Friction pair performance test device for space long-life conductive slip ring under vacuum conditions
Through the five-dimensional precision displacement stage and inductive dynamic torque sensor, dynamic torque sensing is performed in a vacuum environment, the accuracy of the dynamic contact characteristic test of the conductive slip ring friction pair is solved, and the precise test of the friction pair performance of the conductive slip ring is realized , improves the service life of the space conductive slip ring.
Patent Information
- Application Number
- CN201910185219.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2019-03-12
- Publication Date
- 2024-12-20
- Estimated Expiration
- 2039-03-12
AI Technical Summary
The prior art cannot truly reflect the dynamic contact characteristics of the conductive slip ring friction pair during rotation, and there is a difference between the friction and wear characteristic test and the actual state, so it is difficult to accurately test the friction and wear characteristics of the conductive slip ring friction pair, which affects its service life.
The five-dimensional precision displacement table is used to realize the pressure loading of brush wires, combined with DC brushless motor, planetary reducer and inductive dynamic torque sensor, dynamic torque sensing and precision displacement adjustment in vacuum environment to ensure the vacuum service life of the test device and Test accuracy.
Accurate testing of the friction pair performance of the conductive slip ring is achieved, ensuring that the test results are consistent with the actual state, and improving the service life of the space conductive slip ring and the reliability of the test device.
Smart Images
Figure CN109975150B_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to a precision testing instrument and relates to a space long-life conductive slip ring friction pair performance testing device. Background Art
[0002] Conductive slip rings are mainly composed of slip ring shaft system, conductive friction pair (brush wire, brush wire bundle, brush block and ring pair), brush holder, lead wire and other parts. They are components for realizing power or signal transmission between continuous rotating motion equipment. With the continuous development and progress of space science and technology, higher requirements are put forward for the service life of space conductive slip rings. The friction pair of conductive slip ring is the core component that determines the service life of conductive slip rings. Its friction and wear characteristics under the combined action of current loading and pressure loading in a vacuum environment are the key factors that determine the service life of space conductive slip rings.
[0003] At present, the method for testing the performance of space conductive slip ring friction pairs is mainly to use a vacuum friction and wear tester to test the friction and wear characteristics of friction pair materials. This test method ensures that the contact pressure remains unchanged during the test through a pressure loading device, and the friction coefficient test of conductive friction pair materials is very accurate. However, since the slip ring friction pair is a dynamic contact process when the slip ring rotates, the friction and wear characteristics and wear state under stable pressure cannot truly reflect the dynamic contact characteristics of the friction pair during the rotation process of the conductive slip ring. At the same time, in order to ensure the accuracy of pressure loading, this test method usually uses the end face of the ring instead of the circumferential surface of the ring to test the friction and wear characteristics, which is different from the actual state of the product.
[0004] Therefore, how to accurately test the friction and wear characteristics of the conductive slip ring friction pair, so as to promote the improvement of the service life of the space conductive slip ring, is a technical problem that needs to be solved urgently. Summary of the invention
[0005] In order to solve the technical problems that the prior art cannot truly reflect the dynamic contact characteristics of the friction pair during the rotation process of the conductive slip ring, and there is a difference between the friction and wear characteristics test data and the actual state of the product, and to more accurately test the friction and wear characteristics of the conductive slip ring friction pair, the present invention provides a space long-life conductive slip ring friction pair performance test device under vacuum conditions, which realizes brush wire (or bundle, block) pressure loading, dynamic torque sensing to collect friction torque, DC brushless motor and planetary reducer drive, vacuum lubrication treatment to ensure the vacuum service life of the device and other technical means through a five-dimensional precision displacement stage, thereby realizing precise performance testing of the space conductive slip ring friction pair, and providing a strong guarantee for the development of space conductive slip rings.
[0006] The technical solution of the present invention:
[0007] A space long-life conductive slip ring friction pair performance test device under vacuum conditions, wherein the friction pair to be tested includes a brush wire and a ring track; the special feature of the space conductive slip ring friction pair performance test device is that the space conductive slip ring friction pair performance test device includes a base plate, a DC brushless motor, a planetary reducer, an elastic coupling, an inductive dynamic torque sensor, a ring track retainer, a ring track gland, and a five-dimensional precision translation stage, which are sequentially arranged on the base plate;
[0008] The brushless DC motor, the planetary reducer, the elastic coupling, the inductive dynamic torque sensor, and the ring retainer are coaxially connected in sequence; the ring gland is used to fix the ring on the ring retainer;
[0009] A brush wire holder bracket is installed on the five-dimensional precision displacement platform, and a brush wire holder is installed on the brush wire holder bracket; the brush wire holder is used to clamp the brush wire;
[0010] The five-dimensional precision translation stage can adjust the position of the brush wire relative to the ring track through three translational degrees of freedom and two rotational degrees of freedom, so that the contact state between the brush wire and the ring track is consistent with the contact state between the brush wire and the ring track in the actual slip ring product.
[0011] Furthermore, it also includes a protective cover installed on the base plate, and a through hole is opened on the end face of the protective cover close to the five-dimensional precision displacement platform; the DC brushless motor, planetary reducer, elastic coupling and inductive dynamic torque sensor are all located in the protective cover, and one end of the main shaft of the inductive dynamic torque sensor passes through the through hole and then extends out of the protective cover; a labyrinth sealing cover is installed at the through hole.
[0012] Furthermore, there are multiple brush filament retainers, which are symmetrically or evenly distributed on the periphery of the side wall of the ring track retainer, and are used to symmetrically or evenly distribute the brush filaments outside the ring track.
[0013] Furthermore, each brush filament holder is used to symmetrically clamp two groups of brush filaments.
[0014] Furthermore, the brushless DC motor and the inductive dynamic torque sensor use a saturated vapor pressure ≤10 -9 Pa aerospace grease lubrication.
[0015] Furthermore, the resolution of the inductive torque sensor is less than 0.001 Nm.
[0016] Furthermore, the five-dimensional precision translation stage includes a displacement differential scale, and the accuracy of the displacement differential scale is at least 0.005 mm.
[0017] Beneficial effects of the present invention:
[0018] 1. The present invention fixes the brush holder on a five-dimensional precision displacement platform, uses the platform's multiple degrees of freedom to adjust the contact state of the pair, realizes pressure loading of the friction pair, and can effectively ensure the consistency of the contact state of the pair and the state of the slip ring product; at the same time, the displacement differential scale of the five-dimensional precision displacement platform can accurately record the current position, which is convenient for separating and checking the state of the pair during the performance test, and can ensure that the pair is accurately reset after the inspection.
[0019] 2. The present invention fixes the friction pair ring track retainer on an inductive high-precision dynamic torque sensor to directly measure the dynamic torque of the ring track during rotation, avoiding the error caused by measuring the tangential force of the paired pair and then converting it into the friction torque of the paired pair; at the same time, an inductive dynamic torque sensor is used as a torque test element in a vacuum environment to avoid its signal being transmitted through a conductive slip ring with limited vacuum life, which can effectively ensure the life and reliability of the entire device.
[0020] 3. The present invention adopts a brushless DC torque motor as a running-in structure driving element, which can achieve output under various speed conditions. At the same time, the brushless characteristics of this motor can avoid motor sparking, arcing and other phenomena in a vacuum environment, and has a long vacuum life. The driving torque can be amplified and output through a planetary reducer, and the motor vibration can be effectively isolated to avoid the vibration being directly transmitted to the sensor or product, affecting the test accuracy.
[0021] 4. The brush wire holder is symmetrically or evenly distributed on the periphery of the ring holder, so that the brush wire can be symmetrically or evenly distributed on the periphery of the ring, meeting the requirements of electrical performance test leads during the rotation of the friction pair, and overcoming the disadvantage of leading the test cable from the rotor, which limits the test range.
[0022] 5. The present invention performs vacuum lubrication treatment on moving components such as motors and sensors in the device, and uses aerospace grease with lower saturated vapor pressure to replace ordinary grease, thereby ensuring the vacuum service life of the test device.
[0023] 6. Vacuum condensable volatile pollution will seriously affect the conductive performance of the friction pair. The present invention has adopted effective protection measures against condensable volatile pollution. All non-metallic parts have been vacuum vented, and all moving parts are lubricated with low-volatile aerospace grease. At the same time, the test end and the product end are physically isolated by box seals (protective covers) and labyrinth seals in the structural design, which effectively prevents pollutants in the device from contaminating the friction pair.
[0024] 7. The displacement differential scale accuracy of the five-dimensional precision displacement platform is at least 0.005mm, which can accurately indicate the current position, facilitate the separation and inspection of the friction pair during the performance test, and ensure the accurate reset of the friction pair after inspection. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Figure 1It is a schematic diagram of the structural composition of the present invention.
[0026] Figure 2 It is a partial view of the present invention.
[0027] Figure 3 Schematic diagram of the friction pair of the conductive slip ring with a single brush retainer.
[0028] Figure 4 Schematic diagram of the friction pair of the conductive slip ring with double brush retainer.
[0029] Figure 5 Schematic diagram of a single brush holder.
[0030] Figure 6 Schematic diagram of a double brush holder.
[0031] Numbers in the figure:
[0032] 1-five-dimensional precision displacement platform; 2-brush holder bracket; 3-inductive dynamic torque sensor; 4-planetary reducer; 5-DC brushless motor; 6-protective cover; 7-reducer support; 8-elastic coupling; 9-sensor support; 10-base plate; 11-differential head; 12-ring cover; 13-ring retainer; 14-brush holder; 15-labyrinth seal cover; 16-brush; 17-ring. DETAILED DESCRIPTION
[0033] The present invention will be further described below in conjunction with the accompanying drawings.
[0034] See also Figure 1 , Figure 2 The space conductive slip ring friction pair performance testing device provided by the present invention includes a five-dimensional precision displacement platform 1, a brush holder bracket 2, an inductive dynamic torque sensor 3, a planetary reducer 4, a DC brushless torque motor 5, a protective cover 6, a reducer support 7, an elastic coupling 8, a sensor support 9, a base plate 10, a ring cover 12, a ring retainer 13, a brush holder 14, and a labyrinth seal cover 15.
[0035] Figure 3 , 4 The friction pair composed of the brush 16 and the ring 17 is the component to be tested.
[0036] The five-dimensional precision displacement platform 1 is fixedly mounted on the base plate 10, and the brush holder bracket 2 is mounted on the five-dimensional precision displacement platform 1. The five-dimensional precision displacement platform 1 can adjust the relative position of the brush 16 and the ring track 17 in the friction pair through three translational degrees of freedom: the displacement along the axial direction of the ring track 17 can adjust the centration of the ring track 17 and the brush 16, the displacement along the tangential direction of the ring track 17 can adjust the position of the contact point between the brush 16 and the ring track 17, and the displacement along the radial direction of the ring track 17 can adjust the deformation of the brush 16 and thus adjust the brush pressure; the five-dimensional precision displacement platform 1 can adjust the inclination between the brush 16 and the ring track 17 through two rotational degrees of freedom, which can eliminate the inclination error caused by the assembly process and effectively ensure the consistency between the contact state of the friction pair and the state of the slip ring product.
[0037] The displacement differential scale accuracy of the five-dimensional precision displacement platform 1 is 0.005mm, which can accurately indicate the current position, facilitate the separation and inspection status of the friction pair during the performance test, and ensure the accurate resetting of the friction pair after the inspection.
[0038] In order to truly simulate the actual installation state of the friction pair in the slip ring product, the present invention has multiple brush wire holders 14, which are symmetrically or evenly distributed around the ring track holder 13; the brush wire holder can be designed to be a structure capable of clamping a group of brush wires, such as Figure 5 As shown; the brush wire holder can also be designed to be able to clamp two sets of brush wires, such as Figure 6 As shown, such a design can meet the requirement of equipping a single ring track 17 with two or four brushes, so that two groups of brush wires 16 can be symmetrically or evenly distributed on the ring track 17 to form a friction pair, or four groups of brush wires 16 can be symmetrically or evenly distributed on the ring track 17 to form a friction pair. At the same time, the solution of multiple brush wire holders 14 symmetrically or evenly distributed on the periphery of the ring track holder 13 allows the brush wires to be symmetrically or evenly distributed on the periphery of the ring track 17, meeting the requirements of electrical performance test leads during the rotation of the friction pair, overcoming the disadvantage of limiting the test range by leading the test cable from the rotor. The aforementioned symmetrical distribution refers to symmetrical distribution relative to the center of the ring track 17.
[0039] Friction torque is also an important evaluation index of conductive slip rings. The friction torque of the friction pair and its change during its entire life are also the focus of friction pair performance testing. The inductive dynamic torque sensor 3 is fixed on the base plate 10 through the sensor support 9. The inductive dynamic torque sensor 3 is used to directly measure the dynamic torque of the friction pair during the relative rotation process, avoiding the error caused by the traditional measurement method of first measuring the tangential force of the friction pair and then converting it into the friction torque of the friction pair.
[0040] Since the basic value of the friction torque of a single friction pair is relatively small, at the level of 0.005Nm, the resolution of the inductive dynamic torque sensor 3 selected in the present invention is less than 0.001Nm; the inductive dynamic torque sensor 3 is used as a torque testing device under a vacuum environment, and its signal is transmitted through the sensing element of the inductive dynamic torque sensor 3 and the transmission shaft of the inductive dynamic torque sensor 3 to the acquisition card of the inductive dynamic torque sensor 3, thereby avoiding signal transmission through the conductive slip ring with limited vacuum life, and effectively ensuring the life and reliability of the entire friction pair performance testing device.
[0041] The brushless DC motor 5 is the driving element of the entire test device and is fixed at the tail end of the planetary reducer 4. The brushless DC motor selected in the present invention can achieve a speed output of 20 to 2000 rpm, and a torque output range of 0.02 to 0.15 Nm. Its brushless characteristics can avoid motor sparking and arcing in a vacuum environment. The speed setting of the brushless DC motor 5 is to cooperate with the reducer to achieve the friction pair speed 1 to 100 rpm test requirement. This speed range can basically cover the spatial application speed of this type of product; the torque value selection range of the brushless DC motor 5 is mainly based on the start-up friction torque and dynamic friction torque of the reducer.
[0042] The planetary reducer 4 is fixedly mounted on the bottom plate 10 through the reducer support 7. The reduction ratio of the planetary reducer 4 of the present invention is 1:20, and the driving torque output by the DC brushless motor 5 can be amplified and output. The planetary reducer 4 is connected to the inductive dynamic torque sensor 3 through an elastic coupling 8, and the elastic coupling 8 can effectively isolate the vibration generated during the operation of the DC brushless motor 5 to prevent the vibration from being transmitted to the inductive dynamic torque sensor 3 or the product to be tested, which affects the test accuracy.
[0043] In order to ensure that the friction pair performance test device can meet the vacuum use requirements, the present invention specially designs a corresponding lubrication scheme: the bearings in the moving components such as the DC brushless motor 5 and the inductive dynamic torque sensor 3 are vacuum lubricated. Considering that the friction pair performance test is a long process, aerospace-specific grease with a lower saturated vapor pressure is used instead of ordinary grease to ensure the vacuum service life of the friction pair performance test device.
[0044] Considering that the condensable volatile pollution in a vacuum environment will seriously affect the friction characteristics and conductive properties of the friction pair, the present invention adopts an effective condensable volatile pollution protection scheme: the DC brushless motor 5 and the inductive dynamic torque sensor 3 and other moving parts are lubricated with aerospace grease with a low saturated vapor pressure, and a protective cover 6 is installed on the bottom plate 10, and the DC brushless motor 5, the planetary reducer 4, the reducer support 7, the elastic coupling 8, the inductive dynamic torque sensor 3, and the sensor support 9 are arranged in the protective cover 6. The protective cover 6 is provided with a through hole on the end surface close to the five-dimensional precision displacement platform 1, and one end of the main shaft of the inductive dynamic torque sensor 3 is penetrated After passing through the through hole, the protective cover 6 is extended out, and a labyrinth sealing cover 15 is installed at the through hole for sealing, thereby realizing physical isolation protection; since the five-dimensional precision displacement platform 1 has fewer movements and is fixed during the friction pair performance test, the moving parts such as the lead screw guide and the differential head 11 of the displacement differential scale inside the five-dimensional precision displacement platform 1 are treated with oil-free treatment (i.e., no lubricating oil is applied) to completely eliminate the source of pollution; at the same time, all non-metallic parts in the friction pair performance device test, such as the motor winding package, the connecting motor, the torque sensor, the friction pair wires, etc., are vacuum vented to effectively avoid pollutants from contaminating the friction pair and affecting the friction pair performance test.
[0045] Principle of the invention:
[0046] The present invention can complete the friction and wear characteristics test of the conductive slip ring friction pair during the long-term running-in process in a vacuum environment at a set rotation speed. Its working principle is to use the five-dimensional precision displacement platform 1, the brush wire holder 14, the ring track holder 13 and other components to form a friction pair with the brush wire 16 and the ring track 17 to simulate the assembly state of the friction pair in the conductive slip ring; the driving assembly composed of the DC brushless motor 5 and the planetary reducer 4 is used to drive the main shaft of the inductive dynamic torque sensor 3 to rotate, and the main shaft of the inductive dynamic torque sensor 3 drives the ring track 17 in the friction pair to rotate, so as to collect and record the rotation speed and dynamic friction torque formed by the friction pair during the relative rotation process.
[0047] The technical indicators of each functional component of the present invention have been fully designed and analyzed. Compared with the prior art, the applicable test environment and friction pair simulation state of the present invention are closer to the technical state of the friction pair in the space conductive slip ring. The measurement methods of pressure, current loading mode and dynamic friction torque can more truly reflect the technical state of the friction pair in the whole life cycle of the slip ring product. The test data has important guiding value for the improvement of space conductive slip ring technology. The successful application of the device has laid a solid foundation for improving the life of space conductive slip rings.
Claims
1. A device for testing the performance of friction pairs of space long-life conductive slip rings under vacuum conditions, wherein the friction pairs to be tested include brush wires and ring tracks; the device is characterized in that: It includes a base plate, a brushless DC motor, a planetary reducer, an elastic coupling, an inductive dynamic torque sensor, a ring retainer, a ring gland and a five-dimensional precision displacement stage which are sequentially arranged on the base plate; The brushless DC motor, the planetary reducer, the elastic coupling, the inductive dynamic torque sensor, and the ring retainer are coaxially connected in sequence; the ring gland is used to fix the ring on the ring retainer; A brush holder bracket is installed on the five-dimensional precision displacement table, and a brush holder is installed on the brush holder bracket; The brush wire holder is used to clamp the brush wire; there are multiple brush wire holders, which are symmetrically or evenly distributed on the periphery of the side wall of the ring track holder, and are used to symmetrically or evenly distribute the brush wire outside the ring track; The five-dimensional precision translation stage can adjust the position of the brush wire relative to the ring track through three translational degrees of freedom and two rotational degrees of freedom, so that the contact state between the brush wire and the ring track is consistent with the contact state between the brush wire and the ring track in the actual slip ring product.
2. The device for testing the friction pair performance of a space long-life conductive slip ring under vacuum conditions according to claim 1, characterized in that: It also includes a protective cover installed on the base plate, and a through hole is opened on the end face of the protective cover close to the five-dimensional precision displacement platform; the DC brushless motor, planetary reducer, elastic coupling and inductive dynamic torque sensor are all located in the protective cover, and one end of the main shaft of the inductive dynamic torque sensor passes through the through hole and then extends out of the protective cover; a labyrinth sealing cover is installed at the through hole.
3. The device for testing the friction pair performance of a space long-life conductive slip ring under vacuum conditions according to claim 2, characterized in that: Each brush wire holder is used for symmetrically clamping two groups of brush wires.
4. The device for testing the friction pair performance of a space long-life conductive slip ring under vacuum conditions according to claim 3 is characterized in that: The DC brushless motor and inductive dynamic torque sensor use saturated vapor pressure ≤10 -9 Pa aerospace grease lubrication.
5. The device for testing the friction pair performance of a space long-life conductive slip ring under vacuum conditions according to claim 4 is characterized in that: The resolution of the inductive torque sensor is less than 0.001Nm.
6. The device for testing the friction pair performance of a space long-life conductive slip ring under vacuum conditions according to claim 5 is characterized in that: The five-dimensional precision translation stage includes a displacement differential scale, and the accuracy of the displacement differential scale is at least 0.005 mm.