Method for testing pre-tightening force of paired bearings with space rings arranged in middle
Through the intermediate spacer paired bearing preload test method, the force that pushes the outer spacer is used to measure and research the inner and outer spacer, and solve the problem that the preload test of paired bearings in the prior art is difficult to accurately test. Achieve high-precision preload testing.
Patent Information
- Application Number
- CN202411409920.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-10
- Publication Date
- 2025-02-11
AI Technical Summary
The existing preload test methods for paired bearings are difficult to accurately test the preload value, resulting in the bearings working under unsuitable preload forces, affecting performance and life.
The preloading force test method for the intermediate spacer paired bearing is used, and the force required to push the outer spacer is measured as a reference through the force gauge, and the inner and outer spacer is studied to achieve precise preloading force.
It realizes high accuracy of paired bearing preload test, reduces the impact on bearing accuracy and performance, and is simple to operate and easy to use.
Smart Images
Figure CN119413345A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of bearing pairing, and in particular to a method for testing the preload force of paired bearings with intermediate spacers. Background Art
[0002] At present, the preload test of paired bearings mostly adopts the stiffness test method. When the stiffness change is not obvious, it is difficult to accurately test the preload value, causing the bearing to work under an inappropriate preload. If the preload is too large, the performance of the bearing, such as the friction torque, will increase and the life will be reduced. If the preload is too small, the stiffness of the bearing will be low, the operation accuracy will be low, and even the operation accuracy and performance of the shaft system will be affected.
[0003] In view of the above problems, in order to improve the accuracy of testing the preload force of paired bearings, a testing method for the preload force of paired bearings with an intermediate spacer is proposed. Summary of the invention
[0004] The purpose of the present invention is to propose a method for testing the preload force of paired bearings with an intermediate spacer, using a dynamometer to measure the force required to push the outer spacer under the preload state as a reference, and by grinding the inner and outer spacers, accurate matching of the preload force of paired bearings with an intermediate spacer can be achieved.
[0005] The technical solution adopted by the present invention is: a method for testing the preload force of paired bearings with intermediate spacers, comprising the following steps:
[0006] 1) Assemble two rows of bearings into back-to-back paired bearings, with the axis of the bearings vertical. Install an outer spacer between the two outer rings of the back-to-back paired bearings for support. There is no support between the two rows of inner rings, and the bottom of the lower inner ring is supported and fixed;
[0007] Apply a vertical downward preload load F1 to the upper inner ring. At this time, use a dynamometer to test and record the force f1 pushing the outer spacer along the radial direction of the bearing.
[0008] 2) On the basis of the outer spacer between the two outer rings, an inner spacer is further installed between the two inner rings, and a vertical downward preload F2 is applied to the upper inner ring, so that F2 = F1, and the force f2 pushing the outer spacer at this time is recorded, and then the magnitudes of f2 and f1 are compared;
[0009] 2.1) If f2 is less than f1, the actual preload force is too small, indicating that the height of the inner spacer is too large. The inner spacer height needs to be adjusted until the tested force f2 pushing the outer spacer is equal to f1. Then the back-to-back bearings meet the preload load F1 requirement.
[0010] 2.2) If f2 = f1, apply a vertical downward preload F3 to the upper inner ring, so that F3>F1. At this time, test and record the force f3 pushing the outer spacer, and then compare the size of f3 and f1:
[0011] If f3 = f1, the back-to-back bearing pair meets the preload load F1 requirement;
[0012] If f3>f1, the preload force is too large, indicating that the height of the inner spacer is too low. The height of the outer spacer needs to be adjusted until the tested force f3 pushing the outer spacer is equal to f1. Then the back-to-back paired bearings meet the preload load F1 requirement.
[0013] As a preferred solution, before the bearings are paired, the end surface roughness of the inner and outer spacers is tested, and the inner or outer spacers with the same end surface roughness are selected for pairing, and the initial roughness Ra at this time is recorded;
[0014] After each grinding, the end surface roughness of the grinding end of the inner or outer spacer is made to reach the initial roughness Ra, and then the inner or outer spacer is assembled between two rows of bearings, and then the force pushing the outer spacer is tested.
[0015] As a preferred solution, use a locating shaft for positioning when assembling the inner spacer between the two inner rings:
[0016] Take a positioning shaft with an outer diameter equal to the inner diameter of the inner ring, and put a bearing, an inner spacer, and another bearing on the positioning shaft in sequence, so that the circumferential surface of the positioning shaft supports the inner circumferential surface of the inner ring and the inner spacer respectively. After the inner ring on the lower side is supported and a certain amount of preload is applied to the inner ring on the upper side, the positioning is completed.
[0017] As a preferred solution, when an outer spacer is installed between the two outer rings, the lateral position of the outer spacer is adjusted so that the outer circumferential surface of the outer spacer is aligned with the outer circumferential surface of the outer ring, and then the preload is applied.
[0018] As a preferred solution, when grinding the inner or outer spacer, the grinding amount is calculated using the following formula:
[0019] H=Fd·k
[0020] Among them: H is the amount of repair, Fd is the difference in driving force, that is, Fd = f2-f1 or Fd = f3-f1, and k is the repair coefficient.
[0021] As a preferred solution, after obtaining the grinding amount H, the grinding process and the force of pushing the outer spacer are alternately performed;
[0022] The thickness of the first grinding is H1, leaving a grinding margin of H-H1, where H1 is less than H, H-H1>H s , H s The thickness of H is the minimum precision value that can be achieved by grinding, and the thickness of subsequent single grinding is H s , until the back-to-back bearings meet the preload F1 requirement.
[0023] As a preferred solution, one end of the inner spacer or outer spacer is selected as the grinding end during grinding, and each grinding is performed at this grinding end until the back-to-back paired bearings meet the preload F1 requirement.
[0024] As a preferred solution, before the dynamometer pushes the outer spacer, an initial force measuring point is first marked on the outer circumferential surface of the outer spacer to determine the contact position between the detection axis of the dynamometer and the outer spacer. During the test, the outer spacer is slowly pushed in the radial direction of the outer spacer to record the force that can push the outer spacer.
[0025] When marking the initial force measuring point: first draw a generatrix on the outer circumferential surface of the outer spacer ring, and select the midpoint of the generatrix as the initial force measuring point.
[0026] As a preferred solution, after each grinding of the inner spacer or the outer spacer, a dynamometer is used to measure the force at the same initial force measuring point.
[0027] As a preferred solution, a variable load hydraulic loading device is used to apply a vertical downward preload to the upper inner ring.
[0028] Compared with the prior art, the present invention has the following beneficial effects:
[0029] 1. Since the outer spacer driving force (with outer spacer and no inner spacer) is used as the criterion for the preload force of the paired bearings, it is not affected by the bearing stiffness and does not require a formula for calculation. Therefore, the preload force test of the paired bearings is highly accurate.
[0030] 2. This test method uses two different sizes of preload loads. Compared with the stiffness test preload method which uses a variable load loading method, it is simple to use and easy to operate, and can more effectively reduce the impact of the test process on the bearing accuracy and performance.
[0031] 3. This test method only observes the driving force of the outer spacer from the side, and is simple to use and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS
[0032] 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 invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0033] Figure 1 A schematic diagram of the state of the bearing assembly in the present invention;
[0034] Figure 2 It is a schematic diagram of a state when the preload F1 is applied in the present invention;
[0035] Figure 3 It is a schematic diagram of a state when the preload F2 is applied in the present invention;
[0036] Figure 4 It is a schematic diagram of a state when the preload F3 is applied in the present invention;
[0037] Figure 5 It is a schematic diagram of the state when the present invention reaches the preload F1;
[0038] Figure 6 Schematic diagram of the position of the initial force measuring point in the present invention. DETAILED DESCRIPTION
[0039] The present invention is described in detail below by way of exemplary embodiments. However, it should be understood that, without further description, elements, structures and features in one embodiment may also be beneficially combined in other embodiments.
[0040] It should be noted that: unless otherwise defined, the technical terms or scientific terms used in this document shall have the usual meanings understood by people with ordinary skills in the field to which the invention belongs. The words "one", "an" or "the" and the like used in the patent application specification and claims of the present invention do not express quantity restrictions, but indicate the existence of at least one; the words "first", "second" and "third" used in this document shall not be regarded as restrictions on the order of components, but are only used to distinguish different components; words such as "include" or "comprise" and the like indicate that the elements or objects appearing before "include" or "comprise" include the elements or objects listed after "include" or "comprise" and their equivalents, but do not exclude other elements or objects with the same function.
[0041] In order to more clearly describe the preload test method of the paired bearings with intermediate spacers, Figure 2-6 by Figure 1 The present embodiment is tested and described by taking the back-to-back paired bearing 7206 (103 is a bearing retainer and 104 is a rolling element) with inner and outer spacers in the middle as shown as an example:
[0042] A method for testing the preload force of paired bearings with intermediate spacers, comprising the following steps:
[0043] 1) See Figure 2 Before the bearings are paired, the end surface roughness of the inner spacer 4 and the outer spacer 3 is tested, and the inner spacer 4 or the outer spacer 3 with the same end surface roughness is selected for pairing, and the initial roughness Ra at this time is recorded;
[0044] The two rows of bearings (1, 2) are assembled into a back-to-back paired bearing, the axis of the back-to-back paired bearing is vertical, an outer spacer 3 is installed between the two outer rings (101, 201) of the paired bearing for support, there is no support between the two rows of inner rings (102, 202), and the bottom of the lower inner ring 202 is supported and fixed by a fixing seat 5; when the two rows of bearings are paired, a positioning shaft can be used to support and position the inner rings (102, 202) of the bearings to ensure that the inner rings of the two rows of bearings are aligned;
[0045] After adjusting the lateral position of the outer spacer 3 so that the outer cylindrical surface of the outer spacer 3 is aligned with the outer cylindrical surface of the outer ring (101, 201), a vertical downward preload F1 is applied to the upper inner ring 102 (the preload is provided by an external variable load hydraulic loading device 7, and can also be provided by two fixed-size load loading systems). At this time, the force f1 that pushes the outer spacer is tested and recorded along the radial direction of the bearing through the dynamometer 6; f1 in this state is used as a criterion for judging the bearing preload.
[0046] 2) On the basis of the outer spacer 3 between the two outer rings (101, 201), an inner spacer 4 is further installed between the two inner rings (102, 202);
[0047] When assembling the inner spacer 4 between the two inner rings (102, 202), use the positioning shaft 8 for positioning: take the positioning shaft 8 with an outer diameter equal to the inner diameter of the inner ring, and put a bearing, an inner spacer, and another bearing on the positioning shaft 8 in sequence, so that the circumferential surface of the positioning shaft 8 supports the inner circumferential surface of the inner ring (102, 202) and the inner spacer 4 respectively, and when the lower inner ring 202 is supported by the fixed seat 5 and a certain size of preload F is applied to the upper inner ring 102, the positioning shaft 8 can be withdrawn upward; the contact parts of the fixed seat 5 and the variable load hydraulic loading device 7 with the bearing can be in annular shape, which does not affect the placement and removal of the positioning shaft 8;
[0048] Then, a vertical downward preload F2 is applied to the upper inner ring 102, so that F2 = F1, and the force f2 pushing the outer spacer ring 3 is recorded, and then the magnitudes of f2 and f1 are compared:
[0049] 2.1) If f2<f1, the actual preload force is too small, indicating that the height of the inner spacer 4 is too large. Figure 3 In the state shown, when the inner spacer 4 is too high, the two outer rings (101, 201) lack support and clamping for the outer spacer 3, so it is more labor-saving to push the outer spacer 3. At this time, it is necessary to adjust the height of the inner spacer 4 until the tested force f2 to push the outer spacer 3 is equal to f1. Then the back-to-back paired bearings meet the preload load F1 requirement. Figure 5 Status shown.
[0050] When grinding the inner spacer 4 or the outer spacer 3 in the above process, the following grinding process is adopted:
[0051] First, use the following formula to calculate the amount of training:
[0052] H=Fd·k
[0053] Where: H is the grinding amount (unit: mm), Fd is the difference in driving force (unit: N), that is, Fd = f2-f1, k is the grinding coefficient, taking the back-to-back paired bearing 7206 with inner and outer spacers in the middle as an example, k is
[0054] During the grinding, one end of the inner spacer 4 or the outer spacer 3 is selected as the grinding end, and each grinding is performed at the grinding end. The grinding of the spacer can be performed by a high-precision machine tool or by manual grinding of the electric spindle bearing spacer. The precision range that the machine tool can achieve is about 5 microns, and the precision value of the electric spindle bearing spacer can reach 2 microns by manual grinding. After obtaining the grinding amount H, the grinding process and the force that pushes the outer spacer are alternately performed;
[0055] The thickness of the first grinding is H1, leaving a grinding margin of H-H1, where H1 is less than H, H-H1>H s , H s The thickness of H is the minimum precision value that can be achieved by grinding, and the thickness of subsequent single grinding is H s After each grinding, the end surface roughness of the grinding end of the inner or outer spacer is made to reach the initial roughness Ra, and then the inner or outer spacer is assembled between the two rows of bearings, and then the force pushing the outer spacer is tested until the back-to-back paired bearings meet the preload load F1 requirement.
[0056] 2.2) If f2=f1, there are two situations: one is that the preload F1 is just reached, and the other is that the preload is too large. Therefore, further differentiation is required. A vertical downward preload F3 is applied to the upper inner ring 102 to make F3>F1. After applying the increased preload, the force f3 pushing the outer spacer 3 is tested and recorded, and then the magnitudes of f3 and f1 are compared:
[0057] If f3 = f1, since the height of the inner spacer 4 is appropriate, the increased preload is directly shared by the inner spacer 4, so the force pushing the outer spacer 3 remains unchanged after the preload load increases. It can be determined that the back-to-back paired bearings have met the preload load F1 requirement at this time;
[0058] If f3>f1, that is Figure 4In the situation shown, since the inner spacer 4 cannot effectively share the increased preload, it will be transferred more to the outer spacer 3. Therefore, after the preload increases, the force pushing the outer spacer 3 increases accordingly. At this time, it can be determined that the preload is too large, indicating that the height of the inner spacer 4 is too low. It is necessary to adjust the height of the outer spacer 3 until the tested force f3 pushing the outer spacer 3 = f1. Then the back-to-back paired bearings meet the preload load F1 requirement;
[0059] When grinding the inner spacer ring 4 in the above process, the grinding process described in step 2.1) can also be used until the back-to-back paired bearings meet the preload load F1 requirement, which will not be repeated here.
[0060] In the above example:
[0061] See also Figure 6 In order to reduce the volatility of the test results, before the dynamometer 6 pushes the outer spacer 3, the initial force measuring point is first marked on the outer cylindrical surface of the outer spacer 3 to determine the contact position between the detection axis of the dynamometer 6 and the outer spacer 3. During the test, the outer spacer 3 is slowly pushed along the radial direction of the outer spacer 3 to record the force f that can push the outer spacer 3. When marking the initial force measuring point: first draw a generatrix on the outer cylindrical surface of the outer spacer 3 (the dotted line shown in the figure), and select the midpoint of the generatrix as the initial force measuring point (the circular area in the middle of the dotted line); after each grinding of the inner spacer 4 or the outer spacer 3, use the dynamometer 6 to maintain the same initial force measuring point for force measurement. In order to ensure that the initial force measuring point is always in the middle position of the outer cylindrical surface of the outer spacer 3, the two end faces of the outer spacer 3 can be simultaneously ground.
[0062] The parts not described in detail in the above embodiments are prior art.
[0063] It should be noted that although the present invention is described by the above embodiments, the present invention may also have other various embodiments. Without departing from the spirit and scope of the present invention, it is obvious that those skilled in the art may make various corresponding changes and deformations to the present invention, but these changes and deformations should all fall within the scope of protection of the appended claims of the present invention and their equivalents.
Claims
1. A method for testing the preload force of paired bearings with intermediate spacers, characterized in that: The following steps are involved: 1) Assemble two rows of bearings into back-to-back paired bearings, with the axis of the bearings vertical. Install an outer spacer between the two outer rings of the back-to-back paired bearings for support. There is no support between the two rows of inner rings, and the bottom of the lower inner ring is supported and fixed; Apply a vertical downward preload load F1 to the upper inner ring. At this time, use a dynamometer to test and record the force f1 pushing the outer spacer along the radial direction of the bearing. 2) On the basis of the outer spacer between the two outer rings, an inner spacer is further installed between the two inner rings, and a vertical downward preload F2 is applied to the upper inner ring, so that F2 = F1, and the force f2 pushing the outer spacer at this time is recorded, and then the magnitudes of f2 and f1 are compared; 2.1) If f2 is less than f1, the actual preload force is too small, indicating that the height of the inner spacer is too large. The inner spacer height needs to be adjusted until the tested force f2 pushing the outer spacer is equal to f1. Then the back-to-back bearings meet the preload load F1 requirement. 2.2) If f2 = f1, apply a vertical downward preload F3 to the upper inner ring, so that F3>F1. At this time, test and record the force f3 pushing the outer spacer, and then compare the size of f3 and f1: If f3 = f1, the back-to-back bearing pair meets the preload load F1 requirement; If f3>f1, the preload force is too large, indicating that the height of the inner spacer is too low. The height of the outer spacer needs to be adjusted until the tested force f3 pushing the outer spacer is equal to f1. Then the back-to-back paired bearings meet the preload load F1 requirement.
2. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: Before pairing the bearings, check the end surface roughness of the inner and outer spacers, select the inner or outer spacer with the same end surface roughness for pairing, and record the initial roughness Ra at this time; After each grinding, the end surface roughness of the grinding end of the inner or outer spacer is made to reach the initial roughness Ra, and then the inner or outer spacer is assembled between two rows of bearings, and then the force pushing the outer spacer is tested.
3. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: Use a locating shaft for positioning when assembling an inner spacer between two inner rings: Take a positioning shaft with an outer diameter equal to the inner diameter of the inner ring, and put a bearing, an inner spacer, and another bearing on the positioning shaft in sequence, so that the circumferential surface of the positioning shaft supports the inner circumferential surface of the inner ring and the inner spacer respectively. After the inner ring on the lower side is supported and a certain amount of preload is applied to the inner ring on the upper side, the positioning is completed.
4. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: When installing an outer spacer between two outer rings, adjust the lateral position of the outer spacer so that the outer circumferential surface of the outer spacer is aligned with the outer circumferential surface of the outer ring, and then apply the preload.
5. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: When grinding the inner or outer spacer, use the following formula to calculate the grinding amount: H=Fd·k Among them: H is the amount of repair, Fd is the difference in driving force, that is, Fd = f2-f1 or Fd = f3-f1, and k is the repair coefficient.
6. A method for testing the preload force of paired bearings with intermediate spacers according to claim 5, characterized in that: After obtaining the grinding amount H, the grinding process and the force that pushes the outer spacer are alternately performed; The thickness of the first grinding is H1, leaving a grinding margin of H-H1, where H1 is less than H, H-H1>H s , H s The thickness of H is the minimum precision value that can be achieved by grinding, and the thickness of subsequent single grinding is H s , until the back-to-back bearings meet the preload F1 requirement.
7. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: During grinding, one end of the inner spacer or outer spacer is selected as the grinding end, and each grinding is performed at this grinding end until the back-to-back paired bearings meet the preload load F1 requirement.
8. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: Before the dynamometer pushes the outer spacer, an initial force measuring point is first marked on the outer circumferential surface of the outer spacer to determine the contact position between the detection axis of the dynamometer and the outer spacer. During the test, the outer spacer is slowly pushed along the radial direction of the outer spacer to record the force that can push the outer spacer; When marking the initial force measuring point: first draw a generatrix on the outer circumferential surface of the outer spacer ring, and select the midpoint of the generatrix as the initial force measuring point.
9. A method for testing the preload force of paired bearings with intermediate spacers according to claim 8, characterized in that: After each grinding of the inner or outer spacer, use a dynamometer to measure the force at the same initial force point.
10. A method for testing the preload force of paired bearings with intermediate spacers according to claim 1, characterized in that: A variable load hydraulic loading device is used to apply a vertical downward preload to the upper inner ring.