A pin specimen clamp for a friction testing machine

Abstract

The application discloses a pin sample clamp for a friction testing machine, which comprises a clamp cylinder assembly, an end cap and a tension ring, the clamp cylinder assembly comprises a clamp cylinder body and a rotating body arranged inside the clamp cylinder body, the rotating body is provided with a slot, the slot is provided with a rubber ring, an outer thread for connecting the end cap is arranged at one end of the clamp cylinder body, a cavity is arranged on the outer side of the clamp cylinder body close to the outer thread, an anti-vibration device is arranged in the cavity, the tension ring is arranged in the end cap, and the end cap and the anti-rotation device are matched to enable the end cap to be locked in one direction and not easy to loosen. The application solves the problem that the clamp cylinder and the end cap connected only through threads are easy to loosen under vibration, significantly enhances the anti-disturbance performance of the clamp, improves the reliability of fixing the pin sample, and effectively ensures that the friction surface is always in a horizontal state. Moreover, the pin sample can be supported and the extension length of the pin sample can be flexibly adjusted according to actual requirements, and the lifting device can keep the load from falling back.

Description

Technical Field

[0001] This invention belongs to the technical field of friction testing devices, specifically relating to a pin sample clamp for a friction testing machine. Background Technology

[0002] When studying the tribological properties of materials, pin-disc pairing is commonly used in experiments. Currently, under existing technological conditions, the clamping of pin specimens is mainly achieved through threaded fastening, specifically by manipulating a tension ring and using the tightening action of the threads to hold the pin specimen. However, during friction testing, various vibrations and frictional torques are inevitably generated, and these factors can cause the end cap to loosen. Once the end cap loosens, the tension ring loses its intended restraint, the pin specimen cannot be effectively clamped, and it may even be pressed into the fixture, preventing the friction surface from achieving the ideal horizontal state. Therefore, it is necessary to improve the existing technology and design a new type of pin specimen fixture to meet the requirements of friction testing. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a pin specimen clamp for a friction testing machine that ensures the end cap no longer loosens, supports the pin specimen, and allows for flexible adjustment of the pin specimen's extension length while maintaining the lifting device's load and preventing it from falling back.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0005] A pin sample clamp for a friction testing machine includes a clamp cylinder assembly, an end cap, and a tension ring. The clamp cylinder assembly includes a clamp cylinder body and a rotating body disposed inside the clamp cylinder body. The rotating body has a groove and a first external thread for connection. A rubber ring is installed in the groove. An internal thread corresponding to the first external thread is provided inside the clamp cylinder body. A second external thread for connecting the end cap is provided at the other end of the clamp cylinder body. A cavity is formed on the outer side of the clamp cylinder body near the second external thread, and an anti-vibration device is disposed in the cavity. The tension ring is disposed inside the end cap, and the end cap has an internal thread that mates with the second external thread. The end cap and the anti-rotation device cooperate to achieve one-way locking of the end cap, making it less prone to loosening.

[0006] Furthermore, the vibration-damping device includes a semi-threaded bolt, a torsion spring, and a ratchet assembly. The cavity has threaded holes on both sides corresponding to the semi-threaded bolt. The ratchet assembly has cantilever beams with openings at both ends. The ratchet assembly has ratchet teeth arranged in a single phase on its outer side. The torsion spring is sleeved on the outer side of the semi-threaded bolt. The semi-threaded bolt is fastened to the clamp cylinder body through the threaded hole.

[0007] Furthermore, the cantilever beam of the semi-threaded bolt, torsion spring, ratchet assembly, and threaded holes on the clamp cylinder body are coaxially mounted.

[0008] Furthermore, one end of the end cap is provided with a blind hole, and the inner side of the edge of the other end is provided with a toothed ring corresponding to the ratchet. The ratchet and the toothed ring mesh with each other to form a wedge fit, thereby realizing the single-phase locking of the end cap.

[0009] Furthermore, the radial dimension of one end of the clamp cylinder body with the second external thread is greater than the radial dimension of the other end.

[0010] Furthermore, one end of the rotating body and the semi-threaded bolt is provided with a hexagonal groove to facilitate tightening and positioning.

[0011] Furthermore, the clamp cylinder assembly also includes a tail assembly, one end of which has a shape adapted to the friction testing machine, and the other end has a third external thread. The inner side of the tail of the clamp cylinder body is provided with an internal thread that matches the third external thread, for the purpose of installing and fixing the tail assembly.

[0012] Furthermore, the length of the cavity matches the length of the pawl assembly.

[0013] Furthermore, the pawl assembly is circumferentially movable on the semi-threaded bolt by compressing a torsion spring connected to the semi-threaded bolt.

[0014] The beneficial effects of this invention are as follows:

[0015] This invention is a clamp specifically designed for pin specimens, featuring a simple structure and easy operation. Compared to pin specimen clamps that only use threaded fastening, this invention achieves unidirectional locking by engaging teeth with a unidirectionally designed ratchet, resulting in the end cap being screwed down. This significantly enhances the fixing effect on the pin specimen, improves the reliability of the fixation, and ensures that the friction surface of the pin specimen remains horizontal. Furthermore, a lifting structure with a rubber ring supports the pin specimen, preventing the rotating body from sliding down the thread due to insufficient self-locking capability. It also allows for flexible adjustment of the pin specimen's extension length, increasing the flexibility of clamping the pin specimen. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0017] Figure 2 This is a partial assembly diagram of the ratchet assembly, torsion spring, and semi-threaded bolt of the present invention;

[0018] Figure 3 This is a schematic diagram of the pawl assembly, torsion spring, and semi-threaded bolt of the present invention.

[0019] Figure 4This is a partial schematic diagram of the end cap of the present invention;

[0020] Figure 5 This is a diagram showing the positional relationship between the pawl assembly and the end cap of the present invention;

[0021] The components are: 1. End cap; 11. Blind hole; 12. Toothed ring; 2. Tensioner ring; 3. Pawl assembly; 31. Cantilever beam; 32. Racket tooth; 4. Clamping cylinder body; 41. Second external thread; 42. Cavity; 43. Threaded hole; 5. Rubber ring; 6. Rotating body; 61. First external thread; 62. Slot; 7. Tail assembly; 71. Third external thread; 8. Half-threaded bolt; 9. Torsion spring. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be described in detail below. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] like Figures 1-5 As shown, a pin sample fixture for a friction testing machine includes a fixture cylinder assembly, an end cap 1, and a tensioning ring 2. The fixture cylinder assembly includes a fixture cylinder body 4 and a rotating body 6 disposed inside the fixture cylinder body 4. The rotating body 6 is provided with a groove 62 and a first external thread 61 for connection. A rubber ring 5 is installed on the groove 62. An internal thread corresponding to the first external thread 61 is provided inside the fixture cylinder body 4. The rotating body 6 is tightly connected to the fixture cylinder body 4 through the thread. The bottom of the rotating body 6 is provided with a hexagonal groove for easy rotation. By rotating the rotating body 6, it can move up and down along the thread inside the fixture cylinder body 4. The rubber ring 5 on the rotating body 6 has a certain compression ratio, forming a stable axial constraint with the fixture cylinder body 4, preventing the rotating body 6 from sliding down along the thread due to insufficient self-locking ability when the working load is excessive during the experiment.

[0024] A second external thread 41 for connecting the end cap 1 is provided at the other end of the clamp cylinder body 4. A cavity 42 is provided on the outside of the clamp cylinder body 4 near the second external thread 41. An anti-vibration device is provided in the cavity 42. The tension ring 2 is provided in the end cap 1. The end cap 1 is provided with an internal thread that mates with the second external thread 41. The end cap 1 and the anti-rotation device work together to make the end cap 1 unidirectionally locked and not easy to loosen.

[0025] The vibration-damping device includes a semi-threaded bolt 8, a torsion spring 9, and a pawl assembly 3. The cavity 42 has threaded holes 43 on both sides corresponding to the semi-threaded bolt 8. The pawl assembly 3 has cantilever beams 31 with openings at both ends. The pawl assembly 3 has single-phase ratchet teeth 32 on its outer side. The torsion spring 9 is sleeved on the outer side of the semi-threaded bolt 8. The semi-threaded bolt 8 is fastened to the clamp cylinder body 4 through the threaded holes 43. The length of the cavity 42 matches the length of the pawl assembly 3.

[0026] During installation, the semi-threaded bolt 8, torsion spring 9, cantilever beam 31 of pawl assembly 3, and threaded hole 43 on clamp cylinder body 4 are installed coaxially. The pawl assembly 3 can move circumferentially on the semi-threaded bolt 8 by compressing the torsion spring 9 connected to the semi-threaded bolt 8.

[0027] One end of the end cap 1 is provided with a blind hole 11, and the inner side of the other end edge is provided with a toothed ring 12 corresponding to the ratchet 32. The ratchet 32 ​​and the toothed ring 12 mesh with each other to form a wedge fit. Since the design of the pawl assembly 3 is unidirectional, it only allows the end cap 1 with the toothed ring 12 to move in the direction of downward tightening, thereby achieving unidirectional locking and making the end cap 1 less prone to loosening.

[0028] The radial dimension of one end of the clamp cylinder body 4 with the second external thread 41 is greater than the radial dimension of the other end.

[0029] The rotating body 6 and the semi-threaded bolt 8 are provided with a hexagonal groove at one end for easy tightening and positioning.

[0030] The clamp cylinder assembly also includes a tail assembly 7. One end of the tail assembly 7 has a shape adapted to the friction testing machine, and the other end has a third external thread 71. The inner side of the tail of the clamp cylinder body 4 is provided with an internal thread that matches the third external thread 71, which is used to realize the installation and fixation of the tail assembly 7.

[0031] The operation and working principle of the pin specimen clamp for the friction testing machine of the present invention are as follows:

[0032] First, place the torsion spring 9 in the middle of the cantilever beams 31 at both ends of the pawl assembly 3. The through holes on the cantilever beams 31, the torsion spring 9, and the threaded holes 43 on the clamping cylinder body 4 are all installed coaxially. Rotate the semi-threaded bolt 8 so that it passes through the threaded hole 43, the through hole on the cantilever beam 31, and the torsion spring 9 from bottom to top. The semi-threaded bolt 8 forms a tight connection with the clamping cylinder body 4 through the threaded hole 43.

[0033] Then place the pin sample into the blind hole 11 of the end cap 1, and then rotate the rotating body 6 inside the clamp cylinder body 4 to move it upward. In this process, it can adjust the extension length of the pin sample and also provide axial support for the pin sample.

[0034] Then, the end cap 1 is rotated, causing it to move downwards along the thread, thereby compressing the internal tension ring 2 of the end cap 1 and clamping the pin sample. During the downward tightening process of the end cap 1, the toothed end cap 1 contacts the unidirectional ratchet 32, which compresses the torsion spring 9. This means that the ratchet 32 ​​does not constrain the downwardly tightened end cap 1 in the circumferential direction. When the end cap 1 is tightened, the ratchet 32 ​​engages with the toothed ring 12 on the end cap 1, preventing the end cap 1 from rotating upwards, thus achieving unidirectional locking. This locking structure prevents the end cap 1 from loosening, ensuring that the tension ring 2 can clamp the sample, ultimately ensuring that the friction surface of the pin sample remains horizontal.

[0035] Finally, the tail assembly 7 is threadedly connected to the clamp cylinder body 4, and the other end is connected to the testing machine.

[0036] When the friction test is completed and the pin sample needs to be removed, since the pawl assembly 3 still has a portion of its length exposed in the length direction after assembly and does not interact with the toothed ring 12 of the end cap 1, you only need to press the pawl assembly 3 downwards. Under the action of the torsion spring 9, the ratchet 32 ​​and the toothed ring 12 of the end cap 1 will disengage, and the end cap 1 can be unscrewed to remove the pin sample.

[0037] In summary, this invention solves the problem of easy loosening of the clamp cylinder and end cap with only threaded connection under vibration, significantly enhances the clamp's anti-disturbance performance, improves the reliability of the fixed pin sample, and effectively ensures that the friction surface is always in a horizontal state. Furthermore, it can support the pin sample and flexibly adjust the extension length of the pin sample according to actual needs, while ensuring that the lifting device maintains the load and does not fall back.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A pin sample holder for a friction testing machine, characterized in that, The fixture includes a clamping cylinder assembly, an end cap (1), and a tensioning ring (2). The clamping cylinder assembly includes a clamping cylinder body (4) and a rotating body (6) disposed inside the clamping cylinder body (4). The rotating body (6) is provided with a slot (62) and a first external thread (61) for connection. A rubber ring (5) is installed on the slot (62). An internal thread corresponding to the first external thread (61) is provided inside the clamping cylinder body (4). A second external thread (41) for connecting the end cap (1) is provided at the other end of the clamping cylinder body (4). A cavity (42) is opened on the outside of the clamping cylinder body (4) near the second external thread (41). An anti-vibration device is provided in the cavity (42). The tensioning ring (2) is disposed inside the end cap (1). An internal thread that mates with the second external thread (41) is provided inside the end cap (1). The end cap (1) and the anti-rotation device work together to make the end cap (1) lock in one direction and not easy to loosen. The vibration-damping device includes a semi-threaded bolt (8), a torsion spring (9), and a pawl assembly (3). The cavity (42) has threaded holes (43) on both sides corresponding to the semi-threaded bolt (8). The pawl assembly (3) has cantilever beams (31) with openings at both ends. The pawl assembly (3) has unidirectional ratchet teeth (32) on the outside. The torsion spring (9) is sleeved on the outside of the semi-threaded bolt (8). The semi-threaded bolt (8) is fastened to the clamp cylinder body (4) through the threaded hole (43). One end of the end cap (1) is provided with a blind hole (11), and the inner side of the edge of the other end is provided with a toothed ring (12) corresponding to the ratchet (32). The ratchet (32) and the toothed ring (12) mesh with each other to form a wedge fit, thereby achieving one-way locking of the end cap (1).

2. A pin sample holder for a friction testing machine according to claim 1, characterized in that, The semi-threaded bolt (8), torsion spring (9), cantilever beam (31) of pawl assembly (3) and threaded hole (43) on clamp cylinder body (4) are coaxially mounted.

3. A pin sample holder for a friction testing machine according to claim 2, characterized in that, The radial dimension of one end of the clamp cylinder body (4) having a second external thread (41) is greater than the radial dimension of the other end.

4. A pin sample holder for a friction testing machine according to claim 2, characterized in that, The rotating body (6) and the semi-threaded bolt (8) are provided with a hexagonal groove at one end for easy tightening and positioning.

5. A pin sample holder for a friction testing machine according to claim 2, characterized in that, The clamp cylinder assembly also includes a tail assembly (7), one end of which has a shape adapted to the friction testing machine, and the other end has a third external thread (71). The inner side of the tail of the clamp cylinder body (4) is provided with an internal thread that matches the third external thread (71) for the purpose of installing and fixing the tail assembly (7).

6. A pin sample holder for a friction testing machine according to claim 2, characterized in that, The length of the cavity (42) matches the length of the pawl assembly (3).

7. A pin sample holder for a friction testing machine according to claim 2, characterized in that, The pawl assembly (3) is circumferentially movable on the semi-threaded bolt (8) by compressing the torsion spring (9) connected to the semi-threaded bolt (8).

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