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

Abstract

The utility model discloses a device for measuring rigidity of paired main bearings of an RV reducer. The device comprises a base, a top platform, an axial loading assembly, a bearing installation tool, a bearing driving assembly, a force sensor and at least four distance sensors. The axial loading assembly comprises a load transmission shaft connected to the center of the bottom face of the top platform and four electric hydraulic rods hinged between the top face of the base and the bottom face of the top platform in a central symmetry mode. The bearing mounting tool comprises a tool lower cover, a tool spacer ring and a tool upper cover which are coaxially arranged from bottom to top; the bearing driving assembly comprises a driving roller tangent to the middle of the outer surface of the tool spacer ring and three driven rollers tangent to the middle of the outer surface of the tool spacer ring. The force sensor is mounted on the load transmission shaft; the four distance sensors are installed on the top face of the base, the bottom face of the top platform, the top face of the tool lower cover and the bottom face of the working upper cover. The device is simple in structure, high in reliability and high in maintainability.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of measuring device for RV speed reducer pair main bearing stiffness. BACKGROUND

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

[0003] Currently, the production of RV speed reducer is basically completed by the operator after bearing detection and then randomly selected, and the thickness of support flange and spacer ring is used to adjust the accuracy and pre-tightening stiffness of the bearing, which has the problems of low selection success rate and low assembly efficiency, and cannot adapt to large-scale production.

[0004] The nonlinear deformation generated by the contact between the inner and outer rings and the rolling elements during the bearing process, the change of the oil film thickness on the raceway and the rolling element surface, and the deformation generated by the friction temperature rise of each component will change the stiffness of the bearing, thereby affecting the accuracy of the RV speed reducer. The actual stiffness of the bearing changes with the installation conditions and working conditions. If the bearing stiffness is still considered as a fixed static stiffness, it will seriously affect the dynamic performance of the RV speed reducer.

[0005] The installation and pre-tightening of the RV speed reducer need to adjust the thickness of the support flange and the spacer ring through the assembly of the paired bearings, so as to approach the required pre-tightening force of the stiffness, and then measure the friction torque of the RV speed reducer after tightening with bolts, to check whether the pre-tightening amount is appropriate.

[0006] With the in-depth research of RV speed reducer manufacturers, the bearing suppliers are now gradually required to provide the dynamic stiffness curve of the bearing, i.e. the stress-strain curve, and the assembly height data of the paired bearings. INVENTION CONTENTS

[0007] The utility model aims at overcoming the defects of the prior art and providing a kind of measuring device for RV speed reducer pair main bearing stiffness, which solves the problem of low assembly height measurement efficiency when RV speed reducer main bearing is paired and selected.

[0008] The utility model aims at overcoming the defects of the prior art and providing a kind of measuring device for RV speed reducer pair main bearing stiffness, which solves the problem of low assembly height measurement efficiency when RV speed reducer main bearing is paired and selected.

[0009] A mounting groove with a flat circular top surface is formed in the center of the top surface of the base;

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

[0011] The axial loading assembly comprises a load transmission shaft coaxially connected to the center of the bottom surface of the top platform and four electro-hydraulic rods 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 arranged coaxially from bottom to top; the top surface of the tool lower cover is provided with a bearing upper shaft with a diameter matched with the inner diameter of the bearing to be measured, and the bottom center of the tool lower cover is provided with a flange matched with the mounting groove of the base, so that the tool lower cover is installed in the mounting groove of the base; the middle part of the tool spacer ring is recessed by a convex ring, so that the upper part and the lower part of the tool spacer ring each form a bearing installation groove matched with the outer ring of the bearing to be measured; the bottom surface of the tool upper cover is provided with a bearing lower shaft with a diameter matched with the inner diameter of the bearing to be measured, and the tool upper cover is coaxially connected to the bottom of the load transmission shaft;

[0013] The bearing driving assembly comprises four roller supports fixed symmetrically on the peripheral top surface of the mounting groove of the base and located on the inner side of the four axial telescopic rods, a driving roller installed on one roller support and tangent to the middle part of the outer surface of the tool spacer ring, three driven rollers each installed on another three roller supports and tangent to the middle part of the outer surface of the tool spacer ring, and a roller driving motor installed on a support and drivingly connected with the driving roller;

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

[0015] Two first distance sensors are each installed on the top surface of the base and the bottom surface of the top platform;

[0016] Two second distance sensors are each installed on the top surface of the tool lower cover and the bottom surface of the tool upper cover;

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

[0018] The measurement device for the stiffness of the pair of main bearings of the RV reducer, wherein the bottom of the load transmission shaft is connected with the tool upper cover through a pressing disc.

[0019] The measurement device for the stiffness of the pair of main bearings of the RV reducer, wherein the roller driving motor of the bearing driving assembly is further connected with the driving roller through a gear transmission mechanism or a belt transmission mechanism.

[0020] The measurement device for the stiffness of the pair of main bearings of the RV reducer has the following characteristics:

[0021] 1. The single measurement can complete the assembly height and stiffness detection of a pair of bearings, which can help manufacturers quickly complete the selection of RV reducer main bearing, and solve the problem of low assembly height measurement efficiency when selecting RV reducer main bearing in pairs;

[0022] 2. The bearing stiffness curve measured by the device can help RV reducer manufacturers better determine the pre-tightening amount of the reducer, and better evaluate the expected life and overall performance of the reducer;

[0023] 3. The bearing installation tooling of the measuring device can simulate the RV reducer's cycloid disc, and can be customized according to the size of the bearing, which is convenient for type detection at any time, has simple structure, high reliability, is easy to disassemble, and has high maintainability;

[0024] 4. The bearing installation tooling can be designed according to the installation size 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;

[0025] 5. Due to the simple structure and compatibility of the measuring device, it can be integrated into automatic connection, and the feeding and discharging and measurement process are completed by an industrial robot, which takes into account efficiency and safety;

[0026] 6. The measuring device also takes into account the expandability, and can be further equipped with a friction torque detector and an angular stiffness detection system, and is diversified and customizable. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the axial sectional view of the measuring device for the stiffness of the paired main bearing of the RV reducer of the utility model;

[0028] Figure 2 is the axial sectional view of the bearing installation tooling in the measuring device. DETAILED DESCRIPTION

[0029] The utility model will be further described below with reference to the drawings.

[0030] Please refer to Figure 1 and Figure 2 The measuring device for the stiffness of the paired main bearing of the RV reducer of the utility model comprises a base 1, a top platform 2, an axial loading assembly, a bearing installation tooling, a bearing driving assembly, at least two first distance sensors 9a, two second distance sensors 9b and a measurement controller.

[0031] A mounting groove 10 in the form of a flat circle is formed in the center of the top surface of the base 1.

[0032] The top platform 2 is located above the base 1.

[0033] The axial loading assembly comprises a load transmission shaft 3 coaxially connected to the center of the bottom surface of the top platform 1 in the mounting groove 10 of the base 1 and four electro-hydraulic rods 5 symmetrically hinged between the peripheral top surface of the mounting groove 10 of the base 1 and the bottom surface of the top platform 2; the bottom of the load transmission shaft 3 is coaxially connected with a pressing disc 30.

[0034] The bearing installation tooling comprises a tooling lower cover 61, a tooling spacing ring 62 and a tooling upper cover 63 arranged coaxially from bottom to top; wherein the top surface of the tooling lower cover 61 is provided with a bearing upper shaft with a diameter matched with the inner diameter of the bearing to be measured, the bottom center of the tooling lower cover 61 is provided with a flange matched with the mounting groove 10 on the base 1, so that the tooling lower cover 61 is installed in the mounting groove 10 of the base 1; the middle part of the tooling spacing ring 62 is inwardly recessed by a convex ring, so that the upper part and the lower part of the tooling spacing ring 62 each form a bearing installation groove matched with the outer ring of the bearing to be measured; the bottom surface of the tooling upper cover 63 is provided with a bearing lower shaft with a diameter matched with the inner diameter of the bearing to be measured, and the tooling upper cover 63 is coaxially connected to the bottom surface of the pressing disc 30 at the bottom of the load transmission shaft.

[0035] The bearing driving assembly comprises four roller supports 7 fixed symmetrically on the peripheral top surface of the mounting groove 10 of the base 1 and located on the inner side of the four electro-hydraulic rods 5, a driving roller 7a installed on one roller support 7 and tangent to the middle part of the outer surface of the tooling spacing ring 62, three driven rollers 7b each installed on another three roller supports 7 and tangent to the middle part of the outer surface of the tooling spacing ring 62, and a roller driving motor 8 installed on one roller support 7 and drivingly connected with the driving roller 7a through a gear transmission mechanism or a belt transmission mechanism.

[0036] The force sensor 4 is installed on the load transmission shaft 3 in the axial loading assembly.

[0037] The two first distance sensors 9a are each installed on the top surface of the base 1 and the bottom surface of the top platform 2.

[0038] The two second distance sensors 9b are each installed on the top surface of the tooling lower cover 61 and the bottom surface of the tooling upper cover 63.

[0039] The measurement controller is signal connected with the force sensor 4, the two first distance sensors 9a, the two second distance sensors 9b and the four electro-hydraulic rods 5 respectively.

[0040] The measurement device for the stiffness of the pair of main bearings of the RV reducer of the utility model comprises the following steps during measurement:

[0041] Step one, customizing the bearing installation tooling according to the size of the bearing to be measured;

[0042] Step two, input the test load spectrum on the measuring controller, the test load spectrum is provided by the reducer manufacturer, that is, the working condition load table of performance test after the reducer is installed; and the axial measurement load of the bearing is set on the measuring controller according to table 3 and table 4 in 5.6 of national standard GB / T307.2-2005;

[0043] Step three, first, install the lower cover 61 of the bearing installation tool in the installation groove 10 of the base 1, then, install the first bearing 6A to be measured on the lower bearing shaft on the top surface of the lower cover 61, then, install the second bearing 6B to be measured in the upper bearing installation groove of the tool spacing ring 62, then, insert the upper bearing shaft on the bottom surface of the upper cover 63 into the inner ring of the second bearing 6B to be measured, that is, the assembly of the bearing installation tool and the two bearings 6A and 6B to be measured is completed, and finally, connect the upper cover 63 of the tool with the top platform 2 through the pressure plate 30 at the bottom of the load transmission shaft 3;

[0044] Step four, first, adjust the positions of the four roller supports 7 according to the outer diameter of the tool spacing ring 62, so that the three passive rollers 7b and one active roller 7a are tangent to the middle part of the outer surface of the tool spacing ring 62, then, drive the roller drive motor 8 to rotate the tool spacing ring 62, so that the tool spacing ring 62 rotates with the outer rings of the two bearings 6A and 6B to be measured, and the gap between the rings and the rolling balls of the two bearings 6A and 6B to be measured is eliminated by the rotation of the tool spacing ring 62;

[0045] Step five, first, zero the force sensor 4, then, control the four electric hydraulic rods 5 to retract, so that the top platform 2 descends to apply an axial load to the two bearings 6A and 6B to be measured, until the value displayed by the force sensor 4 is consistent with the axial measurement load set on the measuring controller, that is, the preloading of the two bearings 6A and 6B to be measured is completed;

[0046] Step six, first, read the values of the first distance sensors 9a installed on the top platform 2 and the base 1 respectively, if the values of the two first distance sensors 9a are consistent, it indicates that the top surface of the upper cover 63 and the top surface of the lower cover 61 are horizontal, without additional overturning moment; then, read the values L1 and L3 of the second distance sensors 9b installed on the upper cover 63 and the lower cover 61 respectively; obtain the axial distance between the bottom surface of the upper cover 63 and the top surface of the lower cover 61 as (L1+L3) / 2, and then calculate the assembly height H0 of the pair of bearings according to the following formula:

[0047] H0=(L1+L3) / 2-X

[0048] X is the height of the convex ring on the tool spacing ring 62;

[0049] Step 7: Using the assembly height H0 of the paired bearings as the origin, control the retraction of the four electro-hydraulic rods 5 to continue lowering the top platform 2, and continue applying axial load to the two bearings 6A and 6B to be tested. Record the changes in the values ​​of the force sensor 4 and the distance sensor according to the input test load spectrum. First, read the values ​​of the first distance sensor 9a installed on the top platform 2 and the first distance sensor 9a installed on the base 1. 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 loading, loading needs to be paused to check the cause of the overturning moment. Loading and testing can only continue after troubleshooting. Then, read the values ​​L1' of the second distance sensor 9b installed on the upper cover 63 of the fixture and L2' of the second distance sensor 9b installed on the lower cover 61 of the fixture. Then calculate the assembly height H0' of the bearings according to the following formula:

[0050] H0' = (L1' + L3') / 2 - X

[0051] The change in the assembly height of paired bearings is ΔH = H0' - H0

[0052] And simultaneously read the value from force sensor 4: ΔF

[0053] Finally, using the stress ΔF as the horizontal axis and the change in the assembly height of the paired bearings ΔH as the vertical axis, a stress-displacement curve was plotted using the experimental data.

[0054] The above embodiments are for illustrative purposes only and are not intended to limit the present invention. Those skilled in the art can make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions should also fall within the scope of the present invention and should be defined by the claims.

Claims

1. A device for measuring the stiffness of a pair of main bearings of an RV reducer, comprising a base, a top platform, an axial loading assembly, a bearing installation tool, a bearing driving assembly, a force sensor, at least two first distance sensors, two second distance sensors and a measurement controller; characterized in that, a flat circular mounting groove is formed in the center of the top surface of the base; the top platform is located above the base; the axial loading assembly comprises a load transmission shaft coaxially connected to the mounting groove of the base at the center of the bottom surface of the top platform, and four electro-hydraulic rods 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 arranged coaxially from bottom to top; the top surface of the tool lower cover is provided with a bearing upper shaft with a diameter matching the inner diameter of the bearing to be measured, and the bottom center of the tool lower cover is provided with a flange matching the mounting groove on the base, so that the tool lower cover is installed in the mounting groove of the base; the middle part of the tool spacer ring is recessed by a convex ring, so that the upper part and the lower part of the tool spacer ring each form a bearing installation groove matching the outer ring of the bearing to be measured; the bottom surface of the tool upper cover is provided with a bearing lower shaft with a diameter matching the inner diameter of the bearing to be measured, and the tool upper cover is coaxially connected to the bottom of the load transmission shaft; the bearing driving assembly comprises four roller supports fixed symmetrically on the peripheral top surface of the mounting groove of the base and located inside the four axial telescopic rods, a driving roller installed on one roller support and tangent to the middle part of the outer surface of the tool spacer ring, three driven rollers each installed on another three roller supports and tangent to the middle part of the outer surface of the tool spacer ring, and a roller driving motor installed on a support and drivingly connected to the driving roller; the force sensor is installed on the load transmission shaft of the axial loading assembly; two first distance sensors are each installed on the top surface of the base and the bottom surface of the top platform; two second distance sensors are each installed on the top surface of the tool lower cover and the bottom surface of the tool upper cover; the measurement controller is respectively connected in signal with the force sensor, the two first distance sensors, the two second distance sensors and the four electro-hydraulic rods.

2. The device for measuring the stiffness of a pair of main bearings of an RV reducer according to claim 1, characterized in that, the bottom of the load transmission shaft is connected to the tool upper cover through a pressure plate.

3. The device for measuring the stiffness of a pair of main bearings of an RV reducer according to claim 1, characterized in that, the roller driving motor of the bearing driving assembly is further connected to the driving roller through a gear transmission mechanism or a belt transmission mechanism.

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