WO2023147740A1 - 一种检测和评估液压缸内泄漏的恒值参数法及其检测装置 - Google Patents

一种检测和评估液压缸内泄漏的恒值参数法及其检测装置 Download PDF

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WO2023147740A1
WO2023147740A1 PCT/CN2022/136676 CN2022136676W WO2023147740A1 WO 2023147740 A1 WO2023147740 A1 WO 2023147740A1 CN 2022136676 W CN2022136676 W CN 2022136676W WO 2023147740 A1 WO2023147740 A1 WO 2023147740A1
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pressure
hydraulic cylinder
leakage
standard
cavity
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PCT/CN2022/136676
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English (en)
French (fr)
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徐兵
李旭光
张军辉
纵怀志
许昕蕾
黄伟迪
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浙江大学
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Publication of WO2023147740A1 publication Critical patent/WO2023147740A1/zh
Priority to US18/408,440 priority Critical patent/US12092135B2/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
    • F15B19/005—Fault detection or monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B11/00—Servomotor systems without provision for follow-up action; Circuits therefor
    • F15B11/08—Servomotor systems without provision for follow-up action; Circuits therefor with only one servomotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B13/00—Details of servomotor systems ; Valves for servomotor systems
    • F15B13/02—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors
    • F15B13/04—Fluid distribution or supply devices characterised by their adaptation to the control of servomotors for use with a single servomotor
    • F15B13/0401—Valve members; Fluid interconnections therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B19/00—Testing; Calibrating; Fault detection or monitoring; Simulation or modelling of fluid-pressure systems or apparatus not otherwise provided for
    • F15B19/002—Calibrating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B20/00—Safety arrangements for fluid actuator systems; Applications of safety devices in fluid actuator systems; Emergency measures for fluid actuator systems
    • F15B20/005—Leakage; Spillage; Hose burst
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B21/00—Common features of fluid actuator systems; Fluid-pressure actuator systems or details thereof, not covered by any other group of this subclass
    • F15B21/08—Servomotor systems incorporating electrically operated control means
    • F15B21/087—Control strategy, e.g. with block diagram
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
    • G01M3/00—Investigating fluid-tightness of structures
    • G01M3/02—Investigating fluid-tightness of structures by using fluid or vacuum
    • G01M3/26—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors
    • G01M3/32—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators
    • G01M3/3236—Investigating fluid-tightness of structures by using fluid or vacuum by measuring rate of loss or gain of fluid, e.g. by pressure-responsive devices, by flow detectors for containers, e.g. radiators by monitoring the interior space of the containers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/20507—Type of prime mover
    • F15B2211/20515—Electric motor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/20—Fluid pressure source, e.g. accumulator or variable axial piston pump
    • F15B2211/205—Systems with pumps
    • F15B2211/2053—Type of pump
    • F15B2211/20538—Type of pump constant capacity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/40—Flow control
    • F15B2211/415—Flow control characterised by the connections of the flow control means in the circuit
    • F15B2211/41527—Flow control characterised by the connections of the flow control means in the circuit being connected to an output member and a directional control valve
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/505—Pressure control characterised by the type of pressure control means
    • F15B2211/50509—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means
    • F15B2211/50518—Pressure control characterised by the type of pressure control means the pressure control means controlling a pressure upstream of the pressure control means using pressure relief valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/50—Pressure control
    • F15B2211/515—Pressure control characterised by the connections of the pressure control means in the circuit
    • F15B2211/5157—Pressure control characterised by the connections of the pressure control means in the circuit being connected to a pressure source and a return line
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/60—Circuit components or control therefor
    • F15B2211/63—Electronic controllers
    • F15B2211/6303—Electronic controllers using input signals
    • F15B2211/6306—Electronic controllers using input signals representing a pressure
    • F15B2211/6313—Electronic controllers using input signals representing a pressure the pressure being a load pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B2211/00—Circuits for servomotor systems
    • F15B2211/80—Other types of control related to particular problems or conditions
    • F15B2211/86—Control during or prevention of abnormal conditions
    • F15B2211/863—Control during or prevention of abnormal conditions the abnormal condition being a hydraulic or pneumatic failure
    • F15B2211/864—Failure of an output member, e.g. actuator or motor failure

Definitions

  • the invention belongs to the technical field of hydraulic cylinders, and in particular relates to a constant value parameter method and a detection device for evaluating leakage in a hydraulic cylinder.
  • Hydraulic cylinder leakage is divided into external leakage and internal leakage. It is a common failure of hydraulic cylinders. Performance and efficiency of hydraulic systems. The incidence of internal leakage failure is high and difficult to detect. When the internal leakage exceeds the standard, the hydraulic cylinder will not work normally.
  • the internal leakage test in the hydraulic cylinder industry is generally carried out in accordance with the national standard GB/T15622-2005 "Hydraulic Cylinder Test Method” and the industry standard JB/T10205-2010 "Hydraulic Cylinder”.
  • the test method is as follows: work on the hydraulic cylinder under test The cavity is input with oil, pressurized to the nominal pressure, and the leakage through the piston to the unpressurized cavity is measured.
  • the industry currently uses the measuring cup measurement method to detect the leakage in the hydraulic cylinder.
  • the specific operation method is: pressurize the rodless cavity or the rod cavity to the nominal pressure, and use the measuring cup to measure the oil port of the unpressurized cavity for a certain period of time. The volume of internal leakage oil.
  • the detection method is inefficient. Taking the internal leakage standard of a double-acting hydraulic cylinder as an example, the double-acting hydraulic cylinder (bore diameter) stipulated in the standard ) The internal leakage range is 0.03mL/min-4.2mL/min, and the leakage is extremely small. Assuming that the leakage in a certain hydraulic cylinder is 0.01mL/min, if 5mL of oil leakage is to be detected, the detection time will take more than 8 hours, and the detection efficiency is extremely low. At the same time, because the hydraulic oil has a certain viscosity, a small amount of leaked hydraulic oil often adheres to the inner wall of the hydraulic cylinder and nozzle, which further increases the difficulty of detection and cannot meet the needs of rapid quality detection of batch products.
  • the detection standard has poor versatility.
  • the current standard only stipulates the internal leakage of 19 groups of standard size hydraulic cylinders, and "one standard for one cylinder".
  • manufacturers often produce hydraulic cylinders of non-standard size for users according to the requirements of application occasions and installation space.
  • the existing testing standards are difficult to cover the detection of non-standard size hydraulic cylinders.
  • the present invention provides an efficient, simple and universal constant value parameter method and detection device for detecting and evaluating leakage in a hydraulic cylinder.
  • a constant value parameter method for detecting and evaluating leakage in a hydraulic cylinder comprising the following steps:
  • Step (1) measuring the accurate pressure drop value ⁇ p of the leakage in the hydraulic cylinder, that is, the pressure drop value of the high-pressure chamber caused by the internal leakage of the hydraulic cylinder;
  • Step (2) judging whether the hydraulic cylinder under test meets the standard: if the product of the accurate pressure drop value ⁇ p of the leakage in the hydraulic cylinder and the corresponding hydraulic stroke, that is, ⁇ p ⁇ L, is less than the standard parameter C for evaluating the leakage in the hydraulic cylinder, it is Among them, Q is the standard value of leakage in the hydraulic cylinder, K is the elastic modulus of oil, t is the test time of leakage measurement in the hydraulic cylinder, L is the stroke of the hydraulic cylinder, D is the inner diameter of the hydraulic cylinder, and the leakage in the hydraulic cylinder meets the standard , otherwise, it does not meet the standard.
  • the accurate pressure drop value ⁇ p measurement of the leakage in the hydraulic cylinder includes the following steps:
  • Step (1.1) measuring the pressure drop of the control chamber: supply oil to the control chamber first, and wait until the pressure reaches the rated test pressure, so that the control chamber is in a pressure-holding state. At this time, the pressure of the control chamber is p1-1. After pressing for a predetermined time, the pressure in the control cavity is p2-1 at this time, and the difference between p1-1 and p2-1 is the pressure drop ⁇ p_1 in the control cavity;
  • Step (1.2) measuring the pressure drop of the hydraulic cylinder: first remove the control chamber in step (1.1) through the disassembly joint of the pipeline, and replace the hydraulic cylinder on the same hydraulic testing test bench, and then add the pressure drop to the high pressure capacity of the hydraulic cylinder. Cavity supply oil, drive the piston rod of the hydraulic cylinder to stretch out to the end of the stroke, and when the pressure reaches the rated test pressure, the hydraulic cylinder is in the pressure maintaining state. At this time, the pressure of the high pressure chamber of the hydraulic cylinder is p1-2.
  • the pressure of the high-pressure chamber of the hydraulic cylinder is p2-2 at this time, and the difference between p1-2 and p2-2 is the pressure drop ⁇ p_2 of the high-pressure chamber of the hydraulic cylinder;
  • the motor before starting the pressure-holding test for the control cavity in step (1.1), the motor is started to drive the hydraulic pump, and the reversing valve is reversing for a test run, so as to eliminate residual air in the hydraulic test bench.
  • step (1.1) adopts: close the second cut-off valve of the oil return circuit, adjust the reversing valve to work in the left position, the hydraulic pump supplies oil to the controlled cavity through the reversing valve, and measure the control through the pressure sensor.
  • Cavity pressure when the pressure reaches the rated test pressure, that is, the nominal pressure of the hydraulic cylinder, the reversing valve works in the neutral position, so that the control cavity is blocked, the control cavity is in a pressure-holding state, and the first stop valve is closed at the same time.
  • the cavity is locked, at this time the pressure in the standard cavity is the same as the pressure in the control cavity, that is, p1-1, after a predetermined time of pressure holding, the pressure in the control cavity drops to p2-1 at this time, and the standard cavity is directly measured by the differential pressure sensor
  • the difference between cavity pressure p1-1 and control cavity pressure p2-1, this pressure difference is the control cavity pressure drop ⁇ p_1.
  • step (1.2) adopts: start the motor to drive the hydraulic pump to work, adjust the reversing valve to work in the left position after the hydraulic cylinder is tested for exhaust, and the hydraulic pump feeds the high-pressure chamber of the hydraulic cylinder through the reversing valve.
  • Supply oil drive the piston rod of the hydraulic cylinder to extend to the end of the stroke, and measure the pressure of the high-pressure chamber of the hydraulic cylinder through the pressure sensor.
  • the cylinder is locked, the hydraulic cylinder is in a pressure-holding state, and the first stop valve is closed at the same time, and the standard cavity is blocked. At this time, the pressure in the standard cavity is the same as the pressure in the high-pressure cavity of the hydraulic cylinder, that is, p1-2.
  • the pressure drop of the high-pressure chamber of the hydraulic cylinder is p2-2, and the difference between the standard chamber pressure p1-2 and the pressure of the high-pressure chamber of the hydraulic cylinder p2-2 is directly measured by the differential pressure sensor.
  • This pressure difference is the hydraulic cylinder Pressure drop ⁇ p_2 in the high pressure chamber.
  • a detection device suitable for the constant value parameter method for detecting and evaluating leakage in a hydraulic cylinder including:
  • a reversing valve the oil inlet communicates with the oil outlet of the hydraulic pump
  • the tested piece has a cavity with an oil inlet and outlet, communicates with the reversing valve through the oil inlet and outlet, and jointly forms an oil circuit;
  • a pipeline disassembly joint which is detachably connected to the oil inlet and outlet of the tested piece;
  • a pressure sensor is arranged on the inlet and outlet oil passage, and is used to measure the internal pressure of the tested piece.
  • a standard chamber, a first cut-off valve and a differential pressure sensor respectively located between the standard chamber and the tested piece are connected to the oil inlet and outlet.
  • the tested part is a hydraulic cylinder or a control cavity.
  • the oil inlet and outlet are connected with a second cut-off valve located between the control chamber and the pipeline disassembly joint.
  • the pressure signal is simple, easy to measure, and has high precision, and is more sensitive to leakage reflections. Therefore, the pressure drop caused by internal leakage of the hydraulic cylinder can be accurately obtained in a short period of time. , high measurement efficiency, greatly reducing the test time;
  • This detection method is applicable to various types of hydraulic cylinders, which can meet the detection requirements of non-standard size hydraulic cylinders, and has strong versatility;
  • the control chamber is set to eliminate the influence of leakage in the hydraulic system pipeline, reversing valve and pressure test joint connection, etc., which improves the accuracy of internal leakage detection, and the test bench has a simple structure and low cost.
  • Fig. 1 is a structural schematic diagram of a hydraulic cylinder leakage detection and evaluation device as a test group in an embodiment of the present invention
  • Fig. 2 is a structural schematic diagram of a hydraulic cylinder leakage detection and evaluation device used as a control group in an embodiment of the present invention
  • Fig. 3 is a flowchart of a constant value parameter method for detecting and evaluating leakage in a hydraulic cylinder in an embodiment of the present invention.
  • a detection device suitable for the constant value parameter method of detecting and evaluating leakage in a hydraulic cylinder including: a motor 10, a hydraulic pump 9, a reversing valve 7, a measured Components, pressure sensor 6 and pipeline disassembly joint 2.
  • the hydraulic pump 9 is coaxially connected with the motor 10, and the hydraulic pump 9 is driven by the motor 10 to provide power oil for the tested hydraulic cylinder 1 to perform test operations such as trial operation according to national standards.
  • the oil inlet of reversing valve 7 is communicated with the oil outlet of hydraulic pump 9, and reversing valve 7 can adopt three-position four-way reversing valve 7.
  • the tested piece has a cavity with an oil inlet and outlet, and communicates with the reversing valve 7 through the oil inlet and outlet, and together constitutes an oil circuit; as shown in Figure 1, in one embodiment, the tested piece is a hydraulic cylinder 1 or a control Chamber 12.
  • the leakage detection and evaluation device in the hydraulic cylinder 1 is used as the test group.
  • the pressure sensor 6 is arranged on the inlet and outlet oil passages for measuring the pressure in the tested part, that is, the pressure sensor 6 is used for measuring the pressure of the high-pressure chamber of the hydraulic cylinder 1 under test and the pressure of the reference chamber 12 .
  • the pipeline disassembly joint 2 is detachably connected to the oil inlet and outlet of the tested piece.
  • the oil inlet and outlet are connected with a standard chamber 4 and the first cut-off chambers respectively located between the standard chamber 4 and the tested piece.
  • Valve 5 and differential pressure sensor 3 Valve 5 and differential pressure sensor 3.
  • An overflow valve 8 located between the reversing valve 7 and the hydraulic pump 9 is connected to the oil inlet and outlet.
  • the structure of the standard chamber 4 is similar to that of the hydraulic cylinder 1, but there is no structure such as a piston and a piston rod, and there is no internal leakage at all.
  • the first cut-off valve 5 plays the role of completely blocking the oil circuit, and there is no oil leakage.
  • the differential pressure sensor 3 measures the pressure difference between the high-pressure chamber of the hydraulic cylinder 1 under test and the standard chamber 4, and the pressure difference is the pressure drop value of the high-pressure chamber of the hydraulic cylinder 1 under test.
  • the range of the pressure sensor 6 is greatly reduced, and the measurement accuracy of internal leakage is improved.
  • the standard chamber 4 and the high-pressure chamber of the hydraulic cylinder 1 under test perform simultaneous real-time pressure maintenance, further eliminating the influence of ambient temperature changes on the pressure drop value.
  • the second cut-off valve 11 between the control chamber 12 and the pipeline disassembly joint 2 is connected on the oil outlet, and the second cut-off valve 11 plays a role
  • the oil circuit is completely blocked, and there is no oil leakage.
  • the control chamber 12 is used as a control group for the hydraulic cylinder 1 to be tested.
  • the control cavity 12 is similar in structure to the hydraulic cylinder 1, but there is no structure such as a piston and a piston rod, and there is no internal leakage at all.
  • the difference between the pressure drop of the tested hydraulic cylinder 1 and the control cavity 12 is the pressure drop of the tested hydraulic cylinder 1 due to internal leakage.
  • a constant value parameter method for detecting and evaluating leakage in a hydraulic cylinder comprising the following steps:
  • Step (1) measuring the accurate pressure drop value ⁇ p of the internal leakage of the hydraulic cylinder 1, that is, the pressure drop value of the high-pressure chamber caused by the internal leakage of the hydraulic cylinder;
  • Step (2) judging whether the hydraulic cylinder 1 under test meets the standard: if the product of the accurate pressure drop value ⁇ p of the leakage in the hydraulic cylinder 1 and the corresponding hydraulic stroke, that is, ⁇ p ⁇ L, is less than the standard parameter C for evaluating the leakage in the hydraulic cylinder 1, that is Then the leakage in the hydraulic cylinder 1 meets the standard, otherwise, it does not meet the standard.
  • the constant value parameters for detecting and evaluating the leakage in the hydraulic cylinder 1 are derived as follows:
  • the rodless chamber of the hydraulic cylinder 1 under test is filled with a volume of V 1 and a pressure of p 1 , and the leakage after time t is V L .
  • the pressure of the rodless chamber of the hydraulic cylinder 1 under test is p 2
  • the corresponding oil volume is V 2
  • Q L the amount of internal leakage
  • ⁇ p ⁇ p 1 - ⁇ p 2 ;
  • Q is the standard value of leakage in hydraulic cylinder 1, which is selected by the model of hydraulic cylinder 1 according to the industry standard JB/T10205-2010 "Hydraulic Cylinder 1"
  • hydraulic cylinder 1 internal leakage measurement test time is adjusted according to the size of hydraulic cylinder 1
  • L is the stroke of hydraulic cylinder 1
  • D is the inner diameter of hydraulic cylinder 1, and the value is determined according to the specific hydraulic cylinder 1 model .
  • this embodiment proposes a constant value parameter method for detecting and evaluating the leakage in the hydraulic cylinder 1.
  • the constant value parameter C is set as a standard parameter for evaluating the leakage in the hydraulic cylinder 1.
  • the oil used for the constant value parameter C The liquid elastic modulus K is selected according to the oil quality and the test environment, and the measurement time t is appropriately adjusted according to the size and model of the hydraulic cylinder 1.
  • the constant value parameter C can be taken as 2000MPa ⁇ mm at this time. If the product of the pressure drop caused by the internal leakage of the hydraulic cylinder 1 obtained through the control experiment and the corresponding hydraulic stroke is less than 2000MPa ⁇ mm, the internal leakage of the hydraulic cylinder 1 meets the standard, otherwise it does not meet the standard.
  • the accurate pressure drop value ⁇ p measurement of the leakage in the hydraulic cylinder 1 includes the following steps:
  • Step (1.1) measuring the pressure drop of the control chamber 12: supply oil to the control chamber 12 first, and wait until the pressure reaches the rated test pressure, so that the control chamber 12 is in a pressure-holding state, and the pressure of the control chamber 12 is p1 at this time -1, after holding the pressure for a predetermined time, the pressure of the control chamber 12 at this time is p2-1, and the difference between p1-1 and p2-1 is the pressure drop ⁇ p_1 of the control chamber 12;
  • Step (1.2) measuring the pressure drop of hydraulic cylinder 1: first remove the control chamber 12 in step (1.1) through the disassembly joint 2 of the pipeline, and replace the hydraulic cylinder 1 on the same hydraulic test bench, The high-pressure chamber of cylinder 1 is supplied with oil, and the piston rod of hydraulic cylinder 1 is driven to extend to the end of the stroke. When the pressure reaches the rated test pressure, hydraulic cylinder 1 is kept in a pressure-holding state.
  • the pressure of the high-pressure chamber of hydraulic cylinder 1 is p1 -2, after holding the pressure for the same predetermined time as the control chamber 12 in step (1.1), the pressure in the high-pressure chamber of hydraulic cylinder 1 is p2-2, and the difference between p1-2 and p2-2 is the hydraulic pressure Pressure drop ⁇ p_2 of cylinder 1 high pressure chamber;
  • the motor 10 drives the hydraulic pump 9 to work, and the reversing valve 7 is reversing for trial operation, so as to get rid of residual air in the hydraulic test bench .
  • step (1.1) adopts: start the pressure maintaining test, close the second cut-off valve 11 of the oil return circuit, adjust the reversing valve 7 to work in the left position, and the hydraulic pump 8 will give the controlled capacity through the reversing valve 7.
  • Cavity 12 is supplied with oil, and the pressure of the control chamber is measured by the pressure sensor 6. After the pressure reaches the rated test pressure (nominal pressure of the hydraulic cylinder) and becomes stable, the reversing valve 7 works in the neutral position, so that the control chamber 12 can be reliably blocked. The control chamber 12 is in a pressure maintaining state. At the same time, close the first stop valve 5 to reliably lock the standard chamber 4.
  • the pressure in the standard chamber 4 is the same as the pressure in the control chamber 12, that is, p1-1.
  • the control chamber is now 12
  • the pressure drop is p2-1
  • the difference between the pressure p1-1 of the standard chamber 4 and the pressure p2-1 of the control chamber 12 is directly measured by the differential pressure sensor 3, and this pressure difference is the pressure drop ⁇ p_1 of the control chamber.
  • the pressure drop value obtained from the pressure holding test is all caused by the leakage of the hydraulic test bench pipeline, reversing valve and pressure test joint connection.
  • step (1.2) adopts: start the motor 10 to drive the hydraulic pump 9 to work, and after the tested hydraulic cylinder 1 is exhausted during the test run, adjust the reversing valve 7 to work in the left position, and the hydraulic pump 9 is fed through the reversing valve 7.
  • the rodless chamber of the hydraulic cylinder 1 under test supplies oil, drives the piston rod of the hydraulic cylinder 1 under test to extend to the end of the stroke, and measures the pressure of the high-pressure chamber of the hydraulic cylinder under test through the pressure sensor 6 until the pressure reaches the rated test pressure (nominal pressure of the hydraulic cylinder) After the pressure) is stable, the reversing valve 7 is switched to the neutral position, so that the hydraulic cylinder 1 is reliably locked, and the hydraulic cylinder 1 under test is in a pressure-holding state. At the same time, close the first stop valve 5 to reliably lock the standard chamber 4. At this time, the pressure in the standard chamber 4 is the same as the pressure in the high-pressure chamber of the hydraulic cylinder 1, that is, p1-2.
  • the pressure drop of the high-pressure chamber is p2-2, and the difference between the pressure p1-2 of the standard chamber 4 and the pressure p2-2 of the high-pressure chamber of the hydraulic cylinder 1 is directly measured by the differential pressure sensor 3, and this pressure difference is the hydraulic cylinder 1 Pressure drop ⁇ p_2 in the high pressure chamber.
  • the pressure drop value ⁇ p_2 of the hydraulic cylinder measured in the test minus the pressure drop value ⁇ p_1 caused by the internal leakage of the hydraulic test bench pipeline, reversing valve and pressure test joint connection is the accurate pressure drop of the hydraulic cylinder under test.
  • Value ⁇ p, ie ⁇ p ⁇ p_2 ⁇ p_1.
  • the pressure signal is simple, easy to measure, and has high precision, and is more sensitive to leakage reflections. Therefore, the pressure drop caused by internal leakage of the hydraulic cylinder can be accurately obtained in a short period of time. , high measurement efficiency, greatly reducing the test time;
  • This detection method is applicable to various types of hydraulic cylinders, which can meet the detection requirements of non-standard size hydraulic cylinders, and has strong versatility;
  • the control chamber is set to eliminate the influence of leakage in the hydraulic system pipeline, reversing valve and pressure test joint connection, etc., which improves the accuracy of internal leakage detection, and the test bench has a simple structure and low cost.

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Abstract

公开了一种检测和评估液压缸内泄漏的恒值参数法，包括以下步骤：步骤(1)、测量液压缸内泄漏的准确压降值Δp；步骤(2)、判断被测液压缸是否符合标准：若液压缸内泄漏的准确压降值Δp与对应液压行程的乘积，即Δp×L小于评估液压缸内泄漏的标准参数C，则液压缸内泄漏符合标准，反之，则不符合标准。还公开了适用于这种检测和评估液压缸内泄漏的恒值参数法的检测装置。

Description

一种检测和评估液压缸内泄漏的恒值参数法及其检测装置 技术领域
本发明属于液压缸技术领域，具体涉及一种评估液压缸内泄漏的恒值参数法以及检测装置。
背景技术
液压缸泄漏分为外泄漏和内泄漏，是液压缸常见的一种故障，其中，内泄漏是指液压缸内部的油液由高压腔向低压腔泄漏，导致液压缸的输出力下降，严重影响液压系统的性能和效率。内泄漏故障发生率高且难以察觉，内泄漏量超标时会导致造成液压缸不能正常工作。
当前液压缸行业在进行内泄漏测试时，普遍是按照国标GB/T15622-2005《液压缸试验方法》和行业标准JB/T10205-2010《液压缸》执行，试验方法如下：在被测液压缸工作腔输入油液，加压至公称压力，测量经活塞泄漏至未加压腔的泄漏量。据调研，行业目前多采用量杯测量法检测液压缸内泄漏量，具体操作方法为：将无杆腔或有杆腔加压至公称压力，用量杯在未加压一腔的油口测量一定时间内泄漏油的体积。
国标和行标的测试方法在实际应用中存在如下问题：
(1)检测方法效率低。以双作用液压缸内泄漏标准为例，标准中规定的双作用液压缸(缸径
Figure PCTCN2022136676-appb-000001
)内泄漏范围为0.03mL/min-4.2mL/min，泄漏量极小。假设某一液压缸内泄漏量为0.01mL/min，若要检测到5mL的泄漏油液，则检测时间需要8个小时以上，检测效率极低。同时，由于液压油具有一定的粘度，泄漏的微量液压油常粘附在液压缸及管口内壁面，进一步加大了检测难度，无法满足批量产品质量快速检测需求。
(2)检测标准通用性差。现行标准中仅规定了19组标准尺寸液压缸的内泄漏量，且“一缸一标准”。但在实际应用中，制造商常常根据应用场合、安装空间等需求，为用户生产非标尺寸的液压缸，现有检测标准难以覆盖非标尺寸液 压缸的检测。
综上所述，现有液压缸内泄漏检测方法效率低下。
发明内容
针对上述现有技术存在的问题，本发明提供一种高效、简单、通用的检测和评估液压缸内泄漏的恒值参数法以及检测装置。
本发明的目的是通过以下技术方案来实现的：
在一实施例中，提供了一种检测和评估液压缸内泄漏的恒值参数法，包括以下步骤：
步骤(1)、测量液压缸内泄漏的准确压降值Δp，即液压缸由于内泄漏而引起高压容腔的压力下降值；
步骤(2)、判断被测液压缸是否符合标准：若液压缸内泄漏的准确压降值Δp与对应液压行程的乘积，即Δp×L小于评估液压缸内泄漏的标准参数C，即为
Figure PCTCN2022136676-appb-000002
其中，Q为液压缸内泄漏量的标准值，K为油液弹性模量，t为液压缸内泄漏测量试验时间，L为液压缸行程，D为液压缸内径，则液压缸内泄漏符合标准，反之，则不符合标准。
在一实施例中，液压缸内泄漏的准确压降值Δp测量包括以下步骤：
步骤(1.1)、测量对照容腔压降：先向对照容腔供油，待其压力达到额定试验压力，使对照容腔处于保压状态，此时对照容腔的压力为p1-1，保压预定时间后，此时对照容腔的压力为p2-1，p1-1与p2-1的差值，即为对照容腔压降Δp_1；
步骤(1.2)、测量液压缸压降：先通过管路拆装接头拆卸掉步骤(1.1)中的对照容腔，并且在同一液压检测试验台上换上液压缸，然后向液压缸的高压容腔供油，驱动液压缸活塞杆伸出到行程末端，待其压力达到额定试验压力，将液压缸处于保压状态，此时液压缸高压容腔的压力为p1-2，保压与步骤(1.1)中对照容腔相同的预定时间后，此时液压缸高压容腔的压力为p2-2，p1-2与p2-2的差值，即为液压缸高压容腔压降Δp_2；
步骤(1.3)、计算液压缸内泄漏的准确压降值Δp：液压缸内泄漏的准确压降 值Δp＝Δp_2-Δp_1。
在一实施例中，在步骤(1.1)中对对照容腔开始保压试验之前，启动电机驱动液压泵工作，换向阀换向试运行，以排除液压试验台内的残留空气。
在一实施例中，步骤(1.1)中采用：关闭回油路第二截止阀，调节换向阀工作于左位，液压泵通过换向阀给被对照容腔供油，通过压力传感器测量对照容腔压力，待压力达到额定试验压力，即液压缸公称压力，换向阀换向工作于中位，使对照容腔闭锁，对照容腔处于保压状态，同时关闭第一截止阀，对标准容腔进行闭锁，此时标准容腔内压力与对照容腔压力相同，即p1-1，保压预定时间后，此时对照容腔压力降为p2-1，由差压传感器直接测量标准容腔压力p1-1与对照容腔压力p2-1的差值，此压力差值即为对照容腔压降Δp_1。
在一实施例中，步骤(1.2)中采用：启动电机驱动液压泵工作，在液压缸试运行排气后，调节换向阀工作于左位，液压泵通过换向阀给液压缸高压容腔供油，驱动液压缸活塞杆伸出到行程末端，通过压力传感器测量液压缸高压容腔压力，待压力达到额定试验压力，即液压缸公称压力，换向阀换向工作于中位，使液压缸闭锁，液压缸处于保压状态，同时关闭第一截止阀，对标准容腔进行闭锁，此时标准容腔内压力与液压缸高压容腔压力相同，即p1-2，保压预定时间后，此时液压缸高压容腔压力降为p2-2，由差压传感器直接测量标准容腔压力p1-2与液压缸高压容腔压力p2-2的差值，此压力差值即为液压缸高压容腔压降Δp_2。
在一实施例中，提供了一种适用于检测和评估液压缸内泄漏的恒值参数法的检测装置，包括：
电机；
液压泵，与所述电机同轴连接；
换向阀，进油口与所述液压泵的出油口连通；
被测件，具有带有进出油口的容腔且通过进出油路与所述换向阀连通且共同构成油回路；
管路拆装接头，可拆卸地连接在所述被测件的进出油口处；以及
压力传感器，设置在所述进出油路上，用于测量所述被测件内压力。
在一实施例中，所述进出油路上连接有标准容腔以及分别都位于标准容腔和被测件之间的第一截止阀和差压传感器。
在一实施例中，所述被测件为液压缸或对照容腔。
在一实施例中，所述进出油路上连接有位于所述对照容腔和所述管路拆装接头之间的第二截止阀。
本发明实施例的检测和评估液压缸内泄漏的恒值参数法以及装置至少具有如下有益效果：
1、相比传统采用量筒进行微小泄漏流量检测的方法，压力信号简单易测精度高，而且对泄漏反映更为敏感，因此在较短时间内即可准确获得液压缸因内泄漏导致的压降，测量效率高，大大缩减了试验时间；
2、只需将检测所得压降值与该液压缸行程的乘积与恒值参数参数C做比较，便可直接判断其内泄漏是否符合标准，省去了复杂的换算与繁琐的查表，简单直观、易用性强；
3、该检测方法适用于各种型号的液压缸，可以满足非标尺寸液压缸的检测需求，通用性强；
4、设置标准容腔，通过差压传感器直接测量标准容腔与被测液压缸高压容腔(对照容腔)压差，缩短了压力传感器量程，提高了压降信号的测量精度。同时，试验检测时标准容腔与被测液压缸高压容腔(对照容腔)进行同步实时保压，进一步排除了环境温度变化对压降值的影响。
5、设置对照容腔排除液压系统管路、换向阀和试压接头连接等处泄漏的影响，提高了内泄漏检测精度，且试验台结构简单，成本低。
附图说明
图1为本发明一实施例中作为试验组的液压缸内泄漏检测和评估装置的结构示意图；
图2为本发明一实施例中作为对照组的液压缸内泄漏检测和评估装置的结构示意图；
图3为本发明一实施例中检测和评估液压缸内泄漏的恒值参数法的流程图。
具体实施方式
下面结合附图和具体实施例对本发明作进一步详细说明。
如图1所示，在一实施例中，提供了一种适用于检测和评估液压缸内泄漏的恒值参数法的检测装置，包括：电机10、液压泵9、换向阀7、被测件、压力传感器6和管路拆装接头2。
液压泵9与电机10同轴连接，液压泵9由电机10驱动，为被测液压缸1按照国家标准进行试运行等测试项目时提供动力油。
换向阀7的进油口与液压泵9的出油口连通，换向阀7可以采用三位四通换向阀7。被测件具有带有进出油口的容腔且通过进出油路与换向阀7连通且共同构成油回路；如图1所示，在一实施例中，被测件为液压缸1或对照容腔12。在被测件采用液压缸1时，该液压缸1内泄漏检测和评估装置作为试验组，三位四通换向阀7工作于左位时，被测液压缸1活塞杆伸出；三位四通换向阀7工作于右位时，被测液压缸1活塞杆缩回；三位四通电磁换向阀7工作于中位时，被测液压缸1双向闭锁，被测液压缸1活塞可靠停止；如图2所示，而在被测件采用对照容腔12时，该液压缸1内泄漏检测和评估装置作为对照组。
压力传感器6设置在进出油路上，用于测量被测件内压力，即压力传感器6用于测量被测液压缸1高压容腔的压力和对照容腔12的压力。
管路拆装接头2可拆卸地连接在被测件的进出油口处。
如图1和图2所示，在一实施例中，在对照组和试验组中，进出油路上连接有标准容腔4以及分别都位于标准容腔4和被测件之间的第一截止阀5和差压传感器3。进出油路上连接有位于换向阀7和液压泵9之间的溢流阀8。
其中，标准容腔4与液压缸1结构类似，但没有活塞与活塞杆等结构，完全不存在内泄漏。
第一截止阀5起到油路完全闭锁的作用，无油液泄漏。
差压传感器3测量被测液压缸1高压容腔与标准容腔4的压力差值，该压力差值即为被测液压缸1高压容腔压降值。与直接记录被测液压缸1高压容腔保 压压力相比，大大缩小了压力传感器6量程，提升了内泄漏测量精度。同时，试验检测时标准容腔4与被测液压缸1高压容腔进行同步实时保压，进一步排除了环境温度变化对压降值的影响。
如图2所示，在一实施例中，在对照组中，出油路上连接有位于对照容腔12和管路拆装接头2之间的第二截止阀11，第二截止阀11起到油路完全闭锁的作用，无油液泄漏。
对照容腔12作为被测液压缸1的对照组进行试验。为了准确测得液压缸1内泄漏产生的压降值，在进行液压缸1内泄漏检测和评估试验之前，需要对对照容腔12进行保压试验，模拟液压缸1完全无内泄漏的试验状况，从而排除液压试验台管路、换向阀7和试压接头连接等处泄漏的影响。该对照容腔12与液压缸1结构类似，但没有活塞与活塞杆等结构，完全不存在内泄漏。被测液压缸1与对照容腔12压降的差值即为被测液压缸1因内泄漏产生的压降。
在一实施例中，提供了一种检测和评估液压缸内泄漏的恒值参数法，包括以下步骤：
步骤(1)、测量液压缸1内泄漏的准确压降值Δp，即液压缸由于内泄漏而引起高压容腔的压力下降值；
步骤(2)、判断被测液压缸1是否符合标准：若液压缸1内泄漏的准确压降值Δp与对应液压行程的乘积，即Δp×L小于评估液压缸1内泄漏的标准参数C，即为
Figure PCTCN2022136676-appb-000003
则液压缸1内泄漏符合标准，反之，则不符合标准。
其中，检测和评估液压缸1内泄漏的恒值参数推导如下：
被测液压缸1无杆腔充入体积为V 1，压力为p 1，经过时间t后泄漏量为V L，此时被测液压缸1无杆腔压力为p 2，对应油液体积为V 2，所以，被测液压缸1内泄漏油液体积V L＝V 1-V 2，内泄漏量记为Q L。根据油液弹性模量
Figure PCTCN2022136676-appb-000004
可得：
Figure PCTCN2022136676-appb-000005
Figure PCTCN2022136676-appb-000006
通过对密闭容腔进行保压试验，排除液压系统其他元件内泄漏的干扰。令液压缸1保压一定时间后压降值为Δ？ 1，对照容腔12压降值为Δ？ 2，液压缸1内泄漏引起的压降值Δp为：
Δp＝Δp 1-Δp 2；
根据内泄漏流量计算公式：
Figure PCTCN2022136676-appb-000007
对公式进行变换得：
Figure PCTCN2022136676-appb-000008
其中：Q为液压缸1内泄漏量的标准值，由液压缸1型号根据行业标准JB/T10205-2010《液压缸1》选取；K为油液弹性模量，一般纯油取K＝1.4～2.0GPa，混入空气后一般取0.7～1.4GPa；液压缸1内泄漏测量试验时间根据液压缸1尺寸调整；L为液压缸1行程，D为液压缸1内径，根据具体液压缸1型号取值。
通过计算可以得出液压缸1由内泄漏导致的压降Δp(Δp＝Δp 1-Δp 2)与液压缸1行程L的乘积近似为一恒值参数C。
基于上述讨论，本实施例提出了一种检测和评估液压缸1内泄漏的恒值参数法，将恒值参数C设置为评估液压缸1内泄漏的标准参数，其中恒值参数C所用的油液弹性模量K根据油液品质与测试环境进行选取，测量时间t根据液压缸1尺寸型号进行适当调整。
例如，取K＝1.5GPa，t＝60min，将国标GB/T15622-2005《液压缸1试验方法》和行业标准JB/T10205-2010《液压缸1》中双作用液压缸1内泄漏量标准表进行换算，此时恒值参数C可取2000MPa·mm。若通过对照实验所得液压缸1因内泄漏导致的压降与对应液压行程的乘积小于2000MPa·mm，液压缸 1内泄漏符合标准，反之不符合标准。
表1 K＝1.5GPa，t＝60min时的恒值参数参数C
Figure PCTCN2022136676-appb-000009
如图3所示，在一实施例中，液压缸1内泄漏的准确压降值Δp测量包括以下步骤：
步骤(1.1)、测量对照容腔12压降：先向对照容腔12供油，待其压力达到额定试验压力，使对照容腔12处于保压状态，此时对照容腔12的压力为p1-1，保压预定时间后，此时对照容腔12的压力为p2-1，p1-1与p2-1的差值，即为对照容腔12压降Δp_1；
步骤(1.2)、测量液压缸1压降：先通过管路拆装接头2拆卸掉步骤(1.1)中的对照容腔12，并且在同一液压检测试验台上换上液压缸1，然后向液压缸1的高压容腔供油，驱动液压缸1活塞杆伸出到行程末端，待其压力达到额定试验压力，将液压缸1处于保压状态，此时液压缸1高压容腔的压力为p1-2，保压与步骤(1.1)中对照容腔12相同的预定时间后，此时液压缸1高压容腔的压力为p2-2，p1-2与p2-2的差值，即为液压缸1高压容腔压降Δp_2；
步骤(1.3)、计算液压缸1内泄漏的准确压降值Δp：液压缸1内泄漏的准确压降值Δp＝Δp_2-Δp_1。
在一实施例中，在步骤(1.1)中对对照容腔12开始保压试验之前，启动电机10驱动液压泵9工作，换向阀7换向试运行，以排除液压试验台内的残留空气。
在一实施例中，步骤(1.1)中采用：开始保压试验，关闭回油路第二截止阀11，调节换向阀7工作于左位，液压泵8通过换向阀7给被对照容腔12供油，通过压力传感器6测量对照容腔压力，待压力达到额定试验压力(液压缸公称压力)并平稳后，换向阀7换向工作于中位，使对照容腔12可靠闭锁，对照容腔12处于保压状态。同时关闭第一截止阀5，对标准容腔4进行可靠闭锁，此时标准容腔4内压力与对照容腔12压力相同，即p1-1，保压一定时间t后，此时对照容腔12压力降为p2-1，由差压传感器3直接测量标准容腔4压力p1-1与对照容腔12压力p2-1的差值，此压力差值即为对照容腔压降Δp_1。对其进行保压试验所得的压降值全部由液压试验台管路、换向阀和试压接头连接等处的泄漏引起。
进一步地，步骤(1.2)中采用：启动电机10驱动液压泵9工作，在被测液压缸1试运行排气后，调节换向阀7工作于左位，液压泵9通过换向阀7给被测液压缸1的无杆腔供油，驱动被测液压缸1活塞杆伸出到行程末端，通过压力传感器6测量被测液压缸高压容腔压力，待压力达到额定试验压力(液压缸公称压力)并平稳后，换向阀7换向工作于中位，使液压缸1可靠闭锁，被测液压缸1处于保压状态。同时关闭第一截止阀5，对标准容腔4进行可靠闭锁，此时标准容腔4内压力与液压缸1高压容腔压力相同，即p1-2，保压预定时间后，此时液压缸1高压容腔压力降为p2-2，由差压传感器3直接测量标准容腔4压力p1-2与液压缸1高压容腔压力p2-2的差值，此压力差值即为液压缸1高压容腔压降Δp_2。
试验所测得的液压缸的压降值Δp_2减去液压试验台管路、换向阀和试压接头连接处等内泄漏造成的压降值Δp_1即为被测液压缸内泄漏的准确压降值Δp，即Δp＝Δp_2-Δp_1。
本发明实施例的检测和评估液压缸内泄漏的恒值参数法以及装置至少具有如下有益效果：
1、相比传统采用量筒进行微小泄漏流量检测的方法，压力信号简单易测精度高，而且对泄漏反映更为敏感，因此在较短时间内即可准确获得液压缸因内泄漏导致的压降，测量效率高，大大缩减了试验时间；
2、只需将检测所得压降值与该液压缸行程的乘积与恒值参数参数C做比较，便可直接判断其内泄漏是否符合标准，省去了复杂的换算与繁琐的查表，简单直观、易用性强；
3、该检测方法适用于各种型号的液压缸，可以满足非标尺寸液压缸的检测需求，通用性强；
4、设置标准容腔，通过差压传感器直接测量标准容腔与被测液压缸高压容腔(对照容腔)压差，缩短了压力传感器量程，提高了压降信号的测量精度。同时，试验检测时标准容腔与被测液压缸高压容腔(对照容腔)进行同步实时保压，进一步排除了环境温度变化对压降值的影响。
5、设置对照容腔排除液压系统管路、换向阀和试压接头连接等处泄漏的影响，提高了内泄漏检测精度，且试验台结构简单，成本低。
上面结合附图对本发明实施例作了详细说明，但是本发明不限于上述实施例，在所述技术领域普通技术人员所具备的知识范围内，还可以在不脱离本发明宗旨的前提下作出各种变化。此外，在不冲突的情况下，本发明的实施例及实施例中的特征可以相互组合。

Claims (8)

  1. 一种检测和评估液压缸内泄漏的恒值参数法，其特征在于，包括以下步骤：
    步骤(1)、测量液压缸内泄漏的准确压降值Δp，即液压缸由于内泄漏而引起高压容腔的压力下降值，具体包括以下步骤：
    步骤(1.1)、测量对照容腔压降：先向对照容腔供油，待其压力达到额定试验压力，使对照容腔处于保压状态，此时对照容腔的压力为p1-1，保压预定时间后，此时对照容腔的压力为p2-1，p1-1与p2-1的差值，即为对照容腔压降Δp_1；
    步骤(1.2)、测量液压缸压降：先通过管路拆装接头拆卸掉步骤(1.1)中的对照容腔，并且在同一液压检测试验台上换上液压缸，然后向液压缸的高压容腔供油，驱动液压缸活塞杆伸出到行程末端，待其压力达到额定试验压力，将液压缸处于保压状态，此时液压缸高压容腔的压力为p1-2，保压与步骤(1.1)中对照容腔相同的预定时间后，此时液压缸高压容腔的压力为p2-2，p1-2与p2-2的差值，即为液压缸高压容腔压降Δp_2；
    步骤(1.3)、计算液压缸内泄漏的准确压降值Δp：液压缸内泄漏的准确压降值Δp＝Δp_2-Δp_1；
    步骤(2)、判断被测液压缸是否符合标准：若液压缸内泄漏的准确压降值Δp与对应液压行程的乘积，即Δp×L小于评估液压缸内泄漏的标准参数C，即为
    Figure PCTCN2022136676-appb-100001
    其中，Q为液压缸内泄漏量的标准值，K为油液弹性模量，t为液压缸内泄漏测量试验时间，L为液压缸行程，D为液压缸内径，则液压缸内泄漏符合标准，反之，则不符合标准。
  2. 根据权利要求1所述的检测和评估液压缸内泄漏的恒值参数法，其特征在于，在步骤(1.1)中对对照容腔开始保压试验之前，启动电机驱动液压泵工作，换向阀换向试运行，以排除液压试验台内的残留空气。
  3. 根据权利要求2所述的检测和评估液压缸内泄漏的恒值参数法，其特征在于，步骤(1.1)中采用：关闭回油路第二截止阀，调节换向阀工作于左位，液压泵通过换向阀给被对照容腔供油，通过压力传感器测量对照容腔压力，待压 力达到额定试验压力，即液压缸公称压力，换向阀换向工作于中位，使对照容腔闭锁，对照容腔处于保压状态，同时关闭第一截止阀，对标准容腔进行闭锁，此时标准容腔内压力与对照容腔压力相同，即p1-1，保压预定时间后，此时对照容腔压力降为p2-1，由差压传感器直接测量标准容腔压力p1-1与对照容腔压力p2-1的差值，此压力差值即为对照容腔压降Δp_1。
  4. 根据权利要求1所述的检测和评估液压缸内泄漏的恒值参数法，其特征在于，步骤(1.2)中采用：启动电机驱动液压泵工作，在液压缸试运行排气后，调节换向阀工作于左位，液压泵通过换向阀给液压缸高压容腔供油，驱动液压缸活塞杆伸出到行程末端，通过压力传感器测量液压缸高压容腔压力，待压力达到额定试验压力，即液压缸公称压力，换向阀换向工作于中位，使液压缸闭锁，液压缸处于保压状态，同时关闭第一截止阀，对标准容腔进行闭锁，此时标准容腔内压力与液压缸高压容腔压力相同，即p1-2，保压预定时间后，此时液压缸高压容腔压力降为p2-2，由差压传感器直接测量标准容腔压力p1-2与液压缸高压容腔压力p2-2的差值，此压力差值即为液压缸高压容腔压降Δp_2。
  5. 一种适用于权利要求1—4中任意一项权利要求所述的检测和评估液压缸内泄漏的恒值参数法的检测装置，其特征在于，包括：
    电机；
    液压泵，与所述电机同轴连接；
    换向阀，进油口与所述液压泵的出油口连通；
    被测件，具有带有进出油口的容腔且通过进出油路与所述换向阀连通且共同构成油回路；
    管路拆装接头，可拆卸地连接在所述被测件的进出油口处；以及
    压力传感器，设置在所述进出油路上，用于测量所述被测件内压力。
  6. 根据权利要求5所述的检测装置，其特征在于，所述进出油路上连接有标准容腔以及分别都位于标准容腔和被测件之间的第一截止阀和差压传感器。
  7. 根据权利要求5所述的检测装置，其特征在于，所述被测件为液压缸或对照容腔。
  8. 根据权利要求7所述的检测装置，其特征在于，所述进出油路上连接有位于所述对照容腔和所述管路拆装接头之间的第二截止阀。
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