阅读说明：本技术 一种拖拉机液压多路阀用试验装置及其试验方法 (Testing device and testing method for tractor hydraulic multi-way valve ) 是由 王晓伟 杜晓晓 胡伟 加志东 杨文欣 欧阳永 吴健 张凯 周钰 甘霖 王南旗 于 2020-05-22 设计创作，主要内容包括：一种拖拉机液压多路阀用试验装置,包括油箱组件、动力组件、PLC控制组件、待测多路阀、模拟负载油缸、提升器和箱式基台,本发明的一种用于拖拉机液压多路阀的试验装置,可实现不同流量、不同温度、不同系统压力条件下,液压多路阀性能的测定,为液压多路阀批量制造的工艺过程控制提供技术和参数指导,把好出厂质量关。(The invention discloses a test device for a hydraulic multi-way valve of a tractor, which comprises an oil tank assembly, a power assembly, a P L C control assembly, a multi-way valve to be tested, a simulated load oil cylinder, a lifter and a box type base platform.)

1. A test device for a hydraulic multiway valve of a tractor comprises an oil tank assembly (1), a power assembly (2), a P L C control assembly, a multiway valve (8) to be tested, a simulated load oil cylinder (9), a lifter (10) and a box base (11), wherein the multiway valve (8) to be tested and the P L C control assembly are arranged on the box base (11), the test device is characterized in that the oil tank assembly (1) is connected with an oil inlet pipeline (3) for outputting oil, a main oil return pipeline (4) for returning the oil, an overflow oil return pipeline (5) and a system oil return pipeline (6), the oil inlet pipeline (3) is sequentially provided with the oil inlet power assembly (2), a pressure gauge I (7) and a two-position three-way electromagnetic valve I (12) according to the conveying direction of the oil, one oil outlet of the two-position three-way electromagnetic valve I (12) is connected with an oil inlet of the multiway valve (8) to be tested through a high-pressure stop valve (13), the other oil outlet is connected with the oil return assembly (1) through the oil return pipeline (6), the flow meter I (6) is further provided with an overflow valve (14) connected with an overflow valve (5) in parallel connection mode, the overflow valve (14) for regulating pressure gauge I) and an overflow valve (14) for regulating pressure of the overflow valve (14) and an overflow valve (14) for regulating the overflow valve (14) to be tested, the overflow valve (14) and an overflow valve (14) are further connected with the overflow valve (14) in parallel connection, the oil return pipeline (1);

the multi-way valve (8) to be tested is further connected with a hydraulic output oil pipeline (18) and a hydraulic input oil pipeline (19), a pressure gauge III (20) and a two-position three-way electromagnetic valve II (21) are sequentially arranged on the hydraulic output oil pipeline (18) according to the oil conveying direction, one oil outlet of the two-position three-way electromagnetic valve II (21) is connected with a rodless cavity of the simulation load oil cylinder (9), a rod cavity of the simulation load oil cylinder (9) is connected with a rod cavity of the lifter (10), the other oil outlet is connected with a rodless cavity of the lifter (10), the rod cavity of the lifter (10) is further connected with the multi-way valve (8) to be tested through the hydraulic input oil pipeline (19) to form a loop, and the hydraulic input oil pipeline (19) is provided with a pressure gauge IV (22);

the P L C control assembly comprises a P L C controller (23), an operation button (24), a display (25) and an oil pipe connecting port (26), wherein a plurality of interfaces are arranged on the oil pipe connecting port (26), and the plurality of interfaces are respectively connected with a plurality of working oil ports on the multi-way valve (8) to be tested in a one-to-one correspondence mode through hoses.

2. The test device for the tractor hydraulic multi-way valve according to claim 1, characterized in that: the oil tank assembly (1) and the box type base station (11) are both arranged on the ground, and the power assembly (2) is arranged on the oil tank assembly (1).

3. The test device for the tractor hydraulic multi-way valve according to claim 1 or 2, characterized in that: the multi-way valve (8) to be tested is arranged on the box type base platform (11) through a multi-way valve clamp (27).

4. The test device for the tractor hydraulic multi-way valve according to claim 1, characterized in that: the oil tank assembly (1) comprises a hydraulic oil tank (101), a thermometer (102), a cooler (103), a heater (104) and a plurality of oil filters (105), wherein the thermometer (102), the cooler (103) and the heater (104) are arranged in the hydraulic oil tank (101), the cooler (103) is arranged on a main oil return pipeline (4), and the oil filters (105) are arranged on an oil inlet pipeline (3) and the main oil return pipeline (4).

5. The test device for the tractor hydraulic multi-way valve according to claim 4, wherein: the number of the oil filters (105) is three, two of the oil filters are arranged at the front end and the rear end of the power assembly (2) on the oil inlet pipeline (3), and the other oil filter is arranged at the front end of the cooler (103) on the main oil return pipeline (4).

6. The test device for the tractor hydraulic multi-way valve according to claim 1, characterized in that: power component (2) including frequency modulation motor (201), shaft coupling (202) and gear pump (203), frequency modulation motor (201) and gear pump (203) are all fixed on oil tank subassembly (1), and frequency modulation motor (201) drive gear pump (203) through shaft coupling (202) and carry out the operation.

7. The test device for the tractor hydraulic multi-way valve according to claim 1, characterized in that: the multi-way valve (8) to be tested comprises an oil inlet valve (801), a main valve (802) and an oil return valve (803), the oil inlet valve (801), the main valve (802) and the oil return valve (803) are fastened and connected together through a stud bolt (807), one end of the oil inlet valve (801) is provided with a safety valve (811), the oil inlet valve (801) is also provided with a working oil port P and a working oil port T, the main valve (802) is provided with a one-way valve (808), a single-double left-right regulating valve (809), a working oil port A and a working oil port B, the main valve (802) is internally provided with a main valve core assembly (804), the main valve core assembly (804) is pressed in the main valve (802) through a spring cover (810) arranged at the end part of the main valve (802), an operating mechanism assembly (805) for operating and adjusting the main valve (802) is arranged outside the main valve (802), and an oil outlet seat (806) is further arranged on the oil return valve (803).

8. The test device for the tractor hydraulic multi-way valve according to claim 7, characterized in that: the working oil port A is respectively connected with rodless cavities of the simulation load oil cylinder (9) and the lifter (10) through a two-position three-way electromagnetic valve II (21), and the working oil port B is connected with rod cavities of the simulation load oil cylinder (9) and the lifter (10).

9. The method for testing the tractor hydraulic multi-way valve test device according to the claim 1, which is characterized by comprising the following steps:

(1) fixing a gear pump on the oil tank assembly (1) through a connecting flange, and then connecting the gear pump with a frequency modulation motor by adopting a coupler; fixing the multi-way valve (8) to be tested on the box type base station (11) through a multi-way valve clamp (27), and then correspondingly connecting a plurality of interfaces on an oil pipe connecting port (26) with a plurality of working oil ports on the multi-way valve (8) to be tested one by one through a hose, and ensuring that the oil leakage phenomenon cannot occur at the joint;

(2) starting a switch in a P L C control assembly, setting temperature and flow technological parameters on a display (25), turning off an emergency stop switch in an operation knob, enabling a heater or a cooler in an oil tank assembly (1) to act, heating or cooling oil in the oil tank assembly (1), and enabling the oil temperature to be stabilized to a set temperature value of the display (25), then putting an 'adjusting/working' button in the operation knob at an 'working' position, pressing a hydraulic starting button and a test starting button, operating a power assembly (2), enabling the flow of the oil in an oil inlet pipeline (3) to reach a technological set flow, and automatically setting the flow to the set flow value;

(3) the multi-way valve (8) to be tested is adjusted to a neutral position, then, the back pressure value of the multi-way valve (8) to be tested is remotely adjusted and controlled by adjusting the parallel overflow valve II (17), the parallel overflow valve I (15) is adjusted, and the system pressure of the whole testing device is remotely adjusted and controlled; continuously operating the multi-way valve (8) to be tested for 10 times, and checking whether the multi-way valve (8) to be tested has ascending, neutral, descending, floating reversing performance and flexible valve rod return; observing whether the external leakage oil phenomenon exists on each junction surface of the multi-way valve (8) to be tested, observing pressure gauges of a hydraulic output oil pipeline (18) and a hydraulic input oil pipeline (19), adjusting the full opening pressure of a safety valve in the multi-way valve (8) to be tested to a specified value, and locking the safety valve;

(4) adjusting the multi-way valve (8) to be tested to a neutral position, starting timing when the pressure change of the whole test device is stable, maintaining the pressure for 1min, and recording the pressure drop values of a pressure gauge III (20) and a pressure gauge IV (22) as an important index for measuring the suspension static settlement of the tractor; when the true value of the suspension static settlement of the tractor needs to be checked by sampling, starting a two-position three-way electromagnetic valve II (21), closing a power assembly (2) when a lifter (10) drives a suspension system to be lifted to the highest value, starting timing, and recording the descending data of a pressure gauge III (20) and a pressure gauge IV (22) within half an hour;

(5) and finishing the test, removing the residual oil in the multi-way valve (8) to be tested, recording the experimental process, and analyzing the experimental data.

Technical Field

The invention relates to the technical field of multi-way valve testing, in particular to a testing device and a testing method for a tractor hydraulic multi-way valve.

Background

The multiway valve belongs to a high-precision hydraulic element and is an indispensable part for hydraulic output configuration of a tractor, and horizontal type forced pressure and vertical type forced pressure configurations developed by the tractor in recent years rely on the multiway valve to gradually replace a traditional lifter with a distributor structure.

The most common faults of the market three-pack service reaction multi-way valve element are internal leakage, external leakage and valve blockage. The main reasons are that 1, the matching clearance between the valve rod and the valve body is large, the abrasion of the valve rod and the valve body is accelerated due to long-term use or uncleanness of oil, the matching sealing surface is damaged, and internal oil drainage is caused. 2. If the bolts are not as strong as torque, the valve body will warp. In addition, the joint surface of the valve body is damaged or the O-shaped ring is damaged during assembly, and leakage occurs between the valve bodies under the action of oil pressure. 3. If the cleanliness between the valve body and the valve rod is poor, great resistance is generated or a valve rod reset spring is deformed and damaged, so that the valve rod is difficult to reset, a plurality of paths of valve rods cannot be flexibly reset, and the grooves are communicated with the oil duct to generate internal leakage. 4. The sealing between the valve rod and the valve body is realized by an O-shaped sealing ring, and if the sealing ring is not assembled properly and is trimmed, hydraulic oil flows out along the valve rod under the action of system pressure, so that oil leakage of the valve body is caused. 5. The valve rod and the valve body are small in fit clearance or poor in cleanliness, and valve clamping can be caused under the high-temperature environment work of the system. 6. If the precast oil duct in the inner cavity of the valve body blank has casting defects such as air holes, sand holes, cracks and the like, internal leakage is generated.

In view of the above, it is necessary to provide a practical testing apparatus and testing method for the quality process control research of the tractor hydraulic multi-way valve. The device for testing the hydraulic multi-way valve of the tractor is capable of measuring the pressure required by a hydraulic system at an adjustable temperature by the multi-way valve with large or small flow, simulating the static settlement value of a suspension system required by the tractor, monitoring the quality characteristics of multi-way valve elements in real time, realizing the factory test of multi-series multi-way valve products, providing effective test data for the control of the technological process of the batch manufacturing of the hydraulic multi-way valve, and is easy to operate, simple in method, safe and reliable.

Disclosure of Invention

The technical purpose of the invention is as follows: the testing device and the testing method for the hydraulic multi-way valve of the tractor can realize the performance measurement of the hydraulic multi-way valve under the conditions of different flow rates, different temperatures and different system pressures, provide technical and parameter guidance for the process control of the batch manufacturing of the hydraulic multi-way valve, and have good factory quality.

The invention solves the technical problems by adopting the technical scheme that the test device for the hydraulic multiway valve of the tractor comprises an oil tank assembly, a power assembly, a P L C control assembly, a multiway valve to be tested, a simulated load oil cylinder, a lifter and a box base, wherein the multiway valve to be tested and the P L C control assembly are arranged on the box base, the oil tank assembly is connected with an oil inlet pipeline for outputting oil, a main oil return pipeline, an overflow oil return pipeline and a system oil return pipeline for refluxing the oil, the oil inlet pipeline is sequentially provided with the power assembly, a pressure gauge I and a two-position three-way electromagnetic valve I according to the oil conveying direction, one oil outlet of the two-position three-way electromagnetic valve I is connected with an oil inlet of the multiway valve to be tested through a high-pressure stop valve, the other oil outlet is connected with the oil tank assembly through the system oil return pipeline, the system oil return pipeline is also provided with a flow gauge, the oil inlet pipeline is provided with the position I and is connected with the oil tank assembly through the overflow pipeline, the overflow pipeline is also provided with the oil return pipeline, the overflow valve I and the overflow valve II for regulating the backpressure of the multiway valve to be tested, and the overflow valve II are also arranged between the overflow valve and the main oil return pipeline;

the multi-way valve to be tested is also connected with a hydraulic output oil pipeline and a hydraulic input oil pipeline, a pressure gauge III and a two-position three-way electromagnetic valve II are sequentially arranged on the hydraulic output oil pipeline according to the oil conveying direction, one oil outlet of the two-position three-way electromagnetic valve II is connected with a rodless cavity of the simulation load oil cylinder, a rod cavity of the simulation load oil cylinder is connected with a rod cavity of the lifter, the other oil outlet of the simulation load oil cylinder is connected with a rodless cavity of the lifter, the rod cavity of the lifter is also connected with the multi-way valve to be tested through the hydraulic input oil pipeline to form a loop, and a pressure gauge IV is arranged on the hydraulic input oil pipeline;

the P L C control assembly comprises a P L C controller, an operating button, a display and an oil pipe connector, wherein a plurality of interfaces are arranged on the oil pipe connector, and the plurality of interfaces are respectively connected with a plurality of working oil ports on the multi-way valve to be tested in a one-to-one correspondence mode through hoses.

Preferably, the oil tank assembly and the box-type base station are both arranged on the ground, and the power assembly is arranged on the oil tank assembly.

Preferably, the multi-way valve to be tested is arranged on the box type base station through a multi-way valve clamp.

Preferably, the tank assembly includes a hydraulic tank, a thermometer, a cooler and a heater provided in the hydraulic tank, and a plurality of oil filters, wherein the cooler is provided on the main oil return line, and the oil filters are provided on the oil inlet line and the main oil return line.

Preferably, the number of the oil filters is three, two of the oil filters are arranged at the front end and the rear end of the power assembly on the oil inlet pipeline, and the other oil filter is arranged at the position of the front end of the cooler on the main oil return pipeline.

Preferably, the power assembly include frequency modulation motor, shaft coupling and gear pump, frequency modulation motor and gear pump are all fixed on the oil tank subassembly, and the frequency modulation motor drives the gear pump through the shaft coupling and carries out the operation.

Preferably, the multi-way valve that awaits measuring include inlet valve, main valve and scavenge valve, this inlet valve, main valve and scavenge valve pass through three stud fastening and link together, a relief valve is installed to the one end of inlet valve, has still seted up working oil port P and working oil port T on the inlet valve, is provided with check valve, single two governing valves about, working oil port A and working oil port B on the main valve, and the inside of main valve is equipped with main valve core assembly, and this main valve core assembly compresses tightly in the main valve through a spring cap that main valve tip set up, and the outside of main valve is provided with and is used for controlling the operating mechanism assembly of adjusting to it, the scavenge valve on still install out the oil port seat.

Preferably, the working oil port A is respectively connected with the simulation load oil cylinder and a rodless cavity of the lifter through a two-position three-way electromagnetic valve II, and the working oil port B is connected with the simulation load oil cylinder and a rod cavity of the lifter.

A test method of a tractor hydraulic multi-way valve comprises the following steps:

1. fixing a gear pump on the oil tank assembly through a connecting flange, and then connecting the gear pump with a frequency modulation motor by adopting a coupler; fixing the multi-way valve to be tested on a box type base station through a multi-way valve clamp, and then connecting a plurality of interfaces on an oil pipe connecting port with a plurality of working oil ports on the multi-way valve to be tested in a one-to-one correspondence manner through a hose, and ensuring that the oil leakage phenomenon cannot occur at the joint;

2. starting a switch in a P L C control assembly, setting temperature and flow technological parameters on a display, turning off an emergency stop switch in an operation knob, enabling a heater or a cooler in an oil tank assembly to act, heating or cooling oil in the oil tank assembly, and enabling the oil temperature to be stabilized to a set temperature value of the display;

3. the multi-way valve to be tested is adjusted to a neutral position, then, the back pressure value of the multi-way valve to be tested is remotely adjusted by adjusting the parallel overflow valve II, the parallel overflow valve I is adjusted, and the system pressure of the whole testing device is remotely adjusted; continuously controlling the multi-way valve to be tested to check whether the multi-way valve to be tested has ascending, neutral, descending, floating reversing performance and flexible valve rod return; observing whether the external leakage oil phenomenon exists on each junction surface of the multi-way valve to be tested, observing pressure gauges of a hydraulic output oil pipeline and a hydraulic input oil pipeline, adjusting the full opening pressure of a safety valve in the multi-way valve to be tested to a specified value, and locking the safety valve;

4. adjusting the multi-way valve to be tested to a neutral position, starting timing when the pressure change of the whole test device is stable, maintaining the pressure for 1min, and recording the pressure drop values of a pressure gauge III and a pressure gauge IV to serve as an important index for measuring the suspension static settlement of the tractor; when the true value of the suspension static settlement of the tractor needs to be checked, starting a two-position three-way electromagnetic valve II, closing a power assembly when a lifter drives a suspension system to be lifted to the highest value, starting timing, and recording descending data of a pressure gauge III and a pressure gauge IV within half an hour;

5. and (4) finishing the test, removing residual oil in the multi-way valve to be tested, recording the test process, and analyzing the test data.

Has the advantages that:

1. the test device for the tractor hydraulic multi-way valve is simple in structure and reasonable in design. 1) The process match grinding clearance range between the valve rod and the valve body can be reasonably selected according to the pressure drop value of the neutral position pressure maintaining test of the multi-way valve to be tested, so that the static settlement of the tractor suspension is ensured; 2) basic data are provided for actually required shape tolerance of the valve hole and the valve rod, and a specific data range is provided for stably honing the valve hole in batches and grinding the high-precision valve rod; 3) the phenomenon of internal leakage and external leakage caused by assembly defects, such as improper assembly of an O-shaped ring, edge cutting, different fastening torques of bolts, damage to a valve body joint surface and the like, is effectively avoided, and the yield is improved; 4) the problem of internal leakage caused by casting defects such as air holes, sand holes, cracks and the like in the precast oil duct in the inner cavity of the valve body blank can be detected; 5) whether the quality of purchased parts is qualified or not can be checked, and whether flexible reset of a plurality of paths of valve rods can be influenced or not under a high-pressure environment such as a large spring cover, an operating lever support, a slide valve spring and the like; 6) the testing device can calibrate and adjust different temperature, pressure and flow parameters, monitor the quality characteristics of the multi-way valve element in real time, realize the delivery test of a plurality of series of multi-way valve products, provide effective test data for the process control of the hydraulic multi-way valve manufacturing process, is simple and easy to implement, and has good use value.

2. The test method for the hydraulic multi-way valve of the tractor has the advantages of simple steps, convenience in operation, capability of quickly and accurately measuring the performance of the multi-way valve to be measured, and good practical effect.

Drawings

FIG. 1 is a hydraulic schematic of the present invention;

FIG. 2 is a schematic structural view of a power module according to the present invention;

FIG. 3 is a schematic view of the box-type base of the present invention;

FIG. 4 is a schematic structural diagram of a tested multi-way valve according to the present invention;

the reference numbers of the device comprise 1, an oil tank assembly, 101, a hydraulic oil tank, 102, a thermometer, 103, a cooler, 104, a heater, 105, an oil filter, 2, a power assembly, 201, a frequency modulation motor, 202, a coupler, 203, a gear pump, 3, an oil inlet pipeline, 4, a main oil return pipeline, 5, an overflow oil return pipeline, 6, a system oil return pipeline, 7, a pressure gauge I, 8, a multi-way valve to be tested, 801, an oil inlet valve, 802, a main valve, 803, an oil return valve, 804, a main valve core assembly, 805, an operating mechanism assembly, 806, an oil outlet seat, 807, a double-head bolt, 808, a one-way valve, 809, a single-double left and right adjusting valve, 810, a spring cover, 811, a safety valve, 9, a simulation load oil cylinder, 10, a lifter, 11, a box type base, 12, a two-position three-way electromagnetic valve I, 13, a high-pressure stop valve, 14, a flow meter, 15, a parallel overflow valve I, 16, a pressure gauge II, 17, a parallel overflow valve II, 18, a hydraulic output circuit, 19, a hydraulic input circuit, 20, a pressure gauge III, 21, a three-way electromagnetic valve II.

Detailed Description

The invention is described in further detail below with reference to the accompanying drawings:

as shown in the figure, the test device for the hydraulic multi-way valve of the tractor comprises an oil tank assembly 1, a power assembly 2, a P L C control assembly, a multi-way valve 8 to be tested, a simulated load oil cylinder 9, a lifter 10 and a box base 11, wherein the multi-way valve 8 to be tested and the P L C control assembly are arranged on the box base 11, the oil tank assembly 1 and the box base 11 are arranged on the ground, the power assembly 2 is arranged on the oil tank assembly 1, a two-position three-way electromagnetic valve I12 and a two-position three-way electromagnetic valve II 21 are respectively connected between the power assembly 2 and the multi-way valve 8 to be tested, the simulated load oil cylinder 9 and the lifter 10, a thermometer 102 is arranged in a hydraulic oil tank 101, a flowmeter 14 is arranged on a main oil return pipeline 4 and a system oil return pipeline 6, four pressure gauges are respectively arranged on an oil inlet pipeline 3, a main oil return pipeline 4, a hydraulic oil output pipeline 18 and a hydraulic oil input pipeline 19, two overflow valves are respectively connected between the power assembly 2 and the oil tank assembly 1, a high-pressure stop valve 637 is arranged between the oil pipe I12 and the multi-way valve I to be tested, the multi-way valve 8 to be tested, the box base is respectively connected with a box base 20 through a simulated load oil cylinder 26C control connector 23 and a lifting oil cylinder 23, a lifting control connector 23, a lifting oil cylinder 23 is connected with a lifting oil cylinder 23.

The oil tank assembly 1 comprises a hydraulic oil tank 101, a thermometer 102, a cooler 103 and a heater 104 which are arranged in the hydraulic oil tank 101, and a plurality of oil filters 105, wherein the hydraulic oil tank 101 is fixed on the ground through anchor bolts; the cooler 103 is arranged on the main return line 4; a thermometer 102 and a heater 104 are installed in the hydraulic oil tank 101; the port P1 806 of the multi-way valve 8 to be tested is connected with the oil tank 101 through a main oil return pipeline 4; the oil filter 105 selects filter elements with different precisions to be respectively installed on the oil inlet pipeline 3 and the main oil return pipeline 4, the number of the oil filter 105 is three, two of the filter elements are arranged at the front end and the rear end of the power component 2 on the oil inlet pipeline 3, and the other filter element is arranged at the position, located at the front end of the cooler 103, on the main oil return pipeline 4, so that the hydraulic oil in the system is subjected to three-stage filtration, and the cleanliness of the test bed system is guaranteed to reach the standard.

The power assembly 2 comprises a frequency modulation motor 201, a coupler 202 and a gear pump 203, the frequency modulation motor 201 is connected with a power supply and is fixed on the oil tank assembly 1, and the gear pump 203 is fixed on the oil tank assembly 1 through a connecting flange; and the frequency modulation motor 201 drives the gear pump 203 to operate through the coupler 202. The power component 2 is connected with an oil inlet of the multi-way valve 8 through an oil inlet pipeline 3, and the power component 2 is connected with the oil tank 101 through the oil inlet pipeline 3; the flow of the system reaches the flow required by the test by adjusting the rotating speed of the frequency modulation motor 201.

The two-position three-way electromagnetic valve I12 is connected between the power assembly 2 and the oil tank assembly 1, so that the equipment has two operation modes of adjustment and work. In the adjusting mode, a hydraulic starting operation button is pressed, a display hydraulic motor is lightened, a display system on the display can display no-load flow through a flow meter of a pipeline, and a flow meter on a main oil return pipeline 4 displays test flow when back pressure is 2 MPa. The mode is mainly used for manual control debugging in maintenance; and the two-position three-way electromagnetic valve II 21 is connected between the multi-way valve 8 and the simulated load oil cylinder 9 and the lifter 10, and can respectively control and start the simulated load oil cylinder 9 and the lifter 10 to carry out a contrast selectivity test.

The manometer in the testing device is used for monitoring test pressure, includes: the pressure gauge I7, the pressure gauge II 16, the pressure gauge III 20 and the pressure gauge IV 22 are arranged on the oil inlet pipeline 3 and display the system pressure of the test bed; the pressure gauge II is arranged on the main oil return pipeline 4 and displays the set back pressure value of the tested multi-way valve 8; the pressure gauge III is arranged on the hydraulic output pipeline 18 and displays the pressure value of the port A of the tested multi-way valve, namely the full-open pressure value of the tested multi-way valve 8; the pressure gauge IV is arranged on the hydraulic input pipeline 19 and displays the pressure value of the port B of the tested multi-way valve, namely the set back pressure value of the tested multi-way valve 8;

two parallel overflow valves in the test device are used for adjusting the test pressure. The parallel overflow valve I15 is arranged on the overflow oil return pipeline 5, and the system pressure of the test bed can be remotely regulated and controlled by adjusting the two overflow valves; the parallel overflow valve II 17 is arranged on the main oil return pipeline 4 of the tested multi-way valve 8, and the backpressure value of the tested multi-way valve 8 can be remotely regulated and controlled by adjusting the two overflow valves.

The tested multiplex valve 8 is a tested valve element and comprises an oil inlet valve 801, a main valve 802, an oil return valve 803, a main valve core assembly 804, an operating mechanism assembly 805, an oil outlet seat 806, a stud bolt 807, a one-way valve 808, a single-double left and right adjusting valve 809, a spring cover 810 and a safety valve 811. The check valve 808 is pressed on the main valve 802, and the oil inlet valve 801, the main valve 802 and the oil return valve 803 are fastened and connected together by the stud 807 in sequence, so that the deformation of the main valve hole is not more than the honing allowance. And grinding the main valve core after honing the main valve hole. The main valve core 804 is inserted into the main valve hole, and the operating mechanism core 805 is assembled by pressing the main valve core with the spring cover 810. The outlet seat 806 is attached to the oil return valve 803. The single and double left and right regulating valves 809 are installed on the main valve 802 to ensure flexible rotation. The safety valve 811 is installed on the oil inlet valve 801, adjusted to the full opening pressure value required by the product and locked. Under the action of the operating mechanism assembly 805, the tested multiplex valve 8 can realize the functions of ascending, neutral, descending and floating.

The tested multi-way valve 8 is arranged on the multi-way valve clamp 27, and two output ports A, B of the tested multi-way valve 8 are respectively connected with the upper cavity and the lower cavity of the simulation load cylinder 9 and the lifter 10. The flow direction of the high-pressure hydraulic oil is reversed under the action of the operating mechanism assembly 805, so that the telescopic motion of the simulated load oil cylinder 9 and the lifting motion of the lifter 10 are controlled, and the factory quality of the multi-way valve 8 is checked one by one.

The P L C control assembly comprises a P L C controller 23, an operation button 24, a display 25 and an oil pipe connecting port 26, wherein a plurality of interfaces are arranged on the oil pipe connecting port 26, and the plurality of interfaces are respectively connected with a plurality of working oil ports on the multi-way valve 8 to be tested in a one-to-one correspondence mode through hoses.

The test method and the working principle of the test device for the tractor hydraulic multi-way valve are as follows:

[1] mounting, namely mounting a gear pump on a flange, and connecting the gear pump with a frequency modulation motor by using a coupler; the multi-way valve is fixed on a test bed clamp, an oil pipe is connected and a joint nut is arranged, when an oil way is connected, the ports P \ T \ A \ B \ P1 need to correspond to each other, and the phenomenon of joint oil leakage can not occur.

[2] And after the power is on, opening the main switch of the equipment, starting a computer and opening the multi-way valve test bed. Temperature and flow process parameters are set on the display. Turning on the emergency stop switch, enabling the heater to work, enabling the oil temperature of the test bed to be automatically heated to a set temperature value, and enabling the cooler to work if the temperature exceeds the set value, and keeping the temperature of the system stable; the 'adjustment/working' button is placed at the 'working' position, the hydraulic starting button and the test starting button are pressed, the rotating speed of the frequency modulation motor is changed, the gear pump is driven by the coupler to achieve the process set flow, and the set flow value is automatically set.

[3] And when the slide valve is in the neutral position, the parallel overflow valve II is adjusted, so that the back pressure value of the tested multi-way valve is remotely adjusted and controlled. Adjusting the parallel overflow valve I to realize remote regulation and control of the system pressure of the test bed; continuously operating the tested valve operating mechanism for 10 times, and checking whether rising, neutrality, descending, floating reversing performance and valve rod returning are flexible; observing whether each joint surface has the phenomenon of external oil leakage; the operating mechanism is pulled to observe the pressure gauge at the port A or the port B, the full-opening pressure of the safety valve is adjusted to a specified value, and the safety valve is locked.

[4] When the slide valve moves to the neutral position quickly, timing is started when the pressure change is stable, pressure maintaining is carried out for 1min, and the pressure drop value of the port A or the port B is recorded and is used as an important index for measuring the suspension static settlement of the tractor. If the true value of the suspension static settlement of the tractor is checked, the two-position three-way electromagnetic valve can be started, the lifter drives the suspension system to be lifted to the highest value, the gear pump of the test bed is closed, and the time is recorded and the descending data of half an hour is recorded.

[5] And after the test is finished, removing residual oil in the inner cavity of the valve body, and placing the valve body on a designated appliance in order. Problems occurring in the experimental process are summarized, and experimental data are analyzed.

The test device for the hydraulic multi-way valve of the tractor can realize the adjustment of the pressure required by a hydraulic system under the condition of adjustable temperature of the large or small flow multi-way valve, provides effective test data for the control of the manufacturing process of the hydraulic multi-way valve, and closes the factory quality.

Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will recognize that changes may be made in the form and detail of the embodiments described herein without departing from the spirit and scope of the invention. The invention is intended to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the appended claims.