Multi-station high-low temperature service life testing equipment for ball screw pair for automobile braking

Abstract

The invention discloses multi-station high-low temperature life testing equipment for a ball screw pair for automobile braking. The multi-station high-low temperature life testing equipment comprises a driving mechanism, a high-low temperature environment box, a loading mechanism, an experiment frame, a cast iron lathe bed and the like. The driving mechanism is used for driving the detected nut sample piece to rotate and monitoring the input torque in real time; the high and low temperature environment box is used for providing environment temperatures under different working conditions for the tested sample piece; and the loading mechanism is used for stably loading the ball screw and monitoring the loading force in real time. The experiment frame is used for bearing variable load generated by the loading mechanism and ensuring stable work of the test equipment. The casting lathe bed is used for providing a base plane with certain horizontal precision and installing the experiment frame and the linear guide rail. The device is compact in layout and reliable in structure, can provide service life tests and comprehensive efficiency tests for a plurality of ball screw pairs for automobile braking in high and low temperature environments at the same time, greatly shortens the verification period of the service life conditions of the automobile ball screws in the high and low temperature environments, and is high in measurement efficiency and space utilization rate.

Description

Technical Field

[0001] The invention belongs to the field of ball screw testing, and in particular relates to a high and low temperature life testing device for a ball screw pair for automobile braking. Background Art

[0002] Compared with traditional trapezoidal screws, ball screws are widely used in machine tools, automobiles, aerospace and other fields due to their high precision, high efficiency and high reliability. In the automotive field, ball screw pairs can be used in the steering system, braking system, accelerator pedal, seat adjustment system and glass window lifting system of automobiles to improve the accuracy, efficiency and safety of automobiles. In recent years, with the popularization of new energy vehicles, ball screw pairs have been used more and more widely in automobile braking systems. In electronic hydraulic automobile braking systems, vacuum boosters are gradually replaced by electric boosters with ball screw pairs as the main transmission components; in electronic mechanical braking systems, the motor provides braking force through the reducer and ball screw pairs. In the future, the market size of ball screw pairs for automotive braking will increase significantly, becoming the focus of domestic and foreign automotive parts manufacturers and ball screw manufacturers.

[0003] As the core safety component in the braking system, the life reliability of the ball screw pair for automobile brakes directly determines the safety of the entire vehicle during driving. Compared with the high precision, high rigidity and thermal stability of machine tool ball screws, the automotive field pays more attention to the service life of ball screws, especially the service life in high and low temperature environments. Its design life needs to meet 7 different working conditions, and the test environment temperature range is required to be between -40 and 150°C. Existing life test equipment is difficult to meet the life test of small ball screws under high and low temperature conditions, and is often limited by the device structure. It can only perform life tests on a single ball screw. Since the design life of the ball screw for automobile brakes is relatively long, it generally takes several months to complete the life test of a ball screw, which seriously affects the development cycle of the ball screw for automobile brakes. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-station high and low temperature life test device for a ball screw pair for automobile braking, so as to significantly shorten the verification cycle of the high and low temperature environment life of the automobile ball screw and improve the test efficiency.

[0005] The technical solution to achieve the purpose of the present invention is:

[0006] A ball screw pair multi-station high and low temperature life test equipment, comprising:

[0007] Bed, used to install the experimental frame and linear sliding pair;

[0008] The high and low temperature environment box is used to accommodate the ball screw sample to provide the working temperature of the test condition. It is connected to the bed through a linear sliding pair and can slide relative to the bed to enter and exit the experimental frame, which is convenient for the installation and removal of the ball screw sample to be tested;

[0009] The experimental frame is equipped with multiple stations for installing the driving mechanism and the loading mechanism;

[0010] A driving mechanism, connected to the nut of the ball screw sample to be tested, and used for converting its own rotation into the linear motion of the screw of the ball screw pair sample to be tested;

[0011] The loading mechanism is connected to the screw of the ball screw sample under test, and is used to simulate the demand for sudden change of loading force in the load spectrum of an automobile to passively load the ball screw sample under test.

[0012] Compared with the prior art, the present invention has the following significant advantages:

[0013] 1) The testing equipment of the present invention utilizes a high and low temperature environment box with a convex box body and upper and lower openings, and combines a sealing flange with a sealing rubber ring to enable the equipment to perform life tests on ball screw pairs in high and low temperature environments, with good sealing, heat insulation, and constant temperature and humidity effects; 2) The testing equipment of the present invention utilizes the reaction force generated by the spring when the spring is compressed to perform axial loading on the automotive ball screw pair. Compared with the existing magnetic powder brake, eddy current brake, and hydraulic cylinder brake, it can provide a unidirectional loading force that increases linearly with the compression distance. The loading force is stable, easy to replace, and has a low cost. And it is possible to realize a sudden change in spring stiffness by connecting springs in parallel, so as to better fit the load spectrum of the automotive ball screw; 3) The test equipment of the present invention has a compact and reasonable structural layout, large load-bearing capacity and stable support, and can simultaneously carry out life tests of three ball screw pairs under high and low temperature environments, and is easy to install and disassemble; 4) The test equipment of the present invention is a vertical layout, which can make full use of the vertical space compared to the existing horizontal layout, and save the occupied area of ​​the test equipment to a greater extent; 5) The test equipment of the present invention can also complete the vibration and temperature rise test of the ball screw pair for automotive braking through the external acceleration sensor and temperature sensor through the wire threading hole of the box body; 6) The test equipment of the present invention can calculate the comprehensive dynamic efficiency and static efficiency of the ball screw sample under high and low temperature by analyzing the input torque and loading force collected in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the overall structure of a multi-station high and low temperature life test equipment for a ball screw pair for automobile braking according to the present invention;

[0015] Figure 2It is a schematic diagram of the exploded structure of a transmission mechanism of a multi-station high and low temperature life test equipment for a ball screw pair for automobile braking according to the present invention;

[0016] Figure 3 It is a schematic diagram of the exploded structure of a loading mechanism of a multi-station high and low temperature life test equipment for a ball screw pair for automobile braking according to the present invention;

[0017] Figure 4 It is a schematic diagram of the explosion structure of a sealing device of a high and low temperature environment box of a multi-station high and low temperature life test equipment for a ball screw pair for automobile braking according to the present invention;

[0018] Figure 5 It is a schematic diagram of the explosion structure of a ball screw sample to be tested in a multi-station high and low temperature life test device for a ball screw pair for automobile braking of the present invention;

[0019] The numbers in the figure mean:

[0020] 1. Driving mechanism, 2. Experimental frame, 3. High and low temperature environment chamber, 4. Loading mechanism, 5. Casting bed, 6. Leveling shim; 7. Small pulley, 8. First transmission shaft, 9. Shaft retaining ring, 10. First bearing end cover, 11. Deep groove ball bearing, 12. First bearing seat, 13. First coupling, 14. Dynamic torque sensor, 15. Sensor fixing seat, 16. Second coupling, 17. Locking nut, 18. First bearing spacer, 19. First spherical roller bearing, 20. Second bearing spacer, 21. Second spherical roller bearing, 22. Second transmission shaft, 23. Tested ball screw sample, 24. Large pulley, 25. Synchronous belt, 26. Motor fixing seat, 27. Servo motor, 28. Second bearing end cover, 29. Second shaft Bearing seat, 30, nut bearing seat, 31 third bearing end cover; 32, pressure head connecting block, 33, pressure rod, 34, first graphite copper sleeve, 35, pressure rod fixing seat, 36, second graphite copper sleeve, 37, tension pressure sensor, 38, spring pressure cover, 39, spring guide rod, 40, first loading spring, 41, second loading spring, 42, spring seat, 43, hollow pad, 44, pad, 45, spring bottom plate, 46, adjusting nut; 47, sealing rubber ring, 48, first sealing flange, 49, epoxy resin tube, 50, second sealing flange, 51, insulation box, 52, control box, 53, slider, 54, wedge block, 55, linear guide; 56, planetary pin, 57, four-point contact bearing, 58, nut, 59, screw. DETAILED DESCRIPTION

[0021] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0022] Combination Figure 1 to Figure 5, a ball screw pair multi-station high and low temperature life test equipment of this embodiment includes a driving mechanism 1, a test frame 2, a high and low temperature environment box 3, a loading mechanism 4, a casting bed 5, a leveling pad 6, a linear guide rail 55, and a slider 53;

[0023] The driving mechanism 1 includes a servo motor 27, a motor fixing seat 26, a large pulley 24, a small pulley 7, a synchronous belt 25, a first transmission shaft 8, a first bearing seat 12, a first bearing end cover 10, a shaft retaining ring 9, a deep groove ball bearing 11, a first coupling 13, a dynamic torque sensor 14, a sensor fixing seat 15, a second coupling 16, a second transmission shaft 22, a locking nut 17, a first bearing spacer 18, a first spherical roller bearing 19, a second bearing spacer 20, a second bearing end cover 28, a second bearing seat 29, a second spherical roller bearing 21, a nut bearing seat 30, and a third bearing end cover 31; the servo motor 27 is installed on the motor fixing seat 26 The motor fixing seat 26 is fixed to the top of the experimental frame 2 by screws; the large pulley 24 is connected to the output shaft of the servo motor 27 by a flat key, and the small pulley 7 is connected to the input end of the first transmission shaft 8 by a flat key. The large pulley 24 and the small pulley 7 are connected by a synchronous belt 25 to form a synchronous transmission mechanism; the first transmission shaft 8 is installed in the first bearing seat 12 through a deep groove ball bearing 11, and the first bearing seat 12 is installed on the side plate of the motor fixing seat 26; the first bearing end cover 10 fixes the outer ring of the deep groove ball bearing 11 in the first bearing seat 12, and fixes the inner ring of the deep groove ball bearing 11 to the shoulder of the first transmission shaft 8 through the shaft retaining ring 9, and the output end of the first transmission shaft 8 The first coupling 13 is connected to the input end of the dynamic torque sensor 14; the dynamic torque sensor 14 is connected to the sensor fixing seat 15, and the sensor fixing seat 15 is installed on one side of the motor fixing seat 26. The output end of the dynamic torque sensor 14 is connected to the input end of the second transmission shaft 22 through the second coupling 16. Both ends of the second transmission shaft 22 are installed in the second bearing seat 29 through the first spherical roller bearing 19 and the second spherical roller bearing 21; the second bearing end cover 28 fixes the outer ring of the first spherical roller bearing 19 in the second bearing seat 29, and fixes the inner ring of the first spherical bearing 19 to the second transmission shaft through the locking nut 17 and the first bearing spacer 18. 20; the nut bearing seat 30 is installed on the end face of the second bearing seat 29 by screws, one end of the nut bearing seat 30 is raised, which is used to fix the outer ring of the second spherical roller bearing 21 in the second bearing seat 29, and is arranged in the second bearing seat 29 through the second bearing spacer 20, which is used to fix the inner ring of the second spherical roller bearing 21 at the shoulder of the second transmission shaft 22; the ball screw sample 23 to be tested includes a planetary pin 56, a four-point contact bearing 57, a nut 58, and a screw 59, and the nut 58 serves as the inner ring of the four-point contact bearing 57, and a raceway is machined on its outer circle; the third bearing end cover 31 fixes the outer ring of the four-point contact bearing 57 in the nut bearing seat 30;The second bearing seat 29 is connected to the inner side of the top plate of the experimental frame 2. A pin hole is processed at the output end of the second transmission shaft 22. The nut 58 set at one end of the ball screw sample 23 to be tested is connected to the pin hole of the second transmission shaft 22 through three planetary pins 56. The second transmission shaft 22 drives the nut 58 through the planetary pins 56 to complete the rotational motion under the support of the internal four-point contact bearing 57, and finally converts it into the linear motion of the screw 59.

[0024] Furthermore, the loading mechanism 4 includes a pressure head connecting block 32, a pressure rod 33, a first graphite copper sleeve 34, a second graphite copper sleeve 36, a pressure rod fixing seat 35, a tension pressure sensor 37, a spring pressure cover 38, a first loading spring 40, a second loading spring 41, a spring guide rod 39, a hollow pad 43, a spring seat 42, a spring bottom plate 45, an adjusting nut 46, and a pad 44.The groove at the upper end of the pressure head connecting block 32 is positioned and matched with the convex surface of the other end face of the screw 59 of the ball screw sample 23 to be tested, and is fastened by screws in the threaded holes on the side of the pressure head connecting block 32. The pressure head connecting block 32 is installed at one end of the pressure rod 33, and the pressure rod 33 is installed in the pressure rod fixing seat 35 through the first graphite copper sleeve 34 and the second graphite copper sleeve 36. The pressure rod fixing seat 35 is connected to the bottom of the experimental frame 2, and the other end of the pressure rod 33 is connected to the threaded end of the tension pressure sensor 37, and the other end of the tension pressure sensor 37 is fixed to the spring cover 38 by screws; three loading springs are installed in the spring seat 42, including a first loading spring 40 located in the center and a symmetrically arranged The two second loading springs 41 on both sides of the first loading spring 40 have different stiffness and free length; the first loading spring 40 and the cushion block 44 are installed between the spring pressure cover 38 and the spring bottom plate 45, and the first loading spring 40 of different lengths can be selected by adjusting the length of the cushion block 44, thereby changing the stiffness of the first loading spring 40 to meet the loading requirements under the vehicle load spectrum requirements; the second loading spring 41 and the hollow cushion block 43 are installed between the spring pressure cover 38 and the spring bottom plate 45, and the second loading spring 42 of different lengths can be selected by adjusting the length of the hollow cushion block 43, thereby changing the stiffness of the second loading spring 42 to meet the loading requirements under the vehicle load spectrum requirements. The spring bottom plate 45 is connected to the bottom of the spring seat 42 by screws to limit the movement of one end of the loading spring; one side of the spring guide rod 39 is fixed to the experimental frame 2 by screws, and the other side is processed with threads, and is connected to the spring bottom plate 45 by a double adjusting nut 46. The position of the adjusting nut 46 can be adjusted to control the pre-compression amount of the spring. The spring guide rod 39 has a guiding function to ensure that the spring cover plate 38 moves linearly along the rod body of the spring guide rod 39, compressing the first heavy-load spring 40 and the second heavy-load spring 41 to generate a loading force; since the relationship between the loading force and the extension distance of the lead screw in the automobile load spectrum is not a linear relationship through the origin, a sudden bending line will be generated at a certain extension position of the lead screw line, so in order to meet the loading change, the sudden change of stiffness needs to be fitted by springs. By adjusting the length of the pad 44 and the hollow pad 43, the distance of compression of the two springs can be controlled, so that the ball screw sample 23 under test drives the pressure rod 33 and the spring pressure cover 38 to compress the first loading spring 40 first. When the spring cover 38 contacts the second loading spring 41 after compressing one end distance, the three loading springs are connected in parallel at this time, and the total stiffness suddenly increases. The spring cover 38 compresses the three loading springs to the specified position at the same time, realizing the sudden change of loading force in the automobile load spectrum. In addition, by controlling the dimensional tolerance of the pad 44 and the hollow pad 43, the loading force error caused by the spring length processing error can be minimized.

[0025] Furthermore, the high and low temperature environment box includes a control box body 52, an insulation box body 51, a first sealing flange 48, an epoxy resin tube 49, a second sealing flange 50, and a sealing rubber ring 47. The bottom of the high and low temperature environment box 3 is installed on a linear guide rail 55 through a slider 53. The high and low temperature environment box 3 can freely move linearly in and out of the experimental frame 2 on the linear guide rail 55, which is convenient for the installation and disassembly of the ball screw sample 23 to be tested; the high and low temperature environment box 3 has a special structural form, and the insulation box body 51 is convex and vertically connected to the control box body 52; three test holes are processed on the upper and lower sides of the insulation box body 51, which are used for the external driving mechanism 1 and the loading mechanism 4 to connect the ball screw sample 23 to be tested in the insulation box body 51, so as to realize the driving, loading and temperature change of the tested sample; there are gaps between the upper and lower test holes and the second bearing seat 29 and the pressure rod fixing seat 35 respectively. The existence of the gap will cause external air to enter, and condensation will occur under long-term operation at low temperature. The constant temperature and humidity effect is not good and may even fail to reach the set temperature. The present invention adopts the method of matching the sealing flange with the sealing rubber ring 47 to realize elastic sealing. The first sealing flange 48 and the second sealing flange 50 are used in pairs and are respectively installed on the upper and lower sides of the test holes at the top and bottom of the insulation box 51 by screws. A groove is processed on the outer circle of the second bearing seat 29 for installing the sealing rubber ring 47. The second bearing seat 29 and the pressure rod fixing seat 35 are respectively connected with the first sealing flange 48 and the second sealing flange 50 to complete the gas sealing by squeezing the sealing rubber ring 47. An epoxy resin tube 49 is installed between the first sealing flange 48 and the second sealing flange 50. The second bearing seat 29 and the epoxy resin tube 49 are filled with heat insulation cotton to reduce the heat loss inside the box and improve the constant temperature and humidity effect. This elastic matching method reduces the additional assembly stress caused by insufficient installation accuracy, hole processing accuracy, and horizontal positioning accuracy. The control box 52 can move relative to the bed, and the insulation box 51 is fixed on the upper end of the control box 52. The control box 52 is used to control the temperature of the insulation box 51.

[0026] Furthermore, the cast iron bed 5 is processed with four T-slots, two guide rail mounting slots and two wedge block mounting slots. The bottom of the experimental frame 2 is fixed in the T-slot of the cast iron bed 5 by T-nuts and bolts, the linear guide 55 is fixed in the guide rail mounting slot of the cast iron bed 5 by screws, and the wedge block 54 is screwed to press the linear guide 55 to radially position the linear guide 55 to ensure the installation accuracy of the linear guide 55; the leveling shim 6 is connected to the cast iron bed 5 by bolts and is used to adjust the level of the bed.

[0027] Furthermore, the experimental frame 2 will bend and deform under the spring loading force, causing the second bearing seat 29 installed on the experimental frame 2 to produce corresponding displacement, which will eventually cause the central axis between the second transmission shaft 22 and the second bearing seat 29 to deviate; the present invention selects the first spherical roller bearing 19 and the second spherical roller bearing 21 to support the second transmission shaft 22. The spherical roller bearing can withstand large axial and radial loads and has an automatic aligning function, which can compensate for the errors caused by non-concentricity and deflection, allowing the second transmission shaft 22 and the second bearing seat 29 to work normally under the condition of small relative inclination. Considering that the second transmission shaft 22 operates under high and low temperature conditions, the first spherical roller bearing 19 is set as a fixed end bearing, and the second spherical roller bearing 21 is used as a free end bearing. By adjusting the clearance of the free end of the second spherical roller bearing 21, the expansion and contraction of the shaft caused by temperature changes can be solved, and at the same time, the bearing can be prevented from being subjected to abnormal axial loads, which may cause it to become the cause of early damage.

[0028] When the multi-station high and low temperature life test equipment for a ball screw pair of the present invention is working, the high and low temperature environmental box is fixed in the experimental frame 2 according to the figure 1, and the driving mechanism 1, the loading mechanism 4 and the ball screw sample 23 to be tested are correctly installed in sequence; the first loading spring 40 and the second loading spring 41 with appropriate stiffness are selected according to the test requirements of the sample, and the position of the nut 46 is adjusted to control the appropriate initial compression force of the spring; the running-in stroke, the nut speed and the environmental box temperature are set in the software interface, and the servo motor switch is turned on. The output shaft of the servo motor 27 drives the first transmission shaft 8 to rotate after being decelerated by the synchronous pulley, and the dynamic torque sensor 14 collects the input torque of the first transmission shaft 8 in real time, and at the same time drives the second transmission shaft 22 to rotate through the second coupling 16. The second transmission shaft 22 is connected to the nut 58 of the sample to be tested through the planetary pin 56, and the driving nut 58 is internally The four-point contact bearing 57 completes the rotational motion, and finally converts it into the linear motion of the lead screw 59. During the extension process, the lead screw 59 pushes the pressure rod 33 to drive the tension pressure sensor 37 to compress the loading spring. The compressed loading spring generates elastic force to provide a linear load for the ball screw. The tension pressure sensor 37 collects the loading force in real time. The loading force can be adjusted by controlling the movement stroke of the lead screw and the stiffness of the spring. The input torque and loading force can be displayed in real time in the software interface of the industrial computer. By analyzing the input torque and loading force collected in real time, the comprehensive dynamic efficiency and static efficiency of the tested sample under high and low temperature conditions can be calculated. In addition, through the external acceleration sensor and temperature sensor of the box threading hole, the test equipment of the present invention can also complete the vibration and temperature rise test of the ball screw pair for automobile braking.

Claims

1. A multi-station high and low temperature life test equipment for ball screw pairs, characterized in that: include: Bed, used to install the experimental frame and linear sliding pair; The high and low temperature environment box is used to accommodate the ball screw sample to provide the working temperature of the test condition. It is connected to the bed through a linear sliding pair and can slide relative to the bed to enter and exit the experimental frame, which is convenient for the installation and removal of the ball screw sample to be tested; The experimental frame is equipped with multiple stations for installing the driving mechanism and the loading mechanism; A driving mechanism, connected to the nut of the ball screw sample to be tested, and used for converting its own rotation into the linear motion of the screw of the ball screw pair sample to be tested; The loading mechanism is connected to the screw of the ball screw sample under test, and is used to simulate the demand for sudden change of loading force in the load spectrum of an automobile to passively load the ball screw sample under test.

2. The ball screw pair multi-station high and low temperature life test equipment according to claim 1, characterized in that: The loading mechanism includes a pressure head connecting block, a pressure rod, a pressure rod fixing seat, a tension pressure sensor, a spring pressure cover, a first loading spring, a second loading spring, a spring guide rod, a hollow cushion block, a spring seat, a spring bottom plate, an adjusting nut and a cushion block; The pressure head connecting block is connected to the screw of the ball screw sample to be tested, the pressure head connecting block is connected to one end of the pressure rod, the pressure rod is rotatably supported in the pressure rod fixing seat, and the pressure rod fixing seat is connected to the experimental frame; the other end of the pressure rod is connected to one end of the tension pressure sensor, and the other end of the tension pressure sensor is fixed on the spring cover plate; three loading springs are installed in the spring seat, including a first loading spring located in the center and two second loading springs symmetrically arranged on both sides of the first loading spring; the first loading spring and the cushion block are installed between the spring pressure cover and the spring bottom plate, and the length of the cushion block can be adjusted to select whether to load or not. A first loading spring of the same length as the first loading spring can thereby change the stiffness of the first loading spring; the second loading spring and the hollow pad are installed between the spring pressure cover and the spring base plate, and second loading springs of different lengths can be selected by adjusting the length of the hollow pad to thereby change the stiffness of the second loading spring; the spring base plate is connected to the bottom of the spring seat to limit the movement of one end of the loading spring; one side of the spring guide rod is fixed to the experimental frame by a screw, and the other side is threaded and connected to the spring base plate by a double adjusting nut facing each other, and the pre-compression amount of the spring can be controlled by adjusting the position of the adjusting nut.

3. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 2, characterized in that: When the screw of the ball screw pair sample under test moves linearly, the ball screw sample under test drives the pressure rod and the spring pressure cover to compress the first loading spring first. When the spring cover plate contacts the second loading spring after compressing one end distance, the three loading springs are connected in parallel at this time, and the total stiffness increases suddenly. The spring cover plate compresses the three loading springs to the specified position at the same time, realizing the requirement of sudden change of loading force in the vehicle load spectrum.

4. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 2, characterized in that: The pressure rod is installed in the pressure rod fixing seat through a first graphite copper sleeve and a second graphite copper sleeve.

5. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 2, characterized in that: The groove at the upper end of the pressure head connecting block is positioned and matched with the raised surface of the screw end face of the ball screw sample to be tested, and is fastened by screws in the threaded holes on the side faces of the pressure head connecting block.

6. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 1, characterized in that: The driving mechanism includes a servo motor, a synchronous transmission mechanism, a first transmission shaft, a first coupling, a dynamic torque sensor, a second coupling, a second transmission shaft, a second bearing seat, a nut bearing seat and a third bearing end cover; the servo motor is installed on the top of the experimental frame and is connected to the input end of the first transmission shaft through the synchronous transmission mechanism; the output end of the first transmission shaft is connected to the input end of the dynamic torque sensor through the first coupling; the output end of the dynamic torque sensor is connected to the input end of the second transmission shaft through the second coupling, and the second transmission shaft is installed in the second bearing seat; the second bearing seat is connected to the top plate of the experimental frame; the nut bearing seat is installed on the end face of the second bearing seat, and the third bearing end cover fixes the outer ring of the four-point contact bearing of the ball screw sample to be tested in the nut bearing seat; the output end of the second transmission shaft is processed with a pin hole, and the nut set at one end of the ball screw sample to be tested is connected to the pin hole of the second transmission shaft through three planetary pins, and the second transmission shaft drives the nut through the planetary pin to complete the rotational motion under the support of the internal four-point contact bearing, and finally converts it into the linear motion of the screw.

7. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 6, characterized in that: Both ends of the second transmission shaft are installed in the second bearing seat through a first spherical roller bearing and a second spherical roller bearing; the first spherical roller bearing is set as a fixed end bearing, and the second spherical roller bearing is used as a free end bearing.

8. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 7, characterized in that: The outer ring of the first spherical roller bearing is fixed in the second bearing seat through the second bearing end cover, and the inner ring of the first spherical bearing is fixed to the second transmission shaft through the locking nut and the first bearing spacer; one end of the nut bearing seat is raised, which is used to fix the outer ring of the second spherical roller bearing in the second bearing seat, and is arranged in the second bearing seat through the second bearing spacer, which is used to fix the inner ring of the second spherical roller bearing at the shoulder of the second transmission shaft.

9. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 1, characterized in that: The high and low temperature environment box comprises a control box body, a heat preservation box body, a first sealing flange, an epoxy resin tube, a second sealing flange and a sealing rubber ring; The control box is connected to the bed through a linear sliding pair; the insulation box is connected to the control box and can move linearly in and out of the experimental frame; a plurality of test holes are provided on the upper and lower sides of the insulation box for external driving mechanism and loading mechanism to connect the ball screw sample to be tested in the insulation box; the first sealing flange and the second sealing flange are installed in pairs on the upper and lower sides of the test holes at the top and bottom of the insulation box respectively; the driving mechanism and the machine frame are both provided with sealing rubber rings, and gas sealing is completed by extruding the sealing rubber rings with the first sealing flange and the second sealing flange respectively; an epoxy resin tube is installed between the first sealing flange and the second sealing flange.

10. The multi-station high and low temperature life test equipment for ball screw pairs according to claim 1, characterized in that: The bed is provided with a leveling pad for adjusting the level of the bed.

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