阅读说明：本技术 用于升降装置的液压控制系统 (Hydraulic control system for lifting device ) 是由 张三喜 方敏 鄢勇 周虎 于 2021-07-09 设计创作，主要内容包括：本公开提供了一种用于升降装置的液压控制系统,属于液压驱动控制领域。液压控制系统包括动力输出单元、升降单元和执行油缸；升降单元包括调速阀、第一电磁换向阀、第一溢流阀和第二溢流阀；调速阀的第一油口与所述动力输出单元的出油口连通,调速阀的第二油口与所述执行油缸的无杆腔连通；所述第一溢流阀的进油口与所述动力输出单元的出油口连通,所述第一溢流阀的回油口与所述动力输出单元的回油口连通,所述第一溢流阀的控制油口与所述第一溢流阀的进油口连通；第一电磁换向阀的进油口与所述第一溢流阀的弹簧信号口连通,第一电磁换向阀的工作油口与所述执行油缸的无杆腔连通。本公开通过液压控制系统,可以简化液压控制系统的油路。(The disclosure provides a hydraulic control system for a lifting device, and belongs to the field of hydraulic drive control. The hydraulic control system comprises a power output unit, a lifting unit and an execution oil cylinder; the lifting unit comprises a speed regulating valve, a first electromagnetic directional valve, a first overflow valve and a second overflow valve; a first oil port of the speed regulating valve is communicated with an oil outlet of the power output unit, and a second oil port of the speed regulating valve is communicated with a rodless cavity of the execution oil cylinder; an oil inlet of the first overflow valve is communicated with an oil outlet of the power output unit, an oil return port of the first overflow valve is communicated with an oil return port of the power output unit, and a control oil port of the first overflow valve is communicated with an oil inlet of the first overflow valve; an oil inlet of the first electromagnetic directional valve is communicated with a spring signal port of the first overflow valve, and a working oil port of the first electromagnetic directional valve is communicated with a rodless cavity of the execution oil cylinder. This disclosure can simplify the oil circuit of hydraulic control system through hydraulic control system.)

1. A hydraulic control system for a lifting device, characterized in that the hydraulic control system comprises a power take-off unit (1), a lifting unit (2) and an actuating cylinder (3);

the lifting unit (2) comprises a speed regulating valve (21), a first electromagnetic directional valve (22), a first overflow valve (23) and a second overflow valve (24);

a first oil port (a) of the speed regulating valve (21) is communicated with an oil outlet of the power output unit (1), and a second oil port (b) of the speed regulating valve (21) is communicated with a rodless cavity of the execution oil cylinder (3);

an oil inlet (P) of the first overflow valve (23) is communicated with an oil outlet of the power output unit (1), an oil return port (T) of the first overflow valve (23) is communicated with an oil return port of the power output unit (1), and a control oil port (X) of the first overflow valve (23) is communicated with the oil inlet (P) of the first overflow valve (23);

an oil inlet (P) of the first electromagnetic directional valve (22) is communicated with a spring signal port (LS) of the first overflow valve (23), and a working oil port (A) of the first electromagnetic directional valve (22) is communicated with a rodless cavity of the execution oil cylinder (3);

an oil inlet (P) of the second overflow valve (24) is communicated with an oil return port (T) of the first electromagnetic directional valve (22), the oil return port (T) of the second overflow valve (24) is communicated with an oil return port of the power output unit (1), and a control oil port (X) of the second overflow valve (24) is communicated with the oil inlet (P) of the second overflow valve (24).

2. The hydraulic control system according to claim 1, characterized in that the lifting unit (2) further comprises a pilot operated check valve (25) and a second solenoid directional valve (26);

a first oil port (a) of the hydraulic control one-way valve (25) is respectively communicated with a second oil port (b) of the speed regulating valve (21) and a working oil port (A) of the first electromagnetic directional valve (22), and the second oil port (b) of the hydraulic control one-way valve (25) is communicated with a rodless cavity of the execution oil cylinder (3);

an oil inlet (P) of the second electromagnetic directional valve (26) is communicated with a control port (X) of the hydraulic control one-way valve (25), and a working oil port (A) of the second electromagnetic directional valve (26) is communicated with a rodless cavity of the execution oil cylinder (3).

3. The hydraulic control system according to claim 2, wherein the lifting unit (2) further comprises a manual directional control valve (27), a first oil port (a) of the manual directional control valve (27) is communicated with the rodless cavity of the execution cylinder (3), and a second oil port (b) of the manual directional control valve (27) is communicated with an oil return port of the power take-off unit (1).

4. The hydraulic control system of claim 3, wherein the lifting unit (2) further comprises a sequence valve (28);

an oil inlet (P) of the sequence valve (28) is communicated with a second oil port (b) of the manual reversing valve (27), an oil return port (T) of the sequence valve (28) is communicated with an oil return port of the power output unit (1), and a control oil port (X) of the sequence valve (28) is communicated with the oil inlet (P) of the sequence valve (28).

5. The hydraulic control system according to claim 4, characterized in that it further comprises an explosion-proof valve (4);

the hydraulic control explosion-proof valve is characterized in that a first oil port (a) of the explosion-proof valve (4) is communicated with a second oil port (b) of the hydraulic control one-way valve (25), a first oil port (a) of the manual reversing valve (27) and a working oil port (a) of the second electromagnetic reversing valve (26), a second oil port (b) of the explosion-proof valve (4) is communicated with a rodless cavity of the execution oil cylinder (3), a third oil port (c) of the explosion-proof valve (4) is communicated with the first oil port (a), and a fourth oil port (d) of the explosion-proof valve (4) is communicated with the second oil port (b).

6. The hydraulic control system according to any one of claims 1-5, characterized in that the lifting unit (2) further comprises a first non-return valve (29);

and a first oil port (a) of the first check valve (29) is communicated with an oil outlet of the power output unit (1), and a second oil port (b) of the first check valve (29) is communicated with an oil inlet (P) of the first overflow valve (23) and a first oil port (a) of the speed regulating valve (21).

7. A hydraulic control system according to any one of claims 1-5, characterised in that the governor valve (21) is an electric proportional governor valve.

8. A hydraulic control system according to any one of claims 1-5, characterized in that the hydraulic control system further comprises a controller, which is electrically connected to the governor valve (21) and to a displacement sensor in the actuator cylinder (3).

9. The hydraulic control system according to any one of claims 1-5, characterized in that the power take-off unit (1) comprises an electric motor (11) and a main pump (12), a tank (13);

the motor (11) is used for driving the main pump (12), and an oil inlet of the main pump (12) is communicated with the oil tank (13).

10. The hydraulic control system of claim 9, wherein the power take-off unit further includes a filter (14);

an oil inlet of the filter (14) is communicated with the oil tank (13), and an oil outlet of the filter (14) is communicated with an oil inlet of the main pump (12).

Technical Field

The disclosure belongs to the field of hydraulic drive control, and particularly relates to a hydraulic control system for a lifting device.

Background

A lifting device (e.g., a crane) is a common hoisting machine, which is used for lifting and lowering heavy objects and is widely used in the field of machinery.

In the related art, the lifting device is controlled by a hydraulic control system, and the hydraulic control system mainly comprises a power output unit, a reversing valve and an execution oil cylinder. The power output unit is communicated with the execution oil cylinder through the reversing valve, so that the power output unit can be controlled to input hydraulic energy to a rod cavity and a rodless cavity of the execution oil cylinder through the reversing valve, the execution oil cylinder is driven to shorten or extend, and the lifting function of the lifting device is further realized.

However, when the power output unit is communicated with the execution cylinder through the reversing valve, an oil inlet path and an oil return path are often required to be respectively arranged, so that the oil path arrangement is complex and the cost is high.

Disclosure of Invention

The embodiment of the disclosure provides a hydraulic control system for a lifting device, which can simplify an oil circuit of the hydraulic control system and further reduce cost. The technical scheme is as follows:

the embodiment of the disclosure provides a hydraulic control system, which comprises a power output unit, a lifting unit and an execution oil cylinder;

the lifting unit comprises a speed regulating valve, a first electromagnetic directional valve, a first overflow valve and a second overflow valve;

a first oil port of the speed regulating valve is communicated with an oil outlet of the power output unit, and a second oil port of the speed regulating valve is communicated with a rodless cavity of the execution oil cylinder;

an oil inlet of the first overflow valve is communicated with an oil outlet of the power output unit, an oil return port of the first overflow valve is communicated with an oil return port of the power output unit, and a control oil port of the first overflow valve is communicated with an oil inlet of the first overflow valve;

an oil inlet of the first electromagnetic directional valve is communicated with a spring signal port of the first overflow valve, and a working oil port of the first electromagnetic directional valve is communicated with a rodless cavity of the execution oil cylinder;

an oil inlet of the second overflow valve is communicated with an oil return port of the first electromagnetic directional valve, an oil return port of the second overflow valve is communicated with an oil return port of the power output unit, and a control oil port of the second overflow valve is communicated with an oil inlet of the second overflow valve.

In yet another implementation of the present disclosure, the lifting unit further includes a pilot operated check valve and a second solenoid directional valve;

a first oil port of the hydraulic control one-way valve is respectively communicated with a second oil port of the speed regulating valve and a working oil port of the first electromagnetic directional valve, and a second oil port of the hydraulic control one-way valve is communicated with a rodless cavity of the execution oil cylinder;

an oil inlet of the second electromagnetic directional valve is communicated with a control port of the hydraulic control one-way valve, and a working oil port of the second electromagnetic directional valve is communicated with a rodless cavity of the execution oil cylinder.

In another implementation manner of the present disclosure, the lifting unit further includes a manual directional valve, a first oil port of the manual directional valve is communicated with the rodless cavity of the actuating cylinder, and a second oil port of the manual directional valve is communicated with an oil return port of the power output unit.

In yet another implementation of the present disclosure, the lift unit further comprises a sequence valve;

an oil inlet of the sequence valve is communicated with a second oil port of the manual reversing valve, an oil return port of the sequence valve is communicated with an oil return port of the power output unit, and a control oil port of the sequence valve is communicated with an oil inlet of the sequence valve.

In yet another implementation of the present disclosure, the hydraulic control system further comprises an explosion-proof valve;

the first oil port of the explosion-proof valve is communicated with the second oil port of the hydraulic control one-way valve, the first oil port of the manual reversing valve and the working oil port of the second electromagnetic reversing valve, the second oil port of the explosion-proof valve is communicated with the rodless cavity of the execution oil cylinder, the third oil port of the explosion-proof valve is communicated with the first oil port of the explosion-proof valve, and the fourth oil port of the explosion-proof valve is communicated with the second oil port of the explosion-proof valve.

In yet another implementation of the present disclosure, the lifting unit further comprises a first one-way valve;

and a first oil port of the first check valve is communicated with an oil outlet of the power output unit, and a second oil port of the first check valve is communicated with an oil inlet of the first overflow valve and a first oil port of the speed regulating valve.

In yet another implementation of the present disclosure, the speed valve is an electrically proportional speed valve.

In yet another implementation of the present disclosure, the hydraulic control system further includes a controller electrically connected to the speed valve and the displacement sensor in the actuation cylinder.

In yet another implementation of the present disclosure, the power take-off unit includes an electric motor and a main pump, an oil tank;

the motor is used for driving the main pump, and an oil inlet of the main pump is communicated with the oil tank.

In yet another implementation of the present disclosure, the power take-off unit further includes a filter;

the oil inlet of the filter is communicated with the oil tank, and the oil outlet of the filter is communicated with the oil inlet of the main pump.

The technical scheme provided by the embodiment of the disclosure has the following beneficial effects:

when the hydraulic control system provided by the embodiment of the disclosure is used for driving the lifting device, the power output unit is started firstly, so that hydraulic oil output by the power output unit enters the rodless cavity of the execution oil cylinder through the speed regulating valve, and meanwhile, the hydraulic oil output by the power output unit enters the oil inlet P of the first overflow valve. Then the first electromagnetic directional valve in the lifting unit is controlled to be electrified, the first electromagnetic directional valve is located on the right side, hydraulic oil output by the power output unit enters the first electromagnetic directional valve through the speed regulating valve, and then enters a pilot spring cavity of the first overflow valve through the first electromagnetic directional valve, when the pressure difference at the two ends of the speed regulating valve is not smaller than the pressure value of the pilot spring cavity in the first overflow valve, namely when the first electromagnetic directional valve is located at a small opening position, the execution oil cylinder moves at a lower speed, at the moment, the first overflow valve is opened, the first overflow valve releases redundant hydraulic oil, and the stable rising of a heavy object is ensured. When the pressure difference between the two ends of the speed regulating valve is smaller than the pressure value of a pilot spring cavity in the first overflow valve, the first electromagnetic directional valve is in a large opening position, the execution oil cylinder moves at a high speed, the first overflow valve is closed at the moment, hydraulic oil directly enters the execution oil cylinder after passing through the speed regulating valve, and the heavy object is guaranteed to rise quickly.

When the heavy object needs to be lowered, the power output unit stops working, at the moment, the hydraulic oil in the rodless cavity in the execution oil cylinder automatically flows to the speed regulating valve under the action of the gravity of the heavy object, then enters the oil inlet P of the first overflow valve through the speed regulating valve and enters the pilot spring cavity of the first overflow valve. At the moment, the first electromagnetic directional valve is controlled to lose power, the first electromagnetic directional valve is located at the left position, and hydraulic oil in a pilot spring cavity of the first overflow valve enters the second overflow valve. When the pressure in the pilot spring cavity of the first overflow valve is larger than the back pressure of the second overflow valve, the second overflow valve is opened to release the pressure in the pilot spring cavity of the first overflow valve, then the first overflow valve is opened under the action of the pressure difference of the pilot spring cavity, and the hydraulic oil flows to the power output unit, so that the stability of the descending action is ensured.

The hydraulic control system provided by the embodiment of the disclosure uses the same oil path as the oil inlet path and the oil return path respectively when the heavy object is lifted, and does not need to design the separate oil inlet path and the separate oil return path respectively, so that the layout of the oil path is greatly reduced, the oil path arrangement of the hydraulic control system is simplified, the applicability of the hydraulic control system is improved, and the cost is reduced.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic diagram of a hydraulic control system provided by an embodiment of the present disclosure.

The symbols in the drawings represent the following meanings:

1. a power output unit; 11. an electric motor; 12. a main pump; 13. an oil tank; 14. a filter;

2. a lifting unit; 21. a speed regulating valve; 22. a first electromagnetic directional valve; 23. a first overflow valve; 24. a second overflow valve; 25. a hydraulic control check valve; 26. a second electromagnetic directional valve; 27. a manual directional control valve; 28. a sequence valve; 29. a first check valve;

3. an execution oil cylinder;

4. an explosion-proof valve.

Detailed Description

To make the objects, technical solutions and advantages of the present disclosure more apparent, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

The disclosed embodiment provides a hydraulic control system for a lifting device, and as shown in fig. 1, the hydraulic control system includes a power output unit 1, a lifting unit 2, and an execution cylinder 3. The lifting unit 2 includes a speed regulating valve 21, a first electromagnetic directional valve 22, a first overflow valve 23, and a second overflow valve 24. The first oil port a of the speed regulating valve 21 is communicated with the oil outlet of the power output unit 1, and the second oil port b of the speed regulating valve 21 is communicated with the rodless cavity of the actuating cylinder 3.

An oil inlet P of the first overflow valve 23 is communicated with an oil outlet of the power output unit 1, an oil return port T of the first overflow valve 23 is communicated with an oil return port of the power output unit 1, and a control oil port X of the first overflow valve 23 is communicated with the oil inlet P of the first overflow valve 23.

An oil inlet P of the first electromagnetic directional valve 22 is communicated with a spring signal port LS of the first overflow valve 23, and a working oil port A of the first electromagnetic directional valve 22 is communicated with a rodless cavity of the execution oil cylinder 3.

An oil inlet P of the second overflow valve 24 is communicated with an oil return port T of the first electromagnetic directional valve 22, the oil return port T of the second overflow valve 24 is communicated with an oil return port of the power output unit 1, and a control oil port X of the second overflow valve 24 is communicated with the oil inlet P of the second overflow valve 24.

When the hydraulic control system provided by the embodiment of the disclosure is used for driving the lifting device, the power output unit 1 is started first, so that the hydraulic oil output by the power output unit 1 enters the rodless cavity of the actuating cylinder 3 through the speed regulating valve 21, and meanwhile, the hydraulic oil output by the power output unit 1 enters the oil inlet P of the first overflow valve 23. Then the first electromagnetic directional valve 22 in the lifting unit 2 is controlled to be powered on, the first electromagnetic directional valve 22 is located on the right side, the hydraulic oil output by the power output unit 1 enters the first electromagnetic directional valve 22 through the speed regulating valve 21, and then enters the pilot spring cavity of the first overflow valve 23 through the first electromagnetic directional valve 22, when the pressure difference between the two ends of the speed regulating valve 21 is not less than the pressure value of the pilot spring cavity in the first overflow valve 23, that is, when the first electromagnetic directional valve 22 is located at the small opening position, the execution oil cylinder 3 moves at a lower speed, at this time, the first overflow valve 23 is opened, the first overflow valve 23 releases redundant hydraulic oil, and the stable lifting of the heavy object is ensured. When the pressure difference between the two ends of the speed regulating valve 21 is smaller than the pressure value of a pilot spring cavity in the first overflow valve 23, the first electromagnetic directional valve 22 is in a large opening position, the execution oil cylinder 3 moves at a high speed, at the moment, the first overflow valve 23 is closed, hydraulic oil directly enters the execution oil cylinder 3 after passing through the speed regulating valve 21, and the heavy object is ensured to rise quickly.

When a heavy object needs to be lowered, the power output unit 1 stops working, at this time, the hydraulic oil in the rodless cavity in the execution oil cylinder 3 automatically flows to the speed regulating valve 21 under the action of the gravity of the heavy object, then enters the oil inlet P of the first overflow valve 23 through the speed regulating valve 21, and enters the pilot spring cavity of the first overflow valve 23. At this time, the first electromagnetic directional valve 22 is controlled to be de-energized, the first electromagnetic directional valve 22 is positioned at the left position, and the hydraulic oil in the pilot spring chamber of the first relief valve 23 enters the second relief valve 24. When the pressure in the pilot spring cavity of the first overflow valve 23 is greater than the back pressure of the second overflow valve 24, the second overflow valve 24 is opened to release the pressure in the pilot spring cavity of the first overflow valve 23, then the first overflow valve 23 is opened under the action of the differential pressure of the pilot spring cavity, and the hydraulic oil flows into the power output unit 1 to ensure the stability of the descending action.

The hydraulic control system provided by the embodiment of the disclosure uses the same oil path as the oil inlet path and the oil return path respectively when the heavy object is lifted, and does not need to design the separate oil inlet path and the separate oil return path respectively, so that the layout of the oil path is greatly reduced, the oil path arrangement of the hydraulic control system is simplified, the applicability of the hydraulic control system is improved, and the cost is reduced.

In this embodiment, the first relief valve 23 is a pressure-loss relief valve.

The first overflow valve 23 is a pressure-loss overflow valve, and 2 springs are arranged in the first overflow valve 23, wherein one spring is a pilot spring, and the other spring is a main spring. Thus, the device can play the roles of constant pressure overflow, pressure stabilization, system unloading and safety protection.

Illustratively, the speed valve 21 is an electrically proportional speed valve.

The speed regulating valve 21 is an electric proportional speed regulating valve, a proportional electromagnet can be used for replacing a throttle valve or a manual regulating device of the speed regulating valve, the flow of the speed regulating valve can be continuously or proportionally and remotely controlled by controlling the opening of a throttle orifice by using an input electric signal, further the speed regulation of the execution oil cylinder 3 is realized, the regulation precision of the execution oil cylinder 3 is improved, and the speed of the execution oil cylinder 3 is conveniently controlled.

That is, when different electric signals are input, the electromagnet of the speed control valve 21 receives different electromagnetic forces, and accordingly, different throttle opening degrees are provided.

In this embodiment, the spool of the speed valve 21 can be continuously moved from the left position to the right position or continuously moved from the right position to the left position by inputting different electrical signals.

Alternatively, the power output unit 1 includes an electric motor 11, a main pump 12 and an oil tank 13, the electric motor 11 is used for driving the main pump 12, and an oil inlet of the main pump 12 is communicated with the oil tank 13.

The electric motor 11 is used for driving the main pump 12 to rotate. The oil tank 13 is used for supplying power hydraulic oil for the whole hydraulic control system. The main pump 12 is used for pumping power hydraulic oil for the hydraulic control system, so that the rodless cavity in the execution cylinder 3 can be filled with hydraulic oil, and finally the lifting device can be driven by the hydraulic control system to lift.

Illustratively, the main pump 12 is a fixed displacement pump.

Set up main pump 12 into the constant delivery pump, can make main pump 12 under the invariable condition of rotational speed, the flow of output be the fixed value, and the rotational speed of main pump 12 selects the back promptly, and the output flow that corresponds just can not change for the output flow of main pump 12 can only rely on the rotational speed of adjustment self to change, and then ensures that elevating gear when going up and down, can not influence its lifting speed because of the output flow of main pump 12, finally improves this elevating gear's lift security performance.

Optionally, the power output unit further includes a filter 14, the filter 14 is disposed between the oil tank 13 and the main pump 12, an oil inlet of the filter 14 is communicated with the oil tank 13, and an oil outlet of the filter 14 is communicated with an oil inlet of the main pump 12.

In the above implementation manner, the addition of the filter 14 can improve the use safety of the hydraulic control system, and prevent impurities from entering the main pump 12, and then enter the whole oil path under the driving of the main pump 12, thereby affecting the use of each valve member, and simultaneously avoiding affecting the normal use of the actuating cylinder 3.

In this embodiment, in order to enable the hydraulic oil in the oil tank 13 to meet the temperature requirement of actual use, a thermometer is usually disposed on the sidewall of the oil tank 13, so that whether the temperature in the oil tank 13 meets the actual requirement can be observed in real time through the thermometer.

For the same reason, in order to ensure that the oil in the oil tank 13 can meet the actual use requirement, a liquid level meter is usually arranged on the side wall of the oil tank 13, so that the depth of the hydraulic oil in the oil tank 13 can be observed in real time through the liquid level meter, and the volume of the hydraulic oil in the oil tank 13 is determined.

Optionally, the lifting unit 2 further comprises a pilot operated check valve 25 and a second solenoid directional valve 26. The first oil port a of the hydraulic control check valve 25 is respectively communicated with the second oil port b of the speed regulating valve 21 and the working oil port a of the first electromagnetic directional valve 22, and the second oil port b of the hydraulic control check valve 25 is communicated with the rodless cavity of the actuating cylinder 3.

An oil inlet P of the second electromagnetic directional valve 26 is communicated with a control port X of the hydraulic control one-way valve 25, and a working oil port A of the second electromagnetic directional valve 26 is communicated with a rodless cavity of the execution oil cylinder 3.

In the implementation manner, the hydraulic control one-way valve 25 and the second electromagnetic directional valve 26 together can control the flow direction of the hydraulic oil in the oil path between the speed regulating valve 21 and the execution oil cylinder 3, so that the oil path between the speed regulating valve 21 and the execution oil cylinder 3 can only flow in one direction according to different working conditions, and the overall safety of the hydraulic control system is further improved.

When the heavy object needs to rise, the hydraulic oil output by the main pump 12 enters the rodless cavity of the execution cylinder 3 through the speed regulating valve 21 and the hydraulic control one-way valve 25, and at this time, the electromagnet of the second electromagnetic directional valve 26 is in a power-off state, that is, the hydraulic control one-way valve 25 can only allow the hydraulic oil to flow from the speed regulating valve 21 to the rodless cavity of the execution cylinder 3.

When the heavy object needs to descend, the motor 11 is stopped at the moment, the electromagnet of the second electromagnetic directional valve 26 is controlled to be powered on, the valve core is located at the right position, the working oil port a of the second electromagnetic directional valve 26 is communicated with the oil outlet T of the second electromagnetic directional valve 26 at the moment, the hydraulic control one-way valve 25 is opened through the second electromagnetic directional valve 26 under the pressure of hydraulic oil caused by gravity, and the hydraulic control one-way valve 25 only can allow the hydraulic oil to flow to the second oil port of the speed regulating valve 21 from the rodless cavity of the execution oil cylinder 3.

Optionally, the lifting unit 2 further comprises a manual directional valve 27, a first oil port a of the manual directional valve 27 is communicated with the rodless cavity of the actuating cylinder 3, and a second oil port b of the manual directional valve 27 is communicated with an oil return port of the oil tank 13.

The manual directional valve 27 can be operated in the emergency situation of the hydraulic control system.

In practical use, when the hydraulic control system needs emergency release, the manual reversing valve 27 can be manually opened, and when a heavy object descends, the gravity enables the hydraulic oil in the rodless cavity of the execution oil cylinder 3 to pass through the manual reversing valve 27, so that the hydraulic oil in the rodless cavity of the execution oil cylinder 3 can directly flow back to the oil tank 13, and the heavy object can be quickly lowered to a required position.

Optionally, the lifting unit 2 further comprises a sequence valve 28, the sequence valve 28 being connected on an oil path between the power take-off unit 1 and the manual directional valve 27.

Wherein, an oil inlet P of the sequence valve 28 is communicated with the second oil port b of the manual reversing valve 27, an oil outlet of the sequence valve 28 is communicated with an oil return port of the power output unit 1, and a control oil port X of the sequence valve 28 is communicated with the oil inlet P of the sequence valve 28.

In the above implementation, the sequence valve 28 is intended to cooperate with the manual directional valve 27 for manipulation in the event of an emergency of the hydraulic control system.

For example, the manual directional valve 27 can be manually opened when the hydraulic control system requires emergency release.

When the heavy object descends, the manual reversing valve 27 is manually opened, and the gravity enables the hydraulic oil in the rodless cavity of the execution oil cylinder 3 to firstly flow to the manual reversing valve 27, and then the sequence valve 28 is controlled to be opened through the manual reversing valve 27, so that the hydraulic oil flows to the oil tank 13 after passing through the sequence valve 28.

Because the control oil port X of the sequence valve 28 is communicated with the oil inlet P of the sequence valve 28, the hydraulic oil entering the sequence valve 28 can be ensured to be in a stable range, and further, the heavy object can be ensured to be stable when descending.

Optionally, the lifting unit 2 further includes a first check valve 29, a first oil port a of the first check valve 29 is communicated with the oil outlet of the power output unit 1, and a second oil port b of the first check valve 29 is communicated with the oil inlet P of the first overflow valve 23 and the first oil port a of the speed regulating valve 21.

In the implementation manner, the first check valve 29 is used to limit the flow direction of the oil paths between the oil inlet P of the first overflow valve 23 and the oil outlet of the main pump 12, and between the oil inlet of the speed regulation valve 21 and the oil outlet of the main pump 12, that is, through setting of the first check valve 29, the hydraulic oil flowing out of the oil outlet of the main pump 12 can only be input to the oil inlet P of the speed regulation valve 21 or the oil inlet P of the first overflow valve 23 in a single direction, but cannot flow in the reverse direction, so that the safety of the hydraulic control system is improved.

Optionally, the hydraulic control system further includes an explosion-proof valve 4, a first oil port a of the explosion-proof valve 4 is communicated with a second oil port b of the hydraulic control check valve 25, a first oil port a of the manual directional valve 27 and a working oil port a of the second electromagnetic directional valve 26, a second oil port b of the explosion-proof valve 4 is communicated with the rodless cavity of the actuating cylinder 3, a third oil port c of the explosion-proof valve 4 is communicated with the first oil port a of the explosion-proof valve 4, and a fourth oil port d of the explosion-proof valve 4 is communicated with the second oil port b of the explosion-proof valve 4.

In the above implementation, the explosion-proof valve 4 locks the actuating cylinder 3 in case of emergency.

When the anti-explosion valve is used, when a hose and the like in a rodless cavity in the execution oil cylinder 3 are broken, the anti-explosion valve 4 can be closed in an emergency manner, so that the execution oil cylinder 3 is locked and prevented from being accidentally injured due to the broken pipeline.

In this embodiment, the diameter of the actuating cylinder 3 is generally large, so that a large load can be supported for lifting movement.

Illustratively, the number of the execution cylinders 3 is more than two, and the rodless cavity of each execution cylinder 3 is communicated with the second oil port b of the explosion-proof valve 4.

By providing more than two actuating cylinders 3, the supporting force of the actuating cylinders 3 can be increased, so that a larger load can be lifted.

Optionally, the hydraulic control system further comprises a controller electrically connected to the speed valve 21 and to position sensors in the actuator cylinder 3.

The displacement sensor in the actuating cylinder 3 is used for detecting the lifting position and the lifting speed of the piston rod in the actuating cylinder 3. The speed regulating valve is electrically connected with the position sensor in the execution oil cylinder 3 through the controller, so that the speed regulating valve 21 can automatically regulate the opening size of the speed regulating valve according to the moving speed of the execution oil cylinder 3, and further the ascending speed of the heavy object is regulated.

The following briefly introduces the working mode of the hydraulic control system provided by the embodiment of the disclosure:

first, the electric motor 11 is started, and hydraulic oil output from the main pump 12 enters the oil inlet P of the first relief valve 23.

When the electromagnet DT1 of the first electromagnetic directional valve 22 is powered on, the first electromagnetic directional valve 22 is located on the right side, the hydraulic oil enters the first electromagnetic directional valve 22 through the speed regulating valve 21, and then enters the pilot spring cavity of the first overflow valve 23 through the first electromagnetic directional valve 22, and at this time, the pressure difference between the two ends of the speed regulating valve 21 is the pressure value of the pilot spring cavity of the first overflow valve 23.

When the electro-proportional magnet DT2 of the speed valve 21 receives a small signal, the speed valve 21 is in the small opening position and the hydraulic system moves at a low speed. When the electric proportional magnet DT2 of the speed valve 21 receives a large signal, the speed valve 21 is in the large opening position and the hydraulic system moves at a high speed. When the differential pressure at the two ends of the speed regulating valve 21 is not less than the pressure value of the pilot spring cavity of the first overflow valve 23, the first overflow valve 23 is opened to discharge the redundant flow.

When the main pump 12 is started, hydraulic oil output from the oil tank 13 enters the rodless chamber of the actuator cylinder 3 through the first check valve 29, and lifts the heavy object.

When the weight needs to be lowered, the motor 11 is stopped. At this time, the electromagnet DT3 of the second electromagnetic directional valve 26 is powered on, the hydraulic oil pressure caused by gravity opens the pilot-operated check valve 25 through the second electromagnetic directional valve 26, and at the same time, the electromagnet DT1 of the first electromagnetic directional valve 22 is powered off, the first electromagnetic directional valve 22 is located at the left position, and the hydraulic oil in the pilot spring cavity of the first overflow valve 23 enters the second overflow valve 24. When the pressure in the pilot spring cavity of the first overflow valve 23 is greater than the back pressure of the second overflow valve 24, the second overflow valve 24 is opened to release the pressure in the pilot spring cavity of the first overflow valve 23, then the first overflow valve 23 is opened under the action of the differential pressure of the pilot spring cavity, and the hydraulic oil flows into the power output unit 1 to ensure the stability of the descending action. The hydraulic oil of the rodless chamber in the actuator cylinder 3 enters the first relief valve 23 through the speed control valve 21, and is thus returned to the oil tank 13.

When the system needs emergency release, the manual reversing valve 27 is manually opened, and hydraulic oil pressure caused by gravity opens the sequence valve 28 through the manual reversing valve 27 so as to return to the oil tank 13, so that heavy objects are stably placed, and safety is guaranteed.

When the hose without the rod cavity of the execution oil cylinder 3 is broken, the explosion-proof valve 4 is closed in an emergency, the execution oil cylinder 3 is locked, and accidental injury caused by the broken hose is prevented.

That is to say, when the heavy object is lifted, the hydraulic control system provided by the embodiment of the disclosure uses the same oil path as the oil inlet path and the oil return path, and does not need to design separate oil inlet path and oil return path, so that the layout of the oil path is greatly reduced, the oil path arrangement of the hydraulic control system is simplified, the applicability of the hydraulic control system is improved, and the cost is reduced.

The above description is meant to be illustrative of the principles of the present disclosure and not to be taken in a limiting sense, and any modifications, equivalents, improvements and the like that are within the spirit and scope of the present disclosure are intended to be included therein.