Method for measuring rigidity of paired main bearings of RV speed reducer

Abstract

The invention discloses a method for measuring the rigidity of paired main bearings of an RV speed reducer. The method comprises the following steps of 1, customizing a bearing mounting tool according to the size of a bearing to be measured; step 2, inputting a test load spectrum and an axial measurement load on the measurement controller; 3, completing the assembly of the bearing installation tool and the two to-be-tested bearings, and connecting a tool upper cover with the top platform; 4, rotating the tool spacer ring and driving the outer rings of the two to-be-tested bearings to rotate, and eliminating gaps between the ferrules of the two to-be-tested bearings and the rolling balls; step 5, applying an axial load to the two to-be-measured bearings until the axial load is consistent with the axial measurement load set on the measurement controller, thereby completing the preloading of the two to-be-measured bearings; step 6, calculating the assembly height of the paired bearings; and step 7, taking the numerical value of the assembly height of the paired bearings as an original point, continuously applying an axial load to the two to-be-tested bearings, and finally drawing a stress-displacement curve by using test data. The method is high in measurement efficiency.

Description

Technical Field

[0001] The invention relates to a method for measuring the stiffness of paired main bearings of an RV reducer. Background Art

[0002] The main bearing of the RV reducer is usually composed of a pair of thin-walled angular contact ball bearings. The installation accuracy and rigidity of the main bearing directly affect the comprehensive performance and expected life of the RV reducer.

[0003] At present, the production of RV reducers is basically done by operators completing bearing inspection and then randomly selecting and matching. The thickness of the support flange and the spacer ring is used to adjust the bearing accuracy and preload stiffness. There are problems such as low selection success rate and low assembly efficiency, which cannot adapt to large-scale mass production.

[0004] The nonlinear deformation caused by the contact between the inner and outer rings and the rolling elements of thin-walled angular contact ball bearings during load-bearing, the change in the oil film thickness between the raceway and the rolling element surface, and the deformation caused by the friction temperature rise of each component will change the stiffness of the bearing, thereby affecting the accuracy of the RV reducer. The actual stiffness of the bearing changes with the installation conditions and working conditions. If the bearing stiffness is still regarded as a fixed static stiffness, it will seriously affect the dynamic performance of the RV reducer.

[0005] The installation preload of the RV reducer requires adjusting the thickness of the support flange and the spacer ring through the assembly height of the paired bearings, so as to approach the preload force required to meet the stiffness. After tightening the bolts, measure the friction torque of the RV reducer to verify whether the preload amount is appropriate.

[0006] With the in-depth research of RV reducer manufacturers, they have gradually begun to require bearing suppliers to provide the dynamic stiffness curve of the bearing, that is, the stress-strain curve, as well as the assembly height data of paired bearings. Summary of the invention

[0007] The purpose of the present invention is to overcome the defects of the prior art and provide a method for measuring the stiffness of paired main bearings of RV reducers, which solves the problem of high assembly and low measurement efficiency when paired main bearings of RV reducers are selected.

[0008] The object of the present invention is achieved as follows: a method for measuring the stiffness of paired main bearings of an RV reducer, based on a measuring device for the stiffness of paired main bearings of an RV reducer, the measuring device comprising a base, a top platform, an axial loading assembly, a bearing mounting tool, a bearing drive assembly, a force sensor, at least two first distance sensors, two second distance sensors and a measurement controller; wherein,

[0009] A circular mounting groove is provided at the center of the top surface of the base;

[0010] The top platform is located above the base;

[0011] The axial loading assembly includes a load transfer shaft coaxially connected to the center of the bottom surface of the top platform with the mounting groove of the base, and four electric hydraulic rods centrally and symmetrically hinged between the peripheral top surface of the mounting groove of the base and the bottom surface of the top platform;

[0012] The bearing installation tool comprises a tool lower cover, a tool spacer ring and a tool upper cover which are coaxially arranged from bottom to top; a bearing upper shaft whose diameter matches the inner diameter of the bearing to be tested is provided on the top surface of the tool lower cover, and a flange matching the mounting groove on the base is provided at the center of the bottom surface of the tool lower cover, so that the tool lower cover is installed in the mounting groove of the base; a convex ring is retracted in the middle of the tool spacer ring, so that the upper and lower parts of the tool spacer ring each form a bearing mounting groove matching the outer ring of the bearing to be tested; a bearing lower shaft whose diameter matches the inner diameter of the bearing to be tested is provided on the bottom surface of the tool upper cover, and the tool upper cover is coaxially connected to the bottom of the load transfer shaft;

[0013] The bearing drive assembly includes four roller brackets fixed symmetrically on the outer peripheral top surface of the mounting groove of the base and located on the inner side of the four axial telescopic rods, an active roller mounted on one roller bracket and tangent to the middle of the outer surface of the tooling spacer ring, three passive rollers mounted on the other three roller brackets in a one-to-one correspondence and tangent to the middle of the outer surface of the tooling spacer ring, and a roller drive motor mounted on one bracket and drivingly connected to the active roller;

[0014] The force sensor is mounted on the load transfer shaft of the axial loading assembly;

[0015] Two first distance sensors are mounted on the top surface of the base and the bottom surface of the top platform in a one-to-one correspondence;

[0016] Two second distance sensors are mounted on the top surface of the tooling lower cover and the bottom surface of the working upper cover in a one-to-one correspondence;

[0017] The measurement controller is respectively connected to the force sensor, two first distance sensors, two second distance sensors and four electric hydraulic rods by signal.

[0018] The method for measuring the stiffness of paired main bearings of an RV reducer of the present invention comprises the following steps:

[0019] Step 1: Customize the bearing installation tooling according to the size of the bearing to be tested;

[0020] Step 2: input the test load spectrum and axial measurement load on the measurement controller;

[0021] Step three, first install the lower cover of the tooling in the bearing installation tooling into the installation groove of the base, then put the first bearing to be tested on the lower shaft of the bearing on the top surface of the tooling lower cover, and then put the outer ring of the first bearing to be tested into the lower bearing installation groove of the tooling spacer ring, and then install the second bearing to be tested in the upper bearing installation groove of the tooling spacer ring, and then insert the upper shaft of the bearing on the bottom surface of the tooling upper cover into the inner ring of the second bearing to be tested, that is, complete the assembly of the bearing installation tooling and the two bearings to be tested, and finally connect the tooling upper cover to the top platform through the load transfer shaft;

[0022] Step 4: first adjust the positions of the four roller brackets according to the outer diameter of the tooling spacer ring, so that the three passive rollers and one active roller are tangent to the middle of the outer surface of the tooling spacer ring, and then drive the roller drive motor to rotate the tooling spacer ring, so that the tooling spacer ring rotates with the outer rings of the two bearings to be tested, and the gap between the ferrules of the two bearings to be tested and the rolling balls is eliminated by the rotation of the tooling spacer ring;

[0023] Step 5: first adjust the force sensor to zero, then control the four electric hydraulic rods to retract, so that the top platform descends, and apply axial loads to the two bearings to be tested until the value displayed by the force sensor is consistent with the axial measurement load set on the measurement controller, that is, the preload of the two bearings to be tested is completed;

[0024] Step 6, respectively read the value L1 of the second distance sensor installed on the tooling upper cover and the value L3 of the second distance sensor installed on the tooling lower cover; the axial distance between the bottom surface of the tooling upper cover and the top surface of the tooling lower cover is obtained as (L1+L3) / 2, and then the assembly height H0 of the paired bearings is calculated according to the following formula:

[0025] H0=(L1+L3) / 2-X

[0026] X is the height of the convex ring on the tooling spacer ring;

[0027] Step 7: With the value of the assembly height H0 of the paired bearings as the origin, control the four electric hydraulic rods to retract, so that the top platform continues to descend, and continue to apply axial loads to the two bearings to be tested. The measurement controller records the value changes of the force sensor and the distance sensor according to the input test load spectrum; reads the value L1' of the second distance sensor installed on the upper cover of the tooling and the value L2' of the second distance sensor installed on the lower cover of the tooling respectively; and then calculates the assembly height H0' of the paired bearings according to the following formula:

[0028] H0'=(L1'+L3') / 2-X

[0029] The change in the assembly height of the paired bearings is ΔH = H0'-H0

[0030] Read the value on the force sensor: ΔF

[0031] Finally, the stress ΔF is used as the horizontal axis and the change in the assembly height of the paired bearings ΔH is used as the vertical axis to draw a stress-displacement curve using the test data.

[0032] In the above-mentioned method for measuring the stiffness of paired main bearings of an RV reducer, the bottom of the load transfer shaft is connected to the tooling upper cover via a pressure plate.

[0033] In the above-mentioned method for measuring the stiffness of paired main bearings of an RV reducer, the roller drive motor of the bearing drive assembly is also connected to the active roller via a gear transmission mechanism or a belt transmission mechanism.

[0034] The above-mentioned method for measuring the stiffness of paired main bearings of RV reducer, wherein, when performing steps six and seven, first read the value of the first distance sensor installed on the top platform and the value of the first distance sensor installed on the base respectively. If the values ​​of the two first distance sensors are consistent, the surface measurement system is horizontal and there is no additional overturning moment.

[0035] The characteristics of the method for measuring the stiffness of paired main bearings of RV reducer of the present invention are:

[0036] 1. The assembly height and stiffness test of a pair of bearings can be completed through a single measurement, which can help manufacturers quickly complete the matching of the main bearings of the RV reducer, and solve the problem of low assembly height measurement efficiency when the main bearings of the RV reducer are matched in pairs;

[0037] 2. The bearing stiffness curve obtained through measurement can help RV reducer manufacturers better formulate the preload of the reducer, and can also better evaluate the expected life and comprehensive performance of the reducer;

[0038] 3. The tooling spacer ring in the bearing installation tooling of the measuring device simulates the cycloid disk of the RV reducer, which can be customized according to the size of the bearing, convenient for changing the model at any time, and has a simple structure, high reliability, easy disassembly and high maintainability;

[0039] 4. The bearing installation tool can be designed according to the installation dimensions of the RV reducer, so that the test conditions are consistent with the actual working conditions, and the measurement data has more practical reference value;

[0040] 5. Due to the simple structure and compatibility of the measuring device, it can be incorporated into the automated line, and the industrial robot is responsible for the loading and unloading and measuring process, taking into account both efficiency and safety;

[0041] 6. The measuring device also takes into account scalability. In the future, it can be equipped with a friction torque detector and an angular stiffness detection system, which is diversified and customizable. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is an axial cross-sectional view of a device for measuring the stiffness of paired main bearings of an RV reducer adopted in the present invention;

[0043] Figure 2 It is an axial cross-sectional view of the bearing installation tool in the measuring device used in the present invention. DETAILED DESCRIPTION

[0044] The present invention will be further described below in conjunction with the accompanying drawings.

[0045] See also Figure 1 and Figure 2 The method for measuring the stiffness of paired main bearings of an RV reducer of the present invention is based on a measuring device for the stiffness of paired main bearings of an RV reducer, which includes a base 1, a top platform 2, an axial loading assembly, a bearing mounting tool, a bearing drive assembly, at least two first distance sensors 9a, two second distance sensors 9b and a measurement controller.

[0046] A circular mounting groove 10 is provided at the center of the top surface of the base 1 .

[0047] The top platform 2 is located above the base 1 .

[0048] The axial loading assembly includes a load transfer shaft 3 coaxially connected to the mounting groove 10 of the base 1 at the center of the bottom surface of the top platform 1 and four electric hydraulic rods 5 symmetrically hinged between the outer top surface of the mounting groove 10 of the base 1 and the bottom surface of the top platform 2; a pressure plate 30 is coaxially connected to the bottom of the load transfer shaft 3.

[0049] The bearing installation tooling includes a tooling lower cover 61, a tooling spacer ring 62 and a tooling upper cover 63 which are coaxially arranged from bottom to top; wherein, a bearing upper shaft whose diameter matches the inner diameter of the bearing to be tested is provided on the top surface of the tooling lower cover 61, and a flange matching the mounting groove 10 on the base 1 is provided at the center of the bottom surface of the tooling lower cover 61, so that the tooling lower cover 61 can be installed in the mounting groove 10 of the base 1; a convex ring is retracted in the middle part of the tooling spacer ring 62, so that the upper and lower parts of the tooling spacer ring 62 each form a bearing mounting groove matching the outer ring of the bearing to be tested; the bottom surface of the tooling upper cover 63 is provided with a bearing lower shaft whose diameter matches the inner diameter of the bearing to be tested, and the tooling upper cover 63 is coaxially connected to the bottom surface of the pressure plate 30 at the bottom of the load transfer shaft.

[0050] The bearing drive assembly includes four roller brackets 7 which are symmetrically fixed on the outer top surface of the mounting groove 10 of the base 1 and located on the inner side of the four electric hydraulic rods 5, an active roller 7a installed on one roller bracket 7 and tangent to the middle of the outer surface of the tooling spacer ring 62, three passive rollers 7b which are installed one by one on the other three roller brackets 7 and tangent to the middle of the outer surface of the tooling spacer ring 62, and a roller drive motor 8 which is installed on one roller bracket 7 and is driven and connected to the active roller 7a through a gear transmission mechanism or a belt transmission mechanism.

[0051] The force sensor 4 is mounted on the load transfer shaft 3 in the axial loading assembly.

[0052] The two first distance sensors 9 a are mounted on the top surface of the base 1 and the bottom surface of the top platform 2 in a one-to-one correspondence.

[0053] The two second distance sensors 9 b are mounted on the top surface of the tooling lower cover 61 and the bottom surface of the working upper cover 63 in a one-to-one correspondence.

[0054] The measurement controller is signal-connected to the force sensor 4 , the two first distance sensors 9 a , the two second distance sensors 9 b and the four electric hydraulic rods 5 , respectively.

[0055] The method for measuring the stiffness of paired main bearings of an RV reducer of the present invention comprises the following steps:

[0056] Step 1: Customize the bearing installation tooling according to the size of the bearing to be tested;

[0057] Step 2: Input the test load spectrum on the measurement controller. The test load spectrum is provided by the reducer manufacturer, i.e., the working load table for the performance test of the reducer after installation; and set the axial measurement load of the bearing on the measurement controller according to Table 3 and Table 4 of 5.6 of the national standard GB / T307.2-2005;

[0058] Step three, first install the tooling lower cover 61 in the bearing installation tooling into the installation groove 10 of the base 1, then put the first bearing 6A to be tested on the bearing lower shaft on the top surface of the tooling lower cover 61, and then put the outer ring of the first bearing 6A to be tested into the lower bearing installation groove of the tooling spacer ring 62, and then install the second bearing 6B to be tested in the upper bearing installation groove of the tooling spacer ring, and then insert the bearing upper shaft on the bottom surface of the tooling upper cover 63 into the inner ring of the second bearing 6B to be tested, that is, complete the assembly of the bearing installation tooling and the two bearings 6A and 6B to be tested, and finally connect the tooling upper cover 63 to the top platform 2 through the pressure plate 30 at the bottom of the load transfer shaft 3;

[0059] Step 4: first adjust the positions of the four roller brackets 7 according to the outer diameter of the tooling spacer ring 62, so that the three passive rollers 7b and the one active roller 7a are tangent to the middle of the outer surface of the tooling spacer ring 62, and then drive the roller drive motor 8 to rotate the tooling spacer ring 62, so that the tooling spacer ring 62 rotates with the outer rings of the two bearings 6A and 6B to be tested, and the gap between the ferrules of the two bearings 6A and 6B to be tested and the rolling balls is eliminated by the rotation of the tooling spacer ring 62;

[0060] Step 5: first adjust the force sensor 4 to zero, then control the four electric hydraulic rods 5 to contract, so that the top platform 2 descends, and apply axial load to the two bearings 6A and 6B to be tested, until the value displayed by the force sensor 4 is consistent with the axial measurement load set on the measurement controller, that is, the preload of the two bearings 6A and 6B to be tested is completed;

[0061] Step six, first read the value of the first distance sensor 9a installed on the top platform 2 and the value of the first distance sensor 9a installed on the base 1 respectively. If the values ​​of the two first distance sensors 9a are consistent, it means that the top surface of the tooling upper cover 63 and the top surface of the tooling lower cover 61 are horizontal, and there is no additional overturning moment; then read the value L1 of the second distance sensor 9b installed on the tooling upper cover 63 and the value L3 of the second distance sensor 9b installed on the tooling lower cover 61 respectively; the axial distance between the bottom surface of the tooling upper cover 63 and the top surface of the tooling lower cover 61 is obtained as (L1+L3) / 2, and then the assembly height H0 of the paired bearings is calculated according to the following formula:

[0062] H0=(L1+L3) / 2-X

[0063] X is the height of the convex ring on the tooling spacer ring 62;

[0064] Step 7, taking the assembly height H0 value of the paired bearings as the origin, and then controlling the four electric hydraulic rods 5 to contract, so that the top platform 2 continues to descend, and the axial load continues to be applied to the two bearings 6A and 6B to be tested, and the value changes of the force sensor 4 and the distance sensor are recorded according to the input test load spectrum; first read the value of the first distance sensor 9a installed on the top platform 2 and the value of the first distance sensor 9a installed on the base 1 respectively. If the values ​​of the two first distance sensors 9a are consistent, the surface measurement system is horizontal and there is no additional overturning moment; if the values ​​of the two first distance sensors 9a are inconsistent during the loading process, it is necessary to pause the loading and check the cause of the overturning moment. The loading test can be continued after the problem is solved; then read the value L1' of the second distance sensor 9b installed on the tooling upper cover 63 and the value L2' of the second distance sensor 9b installed on the tooling lower cover 61 respectively; and then calculate the assembly height H0' of the bearing according to the following formula:

[0065] H0'=(L1'+L3') / 2-X

[0066] Displacement of assembly height ΔH=H0'-H0

[0067] And at the same time read the value on force sensor 4: ΔF

[0068] Finally, the stress ΔF is used as the horizontal axis and the change in the assembly height of the paired bearings ΔH is used as the vertical axis to draw a stress-displacement curve using the test data.

[0069] The above embodiments are only used to illustrate the present invention, rather than to limit the present invention. Those skilled in the relevant technical field may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also belong to the scope of the present invention and should be defined by the claims.

Claims

1. A method for measuring the stiffness of paired main bearings of an RV reducer, based on a measuring device for the stiffness of paired main bearings of an RV reducer, the measuring device comprising a base, a top platform, an axial loading assembly, a bearing mounting tool, a bearing drive assembly, a force sensor, at least two first distance sensors, two second distance sensors and a measurement controller; wherein, A circular mounting groove is provided at the center of the top surface of the base; The top platform is located above the base; The axial loading assembly includes a load transfer shaft coaxially connected to the center of the bottom surface of the top platform with the mounting groove of the base, and four electric hydraulic rods centrally and symmetrically hinged between the peripheral top surface of the mounting groove of the base and the bottom surface of the top platform; The bearing installation tool comprises a tool lower cover, a tool spacer ring and a tool upper cover which are coaxially arranged from bottom to top; a bearing upper shaft whose diameter matches the inner diameter of the bearing to be tested is provided on the top surface of the tool lower cover, and a flange matching the mounting groove on the base is provided at the center of the bottom surface of the tool lower cover, so that the tool lower cover is installed in the mounting groove of the base; a convex ring is retracted in the middle of the tool spacer ring, so that the upper and lower parts of the tool spacer ring each form a bearing mounting groove matching the outer ring of the bearing to be tested; a bearing lower shaft whose diameter matches the inner diameter of the bearing to be tested is provided on the bottom surface of the tool upper cover, and the tool upper cover is coaxially connected to the bottom of the load transfer shaft; The bearing drive assembly includes four roller brackets fixed symmetrically on the outer peripheral top surface of the mounting groove of the base and located on the inner side of the four axial telescopic rods, an active roller mounted on one roller bracket and tangent to the middle of the outer surface of the tooling spacer ring, three passive rollers mounted on the other three roller brackets in a one-to-one correspondence and tangent to the middle of the outer surface of the tooling spacer ring, and a roller drive motor mounted on one bracket and drivingly connected to the active roller; The force sensor is mounted on the load transfer shaft of the axial loading assembly; Two first distance sensors are mounted on the top surface of the base and the bottom surface of the top platform in a one-to-one correspondence; Two second distance sensors are mounted on the top surface of the tooling lower cover and the bottom surface of the working upper cover in a one-to-one correspondence; The measurement controller is respectively connected to the force sensor, two first distance sensors, two second distance sensors and four electric hydraulic rods by signal. Characterized in that the measuring method comprises the following steps: Step 1: Customize the bearing installation tooling according to the size of the bearing to be tested; Step 2: input the test load spectrum and axial measurement load on the measurement controller; Step three, first install the lower cover of the tooling in the bearing installation tooling into the installation groove of the base, then put the first bearing to be tested on the lower shaft of the bearing on the top surface of the tooling lower cover, and then put the outer ring of the first bearing to be tested into the lower bearing installation groove of the tooling spacer ring, and then install the second bearing to be tested in the upper bearing installation groove of the tooling spacer ring, and then insert the upper shaft of the bearing on the bottom surface of the tooling upper cover into the inner ring of the second bearing to be tested, that is, complete the assembly of the bearing installation tooling and the two bearings to be tested, and finally connect the tooling upper cover to the top platform through the load transfer shaft; Step 4: first adjust the positions of the four roller brackets according to the outer diameter of the tooling spacer ring, so that the three passive rollers and one active roller are tangent to the middle of the outer surface of the tooling spacer ring, and then drive the roller drive motor to rotate the tooling spacer ring, so that the tooling spacer ring rotates with the outer rings of the two bearings to be tested, and the gap between the ferrules of the two bearings to be tested and the rolling balls is eliminated by the rotation of the tooling spacer ring; Step 5: first adjust the force sensor to zero, then control the four electric hydraulic rods to retract, so that the top platform descends, and apply axial loads to the two bearings to be tested until the value displayed by the force sensor is consistent with the axial measurement load set on the measurement controller, that is, the preload of the two bearings to be tested is completed; Step 6, respectively read the value L1 of the second distance sensor installed on the tooling upper cover and the value L3 of the second distance sensor installed on the tooling lower cover; the axial distance between the bottom surface of the tooling upper cover and the top surface of the tooling lower cover is obtained as (L1+L3) / 2, and then the assembly height H0 of the paired bearings is calculated according to the following formula: H0=(L1+L3) / 2-X X is the height of the convex ring on the tooling spacer ring; Step 7: With the value of the assembly height H0 of the paired bearings as the origin, control the four electric hydraulic rods to retract, so that the top platform continues to descend, and continue to apply axial loads to the two bearings to be tested. The measurement controller records the value changes of the force sensor and the distance sensor according to the input test load spectrum; reads the value L1' of the second distance sensor installed on the upper cover of the tooling and the value L2' of the second distance sensor installed on the lower cover of the tooling respectively; and then calculates the assembly height H0' of the paired bearings according to the following formula: H0'=(L1'+L3') / 2-X The change in the assembly height of the paired bearings is ΔH = H0'-H0 Read the value on the force sensor: ΔF Finally, the stress ΔF is used as the horizontal axis and the change in the assembly height of the paired bearings ΔH is used as the vertical axis to draw a stress-displacement curve using the test data.

2. The method for measuring the stiffness of paired main bearings of an RV reducer according to claim 1, characterized in that: The bottom of the load transfer shaft is connected to the tooling upper cover via a pressure plate.

3. The method for measuring the stiffness of paired main bearings of RV reducer according to claim 1, characterized in that: The roller drive motor of the bearing drive assembly is also connected to the active roller through a gear transmission mechanism or a belt transmission mechanism.

4. The method for measuring the stiffness of paired main bearings of an RV reducer according to claim 1, characterized in that: When performing steps six and seven, first read the value of the first distance sensor installed on the top platform and the value of the first distance sensor installed on the base respectively. If the values ​​of the two first distance sensors are consistent, the surface measurement system is horizontal and there is no additional overturning moment.

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