A device and method for detecting leakage in a hydraulic cylinder

Abstract

A device for detecting leakage in a hydraulic cylinder comprises a second control valve, a detection device, a metering hydraulic cylinder, a first hydraulic pipeline, a second hydraulic pipeline, a third hydraulic pipeline and a high-pressure oil source; a displacement sensor is provided on the metering hydraulic cylinder, and a detection channel and a liquid filling compensation channel are provided in the metering hydraulic cylinder in parallel; the liquid filling compensation channel is connected to a third hydraulic pipeline for communicating with the oil channel cavity of the hydraulic cylinder to be detected; the detection channel is connected to an oil port of the high-pressure oil source through the first hydraulic pipeline; a first control valve is provided on the first hydraulic pipeline; the liquid filling compensation channel is connected to another oil port of the high-pressure oil source through the second hydraulic pipeline; a second control valve is provided on the second hydraulic pipeline; the detection device is respectively connected to the displacement sensor, the first control valve, the second control valve and the high-pressure oil source in communication. The present invention also proposes a detection method for the device for detecting leakage in a hydraulic cylinder. The present invention is simple to operate and greatly improves the efficiency and accuracy of detecting leakage in a hydraulic cylinder.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic cylinder detection, and in particular to a hydraulic cylinder internal leakage detection device and a detection method. Background Art

[0002] The detection of internal leakage in hydraulic cylinder tests has always been a difficult point in hydraulic test detection. The qualified value of hydraulic cylinder internal leakage index stipulated by national standards is very small. JB / T10205-2010 "Hydraulic Cylinder" stipulates that the internal leakage index of a hydraulic cylinder with an inner diameter of 100 is only 0.4ml / min, and the internal leakage index of a hydraulic cylinder with an inner diameter of 160 is only 1.2ml / min. Most of the hydraulic cylinders of construction machinery are within this range. There are two main detection methods currently in use:

[0003] 1. Use the top-to-bottom or dead-gear iron method to fix the piston rod of the hydraulic cylinder at a certain position, and the oil pump pressurizes the rodless chamber of the hydraulic cylinder. Use a measuring cup or precision worm flowmeter or precision gear flowmeter to detect the leakage at the outlet of the rod chamber;

[0004] 2. After the hydraulic cylinder piston rod moves to a certain position, seal the oil ports of the two chambers of the hydraulic cylinder, apply tension or thrust to the end of the cylinder piston rod to generate a sufficient pressure difference between the two chambers of the hydraulic cylinder, and calculate the leakage by detecting the displacement of the cylinder piston rod. At present, various existing flow sensors and flow meters cannot detect a flow rate of 1ml / min with an accuracy of 2.5%. Therefore, the current method of detecting leakage in hydraulic cylinder tests has to use a measuring cup to measure the leakage within 10-30 minutes; or use a displacement sensor to detect the retraction amount of the hydraulic cylinder piston rod within 1-2 hours;

[0005] The disadvantages of these two methods are that they are time-consuming and inaccurate. Therefore, the present application proposes a device and method for detecting leakage in a hydraulic cylinder. Summary of the invention

[0006] (I) Purpose of the invention

[0007] In order to solve the technical problems existing in the background technology, the present invention proposes a hydraulic cylinder internal leakage detection device and detection method. The present invention is simple to operate and greatly improves the efficiency and accuracy of hydraulic cylinder internal leakage detection to meet the needs of hydraulic cylinder internal leakage detection.

[0008] (II) Technical solution

[0009] In order to solve the above problems, the present invention provides a hydraulic cylinder internal leakage detection device, comprising a second control valve, a detection device, a metering hydraulic cylinder, a first hydraulic pipeline, a second hydraulic pipeline, a third hydraulic pipeline and a high-pressure oil source for conveying hydraulic oil;

[0010] A displacement sensor for detecting the displacement of the telescopic end of the metering hydraulic cylinder is provided on the metering hydraulic cylinder, and a detection channel and a liquid filling compensation channel are provided in the metering hydraulic cylinder; wherein the detection channel and the liquid filling compensation channel are arranged in parallel; the liquid filling compensation channel is communicated with a third hydraulic pipeline for communicating with the oil channel cavity of the hydraulic cylinder to be detected;

[0011] One end of the first hydraulic pipeline is connected to an oil port of the high-pressure oil source, the first hydraulic pipeline is communicated with the detection channel, and a first control valve is provided on the first hydraulic pipeline;

[0012] One end of the second hydraulic pipeline is connected to another oil port of the high-pressure oil source, the second hydraulic pipeline is communicated with the liquid filling compensation channel, and a second control valve is provided on the second hydraulic pipeline;

[0013] The detection device is communicatively connected to the displacement sensor, the first control valve, the second control valve and the high-pressure oil source respectively.

[0014] Preferably, the metering hydraulic cylinder comprises two sets of piston rods, two sets of end covers and a cylinder body;

[0015] A piston is provided in a sealing and sliding manner in the cylinder body;

[0016] The two sets of end covers are respectively provided with two sets of oil ports for connecting with the first hydraulic pipeline and the second hydraulic pipeline, and the two sets of end covers are respectively provided with two sets of guide sleeves along the axis direction thereof, and the two sets of end covers are respectively connected to the two ends of the cylinder body;

[0017] The two groups of piston rods respectively pass through the two groups of guide sleeves through interference fit and extend into the cylinder body, and the two groups of piston rods are both connected to the pistons; wherein the sliding part on the displacement sensor is connected to any group of piston rods.

[0018] Preferably, it also includes a connecting plate; one end of the connecting plate is connected to the piston rod, and the other end of the connecting plate is connected to the sliding part on the displacement sensor.

[0019] Preferably, it also includes a sealing member; a mounting groove is provided on the outer peripheral surface of the piston along its circumferential direction; and the sealing member is interference-fittedly sleeved in the mounting groove.

[0020] Preferably, the displacement sensor is an incremental grating sensor or a magnetostrictive displacement sensor.

[0021] The present invention also proposes a detection method for a hydraulic cylinder internal leakage detection device, comprising the following specific steps:

[0022] S1. Fix the hydraulic cylinder to be tested at the stroke position where the leakage in the hydraulic cylinder is to be tested;

[0023] S2. Adjust the piston of the metering hydraulic cylinder to the starting position of the metering stroke. At this time, the metering stroke displayed on the detection device is zero;

[0024] S3, installing the first hydraulic pipeline, the second hydraulic pipeline, the third hydraulic pipeline, the metering hydraulic cylinder, the hydraulic cylinder to be tested and the high-pressure oil source;

[0025] S4, close the first control valve, adjust the pressure of the high-pressure oil source to the test pressure and keep it unchanged; open the second control valve, and the high-pressure oil source fills the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be tested with high-pressure oil. At this time, the pressure in the oil channel cavity of the hydraulic cylinder to be tested is the same as the test pressure;

[0026] S5. After the pressure in the oil channel cavity of the hydraulic cylinder to be tested is stabilized to the test pressure, first open the first control valve and then close the second control valve;

[0027] S6. The displacement sensor detects the displacement of the piston of the metering hydraulic cylinder and sends the detected displacement signal to the detection device; the detection device analyzes and calculates the internal leakage of the hydraulic cylinder to be detected.

[0028] Preferably, the piston rod of the hydraulic cylinder to be tested in S1 is fixed by a mechanical positioning device.

[0029] Preferably, in S5, the first control valve is opened 10 to 30 seconds after the pressure in the oil channel cavity of the hydraulic cylinder to be tested stabilizes to the test pressure.

[0030] The above technical solution of the present invention has the following beneficial technical effects:

[0031] In the present invention, when in use, the first hydraulic pipeline is connected with the high-pressure oil source and the detection channel in the metering hydraulic cylinder, and then the second hydraulic pipeline is connected with the high-pressure oil source and the liquid filling compensation channel in the metering hydraulic cylinder, and the third hydraulic pipeline is used to connect the liquid filling compensation channel in the metering hydraulic cylinder with the oil channel cavity of the hydraulic cylinder to be detected; the high-pressure oil source supplies oil to the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be detected through the second hydraulic pipeline, until the oil pressure in the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be detected from the second hydraulic pipeline is the same as the test oil pressure, and the oil pressure in the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be detected from the second hydraulic pipeline is balanced; when the first control valve is opened and the second control valve is closed, the displacement of the telescopic end of the metering hydraulic cylinder is detected by the displacement sensor to calculate the internal leakage of the hydraulic cylinder to be detected, and the operation is simple and convenient to use;

[0032] In the present invention, the internal sealing of the metering hydraulic cylinder is good, and its internal leakage is zero. The displacement of the piston of the metering hydraulic cylinder is strictly proportional to the volume of the hydraulic oil entering. This precision detection device can be called a micro-flow metering cylinder. A flow rate of less than 1ml / min can immediately cause the piston to produce a displacement sufficient to be detected, greatly improving the detection accuracy and detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The present invention provides a schematic structural diagram of a metering hydraulic cylinder in a hydraulic cylinder internal leakage detection device.

[0034] Figure 2 This is a principle block diagram of a hydraulic cylinder internal leakage detection device proposed by the present invention.

[0035] Figure numerals: 1. displacement sensor; 2. connecting plate; 3. piston rod; 4. end cover; 5. oil port; 6. cylinder body; 7. piston; 8. first control valve; 9. second control valve; 10. detection device; 11. high-pressure oil source. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present invention.

[0037] like Figure 1-2 As shown, a hydraulic cylinder internal leakage detection device proposed by the present invention comprises a second control valve 9, a detection device 10, a metering hydraulic cylinder, a first hydraulic pipeline, a second hydraulic pipeline, a third hydraulic pipeline and a high-pressure oil source 11 for conveying hydraulic oil;

[0038] A displacement sensor 1 for detecting the displacement of the telescopic end of the metering hydraulic cylinder is provided on the metering hydraulic cylinder, and a detection channel and a liquid filling compensation channel are provided in the metering hydraulic cylinder; wherein the detection channel and the liquid filling compensation channel are arranged in parallel; the liquid filling compensation channel is connected to a third hydraulic pipeline for connecting to the oil channel cavity of the hydraulic cylinder to be detected;

[0039] One end of the first hydraulic pipeline is connected to an oil port of the high-pressure oil source 11, the first hydraulic pipeline is communicated with the detection channel, and a first control valve 8 is provided on the first hydraulic pipeline;

[0040] One end of the second hydraulic pipeline is connected to another oil port of the high-pressure oil source 11, the second hydraulic pipeline is communicated with the liquid filling compensation channel, and a second control valve 9 is provided on the second hydraulic pipeline;

[0041] The detection device 10 is communicatively connected to the displacement sensor 1, the first control valve 8, the second control valve 9 and the high-pressure oil source 11 respectively; wherein the detection device 10 is a computer device with data receiving and processing functions.

[0042] In the present invention, when in use, the first hydraulic pipeline is connected with the high-pressure oil source 11 and the detection channel in the metering hydraulic cylinder, and then the second hydraulic pipeline is connected with the high-pressure oil source 11 and the liquid filling compensation channel in the metering hydraulic cylinder, and the third hydraulic pipeline is used to connect the liquid filling compensation channel in the metering hydraulic cylinder with the oil channel cavity of the hydraulic cylinder to be detected; the high-pressure oil source 11 supplies oil to the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be detected through the second hydraulic pipeline until the oil pressure in the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be detected from the second hydraulic pipeline is the same as the test oil pressure, and the oil pressure in the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be detected from the second hydraulic pipeline is balanced; when the first control valve 8 is opened and the second control valve 9 is closed, the displacement of the telescopic end of the metering hydraulic cylinder is detected by the displacement sensor 1 to calculate the internal leakage of the hydraulic cylinder to be detected, and the operation is simple and convenient to use.

[0043] In an optional embodiment, the metering hydraulic cylinder comprises two sets of piston rods 3, two sets of end covers 4 and a cylinder body 6; the metering hydraulic cylinder is a double-acting piston hydraulic cylinder;

[0044] A piston 7 is provided in a sealing and sliding manner in the cylinder body 6;

[0045] Two groups of oil ports 5 for connecting to the first hydraulic pipeline and the second hydraulic pipeline are respectively provided on the two groups of end covers 4, and two groups of guide sleeves are respectively provided on the two groups of end covers 4 along the central axis direction, and the two groups of end covers 4 are respectively connected to the two ends of the cylinder body 6;

[0046] The two groups of piston rods 3 respectively interfere with each other and pass through the two groups of guide sleeves to extend into the cylinder body 6, and the two groups of piston rods 3 are connected to the piston 7; wherein, the sliding part on the displacement sensor 1 is connected to any group of piston rods 3; the outer diameters of the two groups of piston rods 3 are the same, so the pressure-bearing areas on both sides of the piston 7 of the metering hydraulic cylinder are equal, and when the piston 7 is subjected to balanced force, the pressures in its left and right chambers are equal.

[0047] In an optional embodiment, a connecting plate 2 is further included; one end of the connecting plate 2 is connected to the piston rod 3 , and the other end of the connecting plate 2 is connected to a sliding member on the displacement sensor 1 .

[0048] In an optional embodiment, a seal is further included; a mounting groove is provided on the outer peripheral surface of the piston 7 along its circumferential direction; the seal is interference-fitted in the mounting groove to improve the sealing between the piston 7 and the cylinder body 6, and the seal adopts a high-pressure resistant combined seal, so the internal leakage of the metering hydraulic cylinder is zero, and the displacement of the piston 7 is strictly proportional to the volume of the hydraulic oil entering, thereby greatly improving the accuracy of the detection.

[0049] In an optional embodiment, the displacement sensor 1 is an incremental grating sensor or a magnetostrictive displacement sensor.

[0050] The present invention also proposes a detection method for a hydraulic cylinder internal leakage detection device, comprising the following specific steps:

[0051] S1. Fix the hydraulic cylinder to be tested at the stroke position where the leakage in the hydraulic cylinder is to be tested;

[0052] S2, adjusting the piston 7 of the metering hydraulic cylinder to the starting position of the metering stroke, at which time the metering stroke displayed on the detection device 10 is zero;

[0053] S3, installing the first hydraulic pipeline, the second hydraulic pipeline, the third hydraulic pipeline, the metering hydraulic cylinder, the hydraulic cylinder to be tested and the high-pressure oil source 11;

[0054] S4, close the first control valve 8, adjust the pressure of the high-pressure oil source 11 to the test pressure and keep it unchanged; open the second control valve 9, the high-pressure oil source 11 fills the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be tested with high-pressure oil, and the pressure in the oil channel cavity of the hydraulic cylinder to be tested is the same as the test pressure;

[0055] S5, after the pressure in the oil channel cavity of the hydraulic cylinder to be tested is stabilized to the test pressure, first open the first control valve 8, and then close the second control valve 9;

[0056] S6. The displacement sensor 1 detects the displacement of the piston 7 of the metering hydraulic cylinder and sends the detected displacement signal to the detection device 10; the detection device 10 analyzes and calculates the internal leakage of the hydraulic cylinder to be detected.

[0057] In an optional embodiment, the piston rod of the hydraulic cylinder to be tested in S1 is fixed by a mechanical positioning device.

[0058] In an optional embodiment, the first control valve 8 is opened 10 to 30 seconds after the pressure in the oil channel cavity of the hydraulic cylinder to be tested in S5 stabilizes to the test pressure.

[0059] It should be understood that the above specific embodiments of the present invention are only used to illustrate or explain the principles of the present invention, and do not constitute a limitation of the present invention. Therefore, any modifications, equivalent substitutions, improvements, etc. made without departing from the spirit and scope of the present invention should be included in the protection scope of the present invention. In addition, the appended claims of the present invention are intended to cover all changes and modifications that fall within the scope and boundaries of the appended claims, or the equivalent forms of such scope and boundaries.

Claims

1. A device for detecting leakage in a hydraulic cylinder, characterized in that: It comprises a second control valve (9), a detection device (10), a metering hydraulic cylinder, a first hydraulic pipeline, a second hydraulic pipeline, a third hydraulic pipeline and a high-pressure oil source (11) for conveying hydraulic oil; A displacement sensor (1) for detecting the displacement of the telescopic end of the metering hydraulic cylinder is provided on the metering hydraulic cylinder, and a detection channel and a liquid filling compensation channel are provided in the metering hydraulic cylinder; wherein the detection channel and the liquid filling compensation channel are arranged in parallel; and the liquid filling compensation channel is connected to a third hydraulic pipeline for communicating with the oil channel cavity of the hydraulic cylinder to be detected; One end of the first hydraulic pipeline is connected to an oil port of a high-pressure oil source (11), the first hydraulic pipeline is in communication with the detection channel, and a first control valve (8) is provided on the first hydraulic pipeline; One end of the second hydraulic pipeline is connected to another oil port of the high-pressure oil source (11), the second hydraulic pipeline is in communication with the liquid filling compensation channel, and a second control valve (9) is provided on the second hydraulic pipeline; The detection device (10) is communicatively connected to the displacement sensor (1), the first control valve (8), the second control valve (9) and the high-pressure oil source (11); The metering hydraulic cylinder comprises two sets of piston rods (3), two sets of end covers (4) and a cylinder body (6); A piston (7) is provided in a sealing and sliding manner in the cylinder body (6); The two sets of end covers (4) are respectively provided with two sets of oil ports (5) for connecting to the first hydraulic pipeline and the second hydraulic pipeline, and the two sets of end covers (4) are respectively provided with two sets of guide sleeves along the central axis direction, and the two sets of end covers (4) are respectively connected to the two ends of the cylinder body (6); The two groups of piston rods (3) respectively pass through the two groups of guide sleeves through interference fit and extend into the cylinder body (6), and the two groups of piston rods (3) are both connected to the piston (7); wherein the sliding member on the displacement sensor (1) is connected to any one group of piston rods (3); It also includes a connecting plate (2); one end of the connecting plate (2) is connected to the piston rod (3), and the other end of the connecting plate (2) is connected to a sliding member on a displacement sensor (1); the displacement sensor (1) is an incremental grating sensor or a magnetostrictive displacement sensor.

2. A hydraulic cylinder internal leakage detection device according to claim 1, characterized in that: It also includes a sealing member; a mounting groove is provided on the outer peripheral surface of the piston (7) along its circumferential direction; and the sealing member is sleeved in the mounting groove with an interference fit.

3. A method for detecting leakage in a hydraulic cylinder, using a device for detecting leakage in a hydraulic cylinder according to any one of claims 1 to 2, characterized in that: The specific steps include: S1. Fix the hydraulic cylinder to be tested at the stroke position where the leakage in the hydraulic cylinder is to be tested; S2, adjusting the piston (7) of the metering hydraulic cylinder to the starting position of the metering stroke, at which time the metering stroke displayed on the detection device (10) is zero; S3, installing the first hydraulic pipeline, the second hydraulic pipeline, the third hydraulic pipeline, the metering hydraulic cylinder, the hydraulic cylinder to be tested, and the high-pressure oil source (11); S4, close the first control valve (8), adjust the pressure of the high-pressure oil source (11) to the test pressure and keep it unchanged; open the second control valve (9), and the high-pressure oil source (11) fills the liquid filling compensation channel in the metering hydraulic cylinder and the oil channel cavity of the hydraulic cylinder to be tested with high-pressure oil, and the pressure in the oil channel cavity of the hydraulic cylinder to be tested is now the same as the test pressure; S5, after the pressure in the oil channel cavity of the hydraulic cylinder to be tested is stabilized at the test pressure, first open the first control valve (8), and then close the second control valve (9); S6. The displacement sensor (1) detects the displacement of the piston (7) of the metering hydraulic cylinder and sends the detected displacement signal to the detection device (10); the detection device (10) analyzes and calculates the internal leakage of the hydraulic cylinder to be detected.

4. A method for detecting leakage in a hydraulic cylinder according to claim 3, characterized in that: The piston rod of the hydraulic cylinder to be tested in S1 is fixed by a mechanical positioning device.

5. A method for detecting leakage in a hydraulic cylinder according to claim 3, characterized in that: In S5, after the pressure in the oil channel cavity of the hydraulic cylinder to be tested stabilizes to the test pressure, the first control valve (8) is opened after 10 to 30 seconds.

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