Friction torque measuring instrument for precise pretightening force loading shafting

Abstract

A pretightening force accurate loading shafting friction torque measuring instrument belongs to the shafting detection technology field, the whole instrument is installed on a test bench, the upper side of the test bench is provided with a vibration isolation bench, the upper side of the vibration isolation bench is provided with a driving motor, the driving motor is connected with a support shafting through a flexible coupling, and the support shafting is provided with a vibration isolation device. The support shaft system is connected with a to-be-tested shaft system through a flange plate, the to-be-tested shaft system is provided with an eccentric plate, the eccentric plate is a force measuring point of a friction force sensor, the friction force sensor is installed on a height-angle-adjustable magnetic gauge stand, one end of the to-be-tested shaft system is provided with a pressing plate which is in contact with a bearing inner ring, and the center of the to-be-tested shaft system is provided with a pre-tightening bolt. The pre-tightening bolt sequentially penetrates through the insulating piezoelectric ceramics on the two sides, the pre-tightening force sensor and the pressing plate to be connected with a main shaft of the shafting to be tested, and the piezoelectric ceramics are controlled to be loaded through the conductive slip ring, the direct-current power source and the computer. The instrument realizes accurate loading of pretightening force controlled by a computer, and can measure shafting of different sizes.

Description

Technical Field

[0001] This invention relates to the field of shaft system testing technology, specifically to a preload-precision shaft friction torque measuring instrument. Background Technology

[0002] Shaft friction torque is a key technical indicator for evaluating the dynamic service performance of shaft systems. Its magnitude and stability directly determine the motion accuracy, transmission efficiency, and service life of precision equipment. Among the many structural parameters of shaft systems, the preload of the bearing inner ring is one of the core influencing factors: reasonable preload can effectively improve shaft stiffness, rotational accuracy, and operational smoothness; however, excessive preload will significantly increase friction torque, causing a rapid temperature rise, which in turn leads to material performance degradation and shortened service life. Therefore, determining the optimal preload is a crucial step in precision shaft system design. It must be accurately matched through high-precision measurement and testing, guided by theoretical models and based on specific operating conditions. However, most existing shaft friction torque measurement equipment relies heavily on operator experience when applying preload, lacking precise and quantifiable loading and control methods. This extensive preload method makes it impossible to systematically map friction torque under different preload conditions and establish a precise correlation model between preload and friction torque, thus constituting a significant bottleneck in shaft system performance optimization. With the increasing demands on shaft system performance in fields such as aerospace, optoelectronic detection, and precision manufacturing, higher requirements are being placed on friction torque measurement technology. This necessitates not only higher measurement accuracy but also dynamic process capture and adaptability to complex environments. Clearly, traditional measurement methods that rely on experience and lack sufficient preload control capabilities are no longer sufficient to meet the cutting-edge needs of advanced equipment for refined shaft system performance design and control. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the purpose of this invention is to design a preload-precision shaft friction torque measuring instrument to solve the problem of accurate preload application when measuring shaft friction torque mentioned in the background technology. It can also perform high-precision measurement of shaft friction torque under different preload conditions, avoid the error of manual preload application, and provide a precise and quantifiable loading and control method.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: a preload-loaded shaft friction torque measuring instrument, comprising a test bench, a vibration isolation table, a drive motor, a flexible coupling, a support shaft system, a flange, a shaft system to be tested, a pressure plate, a preload loading module, a vertical plate, and a magnetic gauge base. A vibration isolation table is fixedly installed on the upper side of the test bench. A drive motor is mounted on one side of the vibration isolation table. The shaft end of the drive motor passes through the vibration isolation table and is connected to the support shaft system via a flexible coupling. The support shaft system is connected to the shaft system to be tested via a flange. The other side of the shaft system to be tested is connected to the pressure plate. A preload loading module is connected to the pressure plate. The other side of the preload loading module is connected to the vertical plate. The magnetic gauge base is located inside the vertical plate.

[0005] The support shaft system includes a support spindle, support bearing A, spindle box and support bearing B. The support spindle is connected to the drive motor through a flexible coupling and passes through support bearing A, spindle box and support bearing B.

[0006] The shaft system to be tested includes a friction sensor, an eccentric plate, a bearing sleeve, a bearing to be tested, and a friction spindle. The bearing to be tested has a friction spindle at its center, a bearing sleeve outside the bearing to be tested, and an eccentric plate at the bottom of the bearing sleeve. The eccentric plate is the force measuring point of the friction force.

[0007] The magnetic base is adjustable in height and angle, and a friction sensor is installed on it. The friction sensor is in contact with the eccentric plate of the shaft system to be measured. By adjusting the magnetic base to switch the force measuring position, the friction torque of the shaft system in both forward and reverse rotation states can be measured separately.

[0008] The preload loading module includes a preload sensor, an insulating baffle A, a piezoelectric ceramic, an insulating baffle B, a conductive slip ring, and a preload bolt. The preload bolt passes through the center of the pressure plate, and the pressure plate is in close contact with the inner ring of the bearing to be tested. The preload bolt passes through the insulating baffle A, the piezoelectric ceramic, the insulating baffle B, the preload sensor, and the pressure plate in sequence, and is finally fixedly connected to the main shaft of the shaft system to be tested.

[0009] The piezoelectric ceramic forms a control loop with a DC power supply and a computer through a conductive slip ring. Under the control of the computer, the preload loading module accurately applies DC voltage to the piezoelectric ceramic and monitors the loading force value in real time through a high-precision preload sensor, thereby achieving accurate loading of the preload of the shaft system under test.

[0010] When the shaft system under test rotates, the frictional force is transmitted sequentially through the friction spindle, the inner and outer rings of the bearing under test, the bearing sleeve, and the eccentric plate to the high-precision friction force sensor. The force value measured by the friction force sensor is multiplied by the design value of the rotation radius of the shaft system under test to obtain the frictional torque of the shaft system under test.

[0011] The beneficial effects of this invention are: it achieves precise loading of preload during shaft friction torque measurement, and enables high-precision measurement of shaft friction torque under different preload conditions, avoiding errors caused by manual preload loading and providing a precise and quantifiable loading and control method; this invention can measure the forward and reverse friction torque of shafts of different sizes by adjusting the position and angle of the magnetic base; this invention has high detection accuracy and good stability, and can output the starting value, running value, and average running value of the friction torque of the shaft under test. This invention can systematically complete the measurement and mapping of friction torque of shafts under different preload conditions, establish a precise correlation model between preload and friction torque, and help break through a major bottleneck in shaft performance optimization. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the support shaft system structure of the present invention; Figure 3 This is a schematic diagram of the shaft system structure to be tested according to the present invention; Figure 4 This is a schematic diagram of the preload loading module structure of the present invention; In the diagram: 1. Test bench, 2. Vibration isolation table, 3. Drive motor, 4. Flexible coupling, 5. Support shaft system, 6. Flange, 7. Shaft system to be tested, 8. Pressure plate, 9. Preload loading module, 10. Vertical plate, 11. Magnetic base, 12. Support spindle, 13. Support bearing A, 14. Spindle box, 15. Support bearing B, 16. Friction sensor, 17. Eccentric plate, 18. Bearing sleeve, 19. Bearing to be tested, 20. Friction spindle, 21. Preload sensor, 22. Insulating baffle A, 23. Piezoelectric ceramic, 24. Insulating baffle B, 25. Conductive slip ring, 26. Preload bolt. Detailed Implementation

[0013] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. It should be noted that the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] Please see Figures 1-4A preload-loaded shaft friction torque measuring instrument includes a test bench 1, a vibration isolation table 2, a drive motor 3, a flexible coupling 4, a support shaft system 5, a flange 6, a shaft system to be tested 7, a pressure plate 8, a preload loading module 9, a vertical plate 10, and a magnetic gauge base 11. The vibration isolation table 2 is fixedly installed on the upper side of the test bench 1. The drive motor 3 is mounted on one side of the vibration isolation table 2. The shaft end of the drive motor 3 passes through the vibration isolation table 2 and is connected to the support shaft system 5 through the flexible coupling 4. The support shaft system 5 is connected to the shaft system to be tested 7 through the flange 6. The other side of the shaft system to be tested 7 is connected to the pressure plate 8. The preload loading module 9 is connected to the pressure plate 8. The other side of the preload loading module 9 is connected to the vertical plate 10. The magnetic gauge base 11 is located inside the vertical plate 10. The supporting shaft system 5 includes a supporting spindle 12, a supporting bearing A13, a spindle box 14, and a supporting bearing B15. The supporting spindle 12 is connected to the drive motor 3 via a flexible coupling 4, and passes through the supporting bearing A13, the spindle box 14, and the supporting bearing B15. The shaft system 7 to be tested includes a friction sensor 16, an eccentric plate 17, a bearing sleeve 18, a bearing to be tested 19, and a friction spindle 20. The friction spindle 20 is located at the center of the bearing to be tested 19, and a bearing sleeve 18 is located outside the bearing to be tested 19. An eccentric plate 17 is located at the bottom of the bearing sleeve 18. The eccentric plate 17 is the force measuring point of the friction sensor 16. The friction sensor 16 is installed above a magnetic base 11 with adjustable height and angle. By adjusting the magnetic base 11, the force measuring position can be switched to realize the separate measurement of friction torque in the forward and reverse rotation states of the shaft system. The preload loading module 9 includes a preload sensor 21, an insulating baffle A22, a piezoelectric ceramic 23, an insulating baffle B24, a conductive slip ring 25, and a preload bolt 26. The piezoelectric ceramic 23 forms a control loop with a DC power supply and a computer through the conductive slip ring 25. Under the control of the computer, the preload loading module 9 accurately applies a DC voltage to the piezoelectric ceramic 23 and monitors the loading force value in real time through the high-precision preload sensor 21 to achieve accurate loading of the preload of the shaft system under test. The preload bolt 26 passes through the center of the pressure plate 8, and the pressure plate 8 is in close contact with the inner ring of the bearing 19 under test. The preload bolt 26 passes through the insulating baffle A22, the piezoelectric ceramic 23, the insulating baffle B24, the preload sensor 21, and the pressure plate 8 in sequence, and is finally fixedly connected to the main shaft of the shaft system 7 under test. When the shaft system 7 under test rotates, the frictional force is transmitted sequentially through the friction spindle 20, the inner and outer rings of the bearing 19 under test, the bearing sleeve 18, and the eccentric plate 17 to the high-precision friction sensor 16. The force value measured by the friction sensor 16 is multiplied by the design value of the rotation radius of the shaft system 7 under test to obtain the frictional torque of the shaft system 7 under test.

[0015] When using the preload-loaded shaft friction torque measuring instrument of the present invention: connect the external power supply, install the shaft system 7 to be tested, press down the pressure plate 8, install and fix the preload loading module 9, tighten the preload bolt 26 and observe the reading of the preload sensor 21. When the reading of the preload sensor 21 just starts to increase from zero, it indicates that the axial clearance has been eliminated. Lock the preload loading module 9 and fix the upright plate 10. Adjust the magnetic base 11 to attach the friction sensor 16 to the reserved position on the eccentric plate 17. Then, set the experimental parameters such as preload, drive motor 3 rotation speed, and shaft system 7 size through the computer equipment. After setting, start the test. The computer equipment automatically controls the DC power output to load the preload. After loading to the specified value, the loading automatically stops. Then, the drive motor 3 runs at the set rotation speed. The data measured by the friction torque sensor is transmitted back to the computer equipment. After processing by the computer equipment, the shaft friction torque measurement result is obtained.

[0016] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0017] The parts of this invention not described in detail are prior art.

Claims

1. A preload-loaded shaft friction torque measuring instrument, comprising a test bench (1), a vibration isolation table (2), a drive motor (3), a flexible coupling (4), a support shaft system (5), a flange (6), a shaft system to be tested (7), a pressure plate (8), a preload loading module (9), a vertical plate (10), and a magnetic base (11), characterized in that: A vibration isolation table (2) is fixedly installed on the upper side of the test bench (1). A drive motor (3) is mounted on one side of the vibration isolation table (2). The shaft end of the drive motor (3) passes through the vibration isolation table (2) and is connected to the support shaft system (5) through a flexible coupling (4). The support shaft system (5) is connected to the shaft system to be tested (7) through a flange (6). The other side of the shaft system to be tested (7) is connected to a pressure plate (8). A pre-tightening loading module (9) is connected on the pressure plate (8). The other side of the pre-tightening loading module (9) is connected to a vertical plate (10). The magnetic gauge base (11) is set on the inner side of the vertical plate (10).

2. The preload-precision loading shaft friction torque measuring instrument according to claim 1, characterized in that: The support shaft system (5) includes a support spindle (12), a support bearing A (13), a spindle box (14), and a support bearing B (15). The support spindle (12) is connected to the drive motor (3) through a flexible coupling (4). The support spindle (12) passes through the support bearing A (13), the spindle box (14), and the support bearing B (15).

3. The preload-precision loading shaft friction torque measuring instrument according to claim 1, characterized in that: The shaft system to be tested (7) includes an eccentric plate (17), a bearing sleeve (18), a bearing to be tested (19), and a friction spindle (20). The bearing to be tested (19) has a friction spindle (20) at its center, a bearing sleeve (18) is provided outside the bearing to be tested (19), and an eccentric plate (17) is provided at the bottom of the bearing sleeve (18). The eccentric plate (17) is the force measuring point of friction.

4. The preload-precision loading shaft friction torque measuring instrument according to claim 1, characterized in that: The magnetic base (11) is adjustable in height and angle, and a friction sensor (16) is installed on it. The friction sensor (16) is in contact with the eccentric plate (17) of the shaft system (7) to be measured. By adjusting the magnetic base (11) to switch the force measuring position, the friction torque of the shaft system in both forward and reverse states can be measured separately.

5. The preload-precision loading shaft friction torque measuring instrument according to claim 1, characterized in that: The preload loading module (9) includes a preload sensor (21), an insulating baffle A (22), a piezoelectric ceramic (23), an insulating baffle B (24), a conductive slip ring (25), and a preload bolt (26). The preload bolt (26) passes through the center of the pressure plate (8). The pressure plate (8) is in close contact with the inner ring of the bearing of the shaft system (7) to be tested. The preload bolt (26) passes through the insulating baffle A (22), the piezoelectric ceramic (23), the insulating baffle B (24), the preload sensor (21), and the pressure plate (8) on both sides in sequence, and is finally fixedly connected to the main shaft of the shaft system (7) to be tested.

6. The preload-precision loading shaft friction torque measuring instrument according to claim 5, characterized in that: The piezoelectric ceramic (23) forms a control loop with the DC power supply and computer through the conductive slip ring (25). Under the control of the computer, the preload loading module (9) accurately applies DC voltage to the piezoelectric ceramic (23) and monitors the loading force value in real time through the high-precision preload sensor (21) to achieve accurate loading of the preload force of the shaft system (7) under test.

7. The preload-precision loading shaft friction torque measuring instrument according to claim 3, characterized in that: When the shaft system (7) to be tested rotates, the friction force is transmitted sequentially through the friction spindle (20), the inner and outer rings of the bearing (19) to be tested, the bearing sleeve (18), and the eccentric plate (17) to the high-precision friction sensor (16). The force value measured by the friction sensor (16) is multiplied by the design value of the rotation radius of the shaft system (7) to be tested to obtain the friction torque of the shaft system (7).

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