CN115014762B

CN115014762B - Ultralow temperature vacuum bearing testing machine

Info

Publication number: CN115014762B
Application number: CN202210778383.XA
Authority: CN
Inventors: 陈宏展; 崔文岩; 马天宝
Original assignee: Tsinghua University
Current assignee: Tsinghua University
Priority date: 2022-07-04
Filing date: 2022-07-04
Publication date: 2023-06-30
Anticipated expiration: 2042-07-04
Also published as: CN115014762A

Abstract

The invention relates to an ultralow temperature vacuum bearing testing machine. The ultralow temperature vacuum bearing testing machine comprises: a support module; the vacuum module comprises a vacuum container and a vacuum pump set which are supported by the support module; the clamp module is arranged in the vacuum container and used for clamping the bearing test piece; the main shaft module comprises a main shaft and a driving mechanism, the main shaft penetrates through an inner ring of the bearing test piece, and the driving mechanism is positioned outside the vacuum container and supported by the supporting module; the inner ring refrigerating module is connected with one end of the main shaft, and one end of the inner ring refrigerating module, which is away from the main shaft, extends out of the vacuum container and is driven to rotate by the driving mechanism; the outer ring refrigerating module is arranged on the clamp module and used for refrigerating the clamp module; the loading module is used for loading the clamp module to load the bearing test piece; and the measuring module is arranged in the vacuum container and is used for measuring the friction moment of the bearing test piece. The ultralow temperature vacuum bearing test machine can realize the measurement of the friction moment of the bearing under special working conditions such as vacuum, low temperature and the like.

Description

Ultralow temperature vacuum bearing testing machine

Technical Field

The invention relates to the technical field of bearing test devices, in particular to an ultralow temperature vacuum bearing test machine.

Background

The bearing is a key element in the rotating mechanism, and has great challenges for realizing normal operation of the bearing under complex environments such as high vacuum space, large-span temperature change (-150 ℃ to 150 ℃), and the like.

Because the traditional oil/fat lubrication is difficult to meet the lubrication requirements of the space under the complex environments such as vacuum, low temperature, large-span temperature change and the like, and the solid lubrication overcomes the inherent defects of the oil/fat lubrication, the solid lubrication bearing is widely applied to space aircrafts such as deep space probes, space telescopes and the like.

However, at present, the performance test of friction moment and the like of the solid lubrication bearing under the special working conditions of vacuum, low temperature and the like is relatively lack, so that the mechanism researches of friction, abrasion, lubrication and the like of the solid lubrication bearing are not deep, and the performance of the solid lubrication bearing still needs to be improved.

Disclosure of Invention

Based on the above, it is necessary to provide an ultralow temperature vacuum bearing testing machine for testing the friction torque of the bearing under the special working conditions of vacuum, low temperature and the like, aiming at the problem that the performance test of the friction torque and the like of the solid lubrication bearing under the special working conditions of vacuum, low temperature and the like is lack in the prior art.

An ultra-low temperature vacuum bearing testing machine, comprising:

A support module;

the vacuum module comprises a vacuum container supported by the support module and a vacuum pump set connected with the vacuum container;

the clamp module is arranged in the vacuum container and used for clamping the outer ring of the bearing test piece;

the main shaft module comprises a main shaft and a driving mechanism, the main shaft penetrates through and is fixedly provided with an inner ring of the bearing test piece, and the driving mechanism is positioned outside the vacuum container and is supported by the supporting module;

the inner ring refrigerating module is connected with one end of the main shaft, and one end of the inner ring refrigerating module, which is away from the main shaft, extends out of the vacuum container and is driven to rotate by the driving mechanism;

the outer ring refrigerating module is arranged on the clamp module and used for refrigerating the clamp module;

the loading module is used for loading the clamp module to load the bearing test piece; a kind of electronic device with high-pressure air-conditioning system

And the measuring module is arranged in the vacuum container and is used for measuring the friction moment of the bearing test piece.

When the ultralow temperature vacuum bearing testing machine is used for carrying out friction torque testing on the bearing test piece, the clamp module clamps the outer ring of the bearing test piece. The main shaft is penetrated and fixed with an inner ring of the bearing test piece. The driving mechanism drives one end of the inner ring refrigerating module, which is away from the main shaft, to rotate, so that the inner ring refrigerating module drives the main shaft to rotate around the central axis of the main shaft, and further, the inner ring of the bearing test piece rotates relative to the outer ring of the bearing test piece, and friction torque is generated between the inner ring and the outer ring of the bearing test piece. The clamp module is loaded by the loading module so as to load the bearing test piece, so that the measuring module can measure the friction moment of the bearing test piece under different loads. Because the bearing test piece is arranged in the vacuum container, the vacuum container is vacuumized through the vacuum pump group, so that a vacuum working condition can be provided for friction torque measurement of the bearing test piece. Because the inner ring refrigerating module is connected with one end of the main shaft, the cold energy from the inner ring refrigerating module can be transmitted to the inner ring of the bearing test piece through the main shaft to cool the inner ring of the bearing test piece. The outer ring refrigerating module is arranged on the clamp module and used for refrigerating the clamp module, so that the cold from the outer ring refrigerating module can be transmitted to the outer ring of the bearing test piece through the clamp module, and the outer ring of the bearing test piece is cooled. The combined action of the inner ring refrigerating module and the outer ring refrigerating module enables the outer ring and the inner ring of the bearing test piece to be cooled simultaneously, so that the temperature uniformity between the outer ring and the inner ring is good, and further ideal ultralow temperature working conditions can be provided for the bearing test piece. Therefore, the ultralow temperature vacuum bearing test machine can realize the measurement of the friction moment of the bearing under the special working conditions of vacuum, low temperature and the like.

In one embodiment, the inner ring refrigeration module includes:

the cold guide chamber is arranged in the vacuum container and is connected with one end of the main shaft;

the hollow shaft is connected with one end of the cold guide chamber, which is far away from the main shaft, and is communicated with the cold guide chamber, one end of the hollow shaft, which is far away from the cold guide chamber, extends out of the vacuum container and is driven to rotate by the driving mechanism, one end of the hollow shaft, which extends out of the vacuum container, is sleeved with a pressure barrel, the pressure barrel is communicated with the hollow shaft, and the pressure barrel is used for being connected with an air extracting pump; a kind of electronic device with high-pressure air-conditioning system

The liquid nitrogen pipe penetrates through the hollow shaft, one end of the liquid nitrogen pipe extends out of the hollow shaft and extends into the cold guide chamber, and the other end of the liquid nitrogen pipe extends out of the hollow shaft and is used for being connected with a liquid nitrogen source;

the liquid nitrogen pipe is characterized in that a convex column is arranged at the bottom of the inner cavity of the cold conducting chamber, a through hole is formed in the convex column, two ends of the through hole are respectively communicated with the inner cavity of the cold conducting chamber and the hollow shaft, and one end of the liquid nitrogen pipe extends out of the through hole and extends out of the convex column in the radial direction.

In an embodiment, the inner ring refrigeration module further comprises a temperature sensor and a conductive slip ring, the conductive slip ring is arranged at one end of the hollow shaft extending out of the vacuum container, the temperature sensor is arranged in the cold conduction chamber, the temperature sensor is connected with the inner ring of the conductive slip ring through a temperature measurement wire penetrating through the hollow shaft, and the outer ring of the conductive slip ring is used for being connected to a measurement control system;

The ultralow temperature vacuum bearing testing machine further comprises an inner ring heating module, the inner ring heating module comprises an electric heating piece, the electric heating piece is arranged in the cold guide chamber, and the electric heating piece is connected with the inner ring of the conductive slip ring through a heating wire penetrating through the hollow shaft.

In an embodiment, the fixture module comprises a fixture main body and a fixture shell, wherein an annular groove is formed in the inner side wall of the fixture main body and used for being matched with the outer ring of the bearing test piece, and the fixture shell is sleeved and fixed outside the fixture main body.

In one embodiment, the clamp housing is provided with a liquid nitrogen channel;

the outer ring refrigeration module includes:

the liquid inlet pipe is connected with the clamp shell at one end and is communicated with the liquid nitrogen channel, and the other end of the liquid inlet pipe is connected to a true idle joint arranged on the vacuum container so as to be connected with a liquid nitrogen source outside the vacuum container;

one end of the exhaust pipe is connected with the clamp shell and is communicated with the liquid nitrogen channel, and the other end of the exhaust pipe is used for being connected to a true idle joint arranged on the vacuum container so as to be communicated with the outside of the vacuum container; and

The clamp module is provided with the temperature sensor, and the temperature sensor is used for being connected to a measurement control system through a vacuum cable connector arranged on the vacuum container;

the ultralow temperature vacuum bearing testing machine also comprises an outer ring heating module, wherein the outer ring heating module comprises an electric heating piece, the electric heating piece is arranged in the clamp shell, and the electric heating piece is connected to a measurement control system through a vacuum cable connector arranged on the vacuum container.

In an embodiment, the spindle module comprises a support bearing and a bearing seat, wherein the two ends of the spindle are respectively connected with the support bearing, and each support bearing is connected with the vacuum container through the corresponding bearing seat; the supporting bearing connected with one end of the main shaft, which is close to the inner ring refrigerating module, adopts a back-mounted angular contact bearing; the main shaft deviates from the support bearing connected with one end of the inner ring refrigerating module and adopts a cylindrical roller bearing.

In an embodiment, the number of the loading modules is two, one is a radial loading module for loading in the radial direction of the bearing test piece, and the other is an axial loading module for loading in the axial direction of the bearing test piece;

The loading module comprises an electromagnet, an armature and an electric cylinder, wherein the electromagnet is arranged in the vacuum container, the armature is connected with the clamp module, the output end of the electric cylinder is connected with the electromagnet, and the electric cylinder is used for driving the electromagnet to move towards a direction close to or far away from the armature.

In an embodiment, the electromagnet is disposed opposite to the armature, and a surface of the electromagnet facing the armature and a surface of the armature facing the electromagnet are both part spherical surfaces.

In an embodiment, the electromagnet comprises an inner magnet, a coil and an isolation shell, wherein the coil is wound on the outer side of the inner magnet, the inner magnet and the coil are both positioned in the isolation shell, one end of the inner magnet is opposite to the armature, and one end, close to the armature, of the isolation shell is in sealing connection with the inner magnet;

the loading module further comprises an adjusting corrugated pipe, the adjusting corrugated pipe is arranged on one side, deviating from the armature, of the isolating shell, one end of the adjusting corrugated pipe is in sealing connection with the isolating shell, the other end of the adjusting corrugated pipe is in sealing connection with the vacuum container, and the inner side of the adjusting corrugated pipe is communicated with the outer side of the vacuum container and the inner side of the isolating shell.

In one embodiment, the measurement module comprises:

one end of the force transfer beam is connected with the clamp module, and the other end of the force transfer beam extends to the radial outer side of the clamp module;

a sensor support portion provided to the vacuum vessel;

a force sensor provided to the sensor support portion;

one end of the pressure rod is fixedly connected with the force sensor; and

the other end of the pressure rod faces the force transfer beam and is fixedly connected with the force application ball;

the friction moment generated when the inner ring and the outer ring of the bearing test piece rotate relatively can enable the force transmission beam to rotate in the direction of extruding the force application ball.

Drawings

FIG. 1 is a schematic diagram of an embodiment of an ultra-low temperature vacuum bearing testing machine;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a cross-sectional view A-A of FIG. 2;

FIG. 4 is a cross-sectional view B-B of FIG. 2;

FIG. 5 is a schematic structural diagram of an inner ring refrigeration module of the ultralow temperature vacuum bearing testing machine of FIG. 1;

FIG. 6 is a schematic diagram of a spindle module of the ultra-low temperature vacuum bearing tester of FIG. 1;

FIG. 7 is a schematic diagram of a fixture module of the ultra-low temperature vacuum bearing tester of FIG. 1;

FIG. 8 is a schematic diagram of a driving mechanism of the ultra-low temperature vacuum bearing tester of FIG. 1;

FIG. 9 is a schematic diagram of a radial loading module of the ultra-low temperature vacuum bearing tester of FIG. 1;

FIG. 10 is a schematic diagram of an axial loading module of the ultra-low temperature vacuum bearing tester of FIG. 1;

FIG. 11 is a schematic diagram of a measurement module of the ultra-low temperature vacuum bearing testing machine of FIG. 1;

FIG. 12 is a force analysis schematic of the measurement module of FIG. 11 measuring friction torque of a bearing test piece;

fig. 13 is a schematic view of the ball rest assembly of fig. 11.

Reference numerals illustrate: an ultralow temperature vacuum bearing testing machine 1; a support module 10; a vacuum module 20; a vacuum vessel 21; a vacuum pump unit 22; a molecular pump 221; a magnetic fluid sealing device 23; a clamp module 30; a clamp body 31; an outer peripheral surface 310 of the jig main body 31; annular groove 301; a main body portion 311; an end cap portion 312; a clamp housing 32; a spindle module 40; a main shaft 41; a support bearing 42; a lower support bearing 421; an upper support bearing 422; a bearing block 43; a lower bearing block 431; a lower bearing support 4311; an upper bearing housing 432; an upper bearing housing support 4321; a heat insulating sleeve 44; an inner insulating sleeve 441; an outer insulating sleeve 442; a driving mechanism 45; a motor 451; a motor support plate 4511; a drive wheel 452; driven wheel 453; a tensioning wheel 454; an inner ring refrigeration module 50; a cold guide chamber 51; a lumen 510; a post 511; a through hole 512; hollow shaft 52; a transfer bellows 521; a liquid nitrogen pipe 53; a pressure barrel 54; an adapter flange 541; a conductive slip ring 55; an outer ring refrigeration module 60; a liquid inlet pipe 61; an exhaust pipe 62; a loading module 70; an electromagnet 71; an inner magnet 711; a coil 712; an isolation housing 713; armature 72; an electric cylinder 73; a load sensor 74; adjusting bellows 75; a connecting rod 76; a guide structure 77; a radial loading module 70a; radial electromagnet 71a; a radial inner magnet 711a; radial coil 712a; radial isolation housing 713a; radial armature 72a; a radial electric cylinder 73a; radial cylinder support 731a; a radial loading force sensor 74a; radially adjusting the bellows 75a; a radial connecting rod 76a; a radial guide structure 77a; an axial loading module 70b; an axial electromagnet 71b; an axial inner magnet 711b; an axial coil 712b; an axial isolation housing 713b; an axial armature 72b; an axial loading socket 721; an axial cylinder 73b; an axial cylinder supporting portion 731b; support posts 7311; bearing plates 7312; bearing cylinder mount 732; a compensating bellows 733; an axial loading force sensor 74b; an axial adjustment bellows 75b; an axial connecting rod 76b; an axial guide structure 77b; a guide post 771; a guide linear bearing 772; a measurement module 80; a transfer beam 81; a force sensor 82; a sensor support 821; a sensor adaptation station 822; a pressure lever 83; a pressure bar adapter 831; a ball rest assembly 84; a ball rest chassis 841; ball-rest screw 842; a force application ball 85; a counterweight 86; a bearing test piece 2; an inner ring 2b; an outer ring 2a.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the device or element being referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present invention.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1 to 12, an embodiment of the present application provides an ultralow temperature vacuum bearing testing machine 1. The ultralow temperature vacuum bearing testing machine 1 is used for measuring friction moment of the bearing test piece 2 under special working conditions such as vacuum, low temperature and the like. The ultra-low temperature vacuum bearing testing machine 1 comprises: support module 10, vacuum module 20, clamp module 30, spindle module 40, inner race cooling module 50, outer race cooling module 60, loading module 70, and measurement module 80.

The vacuum module 20 includes a vacuum vessel 21 supported by the support module 10 and a vacuum pump unit 22 connected to the vacuum vessel 21. The clamp module 30 is provided in the vacuum vessel 21 and is used to clamp the outer race 2a of the bearing test piece 2. The spindle module 40 includes a spindle 41 and a drive mechanism 45. The main shaft 41 is penetrated and fixed with the inner ring 2b of the bearing test piece 2, and the driving mechanism 45 is positioned outside the vacuum container 21 and supported by the support module 10. The inner ring cooling module 50 is connected to one end of the main shaft 41. The end of the inner ring refrigeration module 50 facing away from the main shaft 41 extends out of the vacuum container 21 and is driven to rotate by the driving mechanism 45. The outer ring refrigeration module 60 is provided to the clamp module 30 and is used for refrigerating the clamp module 30. The loading module 70 is used to load the clamp module 30 to load the bearing test piece 2. The measuring module 80 is arranged in the vacuum vessel 21 and is used for measuring the friction torque of the bearing test piece 2.

When the ultralow temperature vacuum bearing testing machine 1 performs friction torque testing on the bearing test piece 2, the clamp module 30 clamps the outer ring 2a of the bearing test piece 2. The main shaft 41 is inserted through and fixed with the inner ring 2b of the bearing test piece 2. The driving mechanism 45 drives one end of the inner ring refrigerating module 50, which is away from the main shaft 41, to rotate, so that the inner ring refrigerating module 50 drives the main shaft 41 to jointly rotate around the central axis of the main shaft 41, and then the inner ring 2b of the bearing test piece 2 rotates relative to the outer ring 2a of the bearing test piece 2, and friction torque is generated between the inner ring and the outer ring. The clamp module 30 is loaded by the loading module 70 so as to load the bearing test piece 2, so that the measuring module 80 can measure the friction moment of the bearing test piece 2 under different loads. Because the bearing test piece 2 is arranged in the vacuum container 21, the vacuum pump set 22 is used for vacuumizing the vacuum container 21, so that a vacuum working condition can be provided for friction torque measurement of the bearing test piece 2. Since the inner ring cooling module 50 is connected to one end of the main shaft 41, the cooling capacity from the inner ring cooling module 50 can be transferred to the inner ring 2b of the bearing test piece 2 via the main shaft 41, and the inner ring 2b of the bearing test piece 2 is cooled. The outer ring refrigerating module 60 is arranged on the clamp module 30 and is used for refrigerating the clamp module 30, so that the cold from the outer ring refrigerating module 60 can be transmitted to the outer ring 2a of the bearing test piece 2 through the clamp module 30 to cool the outer ring 2a of the bearing test piece 2. The combined action of the inner ring refrigeration module 50 and the outer ring refrigeration module 60 enables the outer ring 2a and the inner ring 2b of the bearing test piece 2 to be cooled simultaneously, so that the temperature uniformity between the outer ring 2a and the inner ring 2b is good, and further ideal ultralow temperature working conditions can be provided for the bearing test piece 2. Therefore, the ultralow temperature vacuum bearing testing machine 1 can realize the measurement of the friction moment of the bearing under the special working conditions of vacuum, low temperature and the like.

As shown in fig. 1, 3 and 4, in the present embodiment, the support module 10 includes a plurality of square tubes connected to each other.

The bearing test piece 2 may be a rolling bearing, a knuckle bearing, or the like. It should be noted that the bearing test piece 2 is a solid lubrication bearing.

Referring to fig. 5 and 6, in an embodiment, the inner ring refrigeration module 50 includes a cold guide chamber 51, a hollow shaft 52, and a liquid nitrogen pipe 53. The cooling chamber 51 is provided in the vacuum vessel 21. The cold guide chamber 51 is connected between the main shaft 41 and the hollow shaft 52 and is communicated with the hollow shaft 52, and one end of the hollow shaft 52, which is away from the cold guide chamber 51, extends out of the vacuum container 21 and is driven to rotate by the driving mechanism 45. The liquid nitrogen pipe 53 is provided through the hollow shaft 52, and has one end extending out of the hollow shaft 52 and into the cold guide chamber 51 and the other end extending out of the hollow shaft 52 and being used for connection with a liquid nitrogen source (not shown).

Specifically, in fig. 5, the upper end of the cooling chamber 51 is connected to the lower end of the main shaft 41, and the lower end of the cooling chamber 51 is connected to and communicates with the upper end of the hollow shaft 52. The hollow shaft 52 has an upper end positioned inside the vacuum vessel 21 and a lower end extending outside the vacuum vessel 21. Referring to fig. 6, a liquid nitrogen pipe 53 is inserted into the hollow shaft 52, the upper end of the liquid nitrogen pipe 53 extends out of the upper end of the hollow shaft 52 and into the inner cavity 510 of the cold guide chamber 51, and the lower end of the liquid nitrogen pipe 53 extends out of the lower end of the hollow shaft 52 and is used for connecting a liquid nitrogen source.

Liquid nitrogen is introduced into the liquid nitrogen pipe 53 through a liquid nitrogen source, then the liquid nitrogen flows into the inner cavity 510 of the cold guide chamber 51 through the liquid nitrogen pipe 53, and cold energy from the liquid nitrogen is transmitted to the inner ring 2b of the bearing test piece 2 through the cold guide chamber 51 and the main shaft 41 in sequence, so that the inner ring 2b of the bearing test piece 2 can be cooled. Nitrogen formed by gasification after the liquid nitrogen is refrigerated enters the hollow shaft 52 through the communication part of the cold guide chamber 51 and the hollow shaft 52 and is discharged from the hollow shaft 52 to the outside of the vacuum container 21.

Referring to fig. 6, in an embodiment, a cavity bottom of an inner cavity 510 of the cold conducting chamber 51 is provided with a convex column 511, the convex column 511 is provided with a through hole 512, two ends of the through hole 512 are respectively communicated with the inner cavity 510 of the cold conducting chamber 51 and the hollow shaft 52, and one end of the liquid nitrogen pipe 53 extends out of the through hole 512 and extends out to the radial outer side of the convex column 511.

Specifically, the boss 511 protrudes upward from the bottom of the inner cavity 510. The upper end of the through hole 512 is in communication with the inner cavity 510. The lower end of the through hole 512 is in communication with the hollow shaft 52. The upper end of the liquid nitrogen pipe 53 extends out of the upper end of the through hole 512 and extends out to the radial outside of the convex column 511, so that the upper end of the liquid nitrogen pipe 53 extends into the inner cavity 510, and liquid nitrogen from the liquid nitrogen pipe 53 is accumulated at the bottom of the inner cavity 510 due to the action of gravity when entering the inner cavity 510 of the cold guide chamber 51. Since the convex column 511 protrudes upward from the bottom of the inner cavity 510, when the liquid level of the liquid nitrogen accumulated at the bottom of the cavity is not higher than the convex column 511, the convex column 511 can prevent the liquid nitrogen from flowing into the hollow shaft 52 from the inner cavity 510, and further can ensure the effective utilization of the liquid nitrogen. Nitrogen gas formed after gasification of the liquid nitrogen can then enter the hollow shaft 52 through the through hole 512 to be discharged through the hollow shaft 52.

Referring to fig. 5, in an embodiment, the inner ring refrigeration module 50 further includes a transfer bellows 521. The adapting corrugated pipe 521 is connected between the cold guide chamber 51 and the hollow shaft 52 for compensating the assembly error between the hollow shaft 52 and the cold guide chamber 51.

Referring to fig. 5, in one embodiment, an end of the hollow shaft 52 extending out of the vacuum container 21 is rotatably connected to the support module 10 through a bearing, so that the support module 10 can be supported, and the rotation process of the hollow shaft 52 is stable.

Referring to fig. 5, in one embodiment, a pressure vessel 54 is sleeved on an end of the hollow shaft 52 extending out of the vacuum vessel 21. The interior of hollow shaft 52 communicates with the interior cavity of pressure barrel 54. The pressure tank 54 is for connection to a suction pump (not shown). The interior of the pressure barrel 54 is pumped by the air pump, so that negative pressure is formed in the pressure barrel 54 and the hollow shaft 52, and then nitrogen gasified by liquid nitrogen in the cold guide chamber 51 is pumped out through the hollow shaft 52 and the pressure barrel 54 quickly, and is discharged.

As shown in fig. 5, in one embodiment, the sidewall of the pressure tank 54 is provided with an adapter flange 541, and the adapter flange 541 is used to connect with the pump, so as to facilitate the connection of the pump with the pressure tank 54.

In one embodiment, the source of liquid nitrogen to which liquid nitrogen tube 53 is connected is a liquid nitrogen barrel that is open to the atmosphere. When the air pump pumps air in the pressure barrel 54, the hollow shaft 52 and the cold guide chamber 51 are all negative pressure, so that the atmospheric pressure enables liquid nitrogen in the liquid nitrogen barrel to be pressed into the liquid nitrogen pipe 53 and the liquid nitrogen pipe 53 to be pressed into the cold guide chamber 51.

Referring to fig. 5, in one embodiment, the inner ring refrigeration module 50 further includes a temperature sensor (not shown) and an electrically conductive slip ring 55. An electrically conductive slip ring 55 is provided at the end of the hollow shaft 52 that protrudes from the vacuum vessel 21. Any one or more of the cold guide chamber 51, the main shaft 41 and the inner ring 2b of the bearing test piece 2 is/are provided with a temperature sensor, the temperature sensor is connected with the inner ring of the conductive slip ring 55 through a temperature measuring wire penetrating through the hollow shaft 52, the outer ring of the conductive slip ring 55 is connected to a measurement control system, so that temperature data measured by the temperature sensor can be transmitted to the measurement control system, and the refrigerating effect of the inner ring refrigerating module 50 can be conveniently controlled according to the temperature data measured by the temperature sensor. The inner ring and the outer ring of the conductive slip ring 55 can rotate relatively, so that when the cold guide chamber 51, the main shaft 41 and the inner ring 2b of the bearing test piece 2 rotate, the conductive slip ring 55 and the temperature measuring wire rotate together, and the temperature measuring wire cannot be wound and twisted.

In one embodiment, the ultra-low temperature vacuum bearing testing machine 1 further includes an inner ring heating module (not shown) disposed at an end of the inner ring cooling module 50 connected to the spindle 41. The inner ring heating module is used for heating the inner ring refrigerating module 50, so that the main shaft 41 is heated and the inner ring 2b of the bearing test piece 2 is heated through heat transfer among the inner ring refrigerating module 50, the main shaft 41 and the inner ring 2b of the bearing test piece 2, and further the temperature change range of the inner ring 2b of the bearing test piece 2 is wider, namely, the working condition of wide temperature range is provided for friction torque measurement of the bearing test piece 2.

Referring to fig. 5, in an embodiment, the inner ring heating module includes an electric heating element (not shown) disposed in the cold guide chamber 51. The electric heating element is connected with the inner ring of the conductive slip ring 55 through a heating wire penetrating through the hollow shaft 52, and the outer ring of the conductive slip ring 55 is connected to a measurement control system, so that the heating effect of the electric heating element can be controlled through the measurement control system. The inner ring and the outer ring of the conductive slip ring 55 can rotate relatively, so that when the hollow shaft 52 rotates, the heating wire and the inner ring of the conductive slip ring 55 rotate together, and the heating wire cannot be wound and twisted.

The electric heating member may be attached to the inner surface of the cooling chamber 51. Examples of the electric heating element include an electric heating plate, an electric heating rod, and an electric heating tube.

Referring to fig. 6 and 7, in one embodiment, the clamp module 30 includes a clamp body 31 and a clamp housing 32. The inner side wall of the clamp body 31 is provided with an annular groove 301. The annular groove 301 is for engagement with the outer ring 2a of the bearing test piece 2. The clamp housing 32 is sleeved outside the clamp body 31 and fixedly connected with the clamp body 31.

Specifically, the bearing test piece 2 is located in the holder body 31, and the outer ring 2a of the bearing test piece 2 is disposed in the annular groove 301, so that the groove walls of the annular groove 301 sandwich the outer ring 2a of the bearing test piece 2 from the radial direction and the axial direction, respectively.

Referring to fig. 7, in one embodiment, the outer peripheral surface 310 of the clamp body 31 is tapered to facilitate loading of the clamp body 31 into the clamp housing 32 and removal of the clamp body 31 from the clamp housing 32.

Referring to fig. 7, in one embodiment, the clamp body 31 includes a body portion 311 and an end cap portion 312 that are axially disposed and fixedly connected, the body portion 311 and the end cap portion 312 collectively enclosing the annular groove 301. In the assembly, the bearing test piece 2 may be first installed into the main body portion 311, and then the end cap portion 312 is abutted against the outer ring 2a of the bearing test piece 2 and the main body portion 311 is fixedly connected with the end cap portion 312, at this time, the groove wall of the annular groove 301 clamps the outer ring 2a of the bearing test piece 2. It can be seen that, in the present embodiment, the annular groove 301 is defined by the main body portion 311 and the end cap portion 312 together, and the end cap portion 312 can be pressed against the outer ring 2a of the bearing piece 2 at the time of assembly, thereby facilitating assembly and enabling the clamp main body 31 to reliably clamp the bearing piece 2.

In one embodiment, a liquid nitrogen passage (not shown) is provided within the clamp housing 32. Referring to fig. 6, the outer ring refrigeration module 60 includes a liquid inlet pipe 61 and an exhaust pipe 62. One end of the liquid inlet pipe 61 is connected to the clamp housing 32 and communicates with the liquid nitrogen passage, and the other end of the liquid inlet pipe 61 is adapted to be connected to a vacuum adapter (not shown) provided on the vacuum vessel 21 so as to be connected to a liquid nitrogen source (not shown) outside the vacuum vessel 21. One end of the exhaust pipe 62 is connected to the clamp housing 32 and communicates with the liquid nitrogen passage, and the other end of the exhaust pipe 62 is adapted to be connected to a vacuum adapter (not shown) provided on the vacuum vessel 21 so as to communicate with the outside of the vacuum vessel 21.

Liquid nitrogen from a liquid nitrogen source enters a liquid nitrogen channel in the clamp shell 32 through the liquid inlet pipe 61, so that cold energy from the liquid nitrogen is transmitted to the outer ring 2a of the bearing test piece 2 through the clamp shell 32 and the clamp body 31 to cool the outer ring 2a of the bearing test piece 2. The nitrogen gas formed by the vaporization of the liquid nitrogen in the liquid nitrogen passage after the liquid nitrogen is cooled is discharged to the outside of the vacuum vessel 21 through the gas discharge pipe 62.

In one embodiment, the other end of the exhaust pipe 62 is connected to an air pump (not shown) through a vacuum connection provided on the vacuum vessel 21. The air is pumped by the air pump, so that negative pressure is formed in the air exhaust pipe 62 and the liquid nitrogen channel, and then nitrogen gasified by liquid nitrogen in the liquid nitrogen channel is pumped away through the air exhaust pipe 62 rapidly to be exhausted.

In one embodiment, the liquid nitrogen source to which liquid inlet tube 61 is connected is a liquid nitrogen barrel that is open to the atmosphere. When the air pump pumps air in the exhaust pipe 62, negative pressure is arranged in the liquid nitrogen channel, so that the atmospheric pressure enables the liquid nitrogen in the liquid nitrogen barrel to be pressed into the liquid inlet pipe 61 and pressed into the liquid nitrogen channel from the liquid inlet pipe 61.

In one embodiment, the outer race refrigeration module 60 also includes a temperature sensor (not shown). Any one or more of the fixture module 30 and the outer ring 2a of the bearing test piece 2 is/are provided with a temperature sensor, and the temperature sensor is connected to an external measurement control system through a vacuum cable connector (not shown) arranged on the vacuum container 21, so that temperature data measured by the temperature sensor can be transmitted to the measurement control system, and the refrigerating effect of the outer ring refrigerating module 60 can be conveniently controlled according to the temperature data measured by the temperature sensor.

In one embodiment, the ultra-low temperature vacuum bearing tester 1 further includes an outer ring heating module (not shown) disposed on the fixture housing 32. The outer ring heating module is used for heating the clamp shell 32, so that the outer ring 2a of the bearing test piece 2 can be heated through heat transfer among the clamp shell 32, the clamp main body 31 and the outer ring 2a of the bearing test piece 2, and further the temperature change range of the outer ring 2a of the bearing test piece 2 is wider, namely, the working condition of wide temperature range is provided for friction torque measurement of the bearing test piece 2.

In one embodiment, the outer ring heating module includes an electrical heater. The electrical heating element is disposed within the clamp housing 32. The electric heating element is connected to an external measurement control system through a vacuum cable joint (not shown) provided on the vacuum vessel 21, so that the heating effect of the electric heating element can be controlled by the measurement control system.

An electrical heating element may be attached to the inner surface of the clamp housing 32. Examples of the electric heating element include an electric heating plate, an electric heating rod, and an electric heating tube.

Referring to fig. 1 and 2, in one embodiment, the vacuum pump unit 22 includes a molecular pump 221 and a mechanical pump (not shown), the molecular pump 221 is connected to the vacuum vessel 21, and the mechanical pump is connected to the molecular pump 221. The vacuum container 21 can be pumped with high vacuum through the mechanical pump and the molecular pump 221, so that a vacuum working condition is provided for friction torque measurement of the bearing test piece 2.

In one embodiment, a vacuum gauge (not shown) is provided on the vacuum vessel 21 for measuring the degree of vacuum in the vacuum vessel 21. Based on the measurement result of the vacuum gauge, it can be determined whether the vacuum degree in the vacuum vessel 21 satisfies the test requirement.

The vacuum gauge is connected to a measurement control system outside the vacuum container 21 in a wired connection manner, and the measurement control system can control the vacuumizing degree of the vacuum pump set 22 to the vacuum container 21 according to the measurement result of the vacuum gauge, so that the vacuum degree in the vacuum container 21 meets the test requirement.

Referring to fig. 1 to 5, in an embodiment, the vacuum module 20 further includes a magnetic fluid sealing device 23. The magnetic fluid sealing device 23 is disposed at the connection between the vacuum container 21 and the inner ring refrigeration module 50, and is used for realizing dynamic sealing at the connection between the vacuum container 21 and the inner ring refrigeration module 50, so as to maintain good vacuum degree in the vacuum container 21.

In particular, in the present embodiment, the magnetic fluid sealing device 23 is disposed at the connection between the vacuum container 21 and the hollow shaft 52, for realizing dynamic sealing at the connection between the vacuum container 21 and the hollow shaft 52.

In an embodiment, a nitrogen interface (not shown) is provided on the vacuum container 21, and after the vacuum container 21 is vacuumized, nitrogen can be filled into the vacuum container 21 through the nitrogen interface, so as to provide a nitrogen atmosphere for friction torque measurement of the bearing test piece 2.

In an embodiment, when bearing test pieces 2 with different width specifications are tested, only the shaft sleeves at two ends of the bearing test piece 2 are required to be replaced; when testing bearing test pieces 2 having different inner and outer diameters, it is necessary to replace the spindle 41 and the jig module 30 for testing.

Referring to fig. 6, in one embodiment, the spindle module 40 further includes a support bearing 42 and a bearing seat 43. The support bearings 42 are connected to both ends of the main shaft 41. Each support bearing 42 is connected to the vacuum vessel 21 by a corresponding bearing mount 43. Since the two ends of the main shaft 41 are respectively supported by the support bearings 42, circumferential runout of the two ends of the main shaft 41 during rotation can be reduced as much as possible, and the measurement stability of friction torque can be improved.

Referring to fig. 6, in an embodiment, the support bearing 42 connected to the end (i.e. the lower end) of the main shaft 41 near the cold guide chamber 51 is a lower support bearing 421, which is a back-mounted angular contact bearing. Therefore, the position of the main shaft 41 in the axial direction near one end (i.e., the lower end) of the cooling chamber 51 is fixed, so that the position is stable when the main shaft 41 rotates.

Referring to fig. 6, in an embodiment, the bearing seat 43 connected to the lower support bearing 421 is a lower bearing seat 431. The lower bearing mount 431 is supported by the lower bearing mount support part 4311 and connected to the vacuum vessel 21. The lower bearing housing support 4311 may be provided at the bottom of the vacuum vessel 21.

Referring to fig. 6, in one embodiment, the support bearing 42 to which an end (i.e., an upper end) of the main shaft 41 facing away from the cooling chamber 51 is connected is an upper support bearing 422, which employs a cylindrical roller bearing. Accordingly, the axial position of the end (i.e., the upper end) of the main shaft 41 facing away from the cooling chamber 51 is floatable, so that it is possible to compensate for the axial deformation of the main shaft 41 due to the temperature change.

Referring to fig. 6 in combination with fig. 3 and 4, in one embodiment, the bearing housing 43 to which the upper support bearing 422 is connected is an upper bearing housing 432. The upper bearing housing 432 is supported by the upper bearing housing support part 4321 and connected to the vacuum vessel 21. The upper bearing housing support 4321 may be provided at the bottom of the vacuum vessel 21.

Referring to fig. 6, in an embodiment, a heat insulation sleeve 44 is sleeved on the main shaft 41 to reduce heat leakage of the main shaft 41.

Referring to fig. 6, in an embodiment, an inner insulation sleeve 441 is disposed between the main shaft 41 and the inner ring of the lower support bearing 421 for reducing heat leakage between the main shaft 41 and the inner ring of the lower support bearing 421.

Referring to fig. 6, in an embodiment, an outer insulation sleeve 442 is disposed between the outer ring of the lower support bearing 421 and the lower bearing seat 431 for reducing heat leakage between the outer ring of the lower support bearing 421 and the lower bearing seat 431.

Referring to fig. 8, in one embodiment, the drive mechanism 45 includes a motor 451 and a synchronous pulley mechanism. The timing pulley mechanism includes a driving pulley 452 and a driven pulley 453 and a timing belt (not shown). The timing belt is wound around and tensioned to the driving pulley 452 and the driven pulley 453. An output shaft of the motor 451 is coaxially connected with the driving wheel 452. Driven wheel 453 is coaxially coupled with hollow shaft 52. The motor 451 drives the driving wheel 452 to rotate, so that the synchronous belt drives the driven wheel 453 to rotate, and the driven wheel 453 and the hollow shaft 52 coaxially rotate.

Referring to fig. 8, in an embodiment, the driving mechanism 45 further includes a tensioning wheel 454, and the tensioning wheel 454 is matched with the synchronous belt for tensioning the synchronous belt.

Referring to fig. 8, in an embodiment, the driving mechanism 45 further includes a motor support plate 4511. The motor support plate 4511 is fixed to the support module 10. The motor 451 is mounted on the motor support plate 4511.

Referring to fig. 8, in one embodiment, the end of the hollow shaft 52 extending out of the vacuum vessel 21 is rotatably connected to the motor support plate 4511 via a bearing, and thus indirectly rotatably connected to the support module 10.

Referring to fig. 3, 4, 9 and 10, in one embodiment, the loading module 70 includes: electromagnet 71 and armature 72. The electromagnet 71 is provided in the vacuum vessel 21. Armature 72 is coupled to clamp module 30. When the electromagnet 71 is energized, a magnetic force is generated that attracts the armature 72, so that the clamp module 30 can be acted upon by the magnetic force between the electromagnet 71 and the armature 72, and thus the bearing test piece 2. The electromagnet 71 loses its magnetic force when it is de-energized, so that the bearing test piece 2 can be unloaded.

The bearing test piece 2 is loaded by the magnetic force between the electromagnet 71 and the armature 72, and the electromagnet 71 and the armature 72 can be out of contact, so that non-contact loading can be realized, and measurement errors caused by loading are avoided.

The loading module 70 may be a radial loading module 70a for radially loading the bearing piece 2 or an axial loading module 70b for axially loading the bearing piece 2.

In one embodiment, both the surface of electromagnet 71 facing armature 72 and the surface of armature 72 facing electromagnet 71 are part spherical, so that when electromagnet 71 and armature 72 are assembled, the two opposite parts of spherical surfaces can be self-calibrated to compensate for deflection problems caused by machining and assembly.

Referring to fig. 3, 4, 9 and 10, in an embodiment, the loading module 70 further includes an electric cylinder 73, an output end of the electric cylinder 73 is connected to the electromagnet 71, and the electric cylinder 73 is used for driving the electromagnet 71 to move so as to adjust a magnetic gap between the electromagnet 71 and the armature 72, so that a magnetic force between the electromagnet 71 and the armature 72 can be adjusted, and thus, a load applied to the bearing test piece 2 can be adjusted.

In addition, the magnetic force between the electromagnet 71 and the armature 72 can be adjusted by adjusting the magnitude of the current when the electromagnet 71 is energized, thereby adjusting the magnitude of the load applied to the bearing piece 2.

Moreover, since the magnetic force between electromagnet 71 and armature 72 is adjusted by adjusting the magnitude of the current when electromagnet 71 is energized, loading of heavy loads can be achieved by supplying a larger current.

By adjusting the current level at which electromagnet 71 is energized and/or the magnetic gap between electromagnet 71 and armature 72, a stepless load change at the time of loading bearing test piece 2 can be achieved.

Referring to fig. 3, 4, 9 and 10, in one embodiment, electromagnet 71 includes an inner magnet 711, a coil 712 and an isolation housing 713. The coil 712 is wound outside the inner magnet 711. The inner magnet 711 and coil 712 are both located within the isolation housing 713. One end of inner magnet 711 is disposed opposite armature 72 such that magnetic force is generated between inner magnet 711 and armature 72 when coil 712 is energized. An end of isolation housing 713 adjacent armature 72 is sealingly connected to inner magnet 711. The end of isolation housing 713 facing away from armature 72 is sealingly connected to vacuum vessel 21, and the inside of isolation housing 713 communicates with the outside of vacuum vessel 21.

Since the inner magnet 711 and the coil 712 are both located in the isolation housing 713, the inside of the isolation housing 713 communicates with the outside of the vacuum vessel 21, so that heat generated by the coil 712 when the electromagnet 71 operates can be emitted to the atmosphere outside the vacuum vessel 21. Since the end of isolation housing 713 adjacent armature 72 is sealingly connected to inner magnet 711, the end of isolation housing 713 facing away from armature 72 is sealingly connected to vacuum vessel 21, thereby maintaining a vacuum environment within vacuum vessel 21.

In one embodiment, the loading module 70 further includes an adjustment bellows 75. An adjusting bellows 75 is provided on the side of isolation housing 713 facing away from armature 72. One end of the adjusting bellows 75 is connected with the isolation housing 713 in a sealed manner, the other end of the adjusting bellows 75 is connected with the vacuum vessel 21 in a sealed manner, and the inside of the adjusting bellows 75 is communicated with the outside of the vacuum vessel 21.

Since the other end of the regulating bellows 75 communicates with the outside of the vacuum vessel 21, heat generated by the coil 712 when the electromagnet 71 is operated can be emitted to the atmosphere outside the vacuum vessel 21 through the insulating housing 713 and the regulating bellows 75. Since one end of the adjustment bellows 75 is hermetically connected to the isolation housing 713, the other end of the adjustment bellows 75 is hermetically connected to the vacuum vessel 21, and thus the vacuum environment can be maintained in the vacuum vessel 21.

Further, by providing the adjustment bellows 75 between the vacuum chamber 21 and the electromagnet 71, the telescopic characteristic of the adjustment bellows 75 allows the electromagnet 71 to move relative to the vacuum chamber 21, and thus the magnetic gap between the electromagnet 71 and the armature 72 can be adjusted.

Referring to fig. 3, 4, 9 and 10, in one embodiment, the loading module 70 further includes a loading force sensor 74. The load force sensor 74 is connected between the electric cylinder 73 and the electromagnet 71, so that the load force sensor 74 can detect the magnitude of the magnetic force between the electromagnet 71 and the armature 72, and further can obtain the magnitude of the load force on the bearing test piece 2.

Referring to fig. 3, 4, 9 and 10, in one embodiment, the loading module 70 further includes a connecting rod 76. One end of the connecting rod 76 is connected to the electromagnet 71, and the other end extends outside the vacuum vessel 21 and is connected to the output end of the electric cylinder 73, thereby facilitating connection of the electromagnet 71 to the output end of the electric cylinder 73. In the present embodiment, a load force sensor 74 is connected between the electric cylinder 73 and a connecting rod 76.

Referring to fig. 3, 4, 9 and 10, in one embodiment, the loading module 70 further includes a guiding structure 77. The guide structure 77 serves to guide the moving direction of the electromagnet 71, thereby ensuring the loading direction to be accurate.

Referring to fig. 3, 4, 9 and 10, in one embodiment, the number of loading modules 70 is two, one is a radial loading module 70a and the other is an axial loading module 70b, so as to realize combined loading of the bearing test piece 2 in the radial and axial directions.

Referring to fig. 3, 4 and 9, in one embodiment, the radial loading module 70a includes: radial electromagnet 71a and radial armature 72a. The radial electromagnet 71a is provided in the vacuum chamber 21. Radial armature 72a is located radially outward of clamp module 30 and is connected to clamp module 30. When the radial electromagnet 71a is energized, a magnetic force is generated that attracts the radial armature 72a, so that the clamp module 30 can be acted upon in the radial direction by the magnetic force between the radial electromagnet 71a and the radial armature 72a, and thus the bearing test piece 2 in the radial direction. The radial electromagnet 71a loses its magnetic force when it is deenergized, so that the bearing test piece 2 can be unloaded.

In one embodiment, the surface of radial electromagnet 71a facing radial armature 72a and the surface of radial armature 72a facing radial electromagnet 71a are both part-spherical, so that when radial electromagnet 71a and radial armature 72a are assembled, the two opposite part-spherical surfaces can be self-calibrated to compensate for deflection problems caused by machining, assembly and the like.

Referring to fig. 3, 4 and 9, in an embodiment, the radial loading module 70a further includes a radial cylinder 73a, an output end of the radial cylinder 73a is connected to the radial electromagnet 71a, and the radial cylinder 73a is used to drive the radial electromagnet 71a to move so as to adjust a magnetic gap between the radial electromagnet 71a and the radial armature 72a, so that a magnetic force between the radial electromagnet 71a and the radial armature 72a can be adjusted, and thus, a load applied to the bearing test piece 2 can be adjusted.

Of course, the magnetic force between the radial electromagnet 71a and the radial armature 72a can also be adjusted by adjusting the magnitude of the current when the radial electromagnet 71a is energized, thereby adjusting the magnitude of the load applied to the bearing piece 2.

In the present embodiment, the radial cylinder 73a is mounted on the support module 10 through the radial cylinder support 731 a.

Referring to fig. 3, 4 and 9, in one embodiment, the radial electromagnet 71a includes a radial inner magnet 711a, a radial coil 712a and a radial isolation housing 713a. The radial coil 712a is wound outside the radial inner magnet 711 a. The radially inner magnet 711a and the radial coil 712a are each located within the radial isolation housing 713a. One end of radially inner magnet 711a is disposed opposite to radial armature 72a such that a magnetic force is generated between radially inner magnet 711a and radial armature 72a when radial coil 712a is energized. Radial isolation housing 713a is sealingly connected to radially inner magnet 711a near an end of radial armature 72 a. One end of radial isolation housing 713a facing away from radial armature 72a is sealingly connected to vacuum vessel 21, and the inside of radial isolation housing 713a communicates with the outside of vacuum vessel 21.

Since the radially inner magnet 711a and the radially coil 712a are both located in the radially isolating housing 713a, the inside of the radially isolating housing 713a communicates with the outside of the vacuum vessel 21, so that heat generated by the radially coil 712a when the radial electromagnet 71a operates can be dissipated to the atmosphere outside the vacuum vessel 21. Since radial isolation housing 713a is sealingly connected to radially inner magnet 711a at an end thereof adjacent to radial armature 72a, an end of radial isolation housing 713a facing away from radial armature 72a is sealingly connected to vacuum vessel 21, thereby enabling a vacuum environment to be maintained within vacuum vessel 21.

In one embodiment, the radial loading module 70a further includes a radial adjustment bellows 75a. Radial adjustment bellows 75a is disposed on a side of radial isolation housing 713a facing away from radial armature 72 a. One end of the radial regulating bellows 75a is connected with the radial isolating housing 713a in a sealing manner, the other end of the radial regulating bellows 75a is connected with the vacuum vessel 21 in a sealing manner, and the inside of the radial regulating bellows 75a is communicated with the outside of the vacuum vessel 21.

Since the inside of the radial regulating bellows 75a communicates with the outside of the vacuum vessel 21, heat generated by the radial coil 712a when the radial electromagnet 71a operates can be emitted to the atmosphere outside the vacuum vessel 21 via the radial isolation housing 713a and the radial regulating bellows 75a. Since one end of the radial regulating bellows 75a is sealingly connected to the radial isolation housing 713a, the other end of the radial regulating bellows 75a is sealingly connected to the vacuum vessel 21, so that the vacuum environment can be maintained in the vacuum vessel 21.

Further, by providing the radial adjustment bellows 75a between the vacuum chamber 21 and the radial electromagnet 71a, the telescopic characteristic of the radial adjustment bellows 75a allows the radial electromagnet 71a to move relative to the vacuum chamber 21, and thus the magnetic gap between the radial electromagnet 71a and the radial armature 72a can be adjusted.

Referring to fig. 3, 4 and 9, in one embodiment, the radial loading module 70a further includes a radial loading force sensor 74a. The radial load force sensor 74a is connected between the radial cylinder 73a and the radial electromagnet 71a, so that the radial load force sensor 74a can detect the magnitude of the magnetic force between the radial electromagnet 71a and the radial armature 72a, and thus can obtain the magnitude of the load force on the bearing test piece 2.

Referring to fig. 3, 4 and 9, in one embodiment, the radial loading module 70a further includes a radial connection rod 76a. One end of the radial connecting rod 76a is connected to the radial electromagnet 71a, and the other end extends outside the vacuum vessel 21 and is connected to the output end of the radial cylinder 73a, thereby facilitating connection of the radial electromagnet 71a to the output end of the radial cylinder 73 a. In the present embodiment, a radial load force sensor 74a is connected between the radial cylinder 73a and the radial connecting rod 76a.

Referring to fig. 3, 4 and 9, in one embodiment, the radial loading module 70a further includes a radial guiding structure 77a. The radial guide structure 77a is used to guide the moving direction of the radial electromagnet 71a, thereby ensuring the accurate loading direction. In this embodiment, the radial guide structure 77a is a cross roller guide rail provided at the bottom inside the vacuum vessel 21.

Referring to fig. 3, 4 and 10, in one embodiment, the axial loading module 70b includes: an axial electromagnet 71b and an axial armature 72b. The axial electromagnet 71b is provided in the vacuum vessel 21. Axial armature 72b is located on an axial side of clamp module 30 and is connected to clamp module 30. When the axial electromagnet 71b is energized, a magnetic force is generated that attracts the axial armature 72b, so that the clamp module 30 can be loaded in the axial direction by the magnetic force between the axial electromagnet 71b and the axial armature 72b, so that the bearing test piece 2 can be loaded in the axial direction. The axial electromagnet 71b loses its magnetic force when it is deenergized, so that the bearing test piece 2 can be unloaded.

Specifically in this embodiment, axial armature 72b is coupled to clamp module 30 via axial load socket 721.

In one embodiment, the surface of axial electromagnet 71b facing axial armature 72b and the surface of axial armature 72b facing axial electromagnet 71b are both part-spherical, so that when axial electromagnet 71b and axial armature 72b are assembled, the two opposite part-spherical surfaces can be self-calibrated to compensate for deflection problems caused by machining, assembly and the like.

Referring to fig. 3, 4 and 10, in an embodiment, the axial loading module 70b further includes an axial electric cylinder 73b, an output end of the axial electric cylinder 73b is connected to the axial electromagnet 71b, and the axial electric cylinder 73b is used for driving the axial electromagnet 71b to move so as to adjust a magnetic gap between the axial electromagnet 71b and the axial armature 72b, so that a magnetic force between the axial electromagnet 71b and the axial armature 72b can be adjusted, and thus, a load applied to the bearing test piece 2 can be adjusted.

Of course, the magnetic force between the axial electromagnet 71b and the axial armature 72b can also be adjusted by adjusting the magnitude of the current when the axial electromagnet 71b is energized, thereby adjusting the magnitude of the load applied to the bearing piece 2.

In one embodiment, the axial cylinder 73b is mounted to the vacuum vessel 21 by an axial cylinder support 731 b.

Specifically, in the present embodiment, the axial cylinder supporting portion 731b includes a support column 7311 and a pressure receiving plate 7312, and one end of the support column 7311 is fixed to the vacuum vessel 21 and the other end is fixed to the pressure receiving plate 7312. The bearing cylinder 73b is mounted on the bearing plate 7312 through a bearing cylinder mount 732.

Referring to fig. 3, 4 and 10, in one embodiment, the axial electromagnet 71b includes an axial inner magnet 711b, an axial coil 712b and an axial isolation housing 713b. The axial coil 712b is wound outside the axial inner magnet 711 b. The axial inner magnet 711b and the axial coil 712b are both located within the axial isolation housing 713b. One end of the axially inner magnet 711b is disposed opposite the axial armature 72b such that a magnetic force is generated between the axially inner magnet 711b and the axial armature 72b when the axial coil 712b is energized. An end of axial isolation housing 713b adjacent axial armature 72b is sealingly connected to axial inner magnet 711 b. An end of axial isolation housing 713b facing away from axial armature 72b is sealingly connected to vacuum vessel 21, and an inside of axial isolation housing 713b communicates with an outside of vacuum vessel 21.

Since the axial inner magnet 711b and the axial coil 712b are both located in the axial isolation housing 713b, the inside of the axial isolation housing 713b communicates with the outside of the vacuum vessel 21, so that heat generated by the axial coil 712b when the axial electromagnet 71b operates can be dissipated to the atmosphere outside the vacuum vessel 21. Since the end of axial isolation housing 713b adjacent axial armature 72b is sealingly connected to axial inner magnet 711b, the end of axial isolation housing 713b facing away from axial armature 72b is sealingly connected to vacuum vessel 21, thereby enabling a vacuum environment to be maintained within vacuum vessel 21.

In particular, in this embodiment, axial isolation housing 713b is an external magnet that may also be used to create a magnetic force with axial armature 72 b.

In one embodiment, the axial loading module 70b further includes an axial adjustment bellows 75b. An axial adjustment bellows 75b is provided on a side of axial isolation housing 713b facing away from axial armature 72 b. One end of the axial adjustment bellows 75b is connected with the axial isolation housing 713b in a sealing manner, the other end of the axial adjustment bellows 75b is connected with the vacuum vessel 21 in a sealing manner, and the inside of the axial adjustment bellows 75b is communicated with the outside of the vacuum vessel 21.

Since the inside of the axial regulating bellows 75b communicates with the outside of the vacuum vessel 21, the heat generated by the axial coil 712b when the axial electromagnet 71b is operated can be emitted to the atmosphere outside the vacuum vessel 21 via the axial isolation housing 713b and the axial regulating bellows 75b. Since one end of the axial adjustment bellows 75b is sealingly connected to the axial isolation housing 713b, the other end of the axial adjustment bellows 75b is sealingly connected to the vacuum vessel 21, so that a vacuum environment can be maintained in the vacuum vessel 21.

Further, by providing the axial adjustment bellows 75b between the vacuum chamber 21 and the axial electromagnet 71b, the telescopic characteristic of the axial adjustment bellows 75b allows the axial electromagnet 71b to move relative to the vacuum chamber 21, and thus the magnetic gap between the axial electromagnet 71b and the axial armature 72b can be adjusted.

Referring to fig. 3, 4 and 10, in an embodiment, the axial loading module 70b further includes a compensating bellows 733. One end of the compensation bellows 733 is connected to the pressure receiving plate 7312 in a sealed manner and is in communication with the axial direction adjustment bellows 75b, and the other end of the compensation bellows 733 is connected to the outside of the vacuum chamber 21 in a sealed manner and is connected to the vacuum chamber 21 in a sealed manner. The compensation bellows 733 compensates for machining and assembly errors of the support columns 7311 and the bearing plates 7312.

Since one end of the compensation bellows 733 is in communication with the axial adjustment bellows 75b, the inside of the compensation bellows 733 communicates with the outside of the vacuum vessel 21, and thus, heat generated by the axial coil 712b when the axial electromagnet 71b operates can be emitted to the atmosphere outside the vacuum vessel 21 via the axial isolation housing 713b and the axial adjustment bellows 75b, and the compensation bellows 733.

Since one end of the compensation bellows 733 is connected to the pressure receiving plate 7312 in a sealed manner, the other end of the compensation bellows 733 is connected to the vacuum chamber 21 in a sealed manner, and a vacuum environment can be maintained in the vacuum chamber 21.

Referring to fig. 3, 4 and 10, in one embodiment, the axial loading module 70b further includes an axial loading force sensor 74b. The axial force sensor 74b is connected between the axial cylinder 73b and the axial electromagnet 71b, so that the axial force sensor 74b can detect the magnitude of the magnetic force between the axial electromagnet 71b and the axial armature 72b, and can obtain the magnitude of the loading force on the bearing test piece 2.

Referring to fig. 3, 4 and 10, in one embodiment, the axial loading module 70b further includes an axial connecting rod 76b. One end of the axial connecting rod 76b is connected to the axial electromagnet 71b, and the other end extends outside the vacuum vessel 21 and is connected to the output end of the axial cylinder 73b, thereby facilitating the connection of the axial electromagnet 71b to the output end of the axial cylinder 73 b. In the present embodiment, an axial loading force sensor 74b is connected between the axial cylinder 73b and the axial connecting rod 76b.

Referring to fig. 3, 4 and 10, in one embodiment, the axial loading module 70b further includes an axial guiding structure 77b. The axial guide structure 77b is used to guide the moving direction of the axial electromagnet 71b, thereby ensuring the loading direction to be accurate. In the present embodiment, the axial guide structure 77b includes a guide post 771 and a guide linear bearing 772. The guide posts 771 are movably threaded into the guide linear bearings 772. The guide post 771 is fixed to the pressure receiving plate 7312, and the guide linear bearing 772 is fixed to the axial electromagnet 71 b.

Referring to fig. 11 in combination with fig. 12, in one embodiment, the measurement module 80 includes a force transfer beam 81, a force sensor 82, and a sensor support 821. One end of the transfer beam 81 is connected to the jig module 30, and the other end extends radially outward of the jig module 30. The sensor support 821 is provided in the vacuum vessel 21, and the force sensor 82 is provided on the sensor support 821 so as to face the transfer beam 81.

Friction moment M generated between the inner ring 2b of the bearing test piece 2 and the outer ring 2a when the inner ring 2b rotates _f The force transmission beam 81 rotates towards the direction of pressing the force sensor 82, so that the pressing force F is generated between the force transmission beam 81 and the force sensor 82 _l And the force sensor 82 can measure the pressing force F _l And transmits the value of (2) to the measurement control system. The measurement control system is then able to control the pressure force F _l And the pressing force F _l The force arm L of the force arm (L) is calculated to obtain the friction moment M _f 。

Referring to fig. 3 and 4, in an embodiment, the sensor support 821 and the upper bearing housing support 4321 share the same structure.

Referring to fig. 11 to 13, in an embodiment, the measurement module 80 further includes a pressure rod 83 and a force application ball 85. One end of the pressure rod 83 is fixedly connected with the force sensor 82, and the other end faces the force transfer beam 81 and is fixedly connected with the force application ball 85.

Friction moment M generated between the inner ring 2b of the bearing test piece 2 and the outer ring 2a when the inner ring 2b rotates _f The force transfer beam 81 rotates in the direction of pressing the force application ball 85, so that a pressing force F is generated between the force transfer beam 81 and the force application ball 85 _l And the force sensor 82 can measure the pressing force F _l And transmits the value of (2) to the measurement control system. The measurement control system is then able to control the pressure force F _l And the pressing force F _l The force arm L of the force arm (L) is calculated to obtain the friction moment M _f . The force transfer beam 81 transfers force to the force sensor 82 through the force application ball 85, and the force transfer beam 81 and the force application ball 85 are in point contact, so that the force sensor 82 can be more accurately and effectively applied.

Referring to fig. 11, in one embodiment, the force sensor 82 is fixed to the sensor support 821 via the sensor adapter 822. One end of the pressure rod 83 is fixed to the sensor support 821 via the pressure rod fitting table 831, thereby being indirectly fixedly connected to the force sensor 82.

Referring to FIG. 11, in one embodiment, a force ball 85 is secured to the pressure bar 83 by a ball bearing assembly 84. Referring to fig. 13, the ball rest assembly 84 includes a ball rest base 841 and a ball rest screw 842. The ball holder chassis 841 has a receiving chamber therein for receiving the urging ball 85. The force applying ball 85 is disposed in the receiving chamber and partially protrudes from one end of the ball support chassis 841. The other end of the ball mount chassis 841 is screwed with the ball mount screw 842, so that the ball mount screw 842 can rotate relative to the ball mount chassis 841 so as to abut against the urging ball 85, thereby fixing the urging ball 85. Ball support screw 842 is threadably coupled to pressure bar 83.

Referring to fig. 11, in one embodiment, the measurement module 80 is located at an end of the fixture module 30 facing away from the radial loading module 70 a. The force transfer beam 81 is provided with a weight 86, and the weight 86 is used to balance the weight of the radial armature 72a, thereby preventing the accuracy of the test from being affected by the inclination of the clamp module 30.

In one embodiment, the force sensor 82 may be connected to an external measurement control system through a vacuum cable connection (not shown) provided on the vacuum vessel 21.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. An ultralow temperature vacuum bearing testing machine, which is characterized by comprising:

a support module;

The measuring module is arranged in the vacuum container and is used for measuring the friction torque of the bearing test piece;

wherein, the inner race refrigeration module includes: the device comprises a cold guide chamber, a hollow shaft and a liquid nitrogen pipe; the cold guide chamber is arranged in the vacuum container and is connected with one end of the main shaft; the hollow shaft is connected with one end of the cold guide chamber, which is far away from the main shaft, and is communicated with the cold guide chamber, one end of the hollow shaft, which is far away from the cold guide chamber, extends out of the vacuum container and is driven to rotate by the driving mechanism, one end of the hollow shaft, which extends out of the vacuum container, is sleeved with a pressure barrel, the pressure barrel is communicated with the hollow shaft, and the pressure barrel is used for being connected with an air pump; the liquid nitrogen pipe penetrates through the hollow shaft, one end of the liquid nitrogen pipe extends out of the hollow shaft and extends into the cold guide chamber, and the other end of the liquid nitrogen pipe extends out of the hollow shaft and is used for being connected with a liquid nitrogen source; the liquid nitrogen pipe is characterized in that a convex column is arranged at the bottom of the inner cavity of the cold conducting chamber, a through hole is formed in the convex column, two ends of the through hole are respectively communicated with the inner cavity of the cold conducting chamber and the hollow shaft, and one end of the liquid nitrogen pipe extends out of the through hole and extends out of the convex column in the radial direction.

2. The ultra-low temperature vacuum bearing testing machine according to claim 1, wherein,

the inner ring refrigerating module further comprises a temperature sensor and a conductive slip ring, the conductive slip ring is arranged at one end of the hollow shaft extending out of the vacuum container, the temperature sensor is arranged in the cold conduction chamber, the temperature sensor is connected with the inner ring of the conductive slip ring through a temperature measurement wire penetrating through the hollow shaft, and the outer ring of the conductive slip ring is used for being connected to a measurement control system;

3. The ultra-low temperature vacuum bearing testing machine according to claim 1, wherein the fixture module comprises a fixture body and a fixture housing, an annular groove is formed in the inner side wall of the fixture body, the annular groove is used for being matched with the outer ring of the bearing test piece, and the fixture housing is sleeved and fixed outside the fixture body.

4. The ultra-low temperature vacuum bearing tester according to claim 3, wherein,

The clamp shell is provided with a liquid nitrogen channel;

the outer ring refrigeration module includes:

5. The ultralow temperature vacuum bearing testing machine according to claim 1, wherein the spindle module comprises a support bearing and a bearing seat, the two ends of the spindle are respectively connected with the support bearing, and each support bearing is connected with the vacuum container through the corresponding bearing seat; the supporting bearing connected with one end of the main shaft, which is close to the inner ring refrigerating module, adopts a back-mounted angular contact bearing; the main shaft deviates from the support bearing connected with one end of the inner ring refrigerating module and adopts a cylindrical roller bearing.

6. The ultra-low temperature vacuum bearing testing machine according to claim 1, wherein,

the number of the loading modules is two, one is a radial loading module for loading the bearing test piece in the radial direction, and the other is an axial loading module for loading the bearing test piece in the axial direction;

7. The machine of claim 6, wherein the electromagnet is disposed opposite the armature, and wherein the surface of the electromagnet facing the armature and the surface of the armature facing the electromagnet are both part spherical surfaces.

8. The ultra-low temperature vacuum bearing tester according to claim 6, wherein,

the electromagnet comprises an inner magnet, a coil and an isolation shell, wherein the coil is wound on the outer side of the inner magnet, the inner magnet and the coil are both positioned in the isolation shell, one end of the inner magnet is opposite to the armature, and one end, close to the armature, of the isolation shell is in sealing connection with the inner magnet;

9. The ultra-low temperature vacuum bearing testing machine according to claim 1, wherein,

the measurement module includes:

a sensor support portion provided to the vacuum vessel;

a force sensor provided to the sensor support portion;

one end of the pressure rod is fixedly connected with the force sensor; and

10. The machine of claim 1, wherein the end of the hollow shaft extending out of the vacuum vessel is rotatably connected to the support module via a bearing.