Auxiliary safety hydraulic system for industrial vehicle actuator lock function

Abstract

The application discloses an auxiliary safety hydraulic system for an industrial vehicle actuator locking function, comprising a hydraulic oil pump, a multi-way reversing valve, a rotary motor, an inclination oil cylinder, a lifting oil cylinder, a steering oil cylinder and an oil tank, and realizes the on-off of a steering priority valve and a T port through a two-way unloading valve and a solenoid valve, realizes the inlet pressure cut-off of a lifting valve, an inclination valve and a rotary valve, controls the locking state of the lifting oil cylinder through a lowering oil path setting a lowering locking valve and a solenoid valve, realizes the inclination and rotation maximum flow control through the pressure compensator setting at the inlet of the inclination valve and the rotary valve, realizes the maximum pressure individual control of lifting and other actions through two overflow valves with different spring cavity pressures of the two-way flow valve, realizes the inclination oil cylinder locking and speed fast-slow adjustment through the forward inclination locking valve and the inclination speed regulating valve setting at the inclination oil path, and realizes the safety control of the rotary action through the direction cut-off solenoid valve setting at the rotary oil path.

Description

Technical Field

[0001] This invention relates to the field of hydraulic system technology for industrial vehicles, and in particular to an auxiliary safety hydraulic system with actuator locking function for industrial vehicles. Background Technology

[0002] Industrial vehicle hydraulic systems typically enable hydraulic power steering, lifting, tilting, and attachment rotation. Currently, small-tonnage vehicles generally use manually operated multi-way valves. The speed of the lifting cylinder, tilting cylinder, and motor is achieved solely by moving the position of the multi-way valve stem. Furthermore, even after the oil pump loses power, operating the valve stem can still lower the cylinder.

[0003] The spacing between each valve stem in a multi-way valve is relatively small, which can lead to misoperation of the valve stem. Misoperation of any stem can cause the hydraulic cylinder or motor to move, especially when the vehicle is fully loaded, which can easily lead to safety accidents and poses a safety hazard.

[0004] When loading and unloading goods, industrial vehicles require the driver to operate a valve stem to adjust the forks to a fixed angle. This adjustment is not very precise and often requires repeated adjustments, resulting in low efficiency. When the forks are in a high position, the tilt angle and speed remain the same as when they are in a low position, which can easily cause the vehicle to tip over when fully loaded, posing a safety hazard. Summary of the Invention

[0005] This invention aims to at least partially solve one of the technical problems in the related art. Therefore, one objective of this invention is to provide an auxiliary safety hydraulic system with actuator locking function for industrial vehicles, achieving inlet pressure cutoff of lifting valves, tilting valves, and rotary valves, while each valve stem of a multi-way valve has an actuator locking function.

[0006] An auxiliary safety hydraulic system for industrial vehicles with actuator locking function, according to the present invention, includes a hydraulic pump, a multi-way directional valve with actuator locking function, a rotary motor, a tilting cylinder, a lifting cylinder, a steering cylinder, and an oil tank. The inlet of the hydraulic pump is connected to the inside of the oil tank, and the outlet of the hydraulic pump is connected to the rotary motor, the tilting cylinder, and the lifting cylinder respectively through the multi-way directional valve. The oil tank has a return port, and the rotary motor, the tilting cylinder, and the lifting cylinder are connected to the return port of the oil tank respectively through the multi-way directional valve. The outlet of the hydraulic pump is connected to the steering cylinder in sequence through the multi-way directional valve and the steering controller, and the steering cylinder is connected to the return port of the oil tank in sequence through the steering controller and the multi-way directional valve.

[0007] Preferably, the multi-way directional valve includes a steering priority valve, the inlet of which is connected to the outlet of the hydraulic pump, the CF port of which is connected to the steering cylinder through the steering controller, the steering cylinder through the steering controller and the T port of the multi-way directional valve, and the T port of the multi-way directional valve is connected to the return port of the oil tank.

[0008] Preferably, the multi-way directional valve includes a two-way unloading valve. The EF port of the steering priority valve is connected to the T port of the multi-way directional valve through the two-way unloading valve. The spring chamber of the two-way unloading valve is connected to a third electromagnetic switch valve. When the third electromagnetic switch valve is energized, the two-way unloading valve and the T port of the multi-way directional valve are closed. When the third electromagnetic switch valve is de-energized, the two-way unloading valve and the T port of the multi-way directional valve are connected.

[0009] Preferably, the multi-way directional valve includes a lift valve, the EF port of the steering priority valve is connected to the oil inlet of the lift valve, the oil outlet of the lift valve is connected to the lift cylinder through a descent lock valve, the spring chamber of the descent lock valve is connected to a first electromagnetic switch valve, the oil outlet of the first electromagnetic switch valve is connected to the lift valve, a flow control valve is provided on the pipeline connected to the oil return port of the lift valve, the flow control valve is connected to the T port of the multi-way directional valve, the lift valve has a pressure feedback port a, and the pressure feedback port a of the lift valve is connected to the non-spring chamber of the flow control valve.

[0010] Preferably, the spring chamber of the lowering lock valve is connected to a manual shut-off valve, and the oil outlet of the manual shut-off valve is connected to the T port of the multi-way directional valve.

[0011] Preferably, the multi-way directional valve includes a tilt valve, the EF port of the steering priority valve is connected to the oil inlet of the tilt valve, a tilt pressure compensator is provided on the pipeline connecting the EF port of the steering priority valve and the oil inlet of the tilt valve, the two oil outlets of the tilt valve are respectively connected to the tilt cylinder through a forward tilt locking valve and a tilt speed regulating valve, a forward tilt self-locking valve is provided inside the tilt valve, the oil return port of the tilt valve is connected to the T port of the multi-way directional valve, the tilt valve has a pressure feedback port b, and the pressure feedback port b of the tilt valve is connected to the spring cavity of the tilt pressure compensator.

[0012] Preferably, the multi-way directional valve includes a rotary valve, the EF port of the steering priority valve is connected to the oil inlet of the rotary valve, a rotary pressure compensator is provided on the pipeline connecting the EF port of the steering priority valve and the oil inlet of the rotary valve, the oil outlet of the rotary valve is connected to the rotary motor through a second electromagnetic switch valve, the oil return port of the rotary valve is connected to the T port of the multi-way directional valve, the rotary valve has a pressure feedback port c, and the pressure feedback port c of the rotary valve is connected to the spring cavity of the rotary pressure compensator.

[0013] Preferably, the EF port of the steering priority valve is connected to a two-way flow valve, which is connected to the T port of the multi-way directional valve. The multi-way directional valve includes a lift valve, a tilt valve, and a rotary valve. The lift valve, tilt valve, and rotary valve are respectively provided with pressure feedback ports a, b, and c. The pressure feedback port a of the lift valve is connected to the spring chamber of the two-way flow valve through a first shuttle valve. The pressure feedback ports b and c of the tilt valve and rotary valve are connected to the spring chamber of the two-way flow valve through a second shuttle valve and a first shuttle valve, respectively.

[0014] Preferably, a main relief valve is provided between the spring chamber of the two-way flow valve and the first shuttle valve, and a secondary relief valve is provided between the first shuttle valve and the second shuttle valve.

[0015] Preferably, an oil suction filter is installed at the oil inlet of the hydraulic oil pump, and an oil return filter is installed at the oil return outlet of the oil tank.

[0016] The beneficial effects of this invention are:

[0017] (1) By setting a descent lock-up valve in the lifting valve, the leakage of the lifting cylinder can be reduced;

[0018] (2) By setting a two-way unloading valve in the main oil circuit and setting a third electromagnetic switch valve in the oil return channel of the spring chamber of the two-way unloading valve, the power on and off of the third electromagnetic switch valve controls the cutting off and connection of the steering priority valve EF port and the multi-way reversing valve T port, thereby realizing the lifting lock of the lifting cylinder, the tilting lock of the tilting cylinder and the locking of the rotation position of the rotary motor.

[0019] (3) By setting a first electromagnetic switch valve in the return oil circuit of the spring chamber of the lowering lock valve, the lowering lock valve is forcibly closed by de-energizing the first electromagnetic switch valve, thereby realizing the lowering lock of the lifting cylinder.

[0020] (4) The maximum flow rate during descent is controlled by installing a flow control valve in the descent return oil circuit;

[0021] (5) By setting a forward tilting locking valve in the forward tilting return oil circuit of the tilting cylinder, the forward tilting locking valve includes a check valve and a solenoid valve. The on and off of the oil return oil circuit of the cylinder is controlled by the on and off of the solenoid valve to realize the forward tilting locking of the tilting cylinder. The forward tilting locking valve can also reduce the leakage of the tilting cylinder and achieve zero leakage when used in conjunction with the forward tilting self-locking valve.

[0022] (6) By setting a tilt speed control valve in the tilt cylinder back oil circuit, the tilt speed control valve includes a throttle valve and a solenoid valve. By switching the solenoid valve on and off, the fast and slow tilt speed can be switched, which is beneficial to the stability control of the whole vehicle when the forks are in a high position.

[0023] (7) By setting a second electromagnetic switch valve at the motor inlet, the oil inlet and outlet of the motor are controlled. When the second electromagnetic switch valve is not energized, the oil inlet and outlet of the motor are cut off and cannot rotate. Only when the driver actively energizes the second electromagnetic switch valve can the motor rotate normally, thus playing a safety protection role.

[0024] (8) By installing two relief valves in the spring chamber of the two-way flow valve, the lifting pressure of industrial vehicles is usually the highest, while other actions are much lower than the lifting pressure. One of the two relief valves limits the highest lifting pressure, and the other limits the highest pressure of other circuits, so as to achieve low-pressure unloading during tilting and rotation, and achieve the purpose of energy saving of the system. Attached Figure Description

[0025] In the attached diagram:

[0026] Figure 1 This is a schematic diagram of an auxiliary safety hydraulic system for locking the actuator of an industrial vehicle, as proposed in this invention.

[0027] In the diagram: 1-Suction filter, 2-Hydraulic pump, 3-Return filter, 4-Steering controller, 5-Multi-way directional valve, 6-Rotary motor, 7-Tilting cylinder, 8-Lifting cylinder, 9-Steering cylinder, 10-Oil tank;

[0028] 501-Steering priority valve, 502-Two-way flow valve, 503-Lift valve, 504-First solenoid switch valve, 505-Lowering lock valve, 506-Manual shut-off valve, 507-Tilting valve, 508-Forward tilt self-locking valve, 509-Tilting pressure compensator, 510-Forward tilt lock valve, 511-Tilting speed control valve, 512-Rotary valve, 513-Rotary pressure compensator, 514-Second solenoid switch valve, 515-Two-way unloading valve, 516-Third solenoid switch valve, 517-First shuttle valve, 518-Secondary relief valve, 519-Second shuttle valve, 520-Main relief valve, 521-Flow control valve. Detailed Implementation

[0029] Reference Figure 1An auxiliary safety hydraulic system for industrial vehicles with actuator locking function includes a hydraulic pump 2, a multi-way directional valve 5 with actuator locking function, a rotary motor 6, a tilting cylinder 7, a lifting cylinder 8, a steering cylinder 9, and an oil tank 10. The oil inlet of the hydraulic pump 2 is connected to the inside of the oil tank 10. The oil outlet of the hydraulic pump 2 is connected to the rotary motor 6, the tilting cylinder 7, and the lifting cylinder 8 respectively through the multi-way directional valve 5. The oil tank 10 has a return port. The rotary motor 6, the tilting cylinder 7, and the lifting cylinder 8 are connected to the return port of the oil tank 10 respectively through the multi-way directional valve 5. The oil outlet of the hydraulic pump 2 is connected to the steering cylinder 9 in sequence through the multi-way directional valve 5 and the steering controller 4. The steering cylinder 9 is connected to the return port of the oil tank 10 in sequence through the steering controller 4 and the multi-way directional valve 5.

[0030] The multi-way directional valve 5 includes a steering priority valve 501. The oil inlet of the steering priority valve 501 is connected to the oil outlet of the hydraulic oil pump 2. The CF port of the steering priority valve 501 is connected to the steering cylinder 9 through the steering controller 4. The steering cylinder 9 is connected to the T port of the multi-way directional valve 5 through the steering controller 4. The T port of the multi-way directional valve 5 is connected to the return port of the oil tank 10.

[0031] The multi-way directional valve 5 includes a two-way unloading valve 515. The EF port of the steering priority valve 501 is connected to the T port of the multi-way directional valve 5 through the two-way unloading valve 515. The spring cavity of the two-way unloading valve 515 is connected to a third solenoid switch valve 516. When the third solenoid switch valve 516 is energized, the two-way unloading valve 515 is closed from the T port of the multi-way directional valve 5. When the third solenoid switch valve 516 is de-energized, the two-way unloading valve 515 is connected to the T port of the multi-way directional valve 5.

[0032] The multi-way directional valve 5 includes a lift valve 503. The EF port of the steering priority valve 501 is connected to the oil inlet of the lift valve 503. The oil outlet of the lift valve 503 is connected to the lift cylinder 8 through the descent lock valve 505. The spring chamber of the descent lock valve 505 is connected to a first solenoid switch valve 504. The oil outlet of the first solenoid switch valve 504 is connected to the lift valve 503. The return oil port of the lift valve 503 is connected to a flow control valve 521 on the pipeline. The flow control valve 521 is connected to the T port of the multi-way directional valve 5. The lift valve 503 has a pressure feedback port a, which is connected to the non-spring chamber of the flow control valve 521.

[0033] The spring chamber of the descent lock valve 505 is connected to a manual shut-off valve 506, and the oil outlet of the manual shut-off valve 506 is connected to the T port of the multi-way directional valve 5.

[0034] The multi-way directional valve 5 includes a tilt valve 507. The EF port of the steering priority valve 501 is connected to the oil inlet of the tilt valve 507. A tilt pressure compensator 509 is provided on the pipeline connecting the EF port of the steering priority valve 501 and the oil inlet of the tilt valve 507. The two oil outlets of the tilt valve 507 are connected to the tilt cylinder 7 through the tilt locking valve 510 and the tilt speed regulating valve 511, respectively. A tilt self-locking valve 508 is provided inside the tilt valve 507. The return port of the tilt valve 507 is connected to the T port of the multi-way directional valve 5. The tilt valve 507 has a pressure feedback port b, which is connected to the spring cavity of the tilt pressure compensator 509.

[0035] The multi-way directional valve 5 includes a rotary valve 512. The EF port of the steering priority valve 501 is connected to the oil inlet of the rotary valve 512. A rotary pressure compensator 513 is provided on the pipeline connecting the EF port of the steering priority valve 501 and the oil inlet of the rotary valve 512. The oil outlet of the rotary valve 512 is connected to the rotary motor 6 through the second solenoid switch valve 514. The oil return port of the rotary valve 512 is connected to the T port of the multi-way directional valve 5. The rotary valve 512 has a pressure feedback port c, which is connected to the spring cavity of the rotary pressure compensator 513.

[0036] The EF port of the steering priority valve 501 is connected to a two-way flow valve 502. The two-way flow valve 502 is connected to the T port of the multi-way directional valve 5. The multi-way directional valve 5 includes a lift valve 503, a tilt valve 507, and a rotary valve 512. The lift valve 503, the tilt valve 507, and the rotary valve 512 are respectively provided with pressure feedback ports a, b, and c. The pressure feedback port a of the lift valve 503 is connected to the spring cavity of the two-way flow valve 502 through the first shuttle valve 517. The pressure feedback ports b and c of the tilt valve 507 and the rotary valve 512 are connected to the spring cavity of the two-way flow valve 502 through the second shuttle valve 519 and the first shuttle valve 517, respectively.

[0037] A main relief valve 520 is provided between the spring cavity of the two-way flow valve 502 and the first shuttle valve 517, and a secondary relief valve 518 is provided between the first shuttle valve 517 and the second shuttle valve 519.

[0038] A suction filter 1 is installed at the oil inlet of the hydraulic oil pump 2, and a return oil filter 3 is installed at the oil return port of the oil tank 10.

[0039] The multi-way directional valve 5 is provided with an oil inlet P, which is connected to the oil outlet of the hydraulic oil pump 2. The oil is supplied to the steering controller 4 through the CF port of the steering priority valve 501. The oil outlet of the steering controller 4 is connected to the steering cylinder 9. Excess oil flows to the two-way unloading valve 515 through the EF port of the steering priority valve 501. The oil outlet of the two-way unloading valve 515 is connected to the T port of the multi-way directional valve 5.

[0040] Excess oil can also flow to the two-way flow valve 502 through the EF port of the steering priority valve 501. The oil outlet of the two-way flow valve 502 is connected to the T port of the multi-way directional valve 5.

[0041] Excess oil can flow to the lifting valve 503 through the EF port of the steering priority valve 501, and then enter the lifting cylinder 8 through the lowering lock valve 505. The spring chamber of the lowering lock valve 505 is connected to the first solenoid switch valve 504 and the manual shut-off valve 506 respectively. The oil outlet of the first solenoid switch valve 504 is connected to the lifting valve 503, and the oil outlet of the manual shut-off valve 506 is connected to the T port of the multi-way directional valve 5. The lifting valve 503 is also provided with a pressure feedback port a, and the return oil circuit of the lifting valve 503 is provided with a flow control valve 521.

[0042] Excess oil can also flow to tilt pressure compensator 509 through the EF port of steering priority valve 501. The oil outlet of tilt pressure compensator 509 is connected to tilt valve 507, and then flows into tilt cylinder 7 through tilt lock valve 510 or tilt speed control valve 511 respectively. Tilting valve 507 is equipped with tilt self-locking valve 508 and pressure feedback port b.

[0043] Excess oil can also flow to the rotary pressure compensator 513 through the EF port of the steering priority valve 501. The oil outlet of the rotary pressure compensator 513 is connected to the rotary valve 512. The oil flows to the rotary motor 6 through the A3 and B3 ports of the rotary valve 512. The A3 port is equipped with a directional shut-off solenoid valve 514. The rotary valve 512 is also equipped with a pressure feedback port c.

[0044] Pressure feedback ports b and c are connected to the first shuttle valve 517, and pressure feedback ports a and b are connected to the second shuttle valve 519. The oil outlet of the second shuttle valve 519 is connected to the spring cavity of the two-way flow valve 502. The spring cavity of the two-way flow valve 502 is equipped with a main relief valve 520. The oil outlet of the first shuttle valve 517 is also connected to the secondary relief valve 518. The T port of the multi-way directional valve is connected to the oil tank 10 through the return oil filter 3.

[0045] When the vehicle is in motion, the hydraulic oil pump 2 outlet oil first enters the steering priority valve 501 through the multi-way directional valve 5 port P. Due to the CF port of the steering controller 4 being closed, under the action of the pressure difference △P1 on the steering priority valve 501, the valve core of the steering priority valve 501 moves upward. The oil at the LS port flows to the T port of the multi-way directional valve 5 through the T1 port of the steering controller 4. The oil at the P port flows to the two-way unloading valve 515 through the EF port. When the solenoid valve 516 is de-energized, there is no pressure in the spring chamber of the two-way unloading valve 515. A large amount of oil enters the upper chamber of the two-way unloading valve 515, pushing the valve core downward. All the oil at the EF port returns to the oil tank 10. At this time, the pressure at the EF port is almost zero.

[0046] When the vehicle needs to turn, the P1 port of the steering controller 4 is connected to the L or R port of the steering cylinder 9, the Ls port of the multi-way directional valve 5 is disconnected from the T1 port of the steering gear and connected to the P1 port of the steering controller 4. At this time, the pressure of the steering cylinder 9 is transmitted to the spring chamber of the steering priority valve 501 through the LS port, pushing the valve core of the steering priority valve 501 to move downward. The steering priority valve 501 supplies oil to the steering controller 4 to complete the vehicle steering.

[0047] When the third solenoid valve 516 is de-energized, the pressure at port EF is essentially zero, so the entire hydraulic system can only perform steering actions. The driver can only control the vehicle's direction and cannot lift, tilt, or rotate. Only when the third solenoid valve 516 is energized does the spring chamber of the two-way unloading valve 515 disconnect from the T port of the multi-way directional valve 5. At this time, the pressure at both ends of the two-way unloading valve 515 is equal. Under the action of the spring force, the valve core moves upward, and port EF disconnects from port T of the multi-way directional valve 5. When the lifting valve 503, tilting valve 507, and rotating valve 512 are not activated, the oil at port EF flows to the two-way flow valve 502. The spring chamber of the two-way flow valve 502 is connected to port T of the multi-way directional valve 5 through port a of the lifting valve 503. Under the action of the pressure in the left chamber of the two-way flow valve 502, the valve core moves to the right, and the oil at port EF returns to the oil tank 10 through port T of the multi-way directional valve 5.

[0048] When the lifting valve 503 is in its initial position, the oil in the lifting cylinder 8 quickly enters the spring chamber of the lowering lock valve 505, and the valve core moves upward to close the return oil passage of the lifting cylinder 8, thus completely locking the lifting cylinder 8. When the lifting valve 503 moves upward, the oil at port EF enters the spring chamber of the two-way flow valve 502 through the pressure feedback port a. At this time, the pressure in the left and right chambers of the two-way flow valve 502 is equal. Under the action of the spring force, the valve core moves to the left, and port EF disconnects from port T of the multi-way directional valve 5. All the oil at port EF flows to the lifting valve 503. Under the action of pressure, the lowering lock valve 505 moves downward, and the oil outlet of the lifting valve 503 connects with the lifting cylinder 8, realizing the lifting of the gantry. When the lifting valve 503 moves downward, if the solenoid valve 504 is de-energized, the lowering lock valve 505... When the spring chamber of 05 is filled with oil and cannot move, the lifting cylinder 8 cannot move. Only when the first solenoid valve 504 is energized, the spring chamber of the lowering locking valve 505 is connected to the T port of the multi-way directional valve 5 through the first solenoid valve 504. Under the action of the cylinder bottom pressure, the valve core of the lowering locking valve 505 moves downward, and the lifting cylinder 8 is connected to the flow control valve 521 through the lifting valve 503. At this time, the pressure in the left chamber of the flow control valve 521 is equal to the pressure in the right chamber, the valve core moves to the left, and the flow control valve 521 is connected to the T port of the multi-way directional valve 5 to realize the cylinder descent. If the first solenoid valve 504 cannot switch normally due to an accident, the cylinder descent can also be realized by releasing the manual shut-off valve 506 to connect the spring chamber of the lowering locking valve 505 to the T port of the multi-way directional valve 5.

[0049] When the tilt valve 507 moves upward from its original position, the oil at port EF enters the spring chamber of the two-way flow valve 502 through the pressure feedback port b, disconnecting port EF from port T of the multi-way directional valve 5. All the oil at port EF flows to the tilt valve 507. When the tilt locking valve 510 is de-energized, the right chamber of the tilt cylinder 7 is disconnected from the tilt valve 507, and the tilting action cannot be achieved. Only when the tilt locking valve 510 is energized, the valve core moves to the left, and the pressure oil in the right chamber of the tilt cylinder 7 acts on the tilt self-locking valve 508. The oil enters the left chamber of the tilt cylinder 7 through the tilt speed regulating valve 511, pushing the cylinder to the right and simultaneously pushing the tilt self-locking valve 508 to move upward. The right chamber of the tilt cylinder 7 is connected to port T of the multi-way directional valve 5, achieving the tilting action. At this time, when the tilt speed regulating valve 511 is energized, the valve core moves to the right, the flow area of ​​the tilt speed regulating valve 511 reaches its maximum, the oil intake of the left chamber of the tilt cylinder 7 increases, and rapid tilting is achieved.

[0050] When the tilt valve 507 moves downward from its original position, the oil at port EF enters the spring chamber of the two-way flow valve 502 through the pressure feedback port b, disconnecting the T port of the multi-way directional valve 5 at port EF. All the oil at port EF flows to the tilt valve 507 and then to the right chamber of the tilt cylinder 7 through the check valve in the tilt locking valve 510. The oil in the left chamber returns to the oil tank 10 at the fastest speed through the tilt speed regulating valve 511. If the solenoid valve of the tilt speed regulating valve 511 is de-energized at this time, the oil can only return to the oil tank slowly through the throttle orifice of the tilt speed regulating valve 511.

[0051] When the rotary valve 512 moves upward from its original position, the oil at port EF enters the spring chamber of the two-way flow valve 502 through the pressure feedback port c, disconnecting port EF from port T of the multi-way directional valve 5. All the oil at port EF flows to the rotary valve 512 and into the rotary motor 6 from port B3. If the second solenoid valve 514 is de-energized at this time, the return port A3 is closed, and the rotary motor 6 cannot rotate. Only when the second solenoid valve 514 is energized will the valve core move to the left, and port A3 will connect with port T of the multi-way directional valve 5, causing the rotary motor 6 to start rotating to the left.

[0052] When the rotary valve 512 moves downward from its original position, the oil at port EF enters the spring chamber of the two-way flow valve 502 through the pressure feedback port c, disconnecting port EF from port T of the multi-way valve. All the oil at port EF flows to the rotary valve 512. If the second solenoid switch valve 514 is de-energized at this time, port A3 is closed, and the oil cannot flow into the rotary motor 6, so the rotary motor 6 cannot rotate. Only when the second solenoid switch valve 514 is energized will the valve core move to the left, connecting the rotary valve 512 with port A3, and the rotary motor 6 will start to rotate to the right.

[0053] The pressure in the left chamber of the two-way flow valve 502 is equal to the pressure at port EF. The pressure in the spring chamber comes from feedback ports a, b, and c. The pressure difference between the left chamber and the spring chamber is the spring force. Thus, the pressure difference between the inlet and outlet of the lift valve 503, tilt valve 507, and rotary valve 512 is approximately constant at ΔP2, allowing for precise control of the valve flow rate. Similarly, a tilt pressure compensator 509 is separately installed at the inlet of the tilt valve 507 to control the valve flow rate. The spring force of the tilt pressure compensator 509 is adjustable; by adjusting the spring force, the maximum flow rate at the inlet of the tilt valve 507 can be limited. The rotary valve 512 is equipped with a similar rotary pressure compensator 513.

[0054] With all solenoid valves de-energized, the system can only perform steering actions; other actions are impossible. The lifting cylinder 8, tilting cylinder 7, and rotary motor 6 are completely locked, and the vehicle mast is stationary. Only when the driver confirms the vehicle is in normal condition and the surrounding environment is safe, and actively energizes the third solenoid valve 516, can the system perform lifting and tilting actions, serving as a safety warning. Only when the first solenoid valve 504 is actively energized can the mast lower. De-energizing the first solenoid valve 504 immediately locks the lifting cylinder 8, preventing it from becoming uncontrollable in case of an accident.

[0055] The gantry can only tilt forward when the forward tilting locking valve 510 is actively energized. After the power is cut off, the tilting cylinder 7 automatically locks, which plays a safety protection role. At the same time, in the stationary state, the forward tilting locking valve 510 can also improve the sealing performance of the tilting cylinder 7 and reduce the automatic tilting angle of the gantry.

[0056] By switching the tilt speed control valve 511 on and off, the tilting speed can be switched between fast and slow, allowing the gantry to tilt quickly at low cargo positions and slowly at high cargo positions, preventing the vehicle from tipping over and improving the overall vehicle safety performance.

[0057] Only when the second electromagnetic switch valve 514 is actively energized can the rotary motor 6 rotate normally, preventing the rotary motor 6 from rotating when the rotary valve 512 is misoperated, thus playing a safety protection role.

[0058] In addition, the solenoid valve can be used in conjunction with the actuator position sensor to set the height and angle of the forks when the vehicle is working. Once the set position is reached, the solenoid valve will automatically cut off the power, thus achieving efficient cargo handling.

[0059] The pressure at feedback port a passes through the second shuttle valve 519 and enters the oil inlet of the main relief valve 520. If the pressure at port a exceeds the set pressure, the system overflows, protecting system components from high-pressure surges. Similarly, the pressures at feedback ports b and c pass through the first shuttle valve 517 and enter the oil inlets of the main relief valve 520 and the secondary relief valve 518. The pressure at the secondary relief valve 518 is lower than that at the main relief valve 520, enabling tilting and rotating low-pressure overflow, thus reducing system energy consumption.

Claims

1. An auxiliary safety hydraulic system for locking actuators in industrial vehicles, characterized in that: The system includes a hydraulic pump (2), a multi-way directional valve (5) with actuator locking function, a rotary motor (6), a tilting cylinder (7), a lifting cylinder (8), a steering cylinder (9), and an oil tank (10). The inlet of the hydraulic pump (2) is connected to the inside of the oil tank (10), and the outlet of the hydraulic pump (2) is connected to the rotary motor (6), the tilting cylinder (7), and the lifting cylinder (8) respectively through the multi-way directional valve (5). The oil tank (10) is connected to the oil tank (10). 0) An oil return port is provided. The rotary motor (6), the tilting cylinder (7) and the lifting cylinder (8) are respectively connected to the oil return port of the oil tank (10) through the multi-way reversing valve (5). The oil outlet of the hydraulic pump (2) is connected to the steering cylinder (9) in sequence through the multi-way reversing valve (5) and the steering controller (4). The steering cylinder (9) is connected to the oil return port of the oil tank (10) in sequence through the steering controller (4) and the multi-way reversing valve (5). The multi-way directional valve (5) includes a steering priority valve (501). The oil inlet of the steering priority valve (501) is connected to the oil outlet of the hydraulic oil pump (2). The CF port of the steering priority valve (501) is connected to the steering cylinder (9) through the steering controller (4). The steering cylinder (9) is connected to the T port of the multi-way directional valve (5) through the steering controller (4). The T port of the multi-way directional valve (5) is connected to the return port of the oil tank (10). The multi-way directional valve (5) includes a two-way unloading valve (515). The EF port of the steering priority valve (501) is connected to the T port of the multi-way directional valve (5) through the two-way unloading valve (515). The spring cavity of the two-way unloading valve (515) is connected to a third electromagnetic switch valve (516). When the third electromagnetic switch valve (516) is energized, the two-way unloading valve (515) is closed from the T port of the multi-way directional valve (5). When the third electromagnetic switch valve (516) is de-energized, the two-way unloading valve (515) is connected to the T port of the multi-way directional valve (5). The steering priority valve (501) has a two-way flow valve (502) connected to its EF port. The two-way flow valve (502) is connected to the T port of the multi-way directional valve (5). The multi-way directional valve (5) includes a lift valve (503), a tilt valve (507), and a rotary valve (512). The lift valve (503), tilt valve (507), and rotary valve (512) are respectively provided with pressure feedback ports a, b, and c. The pressure feedback port a of the lift valve (503) is connected to the spring cavity of the two-way flow valve (502) through the first shuttle valve (517). The pressure feedback ports b and c of the tilt valve (507) and rotary valve (512) are connected to the spring cavity of the two-way flow valve (502) through the second shuttle valve (519) and the first shuttle valve (517) respectively.

2. The auxiliary safety hydraulic system for locking the actuator of an industrial vehicle according to claim 1, characterized in that: The multi-way directional valve (5) includes a lift valve (503). The EF port of the steering priority valve (501) is connected to the oil inlet of the lift valve (503). The oil outlet of the lift valve (503) is connected to the lift cylinder (8) through a descent lock valve (505). The spring chamber of the descent lock valve (505) is connected to a first electromagnetic switch valve (504). The oil outlet of the first electromagnetic switch valve (504) is connected to the lift valve (503). A flow control valve (521) is provided on the pipeline connected to the return port of the lift valve (503). The flow control valve (521) is connected to the T port of the multi-way directional valve (5). The lift valve (503) has a pressure feedback port a. The pressure feedback port a of the lift valve (503) is connected to the non-spring chamber of the flow control valve (521).

3. The auxiliary safety hydraulic system for locking the actuator of an industrial vehicle according to claim 1, characterized in that: The spring chamber of the descent locking valve (505) is connected to a manual shut-off valve (506), and the oil outlet of the manual shut-off valve (506) is connected to the T port of the multi-way directional valve (5).

4. The auxiliary safety hydraulic system for locking the actuator of an industrial vehicle according to claim 1, characterized in that: The multi-way directional valve (5) includes a tilt valve (507). The EF port of the steering priority valve (501) is connected to the oil inlet of the tilt valve (507). A tilt pressure compensator (509) is provided on the pipeline connecting the EF port of the steering priority valve (501) and the oil inlet of the tilt valve (507). The two oil outlets of the tilt valve (507) are connected to the tilt cylinder (7) through a forward tilt locking valve (510) and a tilt speed regulating valve (511), respectively. A forward tilt self-locking valve (508) is provided inside the tilt valve (507). The return port of the tilt valve (507) is connected to the T port of the multi-way directional valve (5). The tilt valve (507) has a pressure feedback port b. The pressure feedback port b of the tilt valve (507) is connected to the spring cavity of the tilt pressure compensator (509).

5. The auxiliary safety hydraulic system for locking the actuator of an industrial vehicle according to claim 1, characterized in that: The multi-way directional valve (5) includes a rotary valve (512). The EF port of the steering priority valve (501) is connected to the oil inlet of the rotary valve (512). A rotary pressure compensator (513) is provided on the pipeline connecting the EF port of the steering priority valve (501) and the oil inlet of the rotary valve (512). The oil outlet of the rotary valve (512) is connected to the rotary motor (6) through a second electromagnetic switch valve (514). The oil return port of the rotary valve (512) is connected to the T port of the multi-way directional valve (5). The rotary valve (512) has a pressure feedback port c. The pressure feedback port c of the rotary valve (512) is connected to the spring cavity of the rotary pressure compensator (513).

6. The auxiliary safety hydraulic system for locking the actuator of an industrial vehicle according to claim 1, characterized in that: A main relief valve (520) is provided between the spring cavity of the two-way flow valve (502) and the first shuttle valve (517), and a secondary relief valve (518) is provided between the first shuttle valve (517) and the second shuttle valve (519).

7. The auxiliary safety hydraulic system for locking the actuator of an industrial vehicle according to claim 1, characterized in that: The hydraulic pump (2) is equipped with a suction filter (1) at the inlet and a return filter (3) is equipped with a return port of the oil tank (10).

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