CN219911333U - Hydraulic system and pressure pulse test device - Google Patents

Abstract

The utility model relates to the technical field of pressure pulse experimental equipment, and provides a hydraulic system and a pressure pulse experimental device, wherein the hydraulic system comprises: the device comprises a hydraulic pump, an oil inlet main path, an oil return main path, a high-pressure pump, an oil inlet branch path, a multi-way valve and an oil tank; the oil inlet main path is used for communicating the multi-way valve and the oil tank; the hydraulic pump is arranged in the oil inlet main path and used for pumping hydraulic oil in the oil tank to the multi-path valve; the oil return main path is connected with the multi-way valve and the oil tank and is used for returning oil; the oil inlet branch is connected in parallel with the oil inlet main path; the high-pressure pump is arranged on the oil inlet branch and used for pumping hydraulic oil to form a high-pressure source in combination with the hydraulic pump; the multi-way valve is connected to the element to be tested through a pipeline and used for adjusting the flow and the direction to form hydraulic pulse. The hydraulic pump and the high-pressure pump can be connected through relatively simple oil ways to form a high-pressure power source together by being matched with the hydraulic pump to pump hydraulic oil together, and the hydraulic pump and the high-pressure pump are not required to be connected with a booster cylinder through complex oil ways, gas ways and the like, so that the simplification of an oil way of a hydraulic system is realized.

Description

Hydraulic system and pressure pulse test device

Technical Field

The utility model relates to the technical field of pressure pulse experimental equipment, in particular to a hydraulic system and a pressure pulse experimental device.

Background

The hydraulic cylinder is a hydraulic actuator capable of converting hydraulic energy into mechanical energy and performing linear reciprocating motion, and is widely used in working machines such as excavators, cranes, pump trucks, and the like. In the research and development stage and before leaving the factory, the hydraulic cylinder is required to carry out multiple performance tests such as test run, start pressure characteristic test, pressure resistance test and the like, and all performances of the hydraulic cylinder are generally tested through a pressure pulse test device.

In the related art, pressure pulses of various waveforms and frequency bands are generally formed by cooperation of components such as a hydraulic pump, a servo valve, a reversing valve and the like.

In practical application, in order to obtain a higher pressure source so as to meet the high-power requirement of the element to be tested on the pulse system, the hydraulic system is generally required to be connected with the booster cylinder through a complex oil way, so that the whole hydraulic system is complex.

Disclosure of Invention

The utility model provides a hydraulic system and a pressure pulse test device, which are used for reducing the problem that the whole hydraulic system is complex in the prior art, thereby realizing the simplification of an oil way of the hydraulic system.

The present utility model provides a hydraulic system comprising: the device comprises a hydraulic pump, an oil inlet main path, an oil return main path, a high-pressure pump, an oil inlet branch path and a multi-way valve;

the oil inlet main path is used for communicating the multi-way valve and the oil tank;

the hydraulic pump is arranged in the oil inlet main path and is used for pumping hydraulic oil in the oil tank to the multi-way valve;

the oil return main path is connected with the multi-way valve and the oil tank and is used for oil return;

the oil inlet branch is connected in parallel with the oil inlet main path;

the high-pressure pump is arranged on the oil inlet branch and is used for pumping hydraulic oil to form a high-pressure source in combination with the hydraulic pump;

the multi-way valve is connected to the element to be tested through a pipeline and used for adjusting the flow and the direction to form hydraulic pulse.

According to the hydraulic system provided by the utility model, the hydraulic system further comprises an energy accumulator, and the energy accumulator is connected with the oil inlet main way.

According to the hydraulic system provided by the utility model, the oil return main path is communicated with the oil inlet branch path through the oil return branch path capable of controlling on-off; when the high-pressure pump is closed, the oil return branch is communicated and is used for supplementing part of the returned hydraulic oil to the multi-way valve; when the high-pressure pump is started, the oil return branch is disconnected.

According to the hydraulic system provided by the utility model, the cartridge valve is arranged on the oil inlet branch; the cartridge valve comprises a control oil port, a bottom oil port and a side oil port; the control oil port is communicated with the bottom oil port through a damping hole on the valve core, and the control oil port and the bottom oil port are connected in series with the oil inlet branch; the side oil port is communicated with the oil return main path through the oil return branch path, and when the control oil port is not pressurized, the side oil port is communicated with the bottom oil port.

According to the hydraulic system provided by the utility model, the hydraulic system further comprises an overflow valve; the oil inlet of the overflow valve is connected with the control oil port of the cartridge valve, the oil outlet is connected with the side oil port of the cartridge valve, and when the oil pressure reaches a preset value, the overflow valve and the side oil port of the cartridge valve are opened, so that hydraulic oil flows back to the oil return main path.

The hydraulic system provided by the utility model further comprises a cooling system for circularly cooling the hydraulic oil in the oil tank.

According to the hydraulic system provided by the utility model, the cooling system comprises a water cooling device, an air cooling device and a circulating pump which are connected through pipelines; the water cooling device is connected with the air cooling device in parallel.

The utility model also provides a pressure pulse test device which comprises the hydraulic system.

The utility model provides a pressure pulse test device, which also comprises a positioning frame for mounting a component to be tested;

the locating rack includes:

the mounting plates are oppositely arranged, and shaft holes corresponding to the positions are formed in the mounting plates and are used for allowing the pin shafts to pass through and positioning the element to be tested; more than two groups of shaft holes are arranged at intervals.

According to the pressure pulse test device provided by the utility model, the positioning frame further comprises a positioning flange which is detachably connected to the mounting plate; a boss is formed at the center of the positioning flange and a through hole is formed in the positioning flange; when the positioning flange is connected with the connecting plate, the boss is correspondingly inserted into the shaft hole.

According to the pressure pulse test device provided by the utility model, the positioning frame further comprises a connecting piece, and two ends of the connecting piece are respectively connected with the pair of mounting plates.

According to the pressure pulse test device provided by the utility model, the connecting piece comprises a double-head screw rod and a nut; the double-headed screw rod sequentially penetrates through the two mounting plates and is locked through the nuts.

The beneficial effects are that:

1. the hydraulic pump and the high-pressure pump can be connected through a relatively simple oil way to form a high-pressure power source together, and the hydraulic pump and the high-pressure pump are not required to be connected with a booster cylinder through a complex oil way, an air way and the like, so that the simplification of an oil way of a hydraulic system is realized;

2. by reasonably arranging the energy accumulator, the pulse frequency can be effectively improved, the energy can be saved, and devices such as a pipeline, a multi-way valve and the like can be protected;

3. through special locating rack, can satisfy the test hydro-cylinder of different length reliably and stretch in two chambeies equal positions of volume, ensure hydraulic circuit load balance, can realize more than two test products simultaneous test simultaneously, promote test efficiency.

Drawings

In order to more clearly illustrate the utility model or the technical solutions of the prior art, the following description will briefly explain the drawings used in the embodiments or the description of the prior art, and it is obvious that the drawings in the following description are some embodiments of the utility model, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic diagram of a hydraulic system according to an embodiment of the present utility model;

FIG. 2 is a schematic view of a positioning frame according to an embodiment of the present utility model;

FIG. 3 is a second schematic view of a positioning frame according to an embodiment of the present utility model.

Reference numerals:

10. a hydraulic pump; 11. an oil inlet main path; 110. a first valve; 111. a first filter; 112. a first connection point; 113. a second connection point; 114. a first one-way valve; 115. a first pressure gauge; 116. a first pressure sensor; 12. an oil return main path; 120. a second valve; 121. a second filter; 13. a high pressure pump; 14. an oil inlet branch; 140. a second one-way valve; 141. an oil return branch; 142. a cartridge valve; 143. an overflow valve; 144. a second pressure gauge; 145. a second pressure sensor; 15. a multiway valve; 150. a third pressure gauge; 151. a third pressure sensor; 16. an oil tank; 160. a liquid level gauge; 161. a temperature sensor; 17. an accumulator; 18. a cooling system; 180. a circulation pump; 181. a water cooling device; 182. an air cooling device; 19. a positioning frame; 190. a mounting plate; 191. a connecting piece; 192. positioning a flange; 193. a fixing member; 194. and a pin shaft.

Detailed Description

For the purpose of making the objects, technical solutions and advantages of the present utility model more apparent, the technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings, and it is apparent that the described embodiments are some embodiments of the present utility model, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In order to facilitate understanding of the hydraulic system and the pressure pulse test device provided by the utility model, firstly, an application background of the hydraulic system and the pressure pulse test device is described, a plurality of parts such as various pipes, connecting pieces, hydraulic cylinders and the like are required to pass various pressure tests in a research and development stage or before delivery, the hydraulic cylinders are taken as examples, various performance tests such as test run, start-up pressure characteristic tests, pressure resistance tests and the like are required to be carried out, and the pressure pulse test device is equipment for carrying out the pressure pulse tests and forms pressure pulses through an internal hydraulic system.

In the related art, a hydraulic system generally comprises a hydraulic pump, a servo valve, a reversing valve and other components, and pressure pulses with various waveforms and frequency bands are formed through mutual matching of the components, so that the hydraulic system is suitable for detecting different performances of a hydraulic cylinder.

In order to obtain a higher pressure source so as to meet the high-power requirement of the element to be tested on the pulse system, the hydraulic system is generally required to be connected with supercharging equipment such as a supercharger, a supercharging cylinder and the like through a complex oil way, so that the whole hydraulic system is complex. Therefore, the utility model provides the hydraulic system and the pressure pulse test device, and the high-pressure power source can be obtained through relatively simple oil way connection, so that the simplification of the oil way of the hydraulic system is realized.

The hydraulic system and the pressure pulse test apparatus of the present utility model are described below with reference to fig. 1 to 3.

Referring to fig. 1, a hydraulic system includes a hydraulic pump 10, an oil-intake main passage 11, an oil-return main passage 12, a high-pressure pump 13, an oil-intake branch passage 14, and a multi-way valve 15; the two ends of the oil inlet main path 11 are respectively communicated with the oil tank 16 and the multi-way valve 15, the hydraulic pump 10 is arranged in the oil inlet main path 11 and is used for pumping hydraulic oil in the oil tank 16 to the multi-way valve 15, the multi-way valve 15 is connected to an element to be tested through a pipeline, and the flow, the pressure and the flow direction of the hydraulic oil can be adjusted through the multi-way valve 15, so that various waveform hydraulic pulses are formed.

One end of the oil return main path 12 is communicated with an oil return port of the multi-way valve 15, and the other end of the oil return main path is communicated with the oil tank 16 for oil return; the oil inlet branch 14 is arranged in parallel with the oil inlet main path 11, the high-pressure pump 13 is arranged on the oil inlet branch 14, and hydraulic oil can be pumped jointly by the high-pressure pump 13 and the hydraulic pump 10, so that a high-pressure power source is formed, and the high-power requirement of the element to be tested on the pulse system is met.

In practical application, hydraulic oil in an oil tank 16 can be pumped into a multi-way valve 15 through a hydraulic pump 10, and hydraulic pulses with various waveforms can be formed through adjustment of the flow, the pressure and the flow direction by the multi-way valve 15; the high-pressure pump 13 can cooperate with the hydraulic pump 10 to pump hydraulic oil together, and the hydraulic pump can form a high-pressure power source together by being connected through a relatively simple oil way, and a pressurizing cylinder is not required to be connected through a complex oil way, an air way and the like, so that the simplification of an oil way of a hydraulic system is realized.

A first valve 110 and a first filter 111 are connected to the oil inlet main path 11 at a position close to the oil tank 16; wherein, the first valve 110 is used for controlling the flow of the oil inlet main path 11; the first filter 111 is located downstream of the first valve 110 and is used for filtering the hydraulic oil pumped to the multi-way valve 15 to ensure the normal operation of the multi-way valve 15. Likewise, the oil return main path 12 is connected with a second valve 120 and a second filter 121, where the second valve 120 is used to control on-off of the oil return main path 12, and the second filter 121 is located upstream of the second valve 120 and is used to filter the returned hydraulic oil to avoid the return of impurities to the oil tank 16.

The oil inlet end of the oil inlet branch 14 is connected with the oil inlet main path 11 to form a first connecting point 112 positioned at the upstream, and the oil outlet end of the oil inlet branch 14 is connected with the oil inlet main path 11 to form a second connecting point 113 positioned at the downstream. The first connection point 112 is located downstream of the first filter 111, and the hydraulic pump 10 is located between the first connection point 112 and the second connection point 113.

When the hydraulic pump 10 and the high-pressure pump 13 are started simultaneously, one part of the pumped hydraulic oil is filtered by the first filter 111, and the other part of the pumped hydraulic oil passes through the oil inlet main path 11 and the oil inlet branch path 14, and the two parts of hydraulic oil are converged and flow into the multi-way valve 15, so that a high-pressure source is provided.

In another embodiment, the oil inlet end of the oil inlet branch 14 may be directly connected to the oil tank 16, and when the hydraulic pump 10 and the high-pressure pump 13 are started at the same time, the hydraulic oil pumped by the hydraulic pump 10 and the high-pressure pump 13 flows into the multi-way valve 15 after being collected. It will be appreciated that when the inlet leg 14 is so configured, a valve and filter may be provided on the inlet leg 14 to filter and regulate the hydraulic oil flowing through the inlet leg 14.

An accumulator 17 is connected to the downstream of the hydraulic pump 10, and the accumulator 17 can be charged by the hydraulic pump 10, so that the instantaneous discharge of hydraulic oil from the accumulator 17 can increase the flow rate of the hydraulic oil when the accumulator operates, thereby supplementing the large flow rate required when the water hammer wave is generated. Meanwhile, by reasonably arranging the energy accumulator 17, the pulse frequency can be effectively improved, energy sources are saved, and devices such as a pipeline, the multi-way valve 15 and the like are protected.

Specifically, the connection point of the accumulator 17 and the oil inlet main path 11 is located between the first connection point 112 and the second connection point 113, so that the accumulator 17 can form water hammer waves of different sizes in cooperation with the hydraulic pump 10, the hydraulic pump 10 and the high-pressure pump 13.

A first check valve 114 is provided between the accumulator 17 and the hydraulic pump 10, and a second check valve 140 is provided downstream of the high-pressure pump 13. The reverse flow of the hydraulic oil can be prevented by the first check valve 114 and the second check valve 140.

The oil inlet main path 11 is provided with a first pressure gauge 115 and a first pressure sensor 116 at the downstream of the second connection point 113, the oil pressure entering the reversing valve can be monitored through the first pressure gauge 115, and pressure signals can be fed back to the PLC controller through the first pressure sensor 116, so that the running states of the hydraulic pump 10 and the high-pressure pump 13 are regulated and controlled.

The oil return main path 12 is communicated with the oil inlet branch path 14 through an oil return branch path 141 capable of controlling on-off; when the high-pressure pump 13 is closed, the oil return branch 141 is communicated, and part of the returned hydraulic oil can be supplemented to the multi-way valve 15 through the oil return branch 141; when the high-pressure pump 13 is started, the oil return branch 141 is disconnected, and the hydraulic oil in a high-pressure state is prevented from flowing back to the return main path through the oil return branch 141.

Specifically, the cartridge valve 142 is disposed on the oil inlet branch 14, the cartridge valve 142 has three oil ports, namely, a control oil port, a bottom oil port and a side oil port, wherein the control oil port and the bottom oil port of the cartridge valve 142 are communicated through a damping hole on the valve core, and the control oil port and the bottom oil port are connected in series on the oil inlet branch 14. Under the action of the spring in the valve core, the valve core is lifted, the side oil port and the bottom oil port are in a communicated state, and the oil return branch 141 is communicated with the side oil port. When the high-pressure pump 13 is in a closed state, the control oil port is pressureless, the side oil port and the bottom oil port are in a communication state, and part of the returned hydraulic oil flows through the oil return branch 141, the cartridge valve 142 and the oil inlet branch 14 and flows back to the multi-way valve 15 through the oil inlet main path 11, so that the hydraulic oil of the multi-way valve 15 is supplemented.

When the high-pressure pump 13 is in an open state, the control oil port is at high pressure and compresses the valve core, so that the side oil port is closed, high-pressure hydraulic oil flows through the damping hole on the valve core and enters the oil inlet main path 11, and a high-pressure source is supplemented.

It should be noted that, the cartridge valve 142 is in the mature prior art, and according to actual needs, various types of cartridge valves 142 can be obtained by market, and the above is only a brief description of the structure and working principle of the cartridge valve 142, and it is to be understood that the cartridge valve 142 itself has other structures, but the specific structure is not a main utility model point of the present utility model, and the present utility model does not make any changes to the structure inside the cartridge valve 142, so the specific structure is not repeated.

The hydraulic system further comprises an overflow valve 143 for regulating and controlling the oil pressure in the oil inlet branch 14; specifically, an oil inlet of the overflow valve 143 is connected with a control oil port of the cartridge valve 142, and an oil outlet is connected with a side oil port of the cartridge valve 142; when the high-pressure pump 13 operates, under the action of high-pressure hydraulic oil, the valve core is compressed to enable the valve core to be pressed down, the side oil port is closed, and the hydraulic oil flows through a damping hole on the valve core; when the pressure is abnormally increased to the set pressure of the overflow valve 143, the overflow valve 143 is opened, the control oil port is communicated with the side oil port, the valve core is lifted under the action of the spring in the cartridge valve 142, and the side oil port is opened, so that high-pressure hydraulic oil flows into the backflow branch through the overflow valve 143 and the side oil port of the cartridge valve 142 for pressure relief.

The oil inlet branch 14 is connected with a second pressure gauge 144 and a second pressure sensor 145; the oil pressure in the oil feed branch 14 can be monitored by the second pressure gauge 144; the second pressure sensor 145 may generate a pressure signal and feed back to the PLC controller, and adjust the operation state of the high pressure pump 13 through the PLC controller, so that emergency stop may be performed when the pressure is abnormal, and safety of the test is ensured.

The multi-way valve 15 is formed by integrating an electric proportional valve and an overflow valve 143, so that the functions of pressure control, flow control, reversing and the like are achieved, the multi-way valve 15 is of a mature prior art, multi-way valves 15 of various types can be obtained through market according to actual requirements, and the specific structure of the multi-way valve is not a main improvement point of the utility model, so that the specific structure is not repeated.

The push-pull force parameter value required by the test is set to the PLC through a human-computer interface, a current signal is output to the electric proportional valve amplifier through an internal algorithm, the electric proportional valve set is controlled through switching of an electromagnetic force control valve set generated by an electromagnetic coil, and the electromagnetic force generated by the electromagnetic coil is in direct proportion to the current, so that the required pressure and flow rate can be obtained by controlling the electromagnetic coil current through the PLC, and the speed and the pressure in the axial direction of the oil cylinder to be tested are obtained, so that automatic control is realized.

The multi-way valve 15 is connected with one or more stations through pipelines, and can be specifically selected according to actual requirements; in this embodiment, the multi-way valve 15 is connected with two stations through two groups of pipelines, and through the two stations, two components to be tested can be simultaneously satisfied independently or simultaneously, so that the test period is shortened, and the cost of the test is saved.

A third pressure gauge 150 and a third pressure sensor 151 are arranged on a pipeline of the multi-way valve 15 connected with the element to be tested; the pressure of the hydraulic oil input into the element to be measured can be detected by the third pressure gauge 150; the third pressure sensor 151 can convert the pressure signal into an electrical signal and feed back the electrical signal to the PLC controller to regulate the working state of the multi-way valve 15.

The hydraulic system further comprises a cooling system 18 for circulating cooling of the hydraulic oil in the tank 16. Specifically, the cooling system 18 includes a circulation pump 180, a water cooling device 181 and an air cooling device 182 connected by pipelines; wherein, water cooling plant 181 and air cooling plant 182 are the mature prior art, and the accessible is commercially available, and both pass through the parallelly connected setting of pipeline, can make hydraulic oil circulate between air cooling plant 182, water cooling plant 181 and oil tank 16 through circulating pump 180 to cool down the hydraulic oil, guarantee the long-time normal use of device.

It will be appreciated that valves and filters may also be provided on the lines of the cooling system 18 to filter the hydraulic oil entering and exiting the tank 16, avoiding impurities from entering the tank 18 or the cooling system 18, and ensuring proper operation of the hydraulic system.

The tank 16 is connected with a liquid level meter 160 and a temperature sensor 161; wherein the level gauge 160 may monitor the level of the liquid in the tank 16; the temperature sensor 161 can monitor the temperature of the hydraulic oil and feed back a temperature signal to the PLC controller to control the operating state of the cooling system 18.

The pressure pulse test device provided by the utility model is described below, and the pressure pulse test device described below and the hydraulic system described above can be referred to correspondingly.

Referring to fig. 2 and 3, a pressure pulse test apparatus includes a test stand, a positioning frame 19, and the hydraulic system described above; the locating rack 19 is arranged on the test bed and is used for installing and locating the cylinder to be tested.

Specifically, the positioning frame 19 is integrally made of a metal material, and can play a role in protection when a tested sample fails or a hydraulic pipeline fails, so that the positioning frame has the characteristics of stability, reliability and convenience in use.

Specifically, the positioning frame 19 includes a mounting plate 190, a connecting member 191, a positioning flange 192, and a fixing member 193; the positioning plates are oppositely arranged in a pair and fixedly connected to the test bed in a welding mode. The two mounting plates 190 are provided with shaft holes corresponding to each other in position, and at least two groups of shaft holes are arranged at intervals. The oil cylinder pulsation pressurization test with various strokes can be satisfied by selecting the shaft holes at different positions.

The connector 191 includes a stud bolt and a nut, and the stud bolt is locked by the nut after passing through the two mounting plates 190 in sequence. The two mounting plates 190 can be integrally connected by the connecting member 191, thereby improving the overall strength of the spacer 19.

It will be appreciated that the stud and nut are just one of many configurations of the connector 191, and that in alternative embodiments, the connector 191 may be a conventional stud or other rod-like member having two ends connected to two mounting plates 190.

The positioning flange 192 is formed with a boss at the center thereof and a hole at the center thereof, the positioning flange 192 is detachably coupled to the mounting plate 190 by a fixing member 193, and the boss thereof is correspondingly inserted into the shaft hole. By changing the positioning flange 192 for different models, hydraulic cylinders of different earring models can be accommodated. Specifically, the fixing member 193 is a screw.

When the cylinder to be tested is actually installed, firstly, a shaft hole at a proper position is selected according to the stroke of the hydraulic cylinder, then, a proper positioning flange 192 is selected according to the types of earrings on the head and the cylinder body of the hydraulic cylinder, the positioning flange 192 is connected to the mounting plate 190 through a fixing piece 193 and matched with the shaft hole at a specific position, and then, a pin roll 194 penetrates through a through hole in the center of the positioning flange 192 to complete the connection of the hydraulic cylinder.

The novel innovation point of the utility model is that: the hydraulic pump 10 can pump the hydraulic oil in the oil tank 16 into the multi-way valve 15, the multi-way valve 15 can regulate the flow, the pressure and the flow direction, various wave-shaped hydraulic pulses can be formed, the high-pressure pump 13 can pump the hydraulic oil together with the hydraulic pump 10, the two can form a high-pressure power source together through relatively simple oil ways, the pressure cylinder is not required to be connected through complex oil ways, gas ways and the like, and the simplification of the oil ways of a hydraulic system is realized; by reasonably arranging the energy accumulator 17, the pulse frequency can be effectively improved, the energy can be saved, and the devices such as a pipeline, the multi-way valve 15 and the like can be protected; the special locating rack 19 can reliably meet the requirement that the tested oil cylinders with different lengths extend to the equal positions of the volumes of the two cavities, ensure the load balance of the hydraulic circuit, simultaneously realize the simultaneous test of more than two tested products and improve the test efficiency.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present utility model, and are not limiting; although the utility model has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present utility model.

Claims (10)

1. A hydraulic system, comprising: the hydraulic pump (10), the oil inlet main path (11), the oil return main path (12), the high-pressure pump (13), the oil inlet branch path (14), the multi-way valve (15) and the oil tank (16);

the oil inlet main path (11) is used for communicating a multi-way valve (15) with the oil tank (16);

the hydraulic pump (10) is arranged on the oil inlet main path (11) and is used for pumping hydraulic oil in the oil tank (16) to the multi-way valve (15);

the oil return main way (12) is connected with the multi-way valve (15) and the oil tank (16) and is used for oil return;

the oil inlet branch (14) is connected in parallel with the oil inlet main path (11);

the high-pressure pump (13) is arranged on the oil inlet branch (14) and is used for pumping hydraulic oil in combination with the hydraulic pump (10) to form a high-pressure source;

the multi-way valve (15) is connected to the element to be tested through a pipeline and is used for adjusting the flow and the direction to form hydraulic pulse.

2. The hydraulic system according to claim 1, further comprising an accumulator (17), said accumulator (17) being connected to said main oil intake circuit (11).

3. The hydraulic system according to claim 1, characterized in that the oil return main circuit (12) and the oil inlet branch circuit (14) are communicated by an oil return branch circuit (141) which can be controlled to be switched on and off; when the high-pressure pump (13) is closed, the oil return branch (141) is communicated and is used for supplementing part of the returned hydraulic oil to the multi-way valve (15); when the high-pressure pump (13) is turned on, the oil return branch (141) is disconnected.

4. A hydraulic system according to claim 3, characterized in that the oil inlet branch (14) is provided with a cartridge valve (142); the cartridge valve (142) comprises a control oil port, a bottom oil port and a side oil port; the control oil port is communicated with the bottom oil port through a damping hole on the valve core, and the control oil port and the bottom oil port are connected in series with the oil inlet branch (14); the side oil port is communicated with the oil return main path (12) through the oil return branch path (141), and when the control oil port is not pressurized, the side oil port is communicated with the bottom oil port.

5. The hydraulic system of claim 4, further comprising a relief valve (143); the oil inlet of the overflow valve (143) is connected with the control oil port of the cartridge valve (142), the oil outlet is connected with the side oil port of the cartridge valve (142), and when the oil pressure reaches a preset value, the overflow valve (143) and the side oil port of the cartridge valve (142) are opened, so that hydraulic oil flows back to the oil return main path (12).

6. The hydraulic system according to any one of claims 1-5, further comprising a cooling system (18) for circulating cooling of the hydraulic oil in the tank (16).

7. The hydraulic system according to claim 6, characterized in that the cooling system (18) comprises a water cooling device (181), an air cooling device (182) and a circulation pump (180) connected by pipelines; the water cooling device (181) and the air cooling device (182) are connected in parallel.

8. A pressure pulse testing device comprising a hydraulic system according to any one of claims 1-7.

9. Pressure pulse test device according to claim 8, characterized in that it further comprises a positioning frame (19) for mounting the element to be tested;

the positioning frame (19) comprises:

a pair of mounting plates (190) which are oppositely arranged, wherein shaft holes corresponding to the positions are arranged on the mounting plates (190) and are used for allowing a pin shaft (194) to pass through and position the element to be tested; more than two groups of shaft holes are arranged at intervals.

10. The pressure pulse testing device according to claim 9, characterized in that the positioning frame (19) further comprises a positioning flange (192) detachably connected to the mounting plate (190); a boss is formed at the center of the positioning flange (192) and a through hole is formed; when the positioning flange (192) is connected to the connecting plate, the boss is correspondingly inserted into the shaft hole.