Pin sample clamp for friction testing machine

Abstract

The invention 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 in the clamp cylinder body, the rotating body is provided with a slot, a rubber ring is arranged on the slot, one end of the clamp cylinder body is provided with an external thread for connecting the end cap, and the other end of the clamp cylinder body is provided with an external thread for connecting the end cap. A cavity is formed in the outer side, close to the external thread, of the clamp cylinder body, an anti-vibration device is arranged in the cavity, the tensioning ring is arranged in the end cap, and the end cap is matched with the anti-vibration device so that the end cap can be locked in a one-way mode and is not prone to loosening. According to the invention, the problem that the clamp cylinder and the end cap which are only in threaded connection are easy to loosen when being vibrated is solved, the anti-disturbance performance of the clamp is obviously enhanced, the reliability of a fixed pin sample is improved, and the friction surface is powerfully ensured to be always in a horizontal state. According to actual requirements, the pin sample is supported, the extension length of the pin sample is flexibly adjusted, and meanwhile it is guaranteed that the load of the lifting device does not fall back.

Description

Technical Field

[0001] The invention belongs to the technical field of friction test devices, and in particular relates to a pin sample fixture used for a friction test machine. Background Art

[0002] When studying the tribological properties of materials, pin-disc pairing is usually used to conduct tests. At present, under existing technical conditions, the clamping of pin specimens is mainly achieved through threaded tightening. Specifically, it relies on the operation of the extrusion tension ring and the tightening effect of the thread to achieve the clamping of the pin specimen. However, in the process of friction testing, various vibrations and friction torques will inevitably be generated, and it is the existence of these factors that will cause the end cap to loosen. Once the end cap is loose, the tension ring will lose its original restraining effect, the pin specimen cannot be effectively clamped, and the pin specimen will be pressed into the fixture, making the friction surface unable to be in an ideal horizontal state. Based on this, 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] In view of the above problems, the present invention provides a pin sample fixture for a friction testing machine, which ensures that the end cap is no longer loose, and at the same time, supports the pin sample and flexibly adjusts the extension length of the pin sample, ensures that the lifting device keeps the load from falling back.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is: A pin specimen fixture for a friction testing machine comprises a fixture barrel assembly, an end cap and a tensioning ring, wherein the fixture barrel assembly comprises a fixture barrel body and a rotating body arranged inside the fixture barrel body, the rotating body is provided with a groove and a first external thread for connection, a rubber ring is installed on the groove, an internal thread corresponding to the first external thread is provided inside the fixture barrel body, a second external thread for connecting the end cap is provided at the other end of the fixture barrel body, a cavity is opened on the outer side of the fixture barrel body near the second external thread, an anti-vibration device is provided in the cavity, the tensioning ring is arranged in the end cap, an internal thread cooperating with the second external thread is provided in the end cap, and the end cap and the anti-rotation device cooperate to enable the end cap to achieve one-way locking and is not easy to loosen.

[0005] Furthermore, the anti-vibration device includes a semi-threaded bolt, a torsion spring and a pawl assembly, threaded holes corresponding to the semi-threaded bolts are arranged on both sides of the cavity, cantilever beams with openings are arranged at both ends of the pawl assembly, and a single-phase ratchet is arranged on the outside of the pawl assembly. The torsion spring is sleeved on the outside of the semi-threaded bolt, and the semi-threaded bolt is fastened to the clamp cylinder body through a threaded hole.

[0006] Furthermore, the semi-threaded bolt, the torsion spring, the cantilever beam of the pawl assembly and the threaded hole on the clamp cylinder body are installed coaxially.

[0007] Furthermore, a blind hole is provided at one end of the end cap, and a toothed ring corresponding to the ratchet is provided on the inner side of the edge of the other end, and the ratchet and the toothed ring are meshed to form a wedge-shaped fit to achieve single-phase locking of the end cap.

[0008] Furthermore, the radial dimension of one end of the clamp barrel body having the second external thread is larger than the radial dimension of the other end.

[0009] Furthermore, one end of the rotating body and the semi-threaded bolt is provided with a hexagonal groove to facilitate tightening and positioning.

[0010] Furthermore, the clamp barrel assembly also includes a tail assembly, one end of which has a shape compatible with the friction testing machine, and the other end has a third external thread. The inner side of the tail of the clamp barrel body is provided with an internal thread matching the third external thread for achieving installation and fixation of the tail assembly.

[0011] Furthermore, the length dimension of the cavity matches the length dimension of the pawl assembly.

[0012] Furthermore, the pawl assembly can move circumferentially on the semi-threaded bolt by compressing a torsion spring connected to the semi-threaded bolt.

[0013] The beneficial effects of the present invention are as follows: The present invention is a clamp specially used for pin specimens, which has a simple structure and is easy to operate. Compared with the pin specimen clamp with only threaded fastening, the present invention achieves one-way locking by screwing down the end cap through the engagement of teeth with a one-way ratchet, which greatly enhances the fixing effect of the pin specimen, improves the reliability of the fixation, and ensures that the friction surface of the pin specimen remains in a horizontal state; in addition, the lifting structure with a rubber ring is used to support the pin specimen, which can prevent the rotating body from sliding down along the thread due to insufficient self-locking ability, and flexibly adjusts the extension length of the pin specimen, which increases the flexibility of clamping the pin specimen. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the overall structure of the present invention; Figure 2 It is a partial assembly schematic diagram of the pawl assembly, the torsion spring and the semi-threaded bolt of the present invention; Figure 3 It is a schematic structural diagram of the pawl assembly, the torsion spring and the semi-threaded bolt of the present invention; Figure 4 It is a partial schematic diagram of the end cap of the present invention; Figure 5A diagram showing the position relationship between the pawl assembly and the end cap of the present invention; Among them: 1. end cap; 11. blind hole; 12. gear ring; 2. tension ring; 3. pawl assembly; 31. cantilever beam; 32. ratchet; 4. clamp 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. semi-threaded bolt; 9. torsion spring. DETAILED DESCRIPTION

[0015] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0016] like Figure 1-Figure 5 As shown, a pin sample fixture for a friction tester includes a fixture barrel assembly, an end cap 1 and a tension ring 2. The fixture barrel assembly includes a fixture barrel body 4 and a rotating body 6 arranged inside the fixture barrel 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 fixture barrel body 4. The rotating body 6 is tightly connected to the fixture barrel 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 be moved up and down along the thread in the fixture barrel body 4; the rubber ring 5 on the rotating body 6 has a certain compression rate, and forms a stable axial constraint with the fixture barrel body 4 to avoid the situation that the rotating body 6 slides down along the thread due to insufficient self-locking ability when the working load is excessive during the experiment.

[0017] A second external thread 41 for connecting the end cap 1 is provided at the other end of the clamp tube body 4, and a cavity 42 is opened on the outer side of the clamp tube body 4 near the second external thread 41, and an anti-vibration device is provided in the cavity 42. The tensioning ring 2 is arranged in the end cap 1, and an internal thread matching the second external thread 41 is arranged in the end cap 1. The end cap 1 and the anti-rotation device cooperate to enable the end cap 1 to achieve one-way locking and is not easy to loosen.

[0018] The anti-vibration device includes a semi-threaded bolt 8, a torsion spring 9 and a pawl assembly 3, threaded holes 43 corresponding to the semi-threaded bolt 8 are arranged on both sides of the cavity 42, cantilever beams 31 with openings are arranged at both ends of the pawl assembly 3, and the outer side of the pawl assembly 3 has a single-phase ratchet 32, the torsion spring 9 is sleeved on the outer side of the semi-threaded bolt 8, and the semi-threaded bolt 8 is fastened to the clamp barrel body 4 through the threaded hole 43. The length of the cavity 42 matches the length of the pawl assembly 3.

[0019] During installation, the semi-threaded bolt 8, the torsion spring 9, the cantilever beam 31 of the pawl assembly 3 and the threaded hole 43 on the clamp barrel body 4 are coaxially installed. 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.

[0020] A blind hole 11 is provided at one end of the end cap 1, and a toothed ring 12 corresponding to the ratchet 32 ​​is provided on the inner side of the edge of the other end. The ratchet 32 ​​and the toothed ring 12 are meshed with each other to form a wedge-shaped fit. Since the design of the pawl assembly 3 is unidirectional, the end cap 1 with the toothed ring 12 is only allowed to move in the downward tightening direction, thereby realizing unidirectional locking, and making the end cap 1 not easy to loosen.

[0021] The radial dimension of one end of the clamp cylinder body 4 having the second external thread 41 is larger than the radial dimension of the other end.

[0022] One end of the rotating body 6 and the semi-threaded bolt 8 is provided with a hexagonal groove to facilitate tightening and positioning.

[0023] The clamp barrel assembly also includes a tail assembly 7, one end of which has a shape compatible with the friction testing machine and the other end has a third external thread 71. The inner side of the tail of the clamp barrel body 4 is provided with an internal thread matching the third external thread 71 for installing and fixing the tail assembly 7.

[0024] The specific operation and working principle of the pin sample fixture for the friction testing machine of the present invention during operation are as follows: First, place the torsion spring 9 in the middle of the cantilever beams 31 at both ends of the pawl assembly 3. The through hole on the cantilever beam 31, the torsion spring 9 and the threaded hole 43 on the clamp tube body 4 are all coaxially installed. 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 in sequence. The semi-threaded bolt 8 forms a fastening connection with the clamp tube body 4 through the threaded hole 43.

[0025] The pin sample is then placed in the blind hole 11 of the end cap 1, and then the rotating body 6 in the clamp barrel body 4 is rotated to move it upward. In this process, the extension length of the pin sample can be adjusted, and the pin sample also has the function of axial support.

[0026] Then, the end cap 1 is rotated to move downward along the thread, thereby squeezing the internal tension ring 2 of the end cap 1, thereby clamping the pin sample. In the process of tightening the end cap 1 downward, the toothed end cap 1 contacts the one-way ratchet 32, and the ratchet 32 ​​compresses the torsion spring 9, so that the ratchet 32 ​​has no constraint on the end cap 1 tightened downward in the circumferential direction. When the end cap 1 is tightened, the ratchet 32 ​​and the toothed ring 12 on the end cap 1 engage with each other, so that the end cap 1 cannot rotate upward, thereby achieving one-way locking. This locking structure can prevent the end cap 1 from loosening, thereby ensuring that the tension ring 2 can clamp the sample, and finally ensuring that the friction surface of the pin sample is always horizontal.

[0027] Finally, the tail assembly 7 is threadedly connected to the clamp barrel body 4, and the other end is connected to the testing machine.

[0028] When the friction test is completed and the pin sample needs to be removed, since part of the length of the pawl assembly 3 is still exposed outside in the length direction when the assembly is completed and does not interact with the toothed ring 12 of the end cap 1, it is only necessary to press the pawl assembly 3 downward. Under the action of the torsion spring 9, the ratchet 32 ​​and the toothed ring 12 of the end cap 1 are disengaged, so that the end cap 1 can be unscrewed to remove the pin sample.

[0029] In summary, the present invention solves the problem that the clamp tube and the end cap connected only by threads are easy to loosen when subjected to vibration, significantly enhances the anti-disturbance performance of the clamp, improves the reliability of the fixed pin sample, and effectively ensures that the friction surface is always in a horizontal state. In addition, according to actual needs, while supporting the pin sample and flexibly adjusting the extension length of the pin sample, it can ensure that the lifting device keeps the load from falling back.

[0030] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A pin specimen fixture for a friction testing machine, characterized in that: The invention comprises a clamp barrel assembly, an end cap (1) and a tensioning ring (2), wherein the clamp barrel assembly comprises a clamp barrel body (4) and a rotating body (6) arranged inside the clamp barrel body (4), the rotating body (6) being provided with a groove (62) and a first external thread (61) for connection, a rubber ring (5) being installed on the groove (62), an internal thread corresponding to the first external thread (61) being provided inside the clamp barrel body (4), a second external thread (41) for connecting to the end cap (1) being provided at the other end of the clamp barrel body (4), a cavity (42) being provided on the outer side of the clamp barrel body (4) near the second external thread (41), an anti-vibration device being provided in the cavity (42), the tensioning ring (2) being provided in the end cap (1), an internal thread cooperating with the second external thread (41) being provided in the end cap (1), the end cap (1) and the anti-rotation device cooperating to achieve one-way locking of the end cap (1) and prevent it from loosening.

2. A pin specimen fixture for a friction testing machine according to claim 1, characterized in that: The anti-vibration device comprises a semi-threaded bolt (8), a torsion spring (9) and a pawl assembly (3); threaded holes (43) corresponding to the semi-threaded bolt (8) are arranged on both sides of the cavity (42); cantilever beams (31) with openings are arranged at both ends of the pawl assembly (3); the outer side of the pawl assembly (3) has a single-phase ratchet (32); the torsion spring (9) is sleeved on the outer side of the semi-threaded bolt (8); and the semi-threaded bolt (8) is fastened to the clamp barrel body (4) through the threaded hole (43).

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

4. A pin specimen fixture for a friction testing machine according to claim 2, characterized in that: A blind hole (11) is provided at one end of the end cap (1), and a toothed ring (12) corresponding to the ratchet teeth (32) is provided on the inner side of the edge of the other end; the ratchet teeth (32) and the toothed ring (12) are meshed to form a wedge-shaped fit, thereby achieving single-phase locking of the end cap (1).

5. A pin specimen fixture for a friction testing machine according to claim 2, characterized in that: The radial dimension of one end of the clamp barrel body (4) having the second external thread (41) is larger than the radial dimension of the other end.

6. A pin specimen fixture for a friction testing machine according to claim 2, characterized in that: One end of the rotating body (6) and the semi-threaded bolt (8) is provided with a hexagonal groove to facilitate tightening and positioning.

7. A pin specimen fixture for a friction testing machine according to claim 2, characterized in that: The clamp barrel assembly further comprises a tail assembly (7), one end of the tail assembly (7) having a shape adapted to the friction tester, and the other end having a third external thread (71), and an internal thread matching the third external thread (71) is provided on the inner side of the tail of the clamp barrel body (4) for achieving installation and fixation of the tail assembly (7).

8. A pin specimen fixture for a friction testing machine according to claim 2, characterized in that: The length dimension of the cavity (42) matches the length dimension of the pawl assembly (3).

9. A pin specimen fixture for a friction testing machine according to claim 2, characterized in that: The pawl assembly (3) can move circumferentially on the semi-threaded bolt (8), which is achieved by compressing a torsion spring (9) connected to the semi-threaded bolt (8).

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