Plunger pair gap sealing design, sealing test method and test system thereof

Abstract

The invention belongs to the technical field of high-pressure sealing, and particularly relates to a plunger pair gap sealing design, a sealing testing method and a testing system thereof. The plunger sleeve comprises a first shaft section, a second shaft section, a third shaft section and a fourth shaft section; an inner hole of the plunger sleeve is an equal-diameter cylindrical surface; the plunger comprises a top shaft section and a tail shaft section which are the same in radius, and a reducing shaft section located between the top shaft section and the tail shaft section. By changing the structural design of the plunger and the plunger sleeve, the outer diameter of the plunger can be adaptively expanded under the action of high pressure, the deformation of the inner diameter of the plunger sleeve is counteracted in real time, the fit clearance between the plunger and the plunger sleeve is kept stable, and the high-pressure sealing problem is fundamentally solved. A miniature probe is installed on a plunger sleeve low-pressure liquid pipe, and the sealing performance of the plunger pair is tested by testing the liquid flowing direction of the low-pressure liquid pipe.

Description

Technical Field

[0001] The present application belongs to the field of high-pressure sealing technology, and in particular relates to a plunger pair gap sealing design, a sealing test method and a test system thereof. Background Art

[0002] The sealing performance of equipment such as plunger pairs, high-pressure pumps using the reciprocating motion of plungers as pressure-boosting elements, high-pressure, high-flow hydraulic components, hydraulic systems, high-frequency electro-hydraulic servo valves, proportional valves, and high-performance hydraulic system sealing devices is a key technical indicator, directly affecting the equipment's leakage control, operating efficiency, maintenance costs, and service life. Under ultra-high pressure conditions, the plunger sleeve undergoes elastic deformation due to the huge radial hydraulic pressure, resulting in an increase in the fit clearance between the plunger and the plunger sleeve, a decrease in sealing performance, and the following problems: increased leakage, supply pressure fluctuations, and shortened component life. In the existing technology, to improve sealing performance, solutions such as strengthening the rigidity of the plunger sleeve, optimizing the initial fit clearance, and introducing complex compensation structures are usually adopted. However, strengthening the rigidity of the plunger sleeve will increase the size and weight of the hydraulic equipment and significantly increase processing costs. Optimizing the initial fit clearance will cause the plunger sleeve to deform under high pressure, resulting in a dynamic expansion of the gap, which cannot fundamentally solve the sealing problem. Introducing a complex compensation structure can only partially offset the deformation, and the structure is complex, with high reliability risks, making it difficult to achieve large-scale application. Summary of the Invention

[0003] The purpose of the present invention is to address the problems of high cost, structural redundancy, or insufficient adaptability of existing high-pressure sealing solutions. It provides a new sealing design that can dynamically adapt to high-pressure working conditions and actively compensate for plunger sleeve deformation. While ensuring the compactness and reliability of the equipment, it improves sealing performance and reduces leakage, thereby meeting the requirements of high efficiency and long life of the equipment. A plunger pair clearance seal design, seal testing method, and corresponding testing system are also provided.

[0004] To achieve the above objectives, the present invention adopts the following technical solutions.

[0005] A plunger pair clearance seal design method includes the following steps:

[0006] Step 1: plunger sleeve design;

[0007] The plunger sleeve includes a length The first shaft segment, length The second shaft segment, length The third axis segment, length The fourth shaft section; the inner hole of the plunger sleeve is a cylindrical surface with equal diameter;

[0008] in is a constant ranging from 1.5 to 2.0; Hy is the distance from the top dead center of the plunger to the upper edge of the plunger sleeve; 1.1~1.3; S is the stroke of the plunger; 1.0~1.2; D is the inner diameter of the plunger sleeve; L is the total length of the plunger sleeve;

[0009] The thickness of each axial section of the plunger sleeve is: ;

[0010] Wherein is the thickness of the m-th axial section, m is 1, 2, 3, or 4; is a constant, and the value range is 0.7~1.1; P is the maximum pressure of the plunger pressure chamber, and r is the radius of the top of the plunger, is the Poisson's ratio of the plunger sleeve material, is the elastic modulus of the plunger sleeve material;

[0011] Step 2, plunger design;

[0012] The plunger includes a top axial section, a tail axial section, and a variable-diameter axial section between the top axial section and the tail axial section;

[0013] The length of the top axial section is ; The length of the tail axial section is ;

[0014] The length of the variable-diameter axial section is ;

[0015] The radius of the variable-diameter axial section is ;

[0016] Wherein is a constant, and the value range is 2.0~2.4; is a constant, and the value range is 1.0~2.2; is a constant, and the value range is 1.6~3.0; x is the radial distance from the top of the plunger to the calculation position, and r(x) is the radius of the plunger at the calculation position, is the Poisson's ratio of the plunger material, is the elastic modulus of the plunger material, is a constant, and the value range is 0.18-0.21.

[0017] Step 3, through finite element simulation, optimize the plunger diameter and the corresponding axial length related parameters, optimize the plunger sleeve outer diameter parameter, ensure that the plunger outer diameter expansion and the deformation trend of the plunger sleeve are coordinated, and the gap between the plunger and the plunger sleeve is always kept within the sealing allowable range under high pressure working condition.

[0018] Further improvement or preferred embodiment of the foregoing plunger pair gap sealing design method, the step 3 specifically includes:

[0019] A, determining the plunger stroke curve according to the camshaft speed and the cam profile;

[0020] B. According to the device pressure design requirements, the plunger stroke curve, the plunger sleeve pressure cavity pressure curve is calculated;

[0021] C. According to the plunger sleeve material properties, the preliminary structure, the pressure curve, the stroke curve, the plunger sleeve strain is calculated;

[0022] D. Adjust the parameters ~ , ~ Obtain the length of each section of the plunger sleeve ~ And the corresponding thickness ~ ;

[0023] E. Repeat steps C~D until the plunger corresponding to the plunger sleeve inner wall position deformation amount change value is less than the design value;

[0024] F. Based on the plunger sleeve deformation, the plunger material properties, the pressure, the stroke, the corresponding transverse strain of each axial position of the plunger is calculated;

[0025] G. Adjust the parameters ~ Obtain the radius of each axial position of the middle part of the plunger - And the axial length of the plunger ~ ;

[0026] H. Repeat steps F~G until the plunger movement plunger and plunger sleeve gap is less than the design value.

[0027] Further improvement or preferred embodiment of the foregoing plunger pair gap sealing design method, the step E specifically includes: according to the plunger sleeve material properties, the preliminary structure, the pressure curve, the stroke curve, the plunger sleeve strain is calculated; judge whether the plunger corresponding to the plunger sleeve inner wall position deformation amount change value is less than the design value during the plunger movement;

[0028] If less than, output the plunger sleeve size, if not less than, adjust the parameters ~ , ~ Obtain the length of each section of the plunger sleeve ~ And the corresponding thickness ~ And recalculate the updated deformation amount change value, until the plunger corresponding to the plunger sleeve inner wall position deformation amount change value is less than the design value.

[0029] The application also provides a plunger pair gap sealing design method, and the step H specifically comprises: calculating the transverse strain amount corresponding to each axial position of the plunger based on the plunger sleeve deformation amount, the plunger material attribute, the pressure and the stroke; judging whether the gap between the plunger and the plunger sleeve during the plunger movement is less than the design value, and if yes, outputting the plunger design parameter, and if not, adjusting the parameter ~ obtaining the radius of each axial position of the middle part of the plunger - and the axial length of the plunger ~ , until the gap between the plunger and the plunger sleeve during the plunger movement is less than the design value.

[0030] Further improvement or preferred implementation steps of the foregoing plunger pair gap sealing test method, comprising: installing a micro flowmeter on the low-pressure liquid pipe of the plunger sleeve, testing the sealing performance of the plunger and the plunger sleeve by measuring the liquid flow in the low-pressure liquid pipe; under normal circumstances, the low-pressure liquid pipe supplies liquid to the liquid collecting tank to maintain the lubrication of the plunger movement, when the sealing performance of the plunger sleeve and the plunger is poor, the high-pressure liquid flows from the plunger gap to the low-pressure liquid pipe through the liquid collecting tank, and the leakage amount can be obtained after being tested by the micro flowmeter.

[0031] The application also provides a plunger pair gap sealing test system, comprising an oil supply assembly, a driving assembly, a detection assembly and an analysis assembly.

[0032] The oil supply assembly comprises a high-pressure pump, a proportional overflow valve and an oil supply pipeline; the driving assembly comprises a hydraulic motor, a variable frequency pump, a variable frequency speed regulation motor and a frequency converter; the detection assembly comprises an oil film thickness sensor, an oil film pressure sensor, an oil film temperature sensor, a signal conditioner, a rotating speed sensor and an oil supply pressure sensor; and the analysis assembly comprises a data acquisition card and a computer.

[0033] The high-pressure pump supplies oil to the plunger pair through the proportional overflow valve, and the oil supply pressure is detected by the oil supply pressure sensor; the frequency converter controls the rotating speed of the variable frequency speed regulation motor, the variable frequency speed regulation motor drives the variable pump as the power output of the hydraulic motor, the hydraulic motor drives the plunger pair to move, and the rotating speed sensor detects the output rotating speed of the hydraulic motor; the oil film thickness sensor, the oil film pressure sensor and the oil film temperature sensor are used to obtain the oil film parameters of the plunger pair; the signal conditioner obtains the data of the oil film thickness sensor, the oil film pressure sensor and the oil film temperature sensor for conditioning analysis to extract effective data; and the data acquisition card obtains the corresponding parameter data of the proportional overflow valve control parameter, the signal conditioner, the rotating speed sensor, the oil supply pressure sensor, the frequency converter and the rotating speed sensor to generate the plunger pair running state data.

[0034] Its beneficial effects are:

[0035] The present application changes the structure design of the plunger and the plunger sleeve, so that the outer diameter of the plunger can be self-adaptively expanded under high pressure, the deformation amount of the inner diameter of the plunger sleeve is offset in real time, the matching gap between the plunger and the plunger sleeve is maintained stable, and the high pressure sealing problem is fundamentally solved. A micro probe is installed in the low pressure liquid pipe of the plunger sleeve, and the sealing performance of the plunger pair is tested by testing the liquid flow direction of the low pressure liquid pipe. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a flow diagram of the plunger pair gap sealing design method;

[0037] Figure 2 is a schematic diagram of the plunger pair structure in the embodiment;

[0038] Figure 3 is a schematic diagram of the plunger sleeve structure in the embodiment;

[0039] Figure 4 is a schematic diagram of the structure of the plunger in the embodiment;

[0040] Figure 5 is a pressure curve of the pressure chamber of the plunger sleeve and a stroke curve of the plunger;

[0041] Figure 6 is a calculation diagram of the radial deformation amount of the plunger and the plunger sleeve before optimization;

[0042] Figure 7 is a calculation diagram of the radial deformation amount of the plunger and the plunger sleeve after optimization;

[0043] Figure 8 is a schematic diagram of the plunger pair gap sealing test system;

[0044] The reference signs include:

[0045] 1 plunger; 2 plunger sleeve; 3 pressure chamber; 4 plunger gap; 5 liquid collecting groove; 6 oil return hole; 7 micro flowmeter. DETAILED DESCRIPTION

[0046] The present application will be described in detail below in combination with specific embodiments.

[0047] In view of the defects that the matching gap of the plunger pair of the existing high pressure hydraulic element is increased and the liquid leakage amount is significantly increased due to the expansion of the inner diameter of the plunger sleeve under high pressure working condition, the present application provides a structure design method for improving the sealing performance of the high pressure hydraulic element, and a sealing performance test method and system thereof.

[0048] As shown in Figure 1 , Figure 2 , the present application provides a plunger pair gap sealing design method, which comprises the following steps:

[0049] Step 1: plunger sleeve design;

[0050] like Figure 3 As shown, the plunger sleeve includes a length The first shaft segment, length The second shaft segment, length The third axis segment, length The fourth shaft section; the inner hole of the plunger sleeve is a cylindrical surface with equal diameter;

[0051] in is a constant ranging from 1.5 to 2.0; Hy is the distance from the top dead center of the plunger to the upper edge of the plunger sleeve; is a constant ranging from 1.1 to 1.3; S is the plunger stroke; is a constant ranging from 1.0 to 1.2; D is the inner diameter of the plunger sleeve; L is the total length of the plunger sleeve;

[0052] The thickness of the plunger sleeve corresponding to each shaft section of the plunger sleeve is

[0053] ;

[0054] in is the thickness of the mth shaft segment, and the value of m is 1, 2, 3, or 4; is a constant with a value range of 0.7~1.1; P is the maximum pressure of the plunger pressure chamber, and r is the radius of the plunger top; is the Poisson's ratio of the plunger sleeve material, is the elastic modulus of the plunger sleeve material;

[0055] Step 2: plunger design;

[0056] like Figure 4 As shown, the plunger includes a top shaft segment and a tail shaft segment with the same radius, and a diameter-reducing shaft segment located between the top shaft segment and the tail shaft segment;

[0057] Top shaft length ; Tail shaft length ;

[0058] Length of reducing shaft section ;

[0059] Radius of reducing shaft section ;

[0060] in is a constant, ranging from 2.0 to 2.4; is a constant, ranging from 1.0 to 2.2; is a constant with a value range of 1.6~3.0; x is the radial distance from the top of the plunger to the calculated position, r(x) is the plunger radius at the calculated position, is the Poisson's ratio of the plunger material, Elastic modulus of the plunger material, is a constant, and the value range is 0.18-0.21.

[0061] Step 3, through finite element simulation, the plunger diameter and the corresponding axial length related parameters are optimized, the plunger sleeve outer diameter parameters are optimized, the plunger outer diameter expansion and the deformation trend of the plunger sleeve are coordinated, and the plunger and the plunger sleeve gap is always kept within the sealing allowable range under high pressure working condition.

[0062] Further improvement or preferred embodiment of the foregoing plunger pair gap sealing design method, the step 3 specifically includes:

[0063] A, according to the camshaft speed, cam profile to determine the plunger stroke curve;

[0064] B, according to the design requirements of equipment pressure, plunger stroke curve, the plunger sleeve pressure cavity pressure curve is calculated, as shown in Figure 5 ;

[0065] C, according to the plunger sleeve material properties, preliminary structure, pressure curve, stroke curve to calculate the plunger sleeve strain;

[0066] D, adjusting parameters ~ 、 ~ obtain the length of each section of the plunger sleeve ~ and the corresponding thickness ~ ;

[0067] E, repeat steps C~D, until the deformation amount change value of the plunger corresponding to the plunger sleeve inner wall position in the plunger movement process is less than the design value;

[0068] Specifically includes: according to the plunger sleeve material properties, preliminary structure, pressure curve, stroke curve to calculate the plunger sleeve strain; judge whether the deformation amount change value of the plunger corresponding to the plunger sleeve inner wall position in the plunger movement process is less than the design value;

[0069] If less than, output the plunger sleeve size, if not less than, adjust the parameters ~ 、 ~ obtain the length of each section of the plunger sleeve ~ and the corresponding thickness ~ and recalculate the updated deformation amount change value, until the deformation amount change value of the plunger corresponding to the plunger sleeve inner wall position is less than the design value.

[0070] F, calculating the transverse strain of each axial position of the plunger based on the deformation of the plunger sleeve, the material properties of the plunger, the pressure, and the stroke;

[0071] G, adjusting parameters ~ obtaining the radius of each axial position of the middle part of the plunger - , and the axial length of the plunger ~ ;

[0072] H, repeating steps F-G until the gap between the plunger and the plunger sleeve is less than the design value.

[0073] wherein step H specifically comprises: calculating the transverse strain of each axial position of the plunger based on the deformation of the plunger sleeve, the material properties of the plunger, the pressure, and the stroke; determining whether the gap between the plunger and the plunger sleeve is less than the design value when the plunger moves, and if so, outputting the design parameters of the plunger, and if not, adjusting the parameters ~ obtaining the radius of each axial position of the middle part of the plunger - , and the axial length of the plunger ~ until the gap between the plunger and the plunger sleeve is less than the design value.

[0074] Based on the above structure and design scheme, a certain plunger pair is designed and optimized, and the results are shown in FIGS. Figure 6 、 Figure 7 .

[0075] The application also provides a plunger pair gap sealing detection method, comprising:

[0076] A micro flowmeter is installed on the plunger sleeve low-pressure liquid pipe, and the sealing performance of the plunger and the plunger sleeve is tested by measuring the flow of liquid in the low-pressure liquid pipe.

[0077] Under normal circumstances, the low-pressure liquid pipe supplies liquid to the liquid collecting tank to maintain the lubrication of the plunger movement, and when the sealing performance of the plunger sleeve and the plunger is poor, the high-pressure liquid flows from the plunger gap to the low-pressure liquid pipe through the liquid collecting tank, and the leakage amount can be obtained after being tested by the micro flowmeter.

[0078] In order to further improve and enrich the above detection method, obtain more complete and clear plunger sleeve operation parameters, and complete the test analysis in each direction, the application also provides a plunger pair gap sealing test system, as shown in FIG. Figure 8 The main structure includes an oil supply assembly, a driving assembly, a detection assembly, and an analysis assembly.

[0079] The oil supply assembly comprises a high-pressure pump, a proportional overflow valve and an oil supply pipeline; the driving assembly comprises a hydraulic motor, a variable frequency pump, a variable frequency motor and a frequency converter; the detection assembly comprises an oil film thickness sensor, an oil film pressure sensor, an oil film temperature sensor, a signal conditioner, a rotating speed sensor and an oil supply pressure sensor; and the analysis assembly comprises a data acquisition card and a computer.

[0080] The high-pressure pump supplies oil to the plunger pair through the proportional overflow valve, and the oil supply pressure is detected by the oil supply pressure sensor; the frequency converter controls the rotating speed of the variable frequency motor, the variable frequency motor drives the variable pump as a power output of the hydraulic motor, the hydraulic motor drives the plunger pair to move, and the rotating speed sensor detects the output rotating speed of the hydraulic motor; the oil film thickness sensor, the oil film pressure sensor and the oil film temperature sensor are used to obtain the oil film parameters of the plunger pair; the signal conditioner obtains the data of the oil film thickness sensor, the oil film pressure sensor and the oil film temperature sensor, and performs conditioning analysis to extract effective data; the data acquisition card obtains the corresponding parameter data of the proportional overflow valve control parameter, the signal conditioner, the rotating speed sensor, the oil supply pressure sensor, the frequency converter and the rotating speed sensor to generate the running state data of the plunger pair.

[0081] The test system can be used as a signal monitoring center and a data processing platform through the computer, and as a control center to output driving signals to various components. During the test experiment, the data acquisition card realizes the acquisition of the analog parameter of the oil film of the friction pair and the system working condition parameters of the test bench, the computer realizes the real-time visual display of the oil film parameters through the analysis and processing of the measured data, and at the same time, the acquisition card port controls the driver to drive the components to be executed, including the proportional loading adjustment of the proportional overflow valve and the variable frequency speed control of the motor.

[0082] In particular, in order to meet the analysis and observation of the running data of the plunger pair during the test process of the plunger pair, a corresponding management control program or functional module should also be equipped in the computer to meet the following needs:

[0083] Data interaction module: used for establishing a data real-time display and output process or function, which can visually output the corresponding data charts during the test process and complete the data entry and export during the test analysis process of the test system;

[0084] Historical data storage module: used for storing the historical test analysis data of the plunger pair and the running parameter data of the test system itself, so as to analyze and process the historical data.

[0085] System parameter control and adjustment module: used for establishing a control interface for the running parameters of each functional module in the test system, so as to accurately control each direction content during the test process;

[0086] The early warning protection module is used for monitoring and managing abnormal parameters and states during the operation of the test system, timely issuing early warning information when abnormal information is monitored, and providing emergency stop and automatic or passive protection functions when necessary.

[0087] Compared with the prior art, the core advantage of the application is that:

[0088] 1. Dynamic self-adaptive sealing:

[0089] The clearance is compensated in real time through the deformation of the plunger and plunger sleeve structure, without relying on external complex hydraulic or mechanical adjusting devices, and the structure is simple and reliable.

[0090] 2. High-pressure leakage is significantly reduced:

[0091] Under the super-high pressure working condition of 160 MPa or more, the clearance between the plunger and the plunger sleeve can be reduced by 30%~50%, the liquid leakage is reduced by 40%~60%, and the equipment efficiency is effectively improved.

[0092] 3. The stability of the supply pressure is improved:

[0093] Reducing the leakage amount reduces the fluctuation range of the hydraulic supply pressure, and improves the accuracy and stability of the equipment pressure supply.

[0094] 4. Cost and process advantages:

[0095] Only the machining process of the plunger and the plunger sleeve needs to be optimized, without complex structural modification of the remaining parts, and the manufacturing cost is controllable.

[0096] 5. Prolong the service life of the parts:

[0097] The gap control can reduce the erosion and wear of the mating surface by high-pressure liquid, and release local stress by elastic deformation, thereby delaying fatigue failure.

[0098] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not a limitation on the protection scope of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A plunger pair clearance seal design method, characterized in that: The steps include: Step 1: plunger sleeve design; The plunger sleeve includes a length The first shaft segment, length The second shaft segment, length The third axis segment, length The fourth shaft section; the inner hole of the plunger sleeve is a cylindrical surface with equal diameter; in is a constant ranging from 1.5 to 2.0; Hy is the distance from the top dead center of the plunger to the upper edge of the plunger sleeve; is a constant ranging from 1.1 to 1.3; S is the plunger stroke; is a constant ranging from 1.0 to 1.2; D is the inner diameter of the plunger sleeve; L is the total length of the plunger sleeve; The thickness of the plunger sleeve corresponding to each shaft section of the plunger sleeve is: ； in is the thickness of the mth axial segment, where m takes values ​​of 1, 2, 3, or 4; is a constant with a value range of 0.7~1.1; P is the maximum pressure of the plunger pressure chamber, r is the radius of the plunger top, is the Poisson's ratio of the plunger sleeve material, is the elastic modulus of the plunger sleeve material; Step 2: plunger design; The plunger includes a top shaft section and a tail shaft section with the same radius, and a diameter-reducing shaft section located between the top shaft section and the tail shaft section; Top shaft length ; Tail shaft length ; Length of reducing shaft section ; Radius of reducing shaft section ; in is a constant, ranging from 2.0 to 2.4; is a constant, ranging from 1.0 to 2.2; is a constant with a value range of 1.6~3.0; x is the radial distance from the top of the plunger to the calculated position, r(x) is the plunger radius at the calculated position, is the Poisson's ratio of the plunger material, is the elastic modulus of the plunger material, is a constant, ranging from 0.18 to 0.21; Step 3: Through finite element simulation, optimize the plunger diameter and the corresponding axial length parameters, optimize the plunger sleeve outer diameter parameters, ensure that the plunger outer diameter expansion is coordinated with the deformation trend of the plunger sleeve, and keep the gap between the plunger and the plunger sleeve within the sealing allowable range under high pressure conditions.

2. The plunger pair clearance seal design method according to claim 1, characterized in that: The step 3 specifically includes: A. Determine the plunger stroke curve based on the camshaft speed and cam profile; B. Calculate the plunger sleeve pressure chamber pressure curve based on the equipment pressure design requirements and plunger stroke curve; C. Calculate the strain of the plunger sleeve based on the plunger sleeve material properties, preliminary structure, pressure curve, and stroke curve; D. Adjust parameters ~ 、 ~ Get the length of each section of the plunger sleeve ~ The corresponding thickness ~ ; E. Repeat steps C to D until the change in the deformation of the inner wall of the plunger sleeve corresponding to the plunger during the movement of the plunger is less than the design value; F. Calculate the lateral strain corresponding to each axial position of the plunger based on the deformation of the plunger sleeve, the plunger material properties, pressure, and stroke; G. Adjust parameters ~ Get the radius of each axial position in the middle of the plunger - , and the axial length of the plunger ~ ; H. Repeat steps F to G until the clearance between the plunger and the plunger sleeve is less than the design value.

3. The plunger pair clearance seal design method according to claim 1, characterized in that: The step E specifically includes: calculating the strain of the plunger sleeve according to the material properties, preliminary structure, pressure curve, and stroke curve of the plunger sleeve; determining whether the change in the deformation of the inner wall position of the plunger sleeve corresponding to the plunger during the movement of the plunger is less than the design value; If it is smaller than, the plunger sleeve size is output; if it is not smaller than, the parameters are adjusted. ~ 、 ~ Get the length of each section of the plunger sleeve ~ The corresponding thickness ~ The deformation change value is recalculated and updated until the deformation change value of the inner wall position of the plunger sleeve corresponding to the plunger is less than the design value.

4. The plunger pair clearance seal design method according to claim 1, characterized in that: The step H specifically includes: calculating the lateral strain corresponding to each axial position of the plunger based on the deformation of the plunger sleeve, the plunger material properties, pressure, and stroke; judging whether the gap between the plunger and the plunger sleeve is less than the design value when the plunger moves, and outputting the plunger design parameters if it is less than the design value; and adjusting the parameters if it is not less than the design value. ~ Get the radius of each axial position in the middle of the plunger - and the axial length of the plunger ~ , until the clearance between the plunger and the plunger sleeve is less than the design value when the plunger moves.

5. The plunger pair clearance sealing test method according to claim 1, characterized in that: The method comprises the following steps: installing a micro flow meter on the low-pressure liquid pipe of the plunger sleeve, and testing the sealing performance of the plunger and the plunger sleeve by measuring the liquid flow in the low-pressure liquid pipe; the low-pressure liquid pipe supplies liquid to the liquid collecting tank to keep the movement of the plunger lubricated; when the sealing performance between the plunger sleeve and the plunger is poor, the high-pressure liquid flows from the plunger gap through the liquid collecting tank to the low-pressure liquid pipe, and the leakage amount is obtained after testing with the micro flow meter.

6. A testing system for the plunger pair clearance sealing testing method according to claim 5, characterized in that: Including oil supply components, drive components, detection components, and analysis components; The oil supply components include: high-pressure pump, proportional relief valve, oil supply pipeline; the drive components include: hydraulic motor, variable frequency pump, variable frequency speed motor, inverter; the detection components include: oil film thickness sensor, oil film pressure sensor, oil film temperature sensor, signal conditioner, speed sensor, oil supply pressure sensor; the analysis components include: data acquisition card, computer; The high-pressure pump supplies oil to the plunger pair through the proportional relief valve, and the oil supply pressure is detected by the oil supply pressure sensor; the frequency converter controls the speed of the variable frequency speed regulation motor, the variable frequency speed regulation motor drives the variable pump as the power output of the hydraulic motor, the hydraulic motor drives the plunger pair to move, and the speed sensor detects the output speed of the hydraulic motor; the oil film thickness sensor, the oil film pressure sensor, and the oil film temperature sensor are used to obtain the oil film parameters of the plunger pair; the signal conditioner obtains the data of the oil film thickness sensor, the oil film pressure sensor, and the oil film temperature sensor for analysis and extraction of valid data; the data acquisition card obtains the corresponding parameter data of the proportional relief valve control parameters, the signal conditioner, the speed sensor, the oil supply pressure sensor, the frequency converter, and the speed sensor to generate the operating status data of the plunger pair.

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