A hydraulic cylinder internal leakage detection system

Abstract

The application discloses a hydraulic cylinder internal leakage detection system, which comprises a hydraulic pump, an accumulator and a flowmeter, wherein the hydraulic pump is connected with one end of a to-be-detected hydraulic cylinder through a pipeline, the accumulator is connected with the other end of the to-be-detected hydraulic cylinder, a one-way valve is arranged on the pipeline connected with the to-be-detected hydraulic cylinder and the accumulator, the flow direction of the one-way valve is from the hydraulic cylinder to the accumulator, the accumulator is further communicated with the flowmeter through a pipeline, an electromagnetic valve is arranged on the pipeline communicated with the accumulator and the flowmeter, and the accumulator is externally connected with a pressure sensor. The accumulator collects the internal leakage amount of the hydraulic cylinder and releases the internal leakage amount in a short time, so that the average flow of the internal leakage amount is improved, the range of the flowmeter is met, the test detection of the internal leakage amount is realized, the measurement is accurate and efficient, and the automatic batch detection is suitable.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of hydraulic cylinder detection, and particularly relates to a hydraulic cylinder internal leakage detection system. BACKGROUND

[0002] The internal leakage amount of a hydraulic cylinder is an important index for measuring whether the hydraulic cylinder is qualified, and is also a necessary detection content of the hydraulic cylinder factory test and type test.

[0003] At present, the internal leakage test of the hydraulic cylinder industry is generally performed according to 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: oil is input into the working cavity of the tested hydraulic cylinder, and is pressurized to the nominal pressure, and the leakage amount leaked to the unpressurized cavity through the piston is measured. In actual application, the pressure maintaining method, the measuring cup measurement method, the sedimentation method and the like are mainly used for hydraulic cylinder internal leakage detection.

[0004] The measuring cup measurement method has low precision, and due to the small internal leakage amount, the time consumption of the measuring cup measurement is very long, which leads to very low detection efficiency. The sedimentation method is not suitable for application in the factory.

[0005] At the same time, due to the very small internal leakage amount of the hydraulic cylinder, which is much lower than the lower limit of the range of the common flowmeter, when the flowmeter is directly used for detection, the leakage amount often cannot pass through the flowmeter during the flow through the flowmeter, and therefore the common flowmeter is not suitable for detection.

[0006] The pressure maintaining method is to seal the test cavity after injecting high-pressure test medium into the test cavity, and to judge the size of the internal leakage amount of the hydraulic cylinder by measuring the pressure drop in the test cavity. This test method cannot directly reflect the internal leakage amount, and it reflects the internal leakage amount in an indirect way, and this test method is also affected by the size and specifications of the hydraulic cylinder, the internal leakage of the test table itself and the like, especially the deformation of the hydraulic cylinder body under high pressure, which leads to poor effect of the pressure maintaining method in actual application. SUMMARY

[0007] The technical problem to be solved by the present application is to provide a hydraulic cylinder internal leakage detection system which can quickly and accurately measure the internal leakage amount of the hydraulic cylinder, and is suitable for automatic control to realize automatic detection.

[0008] The technical scheme adopted by the present application is: a hydraulic cylinder internal leakage detection system, comprising a hydraulic pump, an accumulator and a flowmeter, the hydraulic pump is connected with one end of a to-be-detected hydraulic cylinder through a pipeline, the accumulator is connected with the other end of the to-be-detected hydraulic cylinder, a one-way valve is installed on the pipeline connecting the to-be-detected hydraulic cylinder and the accumulator, the flow direction of the one-way valve is from the hydraulic cylinder to the accumulator, the accumulator is also connected with the flowmeter through a pipeline, an electromagnetic valve is installed on the pipeline connecting the accumulator and the flowmeter, and the accumulator is connected with a pressure sensor.

[0009] As preferred, a throttle valve is also installed on the pipeline between the electromagnetic valve and the accumulator.

[0010] As preferred, an overflow pipeline is connected between the hydraulic pump and the to-be-detected hydraulic cylinder, and an overflow valve and a pressure gauge are connected on the overflow pipeline.

[0011] The present application has the following advantages:

[0012] (1) The accumulator is arranged to collect the internal leakage hydraulic oil of the to-be-detected hydraulic cylinder;

[0013] (2) The accumulator is arranged to collect the internal leakage hydraulic oil, and since the initial pressure of the accumulator can be adjusted, the flow rate of the released hydraulic oil can be increased, that is, the average flow of the released hydraulic oil is increased, so as to meet the measurement range of the commonly used flowmeter, and the internal leakage amount can be detected and measured;

[0014] (3) The pressure sensor is arranged to monitor the pressure before the accumulator absorbs the hydraulic oil and the pressure after the hydraulic oil is released;

[0015] (4) The electromagnetic valve is arranged to connect the accumulator and the flowmeter, and to time the release of the hydraulic oil from the accumulator;

[0016] (5) The throttle valve is arranged, and the oil discharge time of the accumulator can be adjusted by adjusting the throttle valve, so as to prevent large instantaneous flow from causing inaccurate measurement;

[0017] (6) The overflow pipeline is arranged, and the overflow valve and the pressure gauge are installed on the overflow pipeline, so as to adjust and detect the test pressure of the to-be-detected hydraulic cylinder.

[0018] The present application collects the internal leakage amount of the hydraulic cylinder by the accumulator, increases the average flow of the released internal leakage amount, so as to meet the range of the flowmeter, and thus realizes the test detection of the internal leakage amount, has the characteristics of accurate measurement and high efficiency, and is suitable for automatic batch detection. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The system schematic diagram of the present application.

[0020] In the figure: 1, hydraulic pump; 2, accumulator; 3, flowmeter; 4, check valve; 5, electromagnetic valve; 6, pressure sensor; 7, throttle valve; 8, overflow valve; 9, pressure gauge. DETAILED DESCRIPTION

[0021] The application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Embodiment 1

[0023] As shown in the figure, the hydraulic cylinder internal leakage detection system provided by the embodiment comprises a hydraulic pump 1, an accumulator 2 and a flowmeter 3. Figure 1 The hydraulic pump 1 is connected with a rodless cavity of a hydraulic cylinder to be tested through a pipeline, and an overflow pipeline is connected on the pipeline, and an overflow valve 8 and a pressure gauge 9 are installed on the overflow pipeline; the hydraulic pump 1 can inject hydraulic oil into the rodless cavity of the hydraulic cylinder to be tested, and push the piston of the hydraulic cylinder to the limit position, at this time, the pressure in the rodless cavity of the hydraulic cylinder to be tested is adjusted and controlled by adjusting the overflow valve 8 on the overflow pipeline, so that the pressure in the rodless cavity of the hydraulic cylinder to be tested rises to a specified test pressure.

[0024] The accumulator 2 is communicated with a rod cavity of the hydraulic cylinder to be tested through a pipeline, and a check valve 4 is installed on the pipeline, and the flow direction of the check valve 4 is from the hydraulic cylinder to be tested to the accumulator 2; thus, during the pressure maintaining process by the overflow valve 8, the internal leakage hydraulic oil enters the rod cavity of the hydraulic cylinder to be tested, and then flows out through the pipeline to the accumulator 2 through the check valve 4, and is collected by the accumulator 2, and when the accumulator 2 releases the internal leakage oil, the check valve can prevent the accumulator from discharging the oil into the rod cavity of the hydraulic cylinder to be tested.

[0025] The accumulator 2 is also communicated with the flowmeter 3 through a pipeline, and a throttle valve 7 and an electromagnetic valve 5 are installed on the pipeline in sequence; the throttle valve 7 is used to control the average flow of the internal leakage oil released by the accumulator 2, and the electromagnetic valve 5 is used to communicate the accumulator 2 and the flowmeter 3.

[0026] The accumulator 2 is externally connected with a pressure sensor 6; the pressure sensor 6 records the pressure at the inlet of the accumulator 2 before the internal leakage oil enters the accumulator 2, and records it as the initial pressure, and after the pressure in the accumulator 2 drops to the initial pressure after releasing the internal leakage oil, a signal is sent to disconnect the channel between the accumulator 2 and the flowmeter 3 by the electromagnetic valve 5, so as to complete the measurement of the internal leakage flow.

[0027] Embodiment 2

[0028]

[0029] ​This embodiment is basically the same as embodiment 1, except that the connection positions of hydraulic pump 1 and accumulator 2 to the hydraulic cylinder under test are changed. In this embodiment, hydraulic pump 1 is connected to the rod chamber of hydraulic cylinder under test through a pipeline, and accumulator 2 is connected to the rodless chamber of hydraulic cylinder under test through a pipeline.

[0030] Example 3

[0031] This embodiment is basically the same as embodiment 1, except that an automated control system is added. The control system includes a controller, which is connected to a pressure gauge 9, a pressure sensor 6, a flow meter 3, a hydraulic pump 1, a relief valve 8, a throttle valve 7, and a solenoid valve 5. The controller is used to control the opening and closing of the hydraulic pump 1 and the solenoid valve 5, and adjusts the relief valve 8 according to the signal received from the pressure gauge 9, so that the hydraulic cylinder under test reaches the specified test pressure and is held at the pressure. At the same time, it records the pressure before the internal leakage oil is collected at the inlet of the accumulator 2, and controls the solenoid valve 5 to open after the internal leakage oil is released from the accumulator 2 to the initial pressure.

[0032] Taking Example 1 as an example, the internal leakage detection test process of the present invention is as follows:

[0033] Start hydraulic pump 1 to introduce hydraulic oil into the rodless chamber of the hydraulic cylinder under test, and push the piston of the hydraulic cylinder to the limit position;

[0034] Adjust the overflow valve 8 to raise the pressure in the rodless chamber to the specified test pressure; at the same time, record the initial pressure P0 at the accumulator 2, and change the solenoid valve 5 from the open state to the closed state;

[0035] According to the test duration t s Maintain the pressure in the rodless chamber; during the pressure holding process of the rodless chamber of the hydraulic cylinder, after the high-pressure oil leaks into the rod chamber, it enters the accumulator 2 through the one-way valve 4, and the inlet pressure of the accumulator 2 gradually increases.

[0036] After the test time is reached, the oil supply to the rodless chamber of the hydraulic cylinder is stopped, solenoid valve 5 is energized and timing begins (the timing start point is denoted as t0), i.e., solenoid valve 5 is open, connecting accumulator 2 and flow meter 3. At the same time, the inlet pressure of accumulator 2 is monitored. When the inlet pressure of accumulator 2 drops to P0, solenoid valve 5 is de-energized and timing stops (the timing end point is denoted as t1, defined as δt=t1-t0). Flow meter 3 stops measuring, and the volume Va of the medium passing through flow meter 3 is recorded, i.e., the time from the rodless chamber to the rod chamber of the hydraulic cylinder in the specified time t. s The internal leakage volume is Va, while the instantaneous flow rate through flow meter 3 is Va / δt.

[0037] The present application is to use the characteristics of the accumulator 2 to make the collected internal leakage have a certain pressure when released, thereby improving the average flow rate of the internal leakage in unit time. When the average flow rate of the internal leakage is improved to meet the range of the flowmeter 3, it can be measured by the flowmeter 3. This detection method is less affected by external factors, and is fast, convenient, and can realize batch automatic detection.

[0038] The main principle of the present application is to collect the internal leakage of the hydraulic cylinder, make it pass through the flowmeter 3 quickly in a short time, improve the average flow rate in the measurement time, and thus meet the range of the flowmeter 3. The average flow rate improvement ratio is t s The ratio of t to δt.

[0039] In practical application, the charging pressure of the accumulator 2 should not be too high to avoid affecting the test results due to the high pressure in the rod cavity during the internal leakage test.

[0040] Table 1 is the internal leakage qualified standard in JB / T 10205:

[0041]

[0042] Table 2 is the range of a commonly used flowmeter of a domestic brand:

[0043]

[0044] From the comparison of Table 1 and Table 2, it can be seen that the internal leakage of the qualified hydraulic cylinder is far lower than the lower limit of the range of the commonly used flowmeter, which leads to the fact that the direct use of the flowmeter to measure the internal leakage of the hydraulic cylinder is not accurate.

[0045] The above is only the preferred embodiment of the present application, but the protection scope of the present application is not limited thereto. Any modification and replacement based on the technical solutions and inventive concepts provided by the present application should be covered within the protection scope of the present application.

Claims

1. A hydraulic cylinder internal leak detection system, characterized by: Including hydraulic pump (1), accumulator (2) and flowmeter (3), the hydraulic pump (1) is connected with one end of the hydraulic cylinder to be measured through pipeline, accumulator (2) is connected with the other end of the hydraulic cylinder to be measured through pipeline, and a check valve (4) is installed on the pipeline connected with the accumulator (2) of the hydraulic cylinder to be measured, the flow direction of the check valve (4) is hydraulic cylinder to accumulator (2) flow, the accumulator (2) is also communicated with the flowmeter (3) through the pipeline, and an electromagnetic valve (5) is installed on the pipeline communicated with the accumulator (2) and the flowmeter (3), the accumulator (2) is externally connected with a pressure sensor (6).

2. A hydraulic cylinder internal leak detection system as claimed in claim 1, characterized in that: A throttle valve (7) is also installed on the pipeline between the electromagnetic valve (5) and the accumulator (2).

3. A hydraulic cylinder internal leak detection system according to claim 1 or 2, characterised in that: The pipeline between the hydraulic pump (1) and the hydraulic cylinder to be measured is connected with an overflow pipeline, and an overflow valve (8) and a pressure gauge (9) are connected on the overflow pipeline.

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