Hydraulic system for double piling cars

Abstract

The hydraulic system comprises a first stacking hydraulic cylinder set and a second stacking hydraulic cylinder set, and the first stacking hydraulic cylinder set and the second stacking hydraulic cylinder set are connected with an oil supply pipeline through a control valve block assembly to be communicated. The control valve block assembly comprises an oil inlet pipeline and an oil return pipeline, the oil inlet pipeline is connected with the oil supply pipeline, the oil inlet pipeline is communicated with the first stacking hydraulic cylinder set and the second stacking hydraulic cylinder set through a first oil inlet branch pipe and a second oil inlet branch pipe respectively, and the first oil inlet branch pipe and the second oil inlet branch pipe are each provided with an electromagnetic valve. The oil return pipeline comprises a first oil return channel and a second oil return channel which are communicated with the first oil inlet branch pipe and the second oil inlet branch pipe, and electromagnetic valves are arranged on the first oil return channel and the second oil return channel. By the adoption of the double-loop design, independent operation can be achieved, combined operation can also be achieved, mutual interference is avoided, double stacking is achieved, and the oil return efficiency is improved. And two trays can be stacked at a time, so that the working efficiency is doubled.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, in particular to a hydraulic system for a double stacker. Background Art

[0002] Traditional stacking forklift hydraulic systems generally only have one stacking function. With the continuous development of science and technology, these functions can no longer meet people's requirements, such as low work efficiency, large stacking impact, and inability to achieve effective control of the hydraulic system. How to solve these problems based on the hydraulic system of traditional stacking forklifts has become a major problem for the hydraulic system of stacking forklifts. Summary of the Invention

[0003] The object of the present invention is to provide a hydraulic system for a double stacker to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solutions:

[0005] A double stacker hydraulic system comprises a first stacking hydraulic cylinder group and a second stacking hydraulic cylinder group, wherein the first stacking hydraulic cylinder group and the second stacking hydraulic cylinder group are connected to an oil supply pipeline via a control valve block assembly;

[0006] The control valve block assembly includes an oil inlet pipeline and an oil return pipeline. The oil inlet pipeline is connected to the oil supply pipeline. The oil inlet pipeline is connected to the first stacked hydraulic cylinder group and the second stacked hydraulic cylinder group through the first oil inlet branch pipe and the second oil inlet branch pipe respectively. The first oil inlet branch pipe and the second oil inlet branch pipe are both provided with solenoid valves. The oil return pipeline includes a first return oil channel and a second return oil channel connected to the first oil inlet branch pipe and the second oil inlet branch pipe. The first return oil channel and the second return oil channel are both provided with solenoid valves.

[0007] As a further solution of the present invention: the oil supply pipeline includes a hydraulic oil tank and a gear pump, and the oil inlet pipeline is connected to the hydraulic oil tank through the gear pump.

[0008] As a further solution of the present invention: the gear pump is connected to a motor for driving the gear pump, and the motor is provided with a motor temperature sensor.

[0009] As a further solution of the present invention: an oil suction filter is provided at the oil inlet end of the gear pump, and a hydraulic oil temperature sensor is provided at the oil outlet end of the gear pump.

[0010] As a further solution of the present invention: a one-way valve is provided on the oil inlet pipeline, the oil outlet end of the one-way valve is connected to the first oil inlet branch pipe and the second oil inlet branch pipe, and the oil inlet end of the one-way valve is connected to the return oil pipeline through a relief valve.

[0011] As a further solution of the present invention: a first solenoid valve is provided on the first oil inlet branch pipe, the first stacking hydraulic cylinder group includes a first stacking left cylinder and a first stacking right cylinder, the first stacking left cylinder and the first stacking right cylinder are connected to the first oil inlet branch pipe through a first tee, the oil outlet end of the first oil inlet branch pipe is provided with a first pressure sensor and an explosion-proof valve, and the first stacking left cylinder and / or the first stacking right cylinder are provided with a displacement sensor and a first photoelectric switch.

[0012] As a further solution of the present invention: a second solenoid valve is provided on the second oil inlet branch pipe, the second stacking hydraulic cylinder group includes a second stacking left cylinder and a second stacking right cylinder, the second stacking left cylinder and the second stacking right cylinder are connected to the second oil inlet branch pipe through a second T-joint, a second pressure sensor is provided on the second oil inlet branch pipe, and a second photoelectric switch is provided on the second stacking left cylinder and / or the second stacking right cylinder.

[0013] As a further solution of the present invention: a third solenoid valve and a first flow compensation valve are provided on the first return oil channel, and a first emergency switch valve is connected in parallel on the bypass of the third solenoid valve and the first flow compensation valve; a fourth solenoid valve and a second flow compensation valve are provided on the second return oil channel, and a second emergency switch valve is connected in parallel on the bypass of the fourth solenoid valve and the second flow compensation valve.

[0014] As a further solution of the present invention: the first oil return channel and the second oil return channel are connected to the hydraulic oil tank through an oil return main pipe, a radiator is provided on the oil return main pipe, a fan is provided on one side of the radiator, a bypass valve is connected in parallel to the radiator, the bypass valve is connected to the oil inlet and oil outlet of the radiator through a third three-way valve and a fourth three-way valve, a return oil filter is provided at the oil outlet of the oil return main pipe, and a bypass check valve is provided on the return oil filter.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The dual-circuit design adopted in this application can not only realize independent operation, but also realize joint operation without mutual interference, realize double stacking, and can stack two pallets at a time, doubling the work efficiency;

[0017] 2. This application has an overload protection function, which improves the safety performance during the stacking process;

[0018] 3. This application also has a system heat dissipation device that can dissipate the return oil and control the oil temperature of the hydraulic system to avoid excessive oil temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a schematic diagram of the hydraulic control system of this embodiment;

[0020] Figure 2 This is the front view of the control valve block assembly of this embodiment;

[0021] Figure 3 This is a left side view of the control valve block assembly of this embodiment;

[0022] Figure 4 This is a bottom view of the control valve block assembly of this embodiment;

[0023] Figure 5 This is a left side view of the control valve block assembly of this embodiment;

[0024] Figure 6 This is a top view of the control valve block assembly of this embodiment; Figure 7 for Figure 4 CC cross-sectional view;

[0025] Figure 8 Figure 4 DD cross-sectional view;

[0026] Figure 9 This is an axial side view of the control valve block assembly of this embodiment;

[0027] In the figure: 1- hydraulic oil tank, 2- oil return filter, 2.1- bypass check valve, 3- radiator, 4- bypass valve, 5- control valve block assembly, 5.1- second emergency switch valve, 5.2- second flow compensation valve, 5.3- fourth solenoid valve, 5.4- first pressure sensor, 5.5- second pressure sensor, 5.6- second solenoid valve, 5.7- first solenoid valve, 5.8- third solenoid valve, 5.9- first flow compensation valve, 5.10- check valve, 5.11- overflow valve, 5.12- first emergency switch valve, 5 .13-First oil return channel, 5.14-Second oil return channel, 7-Displacement sensor, 8-First stack left cylinder, 9-First stack right cylinder, 10-Second stack left cylinder, 11-Second stack right cylinder, 12-Explosion-proof valve, 13-First three-way valve, 14-Second three-way valve, 15-Motor temperature sensor, 16-Motor, 17-Gear pump, 18-Oil suction filter, 19-Hydraulic oil temperature sensor, 20-Fan, 21-Third three-way valve, 22-Fourth three-way valve, 23-First photoelectric switch, 24-Second photoelectric switch. DETAILED DESCRIPTION

[0028] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] See also Figure 1-9 In an embodiment of the present invention, a double stacker hydraulic system includes a first stacking hydraulic cylinder group and a second stacking hydraulic cylinder group. The first stacking hydraulic cylinder group and the second stacking hydraulic cylinder group are connected to an oil supply pipeline through a control valve block assembly 5.

[0030] The oil supply pipeline includes a hydraulic oil tank 1 and a gear pump 17. The oil inlet pipeline is connected to the hydraulic oil tank 1 through the gear pump 17. The gear pump 17 is connected to a motor 16 for driving the gear pump 17. A motor temperature sensor 15 is provided on the motor 16. An oil suction filter 18 is provided at the oil inlet end of the gear pump 17, and a hydraulic oil temperature sensor 19 is provided at the oil outlet end of the gear pump 17.

[0031] The control valve block assembly 5 includes an oil inlet line and an oil return line. A check valve 5.10 is installed on the oil inlet line. The oil outlet of the check valve 5.10 is connected to the first and second oil inlet branches. The oil inlet of the check valve 5.10 is connected to the oil return line via a relief valve 5.11. The oil inlet line is connected to the first and second stack hydraulic cylinder groups through the first and second oil inlet branches, respectively. The first stack hydraulic cylinder group includes the first stack left cylinder 8 and the first stack right cylinder 9. The second stack hydraulic cylinder group includes the second stack left cylinder 10 and the second stack right cylinder 11.

[0032] The first oil inlet branch pipe and the second oil inlet branch pipe are both provided with solenoid valves. The return oil pipeline includes a first oil return oil channel 5.13 and a second oil return oil channel 5.14 connected to the first oil inlet branch pipe and the second oil inlet branch pipe. The first oil return oil channel 5.13 and the second oil return oil channel 5.14 are both provided with solenoid valves.

[0033] In this embodiment, a first solenoid valve 5.7 is provided on the first oil inlet branch pipe, and the first solenoid valve 5.7 is a two-position, two-way, two-way shut-off solenoid valve. The left cylinder 8 of the first stack and the right cylinder 9 of the first stack are connected to the first oil inlet branch pipe via a first three-way valve 13. The oil outlet end of the first oil inlet branch pipe is provided with a first pressure sensor 5.4 and an explosion-proof valve 12. The left cylinder 8 of the first stack and / or the right cylinder 9 of the first stack are provided with a displacement sensor 7 and a first photoelectric switch 23. A second solenoid valve 5.6 is provided on the second oil inlet branch pipe, and the second solenoid valve 5.6 is a two-position, two-way, two-way shut-off solenoid valve. The left cylinder 10 of the second stack and the right cylinder 11 of the second stack are connected to the second oil inlet branch pipe via a second three-way valve 14. A second pressure sensor 5.5 is provided on the second oil inlet branch pipe, and a second photoelectric switch is provided on the left cylinder 10 of the second stack and / or the right cylinder 11 of the second stack.

[0034] The first oil return passage 5.13 is equipped with a third solenoid valve 5.8 and a first flow compensation valve 5.9. A first emergency on-off valve 5.12 is connected in parallel to the bypass circuit between the third and first flow compensation valves 5.8 and 5.9. The second oil return passage 5.14 is equipped with a fourth solenoid valve 5.3 and a second flow compensation valve 5.2. A second emergency on-off valve 5.1 is connected in parallel to the bypass circuit between the fourth and second flow compensation valves 5.3 and 5.2. Both the third and fourth solenoid valves 5.8 and 5.3 are two-position, two-way solenoid proportional valves.

[0035] The first and second oil return passages 5.13 and 5.14 are connected to the hydraulic oil tank 1 via an oil return main pipe. A radiator 3 is provided on the oil return main pipe. A fan 20 is provided on one side of the radiator 3. A bypass valve 4 is connected in parallel to the radiator 3. The bypass valve 4 is connected to the oil inlet and outlet of the radiator 3 via a third three-way valve 21 and a fourth three-way valve 22. A return oil filter 2 is provided at the oil outlet of the oil return main pipe, and a bypass check valve 2.1 is provided on the return oil filter 2.

[0036] When the present invention is in use, it includes the first stacking lifting and lowering process, the second stacking lifting and lowering process, and the first stacking and the second stacking working process at the same time, which are specifically as follows:

[0037] The first stack lifting and lowering process:

[0038] The first solenoid valve 5.7 is energized and switches to the left position. At the same time, the motor 16 starts and drives the gear pump 17 to work. The oil flows from the hydraulic oil tank 1 through the oil suction filter 18 into the gear pump 17 and reaches the oil inlet P of the control valve block assembly 5. Then, it passes through the one-way valve 5.10, switches the solenoid valve to the left position, passes through the oil port A of the control valve block assembly 5, passes through the first three-way valve 13, and passes through the explosion-proof valve 12 to the rodless chambers of the left cylinder 8 and the right cylinder 9 of the first stack respectively. Under the action of oil pressure, the piston rods of the left cylinder 8 and the right cylinder 9 of the first stack are pushed upward, completing the lifting action of the first stack.

[0039] The oil pressure value of the first pressure sensor 5.4 is detected in real time. When the pressure value exceeds the preset pressure value, the speed of the control motor 16 is reduced to the preset speed, and the speed of the gear pump 17 is also reduced accordingly. The output flow rate of the gear pump 17 is reduced, thereby controlling the lifting speed of the first stack with heavy and light loads. Simultaneously, the displacement height value of the displacement sensor 7 installed on the left oil cylinder 8 of the first stack is detected in real time. When the lifting height exceeds the preset height value, the speed of the control motor 16 is reduced to the preset speed, and the speed of the gear pump 17 is also reduced accordingly. The output flow rate of the gear pump 17 is reduced, and the lifting speed of the first stack is reduced, thereby controlling the stacking speed of the first stack height. The position of the first photoelectric switch 23 is detected in real time. When the first stack is about to reach the top, the speed of the control motor 16 is ramped down, and the output flow rate of the gear pump 17 is ramped down. The lifting speed is gradually reduced, thereby achieving buffer control of the first stack reaching the top.

[0040] When the system reaches the top, the oil pressure exceeds the pressure of relief valve 5.11, causing it to open. The oil flows through the return port T of the control valve block assembly 5, through the third tee 21, into the radiator 3, and through the fourth tee 22 into the return filter 2, ultimately returning to the hydraulic tank 1, completing overload protection. If the radiator 3 becomes clogged and the oil pressure exceeds the pressure of the bypass check valve 4, the bypass check valve 4 opens, allowing the oil to flow through the third tee 22 and return filter 2 back to the hydraulic tank 1. If the oil pressure in the return filter 2 exceeds the pressure of the bypass check valve 2.1, the bypass check valve 2.1 opens, allowing the oil to flow back to the hydraulic tank 1.

[0041] When first solenoid valve 5.7 loses power, motor 16 stops, gear pump 17 stops, and the oil circuit is disconnected, the third solenoid valve becomes energized and shifts to the right position. The left and right cylinders 8 and 9 of the first stack descend under gravity, pushing the oil in the rodless chamber through explosion-proof valve 12, through the first tee 13, and into port A of the control valve block assembly 5. The oil flows through the first return oil passage 5.13, into the right position of the third solenoid valve 5.8, passes through the right position of the first flow compensation valve 5.9, and through the return oil port T. It flows through the third tee 21 into the radiator 3, through the third tee 22 into the return oil filter 2, and then back to the hydraulic tank 1, completing the first stack's descent. If descent is impossible due to a malfunction of third solenoid valve 5.8 or an electrical fault, the emergency on / off valve 5.12 can be opened to complete the descent.

[0042] Real-time detection of the oil pressure value of the first pressure sensor 5.4, when the pressure value exceeds the preset pressure value,

[0043] The current and opening size of the third solenoid valve 5.8 are controlled to control the descent speed of the first stack. The position of the first photoelectric switch 23 is monitored in real time. When the first stack is about to bottom out, the current ramp of the third solenoid valve 5.8 is reduced, gradually reducing the opening size and the descent speed, thus buffering the descent speed of the first stack.

[0044] When radiator 3 is clogged and the oil pressure exceeds the pressure value of bypass check valve 4, bypass check valve 4 opens and flows back to hydraulic oil tank 1 through tee 22 and return oil filter 2. When the oil pressure exceeds the pressure value of bypass check valve 2.1 in the return oil filter 2, bypass check valve 2.1 opens and flows back to hydraulic oil tank 1.

[0045] The second stack lifting and lowering process:

[0046] When the second solenoid valve 5.6 is energized, the second solenoid valve 5.6 is switched to the left position. At the same time, the motor 16 is started to drive the gear pump 17 to work. The oil flows from the hydraulic oil tank 1 through the oil suction filter 18 into the gear pump 17 to the oil inlet P of the control valve block assembly 5, passes through the one-way valve 5.10, enters the left position of the second solenoid valve 5.6, passes through the oil port B of the control valve block assembly 5, passes through the second three-way valve 14, and enters the rodless chambers of the left cylinder 10 and the right cylinder 11 of the second stack respectively. Under the action of oil pressure, the piston rods of the left cylinder 10 and the right cylinder 11 of the second stack are pushed upward, completing the lifting action of the second stack.

[0047] The oil pressure value of the second pressure sensor 5.5 is detected in real time. When the pressure value exceeds a preset pressure value, the speed of the control motor 16 is reduced to a preset speed, and the speed of the gear pump 17 is also reduced accordingly. The output flow rate of the gear pump 17 is reduced to achieve the control of the lifting speed of the second stack with heavy and light loads. The position of the second photoelectric switch 24 is detected in real time. When the second stack is about to be lifted to the top, the speed of the control motor 16 is ramped down, the output flow rate of the gear pump 17 is ramped down, and the lifting speed is gradually reduced to achieve the buffer control of the lifting of the first stack to the top.

[0048] If the system oil pressure exceeds the pressure of relief valve 5.11, relief valve 5.11 opens, flows through the return port T of control valve block assembly 5, through the third tee 21, into radiator 3, through the fourth tee 22, into return filter 2, and back into hydraulic tank 1, completing overload protection. If radiator 3 is clogged and the oil pressure exceeds the pressure of bypass check valve 4, bypass check valve 4 opens, and the oil flows through the third tee 22 and return filter 2 back into hydraulic tank 1. If the oil pressure in the return filter 2 exceeds the pressure of bypass check valve 2.1, bypass check valve 2.1 opens, and the oil flows back into hydraulic tank 1.

[0049] When the second solenoid valve 5.6 loses power, the motor 16 stops, the gear pump 17 stops, and the stack is switched to the right position, disconnecting the oil circuit in both directions. The fourth solenoid valve 5.3 then becomes energized and switches to the right position. The left cylinder 10 and the right cylinder 11 of the second stack descend under the action of gravity, pushing the oil in the rodless chamber through the second tee 14 and into port B of the control valve block assembly 5. The oil flows through the second return oil passage 5.14, enters the right position of the second solenoid valve 5.3, passes through the right position of the second flow compensation valve 5.2, flows through the return oil port T, flows through the third tee 21 to the radiator 3, flows through the fourth tee 22 to the return oil filter 2, and returns to the hydraulic tank 1, completing the lowering of the second stack. If the stack cannot be lowered due to a malfunction of the fourth solenoid valve 5.3 or an electrical fault, the emergency on / off valve 5.1 can be opened to complete the lowering.

[0050] The oil pressure value of the second pressure sensor 5.5 is detected in real time. When the pressure value exceeds the preset pressure value, the current of the fourth solenoid valve 5.3 is controlled, and the opening size of the fourth solenoid valve 5.3 is controlled to achieve the descent speed control of the second stack. The position of the second photoelectric switch 24 is detected in real time. When the second stack is about to reach the bottom, the current ramp of the fourth solenoid valve 5.3 is controlled to decrease, and the opening of the fourth solenoid valve 5.3 is controlled to gradually decrease, and the descent speed of the second stack is gradually reduced.

[0051] When radiator 3 is clogged and the oil pressure exceeds the pressure value of bypass check valve 4, bypass check valve 4 opens and flows back to hydraulic oil tank 1 through tee 22 and return oil filter 2. When the oil pressure exceeds the pressure value of bypass check valve 2.1 in the return oil filter 2, bypass check valve 2.1 opens and flows back to hydraulic oil tank 1.

[0052] The first and second stacks are lifted simultaneously:

[0053] When both the first and second solenoid valves 5.7 and 5.6 are energized, the motor 16 starts and drives the gear pump 17 to operate. Oil flows from the hydraulic tank 1 through the oil suction filter 18, enters the gear pump 17, and reaches the oil inlet P of the control valve block assembly 5. Then, it passes through the one-way valve 5.10 and, in the working order, enters the left positions of the first and second solenoid valves 5.7 and 5.6 respectively. Then, it passes through the oil ports A and B of the control valve block assembly 5, passes through the first three-way valve 13, the second three-way valve 14, and the explosion-proof valve 12 and enters the rodless chambers of the left cylinder 8 and the right cylinder 9 of the first stack respectively. At the same time, it enters the rodless chambers of the left cylinder 10 and the right cylinder 11 of the second stack. Under the action of the oil pressure, the piston rods of the left cylinder 8 and the right cylinder 9 of the first stack are pushed upward, and the piston rods of the left cylinder 10 and the right cylinder 11 of the second stack are also pushed upward, completing the combined lifting action of the first and second stacks.

[0054] The oil pressure value of the second pressure sensor 5.5 is detected in real time. When the pressure value exceeds the preset pressure value, the speed of the control motor 16 is reduced to the preset speed, the speed of the gear pump 17 is also reduced, and the output flow of the gear pump 17 is reduced to achieve the control of the heavy-load and light-load combined lifting speed of the first and second stacks. At the same time, the displacement height value of the displacement sensor 7 installed on the left oil cylinder 8 of the first stack is detected in real time. When the relative displacement exceeds the preset height value, the speed of the control motor 16 is reduced to the preset speed, and the speed of the gear pump 17 is also reduced accordingly. The output flow of the gear pump 17 is reduced, and the speed of the first stack is reduced. When the lifting height of the first stack exceeds the preset height value, the second solenoid valve 5.6 loses power and switches to the right position, the oil circuit is cut off, and the fourth solenoid valve 5.3 is controlled to be energized and switched to the right position. The oil passes through the right position of the second flow compensation valve 5.2, passes through the return oil port T, flows into the radiator 3 through the third tee 21, flows into the return oil filter 2 through the fourth tee 22, and flows back to the hydraulic oil tank 1, completing the descent of the second stack to the lowest position, ensuring the stability of the entire vehicle when the first stack is lifted. The positions of the first photoelectric switches 23 and 25 are detected in real time. When the first and second stacks are about to be lifted to the top, the speed slope of the control motor 16 is reduced, the output flow slope of the gear pump 17 is reduced, and the lifting speed is gradually reduced, thereby achieving buffer control of the first and second stacks being lifted to the top.

[0055] After the first and second stacks are lifted to the top, the system oil pressure exceeds the pressure of relief valve 5.11. Relief valve 5.11 opens, flows through the return port T of control valve block assembly 5, through the third tee 21, into radiator 3, through the fourth tee 22, into return filter 2, and then back to hydraulic tank 1, completing overload protection. If radiator 3 becomes clogged and the oil pressure exceeds the pressure of bypass check valve 4, bypass check valve 4 opens, and the oil flows through tee 22 and return filter 2 back to hydraulic tank 1. If the oil pressure in the return filter 2 exceeds the pressure of bypass check valve 2.1, bypass check valve 2.1 opens, and the oil flows back to hydraulic tank 1.

[0056] The first stack is raised and the second stack is lowered:

[0057] When both the first solenoid valve 5.7 and the second solenoid valve 5.3 are energized, the first solenoid valve 5.7 is switched to the left position, and the fourth solenoid valve 5.3 is switched to the right position. The motor 16 starts to drive the gear pump 17 to work, and the oil flows from the hydraulic tank 1 through the oil suction filter 18 into the gear pump 17 to the oil inlet P of the control valve block assembly 5, passes through the one-way valve 5.10, enters the first solenoid valve 5.7, passes through the oil port A of the control valve block assembly 5, passes through the first three-way valve 13, enters the explosion-proof valve 12, and enters the rodless chambers of the left oil cylinder 8 of the first stack and the right oil cylinder 9 of the first stack respectively, and pushes the second oil cylinder 8 and the second oil cylinder 9 of the first stack under the action of oil pressure. The piston rods of the left cylinder 8 of the first stack and the right cylinder 9 of the first stack move upward, while the left cylinder 10 of the second stack and the right cylinder 11 of the second stack descend under the action of gravity, pushing the oil in the rodless chamber through the second tee 14 and into the oil port B of the control valve block assembly 5. Then, through the second return oil passage 5.14, it enters the right position of the fourth solenoid valve 5.3, passes through the right position of the second flow compensation valve 5.2, flows through the return oil port T, flows through the third tee 21 into the radiator 3, and flows through the fourth tee 22 into the return oil filter 2, and then returns to the hydraulic oil tank 1, completing the combined operation of raising the first stack and lowering the second stack. If the second stack cannot be lowered due to a malfunction of the fourth solenoid valve 5.3 or an electrical fault, the lowering action can be completed by opening the emergency switch valve 5.1.

[0058] The oil pressure values ​​of the first pressure sensors 5.4 and 5.5 are monitored in real time. When the pressure values ​​exceed a preset value, the speed of the motor 16 is controlled to be reduced to a preset speed, and the speed of the gear pump 17 is also reduced accordingly, reducing the output flow rate of the gear pump 17. At the same time, the current ramp of the fourth solenoid valve 5.3 is controlled to decrease, and the opening of the fourth solenoid valve 5.3 is controlled to gradually decrease to a preset speed, thereby achieving the heavy-load and light-load speed control of the combined operation of raising the first stack and lowering the second stack. At the same time, the displacement height value of the displacement sensor 7 installed in the left oil cylinder 8 of the first stack is monitored in real time. When the relative displacement height exceeds a preset height value, the speed of the motor 16 is controlled to be reduced to a preset speed, and the speed of the gear pump 17 is also reduced accordingly, reducing the output flow rate of the gear pump 17, and adjusting the speed of the first stack raising and the second stack lowering. The positions of the photoelectric switches 23 and 25 are detected in real time. When the first stack is about to be lifted to the top and the second stack is about to be lowered to the bottom, the speed slope of the control motor 16 is reduced, the output flow slope of the gear pump 17 is reduced, and the lifting speed is gradually reduced, thereby achieving buffer control of the first stack being lifted to the top. The current slope of the fourth solenoid valve 5.3 is controlled to be reduced, the opening of the fourth solenoid valve 5.3 is controlled to be gradually reduced, and the descending speed is gradually reduced, thereby achieving buffer control of the descending speed of the second stack.

[0059] After the first lift reaches the top, the system oil pressure exceeds the pressure value of relief valve 5.11, which opens. The oil flows through the return port T of the control valve block assembly 5, through the third tee 21, into the radiator 3, and through the fourth tee 22 into the return oil filter 2, before returning to the hydraulic oil tank 1, completing overload protection. If the radiator 3 becomes clogged and the oil pressure exceeds the pressure value of the bypass check valve 4, the bypass check valve 4 opens, and the oil flows through the fourth tee 22 and return oil filter 2 back to the hydraulic oil tank 1. If the oil pressure in the return oil filter 2 exceeds the pressure value of the bypass check valve 2.1, the bypass check valve 2.1 opens, and the oil flows back to the hydraulic oil tank 1.

[0060] The first stack descends and the second stack rises:

[0061] When the third solenoid valve 5.8 and the second solenoid valve 5.6 are both energized, the fourth solenoid valve 5.3 is switched to the right position, and the second solenoid valve 5.6 is switched to the left position. The motor 16 starts and drives the gear pump 17 to work. The oil flows from the hydraulic tank 1 through the oil suction filter 18 into the gear pump 17 to the oil inlet P of the control valve block assembly 5, passes through the one-way valve 5.10, enters the second solenoid valve 5.6, passes through the oil port B of the control valve block assembly 5, passes through the second three-way valve 14, and enters the rodless cavity of the second stack left cylinder 10 and the second stack right cylinder 11. Under the action of the oil pressure, the left cylinder of the second stack is pushed. The piston rods of the oil cylinder 10 and the second stack right oil cylinder 11 move upward. At the same time, the first stack left oil cylinder 8 and the first stack right oil cylinder 9 descend under the action of gravity, pushing the oil in the rodless chamber through the first tee 13 and into the oil port A of the control valve block assembly 5. Then, through the first return oil channel 5.13, it enters the right position of the third solenoid valve 5.8, passes through the right position of the first flow compensation valve 5.9, passes through the return oil port T, flows into the radiator 3 through the third tee 21, flows into the return oil filter 2 through the fourth tee 22, and flows back to the hydraulic oil tank 1, completing the combined operation of lowering the first stack and lifting the second stack.

[0062] If the first stack cannot be lowered due to a fault in the third solenoid valve 5.8 or an electrical fault, the lowering action can be completed by opening the emergency switch valve 5.12.

[0063] The oil pressure values ​​of the first and second pressure sensors 5.4 and 5.5 are monitored in real time. When the pressure values ​​exceed a preset value, the speed of the motor 16 is controlled to be reduced to a preset speed, and the speed of the gear pump 17 is also reduced accordingly, reducing the output flow of the gear pump 17. The current ramp of the third solenoid valve 5.8 is controlled to decrease, and the opening of the third solenoid valve 5.8 is controlled to gradually decrease to a preset speed, thereby achieving heavy-load and light-load speed control for the combined operation of lowering the first stack and raising the second stack. The displacement height value of the displacement sensor 7 installed on the left cylinder 8 of the first stack is monitored in real time. When the displacement height value exceeds a preset value, the speed of the motor 16 is controlled to be reduced to a preset speed, and the speed of the gear pump 17 is also reduced accordingly, reducing the output flow of the gear pump 17, and controlling the speed of the first stack lowering and the second stack raising. The position of the electric switch is detected in real time. When the first stack is about to descend to the bottom and the second stack is about to rise to the top, the speed slope of the control motor 16 is reduced, the output flow slope of the gear pump 17 is reduced, and the lifting speed is gradually reduced, so as to achieve buffer control of the second stack rising to the top. The current slope of the third solenoid valve 5.8 is controlled to decrease, the solenoid valve opening is controlled to gradually decrease, and the descending speed is gradually reduced, so as to achieve buffer control of the descending speed of the first stack.

[0064] After the second lift reaches the top, the system oil pressure exceeds the pressure of safety relief valve 5.11, which opens. The oil flows through the return port T of the control valve block assembly 5, through tee 21, into radiator 3, and then through tee 22 into return filter 2, returning to the hydraulic oil tank 1, completing overload protection. If radiator 3 becomes clogged and the oil pressure exceeds the pressure of bypass check valve 4, bypass check valve 4 opens, and the oil flows through tee 22 and return filter 2 back to the hydraulic oil tank 1. If the oil pressure in the return filter 2 exceeds the pressure of bypass check valve 2.1, bypass check valve 2.1 opens, and the oil flows back to the hydraulic oil tank 1.

[0065] The first and second stacks descend simultaneously:

[0066] When both the third solenoid valve 5.8 and the fourth solenoid valve 5.3 are energized, they are switched to the right position. At the same time, the left cylinder 8 of the first stack, the right cylinder 9 of the first stack, the left cylinder 10 of the second stack, and the right cylinder 11 of the second stack descend under the action of gravity, pushing the oil in the rodless chamber through the first tee 13 and the second tee 14, flowing into the oil ports A and B of the control valve block assembly 5, passing through the first return oil passage 5.13 and the second return oil passage 5.14, entering the right position of the third solenoid valve 5.8 and the fourth solenoid valve 5.3, passing through the right position of the first flow compensation valve 5.9 and the second flow compensation valve 5.2, through the oil return port T, flowing into the radiator 3 through the third tee 21, flowing into the return oil filter 2 through the fourth tee 22, and flowing back to the hydraulic oil tank 1, completing the combined descending operation of the first and second stacks. If the third solenoid valve 5.8 or the fourth solenoid valve 5.3 fails or an electrical fault causes the stack to be unable to descend, the emergency switch valve can be opened to complete the lowering of the first and second stacks.

[0067] The oil pressure values ​​of the first and second pressure sensors 5.4 and 5.5 are monitored in real time. When the pressure values ​​exceed the preset values, the current ramp of the fourth and third solenoid valves 5.3 and 5.8 is controlled to decrease, and the openings of the fourth and third solenoid valves 5.3 and 5.8 are controlled to gradually decrease, and the descent is reduced to the preset speed, achieving heavy-load and light-load speed control for the combined operation of lowering the first stack and raising the second stack. The position of the photoelectric switch is monitored in real time. When the first and second stacks are about to reach the bottom, the current ramp of the fourth and third solenoid valves 5.3 and 5.8 is controlled to decrease, and the openings of the fourth and third solenoid valves 5.3 and 5.8 are controlled to gradually decrease, gradually reducing the speed of the first and second stacks, achieving buffer control of the descent speed of the first and second stacks.

[0068] When radiator 3 is clogged and the oil pressure exceeds the pressure value of bypass check valve 4, bypass check valve 4 opens and flows back to hydraulic oil tank 1 through tee 22 and return oil filter 2. When the oil pressure exceeds the pressure value of bypass check valve 2.1 in the return oil filter 2, bypass check valve 2.1 opens and flows back to hydraulic oil tank 1.

[0069] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0070] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A double stacker hydraulic system, characterized in that: It comprises a first stacking hydraulic cylinder group and a second stacking hydraulic cylinder group, wherein the first stacking hydraulic cylinder group and the second stacking hydraulic cylinder group are connected to an oil supply pipeline via a control valve block assembly (5); The control valve block assembly (5) includes an oil inlet pipeline and an oil return pipeline. The oil inlet pipeline is connected to the oil supply pipeline. The oil inlet pipeline is connected to the first stacked hydraulic cylinder group and the second stacked hydraulic cylinder group through a first oil inlet branch pipe and a second oil inlet branch pipe respectively. The first oil inlet branch pipe and the second oil inlet branch pipe are both provided with a solenoid valve. The oil return pipeline includes a first oil return oil passage (5.13) and a second oil return oil passage (5.14) connected to the first oil inlet branch pipe and the second oil inlet branch pipe. The first oil return oil passage (5.13) and the second oil return oil passage (5.14) are both provided with a solenoid valve.

2. A double stacker hydraulic system according to claim 1, characterized in that: The oil supply pipeline comprises a hydraulic oil tank (1) and a gear pump (17), and the oil inlet pipeline is connected to the hydraulic oil tank (1) via the gear pump (17).

3. A double stacker hydraulic system according to claim 2, characterized in that: The gear pump (17) is connected to a motor (16) for driving the gear pump (17), and a motor temperature sensor (15) is provided on the motor (16).

4. A double stacker hydraulic system according to claim 2, characterized in that: An oil suction filter (18) is provided at the oil inlet end of the gear pump (17), and a hydraulic oil temperature sensor (19) is provided at the oil outlet end of the gear pump (17).

5. The hydraulic system of a double stacker according to claim 1, characterized in that: A one-way valve (5.10) is provided on the oil inlet pipeline, the oil outlet end of the one-way valve (5.10) is connected to the first oil inlet branch pipe and the second oil inlet branch pipe, and the oil inlet end of the one-way valve (5.10) is connected to the oil return pipeline via a relief valve (5.11).

6. A double stacker hydraulic system according to claim 1, characterized in that: The first oil inlet branch pipe is provided with a first solenoid valve (5.7); the first stack hydraulic cylinder group comprises a first stack left oil cylinder (8) and a first stack right oil cylinder (9); the first stack left oil cylinder (8) and the first stack right oil cylinder (9) are connected to the first oil inlet branch pipe through a first three-way connection (13); the oil outlet end of the first oil inlet branch pipe is provided with a first pressure sensor (5.4) and an explosion-proof valve (12); the first stack left oil cylinder (8) and / or the first stack right oil cylinder (9) are provided with a displacement sensor (7) and a first photoelectric switch (23).

7. The hydraulic system of a double stacker according to claim 1, characterized in that: A second solenoid valve (5.6) is provided on the second oil inlet branch pipe. The second stack hydraulic cylinder group comprises a second stack left oil cylinder (10) and a second stack right oil cylinder (11). The second stack left oil cylinder (10) and the second stack right oil cylinder (11) are connected to the second oil inlet branch pipe via a second three-way connection (14). A second pressure sensor (5.5) is provided on the second oil inlet branch pipe. A second photoelectric switch is provided on the second stack left oil cylinder (10) and / or the second stack right oil cylinder (11).

8. The hydraulic system of a double stacker according to claim 1, characterized in that: The first oil return passage (5.13) is provided with a third solenoid valve (5.8) and a first flow compensation valve (5.9); a first emergency switch valve (5.12) is connected in parallel to a bypass of the third solenoid valve (5.8) and the first flow compensation valve (5.9); the second oil return passage (5.14) is provided with a fourth solenoid valve (5.3) and a second flow compensation valve (5.9); a second emergency switch valve (5.1) is connected in parallel to a bypass of the fourth solenoid valve (5.3) and the second flow compensation valve (5.9).

9. The hydraulic system of a double stacker according to claim 2, characterized in that: The first oil return passage (5.13) and the second oil return passage (5.14) are connected to the hydraulic oil tank (1) through an oil return main pipe. A radiator (3) is provided on the oil return main pipe. A fan (20) is provided on one side of the radiator (3). A bypass valve (4) is connected in parallel to the radiator (3). The bypass valve (4) is connected to the oil inlet and oil outlet of the radiator (3) through a third three-way valve (21) and a fourth three-way valve (22). A return oil filter (2) is provided at the oil outlet of the oil return main pipe. A bypass check valve (2.1) is provided on the return oil filter (2).

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