Device and method for measuring axial play of large-size three-point angular contact ball bearing
By designing a dynamic measuring device and a flexible loading method, the problem of misalignment between the inner and outer rings in the axial clearance measurement of large three-point angular contact ball bearings was solved, achieving high-precision axial clearance detection with an accuracy within 0.006 mm.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- AVIC HARBIN BEARING CO LTD
- Filing Date
- 2023-04-07
- Publication Date
- 2026-05-19
AI Technical Summary
Existing static measurement methods for axial clearance of three-point angular contact ball bearings cannot avoid measurement distortion caused by relative positional offset and angular deviation between the inner and outer rings, especially for large bearings where there is a lack of effective measurement devices and methods.
A device for measuring the axial clearance of a large-size three-point angular contact ball bearing was designed. It employs a dynamic measurement method and a flexible loading method. The relative position of the inner and outer rings is adjusted by a flexible loading disk, and the inner and outer rings are made into close contact by utilizing the steel ball climbing principle. The axial clearance of the bearing is measured by a digital displacement sensor.
It enables rapid, accurate, and convenient axial clearance detection of large three-point angular contact ball bearings, with a detection accuracy of less than 0.006 mm, avoiding positional offset and angular deviation errors during the measurement process.
Smart Images
Figure CN116448041B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of bearing axial clearance detection, specifically to a device and method for measuring the axial clearance of a large-size three-point angular contact ball bearing. Background Technology
[0002] The X196 model, a commonly used axial clearance measuring instrument in the industry, is applicable to bearings with an outer diameter maximum of 300mm. Its measurement principle involves clamping the outer ring of the bearing under test with a clamping device, and then measuring the displacement of the inner ring between two extreme axial positions to obtain the corresponding axial clearance. However, there is currently no suitable measuring instrument for large three-point angular contact ball bearings with an outer diameter of up to 600mm. Chinese utility model patent CN205808323U, published on December 14, 2016, discloses a fixture for measuring the axial clearance of four-point angular contact ball bearings with separate inner and outer rings. However, this fixture uses a static measurement method, which cannot avoid the problem of bearing clearance measurement distortion caused by relative positional misalignment of the rings and angular deviation during the bearing measurement process. Summary of the Invention
[0003] The purpose of this invention is to solve the problem that existing static measurement methods for axial clearance of three-point angular contact ball bearings cannot avoid the bearing clearance measurement distortion caused by the relative positional offset between the inner and outer rings and angular deviation during the bearing measurement process, and to provide a device and method for measuring the axial clearance of large-size three-point angular contact ball bearings.
[0004] The technical solution of this invention is:
[0005] A large-size three-point angular contact ball bearing axial clearance measuring device includes a left measuring device 1, a bearing under test 2, a gland 3, a bearing inner ring fixture 4, a hollow spindle rotating device 5, a right measuring device 6, a right loading device 7, a spindle bearing housing 8, a spindle loading device 9, a spindle bearing 10, a frame 11, a left loading device 12, a flexible loading disk 13, a base 14, and a bearing outer ring fixture 15. A frame circular hole is formed in the middle of the upper surface of the frame 11, and a spindle bearing housing 8 is installed at the frame circular hole. Two spindle bearings 10 are installed inside the spindle bearing housing 8. The hollow spindle rotating device 5 passes vertically from top to bottom through the spindle bearing housing 8 and the frame circular hole. The middle of the hollow spindle rotating device 5 is connected to the spindle via the spindle bearings 10. The bearing housing 8 is rotatably connected. The lower part of the hollow spindle rotating device 5 is connected to the loading end of the spindle loading device 9. The upper part of the hollow spindle rotating device 5 is fitted with the bearing inner ring fixture 4. The left loading device 12 and the right loading device 7 are vertically and symmetrically arranged on the left and right sides of the spindle bearing housing 8. The flexible loading disk 13 is fitted on the spindle bearing housing 8. The lower surface of the flexible loading disk 13 is connected to the loading ends of the left loading device 12 and the right loading device 7 respectively. The base 14 is installed on the flexible loading disk 13. The bearing outer ring fixture 15 is installed on the base 14. The left measuring device 1 and the right measuring device 6 are installed on the left and right sides of the upper surface of the bearing outer ring fixture 15 respectively. The outer ring of the bearing 2 to be measured is installed on the bearing outer ring fixture 15, and the inner ring of the bearing 2 to be measured is installed on the bearing inner ring fixture 4.
[0006] Furthermore, the inner ring tooling 4 of the bearing has an annular groove along the circumferential direction that matches the outer ring of the bearing 2 being tested.
[0007] Furthermore, the outer side of the bearing inner ring fixture 4 is machined with a right-angled annular notch along the circumferential direction, which matches the inner ring of the bearing 2 being tested.
[0008] Furthermore, the hollow spindle rotating device 5 includes a spindle body and a servo motor. The lower end of the spindle body is connected to the rotor of the servo motor via a coupling, and the servo motor is connected to the loading end of the spindle loading device 9.
[0009] Furthermore, the main spindle body is a stepped shaft, with the first, second, third, fourth, and fifth shaft segments sequentially arranged from the input end to the output end. A shoulder A is formed between the first and second shaft segments, and the shoulder A abuts against the upper surface of the inner ring of the upper main spindle bearing 10. A shoulder B is formed between the second and third shaft segments. The lower part of the bearing inner ring fixture 4 is located at the third shaft segment, and the lower surface of the bearing inner ring fixture 4 abuts against the shoulder B. The upper part of the bearing inner ring fixture 4 and the bearing 2 under test are located at the fourth shaft segment. A shoulder C is formed between the fourth and fifth shaft segments. The pressure cap 3 is located at the fifth shaft segment. The fifth shaft segment is machined with external threads, and the center hole of the pressure cap 3 is machined with internal threads. The pressure cap 3 is threadedly connected to the fifth shaft segment.
[0010] Furthermore, the pressure cap 3 is a circular plate structure, and the diameter of the pressure cap 3 is smaller than the outer diameter of the inner ring of the bearing 2 being tested, while the inner diameter of the inner ring of the bearing 2 being tested is smaller than the diameter of the pressure cap 3.
[0011] Furthermore, the flexible loading disk 13 includes an upper disk body, a middle flexible sleeve, and a lower disk body. The upper disk body, the middle flexible sleeve, and the lower disk body are sequentially sleeved on the outside of the main spindle bearing seat 8 from top to bottom. The upper disk body has an upper circular through hole machined in the center, and the lower disk body has a lower circular through hole in the center. The circular through hole of the lower disk body can slide and fit with the outer wall of the main spindle bearing seat 8. The middle flexible sleeve is made of rubber material, and both the upper and lower end faces of the middle flexible sleeve are machined with annular grooves. The lower annular outer edge of the upper disk body is inserted into the upper annular groove of the middle flexible sleeve, and the upper annular outer edge of the lower disk body is inserted into the lower annular groove of the middle flexible sleeve.
[0012] Furthermore, the base 14 is a circular plate structure with a circular hole in the center. A base sleeve is integrally formed with the base 14 and arranged coaxially at the circular hole. The lower end of the base sleeve is inserted into the circular through hole of the upper part of the flexible loading disk 13.
[0013] Furthermore, the main spindle bearing housing 8 is a hollow cylindrical structure with openings at both ends. The inner cylindrical surface at the lower end of the main spindle bearing housing 8 is provided with a first annular boss in the radial direction. The upper surface of the first annular boss abuts against the lower end face of the outer ring of the lower bearing. The outer cylindrical surface at the lower end of the main spindle bearing housing 8 is provided with a second annular boss in the radial direction. The lower surface of the second annular boss abuts against the upper surface of the frame 11.
[0014] A measurement method for the axial clearance measuring device of a large-size three-point angular contact ball bearing, based on any one of the specific embodiments one to nine, wherein the axial clearance measurement method for the large-size three-point angular contact ball bearing is implemented through the following steps.
[0015] Step 1: Start the control system and set the relevant parameters of the left loading device 12, right loading device 7, hollow spindle rotation device 5 and spindle loading device 9 as required;
[0016] Step 2: Using the inner ring fixture 4, the cover 3, and the outer ring fixture 15, the bearing 2 to be tested is fixed on the hollow spindle rotating device 5 to form the inner ring rotating mechanism. It is fixed on the frame 11 by the spindle bearing 10 and achieves stable rotation. The spindle loading device 9 is started, and a vertical downward pulling force is applied to the inner ring rotating mechanism to prevent the inner ring rotating mechanism from displacing in the vertical direction.
[0017] Step 3: The hollow spindle rotating device 5 is started, and the test bearing 2 is pressed by the hollow spindle rotating device 5 and the pressure cover 3; then the left loading device 12 and the right loading device 7 are started, and vertical upward and vertical downward forces are applied to the outer ring of the test bearing 2 through the left loading device 12 and the right loading device 7 to make it reach the upper and lower measurement limit positions; the displacement of the outer ring of the test bearing 2 between the two limit positions is measured by the left measuring device 1 and the right measuring device 6, and the average value of the two displacements is the axial clearance of the bearing.
[0018] Step 4: After the measurement is completed, turn off the left loading device 12, the right loading device 7, the hollow spindle rotation device 5, and the spindle loading device 9. The test is now over.
[0019] Compared with the prior art, the present invention has the following advantages:
[0020] 1. This invention addresses the challenge of detecting the clearance of large three-point angular contact ball bearings. Based on the principle of bearing clearance detection, it develops a fast, accurate, and convenient dynamic measurement device for bearing axial clearance. The device can accurately detect the axial clearance of large-size three-point angular contact ball bearings with a repeatability accuracy of less than 0.006 mm.
[0021] 2. This invention employs a dynamic measurement method and a flexible loading method. Specifically, the flexible loading disk 13 consists of two identical circular disk-shaped rigid structures bonded together by a ring-shaped high-elasticity rubber. When the base 14 and the hollow spindle rotating device 5 cannot maintain a perfectly perpendicular state, an angular misalignment may occur between the inner and outer rings of the bearing under test 2. The high-elasticity rubber can automatically adjust the height of both sides of the flexible loading disk 13 to eliminate this angular misalignment, ensuring close contact between the inner and outer rings of the bearing under test 2 via steel balls. Furthermore, by dynamically rotating the inner ring of the bearing under test 2, the principle of steel ball climbing is used to achieve a parallel state between the inner and outer rings, ensuring the accuracy of the bearing axial clearance measurement. Attached Figure Description
[0022] Figure 1 This is a schematic diagram of the structure of the large-size three-point angular contact ball bearing axial clearance measuring device of the present invention.
[0023] In the diagram: 1-Left measuring device; 2-Bearing under test; 3-Gland; 4-Bearing inner ring fixture; 5-Hollow spindle rotation device; 6-Right measuring device; 7-Right loading device; 8-Spindle bearing housing; 9-Spindle loading device; 10-Spindle bearing; 11-Frame; 12-Left loading device; 13-Flexible loading disk; 14-Base; 15-Bearing outer ring fixture. Detailed Implementation
[0024] Specific implementation method one: Combining Figure 1This embodiment describes a large-size three-point angular contact ball bearing axial clearance measuring device, which includes a left measuring device 1, a bearing under test 2, a pressure cap 3, a bearing inner ring fixture 4, a hollow spindle rotating device 5, a right measuring device 6, a right loading device 7, a spindle bearing housing 8, a spindle loading device 9, a spindle bearing 10, a frame 11, a left loading device 12, a flexible loading disk 13, a base 14, and a bearing outer ring fixture 15. A frame circular hole is formed in the middle of the upper surface of the frame 11, and a spindle bearing housing 8 is installed at the frame circular hole. Two spindle bearings 10 are installed inside the spindle bearing housing 8. The hollow spindle rotating device 5 passes through the spindle bearing housing 8 and the frame circular hole in a vertical direction from top to bottom. The middle part of the hollow spindle rotating device 5 is rotatably connected to the spindle bearing housing 8 through the spindle bearings 10. The lower part of the rotating device 5 is connected to the loading end of the spindle loading device 9. The upper part of the hollow spindle rotating device 5 is fitted with a bearing inner ring fixture 4. The left loading device 12 and the right loading device 7 are vertically and symmetrically arranged on the left and right sides of the spindle bearing seat 8. The flexible loading disk 13 is fitted on the spindle bearing seat 8. The lower surface of the flexible loading disk 13 is connected to the loading ends of the left loading device 12 and the right loading device 7, respectively. A base 14 is installed on the flexible loading disk 13. A bearing outer ring fixture 15 is installed on the base 14. The left measuring device 1 and the right measuring device 6 are installed on the left and right sides of the upper surface of the bearing outer ring fixture 15, respectively. The outer ring of the bearing 2 to be measured is installed on the bearing outer ring fixture 15, and the inner ring of the bearing 2 to be measured is installed on the bearing inner ring fixture 4. The left loading device 12, the right loading device 7, the hollow spindle rotating device 5, and the spindle loading device 9 are connected to the control system.
[0025] In this embodiment, the tested bearing 2, pressure cap 3, bearing inner ring tooling 4, hollow spindle rotating device 5, spindle bearing seat 8, spindle loading device 9, spindle bearing 10, frame circular hole of frame 11, flexible loading disk 13, base 14 and bearing outer ring tooling 15 are all coaxially arranged.
[0026] In this embodiment, the spindle loading device 9, the left loading device 12, and the right loading device 7 are all 1086 loading devices manufactured by Dalian Kehui Bearing Instrument Co., Ltd.
[0027] In this embodiment, both the left measuring device 1 and the right measuring device 6 are digital displacement sensors.
[0028] Specific Implementation Method Two: Combining Figure 1In this embodiment, the inner ring fixture 4 has an annular groove machined along the circumferential direction on its inner side to match the outer ring of the bearing 2 under test. With this configuration, the outer ring of the bearing 2 under test is installed within the annular groove on the inner side of the bearing inner ring fixture 4. To facilitate the assembly of the outer ring of the bearing 2 under test, the bearing inner ring fixture 4 can be designed as a split structure. After the outer ring of the bearing 2 under test is installed, the split structure is connected using screws or other connecting elements. Other components and connection relationships are the same as in specific embodiment one.
[0029] Specific implementation method three: Combining Figure 1 In this embodiment, the outer side of the bearing inner ring fixture 4 is machined with a right-angled annular notch along the circumferential direction, matching the inner ring of the bearing 2 under test. With this configuration, the inner ring of the bearing 2 under test is installed at the annular notch on the outer side of the bearing inner ring fixture 4. The pressure cap 3 is threadedly connected to the upper end of the hollow spindle rotating device 5. The pressure cap 3 and the bearing inner ring fixture 4 work together to press and fix the bearing 2 under test. Other components and connections are the same as in specific embodiments one or two.
[0030] Specific implementation method four: Combination Figure 1 This embodiment describes a hollow spindle rotating device 5 comprising a spindle body and a servo motor. The lower end of the spindle body is connected to the rotor of the servo motor via a coupling, and the servo motor is connected to the loading end of the spindle loading device 9. With this configuration, the tested bearing 2 and the bearing inner ring fixture 4 are integrally mounted on the hollow spindle rotating device 5. The servo motor drives the hollow spindle rotating device 5 to rotate, and the spindle loading device 9 applies a vertically downward pulling force to the hollow spindle rotating device 5, ensuring that the hollow spindle rotating device 5 does not displace upwards when the left loading device 12 and the right loading device 7 simultaneously push the bearing outer ring upwards. Other components and connections are the same as in specific embodiments one, two, or three.
[0031] Specific Implementation Method Five: Combining Figure 1 In this embodiment, the main shaft body is a stepped shaft. From the input end to the output end, the stepped shaft consists of a first shaft segment, a second shaft segment, a third shaft segment, a fourth shaft segment, and a fifth shaft segment. A shoulder A is formed between the first and second shaft segments, and this shoulder A abuts against the upper surface of the inner ring of the upper main shaft bearing 10. A shoulder B is formed between the second and third shaft segments. The lower part of the bearing inner ring fixture 4 is located at the third shaft segment, and its lower surface abuts against shoulder B. The upper part of the bearing inner ring fixture 4 and the tested bearing 2 are located at the fourth shaft segment. A shoulder C is formed between the fourth and fifth shaft segments. A pressure cap 3 is located at the fifth shaft segment. The fifth shaft segment is machined with external threads, and the center hole of the pressure cap 3 is machined with internal threads. The pressure cap 3 is threadedly connected to the fifth shaft segment. Other components and connections are the same as in specific embodiments one, two, three, or four.
[0032] Specific Implementation Method Six: Combination Figure 1 In this embodiment, the pressure cap 3 is a circular plate structure. The diameter of the pressure cap 3 is smaller than the outer diameter of the inner ring of the bearing 2 being tested, and the inner diameter of the inner ring of the bearing 2 being tested is smaller than the diameter of the pressure cap 3. This configuration ensures that the pressure cap 3 can press the inner ring of the bearing 2 being tested, and together with the bearing inner ring tool 4, it can press the inner ring of the bearing 2 being tested tightly. Other components and connections are the same as in specific embodiments one, two, three, four, or five.
[0033] Specific implementation method seven: Combining Figure 1 This embodiment describes a flexible loading disk 13 comprising an upper disk body, a middle flexible sleeve, and a lower disk body. The upper disk body, the middle flexible sleeve, and the lower disk body are sequentially fitted onto the outside of the main spindle bearing seat 8 from top to bottom. The upper disk body has an upper circular through hole machined at its center, and the lower disk body has a lower circular through hole at its center. The circular through hole of the lower disk body is slidably fitted with the outer wall of the main spindle bearing seat 8. The middle flexible sleeve is made of rubber material, and both the upper and lower end faces of the middle flexible sleeve are machined with annular grooves. The lower annular outer edge of the upper disk body is inserted into the upper annular groove of the middle flexible sleeve, and the upper annular outer edge of the lower disk body is inserted into the lower annular groove of the middle flexible sleeve. With this configuration, the left loading device 12 and the right loading device 7 simultaneously push the outer ring upward. When the base 14 and the hollow spindle rotating device 5 cannot be guaranteed to be completely perpendicular, an angular misalignment will occur between the inner and outer rings of the bearing. At this time, the high-elastic rubber can automatically adjust the height of both sides of the flexible loading disk 13 to eliminate the angular misalignment between the inner and outer rings, so that the left and right sides of the inner and outer rings of the bearing achieve tight contact through the steel balls. Other components and connections are the same as in specific embodiments one, two, three, four, five, or six.
[0034] Specific implementation method eight: Combination Figure 1 In this embodiment, the base 14 is a circular plate structure with a circular hole at its center. A base sleeve, integrally formed with and coaxially arranged with the base 14, is located at the circular hole. The lower end of the base sleeve is inserted into the circular through hole in the upper part of the flexible loading disk 13. Other components and connections are the same as in specific embodiments one, two, three, four, five, six, or seven.
[0035] Specific Implementation Method Nine: Combining Figure 1 In this embodiment, the spindle bearing housing 8 is a hollow cylindrical structure open at both ends. A first annular boss is radially provided on the inner cylindrical surface at the lower end of the spindle bearing housing 8. The upper surface of the first annular boss abuts against the lower end face of the outer ring of the lower bearing. A second annular boss is radially provided on the outer cylindrical surface at the lower end of the spindle bearing housing 8. The lower surface of the second annular boss abuts against the upper surface of the frame 11. Other components and connections are the same as in specific embodiments one, two, three, four, five, six, seven, or eight.
[0036] Specific Implementation Method Ten: Combining Figure 1 This embodiment describes a measurement method for the axial clearance of a large-size three-point angular contact ball bearing based on any one of embodiments one through nine. The method for measuring the axial clearance of the large-size three-point angular contact ball bearing is implemented through the following steps:
[0037] Step 1: Start the control system and set the relevant parameters of the left loading device 12, right loading device 7, hollow spindle rotation device 5 and spindle loading device 9 as required;
[0038] Step 2: Using the inner ring fixture 4, the cover 3, and the outer ring fixture 15, the bearing 2 to be tested is fixed on the hollow spindle rotating device 5 to form the inner ring rotating mechanism. It is fixed on the frame 11 by the spindle bearing 10 and achieves stable rotation. The spindle loading device 9 is started, and a vertical downward pulling force is applied to the inner ring rotating mechanism to prevent the inner ring rotating mechanism from displacing in the vertical direction.
[0039] Step 3: The hollow spindle rotating device 5 is started, and the test bearing 2 is pressed by the hollow spindle rotating device 5 and the pressure cover 3; then the left loading device 12 and the right loading device 7 are started, and vertical upward and vertical downward forces are applied to the outer ring of the test bearing 2 through the left loading device 12 and the right loading device 7 to make it reach the upper and lower measurement limit positions; the displacement of the outer ring of the test bearing 2 between the two limit positions is measured by the left measuring device 1 and the right measuring device 6, and the average value of the two displacements is the axial clearance of the bearing.
[0040] Step 4: After the measurement is completed, turn off the left loading device 12, the right loading device 7, the hollow spindle rotation device 5, and the spindle loading device 9. The test is now complete. Other components and connections are the same as in embodiments one, two, three, four, five, six, seven, eight, or nine.
[0041] Working principle
[0042] Combination Figure 1 The working principle of the large-size three-point angular contact ball bearing axial clearance measuring device of the present invention is explained as follows:
[0043] This invention employs an inner bearing ring fixture 4, a pressure cap 3, and an outer bearing ring fixture 15 to fix the bearing 2 under test onto a hollow spindle rotating device 5, forming an integral inner ring rotating mechanism. The spindle bearing 10 is fixed to the frame 11 for stable rotation. A vertically downward pulling force is applied to the integral inner ring rotating mechanism via a spindle loading device 9, preventing vertical displacement. Vertically upward and downward forces are applied to the outer ring of the bearing 2 under test via a left loading device 12 and a right loading device 7, bringing it to its upper and lower measurement limit positions. Further, the displacement of the outer ring of the bearing 2 under test between the two limit positions is measured using a left measuring device 1 and a right measuring device 6. The average of the two displacements is the axial clearance of the bearing.
[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.
Claims
1. A device for measuring the axial clearance of a large-size three-point angular contact ball bearing, characterized in that: It includes a left measuring device (1), a bearing under test (2), a pressure cap (3), a bearing inner ring fixture (4), a hollow spindle rotating device (5), a right measuring device (6), a right loading device (7), a spindle bearing housing (8), a spindle loading device (9), a spindle bearing (10), a frame (11), a left loading device (12), a flexible loading disk (13), a base (14), and a bearing outer ring fixture (15). A frame circular hole is opened in the middle of the upper surface of the frame (11). A spindle bearing housing (8) is installed in the frame circular hole of the frame (11). Two spindle bearings (10) are installed inside the spindle bearing housing (8). The hollow spindle rotating device (5) passes through the spindle bearing housing (8) and the frame circular hole in the vertical direction from top to bottom. The hollow spindle rotating device (5) is rotatably connected to the spindle bearing housing (8) through the spindle bearing (10) in the middle. The lower part of the hollow spindle rotating device (5) is connected to the loading end of the spindle loading device (9). The upper part of the hollow spindle rotating device (5) is fitted with a bearing inner ring fixture (4). The left loading device (12) and the right loading device (7) are vertically and symmetrically arranged on the left and right sides of the spindle bearing seat (8). The flexible loading disk (13) is fitted on the spindle bearing seat (8). The lower surface of the flexible loading disk (13) is connected to the loading ends of the left loading device (12) and the right loading device (7) respectively. A base (14) is installed on the flexible loading disk (13). A bearing outer ring fixture (15) is installed on the base (14). The left measuring device (1) and the right measuring device (6) are installed on the left and right sides of the upper surface of the bearing outer ring fixture (15) respectively. The outer ring of the bearing (2) to be measured is installed on the bearing outer ring fixture (15), and the inner ring of the bearing (2) to be measured is installed on the bearing inner ring fixture (4). The hollow spindle rotating device (5) includes a spindle body and a servo motor. The lower end of the spindle body is connected to the rotor of the servo motor through a coupling. The servo motor is connected to the loading end of the spindle loading device (9). The main shaft body is a stepped shaft. From the input end to the output end, the stepped shaft consists of the first shaft section, the second shaft section, the third shaft section, the fourth shaft section and the fifth shaft section. A shoulder A is formed between the first shaft section and the second shaft section. The shoulder A is pressed against the upper surface of the inner ring of the upper main shaft bearing (10). A shoulder B is formed between the second shaft section and the third shaft section. The lower part of the bearing inner ring fixture (4) is located at the third shaft section. The lower surface of the bearing inner ring fixture (4) is pressed against the shoulder B. The upper part of the bearing inner ring fixture (4) and the bearing under test (2) are located at the fourth shaft section. A shoulder C is formed between the fourth shaft section and the fifth shaft section. The pressure cap (3) is located at the fifth shaft section. The fifth shaft section is machined with external threads. The center hole of the pressure cap (3) is machined with internal threads. The pressure cap (3) is threadedly connected to the fifth shaft section. The flexible loading disk (13) includes an upper disk body, a middle flexible sleeve and a lower disk body. The upper disk body, the middle flexible sleeve and the lower disk body are sequentially sleeved on the outside of the main shaft bearing seat (8) from top to bottom. The upper disk body has an upper circular through hole machined in the center and the lower disk body has a lower circular through hole in the center. The circular through hole of the lower disk body can slide with the outer wall of the main shaft bearing seat (8). The middle flexible sleeve is made of rubber material. The upper and lower end faces of the middle flexible sleeve are machined with annular grooves. The lower annular outer edge of the upper disk body is inserted into the upper annular groove of the middle flexible sleeve, and the upper annular outer edge of the lower disk body is inserted into the lower annular groove of the middle flexible sleeve.
2. The axial clearance measuring device for large-size three-point angular contact ball bearings according to claim 1, characterized in that: The inner ring tooling (4) of the bearing has an annular groove that matches the outer ring of the bearing (2) being tested, machined along the circumferential direction on its inner side.
3. The axial clearance measuring device for a large-size three-point angular contact ball bearing according to claim 2, characterized in that: The bearing inner ring fixture (4) has a right-angled annular notch on the outer side along the circumferential direction that matches the inner ring of the bearing (2) being tested.
4. The axial clearance measuring device for large-size three-point angular contact ball bearings according to claim 3, characterized in that: The pressure cap (3) is a circular plate structure. The diameter of the pressure cap (3) is smaller than the outer diameter of the inner ring of the bearing (2) being tested, and the inner diameter of the inner ring of the bearing (2) being tested is smaller than the diameter of the pressure cap (3).
5. The axial clearance measuring device for large-size three-point angular contact ball bearings according to claim 4, characterized in that: The base (14) is a circular plate structure. A circular hole is opened in the center of the base (14). A base sleeve is integrally formed with the base (14) and arranged coaxially. The lower end of the base sleeve is inserted into the circular through hole of the upper part of the flexible loading disk (13).
6. The axial clearance measuring device for large-size three-point angular contact ball bearings according to claim 5, characterized in that: The main spindle bearing housing (8) is a hollow cylindrical structure with openings at both ends. The inner cylindrical surface at the lower end of the main spindle bearing housing (8) is provided with a first annular boss along the radial direction. The upper surface of the first annular boss abuts against the lower end face of the outer ring of the lower bearing. The outer cylindrical surface at the lower end of the main spindle bearing housing (8) is provided with a second annular boss along the radial direction. The lower surface of the second annular boss abuts against the upper surface of the frame (11).
7. A measurement method for the axial clearance measuring device of a large-size three-point angular contact ball bearing according to any one of claims 1 to 6, characterized in that: The method for measuring the axial clearance of large-size three-point angular contact ball bearings is achieved through the following steps: Step 1: Start the control system and set the relevant parameters of the left loading device (12), right loading device (7), hollow spindle rotation device (5) and spindle loading device (9) according to the requirements; Step 2: Using the bearing inner ring fixture (4), the cover (3), and the bearing outer ring fixture (15), the bearing to be tested (2) is fixed on the hollow spindle rotating device (5) to form the inner ring rotating mechanism as a whole. It is fixed on the frame (11) by the spindle bearing (10) and achieves stable rotation. The spindle loading device (9) is started, and a vertical downward pulling force is applied to the inner ring rotating mechanism as a whole through the spindle loading device (9) so that the inner ring rotating mechanism as a whole does not move in the vertical direction. Step 3: Start the hollow spindle rotating device (5) and use the hollow spindle rotating device (5) and the pressure plate (3) to press the bearing (2) under test; then start the left loading device (12) and the right loading device (7) and apply vertical upward and vertical downward forces to the outer ring of the bearing (2) under test through the left loading device (12) and the right loading device (7) to make it reach the upper and lower measurement limit positions; measure the displacement of the outer ring of the bearing (2) under test between the two limit positions through the left measuring device (1) and the right measuring device (6), and the average value of the two displacements is the axial clearance of the bearing; Step 4: After the measurement is completed, turn off the left loading device (12), the right loading device (7), the hollow spindle rotation device (5), and the spindle loading device (9). The test is over.