A method and device for evaluating the surface adaptability of a hydraulic cylinder piston rod-seal

Abstract

The present invention discloses a method and device for evaluating the surface adaptability of a hydraulic cylinder piston rod and seal, belonging to the technical field of hydraulic cylinders. The method comprises the following steps: driving the seal to reciprocate on the piston rod; applying a radial load to the piston rod; collecting and recording the friction between the piston rod and the seal in real time during the reciprocating motion; detecting the amount of hydraulic oil leakage in the hydraulic cylinder during the test; calculating the weight reduction due to seal wear; and evaluating the surface adaptability of the piston rod and seal by considering the friction between the piston rod and the seal, the amount of hydraulic oil leakage, and the weight reduction of the seal. The present invention proposes a multi-dimensional evaluation of the adaptability of the friction between the piston rod and the seal, the amount of hydraulic oil leakage, and the amount of seal wear, and designs detection methods with different evaluation indicators. This method can more comprehensively and systematically evaluate the matching of the piston rod surface coating and state with the seal coating and surface quality state.

Description

Technical Field

[0001] The invention relates to a method and a device for evaluating the surface adaptability of a hydraulic cylinder piston rod and a sealing element, and belongs to the technical field of hydraulic cylinders. Background Art

[0002] As a key hydraulic actuator, hydraulic cylinders convert hydraulic energy into mechanical energy and can withstand extremely high loads. They are widely used in large-scale equipment such as engineering machinery, offshore equipment, and water conservancy machinery. Piston hydraulic cylinders are a common type of hydraulic cylinder. They rely primarily on seals between the piston and the inner wall of the cylinder barrel, and between the guide sleeve and the piston rod to achieve internal high pressure, thereby driving the working device to overcome high loads.

[0003] During service, the operating environment of hydraulic cylinders is usually harsh, rich in corrosive media, dust and impact of external hard particles. Therefore, the surface of the hydraulic cylinder piston rod is required to have properties such as wear resistance, corrosion resistance, and collision resistance. In response to the above problems, the industry widely uses surface treatment technologies to strengthen the surface of the piston rod, including supersonic flame spraying technology, plasma spraying technology, ultra-high-speed laser cladding technology, etc. At the same time, seals in harsh environments are prone to failure due to wear, hydrolysis, aging, etc., and seals in extreme environments should also have special properties such as high temperature resistance and high load-bearing capacity. Therefore, in order to meet the use requirements under different working conditions, there are many existing seal structures and material types, and the industry also uses vacuum coating and other process technologies to strengthen the surface of seals. However, coatings prepared by different surface treatment technologies have different surface morphologies. For example, WC coatings prepared by supersonic flame spraying technology have high hardness, porosity ≤1%, and surface roughness after processing can reach Ra0.1μm or less. Another example is the Cr2O3-TiO2 coating prepared by plasma spraying technology, which has a porosity of approximately 3%-4%, a surface roughness ≥0.3 microns after processing, and small pits are evenly distributed on the surface. Traditional electroplating layers and ultra-high-speed laser cladding layers are dense inside, with a porosity generally ≤0.1%, and no defects such as pits are produced on their surfaces after processing. At the same time, the surface morphology and performance of seals are directly related to their structural form, material type, and surface treatment process.

[0004] Therefore, in order to meet the performance requirements of hydraulic cylinders in different service environments, it is of great significance to solve the design problem of matching the piston rod surface coating and state with the seal coating and surface quality state. To this end, the present invention proposes a hydraulic cylinder piston rod-seal surface compatibility evaluation method and device. Summary of the Invention

[0005] The purpose of the present invention is to overcome the technical problem in the prior art that the piston rod surface coating and state are difficult to match with the seal coating and surface quality state, and to provide a hydraulic cylinder piston rod-seal surface adaptability evaluation method and device, which can realize accurate testing under the combined action of multiple factors such as piston rod material and surface quality, seal material and surface quality, load form, and movement speed, providing technical support for the development of high-performance hydraulic cylinders in harsh environments.

[0006] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions:

[0007] In a first aspect, the present invention provides a method for evaluating the surface adaptability of a hydraulic cylinder piston rod and a seal, comprising the following steps:

[0008] The driving seal reciprocates on the piston rod;

[0009] applying a radial load on the piston rod;

[0010] Collect and record the friction between the piston rod and the seal in real time during reciprocating motion;

[0011] Detect the leakage of hydraulic oil in the hydraulic cylinder during the test;

[0012] Calculate the weight reduction due to seal wear;

[0013] The piston rod-seal surface adaptability was evaluated by considering the friction between the piston rod and the seal, the hydraulic oil leakage, and the weight reduction of the seal.

[0014] Based on the first aspect, further, during the reciprocating motion of the drive seal on the piston rod, the speed of the reciprocating motion is changed.

[0015] Based on the first aspect, further, when a radial load is applied to the piston rod, radial loads of different sizes and directions are applied to the piston rod.

[0016] Based on the first aspect, further, detecting the hydraulic oil leakage includes weighing the seal before and after the test, and comparing the weight loss of the seal after wear.

[0017] Based on the first aspect, further, a surface morphology analyzer is used to analyze the wear morphology of the seal, and then analyze the wear degree of the seal.

[0018] In the second aspect, the present invention also provides a hydraulic cylinder piston rod-seal surface adaptability evaluation device, which is applied to the evaluation method described in any scheme of the first aspect, including a test bench and a cylinder barrel slidably arranged on the test bench, a piston rod passing through the cylinder barrel, and a force sensor connected to one end of the piston rod. The evaluation device also includes a reciprocating drive mechanism for driving the cylinder barrel to reciprocate on the piston rod and a radial load mechanism for applying a radial load on the piston rod.

[0019] On the second aspect, further, the reciprocating drive mechanism includes a driving motor built into the test bench and a crank rocker mechanism connected to the motor output shaft, a slide rail is provided on the test bench, and the bottom of the cylinder is connected to a base slidably connected to the slide rail, and the crank rocker mechanism is hinged with a shift rod at one end away from the output shaft of the driving motor, and the shift rod is connected to the base, and drives the cylinder to reciprocate when the driving motor drives the crank rocker mechanism.

[0020] Furthermore, the radial load mechanism includes an eccentric motor installed in the test bench, the output shaft of the eccentric motor is fixedly connected to a connecting rod, and the connecting rod is penetrated by a through hole adapted to pass through the end of the piston rod away from the force sensor, so that when the eccentric motor is started, it drives the connecting rod to apply a radial load to the piston rod.

[0021] Furthermore, the cylinder is provided with an oil inlet and an oil outlet, and the guide sleeve in the cylinder is provided with a leakage oil collection channel.

[0022] Furthermore, the piston rod is connected to two limit blocks, and the opposite sides of the two limit blocks are used to contact the connecting rod and the force sensor respectively when the piston rod moves axially.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] The present invention discloses a method and device for evaluating the surface adaptability of a hydraulic cylinder piston rod and a seal. The method proposes a multi-dimensional evaluation of the adaptability of the friction between the piston rod and the seal, the amount of hydraulic oil leakage, and the amount of seal wear. A surface topography analyzer is used to analyze the seal wear topography and, in turn, the degree of seal wear. Detection methods with different evaluation indicators are designed to more comprehensively and systematically evaluate the matching of the piston rod surface coating and state with the seal coating and surface quality state.

[0025] The adaptability evaluation method and device provided by the present invention can realize the application of continuously dynamically changing test loads as well as the application of test loads with a fixed direction and constant magnitude, thereby satisfying the matching evaluation of the surface coating and state of the hydraulic cylinder piston rod and the coating and surface quality state of the seal under different working conditions. It can accurately test the combined effects of multiple factors such as the piston rod material and surface quality, the seal material and surface quality, the load form, and the movement speed, providing technical support for the development of high-performance hydraulic cylinders in harsh environments.

[0026] The present invention realizes the reciprocating motion of the cylinder through a crank rocker mechanism in conjunction with a drive motor, and simultaneously tests and evaluates the influence of different motion speeds on the adaptability between the piston rod and the seal in one test, thereby significantly improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a flowchart of the steps of the method for evaluating the surface adaptability of a hydraulic cylinder piston rod and a seal in the first embodiment of the present invention;

[0028] Figure 2 Schematic diagram of the structure of the hydraulic cylinder piston rod-seal surface adaptability evaluation device in the second embodiment of the present invention;

[0029] Figure 3 Schematic diagram of the structure of the reciprocating drive mechanism in the second embodiment of the present invention;

[0030] Figure 4 Schematic diagram of the principle of applying radial load in the first embodiment of the present invention;

[0031] Figure 5 is a structural cross-sectional view of the cylinder in the second embodiment of the present invention;

[0032] Figure 6 This is a graph showing the variation of friction force over test time when an embodiment of the present invention is applied to the evaluation of a piston rod-seal of an all-terrain crane suspension cylinder;

[0033] Figure 7 This is a graph showing how friction changes with test time when an embodiment of the present invention is applied to the evaluation of a piston rod-seal component of an outrigger oil cylinder of an automobile crane.

[0034] In the figure: 1. test bench; 2. slide rail; 3. base; 4. cylinder; 41. guide sleeve; 5. piston rod; 6. crank rocker mechanism; 7. shift rod; 8. force sensor; 9. eccentric motor; 10. connecting rod; 11. limit block. DETAILED DESCRIPTION

[0035] In the description of the present invention, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0036] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; mechanical connections or electrical connections; direct connections or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0037] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0038] Example 1

[0039] Factors affecting the adaptability of the hydraulic cylinder piston rod and seals include: piston rod coating type and processing status, seal material and surface status, movement speed, test load, etc. This embodiment adopts specific surface treatment technology and materials to prepare corresponding coatings on the piston rod surface according to the actual hydraulic cylinder piston rod and seal design scheme, and adopts corresponding materials and processes to prepare corresponding seals. According to the hydraulic cylinder design scheme, the sealing structure and combination of the guide sleeves on both sides of the test cylinder can be designed as different sealing combinations and sealing materials. By changing the piston rod surface coating type, forming process type, finishing surface quality, as well as seal material, surface treatment process and sealing combination form and other factors, the adaptability evaluation between different piston rods and seals can be achieved. For example Figure 1 As shown, this embodiment provides a method for evaluating the surface adaptability of a hydraulic cylinder piston rod and a seal, which specifically includes the following steps:

[0040] The driving seal moves back and forth on the piston rod. During the process of driving the seal to move back and forth on the piston rod, the speed of the reciprocating motion is changed. The speed of motion is a key evaluation index of the working performance of the hydraulic cylinder. The speed will affect the formation of the oil film between the piston rod and the sealing surface, and thus affect the adaptability between the two. In order to improve the test efficiency, the present invention adopts a feeding method in which the piston rod is relatively fixed and the cylinder barrel reciprocates, and the test speed is controlled by adjusting the reciprocating speed of the cylinder barrel. Figure 3 As shown, the present invention designs a cylinder reciprocating motion drive mode of crank rocker + horizontal linear guide. By adjusting the number of motor revolutions, the reciprocating motion speed can be adjusted during a cyclic feeding process. At the same time, by changing the length of the crank and rocker, the reciprocating stroke can be regulated, and then the influence of different speeds on the adaptability between the piston rod and the seal can be evaluated, which significantly improves the test efficiency.

[0041] like Figure 4 As shown, in this embodiment, a radial load is applied to the piston rod. When the radial load is applied to the piston rod, radial loads of different sizes and directions are applied to the piston rod. An eccentric motor is used as the driving system. During the rotation of the motor, the axis of the output shaft performs a circular motion around the rotation center line of the motor. The eccentric effect of the output shaft is utilized to apply a radial load to the piston rod under test through the connecting rod. According to the experimental test plan, by driving the motor to rotate continuously, a radial load that continuously and dynamically changes in all directions can be applied to the piston rod under test. At the same time, the eccentric motor can accurately control the rotation angle. Different rotation angles can apply radial loads of different sizes and directions to the piston rod under test, thereby meeting different lateral test load control requirements;

[0042] In this embodiment, the friction force between the piston rod and the seal during the reciprocating motion is collected and recorded in real time, and the variation pattern of the friction force with test time, reciprocating motion speed, test load and other factors is established to analyze the influence of various influencing factors on the surface adaptability of the piston rod and the seal.

[0043] This embodiment also analyzes the compatibility between the hydraulic cylinder piston rod and the seal by detecting the amount of hydraulic oil leakage in the hydraulic cylinder during the test. Specifically, the seal is weighed before and after the test, and the weight loss of the seal after wear is compared. The weight loss of the seal due to wear is calculated, and the wear morphology of the seal is analyzed using a surface morphology analyzer to analyze the wear degree of the seal under specific test parameters.

[0044] This embodiment comprehensively considers the friction between the piston rod and the seal, the amount of hydraulic oil leakage and the weight reduction of the seal to evaluate the piston rod-seal surface adaptability, and realizes the matching test of the piston rod surface coating and state with the seal coating and surface quality state.

[0045] Example 2

[0046] like Figure 2As shown, this embodiment discloses a hydraulic cylinder piston rod-seal surface adaptability evaluation device, which is applicable to the evaluation method in Example 1. The device includes a test bench and a cylinder barrel slidably arranged on the test bench, a piston rod passing through the cylinder barrel, and a force sensor is connected to one end of the piston rod. The device also includes a reciprocating drive mechanism for driving the cylinder barrel to reciprocate on the piston rod and a radial load mechanism for applying a radial load on the piston rod.

[0047] The reciprocating drive mechanism in this embodiment includes a drive motor built into the test bench and a crank rocker mechanism connected to the motor output shaft. A slide rail is provided on the test bench, and a base slidably connected to the slide rail is connected to the bottom of the cylinder. A shift rod is hinged at one end of the crank rocker mechanism away from the output shaft of the drive motor, and the shift rod is connected to the base. When the drive motor drives the crank rocker mechanism, it drives the cylinder to reciprocate. The cylinder can reciprocate along the axis of the piston rod, and the freedom of movement in other directions is restricted. Driven by the crank rocker mechanism, the movement speed of the tested cylinder is constantly changing within a reciprocating motion cycle, that is, the relative movement speed between the piston rod and the seal is changing. Therefore, one test can test and evaluate the influence of different movement speeds on the adaptability between the piston rod and the seal, thereby significantly improving the test efficiency.

[0048] The radial load mechanism in this embodiment includes an eccentric motor installed in the test bench. The output shaft of the eccentric motor is fixedly connected to a connecting rod. The connecting rod is penetrated by a through hole that is adapted to penetrate the end of the piston rod away from the force sensor. When the eccentric motor is started, it drives the connecting rod to apply a radial load to the piston rod. Since it is relatively fixed to the surface of the test bench, the eccentric action of the eccentric motor drives the lower end of the connecting rod to deviate around the central axis. When the motor rotates continuously, it generates dynamic loads that change periodically along different radial directions on the piston rod under test. At the same time, since the loads applied to the piston rod at different rotation angles are different, different and constant test loads can be applied to the piston rod by precisely controlling the rotation angle of the eccentric motor. In order not to affect the test accuracy of the friction between the piston rod and the seal during the test, a ball connection is used between the connecting rod and the contact surface of the piston rod in this embodiment.

[0049] like Figure 5 As shown, the cylinder is provided with an oil inlet and an oil outlet. During the test, the internal pressure of the cylinder can be kept consistent with the actual working pressure of the hydraulic cylinder, so that the interaction between the seal and the piston rod during the test is consistent with the actual working process, which is beneficial to improving the accuracy of the test results. Guide sleeves and glands are installed on both sides of the cylinder. The surface treatment process and materials of the piston rod, the guide sleeve seal combination form, the sealing material, etc. can be designed with reference to the actual hydraulic cylinder, and the guide sleeve in the cylinder is provided with a leakage oil collection channel to detect the sealing performance of the hydraulic cylinder during the test.

[0050] like Figure 2As shown, there are two limit blocks on both ends of the piston rod connected by threads, and the back sides of the two limit blocks are used to contact the connecting rod and the force sensor when the piston rod moves axially, which can limit the axial stroke length of the piston rod itself. A data acquisition and control system and a display are also provided on the test bench to control the drive motor and the eccentric motor and collect and display the collected information of the force sensor. The force sensor adopts a tensile and compressive sensor, which can detect the friction value between the piston rod and the seal during the reciprocating motion, and record the change of friction force over time in real time through the data acquisition system. The control system can set the rotation speed of the eccentric motor and the drive motor, thereby realizing the regulation of the test load and reciprocating motion speed.

[0051] The following are specific application examples of the embodiments of the present invention.

[0052] (1) Evaluation of the surface adaptability of the piston rod-seal of the all-terrain crane suspension cylinder

[0053] The suspension cylinder of a large-tonnage truck crane connects the axle to the chassis. During driving, the hydraulic cylinder must withstand significant lateral loads, and road bumps can cause the relative velocity between the piston rod and the seal to vary. To simulate the surface conditions of an actual suspension cylinder piston rod, a WC-Co coating was applied using a supersonic flame spraying process. The test rod had a diameter of 100 mm and a length of 700 mm, with a coating thickness of 0.3 mm. After application, the surface was ground and polished to an Ra of 0.2 μm using a diamond abrasive belt. The sealing system consisted of a step seal, a self-lubricating polyurethane shaft seal, a phenolic resin support ring, and a self-lubricating polyurethane dust seal. During testing, the eccentric motor was set at a rotational speed of 6 rpm. Due to the eccentricity of the motor output shaft, a radially distributed, periodically varying load was applied between the test piston rod and the seal via the connecting rod, with a loading frequency of 0.1 Hz. Simultaneously, the crankshaft drive motor rotated at the same speed as the eccentric motor, resulting in a reciprocating cycle of the cylinder relative to the test piston rod taking 10 s. The initial position of the eccentric motor output shaft is as follows Figure 4 On the left side of the horizontal position shown, the crank is initially in a horizontal state. After the test begins, the eccentric motor and the drive motor both rotate clockwise around the center of rotation. Figure 6The figure shows the friction curve collected during the experiment. During the test time of 0-5s, the lateral load applied by the connecting rod to the piston rod first increases and then decreases. At the same time, the movement speed of the cylinder relative to the piston rod first increases and then decreases. The measured friction force shows a change pattern of first increasing and then decreasing. During the test time of 5-10s, the test load and the movement speed change in opposite directions, and the direction of the measured friction force also changes. As the number of reciprocating motions increases, an oil film gradually forms between the piston rod and the seal, and the friction value shows a trend of gradually decreasing. After the test, the hydraulic oil leakage and the surface wear of the seal during the process were analyzed to determine the adaptability between the piston rod and the seal. Furthermore, by replacing different piston rod coatings and seal combinations, it is possible to finally analyze the piston rod coating and seal combination with the best adaptability under this working condition.

[0054] (2) Evaluation of the surface adaptability of the "piston rod-seal" component of the outrigger cylinder of a truck crane

[0055] The outrigger cylinder of a truck crane is primarily used to withstand the rollover forces generated during heavy lifting. Consequently, significant lateral forces are generated between the piston rod and the seal, causing changes in the extension length of the outrigger cylinder piston rod. This means that relative movement occurs between the piston rod and the seal during the lateral force, thus requiring high adaptability between the piston rod and the seal. The method and apparatus developed in this paper were used to test and analyze the adaptability between the piston rod and the seal. The piston rod was treated with hard chrome electroplating and polished to Ra 0.2μm. The diameter was 100mm and the length was 300mm. The sealing system employed a combination of a polyoxymethylene support ring, an F4 bronze support ring, an oil-free bearing, a polytetrafluoroethylene (PTFE) O-ring, and a polytetrafluoroethylene (PTFE) shaft seal. The lateral forces experienced by the outrigger cylinder during lifting can be equated to a side load of fixed direction and constant magnitude, with minimal relative sliding displacement and velocity. Therefore, by precisely adjusting the rotation angle of the eccentric motor, a fixed, constant side load could be applied between the piston rod and the seal under test. At the same time, changing the length L of the crank in the crank rocker mechanism can achieve the adjustment of the cylinder reciprocating stroke B, where B=2*L. During the test, the reciprocating speed of the cylinder can be adjusted by setting the speed of the drive motor. Figure 7 The graph shows the friction between the piston rod and seal during the test. It shows that friction is relatively high at low speeds, but decreases as speed increases. The compatibility between the piston rod and seal was also comprehensively analyzed, taking into account hydraulic oil leakage and seal wear during the test.

[0056] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for evaluating the surface adaptability of a hydraulic cylinder piston rod and a seal, characterized in that: The following steps are involved: The driving seal reciprocates on the piston rod; applying a radial load on the piston rod using a radial load mechanism; A force sensor (8) connected to one end of the piston rod (5) is used to collect and record the friction force between the piston rod and the seal in real time during the reciprocating motion; Detect the leakage of hydraulic oil in the hydraulic cylinder during the test; Calculate the weight reduction due to seal wear; The piston rod-seal surface compatibility is evaluated by considering the friction between the piston rod and the seal, the amount of hydraulic oil leakage, and the weight reduction of the seal; The radial load mechanism includes an eccentric motor (9) installed in the test bench (1), the output shaft of the eccentric motor (9) is fixedly connected to a connecting rod (10), and the connecting rod (10) is penetrated by a through hole adapted to penetrate the end of the piston rod (5) away from the force sensor (8), so that when the eccentric motor (9) is started, it drives the connecting rod (10) to apply a radial load to the piston rod (5).

2. The surface adaptability evaluation method according to claim 1, characterized in that: During the reciprocating motion of the driving seal on the piston rod, the speed of the reciprocating motion is changed.

3. The surface adaptability evaluation method according to claim 1, characterized in that: When a radial load is applied to the piston rod, radial loads of different magnitudes and directions are applied to the piston rod.

4. The surface adaptability evaluation method according to claim 1, characterized in that: Detecting the hydraulic oil leakage includes weighing the seal before and after the test, and comparing the weight loss of the seal after wear.

5. The surface adaptability evaluation method according to claim 4, characterized in that: A surface morphology analyzer is used to analyze the wear morphology of the seal and then analyze the wear degree of the seal.

6. A hydraulic cylinder piston rod-seal surface adaptability evaluation device, applied to the evaluation method according to any one of claims 1 to 5, characterized in that: The evaluation device comprises a test bench (1) and a cylinder (4) slidably arranged on the test bench (1), wherein a piston rod (5) is passed through the cylinder (4), and one end of the piston rod (5) is connected to a force sensor (8), and the evaluation device further comprises a reciprocating drive mechanism for driving the cylinder (4) to reciprocate on the piston rod and a radial load mechanism for applying a radial load on the piston rod (5); The radial load mechanism includes an eccentric motor (9) installed in the test bench (1), the output shaft of the eccentric motor (9) is fixedly connected to a connecting rod (10), and the connecting rod (10) is penetrated by a through hole adapted to penetrate the end of the piston rod (5) away from the force sensor (8), so that when the eccentric motor (9) is started, the connecting rod (10) is driven to apply a radial load to the piston rod (5).

7. The surface adaptability evaluation device according to claim 6, characterized in that: The reciprocating drive mechanism includes a drive motor built into the test bench (1) and a crank rocker mechanism (6) connected to the motor output shaft, a slide rail (2) is provided on the test bench (1), and the bottom of the cylinder barrel (4) is connected to a base (3) slidably connected to the slide rail (2), and the crank rocker mechanism (6) is hinged to an end away from the drive motor output shaft with a shift lever (7), and the shift lever (7) is connected to the base (3), and drives the cylinder barrel (4) to reciprocate when the drive motor drives the crank rocker mechanism (6).

8. The surface adaptability evaluation device according to claim 6, characterized in that: The cylinder barrel (4) is provided with an oil inlet and an oil outlet, and the guide sleeve (41) inside the cylinder barrel (4) is provided with a leaked oil collection channel.

9. The surface adaptability evaluation device according to claim 6, characterized in that: Two limit blocks (11) are connected to the piston rod (5), and the opposite sides of the two limit blocks (11) are used to contact the connecting rod (10) and the force sensor (8) respectively when the piston rod (5) moves axially.

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