Arc friction surface clamping force testing device and method

Abstract

The application belongs to a clamping force testing device and method, and aims at solving the technical problem that there is no effective clamping force testing method at present when the pressure steel pipe is processed and tested, and the clamping force needs to be tested to meet the clamping requirement and not to damage the pressure steel pipe. The application provides a circular arc friction surface clamping force testing device and method, which can support the pressure steel pipe to be tested through a supporting assembly, limit the pressure steel pipe to be tested through the upper die and the lower die in the clamping assembly, fix the upper die and the lower die through a screw rod, and tighten the threaded tool at the end of the pressure steel pipe to be tested through a tightening assembly. When the pressure steel pipe to be tested does not rotate with the threaded tool, the clamping force of the pressure steel pipe to be tested can be measured according to the length of the screw rod outer spring and the free length of the spring. The testing device of the application has a simple and compact structure, and the clamping force of the pressure steel pipe to be tested can be obtained in a simple way through mutual cooperation.

Description

Technical Field

[0001] The present invention relates to a clamping force testing device and method, and in particular to a clamping force testing device and method for an arc friction surface. Background Art

[0002] Penstocks are commonly used for fluid transportation and deep burial of hazardous waste, particularly high-strength, thin-walled penstocks. During processing, these thin-walled penstocks must be clamped and secured, as well as during pressure and airtightness testing.

[0003] When clamping penstocks, pneumatic or hydraulic chucks are typically used. However, the friction force when clamping the penstock's arc surface is difficult to determine. To ensure reliable clamping, the chuck or clamping mechanism is often oversized, making it easy for a "big horse pulling a small cart" situation to occur. Furthermore, given the specific material of the arc friction surface, the positive pressure on the friction surface is very high, which can easily cause the penstock's arc surface to deform under pressure. This deformation is particularly severe for thin-walled penstocks. To prevent deformation, chucks with lower clamping force are typically used, but this can cause the penstock to rotate due to loose clamping. Consequently, materials with high friction coefficients, such as cotton wool or felt, are manually inserted into the friction surface, often with unsatisfactory results.

[0004] In summary, thin-walled penstocks often produce defective products during processing and testing. This is due to the difficulty in measuring the friction force on the arc surface of thin-walled penstocks. Therefore, in actual use, to ensure that thin-walled penstocks are clamped and prevented from rotating, sufficient friction force must be provided on the arc surface, while also overcoming the problem of deformation caused by excessive positive pressure. Therefore, it is necessary to test the clamping force to ensure that it meets the clamping requirements without damaging the penstock. However, no effective clamping force testing method has yet been developed. Summary of the Invention

[0005] The present invention aims to solve the technical problem that during the processing and testing of pressure steel pipes, in order to ensure that the clamping force can meet the clamping requirements without causing damage to the pressure steel pipes, the clamping force needs to be tested, but there is a lack of effective clamping force testing methods. The present invention provides a circular arc friction surface clamping force testing device and method.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A circular arc friction surface clamping force testing device is special in that it includes a frame assembly, a support assembly, a clamping assembly, a tightening assembly, a limiter and a drive assembly;

[0008] The rack assembly is provided with a guide rail; the tightening assembly is installed on the guide rail and connected with the output end of the driving assembly; the clamping assembly is installed on the guide rail and matched with the guide rail; the driving assembly is installed on the rack assembly and used to drive the tightening assembly to move along the guide rail;

[0009] The limiting member is installed on the guide rail or the rack assembly and located on both sides of the supporting assembly, and used to limit the position of the supporting assembly on the guide rail;

[0010] The clamping assembly comprises an upper die, a lower die, a spring, a gasket and two screw rods; the lower die is installed on the supporting assembly; the upper die and the lower die are connected through the screw rods; the outer peripheral surface of the cavity formed by the inner surface of the upper die and the inner surface of the lower die is matched with the circumferential outer contour of the pressure steel pipe to be measured; the inner surface of the upper die, the inner surface of the lower die and the supporting surface of the supporting assembly simultaneously contact the surface of the pressure steel pipe to be measured; the gasket is installed at one end of the screw rod; the spring is sleeved outside the screw rod, one end of the spring is connected with or abuts against the gasket, and the other end is connected with or abuts against the upper surface of the connection between the upper die and the lower die;

[0011] The tightening assembly comprises a tightening driving unit, a tightening jaw and a rotating disc; the rotating disc is installed on the output end of the tightening driving unit and used to drive the rotating disc to rotate through the tightening driving unit; the tightening jaw is installed on the rotating disc; the cavity surrounded by the rotating disc, the upper die and the lower die is coaxially arranged.

[0012] Further, the tightening assembly further comprises a rotating zero reset proximity switch and a compression zero reset proximity switch installed on the tightening driving unit;

[0013] The rotating disc is provided with a rotating sensing sheet and an axial compression sensing sheet;

[0014] The detection end of the rotating zero reset proximity switch faces the rotating path of the rotating sensing sheet along with the rotation of the rotating disc, and when the detection end of the rotating zero reset proximity switch directly faces the rotating sensing sheet, the tightening jaw directly faces the flange opening on the end face thread tool of the pressure steel pipe to be measured;

[0015] The axial compression sensing sheet is located below the compression zero reset proximity switch, and when the detection end of the compression zero reset proximity switch directly faces the edge of the end of the axial compression sensing sheet away from the rotating disc, the tightening jaw is clamped in the flange opening on the end face thread tool of the pressure steel pipe to be measured;

[0016] The rotating zero reset proximity switch and the compression zero reset proximity switch are electrically connected with the driving motor of the tightening driving unit.

[0017] Further, the upper die comprises an upper die body and upper die connecting seats connected to two sides of the upper die body; the lower die comprises a lower die body and lower die connecting seats connected to two sides of the lower die body; the inner surfaces of the upper die body and the lower die body together form a cavity outer periphery surface which is adapted to the peripheral contour of the pressure steel pipe to be tested;

[0018] The four screws pass through the upper die connecting seats and the lower die connecting seats and are respectively located at four corners of the upper die connecting seats and the lower die connecting seats; the other ends of the screws are provided with nuts which abut against the end surfaces of the lower die connecting seats away from the upper die connecting seats.

[0019] Further, the lower die body is provided with two lower die bodies which are arranged in parallel and correspond to two ends of the upper die body respectively, and the two lower die bodies are connected through a connecting plate.

[0020] Further, the end of the screw close to the gasket is connected with a ring lug for the external lever to rotate the screw;

[0021] A handle is installed on the outside of the upper die connecting seat.

[0022] Further, the support assembly comprises two V-shaped supports arranged in parallel;

[0023] The V-shaped supports are arranged on the mounting plate, and the bottom of the mounting plate is provided with first sliding blocks which are adapted to the guide rails; the two sides of each first sliding block along the extension direction of the guide rail are provided with limiting members;

[0024] The lower die is located between the two V-shaped supports.

[0025] Further, a gasket plate for adjusting the height is installed on the support surface of the V-shaped support;

[0026] The inner surfaces of the upper die body and the lower die body are both provided with silica gel plates.

[0027] Further, the driving assembly comprises a servo motor, a driving sprocket, a driven sprocket, a ball screw and an idler wheel;

[0028] The servo motor is installed on the rack assembly;

[0029] The driving sprocket is installed on the output end of the servo motor, and is used to drive the driving sprocket to rotate through the servo motor; the driving sprocket and the driven sprocket are connected through a synchronous belt; one end of the ball screw is connected with the driven sprocket, and the other end is installed on the rack assembly; the idler wheel is installed on the shell of the servo motor through an idler connecting seat, and abuts against the synchronous belt, and is used to tighten the synchronous belt;

[0030] The tightening driving unit is installed on a tightening frame, and the bottom of the tightening frame is provided with a second sliding block and a screw nut.

[0031] The screw nut is installed on the ball screw, and the second sliding block is installed on the guide rail.

[0032] Furthermore, the tightening drive unit includes a mounting bracket, and a telescopic tightening device and a sleeve mounted on the mounting bracket;

[0033] The output end of the telescopic tightening device passes through the mounting bracket, the rotating disk is mounted on the output end of the telescopic tightening device, the sleeve is sleeved outside the output end of the telescopic tightening device, and the rotation zero proximity switch and the compression zero proximity switch are mounted on the sleeve through the switch mounting bracket;

[0034] The mounting bracket is mounted on the tightening frame.

[0035] The present invention also provides a method for testing the clamping force of an arc friction surface, which is based on the above-mentioned device for testing the clamping force of an arc friction surface. The method is special in that it includes the following steps:

[0036] S1, placing the pressure steel pipe to be tested on the support assembly and the lower die;

[0037] S2, placing the upper die on the lower die, and inserting the screw into the connection between the upper die and the lower die;

[0038] S3, install the spring and gasket on the screw and measure the free length H0 of each spring i ; i is an integer greater than or equal to 2, indicating the serial number of the spring;

[0039] S4, continue to tighten the screw several times, and after each tightening of the screw, drive the threaded tooling at the end of the pressure steel pipe to be tested to rotate in the tightening direction through the tightening assembly. If the pressure steel pipe to be tested rotates accordingly, continue to tighten the screw until the pressure steel pipe stops rotating. Measure the length of the spring at this time and record it as H1 i Otherwise, measure the length of the spring at this time and record it as H1 i ;

[0040] S5, calculate the clamping force f of each spring by the following formula i :

[0041] f i =K i (H0 i -H1 i )

[0042] Among them, K i represents the spring constant of the i-th spring;

[0043] S6, the clamping force F of the penstock to be tested is obtained by the following formula:

[0044] F=K0(f1+f2+…+fn )

[0045] Where n is the total number of springs and K0 is the safety factor.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The present invention provides a circular arc friction surface clamping force testing device, which can support the pressure steel pipe to be tested through a supporting assembly, limit the pressure steel pipe to be tested through the upper mold and the lower mold in the clamping assembly, and use a screw to fix the upper mold and the lower mold. At the same time, the threaded tooling at the end of the pressure steel pipe to be tested can be tightened by the tightening assembly. When the pressure steel pipe to be tested just does not rotate with the threaded tooling, the clamping force of the pressure steel pipe to be tested can be measured in combination with the length of the spring outside the screw at this time and the free length of the spring. The testing device of the present invention has a simple and compact structure, and can obtain the clamping force of the pressure steel pipe to be tested in a simple manner by cooperating with each other.

[0048] 2. The tightening assembly of the present invention is also provided with a rotation return to zero proximity switch and a compression return to zero proximity switch, which facilitates confirmation of the rotation zero position and the compression zero position when the tightening assembly is working, so that the testing device of the present invention can realize automated testing.

[0049] 3. In the present invention, the end of the screw is connected with a ring ear, which is convenient for tightening or loosening the screw using an external tool.

[0050] 4. In the present invention, a handle is installed on the upper mold connecting base to facilitate the disassembly and assembly of the upper mold body and the upper mold connecting base during testing.

[0051] 5. The drive assembly of the present invention adopts a ball screw and nut driving method, and the driving is stable, reliable and easy to implement.

[0052] 6. The present invention provides a method for testing the clamping force of an arc friction surface. Using the above-mentioned testing device, it is only necessary to measure the length of each spring to obtain the clamping force generated by each spring. Combined with the safety factor during clamping, the clamping force of the pressure steel pipe to be tested can be tested and obtained. The principle used is to measure the positive pressure of the friction surface to measure the minimum positive pressure required to overcome the rotation. In the field of processing and testing of the pressure steel pipe to be tested, a basis is provided for the design and selection of the clamping mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a structural schematic diagram of an embodiment of a circular arc friction surface clamping force testing device of the present invention;

[0054] Figure 2 For the present invention Figure 1 Schematic diagram of the structure of the middle frame assembly and drive assembly;

[0055] Figure 3 For the present invention Figure 2Schematic diagram of the structure of the middle drive component;

[0056] Figure 4 For the present invention Figure 1 Schematic diagram of the structure of the tightening component;

[0057] Figure 5 For the present invention Figure 1 Schematic diagram of the structure of the middle V-shaped support;

[0058] Figure 6 For the present invention Figure 1 Schematic diagram of the structure of the clamping assembly;

[0059] Figure 7 For the present invention Figure 6 Left view of .

[0060] Among them: 1- rack assembly, 101- mounting frame, 102- guide rail, 103- foot plate, 2- support assembly, 201- pad, 202- V-shaped support, 203- mounting plate, 204- first slider, 3- clamping assembly, 301- screw, 302- gasket, 303- spring, 304- foot seat, 305- nut, 306- lower die, 3061- lower die body, 3062- lower die connecting seat, 307- upper die, 3071- upper die body, 3072- upper die connecting seat, 308- connecting plate, 309- handle, 310- ring ear, 4- tightening assembly, 401- tightening drive unit, 402- mounting bracket, 403- switch mounting bracket, 404-Compression zeroing proximity switch, 405-Rotation zeroing proximity switch, 406-Tightening claw, 407-Rotating disk, 408-Tightening frame, 409-Second slider, 410-Screw nut, 411-Rotational sensing plate, 412-Axial compression sensing plate, 413-Telescopic tightening device, 414-Sleeve, 5-Limiting piece, 6-Threaded tooling, 7-Drive assembly, 701-Ball screw, 702-Servo motor, 703-Synchronous belt, 704-Idler connecting seat, 705-Motor mounting seat, 706-Idler, 707-Reducer, 708-Reducer mounting seat, 709-Active synchronous wheel, 710-Driven synchronous wheel, 8-Pressure steel pipe to be tested. DETAILED DESCRIPTION

[0061] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0062] The test of the clamping force of the circular arc friction surface is carried out in the case that the friction area and the friction material are constant, the compression length of the spring 303 is measured by adopting the spring 303 in compression, and the compression length of the spring 303 is calculated according to the Hooke's law: y=kx, wherein y represents the elastic force, k represents the stiffness coefficient of the spring 303, and x represents the length change of the spring 303. The compression force of the spring 303 is calculated, and the test of the clamping force of the circular arc friction surface is simplified to the normal pressure test of the circular arc friction surface.

[0063] As shown in Figure 1 , the clamping force test device of the circular arc friction surface of the application comprises a rack assembly 1, a support assembly 2, a clamping assembly 3, a tightening assembly 4, a limiting piece 5 and a driving assembly 7, two parallel guide rails 102 are installed on the rack assembly 1, the support assembly 2 is installed on the guide rail 102, the limiting piece 5 is installed on the guide rail 102 and located on both sides of the installation position of the support assembly 2 on the guide rail 102, used to limit the position of the support assembly 2 on the guide rail 102, the pressure steel pipe 8 to be tested is placed on the support assembly 2 and clamped by the clamping assembly 3, the tightening assembly 4 is installed on the guide rail 102 and driven to move along the guide rail 102 by the driving assembly 7, and the tightening assembly 4 is used to tighten or loosen the threaded tool 6 at the end of the pressure steel pipe 8 to be tested.

[0064] As shown in Figure 2 , the rack assembly 1 is installed on the factory floor through the foot plate 103 at the bottom of the installation frame 101, the specific number of the foot plate 103 can be adjusted according to the actual needs, such as the length of the installation frame 101, and the foot plate 103 is symmetrically arranged on both sides of the installation frame 101. Two parallel guide rails 102 are installed on the top of the installation frame 101, four limiting pieces 5 are installed on the middle of each guide rail 102 on the installation frame 101, the limiting pieces 5 on one guide rail 102 are arranged one by one corresponding to the limiting pieces 5 on the other guide rail 102, and the installation plate 203 of the V-shaped support 202 is located between the two limiting pieces 5 on the two guide rails, and the installation position of the V-shaped support 202 on the guide rail 102 is limited by the limiting pieces 5.

[0065] As shown in Figure 2 and Figure 3The driving assembly 7 is installed on the mounting frame 101, the driving assembly 7 comprises a servo motor 702, a driving sprocket 709, a driven sprocket 710, a ball screw 701 and an idler 706, the servo motor 702 is installed on the mounting frame 101, the driving sprocket 709 is installed on the output end of a speed reducer 707, the servo motor 702 drives the speed reducer 707, thereby driving the driving sprocket 709 to rotate, the speed reducer 707 is installed on the mounting frame 101 through a speed reducer mounting seat 708. The driving sprocket 709 and the driven sprocket 710 are connected through a synchronous belt 703, the driving sprocket 709, the driven sprocket 710 and the synchronous belt 703 form a synchronous belt transmission mechanism, one end of the ball screw 701 is connected with the driven sprocket 710, and the other end is installed on the rack assembly 1, the ball screw 701 is driven to rotate through the synchronous belt transmission mechanism. A motor mounting seat 705 is arranged on the shell of the servo motor 702, the idler 706 is installed on the motor mounting seat 705 through an idler connecting seat 704, the motor mounting seat 705 is installed on the mounting frame 101, the idler 706 abuts against the synchronous belt 703, and the synchronous belt 703 is used for tensioning the synchronous belt 703.

[0066] As Figure 4The tightening assembly 4 includes a tightening drive unit 401, a tightening claw 406, and a rotating disk 407. The tightening drive unit 401 includes a mounting bracket 402, and a telescopic tightening device 413 and a sleeve 414 mounted on the mounting bracket 402. The output end of the telescopic tightening device 413 is set through the mounting bracket 402, and the rotating disk 407 is mounted on the output end of the telescopic tightening device 413. The telescopic tightening device 413 drives the rotating disk 407 to rotate. In addition, the telescopic tightening device 413 can adopt an existing tightening device. The output end of the telescopic tightening device 413 can be compressed relative to the outer shell of the telescopic tightening device 413. The telescopic tightening device 413 provides torque to the threaded tooling 6 on the end face of the pressure steel pipe 8 to be tested. The tightening claw 406 is installed on the rotating disk 407. The tightening claw 406, the cavity surrounded by the upper mold 307 and the lower mold 306, and the support assembly 2 are coaxially arranged. When the tightening claw 406 moves on the guide rail 102 with the telescopic tightening device 413 to the threaded tooling 6 at the end face of the pressure steel pipe 8 to be tested, the tightening claw 406 is facing the end face of the threaded tooling 6. In this embodiment, the specific number of claws in the tightening claw 406 is three, which are evenly distributed along the circumference of the rotating disk 407. In other embodiments of the present invention, the specific number of claws can also be adjusted according to the actual situation of the flange notch on the threaded tooling 6. The sleeve 414 is sleeved on the outside of the output end of the telescopic tightening device 413, and the rotation zero proximity switch 405 and the compression zero proximity switch 404 are installed on the sleeve 414 through the switch mounting bracket 403. The mounting bracket 402 is installed on the tightening frame 408. The second slider 409 and the screw nut 410 are installed at the bottom of the tightening frame 408. The screw nut 410 is installed on the ball screw 701, and the second slider 409 is installed on the guide rail 102. The ball screw 701 rotates under the drive of the servo motor 702, and can drive the screw nut 410 to move linearly on the ball screw 701, so that the tightening frame 408 drives the entire tightening assembly 4 to move along the guide rail 102 toward or away from the pressure steel pipe 8 to be tested.

[0067] like Figure 1 and Figure 5 The support assembly 2 includes two parallel V-shaped supports 202, which are arranged on a mounting plate 203. A first slider 204 adapted to the guide rail 102 is provided at the bottom of the mounting plate 203. Each first slider 204 is provided with a limiting member 5 on both sides of the extension direction of the guide rail 102. After the V-shaped support 202 is installed on the guide rail 102, the installation position of the V-shaped support 202 can be limited by the limiting members 5 on both sides of the first slider 204. An adjustment pad 201 is provided on the supporting surface of the V-shaped support 202, and the pad 201 can be made of silicone material.

[0068] like Figure 6The clamping assembly 3 is a key structure of the circular-arc friction surface clamping force testing device. Four foot supports 304 are arranged on the inner side of the V-shaped support 202, so that the lower die 306 is located between the two V-shaped supports 202. The upper die 307 comprises an upper die body 3071 and upper die connecting seats 3072 connected to the two sides of the upper die body 3071. The lower die 306 comprises two parallel lower die bodies 3061 and lower die connecting seats 3062 connected to the two sides of the lower die bodies 3061. The two lower die bodies 3061 are respectively located at the two ends of the upper die body 3071 and are connected through a connecting plate 308. The two lower die bodies 3061 are respectively connected to one foot support 304. The inner surfaces of the upper die body 3071 and the two lower die bodies 3061 together form a surface which is matched with the circumferential outer contour of the pressure steel pipe 8 to be tested, and the pressure steel pipe 8 to be tested is clamped by the upper die body 3071 and the two lower die bodies 3061. The upper die connecting seats 3072 and the lower die connecting seats 3062 are connected through four screw rods 301. The four screw rods 301 are respectively located at the four corners of the clamping assembly 3, pass through the two ends of the upper die connecting seats 3072 on the two sides of the upper die body 3071 and the lower die connecting seats 3062 on the two sides of the two lower die bodies 3061, and the screw rods 301 can be coarse thread screw rods, so as to avoid the situation that the screw threads are locked and the screw rods 301 cannot be disassembled during clamping. The screw rods 301 are respectively provided with annular gaskets 302 at one end and nuts 305 at the other end. The nuts 305 abut against the end surfaces of the lower die connecting seats 3062 away from the upper die connecting seats 3072, so that the screw rods 301 can connect the upper die connecting seats 3072 and the lower die connecting seats 3062. Springs 303 are sleeved outside the screw rods 301. One end of each spring 303 is connected to or abuts against the gasket 302, and the other end is connected to or abuts against the connection between the upper die 307 and the lower die 306. With the screw rods 301 being screwed between the upper die connecting seats 3072 and the lower die connecting seats 3062, the springs 303 are compressed. The springs 303 are generally rectangular springs. The end of each screw rod 301 close to the gasket 302 is connected with a ring lug 310. A force lever is inserted into the ring lug 310 to rotate, so as to tighten the screw rods 301 and compress the springs 303. When the pressure steel pipe 8 to be tested is clamped, a dead wrench is used to fix the nuts 305. The upper die connecting seats 3072 are provided with handles 309 on the outer sides. The inner surfaces of the upper die body 3071 and the lower die bodies 3061 can be bonded with silica gel plates with high friction coefficients. Since the upper die body 3071 is heavy, the handles 309 are arranged on the two sides to facilitate manual carrying. The silica gel plates are bonded with the circular-arc surfaces of the inner surfaces of the upper die body 3071 and the lower die bodies 3061 through special glue. When the circular-arc surfaces are bonded with silica gel, first, the metal bonding surfaces are roughened to increase the adhesion of the special glue. Then, the circular-arc surfaces are preheated and kept warm in an oven. After bonding, the silica gel is fixed by a profiling tool. Finally, the special glue is cured in the oven.The length of the spring 303 can be measured using a depth gauge. The compression of the spring 303 can be obtained by the length difference before and after compression of the spring 303. Combined with Hooke's theorem, the clamping force of the clamping assembly 3 can be calculated.

[0069] Based on the aforementioned testing device, the present invention proposes a method for testing the clamping force of an arc friction surface, providing a method for testing the clamping force required during the production and testing of the pressure steel pipe 8 to be tested. During the clamping force test, the upper die body 3071 and the lower die body 3061 are clamped together, and the screw 301 is tightened and fed to increase the clamping force. The relationship between the action force and the reaction force is used to calculate the clamping force through the compression of the spring. The specific testing method is as follows:

[0070] (1) Manually install the foot 304 on the inner side of the V-shaped support 202, install the lower mold connecting seat 3062 on the foot 304, and connect the lower mold connecting seats 3062 corresponding to the two lower mold bodies 3061 using a connecting plate 308;

[0071] (2) Manually hoist the pressure steel pipe 8 to be tested with threaded fixtures 6 at both ends and place it centrally on the V-shaped support 202;

[0072] (3) Manually hoist the upper mold body 3071 and the upper mold connecting base 3072 and place them on the lower mold body 3061 and the lower mold connecting base 3062, and pass the four screws 301 through the upper mold connecting base 3072 and the lower mold connecting base 3062 respectively;

[0073] (4) Manually fit the spring 303 and the washer 302 onto the screw 301 and tighten the nut 305 at the bottom of the screw 301;

[0074] (5) Manually measure the free length of spring 303 using a depth gauge and record it as H0 i ; i is an integer greater than or equal to 2, indicating the serial number of the spring 303;

[0075] (6) Manually insert the lever into the ring ear 310, apply force and rotate it to feed it, and use the depth gauge to measure the length of the spring 303 after compression again;

[0076] (7)Servo motor 702 drives ball screw 701, thereby driving tightening assembly 4 to approach threaded tooling 6 on the end face of pressure steel pipe 8 under test. At the same time, telescopic tightening device 413 drives rotary disc 407 to rotate, and rotary zeroing proximity switch 405 detects rotary inductive sheet 411, indicating that each jaw in tightening jaw 406 is respectively opposite flange aperture on threaded tooling 6 on the end face of pressure steel pipe 8 under test, and telescopic tightening device 413 temporarily stops driving rotary disc 407 to rotate, and tightening assembly 4 continues to approach threaded tooling 6 on the end face of pressure steel pipe 8 under test, and each jaw in tightening jaw 406 is respectively inserted into flange aperture of threaded tooling 6, and when axial compression proximity switch 404 detects axial compression inductive sheet 412, it indicates that tightening jaw 406 is clamped in flange aperture on threaded tooling 6 on the end face of pressure steel pipe 8 under test, and rotary disc 407 is attached to threaded tooling 6, and tightening assembly 4 no longer moves towards threaded tooling 6 on the end face of pressure steel pipe 8 under test. Telescopic tightening device 413 drives rotary disc 407 to rotate, and if pressure steel pipe 8 under test does not rotate, it indicates that the friction generated by the clamping force is sufficient to overcome the rotation of pressure steel pipe 8 under test, and if pressure steel pipe rotates, continue to rotate screw 301 to tighten, and observe whether pressure steel pipe 8 under test rotates or not, until it does not move, and measure and record the length H1 of spring 303 after compression i .

[0077] (8) Data processing

[0078] According to Hooke's law y=kx, the clamping force f generated by the compression of a single spring 303 is calculated i :

[0079] f i =K i (H0 i -H1 i )

[0080] Wherein, K i represents the stiffness coefficient of the i-th spring 303;

[0081] A total of 4 springs are used during testing, and the safety factor K0=1.2, so the total clamping force F of pressure steel pipe 8 under test is:

[0082] F=K0(f1+f2+…+f n )

[0083] Wherein, n represents the total number of springs 303, and K0 represents the safety factor.

[0084] After testing, the final clamping force F is used as a basis to select the clamping force of the clamping mechanism.

[0085] The above merely describes the preferred embodiments of the present application, and is not used to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A device for testing the clamping force of an arc friction surface, characterized by: It comprises a frame assembly (1), a support assembly (2), a clamping assembly (3), a tightening assembly (4), a position limiting member (5) and a driving assembly (7); A guide rail (102) is installed on the frame assembly (1); the tightening assembly (4) is installed on the guide rail (102) and is connected to the output end of the driving assembly (7); the clamping assembly (3) is installed on the guide rail (102) and is adapted to the guide rail (102); the driving assembly (7) is installed on the frame assembly (1) and is used to drive the tightening assembly (4) to move along the guide rail (102); The limiting member (5) is installed on the guide rail (102) or the frame assembly (1) and is located on both sides of the support assembly (2) to limit the position of the support assembly (2) on the guide rail (102); The clamping assembly (3) comprises an upper die (307), a lower die (306), a spring (303), a gasket (302) and two screws (301); the lower die (306) is mounted on the supporting assembly (2), the upper die (307) and the lower die (306) are connected via screws, and the outer peripheral surface of the cavity formed by the inner surface of the upper die (307) and the inner surface of the lower die (306) is adapted to the circumferential outer contour of the pressure steel pipe (8) to be tested. The inner surface of the upper die (307), the inner surface of the lower die (306) and the supporting surface of the supporting assembly (2) are in contact with the surface of the pressure steel pipe (8) to be tested at the same time; the gasket (302) is installed on one end of the screw (301); the spring (303) is sleeved on the outside of the screw (301), one end of the spring (303) is connected to or abuts against the gasket (302), and the other end is connected to or abuts against the upper surface of the connection between the upper die (307) and the lower die (306); The tightening assembly (4) comprises a tightening drive unit (401), a tightening claw (406) and a rotating disk (407); the rotating disk (407) is mounted on the output end of the tightening drive unit (401) and is used to drive the rotating disk (407) to rotate through the tightening drive unit (401); the tightening claw (406) is mounted on the rotating disk (407); and a cavity enclosed by the rotating disk (407), the upper die (307) and the lower die (306) is coaxially arranged.

2. The arc friction surface clamping force testing device according to claim 1, characterized in that: The tightening assembly (4) further comprises a rotation return-to-zero proximity switch (405) and a compression return-to-zero proximity switch (404) mounted on the tightening drive unit (401); The rotating disk (407) is provided with a rotation sensing plate (411) and an axial compression sensing plate (412); The detection end of the rotation return to zero proximity switch (405) faces the rotation path of the rotation sensor plate (411) along the rotation of the rotating disk (407), and when the detection end of the rotation return to zero proximity switch (405) faces the rotation sensor plate (411), the tightening claw (406) faces the flange notch on the end face threaded fixture (6) of the pressure steel pipe (8) to be tested; The axial compression sensing piece (412) is located below the compression return-to-zero proximity switch (404), and when the detection end of the compression return-to-zero proximity switch (404) is facing the edge of the axial compression sensing piece (412) away from the end of the rotating disk (407), the clamping claw (406) is tightened into the flange notch on the end face threaded tooling (6) of the pressure steel pipe (8) to be tested to complete the clamping; The rotation return-to-zero proximity switch (405) and the compression return-to-zero proximity switch (404) are both electrically connected to the drive motor of the tightening drive unit (401).

3. The arc friction surface clamping force testing device according to claim 2, characterized in that: The upper die (307) includes an upper die body (3071) and an upper die connecting seat (3072) connected to both sides of the upper die body (3071); the lower die (306) includes a lower die body (3061) and a lower die connecting seat (3062) connected to both sides of the lower die body (3061); the outer peripheral surface of the cavity formed by the inner surface of the upper die body (3071) and the inner surface of the lower die body (3061) is adapted to the circumferential outer contour of the pressure steel pipe (8) to be tested; Four screw rods (301) are provided, and the four screw rods (301) all pass through the upper die connecting seat (3072) and the lower die connecting seat (3062), and are respectively located at the four corners of the upper die connecting seat (3072) and the lower die connecting seat (3062); a nut (305) is installed at the other end of the screw rod (301), and the nut (305) abuts against the end surface of the lower die connecting seat (3062) away from the upper die connecting seat (3072).

4. The arc friction surface clamping force testing device according to claim 3, characterized in that: There are two lower mold bodies (3061), which are arranged parallel to each other and are respectively located at the two ends of the upper mold body (3071). The two lower mold bodies (3061) are connected via a connecting plate (308).

5. The arc friction surface clamping force testing device according to claim 4, characterized in that: The end of the screw rod (301) close to the gasket (302) is connected with a ring ear (310) for inserting an external lever into the rotating screw rod (301); A handle (309) is installed on the outer side of the upper mold connecting seat (3072).

6. The arc friction surface clamping force testing device according to claim 5, characterized in that: The support assembly (2) comprises two V-shaped supports (202) arranged in parallel; The V-shaped support (202) is arranged on the mounting plate (203), and a first slider (204) adapted to the guide rail (102) is provided at the bottom of the mounting plate (203); each first slider (204) is provided with the limiting member (5) on both sides along the extension direction of the guide rail (102); The lower mold (306) is located between the two V-shaped supports (202).

7. The arc friction surface clamping force testing device according to claim 6, characterized in that: A pad (201) for adjusting the height is installed on the supporting surface of the V-shaped support (202); A silicone plate is provided on the inner surface of the upper mold body (3071) and the inner surface of the lower mold body (3061).

8. The arc friction surface clamping force testing device according to claim 7, characterized in that: The driving assembly (7) includes a servo motor (702), an active synchronous wheel (709), a driven synchronous wheel (710), a ball screw (701) and an idler wheel (706); The servo motor (702) is mounted on the frame assembly (1); The active synchronous wheel (709) is mounted on the output end of the servo motor (702) and is used to drive the active synchronous wheel (709) to rotate through the servo motor (702). The active synchronous wheel (709) and the driven synchronous wheel (710) are connected through a synchronous belt (703). One end of the ball screw (701) is connected to the driven synchronous wheel (710), and the other end is mounted on the frame assembly (1). The idler wheel (706) is mounted on the housing of the servo motor (702) through an idler wheel connecting seat (704). The idler wheel (706) is against the synchronous belt (703) and is used to tighten the synchronous belt (703). The tightening drive unit (401) is installed on a tightening frame (408), and a second slider (409) and a lead screw nut (410) are installed at the bottom of the tightening frame (408); The screw nut (410) is mounted on the ball screw (701), and the second slider (409) is mounted on the guide rail (102).

9. The arc friction surface clamping force testing device according to claim 8, characterized in that: The tightening drive unit (401) comprises a mounting bracket (402), and a telescopic tightening device (413) and a sleeve (414) mounted on the mounting bracket (402); The output end of the telescopic tightening device (413) passes through the mounting bracket (402), the rotating disk (407) is mounted on the output end of the telescopic tightening device (413), the sleeve (414) is sleeved on the outside of the output end of the telescopic tightening device (413), and the rotation return-to-zero proximity switch (405) and the compression return-to-zero proximity switch (404) are mounted on the sleeve (414) through the switch mounting bracket (403); The mounting bracket (402) is mounted on a tightening frame (408).

10. A method for testing the clamping force of an arc friction surface, based on the device for testing the clamping force of an arc friction surface according to any one of claims 1 to 9, characterized in that: The following steps are involved: S1, placing the pressure steel pipe (8) to be tested on the support assembly (2) and the lower mold (306); S2, placing the upper mold (307) on the lower mold (306), and inserting the screw (301) into the connection between the upper mold (307) and the lower mold (306); S3, install the spring (303) and the washer (302) on the screw (301), and measure the free length H0 of each spring (303) i ; i is an integer greater than or equal to 2, indicating the serial number of the spring (303); S4, continue to tighten the screw (301) several times, and after each tightening of the screw (301), drive the threaded tool (6) at the end of the pressure steel pipe (8) to be tested to rotate in the tightening direction through the tightening component (4). If the pressure steel pipe (8) to be tested rotates accordingly, continue to tighten the screw (301) until the pressure steel pipe (8) to be tested stops rotating. Measure the length of the spring (303) at this time and record it as H1 i Otherwise, measure the length of the spring (303) at this time and record it as H1 i ; S5, calculate the clamping force f of each spring (303) by the following formula i : f i =K i (H0 i -H1 i ) Among them, K i represents the spring constant of the i-th spring (303); S6, the clamping force F of the penstock (8) to be tested is obtained by the following formula: F=K0(f1+f2+…+f n ) Wherein, n represents the total number of springs (303), and K0 represents the safety factor.

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