Device for measuring thickness of oil film in piston rod

Abstract

The invention belongs to the technical field of oil film inspection and detection, and particularly discloses a device for measuring the thickness of an oil film in a piston rod, the device is located in the piston rod and comprises a measuring unit and an adjusting unit, and the measuring unit and the adjusting unit are connected through a T-shaped sleeve, the adjusting unit is used for adjusting the acoustic coupling state of the measuring unit and the inner wall of the piston rod; the measuring unit is used for measuring the oil film thickness of the inner wall of the piston rod when the measuring unit and the inner wall of the piston rod are in an acoustic coupling state. Stable contact between the ultrasonic probe and the inner wall of the piston rod can be ensured, so that the measurement precision and stability are improved.

Description

Technical Field

[0001] This application belongs to the field of oil film inspection and testing technology, specifically relating to a device for measuring the thickness of the oil film inside a piston rod. Background Technology

[0002] Reciprocating dynamic seals are widely used in structures such as hydraulic cylinders, shock absorbers, and aircraft landing gear. Their sealing performance directly affects the system's efficiency and operational safety. During reciprocating motion, a very thin lubricating oil film typically exists between the sealing lip and the mating surface. This oil film not only serves a lubricating function but is also a key factor in achieving a seal. An excessively thick oil film may lead to leakage, while an insufficiently thick film can easily cause dry friction and wear on the seal.

[0003] Currently, research on the thickness of the oil film inside reciprocating dynamic seals mainly relies on numerical simulation. A common method involves establishing a lubrication flow field model, combining different operating parameters and boundary conditions, and using software such as CFD and finite element methods to solve the governing equations, thereby predicting the spatiotemporal variation characteristics of the oil film thickness and further estimating the theoretical leakage rate. However, due to the complex dynamic contact, elastic deformation, and micro-roughness interference involved in the operating conditions of reciprocating seals, simulation models cannot fully reflect the actual operating conditions. Furthermore, uncontrollable factors such as manufacturing errors, assembly tolerances, and operating condition disturbances can also cause significant deviations between simulation results and reality.

[0004] Therefore, in-situ, real-time measurement of oil film thickness is particularly important in engineering applications. Compared to rotary seals or bearings, reciprocating seals are characterized by strong intermittent motion, limited space for installation, and high measurement accuracy, which places higher demands on the size, response speed, and stability of the measuring device. Especially in deep-hole structures, such as inside the piston rod of an aircraft landing gear, traditional measurement methods are insufficient to reliably obtain the oil film at the sealing location. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the main purpose of this application is to provide a piston rod oil film thickness measuring device. This application aims to solve the problems of poor pre-pressure adjustment, accurate positioning and poor measurement adaptability in the prior art.

[0006] To achieve the above objectives, this application provides the following technical solution: A piston rod inner oil film thickness measuring device is provided. The device is located inside the piston rod and includes a measuring unit and an adjusting unit. The measuring unit and the adjusting unit are connected by a T-shaped sleeve. The adjusting unit is used to adjust the acoustic coupling state between the measuring unit and the inner wall of the piston rod. The measuring unit is used to measure the oil film thickness of the inner wall of the piston rod when it reaches the acoustic coupling state with the inner wall of the piston rod.

[0007] Optionally, the measuring unit includes: a measuring body, which is integrally formed with the T-shaped sleeve. An ultrasonic probe and an inner hole slider are respectively provided at both ends of the measuring body. The ultrasonic probe and the inner hole slider are connected by a mechanical closed-loop structure. The mechanical closed-loop structure adjusts the acoustic coupling state between the ultrasonic probe and the inner hole slider and the inner wall of the piston rod based on the adjustment unit.

[0008] Optionally, the mechanical closed-loop structure includes: a probe pad and a rope joint bushing, wherein the probe pad is connected to the adjustment unit via a first traction member, and the rope joint bushing is connected to the adjustment unit via a second traction member.

[0009] Optionally, the probe pad has a first hole at one end facing the ultrasound probe and a first small hole at the other end facing away from the ultrasound probe. A first receiving groove is formed between the first small hole and the first hole. The first receiving groove is divided into an upper part and a lower part. The bottom end of the ultrasound probe is inserted into the upper part of the first receiving groove. The traction end of the first traction member passes through the first small hole and is located in the lower part of the first receiving groove, and is engaged with the first small hole.

[0010] Optionally, the end of the rope joint bushing facing the inner hole slider is provided with a second hole, and the end of the rope joint bushing facing away from the inner hole slider is provided with a second small hole. A second receiving groove is formed between the second hole and the second small hole. The traction end of the second traction member passes through the second small hole and is located in the second receiving groove, and is engaged with the second small hole.

[0011] Optionally, a spring is provided on the opposite side of the probe pad and the rope joint bushing, with the two ends of the spring abutting against the opposite side of the probe pad and the rope joint bushing, respectively.

[0012] Optionally, a cushioning pad is provided at the connection between the upper and lower parts of the first receiving groove.

[0013] Optionally, the inner hole slider adopts a cylindrical hollow structure.

[0014] Optionally, the contact end between the inner hole slider and the inner wall of the piston rod is provided with a ball socket, and a ball is provided in the ball socket.

[0015] Optionally, the adjustment unit includes a slotted adjustment sleeve, a sliding nut, and a washer, wherein the sliding nut and the washer are sequentially fitted onto the slotted adjustment sleeve.

[0016] Compared with existing technologies, this application can bring the following beneficial effects: Through acoustic coupling adjustment, a mechanical closed-loop structure, and flexible adjustment of springs and traction components, this device ensures stable contact between the ultrasonic probe and the inner wall of the piston rod under complex dynamic contact and spatial constraints, thereby improving measurement accuracy and stability. The overall structure of this application features high guiding accuracy, low friction, strong adaptability, and long service life, providing a reliable and accurate solution for oil film thickness measurement, particularly suitable for applications with deep hole structures and high precision requirements. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the position and structure of a piston rod oil film thickness measuring device and a piston rod according to an embodiment of this application; Figure 2 This is a schematic diagram of the overall structure of a piston rod oil film thickness measuring device according to an embodiment of this application; Figure 3 This is a schematic diagram of the internal structure of a piston rod oil film thickness measuring device according to another embodiment of this application; Figure 4 This is a partially enlarged schematic diagram of the adjustment unit provided in another embodiment of this application; Figure 5 This is a first partially enlarged schematic diagram of a measurement unit provided in another embodiment of this application; Figure 6 This is a second partially enlarged schematic diagram of a measurement unit provided in another embodiment of this application; Figure 7 This is a schematic diagram showing the combination and disassembly of the slotted adjusting sleeve and washer provided in another embodiment of this application.

[0018] The following are the descriptions of the reference numerals: 1. Ultrasonic probe; 2. Probe pad; 2-1. First hole; 2-2. First small hole; 2-3. First receiving groove; 3. Spring; 4-1. First traction component; 4-2. Second traction component; 5. Rope joint bushing; 5-1. Second hole; 5-2. Second small hole; 5-3. Second receiving groove; 6. Inner hole slider; 7. T-shaped sleeve; 8. Washer; 9. Outer nut; 10. Slotted adjusting sleeve; 11. Sliding nut; 12. Ultrasonic sensor wire; 13. Buffer pad; 14. Ball bearing. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0021] In this invention, unless otherwise explicitly specified and limited, the terms "connection," "fixed," etc., should be interpreted broadly. For example, "fixed" can mean a fixed connection, a detachable connection, or an integral part; it can mean a mechanical connection or an electrical connection; it can mean a direct connection or an indirect connection through an intermediate medium; it can mean the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0022] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0023] Figure 1 This is a schematic diagram of the position and structure of a piston rod oil film thickness measuring device and a piston rod according to an embodiment of this application; Figure 2 This is a schematic diagram of the overall structure of a piston rod oil film thickness measuring device according to one embodiment of this application. Figure 1 As shown, the measuring device is located inside the piston rod, as... Figure 2As shown, the device includes a measuring unit and an adjusting unit, which are connected by a T-shaped sleeve. The adjusting unit is used to adjust the acoustic coupling state between the measuring unit and the inner wall of the piston rod. The measuring unit is used to measure the oil film thickness on the inner wall of the piston rod when it is in an acoustic coupling state with the inner wall of the piston rod.

[0024] The measuring device provided in this embodiment utilizes the principle of acoustic coupling to accurately measure the oil film thickness while achieving good acoustic coupling with the inner wall of the piston rod. The signal is transmitted to an external measuring device via the ultrasonic sensing line 12, allowing for accurate analysis and conversion into specific data on the oil film thickness. Traditional measurement methods typically require external contact with the sealing area or rely on traditional sensors, which often struggles to maintain stability and accuracy in complex dynamic environments, especially in reciprocating motion scenarios. This device, however, precisely adjusts the acoustic coupling state between the ultrasonic probe and the inner wall of the piston rod through an adjustment unit. This addresses uncertainties caused by dynamic contact, motion friction, or changes in operating conditions, resulting in a more stable and reliable measurement process. Furthermore, the adjustment unit can adjust the pressure and position of the ultrasonic probe in real time according to actual needs, adapting to minor displacements and vibrations of the piston rod during operation. This dynamic adjustment allows the device to maintain efficient measurement even when the piston rod is constantly moving. Traditional measurement methods often lack this real-time adjustment capability, potentially limiting measurement accuracy in dynamic environments.

[0025] In another exemplary embodiment, Figure 3 This is a schematic diagram of the internal structure of a piston rod oil film thickness measuring device according to another embodiment of this application, as shown below. Figure 3 As shown, the measuring unit includes a measuring body, which is integrally formed with the T-shaped sleeve 7. An ultrasonic probe 1 and an inner hole slider 6 are respectively provided at both ends of the measuring body. The ultrasonic probe 1 and the inner hole slider 6 are connected by a mechanical closed-loop structure. The mechanical closed-loop structure adjusts the acoustic coupling state between the ultrasonic probe 1, the inner hole slider 6 and the inner wall of the piston rod based on the adjustment unit.

[0026] In this embodiment, the ultrasonic probe 1 and the inner hole slider 6 are connected by a mechanical closed-loop structure, enabling them to maintain a precise relative position during operation. Furthermore, the mechanical closed-loop structure utilizes an adjustment unit to regulate the acoustic coupling state between the ultrasonic probe 1, the inner hole slider 6, and the inner wall of the piston rod, allowing the ultrasonic probe 1 to measure oil film thickness under optimal acoustic coupling conditions with the piston rod's inner wall. This design not only improves the accuracy of oil film thickness measurement but also ensures stable and reliable measurement under dynamic environments and space-constrained conditions through precise adjustment, thus adapting to the complex working conditions of the piston rod's inner wall.

[0027] In another exemplary embodiment, such as Figure 5 and Figure 6 As shown, the mechanical closed-loop structure includes a probe pad 2 and a rope joint bushing 5. The probe pad 2 is connected to the adjustment unit through a first traction member 4-1, and the rope joint bushing 5 is connected to the adjustment unit through a second traction member 4-2.

[0028] In this embodiment, the probe pad 2 has a first hole 2-1 at the end facing the ultrasonic probe 1 and a first small hole 2-2 at the end facing away from the ultrasonic probe 1. A first receiving groove 2-3 is formed between the first small hole 2-2 and the first hole 2-1. The first receiving groove 2-3 is divided into an upper part and a lower part, wherein the diameter of the upper part is slightly larger than the diameter of the lower part. The bottom end of the ultrasonic probe 1 is inserted into the upper part of the first receiving groove 2-3. The traction end of the first traction member 4-1 passes through the first small hole 2-2 and is located at the lower part of the first receiving groove 2-3, and is engaged with the first small hole 2-2 (the traction end of the first traction member 4-1 is pressed to form an approximately spherical structure after passing through the first small hole 2-2. The diameter of the spherical end is slightly larger than the diameter of the first small hole 2-2, so that the traction end of the first traction member 4-1 can be effectively prevented from coming out of the first small hole 2-2 and separating from the probe pad 2, so as to ensure the connection stability between the first traction member 4-1 and the probe pad 2).

[0029] The end of the rope joint bushing 5 facing the inner hole slider 6 has a second hole 5-1, and the end of the rope joint bushing 5 facing away from the inner hole slider 6 has a second small hole 5-2. A second receiving groove 5-3 is formed between the second hole 5-1 and the second small hole 5-2. The second receiving groove 5-3 also includes an upper part and a lower part, and the diameter of the upper part is slightly larger than that of the lower part. The end of the inner hole slider 6 facing the rope joint bushing 5 is inserted into the upper part of the second receiving groove 5-3. The traction end of the second traction member 4-2 passes through the second small hole 5-2 and is located in the lower part of the second receiving groove 5-3, and is engaged with the second small hole 5-2 (the principle is the same as that of the first traction member 4-1 and the first small hole 2-2, which will not be described again here).

[0030] Specifically, the ultrasonic probe 1 is inserted into the first receiving groove 2-3 of the probe pad 2, where the upper diameter is slightly larger than the lower diameter to ensure stable positioning of the bottom of the ultrasonic probe 1. The traction end of the first traction member 4-1 passes through and is engaged through the first small hole 2-2, forming a near-spherical structure, which prevents the first traction member 4-1 from coming out of the first small hole 2-2, thus ensuring a firm connection between the ultrasonic probe 1 and the measurement body. The rope joint bushing 5 adopts a similar design, with the second traction member 4-2 engaged through the second small hole 5-2, ensuring a stable connection between the inner hole slider 6 and the probe pad 2.

[0031] The mechanical closed-loop structure, through precise snap-fit ​​design and mechanical closed loop, ensures high stability and high reliability of the ultrasonic probe 1 and the inner hole slider 6 during the measurement process, preventing the connecting parts from detaching in dynamic environments, and ensuring the accuracy of the measurement and the long-term stable operation of the device.

[0032] It should be noted that the first traction component 4-1 and the second traction component 4-2 can be made of a variety of traction materials with sufficient strength and elasticity, including steel wire rope, nylon rope, and synthetic fiber rope. The specific selection can be determined based on the load requirements and environmental conditions (such as humidity and corrosivity) in actual use.

[0033] In another exemplary embodiment, such as Figure 6 As shown, a spring 3 is provided on the opposite side of the probe pad 2 and the rope bushing 5, and the two ends of the spring 3 abut against the opposite side of the probe pad 2 and the rope bushing 5, respectively.

[0034] In this embodiment, a first positioning groove is provided on the contact side between the probe pad 2 and the spring 3, and the first end of the spring 3 is pressed against the first positioning groove. A second positioning groove is provided on the contact side between the rope joint bushing 5 and the spring 3, and the second end of the spring 3 is pressed against the second positioning groove.

[0035] This embodiment, by setting the first positioning groove 2-3 and the second positioning groove 5-3, ensures that both ends of the spring 3 are stably pressed against the designated positions of the probe pad 2 and the rope joint bushing 5, thereby providing precise spring positioning and a predetermined elastic force. Furthermore, the first positioning groove 2-3 and the second positioning groove 5-3 effectively prevent the spring 3 from shifting or deviating during use, ensuring that the mechanical action of the spring 3 remains consistent. This helps to avoid measurement errors caused by the displacement of the spring 3 during the measurement process.

[0036] In another exemplary embodiment, reference continues to be made to... Figure 5 A cushioning pad 13 is provided at the connection between the upper and lower parts of the first receiving groove 2-3.

[0037] In this embodiment, by providing a buffer pad 13, soft support can be provided at the connection between the upper and lower parts of the first receiving groove 2-3, which helps to reduce the direct impact force between the ultrasonic probe 1 and the probe pad 2. The buffer pad 13 can effectively absorb the impact and friction caused by factors such as mechanical vibration, dynamic contact or installation errors, thereby protecting the internal structure of the device from damage. At the same time, it can also reduce the transmission of noise and vibration, improve the stability and accuracy of the measurement process, ensure that the ultrasonic probe 1 remains stable during operation, and avoid measurement errors caused by excessive vibration or impact, thereby improving the long-term reliability and durability of the device.

[0038] In another exemplary embodiment, the inner hole slider 6 adopts a cylindrical hollow structure.

[0039] In this embodiment, the main body of the inner hole slider 6 is made of lightweight, high-strength aluminum alloy or PEEK engineering plastic and is designed as a cylindrical hollow structure. This design combines the high strength and lightweight characteristics of the materials, ensuring high-strength support and low mass of the inner hole slider 6 during operation, facilitating efficient operation in complex environments. The outer ring of the inner hole slider 6 is covered with a 30.5 mm thick self-lubricating low-friction material, such as a graphite-reinforced POM or PTFE composite layer, along the circumferential direction. These materials not only have a low coefficient of friction but also excellent wear resistance, ensuring that the piston can slide smoothly back and forth within the guide area of ​​the inner hole slider 6, which helps reduce wear and operating noise.

[0040] In addition, three discontinuous shallow annular buffer oil grooves are evenly distributed on the outer circle of the inner hole slider 6. These oil grooves can maintain a small amount of oil film during sliding, effectively relieving dry friction and small vibrations, thereby improving the smoothness of dynamic sliding, helping to reduce the accumulation of frictional heat, extend the service life of the inner hole slider, and improve the overall stability of the movement.

[0041] To accommodate slight off-center loading or axis misalignment, the inner bore of the inner slider 6 is designed as a precision-machined round hole, and can be optionally equipped with a ball socket or self-adjusting bushing structure. This structure ensures that the inner slider 6 can automatically align even when there are axial or radial deviations, thus avoiding uneven wear or jamming, and further improving the guiding accuracy and stability of the device.

[0042] In another exemplary embodiment, such as Figure 6 As shown, the contact end between the inner hole slider 6 and the inner wall of the piston rod is provided with a ball socket, and a ball bearing 14 is provided in the ball socket.

[0043] In this embodiment, the diameter of the ball socket is slightly larger than the diameter of the ball 14, and the ball socket is filled with an appropriate amount of grease to facilitate the free rolling of the ball 14. Multiple small holes are evenly punched around the circumference of the end face of the inner hole slider 6 that contacts the ball 14 to ensure that the ball will not fall out while maintaining its ability to roll freely. This design ensures that even with slight off-center loading or axial misalignment, the ball 14 can still automatically align, avoiding uneven wear and jamming caused by misalignment.

[0044] The above structure can effectively improve the guiding accuracy of the measuring device and reduce frictional resistance, so that the inner hole slider can work stably and smoothly even under complex working conditions, thereby greatly enhancing the reliability of the measuring device. In another exemplary embodiment, such as Figure 4 and Figure 7 As shown, the adjustment unit includes a slotted adjustment sleeve 10, a sliding nut 11, and a washer 8, wherein the sliding nut 11 and the washer 8 are sequentially sleeved on the slotted adjustment sleeve 10.

[0045] In this embodiment, the slotted adjusting sleeve 10 and the sliding nut 11 can adjust the ultrasonic probe 1 and the inner hole slider 6 through a precise mechanical structure. Specifically, one end of the slotted adjusting sleeve 10 is provided with a first opening slot and a second opening slot. These opening slots cooperate with the connecting ribs between the inner and outer rings of the sliding nut 11 to ensure a stable connection between the two. The other end of the slotted adjusting sleeve 10 is cylindrical with a square cutout to adapt to the overall structure of the device. The first traction member 4-1 and the second traction member 4-2 are combined into one strand inside the T-shaped sleeve 7, and then pass through the small hole located in the center of the sliding nut 11. By adjusting the length and pressing it into a near-spherical shape slightly larger than the small hole, the two traction members are prevented from disengaging from the sliding nut 11, thereby ensuring the stability of the connection between the traction members and the sliding nut 11.

[0046] Furthermore, the outer ring of the sliding nut 11 is provided with an external thread that mates with the internal thread of the T-shaped sleeve 7, allowing the slotted adjusting sleeve 10 to pass through the open hole of the outer nut after it is engaged with the sliding nut 11, ensuring precise alignment of the device during installation. The open hole and the stepped shaft of the slotted adjusting sleeve 10 are fitted with a small clearance of H8 / f8, and the outer nut is tightened and fixed on the T-shaped sleeve to complete the assembly of the device.

[0047] During use, the maximum pre-pressure of the ultrasonic probe and the inner hole slider on the inner wall of the piston rod is first adjusted by grinding the washers or adjusting the length of the steel wire rope. Then, by rotating the slotted adjusting sleeve, the sliding nut is moved axially, pulling the traction component to make the probe pad and the rope section bushing move towards each other, thereby applying pressure to the inner wall of the piston rod by the ultrasonic probe and the inner hole slider. The outer diameter of the device is adjusted to ensure that the device can move freely within the piston rod hole.

[0048] When the measuring device reaches the designated position (e.g., the sealing area), by continuing to rotate the slotted adjusting sleeve, the sliding nut moves to the right. The traction component, probe pad, and rope bushing move upwards or downwards under the action of the helical spring until they contact the ultrasonic probe and the inner hole slider. At this point, by slowly rotating the slotted adjusting sleeve, the tension of the traction component is reduced, adjusting the pressure applied to the inner wall of the piston rod by the ultrasonic probe and the inner hole slider. This pressure is the spring force of the helical spring minus the tension of the wire rope, ensuring accurate and stable pressure during the measurement process.

[0049] This fine adjustment mechanism enables the device to adapt flexibly to complex working environments, ensures the accuracy of ultrasonic measurements, continuously and stably measures oil film thickness, and adapts to different sealing locations and working conditions.

[0050] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A device for measuring the thickness of an oil film inside a piston rod, characterized in that, The device is located inside the piston rod, and the device includes: A measuring unit and an adjusting unit are connected by a T-sleeve. in, The adjustment unit is used to adjust the acoustic coupling state between the measuring unit and the inner wall of the piston rod; The measuring unit is used to measure the oil film thickness on the inner wall of the piston rod when it is acoustically coupled with the inner wall of the piston rod.

2. The apparatus according to claim 1, characterized in that, The measurement unit includes: The measuring body is integrally formed with the T-shaped sleeve. An ultrasonic probe and an inner hole slider are respectively installed at both ends of the measuring body. The ultrasonic probe and the inner hole slider are connected by a mechanical closed-loop structure. The mechanical closed-loop structure adjusts the acoustic coupling state of the ultrasonic probe and the inner hole slider with the inner wall of the piston rod based on the adjustment unit.

3. The apparatus according to claim 2, characterized in that, The mechanical closed-loop structure includes: Probe pad and rope joint bushing, in, The probe pad is connected to the adjustment unit via the first traction component. The rope joint bushing is connected to the adjustment unit via a second traction member.

4. The apparatus according to claim 3, characterized in that, The probe pad has a first hole at one end facing the ultrasound probe and a first small hole at the other end facing away from the ultrasound probe. A first receiving groove is formed between the first small hole and the first hole. The first receiving groove is divided into an upper part and a lower part. The bottom end of the ultrasound probe is inserted into the upper part of the first receiving groove. The traction end of the first traction member passes through the first small hole and is located in the lower part of the first receiving groove, and is engaged with the first small hole.

5. The apparatus according to claim 3, characterized in that, The end of the rope joint bushing facing the inner hole slider is provided with a second hole, and the end of the rope joint bushing facing away from the inner hole slider is provided with a second small hole. A second receiving groove is formed between the second hole and the second small hole. The traction end of the second traction member passes through the second small hole and is located in the second receiving groove, and is engaged with the second small hole.

6. The apparatus according to claim 3, characterized in that, A spring is provided on the opposite side of the probe pad and the rope joint bushing, with the two ends of the spring abutting against the opposite side of the probe pad and the rope joint bushing, respectively.

7. The apparatus according to claim 4, characterized in that, A cushioning pad is provided at the connection between the upper and lower parts of the first receiving groove.

8. The apparatus according to claim 2, characterized in that, The inner hole slider adopts a cylindrical hollow structure.

9. The apparatus according to claim 2, characterized in that, The contact end between the inner hole slider and the inner wall of the piston rod is provided with a ball socket, and a ball is provided in the ball socket.

10. The apparatus according to claim 1, characterized in that, The adjustment unit includes a slotted adjustment sleeve, a sliding nut, and a washer, wherein the sliding nut and the washer are sequentially fitted onto the slotted adjustment sleeve.

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