Hydraulic system and testing method for hydraulic cylinder performance testing

Abstract

The present invention discloses a hydraulic system and a testing method for hydraulic cylinder performance testing, comprising a pilot circuit, a low-pressure circuit, a high-pressure circuit and a hydraulic cylinder, wherein a first two-position three-way non-leakage valve and a first hydraulically controlled one-way valve are installed between a rodless chamber of the hydraulic cylinder and a three-position four-way electromagnetic reversing valve, a second two-position three-way non-leakage valve and a second hydraulically controlled one-way valve are installed between a rod chamber and a three-position four-way electromagnetic reversing valve, a sensor assembly is installed on the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve, a low-pressure circuit has a first proportional relief valve for setting pressure, a high-pressure circuit has a second proportional relief valve for setting pressure, and a pilot circuit has a proportional pressure reducing valve for setting pressure. The present invention is used for hydraulic cylinder performance testing and describes its testing method in detail, and can automatically control the operation of the hydraulic cylinder and automatically set the overflow pressure, with a high degree of automation and accurate detection results.

Description

Technical Field

[0001] The invention relates to the field of hydraulic systems, and in particular to a hydraulic system and a testing method for hydraulic cylinder performance testing. Background Art

[0002] For any hydraulic cylinder manufacturer, every non-standard hydraulic cylinder produced must undergo factory performance testing; for standard hydraulic cylinders, sampling inspection must also be carried out to test the various performance indicators of the sampled standard hydraulic cylinders.

[0003] Most of the existing technologies use manual operation, which is time-consuming, labor-intensive, inefficient, with extremely low control accuracy and large measurement errors. What is more terrible is that manual operation has a high rate of misoperation. For example: ① For the trial operation of the hydraulic cylinder, the basic performance test of the hydraulic cylinder is tested: the operator needs to repeatedly press the button to make the hydraulic cylinder reciprocate several times throughout the stroke to completely eliminate the air inside the hydraulic cylinder. The manual operation method is time-consuming, labor-intensive and inefficient; ② For the hydraulic cylinder starting pressure characteristic test: the pressure is gradually increased by manual adjustment, and the hydraulic cylinder starting pressure characteristic test is measured. The manual control accuracy is extremely low and the pressure stability is particularly poor; ③ For the hydraulic cylinder pressure resistance test: the piston cylinder of the tested hydraulic cylinder is fully extended to the limit stroke position, and the overflow valve handle is manually controlled to pressurize to N times the rated working pressure (Note: the test pressure multiple can be executed according to requirements), and the specified pressure holding time is reached. Observe the appearance of the hydraulic cylinder for oil leakage or deformation. The pressure stability of manual control is particularly poor. Moreover, the pressure value of N times the rated working pressure , it is difficult to achieve accurate values ​​manually; ④ Leakage test in hydraulic cylinder: let the working chamber (large chamber or small chamber) of the tested hydraulic cylinder pass pressurized oil, pressurize it to the rated pressure or the pressure specified by the customer, and judge whether the leakage performance in the hydraulic cylinder is feasible by measuring the pressure drop of the pressure maintenance. Similarly, the pressure stability of manual control is extremely low, and it is difficult to adjust the rated working pressure or the pressure value specified by the customer to the precise value manually; ⑤ Leakage test of hydraulic cylinder: while conducting trial operation, starting pressure, pressure resistance and internal leakage test, check whether there is leakage at the piston rod seal, various static seals of the cylinder body, joint surfaces and adjustable mechanisms. It is difficult to make consistent judgments by observing with the naked eye; ⑥ Stroke detection test of hydraulic cylinder: let the piston of the tested cylinder stay at the extreme positions at both ends of the stroke, and manually detect its stroke; the manual measurement error is large. Summary of the invention

[0004] The main technical problem solved by the present invention is to provide a hydraulic system and a testing method for hydraulic cylinder performance testing, which can automatically control the operation of the hydraulic cylinder and set the overflow pressure, have a high degree of automation and accurate test results.

[0005] In order to solve the above technical problems, a technical solution adopted by the present invention is: a hydraulic system for hydraulic cylinder performance testing is provided, including a pilot circuit, a low-pressure circuit, a high-pressure circuit and a hydraulic cylinder, the pilot circuit and the low-pressure circuit are connected to the hydraulic cylinder through a three-position four-way electromagnetic reversing valve, and oil is supplied to the rod chamber or the rodless chamber of the hydraulic cylinder through the three-position four-way electromagnetic reversing valve, the high-pressure circuit is connected to the rod chamber and the rodless chamber of the hydraulic cylinder, a first two-position three-way non-leakage valve and a first hydraulically controlled one-way valve are sequentially installed between the rodless chamber of the hydraulic cylinder and the three-position four-way electromagnetic reversing valve, a second two-position three-way non-leakage valve and a second hydraulically controlled one-way valve are sequentially installed between the rod chamber and the three-position four-way electromagnetic reversing valve, a sensor assembly for detecting the hydraulic cylinder pressure is installed on the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve, the low-pressure circuit has a first proportional overflow valve for setting the pressure, the high-pressure circuit has a second proportional overflow valve for setting the pressure, and the pilot circuit has a proportional pressure reducing valve for setting the pressure.

[0006] In a preferred embodiment of the present invention, the first hydraulically controlled one-way valve and the second hydraulically controlled one-way valve are respectively connected to the first two-position four-way solenoid reversing valve and the second two-position four-way solenoid reversing valve, and are controlled to be on and off by the first two-position four-way solenoid reversing valve and the second two-position four-way solenoid reversing valve.

[0007] In a preferred embodiment of the present invention, the sensor assembly includes a low-pressure pressure sensor and a high-pressure pressure sensor, and the low-pressure pressure sensor and the high-pressure pressure sensor are switched through corresponding two-position three-way non-leakage valves to detect the hydraulic cylinder.

[0008] In a preferred embodiment of the present invention, the pilot circuit includes a low-pressure, small-flow motor pump group connected to the oil tank, and the low-pressure, small-flow motor pump group is connected to the three-position, four-way solenoid reversing valve through a proportional pressure reducing valve, and provides pilot oil for unlocking the three-position, four-way solenoid reversing valve and the oil-controlled one-way valve, the pilot reversing oil supply of the reversing valve, and the starting pressure of the test hydraulic cylinder; the low-pressure circuit includes a low-pressure, large-flow motor pump group, and the low-pressure, large-flow motor pump group is connected to the three-position, four-way solenoid reversing valve through a proportional speed control valve, and the high-pressure circuit includes a high-pressure, small-flow motor pump group, and the high-pressure, small-flow motor pump group is connected to the rodless chamber of the hydraulic cylinder through the third two-position, three-way non-leakage valve and the third hydraulically controlled one-way valve in turn, and is connected to the rod chamber of the hydraulic cylinder through the fourth two-position, three-way non-leakage valve and the fourth hydraulically controlled one-way valve.

[0009] In a preferred embodiment of the present invention, a first one-way valve and a first low-pressure filter are connected in sequence between the low-pressure and small-flow motor pump group and the proportional pressure reducing valve, and a fourth one-way valve is connected between the proportional pressure reducing valve and the three-position four-way electromagnetic reversing valve.

[0010] In a preferred embodiment of the present invention, a second low-pressure filter, a proportional speed control valve and a second one-way valve are connected in sequence between the low-pressure and high-flow motor pump group and the three-position four-way electromagnetic reversing valve; one end of the first proportional overflow valve is connected between the proportional speed control valve and the second low-pressure filter, and the other end is connected to the oil tank.

[0011] In a preferred embodiment of the present invention, the third hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve are respectively connected to the third two-position four-way solenoid reversing valve and the third two-position four-way solenoid reversing valve, and are controlled on and off by the third two-position four-way solenoid reversing valve and the fourth two-position four-way solenoid reversing valve.

[0012] In a preferred embodiment of the present invention, a throttling damping and a third one-way valve are connected between the third two-position three-way non-leakage valve and the fourth two-position three-way non-leakage valve and the high-pressure and small-flow motor pump group, and one end of the second proportional relief valve is connected between the high-pressure and small-flow motor pump group and the third one-way valve, and the other end is connected to the oil tank.

[0013] In a preferred embodiment of the present invention, the hydraulic oil in the oil tank is hydraulic oil containing fluorescent agent, and a purple light flashlight is used to illuminate the hydraulic cylinder to determine the leakage condition of the hydraulic cylinder. An infrared displacement sensor for detecting the stroke of the hydraulic cylinder is installed on the hydraulic cylinder, and the hydraulic system is controlled by PLC.

[0014] In order to solve the above technical problems, another technical solution adopted by the present invention is: to provide a testing method of a hydraulic system for testing the performance of a hydraulic cylinder, comprising the following steps:

[0015] a. The low-pressure and low-flow motor pump group starts, the pilot circuit establishes the set pressure, the potentiometer of the first proportional relief valve returns to zero, the low-pressure and high-flow motor pump group starts at zero pressure, the first proportional relief valve adjusts the pressure to the set value, the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve are energized to connect the corresponding low-pressure pressure sensor with the rod chamber and rodless chamber of the hydraulic cylinder, the three-position four-way solenoid reversing valve is connected to the right position to allow the hydraulic oil of the low-pressure and high-flow motor pump group to enter the rodless chamber of the hydraulic cylinder, and the pilot oil opens between the rod chamber and the three-position four-way solenoid reversing valve. The hydraulically controlled one-way valve, that is: the second two-position four-way solenoid reversing valve unlocks the second hydraulically controlled one-way valve, so that the oil in the rod chamber flows back to the oil tank, and the hydraulic cylinder extends to the limit position; the first two-position four-way solenoid reversing valve unlocks the first hydraulically controlled one-way valve, and the three-position four-way solenoid reversing valve changes to the left position, and the hydraulic oil of the low-pressure and large-flow motor pump group enters the rod chamber of the hydraulic cylinder, and the hydraulic oil in the rodless chamber flows back to the oil tank until the hydraulic cylinder retracts to the limit position. Repeat this process for many times, observe the condition of the hydraulic cylinder, and finally release the pressure in the rod chamber and the rodless chamber of the hydraulic cylinder, and all components stop working;

[0016] b. The potentiometer corresponding to the proportional pressure reducing valve is reset to zero, the low-pressure and low-flow motor pump group is started, and the set pilot circuit pressure is established. The first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve are energized to connect the corresponding low-pressure pressure sensor with the rod chamber and rodless chamber of the hydraulic cylinder. The three-position four-way solenoid reversing valve is connected to the right position to allow the oil of the low-pressure and low-flow motor pump group to enter the rodless chamber of the hydraulic cylinder. At the same time, the second two-position four-way solenoid reversing valve unlocks the second hydraulic control check valve, and the oil in the rod chamber flows back to the oil tank. The potentiometer corresponding to the proportional pressure reducing valve is adjusted to make the pressure rise slowly. The deferred sensor detects the pressure in real time to obtain the instantaneous maximum pressure. After the test is completed, the hydraulic cylinder retracts according to the steps in step a. Finally, the rod chamber and rodless chamber of the hydraulic cylinder are depressurized, and all components stop working;

[0017] c. The low-pressure and low-flow motor pump group starts, the pilot circuit establishes the set pressure, the potentiometer of the first proportional relief valve returns to zero, the low-pressure and high-flow motor pump group is started at zero pressure, the first proportional relief valve adjusts the pressure to the set value, the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve lose power to connect the corresponding high-pressure pressure sensor with the rod chamber and the rodless chamber of the hydraulic cylinder. After the hydraulic cylinder is extended to the limit position in step a, the low-pressure and high-flow motor pump group stops, and then the high-pressure and low-flow motor pump group starts, and the pressure of the second proportional relief valve is adjusted to make the pressure oil of the high-pressure and low-flow motor pump group enter the rodless chamber of the hydraulic cylinder. The hydraulic control check valve between the rod chamber and the two-position three-way electromagnetic reversing valve in the high-pressure circuit is opened by the pilot oil, and the hydraulic oil in the rod chamber flows back to the oil tank. After the high-pressure pressure time, the potentiometer of the second proportional relief valve returns to zero, and the high-pressure and low-flow motor pump is unloaded. At this time, the rodless chamber of the hydraulic cylinder enters the pressure holding time. After the pressure holding time, the pressure drop of the corresponding chamber of the hydraulic cylinder is observed.

[0018] d. The low-pressure and low-flow motor pump group starts, the pilot circuit establishes the set pressure, the potentiometer of the first proportional relief valve returns to zero, the low-pressure and high-flow motor pump group is started at zero pressure, the first proportional relief valve adjusts the pressure to the set value, the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve lose power to connect the corresponding high-pressure pressure sensor with the rod chamber and the rodless chamber of the hydraulic cylinder. After the hydraulic cylinder retracts to the limit position in step a, the low-pressure and high-flow motor pump group stops, and then the high-pressure and low-flow motor pump group starts, and the pressure of the second proportional relief valve is adjusted to allow the pressure oil of the high-pressure and low-flow motor pump group to enter the rod chamber of the hydraulic cylinder. The hydraulic control check valve between the rodless chamber and the two-position three-way electromagnetic reversing valve in the high-pressure circuit is opened by the pilot oil, and the hydraulic oil in the rodless chamber flows back to the oil tank. After the high-pressure pressure time, the potentiometer of the second proportional relief valve returns to zero, and the high-pressure and low-flow motor pump is unloaded. At this time, the rod chamber of the hydraulic cylinder enters the pressure holding time. After the pressure holding time, the pressure drop of the corresponding chamber of the hydraulic cylinder is observed.

[0019] The beneficial effects of the present invention are as follows: the hydraulic system and the testing method for the hydraulic cylinder performance test of the present invention can automatically control the operation of the hydraulic cylinder and can set the overflow pressure, with a high degree of automation and accurate testing results. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0021] Figure 1 It is a hydraulic principle schematic diagram of a preferred embodiment of a hydraulic system for testing the performance of a hydraulic cylinder according to the present invention;

[0022] The markings of the components in the accompanying drawings are as follows: 1. Low-pressure circuit, 101. Low-pressure and large-flow motor pump group, 102. Second low-pressure filter, 103. Proportional speed control valve, 104. Second one-way valve, 105. First proportional relief valve, 106. Three-position four-way solenoid reversing valve, 1071. First hydraulically controlled one-way valve, 1072. Second hydraulically controlled one-way valve, 1081. First two-position three-way non-leakage valve, 1082. Second two-position three-way non-leakage valve, 109. Hydraulic cylinder, 110. Purple light flashlight, 111. Infrared displacement sensor, 2. High-pressure circuit, 201. High-pressure and small-flow motor pump group, 202. Third one-way valve, 1083. Third three-way non-leakage valve, 1084. Fourth three-way non-leakage valve, 2051. Third hydraulically controlled one-way valve, 2052, the fourth hydraulically controlled one-way valve, 204, throttling damping, 3063, the third two-position four-way solenoid reversing valve, 3064, the fourth two-position four-way solenoid reversing valve, 3, pilot circuit, 301, low-pressure and small-flow motor pump group, 3021, the first one-way valve, 303, the first low-pressure filter, 304, the proportional pressure reducing valve, 305, the overflow valve, 3022, the fourth one-way valve, 3061, the first two-position four-way solenoid reversing valve, 3062, the second two-position four-way solenoid reversing valve, 4, the oil tank. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] See also Figure 1A hydraulic system for testing the performance of a hydraulic cylinder comprises a pilot circuit 3, a low-pressure circuit 1, a high-pressure circuit 2 and a hydraulic cylinder 109. The pilot circuit 3 and the low-pressure circuit 1 are connected to the hydraulic cylinder 109 through a three-position four-way electromagnetic reversing valve 106. The three-position four-way electromagnetic reversing valve 106 supplies oil to the rod chamber or the rodless chamber of the hydraulic cylinder 109. The high-pressure circuit 2 is connected to the rod chamber and the rodless chamber of the hydraulic cylinder 109. A first two-position three-way non-leakage valve 1081 and a first two-position three-way non-leakage valve 1082 are sequentially installed between the rodless chamber of the hydraulic cylinder 109 and the three-position four-way electromagnetic reversing valve 106. The hydraulically controlled one-way valve 1071 has a second two-position three-way non-leakage valve 1082 and a second hydraulically controlled one-way valve 1072 installed in sequence between the rod chamber and the three-position four-way solenoid reversing valve 106. The first two-position three-way non-leakage valve 1081 and the second two-position three-way non-leakage valve 1082 are installed with a sensor assembly for detecting the pressure of the hydraulic cylinder 109. The low-pressure circuit 1 has a first proportional relief valve 105 for setting the pressure, the high-pressure circuit 2 has a second proportional relief valve 205 for setting the pressure, and the pilot circuit 3 has a proportional pressure reducing valve 304 for setting the pressure.

[0025] In addition, the first hydraulically controlled one-way valve 1071 and the second hydraulically controlled one-way valve 1072 are connected to the first two-position four-way electromagnetic reversing valve 3061 and the second two-position four-way electromagnetic reversing valve 3062 respectively, and are controlled to be on and off by the first two-position four-way electromagnetic reversing valve 3061 and the second two-position four-way electromagnetic reversing valve 3062.

[0026] In addition, the sensor assembly includes a low-pressure pressure sensor PACL / PCBL and a high-pressure pressure sensor PCAH / PCBH, which are switched through corresponding two-position three-way non-leakage valves to detect the hydraulic cylinder. The detection pressure range of the low-pressure pressure sensor PACL / PCBL is 0-6Mpa, and the detection pressure range of the high-pressure pressure sensor PCAH / PCBH is 0-60Mpa.

[0027] In addition, the pilot circuit 3 includes a low-pressure, low-flow motor pump group 301 connected to the oil tank 4. The low-pressure, low-flow motor pump group 301 is connected to the three-position, four-way solenoid reversing valve 106 through a proportional pressure reducing valve 304. A first one-way valve 3021 and a first low-pressure filter 303 are connected in sequence between the low-pressure, low-flow motor pump group 301 and the proportional pressure reducing valve 304. A fourth one-way valve 3022 is connected between the proportional pressure reducing valve 304 and the three-position, four-way solenoid reversing valve 106.

[0028] The low-pressure circuit 1 includes a low-pressure, high-flow motor pump group 101, and a second low-pressure filter 102, a proportional speed control valve 103 and a second one-way valve 104 are connected in sequence between the low-pressure, high-flow motor pump group 101 and a three-position, four-way electromagnetic reversing valve 106. One end of the first proportional overflow valve 105 is connected between the proportional speed control valve 103 and the second low-pressure filter 102, and the other end is connected to the oil tank 4.

[0029] The high-pressure circuit 2 includes a high-pressure, low-flow motor pump group 201, which is connected to the rodless chamber of the hydraulic cylinder 109 through the third two-position, three-way, non-leakage valve 1083 and the third hydraulically controlled one-way valve 2051 in sequence, and is connected to the rod chamber of the hydraulic cylinder 109 through the fourth two-position, three-way, non-leakage valve 1084 and the fourth hydraulically controlled one-way valve 2052.

[0030] In addition, the third hydraulically controlled one-way valve 2051 and the fourth hydraulically controlled one-way valve 2052 are connected to the third two-position four-way solenoid reversing valve 1083 and the third two-position four-way solenoid reversing valve 1084 respectively, and are controlled to be on and off by the third two-position four-way solenoid reversing valve 1083 and the fourth two-position four-way solenoid reversing valve 1084.

[0031] In addition, a throttling damper 204 and a third one-way valve 202 are connected between the third two-position three-way non-leakage valve 1083 and the fourth two-position three-way non-leakage valve 1084 and the high-pressure and small-flow motor pump group 201, and one end of the second proportional relief valve 203 is connected between the high-pressure and small-flow motor pump group 201 and the third one-way valve 202, and the other end is connected to the oil tank 4.

[0032] In addition, the hydraulic oil in the oil tank 1 contains fluorescent agent and is illuminated by a purple light flashlight 110 to determine the leakage condition of the hydraulic cylinder 109 . An infrared displacement sensor 111 for detecting the stroke of the hydraulic cylinder 109 is installed on the hydraulic cylinder 109 .

[0033] Test the hydraulic cylinder and test its basic performance:

[0034] The low-pressure, low-flow motor pump group 301 starts to establish the previously set 10Mpa pilot circuit 3 pressure; the potentiometer corresponding to the electromagnet YVP1 of the first proportional relief valve 105 is reset to zero, and the low-pressure, high-current motor pump group 101 is started at zero pressure. The PLC automatically controls the potentiometer corresponding to YVP1 to adjust the pressure value of the first proportional relief valve 105 to 5Mpa. At the same time, because the hydraulic cylinder is in low-pressure reciprocating motion, the first two-position three-way non-leakage valve 1081 and the second two-position three-way non-leakage valve 1082 are energized, so that the two low-pressure pressure sensors PCAL and PCBL are connected to the rod chamber and rodless chamber of the hydraulic cylinder 1096 respectively. The electromagnet of the second two-position three-way solenoid reversing valve 3062 is energized, so that the second hydraulically controlled one-way valve 1072 is unlocked, and the three-position four-way solenoid reversing valve 106 is switched to the right position. The low-pressure and large-flow hydraulic oil of the low-pressure and large-flow motor pump group 301 flows to the rodless chamber of the hydraulic cylinder 109 through the second low-pressure filter 102, the proportional speed regulating valve 103, the second one-way valve 104, the three-position four-way solenoid reversing valve 106 and the first hydraulically controlled one-way valve 1071 respectively, and the hydraulic oil in the rod chamber returns to the oil tank 4 through the second hydraulically controlled one-way valve 1072 and the three-position four-way solenoid reversing valve 106. The proportional speed regulating valve 103 can change the flow rate by adjusting the potentiometer corresponding to its proportional solenoid YVP4 to ensure that the tested hydraulic cylinder can run smoothly at a reasonable speed; when the hydraulic cylinder activity is pushed to the head, the pressure of the low-pressure pressure sensor PCAL will rise to about 5Mpa. At this time, the pressure signal is fed back to the PLC, and the PLC will make the electromagnets YVb and YV2 successively The power is lost, and then the electromagnet YV1 is energized to unlock the first hydraulically controlled one-way valve 1071, and YVa is energized to switch the three-position four-way electromagnetic reversing valve 106 to the left position. The low-pressure and high-flow hydraulic oil of the low-pressure and high-flow motor pump group 101 passes through the second low-pressure filter 102, the proportional speed regulating valve 103, the second one-way valve 104, the three-position four-way electromagnetic reversing valve 106 and the second hydraulically controlled one-way valve 1072 to the rod chamber of the hydraulic cylinder 109. At the same time, the hydraulic cylinder 109 The oil in the rodless chamber is returned to the oil tank 4 through the first hydraulically controlled one-way valve 1071 and the three-position four-way electromagnetic reversing valve 106; when the piston of the hydraulic cylinder 109 is retracted to the bottom, the pressure of the low-pressure pressure sensor PCBL will rise to about 5Mpa, and the pressure signal will be fed back to the PLC. The PLC repeatedly controls the on and off of the corresponding electromagnetic valves above, thereby controlling the hydraulic cylinder to complete the set n reciprocating motions (the number of reciprocating motions of the hydraulic cylinder n can be manually opened and set), and completely eliminating the air inside the hydraulic cylinder. During this test, observe the operating status of the hydraulic cylinder to determine whether the hydraulic cylinder has abnormal phenomena such as long-term creeping; after the determination is completed, install the above retraction method to retract the hydraulic cylinder, and energize the electromagnets YV1 and YV2 to relieve the pressure of the rodless chamber and the rod chamber of the tested hydraulic cylinder 109. Finally, all electromagnets automatically lose power, all potentiometers automatically return to zero, and the hydraulic pumps automatically stop working.

[0035] Test on hydraulic cylinder starting pressure characteristics:

[0036] The potentiometer corresponding to the proportional solenoid YVP3 of the proportional pressure reducing valve 304 is reset to zero, and then the low-pressure small-flow motor pump group 301 is started to establish the previously set 10Mpa pilot circuit pressure; because the starting pressure of the test hydraulic cylinder 109 is low pressure, the solenoid YV7 of the first two-position three-way non-leakage valve 1081 and the solenoid YV8 of the second two-position three-way non-leakage valve 1082 are energized, so that the low-pressure pressure sensor PCAL and PCBL are connected to the rodless chamber and the rod chamber of the tested hydraulic cylinder 109 respectively; the solenoid YV2 is energized to connect the second hydraulic control The one-way valve 1072 is unlocked, and then YVb is energized, so that the three-position four-way electromagnetic reversing valve 106 is switched to the right position, and the low-pressure pressure oil of the low-pressure small-flow motor pump group 301 passes through the first one-way valve 3021, the first low-pressure filter 303, the proportional pressure reducing valve 304, the fourth one-way valve 3022, the three-position four-way electromagnetic reversing valve 106, and the first hydraulic one-way valve 1071 to the rodless chamber of the hydraulic cylinder 109. At the same time, the rod chamber oil of the hydraulic cylinder 109 flows back to the oil tank 4 through the second hydraulic one-way valve 1072 and the three-position four-way electromagnetic reversing valve 106; the PLC automatically and slowly adjusts the proportional solenoid YVP3 corresponding potentiometer of the proportional pressure reducing valve 304 to slowly increase the pressure. At the same time, the low-pressure pressure sensor PCAL feeds back the measured pressure to the PLC in real time. When the pressure is slowly rising, the pressure suddenly drops, and the instantaneous highest point pressure is captured by the PLC. The highest pressure value at this point is: the starting pressure of the hydraulic cylinder 109. After the measurement is completed, the hydraulic cylinder under test is retracted according to the steps of "trial run of the hydraulic cylinder and test of the basic performance of the hydraulic cylinder", and the electromagnets YV1 and YV2 are energized to relieve the pressure in the rodless chamber and the rod chamber of the hydraulic cylinder under test 109. Finally, all electromagnets automatically lose power, all potentiometers automatically return to zero, and the hydraulic pumps automatically stop working.

[0037] Hydraulic cylinder pressure test, hydraulic cylinder internal leakage test, hydraulic cylinder external leakage test and hydraulic cylinder stroke detection test:

[0038] The low-pressure and high-flow motor pump group 101 is started to establish the previously set 10Mpa pilot circuit pressure; the potentiometer corresponding to the proportional solenoid YVP1 of the first proportional relief valve 105 is reset to zero, and the low-pressure and low-flow pump group 301 is started at zero pressure. The PLC automatically controls the potentiometer corresponding to YVP1 to automatically adjust the pressure value of the first proportional relief valve 105 to 5Mpa. Because the pressure test of the hydraulic cylinder 109 is a high-pressure test, the electromagnets YV7 and YV8 must be de-energized to block the connection between the low-pressure pressure sensors PCAL and PCBL and the rodless chamber and the rod chamber of the tested hydraulic cylinder 109, that is, the pressure measurement is performed by the high-pressure pressure sensor PCA which is connected to the rodless chamber and the rod chamber. H and PCBH are detected and fed back to PLC; electromagnet YV2 is energized to unlock the second hydraulically controlled one-way valve 1072, and YVb is energized to change the three-position four-way electromagnetic reversing valve 106 to the right position. The low-pressure and high-flow hydraulic oil of the low-pressure and high-flow motor pump group 101 passes through the second low-pressure filter 102, the proportional speed regulating valve 103, the second one-way valve 104, the three-position four-way electromagnetic reversing valve 106, and the first hydraulically controlled one-way valve 1071 to the rodless chamber of the hydraulic cylinder 109. At the same time, the oil in the rod chamber of the hydraulic cylinder 109 passes through the second hydraulically controlled one-way valve 1072 and the three-position four-way electromagnetic reversing valve 106 to return to the oil tank 4. The large flow and low pressure make the tested hydraulic cylinder extend quickly. ④When the piston of the hydraulic cylinder is pushed to the top, the pressure of the high-pressure pressure sensor PCAH will rise to about 5Mpa. At this time, the pressure signal will be fed back to the PLC, and the PLC will make the electromagnets YVb and YV2 lose power successively and shut down the low-pressure large flow motor pump group; the high-pressure small flow motor pump group 201 will start, and the PLC will automatically adjust the corresponding potentiometer of the proportional electromagnet YVP2 of the second proportional relief valve 203 to make the pressure reach 1.5 times the rated pressure (the pressure can be opened and set manually, and it is temporarily set here 50Mpa), the electromagnet YV4 is energized to unlock the fourth hydraulically controlled one-way valve 2052, and then the electromagnet YV5 is energized to allow the high-pressure and low-flow pressure oil 201 to pass through the third one-way valve 202, the third two-position three-way non-leakage valve 1083, and the third hydraulically controlled one-way valve 2051 to the rodless chamber of the hydraulic cylinder 109. At the same time, the rod chamber of the hydraulic cylinder 109 is connected to the oil tank 4 through the fourth hydraulically controlled one-way valve 2052, the fourth two-position three-way non-leakage valve 1084, and the throttling damping 204.After the high-pressure pressing time T1 (time T1 can be set manually), the corresponding potentiometer of the proportional solenoid YVP2 of the second proportional relief valve 203 automatically returns to zero, and the high-pressure small-flow motor pump group 201 is unloaded. At this moment, the rodless chamber enters the pressure holding time T2 (time T2 can be set manually). During this period of time T2, the high-pressure pressure sensor PCAH will feed back the pressure signal to the PLC in real time. After the T2 time is over; observe with the naked eye whether the hydraulic cylinder under test is deformed; determine whether the pressure resistance of the hydraulic cylinder under test is qualified; use a purple flashlight to illuminate various parts of the hydraulic cylinder under test to seep out fluorescent hydraulic oil; determine whether the external leakage of the hydraulic cylinder under test meets the standard; PLC will automatically obtain the pressure drop difference after the T2 time is over, which can determine whether the internal leakage of the hydraulic cylinder under test meets the requirements; at the same time, the actual stroke of the hydraulic cylinder under test can be accurately measured by the infrared displacement sensor to determine whether it meets the requirements of the drawing.

[0039] Measure the pressure resistance test of the rod chamber of the hydraulic cylinder. The specific test method is as follows:

[0040] The low-pressure and low-flow motor pump group 301 is started to establish the previously set 10Mpa pilot circuit pressure; the potentiometer corresponding to the proportional solenoid YVP1 of the first proportional relief valve 105 is reset to zero, and the low-pressure and high-flow motor pump group 101 is started at zero pressure. The PLC automatically controls the potentiometer corresponding to YVP1 to automatically adjust the pressure value of the first proportional relief valve 105 to 5Mpa. Because the pressure test of the hydraulic cylinder 109 is a high-pressure test, the electromagnets YV7 and YV8 must be de-energized to block the connection between the low-pressure pressure sensors PCAL and PCBL and the rodless chamber and the rod chamber of the hydraulic cylinder 109 under test, that is, the pressure measurement is performed by the high-pressure pressure sensor connected to the rodless chamber and the rod chamber. PCAH and PCBH are tested and fed back to PLC; electromagnet YV1 is energized to unlock the first hydraulically controlled one-way valve 1071, and YVa is energized to switch the three-position four-way electromagnetic reversing valve 106 to the left position. The hydraulic oil of the low-pressure and large-flow motor pump group 101 passes through the second low-pressure filter 102, the proportional speed control valve 103, the second one-way valve 104, the three-position four-way reversing electromagnetic valve 106, and the second hydraulically controlled one-way valve 1072 to the rod chamber of the hydraulic cylinder 109. At the same time, the oil in the rodless chamber of the hydraulic cylinder 109 passes through the first hydraulically controlled one-way valve 1071 and the three-position four-way reversing electromagnetic valve 106 to return to the oil tank 4. The large flow and low pressure make the tested hydraulic cylinder retract quickly. ④ When the piston of the hydraulic cylinder retracts to the head, the pressure of the high-pressure pressure sensor PCBH will rise to about 5Mpa. At this time, the pressure signal will be fed back to the PLC, and the PLC will successively de-energize the electromagnets YVa and YV1 and shut down the low-pressure and high-flow motor pump group 101; the high-pressure and low-flow motor pump group 201 will start, and the PLC will automatically adjust the corresponding potentiometer of the proportional electromagnet YVP2 of the second proportional relief valve 203 to make the pressure reach 1.5 times the rated pressure (the pressure can be set manually, and it is temporarily set to 5 here). 0Mpa), the electromagnet YV3 is energized to unlock the third hydraulically controlled one-way valve 2051, and then the electromagnet YV6 is energized to make the pressure oil of the high-pressure and small-flow motor pump group 201 pass through the third one-way valve 202, the fourth two-position three-way non-leakage valve 1084, and the fourth hydraulically controlled one-way valve 2052 to the rod chamber of the hydraulic cylinder 109. At the same time, the rodless chamber of the hydraulic cylinder 109 is connected to the oil tank 4 through the third hydraulically controlled one-way valve 2051, the fourth two-position three-way non-leakage valve 1083, and the throttling damping 204.After the high-pressure pressing time T1 (time T1 can be set manually), the corresponding potentiometer of the proportional electromagnet YVP2 of the second proportional relief valve 105 automatically returns to zero, and the high-pressure small-flow motor pump group is unloaded. At this moment, the rod chamber enters the pressure holding time T2 (time T2 can be set manually). During the period of T2, the high-pressure pressure sensor PCBH will feed back the pressure signal to the PLC in real time. After the T2 time is over, the PLC will automatically obtain the pressure drop difference, and can determine whether the leakage in the rod chamber of the hydraulic cylinder under test meets the requirements. After all the test measurements are completed, the hydraulic cylinder under test is retracted according to the steps of "trial run of the hydraulic cylinder, test of the basic performance of the hydraulic cylinder", and the electromagnets YV1 and YV2 are energized to relieve the pressure in the rodless chamber and the rod chamber of the hydraulic cylinder under test. Finally, all electromagnets automatically lose power, all potentiometers automatically return to zero, and the hydraulic pumps automatically stop working.

[0041] Different from the prior art, the hydraulic system and testing method for hydraulic cylinder performance testing of the present invention can automatically control the operation of the hydraulic cylinder and set the overflow pressure, with a high degree of automation and accurate testing results.

[0042] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A hydraulic system for testing the performance of a hydraulic cylinder, characterized in that: The control valve is used to control the pressure of the hydraulic cylinder to control the pressure of the hydraulic cylinder, and the control valve is used to control the pressure of the hydraulic cylinder ... The low-pressure circuit has a first proportional relief valve for setting pressure, the high-pressure circuit has a second proportional relief valve for setting pressure, the pilot circuit has a proportional pressure reducing valve for setting pressure, the pilot circuit includes a low-pressure, small-flow motor pump group connected to the oil tank, the low-pressure, small-flow motor pump group is connected to the three-position four-way electromagnetic reversing valve through the proportional pressure reducing valve, the low-pressure circuit includes a low-pressure, large-flow motor pump group, the low-pressure, large-flow motor pump group is connected to the three-position four-way electromagnetic reversing valve through the proportional speed regulating valve; the high-pressure circuit includes a high-pressure, small-flow motor pump group, the high-pressure, small-flow motor pump group is connected to the rodless chamber of the hydraulic cylinder through the third two-position three-way non-leakage valve and the third hydraulically controlled one-way valve in turn, and is connected to the rod chamber of the hydraulic cylinder through the fourth two-position three-way non-leakage valve and the fourth hydraulically controlled one-way valve, The first hydraulically controlled one-way valve and the second hydraulically controlled one-way valve are respectively connected to the first two-position four-way solenoid reversing valve and the second two-position four-way solenoid reversing valve, and are controlled on and off by the first two-position four-way solenoid reversing valve and the second two-position four-way solenoid reversing valve. The sensor assembly includes a low-pressure pressure sensor and a high-pressure pressure sensor, and the low-pressure pressure sensor and the high-pressure pressure sensor are switched by corresponding two two-position three-way non-leakage valves to detect the hydraulic cylinder. The second low-pressure filter, the proportional speed control valve and the second one-way valve are connected in sequence between the low-pressure large-flow motor pump group and the three-position four-way solenoid reversing valve. One end of the first proportional overflow valve is connected between the proportional speed control valve and the second low-pressure filter, and the other end is connected to the oil tank. The third hydraulically controlled one-way valve and the fourth hydraulically controlled one-way valve are respectively connected to the third two-position four-way solenoid reversing valve and the third two-position four-way solenoid reversing valve, and are controlled on and off by the third two-position four-way solenoid reversing valve and the fourth two-position four-way solenoid reversing valve.

2. The hydraulic system for hydraulic cylinder performance testing according to claim 1, characterized in that: A first one-way valve and a first low-pressure filter are connected in sequence between the low-pressure and small-flow motor pump group and the proportional pressure reducing valve, and a fourth one-way valve is connected between the proportional pressure reducing valve and the three-position four-way electromagnetic reversing valve.

3. The hydraulic system for hydraulic cylinder performance testing according to claim 1, characterized in that: A throttling damping and a third one-way valve are connected between the third two-position three-way non-leakage valve and the fourth two-position three-way non-leakage valve and the high-pressure and small-flow motor pump group; one end of the second proportional relief valve is connected between the high-pressure and small-flow motor pump group and the third one-way valve, and the other end is connected to the oil tank.

4. The hydraulic system for hydraulic cylinder performance testing according to claim 3, characterized in that: The hydraulic oil in the oil tank contains fluorescent agent and is illuminated by a purple flashlight to determine the leakage of the hydraulic cylinder. An infrared displacement sensor for detecting the stroke of the hydraulic cylinder is installed on the hydraulic cylinder, and the hydraulic system is controlled by PLC.

5. A method for testing a hydraulic system for testing the performance of a hydraulic cylinder as claimed in claim 1, characterized in that: The following steps are involved: a. The low-pressure and low-flow motor pump group starts, the pilot circuit establishes the set pressure, the potentiometer of the first proportional relief valve returns to zero, the low-pressure and high-flow motor pump group starts at zero pressure, the first proportional relief valve adjusts the pressure to the set value, the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve are energized to connect the corresponding low-pressure pressure sensor with the rod chamber and the rodless chamber of the hydraulic cylinder, and the pilot oil opens the hydraulically controlled one-way valve between the rod chamber and the three-position four-way solenoid reversing valve, the second two-position four-way solenoid reversing valve unlocks the second hydraulically controlled one-way valve, and the three-position four-way solenoid reversing valve is opened. The directional valve is switched to the right position, so that the hydraulic oil of the low-pressure and high-flow motor pump group enters the rodless chamber of the hydraulic cylinder, and the oil in the rod chamber flows back to the oil tank, so that the hydraulic cylinder extends to the limit position; the first two-position four-way solenoid reversing valve unlocks the first hydraulic-controlled one-way valve, and the three-position four-way solenoid reversing valve is switched to the left position, so that the hydraulic oil of the low-pressure and high-flow motor pump group enters the rod chamber of the hydraulic cylinder, and the hydraulic oil in the rodless chamber flows back to the oil tank until the hydraulic cylinder retracts to the limit position. Repeat this process several times, and observe the condition of the hydraulic cylinder. Finally, the rod chamber and the rodless chamber of the hydraulic cylinder are depressurized, and all components stop working; b. The potentiometer corresponding to the proportional pressure reducing valve is reset to zero, the low-pressure and low-flow motor pump group is started, and the set pilot circuit pressure is established. The first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve are energized to connect the corresponding low-pressure pressure sensor with the rod chamber and rodless chamber of the hydraulic cylinder. The three-position four-way solenoid reversing valve is connected to the right position to allow the oil of the low-pressure and low-flow motor pump group to enter the rodless chamber of the hydraulic cylinder. At the same time, the second two-position four-way solenoid reversing valve unlocks the second hydraulic control check valve, and the oil in the rod chamber flows back to the oil tank. The potentiometer corresponding to the proportional pressure reducing valve is adjusted to make the pressure rise slowly. The deferred sensor detects the pressure in real time to obtain the instantaneous maximum pressure. After the test is completed, the hydraulic cylinder retracts according to the steps in step a. Finally, the rod chamber and rodless chamber of the hydraulic cylinder are depressurized, and all components stop working; c. The low-pressure and low-flow motor pump group starts, the pilot circuit establishes the set pressure, the potentiometer of the first proportional relief valve returns to zero, the low-pressure and high-flow motor pump group is started at zero pressure, the first proportional relief valve adjusts the pressure to the set value, the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve lose power to connect the corresponding high-pressure pressure sensor with the rod chamber and the rodless chamber of the hydraulic cylinder. After the hydraulic cylinder is extended to the limit position in step a, the low-pressure and high-flow motor pump group stops, and then the high-pressure and low-flow motor pump group starts, and the pressure of the second proportional relief valve is adjusted to make the pressure oil of the high-pressure and low-flow motor pump group enter the rodless chamber of the hydraulic cylinder. The hydraulic control check valve between the rod chamber and the two-position three-way electromagnetic reversing valve in the high-pressure circuit is opened by the pilot oil, and the hydraulic oil in the rod chamber flows back to the oil tank. After the high-pressure pressure time, the potentiometer of the second proportional relief valve returns to zero, and the high-pressure and low-flow motor pump is unloaded. At this time, the rodless chamber of the hydraulic cylinder enters the pressure holding time. After the pressure holding time, the pressure drop of the corresponding chamber of the hydraulic cylinder is observed; d. The low-pressure and low-flow motor pump group starts, the pilot circuit establishes the set pressure, the potentiometer of the first proportional relief valve returns to zero, the low-pressure and high-flow motor pump group is started at zero pressure, the first proportional relief valve adjusts the pressure to the set value, the first two-position three-way non-leakage valve and the second two-position three-way non-leakage valve lose power to connect the corresponding high-pressure pressure sensor with the rod chamber and the rodless chamber of the hydraulic cylinder. After the hydraulic cylinder retracts to the limit position in step a, the low-pressure and high-flow motor pump group stops, and then the high-pressure and low-flow motor pump group starts, and the pressure of the second proportional relief valve is adjusted to allow the pressure oil of the high-pressure and low-flow motor pump group to enter the rod chamber of the hydraulic cylinder. The hydraulic control check valve between the rodless chamber and the two-position three-way electromagnetic reversing valve in the high-pressure circuit is opened by the pilot oil, and the hydraulic oil in the rodless chamber flows back to the oil tank. After the high-pressure pressure time, the potentiometer of the second proportional relief valve returns to zero, and the high-pressure and low-flow motor pump is unloaded. At this time, the rod chamber of the hydraulic cylinder enters the pressure holding time. After the pressure holding time, the pressure drop of the corresponding chamber of the hydraulic cylinder is observed.

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