod 11 is connected to the rotating spindle via a high-precision collet. The spindle is driven by a motor or electric spindle, and the bearing steel rod 11 rotates at high speed under the drive of the spindle. The rotation of the bearing steel rod 11 causes the ceramic ball 12 to rotate on its own axis and revolve around the bearing steel rod, thereby simulating the motion of the ceramic ball in an actual bearing.

[0049] Loading is achieved by the approach of the upper conical ring 8 and the lower conical ring 9. After the limiting plate 3 is fixed to the column 2 with bolts, the lower conical ring base 7 and the lower thrust bearing 5 rise linearly under the push of the loading spindle. The push of the loading spindle can be achieved by weights and levers. Ultimately, it forms as follows: Figure 3 The geometric and force relationships are shown.

[0050] Once the diameter of the ceramic ball 12 to be tested is determined, the dimensions of the corresponding bearing steel rod 11 and the conical ring (upper conical ring 8 or lower conical ring 9) are designed using drawing software, such as... Figure 4 As shown. Here, the diameter of the ceramic ball 12 to be tested is... For example, the ceramic ball 12 needs to be tangent to both the central bearing steel rod 11 and the inner surfaces 15 of the upper and lower conical rings. The outer diameters of the upper and lower conical rings need to match the inner diameter of the conical ring base (upper conical ring base 6 or lower conical ring base 7). Based on these requirements, for a diameter of... For the ceramic ball 12, a tapered roller bearing outer ring of model 32203 (GBT 297-2015) can be selected. The outer diameter of the bearing steel bar 11 is designed to be... Based on the distance of 1.15mm between the tangent point of the ceramic ball and the inner surface 15 of the conical ring and the center of the ceramic ball 12, and the distance of 13.29mm between the upper surface 14 of the conical ring and the center of the ceramic ball 12, and the contact angle α between the upper surface 14 of the conical ring and the inner surface 15 of the conical ring, it can be concluded that in order to ensure that there is a certain gap between the upper conical ring 8 and the lower conical ring 9, the height of the outer ring of 32203 needs to be reduced by 1.2mm by a surface grinder.

[0051] After the dimensions of the upper conical ring 8, lower conical ring 9, and bearing steel rod 11 are designed, the external dimensions of the cage 10 are designed. The cage 10 is similar in shape to a section of circular tube, with three pockets 13 at 120° intervals around its circumference for placing ceramic balls 12. The dimensions of the cage 10 are designed to avoid interference with the upper conical ring 8, lower conical ring 9, and the central rubbing bearing steel rod 11, while also having a certain wall thickness to support the rotation of the ceramic balls 12.

[0052] Based on the materials and processing technology of the rings and cages of the angular contact ceramic ball bearings used in the actual applications of the ceramic balls to be tested, the same materials and processing technology were selected to prepare the center-rubbing bearing steel rod specimens and cages. The lubricating oil or grease products and quantities used were also consistent with those of the actual bearings.

[0053] The fatigue cycle life of ceramic balls in rolling contact fatigue performance was tested by conducting a fixed-number truncated test. The truncated value was determined through exploratory experiments. The vibration of the oil box (located outside the lower conical ring base 7, tightly fitted with it) was measured using an accelerometer. When ceramic balls 12 began to peel off, the vibration value exceeded the threshold, and the testing machine automatically stopped. The vibration threshold was typically set to 3 to 5 times the stable vibration value. Referring to GB 10622-89 "Metallic Materials - Rolling Contact Fatigue Test Method", the fatigue cycle data was processed using the Weibull distribution to provide the L10 and L50 lives and the b value.

[0054] Note: When the ceramic ball is of very high quality, the bearing steel bar will usually be the first to peel off in the ball-bar contact fatigue test. In this case, the fatigue cycle life cannot be used to evaluate the rolling contact fatigue performance of the ceramic ball.

[0055] The precision life characterization of the rolling contact fatigue performance of ceramic balls was measured by conducting rolling contact fatigue tests of different cycles on the same bearing steel bar. After different cycles of testing, the surface three-dimensional morphology of the ceramic balls was observed at different magnifications using Keyence morphology microscopes and white light interferometers, and the number, size, shape, and depth of micro-pits under different cycles were statistically analyzed.

[0056] By combining fatigue cycle life and precision life measurement results, the contact fatigue performance of ceramic balls is evaluated from two different dimensions.

[0057] Example 1:

[0058] This embodiment uses the testing method of the present invention to conduct rolling contact fatigue tests on Si3N4 ceramic balls from different manufacturers to evaluate the performance of ceramic balls from different manufacturers. The results are shown in Table 1. Note that, as a preliminary verification of the testing method of the present invention, only one test was conducted for each type of ceramic ball in this embodiment.

[0059] As shown in the table, the method of the present invention can reproduce the rolling contact fatigue spalling of ceramic balls, and the number of rolling contact fatigue spalling cycles of ceramic balls from different manufacturers varies significantly, ranging from 10 to the power of 4 to the power of 7. This initially shows that the method of the present invention can effectively evaluate the performance of ceramic balls for bearings.

[0060] Table 1 shows the rolling contact fatigue tests of ceramic balls conducted using the test method of this invention.

[0061]

[0062] The results show that this invention not only uses fatigue life, which is commonly used to evaluate rolling contact fatigue performance, as an evaluation index, but also, based on the actual bearing usage, uses micro-pits in the surface morphology of the ceramic ball after the test as an evaluation index for precision life.

Claims

1. A method for testing the fatigue performance of a simulated angular contact ceramic ball bearing, characterized in that, The device used includes a fixed plate, column, limiting plate, upper thrust bearing, lower thrust bearing, upper conical ring base, lower conical ring base, upper conical ring, lower conical ring, cage, bearing steel rod, and ceramic ball. The specific structure is as follows: Two parallel columns are vertically mounted on a horizontal fixed plate. Bearing steel bars are vertically positioned between the two columns. The upper thrust bearing, upper conical ring base, upper conical ring, lower conical ring, lower conical ring base, and lower thrust bearing are sequentially fitted onto the bearing steel bars from top to bottom. The bearing steel bars are connected to the inner rings of the upper and lower thrust bearings, respectively. The inner surfaces of the upper and lower conical rings are annular conical surfaces and correspond vertically. The upper conical ring is fitted into the central hole of the upper conical ring base, and the lower conical ring is fitted into the central hole of the lower conical ring base. A retainer and ceramic balls are arranged between the rings. The three ceramic balls are evenly installed on the retainer. The upper conical ring is loaded downwards by its upper surface, and pressure is applied to the ceramic balls by its inner surface. The lower conical ring is loaded upwards by its lower surface, and pressure is applied to the ceramic balls by its inner surface. Three holes are opened on the horizontal limiting plate. The holes on both sides correspond to and match the columns, and the hole in the middle corresponds to and matches the bearing steel bar. After assembly, the limiting plate is sleeved on the two columns and the bearing steel bar, and slides in fit with the columns and the bearing steel bar. The method includes the following steps: a) Based on the diameter of the ceramic ball to be tested, design and calculate the geometric relationship of the ball-bar contact. Based on the above geometric relationship, select the appropriate combination of the outer ring of the tapered roller bearing and the diameter of the bearing steel bar. After the above parameters are determined, design the outer dimensions of the cage. b) Determine the rotational speed and contact stress. These two parameters are mainly determined with reference to the service conditions of the bearing. Fix and select different levels of rotational speed and contact stress. c) Determine the truncation value of the constant-number truncation test based on the selected contact stress and the fatigue cycles of the trial test; d) Conduct rolling contact fatigue tests on the ceramic balls to be tested. The amount and type of lubricating grease used should be determined based on the actual bearing lubrication conditions. e) Evaluation of the contact fatigue performance of ceramic balls: Combining the cycle data of rolling contact fatigue test and the micro morphology observation results of the ceramic ball surface after the test, the cycle is used as the characterization of fatigue life, and the micro-pits on the surface are used as the measure of precision life, and the rolling contact fatigue performance of ceramic balls is comprehensively evaluated.

2. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, Rolling contact fatigue tests were conducted on ceramic balls under simulated conditions of contact form, lubrication conditions, and materials of rings and cages in actual angular contact ceramic ball bearings.

3. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, The outer diameter of the ceramic ball is variable. Based on the outer diameter of the ceramic ball, the corresponding tapered ring is selected and processed, and the outer dimensions of the friction bearing steel bar and cage are designed. The friction bearing steel bar simulates the inner ring of the angular contact ceramic ball bearing, and its material and processing technology are consistent with those of the actual bearing inner ring.

4. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, The ceramic ball to be tested is mounted on a ball-and-bar type rolling contact fatigue testing machine for rolling contact fatigue testing.

5. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, The rolling contact fatigue cycle life of the ceramic ball was obtained through a constant-number truncation test.

6. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, Fatigue tests were conducted for different cycles, and the surface morphology of the ceramic balls after the tests was observed under a three-dimensional microscope.

7. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, The number, size, shape, and depth of micro-pits on the surface of ceramic balls after rolling contact fatigue tests were statistically analyzed and used as a measure of the impact of ceramic balls on the accuracy and life of angular contact ceramic ball bearings.

8. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, The bearing steel bar simulates the inner ring of the angular contact ceramic ball bearing, while the upper and lower tapered rings simulate the outer ring of the angular contact ceramic ball bearing. The cage uses grease or oil to simulate the lubrication of an actual bearing, and the lubrication conditions are consistent with those of an actual bearing.

9. The fatigue performance testing method for simulated angular contact ceramic ball bearings according to claim 1, characterized in that, During the test, the ceramic ball simultaneously rolls into contact with the central bearing steel bar, upper and lower tapered rings, and cage under the lubrication of grease or lubricating oil.

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