Dual-way air-controlled hydraulic reversing valve with different pressures and flows

Abstract

The present invention discloses a dual-path pneumatically controlled hydraulic reversing valve with different pressures and flows, mainly relating to the technical field of hydraulic system control, comprising a valve body (1), a lifting valve stem (6), a reversing valve stem (9), a reversing cylinder (12), and a lifting cylinder (18). The invention of the composite valve can convert a pressure oil source entering the valve into two hydraulic systems with different pressures and flows, that is, a hydraulic oil pump can be used in conjunction with the valve to replace two hydraulic systems consisting of two oil pumps (or a double pump) and two hydraulic reversing valves.

Description

Technical Field

[0001] The invention mainly relates to the technical field of hydraulic system control, in particular to a two-way gas-controlled hydraulic reversing valve with different pressures and flows. Background Art

[0002] At present, most of the transportation of bulk materials such as sand, gravel, minerals, coal, and slag is done by dump trucks. During the transportation process, these vehicles will cause the goods to scatter and fall to varying degrees, and the wind will blow dust all over the sky, which seriously endangers environmental protection requirements. In recent years, with the development and progress of society and the governance of environmental protection, the above-mentioned vehicles must be equipped with automatic or semi-automatic closing devices, such as the currently used push-pull tarpaulin cover, double-split butterfly cover, integral environmental protection cover, etc.

[0003] Although dump trucks are of various types and series, they basically all use hydraulic lifting and unloading devices for manual automatic unloading. Although the hydraulic lifting and unloading devices of various dump trucks are different, the working principles of various hydraulic lifting systems are roughly the same. The working pressure of these hydraulic lifting systems is generally in the range of 15-22Mpa. The opening and closing of the above-mentioned closing device of the environmental protection cover can be roughly divided into three types. The first type is to use a motor to drive the reducer to drive the opening and closing of the environmental protection cover, which is mostly used in the tarpaulin cover structure. The second type is to use a motor to drive the oil pump to establish an independent hydraulic system to control the opening and closing of the environmental protection cover, which is mostly used in the butterfly cover structure, and the system working pressure is generally in the range of 8-15Mpa. The third type is to use the gearbox and power take-off of the vehicle through the universal transmission shaft to the oil pump support to drive a double oil pump, and one of the oil outputs is used to connect a lifting valve that controls unloading, and its working pressure is generally in the range of 15-22Mpa. The other link is connected to a hydraulic reversing valve that controls the environmental protection cover → a two-way balancing valve, → an environmental protection cover cylinder. It is mostly used for double butterfly covers and integral environmental protection cover structures. It is also used to connect a hydraulic reversing valve that controls the environmental protection cover → a two-way oil motor to drive the tarpaulin cover structure, and its working pressure is generally in the range of 6-15Mpa.

[0004] Based on the above, it has been proved in practice that the first type has a small overload potential and is prone to burning the motor due to irregular loading of cargo and obstruction of the opening and closing of the tarpaulin cover, and has a high failure rate. The second type is that there are two hydraulic systems on the same vehicle, one is a hydraulic lifting and unloading device driven by the gearbox power take-off to drive the oil pump, and the other is an independent hydraulic station driven by a motor, which is specially used for the opening and closing of the environmental protection cover. This solution makes the structure complex, occupies a large space, has high cost, and is prone to burning the motor. Both of the above structures have the problem that the motor is installed on the surface of the vehicle body, which is inevitably exposed to the sun and rain, causing temperature rise and humidity, destroying insulation, and easily causing the motor to burn. In view of the defects and shortcomings of the above two types, some manufacturers have changed to the third structure, which has the defects of high cost, complex structure, heavy weight, inconvenient installation, chaotic and complex pipelines, large installation space, high failure rate, and inconvenient maintenance. Summary of the invention

[0005] In view of the deficiencies and defects in the prior art, the present invention provides a two-way gas-controlled hydraulic reversing valve with different pressures and flows.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A two-way pneumatically controlled hydraulic reversing valve with different pressures and flows is characterized in that it comprises a valve body, a reversing cylinder and a lifting cylinder, wherein a lifting valve stem and a reversing valve stem are respectively arranged in the valve body, the lifting valve stem is connected to an oil inlet hole P, the reversing valve stem is connected to an oil return port 1 T and an oil return port 2 T, the lifting valve stem and the reversing valve stem are communicated through an oil passage K, an open cover oil port and a closed cover oil port connected to the reversing valve stem are respectively arranged on the valve body, a lifting oil port connected to the lifting valve stem is arranged on the valve body, and an oil return port 1 T and an oil return port 2 T are respectively arranged on the valve body. The oil return channel L is connected to the front oil return channel L and the rear oil return channel L which are respectively connected to the two ends of the valve body and penetrate the lifting valve stem and the reversing valve stem. A secondary pressure relief valve assembly is provided at the connection between the front oil return channel L and the oil return channel L between the reversing valve stem and the lifting valve stem. A primary pressure relief valve assembly is provided at the front oil return channel L and the oil inlet hole P on one side of the lifting valve stem. One end of the lifting valve stem is placed in the valve body and the other end is connected to the lifting cylinder. A fixed lifting piston is provided in the lifting cylinder. The end of the rod passes through the lifting fixed piston and connects to the lifting moving piston. A lifting adjustment rod is provided on the lifting cylinder rear cover of the lifting cylinder. The lifting adjustment rod is connected to the slow-drop piston. A lifting return spring is provided on the lifting valve rod between the valve body and the lifting fixed piston. On the lifting cylinder, a descending air port is provided between the lifting fixed piston and the lifting moving piston, a lifting air port is provided between the lifting moving piston and the slow-drop piston, and a slow-drop air port is provided between the slow-drop piston and the lifting cylinder rear cover. The diameter of the lifting moving piston is smaller than that of the slow-drop piston; a reversing valve One end of the rod is placed in the valve body and connected to the adjusting seat on the valve body, and the other end is connected to the reversing cylinder. A fixed reversing fixed piston is arranged in the reversing cylinder. The end of the reversing valve rod passes through the reversing fixed piston and is connected to the reversing moving piston. A reversing adjusting rod is arranged on the reversing cylinder back cover on the reversing cylinder. A reversing return spring is arranged on the reversing valve rod between the valve body and the reversing fixed piston. On the reversing cylinder, a closing air port is arranged between the reversing fixed piston and the reversing moving piston, and an opening air port is arranged between the reversing moving piston and the reversing cylinder back cover.

[0008] As a further improvement of the present invention, the middle parts of the lifting valve stem and the reversing valve stem are respectively provided with undercut grooves, and the undercut grooves are respectively connected to the oil passages K.

[0009] As a further improvement of the present invention, the oil return port 1 T and the oil return port 2 T are interconnected.

[0010] As a further improvement of the present invention, a vent cover is provided on the valve body at one end of the lifting valve stem.

[0011] As a further improvement of the present invention, an adjusting screw is provided on the adjusting seat.

[0012] As a further improvement of the present invention, the reversing valve stem is fixedly connected to the reversing return spring.

[0013] As a further improvement of the present invention, a spare oil port connected to the lifting valve stem is provided on the valve body.

[0014] As a further improvement of the present invention, a relief valve spring is provided on the secondary pressure relief valve.

[0015] As a further improvement of the present invention, a sealing ring is provided on the oil return port T and connected to the oil tank valve seat.

[0016] As a further improvement of the present invention, a diverter valve needle is provided in the oil passage K.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The invention of the composite valve can convert a pressure oil source of an inlet valve into two hydraulic systems with two different pressures and different flows, that is, a hydraulic oil pump and the valve can be used together to replace two oil pumps (or two hydraulic systems composed of a double pump and two hydraulic reversing valves).

[0019] 1. For example, the third structure in the second item of the first background technology mentioned above will not be repeated. If the composite valve is used, the original double gear oil pump can be changed to a single one. For example, the flow rate of the double pump is 100 / 50ml respectively, and the flow rate of 100ml can be selected. If a double pump is used originally, the failure rate of the double pump is much higher than that of the single pump, and the service life is short. Moreover, because the volume of the double pump is relatively large and the weight is relatively heavy, the oil pump must be installed separately on an independent special support, and the power from the power take-off to the oil pump is connected with the universal transmission shaft. If a single oil pump is used instead, it can be directly installed on the power take-off and directly connected to the power take-off, thereby saving a lot of installation space, eliminating the universal transmission shaft and the oil pump support mechanism, saving the oil suction and oil supply pipelines connected to the oil pump, and reducing the leakage points. At the same time, it saves installation time, reduces the failure rate of the mechanism, improves production efficiency, and greatly reduces production costs. It has the advantages of compact structure, reasonable layout, beautiful appearance, reliable performance, long service life, convenient maintenance, etc. It is very popular among users.

[0020] 2. For example, the third structure in the second item of the first background technology mentioned above will not be repeated. The original lifting valve used for unloading the cargo box and the reversing valve for controlling the opening and closing of the environmental protection cover can be replaced with a composite valve of the present invention to improve all the original functions. The two valves in the original third structure are generally installed on the valve seat of the hydraulic oil tank due to the limitation of the installation space on the hydraulic oil tank. The other valve is installed separately on the special valve seat next to the hydraulic oil tank. The oil inlet of the valve must be connected to the oil pump, and the oil return must be connected to the hydraulic oil tank. In this way, the hydraulic control system on the vehicle occupies a large installation space, is not centralized, and uses many pipelines, which makes it difficult to straighten and conceal the pipelines, and the cost is high. If this valve is used, it can be directly installed on the valve seat of the hydraulic oil tank, just like the lifting valve in the original structure, which is equivalent to removing the environmental protection cover opening and closing reversing valve installed separately next to the hydraulic oil tank in the original structure. This saves installation space, reduces production costs, saves high-pressure oil pipes, reduces pressure drop and friction heat caused by oil supply resistance, reduces the heating rate of hydraulic oil, and improves mechanical efficiency. It reduces possible leakage points and improves reliability, making the entire hydraulic control system compact, small, light, reasonable, neatly arranged, beautiful, and easy to maintain.

[0021] 3. The design of the composite valve is universal for integral environmental protection cover dump trucks, double-split butterfly cover dump trucks, tarpaulin cover dump trucks driven by hydraulic motors, etc. This has laid a foundation for the universality of selected components in the automotive manufacturing industry. The valve is not only used for this purpose, but can also be widely used in other similar hydraulic circuits. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments:

[0023] Figure 1 It is a cross-sectional view of a two-way gas-controlled hydraulic reversing valve with different pressures and flows according to the present invention;

[0024] Figure 2 It is a cross-sectional view of AA of the present invention;

[0025] Figure 3 It is a structural schematic diagram of the opening of the environmental protection cover of the present invention;

[0026] Figure 4 It is a schematic structural diagram of the closed environmental protection cover of the present invention;

[0027] Figure 5 This is a structural schematic diagram of the cargo box lifting of the present invention;

[0028] Figure 6 This is a schematic diagram of the structure of the cargo box descending according to the present invention;

[0029] Figure 7This is a schematic diagram of the structure of the slow lowering of the cargo box of the present invention;

[0030] Main view; Top view; Left view; Right view; Top view; Bottom view;

[0031] In the figure: 1 valve body, 2 diverter valve needle, 3 sealing ring, 4 secondary pressure relief valve, 5 primary pressure relief valve, 6 lifting valve stem, 7 ventilation cover, 8 relief valve spring, 9 reversing valve stem, 10 adjusting screw, 11 adjusting seat, 12 reversing cylinder, 13 reversing return spring, 14 reversing fixed piston, 15 reversing moving piston, 16 reversing cylinder rear cover, 17 reversing adjusting rod, 18 lifting cylinder, 19 lifting fixed piston, 20 lifting moving piston, 2 1 lifting adjustment rod, 22 slow lowering piston, 23 lifting cylinder rear cover, 24 lifting return spring, 25 open cover oil port, 26 closed cover oil port, 27 lifting oil port, 29 spare oil port, 30 descending air port, 31 lifting air port, 32 slow lowering air port, 33 open cover air port, 34 closed cover air port, 35 oil tank valve seat, P oil inlet hole, K oil channel, L oil return channel, L1 front oil return channel, L2 rear oil return channel, T1 oil return port one, T2 oil return port two. DETAILED DESCRIPTION

[0032] In order to make the technical scheme and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments. It should be understood that the specific implementation methods described herein are only used to understand the present invention and are not used to limit the present invention. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0033] According to the above, we know that the working pressure of these hydraulic lifting systems is generally in the range of 15-22Mpa, and the flow rate is generally required to be 70-100L. The working pressure of the environmental protection cover is generally in the range of 6-15Mpa, and the flow rate is generally required to be 20-50L. The two do not work at the same time. It can be seen that the former has high pressure and large flow, while the latter has relatively low pressure and small flow. We have made a comprehensive design based on this feature and invented the "composite gas-controlled hydraulic reversing valve with two different pressures and flows", referred to as the composite valve. The characteristics of this valve can be summarized as using a quantitative oil pump to supply oil, which can realize two control oil circuits with different pressures and flows running alternately, and only one composite valve can replace the original oil circuit in the third structural scheme controlled by two valves. This valve is not only used for this, but can also be widely used in similar hydraulic circuits.

[0034] A two-way pneumatically controlled hydraulic reversing valve with different pressures and flows comprises a valve body 1, a reversing cylinder 12 and a lifting cylinder 18. A lifting valve stem 6 and a reversing valve stem 9 are respectively arranged in the valve body 1. The lifting valve stem 6 is connected to an oil inlet hole P, and the reversing valve stem 9 is connected to an oil return port 1 T1 and an oil return port 2 T2. The lifting valve stem 6 and the reversing valve stem 9 are communicated with each other through an oil passage K. An opening oil port 25 and a closing oil port 26 connected to the reversing valve stem 9 are respectively arranged on the valve body 1. A lifting oil port 27 connected to the lifting valve stem 6 is arranged on the valve body 1. The oil return port 1 T1 and the oil return port 2 T2 are connected to an oil return channel L, and the oil return channel L is respectively connected to the oil return ports placed in the valve body 1, a front oil return channel L1 and a rear oil return channel L2 are provided at both ends of the lifting valve stem 6 and the reversing valve stem 9, a secondary pressure relief valve assembly 4 is provided at the connection between the front oil return channel L1 and the oil return channel L between the reversing valve stem 9 and the lifting valve stem 6, a primary pressure relief valve assembly 5 is provided at the front oil return channel L1 and the oil inlet hole P on one side of the lifting valve stem 6, one end of the lifting valve stem 6 is placed in the valve body 1, and the other end is connected to the lifting cylinder 18, a fixed lifting fixed piston 19 is provided in the lifting cylinder 18, an end of the lifting valve stem 6 passes through the lifting fixed piston 19 and is connected to the lifting moving piston 20, and a lifting cylinder rear cover 23 of the lifting cylinder 18 is provided with a A lifting adjustment rod 21, wherein the lifting adjustment rod 21 is connected to a slow-drop piston 22, a lifting return spring 24 is provided on the lifting valve stem 6 between the valve body 1 and the lifting fixed piston 19, a descending air port 30 is provided between the lifting fixed piston 19 and the lifting movable piston 20 on the lifting cylinder 18, a lifting air port 31 is provided between the lifting movable piston 20 and the slow-drop piston 22, a slow-drop air port 32 is provided between the slow-drop piston 22 and the lifting cylinder rear cover 23, and the diameter of the lifting movable piston 20 is smaller than the diameter of the slow-drop piston 22; one end of the reversing valve stem 9 is placed in the valve body 1, connected to the adjustment seat 11 on the valve body 1, and the other end is connected to the reversing cylinder 12, in A fixed reversing fixed piston 14 is provided in the reversing cylinder 12, and the end of the reversing valve stem 9 passes through the reversing fixed piston 14 and is connected to the reversing moving piston 15. A reversing adjusting rod 17 is provided on the reversing cylinder rear cover 16 on the reversing cylinder 12, and a reversing return spring 13 is provided on the reversing valve stem 9 between the valve body 1 and the reversing fixed piston 14. On the reversing cylinder 12, a closing air port 34 is provided between the reversing fixed piston 14 and the reversing moving piston 15, and an opening air port 33 is provided between the reversing moving piston 15 and the reversing cylinder rear cover 16; a vent hood 7 is provided on the valve body 1 and one end of the lifting valve stem 6, and an adjusting screw 10 is provided on the adjusting seat 11.

[0035] The lifting valve stem 6 and the reversing valve stem 9 are respectively provided with recessed grooves in the middle, and the recessed grooves are respectively connected to the oil passages K. The valve body 1 is provided with a spare oil port 29 connected to the lifting valve stem 6. The secondary pressure relief valve 4 is provided with a relief valve spring 8. The oil return port T1 is provided with a sealing ring 34, which is connected to the oil tank valve seat 35. The oil passage K is provided with a diverter valve needle 2.

[0036] The working principle is only taken as an example of a hydraulic dump truck with an environmental protection cover

[0037] 1: The valve stem is in the middle position when not in operation

[0038] like Figure 1 :This valve is generally installed on the valve seat of the hydraulic oil tank of a dump truck with an environmental protection cover. The return oil is directly returned to the oil tank through the return oil port 1 T1. The return oil port 1 T1 and the return oil port 2 T2 are connected. When the valve needs to be installed in other parts, the return oil port 2 T2 can be selected and connected to the hydraulic oil tank with a return oil pipe.

[0039] This valve can realize the control of two sets of hydraulic systems with different pressures and flows. One set controls the unloading work of the single-acting oil cylinder of hydraulic lifting and unloading. The pressure of this system is adjusted and determined by the primary pressure relief valve 5, generally within the range of 15-22Mpa. Its flow is determined by the selected matching quantitative hydraulic oil pump. The other set controls the opening and closing of the environmental protection cover with a double-acting oil cylinder, or the driving work of the bidirectional hydraulic motor. The pressure of this system is adjusted and determined by the secondary pressure relief valve 4, generally within the range of 8-15Mpa. Its flow is adjusted and realized by the diverter valve needle 2.

[0040] The above two systems can achieve different pressures, different flows, independent control, and alternating operation with one quantitative oil pump. When the right-end lifting cylinder 18 and the reversing cylinder 12 are not working, the lifting valve stem 6 and the reversing valve stem 9 are in a balanced state as shown in the figure under the pre-pressure of the two lifting return springs 24 and the reversing return spring 13. At this time, the lifting oil port 27 is completely closed by the lifting valve stem 6, and the lifting oil cylinder is in a static state, that is, the cargo box is in a static state. The closing oil port 26 and the opening oil port 25 are both closed by the reversing valve stem 9, and the oil cylinder or hydraulic motor that drives the environmental protection cover is in a static state, that is, the environmental protection cover is in a static state.

[0041] When the oil supply pump supplies oil into the valve body through the oil inlet, it passes through the oil channel K through the countersunk groove in the middle of the lifting valve stem 6, enters the countersunk groove in the middle of the reversing valve stem 9, and returns oil without pressure through the oil return port. At this moment, the hydraulic system is in an unloading state, and the supporting power loss is very small.

[0042] 2: The opening reversing valve stem of the environmental protection cover is on the left end

[0043] like Figure 3: When the cover closing air port 34 exhausts air and the cover opening air port 33 intakes air, the reversing piston 15, under the action of air pressure, drives the reversing valve stem 9 and overcomes the axial thrust of the reversing return spring 13, and moves to the left until the left end adjusting screw 10 is limited. At this time, the pressure oil enters the valve body through the oil inlet P, passes through the oil channel K through the recessed groove in the middle of the lifting valve stem 6, enters the recessed groove at the right end of the reversing valve stem 9, and directly passes through the cover opening oil port 25 to supply oil to the cover opening end of the opening and closing oil cylinder; the other end of the oil cylinder returns oil to the cover closing oil port 26, passes through the recessed groove on the left side of the reversing valve stem 9, passes through the rear oil return channel L2, the oil return channel L, and returns to the hydraulic oil tank through the oil return port; the cover opening operation is performed.

[0044] If overload occurs during operation, the secondary pressure relief valve 4 will automatically open to return oil through the rear oil return channel L2 and the oil return channel L. When the opening speed needs to be adjusted, the cross-sectional size of the annular slit at point E can be adjusted by adjusting the screw 10 to control the oil return speed to achieve the ideal operating speed.

[0045] 3: The closed reversing valve stem of the environmental protection cover is on the right end

[0046] like Figure 4 :When the opening air port 33 exhausts air and the closing air port 34 intakes air, the reversing piston 15, under the action of air pressure, drives the reversing valve stem 9 and overcomes the axial thrust of the reversing reset spring 13, and moves to the right until the right end reversing regulating rod 17 limits the position. At this time, the pressure oil enters the valve body through the oil inlet, passes through the oil channel K through the recessed groove in the middle of the lifting valve stem 6, enters the recessed groove on the left end of the reversing valve stem 9, and directly passes through the closing oil port to supply oil to the closing end of the opening and closing oil cylinder; the other end of the oil cylinder returns oil to the opening oil port, passes through the recessed groove on the right side of the reversing valve stem 9, passes through the front oil return channel, the oil return channel L, and returns to the hydraulic oil tank through the oil return port; the closing operation is performed. If an overload occurs during operation, the overflow valve 4 will be automatically opened to return oil through the rear oil return channel and the oil return channel L. When the closing speed needs to be adjusted, the reversing regulating rod 17 can be used to adjust the cross-sectional size of the annular slit at point F to control the speed of oil return to achieve the ideal operating speed.

[0047] 4: Cargo box lifting lift valve stem is on the left end

[0048] like Figure 5 : When the lowering air port 30 exhausts, the lifting air port 31 intakes, and the slow lowering air port 32 exhausts, the lifting piston 20, under the action of air pressure, drives the lifting valve stem 6 and overcomes the axial thrust of the lifting return spring 24, and moves to the left until the dead point, and the slow lowering piston 22 moves to the right until the dead point. At this time, the pressure oil enters the valve body through the oil inlet P, passes through the countercut groove at the right end of the lifting valve stem 6, and directly passes through the lifting oil port to supply oil to the lifting oil cylinder; lifting and unloading work is performed.

[0049] During the lifting process, if an overload occurs during operation, the relief valve 5 will automatically open to return oil through the rear return oil channel L2 and the return oil channel L to unload the oil, thereby playing an overload safety protection role for the lifting system.

[0050] 5: The cargo box lowering and lifting valve stem is on the right end

[0051] like Figure 6 : When the lowering air port takes in air, the lifting air port exhausts air, and the slow-lowering air port exhausts air, the lifting piston 20, under the action of air pressure, drives the lifting valve stem 6 and overcomes the axial thrust of the lifting return spring 24, and moves to the right until the dead point, and the slow-lowering piston is at the rightmost dead point. At this time, the oil pump supplies oil into the valve body through the oil inlet, passes through the two countersunk grooves at the left end of the lifting valve stem 6, passes through the oil channel K, and enters the two countersunk grooves in the middle of the reversing valve stem 9, and unloads and returns the oil through the return oil port. The hydraulic oil in the lifting cylinder is pressed back to the lifting oil port by the gravity of the cargo box, and returns to the oil tank through the countersunk groove at the right end of the lifting valve stem 6, the front return oil channel, the return oil channel L, and the return oil port. As can be seen from the above, the lowering of the cargo box is achieved by its own gravity, and there is no effect even if the oil pump is turned off.

[0052] 6: The cargo box slow lowering and lifting valve stem is in the middle position and slightly to the right

[0053] like Figure 7:When the cargo box is descending normally, it will descend faster and faster due to the acceleration of gravity. At the moment of descending to the bottom, it will exert a downward impact force on the frame chassis, causing corresponding damage. To avoid this phenomenon, you can switch to slow descent mode when it is close to the bottom. In the normal descent mode, switch the slow descent air port from exhaust to intake. The diameter of the lifting piston 20 is Φ46 mm, and the compressed area on its left side is 15.08 square centimeters. The diameter of the slow descent piston 22 is Φ47.5 mm, and the compressed area on its right side is 15.71 square centimeters. The area difference between the two is 0.63 square centimeters. When the working air pressure is 0.7Mpa, the difference in pneumatic thrust generated by the two is 4.41kg. Because the thrust of the slow-drop piston 22 is greater than the force of the moving piston 20 plus the lifting return spring 24, the slow-drop piston 22 will move 7 mm to the left to the dead point of the cylinder step, and at the same time drive the lifting adjustment rod 21 to push the moving piston 20 to move the lifting valve stem 6 to the left to the position shown in the figure, and the lifting return spring 24 will be released and push the spring seat to the left to the corresponding shoulder of the lifting valve stem 6. At this time, the oil pump supplies oil to the valve body through the oil inlet P, through the two countersunk grooves at the left end of the lifting valve stem 6, through the oil channel K, into the two countersunk grooves in the middle of the reversing valve stem 9, and unload and return oil through the return oil port. The hydraulic oil in the lifting oil cylinder is pressed back to the lifting oil port by the gravity of the cargo box, and returns to the oil tank through the countersunk groove at the right end of the lifting valve stem 6, the slow-drop notch H, the front return oil channel, and the return oil channel L through the return oil port. The speed of descent at this time is related to the opening size of the slow-descent notch H. The opening size of the slow-descent notch H can be adjusted by lifting the adjustment rod 21. The smaller the opening, the slower the descent speed, and the larger the opening, the opposite. The ideal slow-descent speed can be achieved by adjusting according to the actual situation to avoid the impact caused by rapid descent to the bottom.

[0054] During the normal descent, the descent will get faster and faster according to the principle of gravity acceleration. You can also click slow descent at any time to achieve the purpose of controlling the descent speed.

[0055] It is worth noting that in the description of the present invention, the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operate in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0056] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

Claims

1. Two-way gas-controlled hydraulic reversing valve with different pressures and flows, characterized by: The invention comprises a valve body (1), a reversing cylinder (12), and a lifting cylinder (18). A lifting valve stem (6) and a reversing valve stem (9) are respectively arranged in the valve body (1). The lifting valve stem (6) is connected to an oil inlet hole (P), and the reversing valve stem (9) is connected to an oil return port 1 (T1) and an oil return port 2 (T2). The lifting valve stem (6) and the reversing valve stem (9) are connected to each other through an oil passage (K). An open-cover oil port (25) connected to the reversing valve stem (9) is respectively arranged on the valve body (1). , a cover oil port (26), a lifting oil port (27) connected to the lifting valve stem (6) is provided on the valve body (1), the return oil port 1 (T1) and the return oil port 2 (T2) are connected to the return oil channel L, and the return oil channel L is respectively connected to the front return oil channel (L1) and the rear return oil channel (L2) which are arranged at both ends of the valve body (1) and pass through the lifting valve stem (6) and the reversing valve stem (9), and the front return oil channel (L1) and the return oil channel L2 between the reversing valve stem (9) and the lifting valve stem (6) are connected. A secondary pressure relief valve assembly (4) is provided at the connection between the lifting valve stem (6) and the lifting valve stem (6); a primary pressure relief valve assembly (5) is provided at the front oil return passage (L1) and the oil inlet hole (P) on one side of the lifting valve stem (6); one end of the lifting valve stem (6) is placed in the valve body (1) and the other end is connected to the lifting cylinder (18); a fixed lifting fixed piston (19) is provided in the lifting cylinder (18); the end of the lifting valve stem (6) passes through the lifting fixed piston (19) and is connected to the lifting moving piston (20); a lifting valve stem (6) is provided on the lifting cylinder rear cover (23) of the lifting cylinder (18) A lifting adjustment rod (21), the lifting adjustment rod (21) is connected to a slow-drop piston (22), a lifting return spring (24) is provided on a lifting valve rod (6) between the valve body (1) and the lifting fixed piston (19), a lowering air port (30) is provided between the lifting fixed piston (19) and the lifting movable piston (20) on the lifting cylinder (18), a lifting air port (31) is provided between the lifting movable piston (20) and the slow-drop piston (22), and a slow-drop air port (32) is provided between the slow-drop piston (22) and the lifting cylinder rear cover (23), The diameter of the lifting piston (20) is smaller than the diameter of the slow-down piston (22); one end of the reversing valve stem (9) is placed in the valve body (1) and connected to the adjustment seat (11) on the valve body (1); the other end is connected to the reversing cylinder (12); a fixed reversing fixed piston (14) is provided in the reversing cylinder (12); the end of the reversing valve stem (9) passes through the reversing fixed piston (14) and is connected to the reversing piston (15); a reversing adjusting seat (11) is provided on the reversing cylinder rear cover (16) on the reversing cylinder (12); A section rod (17), a reversing valve rod (9) between the valve body (1) and the reversing fixed piston (14) is provided with a reversing return spring (13), a cover-closing air port (34) is provided between the reversing fixed piston (14) and the reversing moving piston (15) on the reversing cylinder (12), and an open-cover air port (33) is provided between the reversing moving piston (15) and the reversing cylinder rear cover (16); recessed grooves are respectively provided in the middle of the lifting valve rod (6) and the reversing valve rod (9), and the recessed grooves are respectively connected to oil passages (K);The oil return port 1 (T1) and the oil return port 2 (T2) are interconnected. ; 2. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1 is characterized in that: A vent cover (7) is provided on the valve body (1) at one end of the lift valve stem (6).

3. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1 is characterized in that: An adjusting screw (10) is provided on the adjusting seat (11).

4. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1 is characterized in that: The reversing valve stem (9) is fixedly connected to the reversing return spring (13).

5. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1 is characterized in that: A spare oil port (29) connected to the lifting valve stem (6) is provided on the valve body (1).

6. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1 is characterized in that: A relief valve spring (8) is provided on the secondary pressure relief valve assembly (4).

7. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1 is characterized in that: A sealing ring (3) is provided on the oil return port 1 (T1) and is connected to the oil tank valve seat (35).

8. The dual-path gas-controlled hydraulic reversing valve with different pressures and flows according to claim 1, characterized in that: A diverter valve needle (2) is provided in the oil passage (K).

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