Energy-saving hydraulic control system and control method for overhead working truck

Abstract

The invention relates to an energy-saving hydraulic control system and method for an overhead working truck, and belongs to the field of overhead working trucks. The two ends of a first oil inlet pipe are connected with a first electromagnetic valve and an oil tank respectively, the two ends of a first oil outlet pipe are connected with a one-way valve and the oil tank respectively, the two ends of a second oil outlet pipe are connected with the one-way valve and a high-precision proportional valve respectively, and the two ends of a second oil inlet pipe are connected with the high-precision proportional valve and the first electromagnetic valve respectively. The two ends of the third oil inlet pipe are connected with the first electromagnetic valve and the lower vehicle proportional valve respectively, the main pump is connected with the engine, the main pump and the overflow valve are arranged on the first oil inlet pipe, the first electromagnetic valve is provided with a first electromagnet and a second electromagnet, the low-precision proportional three-way flow valve is arranged on the second oil inlet pipe, and the lower vehicle proportional valve is arranged on the lower vehicle proportional valve. The second electromagnetic valve and the third electromagnetic valve are both connected with the high-precision proportional valve, the flow distribution valve is connected with the spring, and the flow distribution valve is connected with the first channel and the second channel.

Description

Technical Field

[0001] The invention relates to an energy-saving hydraulic control system and a control method for an aerial work vehicle, belonging to the field of aerial vehicles. Background Art

[0002] In order to make the valve group close to the main pump and oil tank and achieve the purpose of returning the excess hydraulic oil to the oil tank over a shorter distance, some aerial vehicles will place the proportional valve group before the center rotary body. In this way, two oil pipes will pass through the center rotary body for each action, resulting in too many channels in the center rotary body that are difficult to process, and it is difficult to lay the oil pipes passing through the center rotary body. The proportional valve group is placed as a whole behind the center rotary body, so that there will be fewer channels and connecting pipes in the center rotary body, but the valve group is far away from the main pump and oil tank, which will increase the return distance of the hydraulic oil and thus increase energy loss.

[0003] Some actions of aerial vehicles require high-precision control while some actions do not require too high precision. If all high-precision proportional valves are used, the cost will be high; some aerial work vehicles have large chassis engine displacement and surplus output power, which will cause a certain amount of energy waste; after conventional models are left for a period of time after the action, the hydraulic oil will flow back to the tank. At this time, some pipelines will have no hydraulic oil. When the actuator is far away from the control valve group, there will be energy loss caused by action delay and re-filling of the hydraulic oil. Summary of the invention

[0004] The purpose of the present invention is to overcome the above-mentioned deficiencies in the prior art and to provide an energy-saving hydraulic control system and control method for an aerial work vehicle with a reasonable structural design.

[0005] The technical solution adopted by the present invention to solve the above-mentioned problem is: the energy-saving aerial work vehicle hydraulic control system includes a main pump, an engine, a relief valve, a No. 1 solenoid valve, a disembarkation proportional valve, a low-precision proportional three-way flow valve, a one-way valve, a high-precision proportional valve, a No. 2 solenoid valve, a No. 3 solenoid valve, a fuel tank, a No. 1 oil inlet pipe, a No. 1 oil outlet pipe, a No. 2 oil outlet pipe, a No. 2 oil inlet pipe and a No. 3 oil inlet pipe, and its structural characteristics are: it also includes a flow distribution valve, the two ends of the No. 1 oil inlet pipe are respectively connected to the No. 1 solenoid valve and the fuel tank, the two ends of the No. 1 oil outlet pipe are respectively connected to the one-way valve and the fuel tank, the two ends of the No. 2 oil outlet pipe are respectively connected to the one-way valve and the high-precision proportional valve, and the two ends of the No. 2 oil inlet pipe are respectively connected to A high-precision proportional valve is connected to the No. 1 solenoid valve, and both ends of the No. 3 oil inlet pipe are respectively connected to the No. 1 solenoid valve and the getting-off proportional valve, the main pump is connected to the engine, the main pump and the overflow valve are both arranged on the No. 1 oil inlet pipe, the No. 1 solenoid valve is provided with a No. 1 electromagnet and a No. 2 electromagnet, the low-precision proportional three-way flow valve is arranged on the No. 2 oil inlet pipe, the No. 2 solenoid valve and the No. 3 solenoid valve are both connected to the high-precision proportional valve, the flow distribution valve is connected to a spring, the flow distribution valve is connected to the No. 1 channel and the No. 2 channel, the No. 1 channel is connected to the No. 2 solenoid valve and the No. 3 solenoid valve, the high-precision proportional valve includes a plurality of proportional valve groups, and the No. 2 channel is connected to a plurality of proportional valve groups.

[0006] Furthermore, the No. 2 solenoid valve is connected to the No. 1 actuator, and the plurality of proportional valve groups are connected to the No. 2 actuator via an action pipeline.

[0007] Furthermore, the flow distribution valve is connected to the No. 1 throttle hole, the No. 2 throttle hole, and the No. 3 throttle hole.

[0008] Furthermore, the low-precision proportional three-way flow valve and the high-precision proportional valve constitute an on-board proportional valve, the on-board proportional valve is used to control the movement of the upper part of the vehicle, and the off-board proportional valve is used to control the movement of the lower part of the vehicle.

[0009] Furthermore, the high-precision proportional valve is located behind the central rotating body, and the low-precision proportional three-way flow valve is located before the central rotating body.

[0010] Furthermore, another technical purpose of the present invention is to provide a control method for a hydraulic control system of an energy-saving aerial work vehicle.

[0011] The above technical objectives of the present invention are achieved through the following technical solutions.

[0012] A control method for a hydraulic control system of an energy-saving aerial work vehicle, characterized in that: the control method is as follows: the engine drives the main pump to operate, when the No. 1 electromagnet is energized, the hydraulic oil enters the vehicle dismounting proportional valve to work, when the No. 2 electromagnet is energized, the hydraulic oil enters the low-precision proportional three-way flow valve and then flows into the flow distribution valve to work; When the action moves to the bottom overflow valve and reaches the overflow state, the engine power is insufficient, which will cause the engine to stall. At this time, the main pump will automatically adjust the pump displacement and reduce the flow rate, so that the pump power cannot exceed the power provided by the engine to avoid the occurrence of engine stalling. When the action is in motion, the hydraulic oil passes through the low-precision proportional three-way flow valve to the flow distribution valve, and then enters the high-precision proportional valve through the second channel to work; When the small flow action is working, the opening of the low-precision proportional three-way flow valve is reduced to perform primary flow adjustment, and the excess flow returns to the oil tank. The hydraulic oil adjusted by the low-precision proportional three-way flow valve enters the high-precision proportional valve through the flow distribution valve and the No. 2 channel to drive the components to work. When a small amount of hydraulic oil exceeds the allowable range of the high-precision proportional valve action, the hydraulic oil flows through the No. 1 throttle hole, the No. 2 throttle hole and the No. 3 throttle hole to return to the oil tank. When the pressure difference before and after the No. 1 throttle hole reaches a certain value so that the sum of the No. 2 pressure point and the spring force of the spring is less than the pressure value of the No. 1 pressure point, the flow distribution valve will switch to make the excess hydraulic oil flow through the No. 1 channel, the No. 3 solenoid valve, and the one-way valve to return to the oil tank, and the excess hydraulic oil flows back to the oil tank, and the overflow valve will not overflow; When the high-precision proportional valve requires a large flow rate to work, the low-precision proportional three-way flow valve opens larger for primary flow regulation, and the high-precision proportional valve performs secondary flow regulation. The low-precision proportional three-way flow valve is closer to the main pump and the oil tank than the high-precision proportional valve, and primary speed regulation is performed there to allow excess hydraulic oil to circulate back to the oil tank from nearby.

[0013] Furthermore, the No. 1 actuator does not require high control accuracy and only needs to adjust the flow through a low-precision proportional three-way flow valve. At this time, the high-precision proportional valve does not work, and the hydraulic oil enters the No. 2 solenoid valve through the No. 1 channel and then drives the No. 1 actuator to work. At this time, the No. 3 solenoid valve needs to be energized to prevent the hydraulic oil from returning to the oil tank through the valve. The excess hydraulic oil of this action will also return to the oil tank through the low-precision proportional three-way flow valve.

[0014] Furthermore, after the proportional valve group of the high-precision proportional valve is actuated, the hydraulic oil is locked in the actuating pipeline and the No. 2 oil outlet pipe. The actuating pipeline between the proportional valve group and the No. 2 actuator is very long. In this case, there will be no action delay because the hydraulic oil has been filled in the actuating pipeline and the No. 2 oil outlet pipe in advance to avoid refilling the hydraulic oil over a long distance.

[0015] Furthermore, the flow rate required by the getting-off proportional valve is much greater than the flow rate required by the high-precision proportional valve, and the flow rates required for the actions controlled by the high-precision proportional valve are also different. Different flows are provided for each action by adjusting the engine speed, and different actions use different engine speeds.

[0016] Compared with the prior art, the present invention has the following advantages: the energy-saving aerial work vehicle hydraulic control system reduces the hydraulic oil reflux distance by arranging a low-precision proportional three-way flow valve before the central rotating body and a high-precision proportional valve and a flow distribution valve after the central rotating body, and can also adopt high and low precision control for different actions respectively.

[0017] Different engine speeds for different actions can better control energy loss and effectively save costs. The hydraulic control system uses a constant power variable pump, which can make the engine power margin smaller. Even in some extreme cases where the engine cannot move, the pump displacement can be reduced to avoid engine stalling. A one-way valve is added to the oil outlet pipe to lock the hydraulic oil in the oil outlet pipe to avoid action delays and reduce energy losses caused by repeated filling of the pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the principle of the hydraulic control system of the energy-saving aerial work vehicle according to an embodiment of the present invention.

[0019] In the figure: main pump 1, engine 2, relief valve 3, No. 1 solenoid valve 4, No. 1 electromagnet 5, No. 2 electromagnet 6, get-off proportional valve 7, low-precision proportional three-way flow valve 8, one-way valve 9, flow distribution valve 10, No. 1 pressure point 11, No. 1 throttle hole 12, No. 1 channel 13, No. 2 channel 14, No. 2 pressure point 15, spring 16, No. 2 throttle hole 17, center rotary body 18, high-precision proportional valve 19, No. 2 solenoid valve 20, No. 1 actuator 21, No. 3 solenoid valve 22, No. 3 throttle hole 23, oil tank 24, No. 1 oil inlet pipe 25, No. 1 oil outlet pipe 26, No. 2 oil inlet pipe 27, No. 3 oil inlet pipe 28, No. 2 actuator 29, proportional valve group 30, action oil pipe 31, No. 2 oil outlet pipe 32. DETAILED DESCRIPTION

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and by way of examples. The following examples are intended to explain the present invention but the present invention is not limited to the following examples.

[0021] Example

[0022] See also Figure 1As shown, it should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, if there are references to terms such as "upper", "lower", "left", "right", "middle" and "one" in this specification, they are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of their relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

[0023] The energy-saving aerial work vehicle hydraulic control system in this embodiment includes a main pump 1, an engine 2, a relief valve 3, a No. 1 solenoid valve 4, a disembarking proportional valve 7, a low-precision proportional three-way flow valve 8, a one-way valve 9, a flow distribution valve 10, a high-precision proportional valve 19, a No. 2 solenoid valve 20, a No. 3 solenoid valve 22, a fuel tank 24, a No. 1 oil inlet pipe 25, a No. 1 oil outlet pipe 26, a No. 2 oil outlet pipe 32, a No. 2 oil inlet pipe 27 and a No. 3 oil inlet pipe 28.

[0024] In this embodiment, the two ends of the No. 1 oil inlet pipe 25 are respectively connected to the No. 1 solenoid valve 4 and the oil tank 24, the two ends of the No. 1 oil outlet pipe 26 are respectively connected to the one-way valve 9 and the oil tank 24, the two ends of the No. 2 oil outlet pipe 32 are respectively connected to the one-way valve 9 and the high-precision proportional valve 19, the two ends of the No. 2 oil inlet pipe 27 are respectively connected to the high-precision proportional valve 19 and the No. 1 solenoid valve 4, the two ends of the No. 3 oil inlet pipe 28 are respectively connected to the No. 1 solenoid valve 4 and the getting-off proportional valve 7, the main pump 1 is connected to the engine 2, the main pump 1 and the overflow valve 3 are both arranged on the No. 1 oil inlet pipe 25, and the No. 1 solenoid valve 4 is provided with a No. 1 electromagnet 5 and The No. 2 solenoid 6 and the low-precision proportional three-way flow valve 8 are arranged on the No. 2 oil inlet pipe 27, the No. 2 solenoid valve 20 and the No. 3 solenoid valve 22 are both connected to the high-precision proportional valve 19, the flow distribution valve 10 is connected to the spring 16, the flow distribution valve 10 is connected to the No. 1 channel 13 and the No. 2 channel 14, the No. 1 channel 13 is connected to the No. 2 solenoid valve 20 and the No. 3 solenoid valve 22, the No. 2 channel 14 is connected to multiple proportional valve groups 30 of the high-precision proportional valve 19, the No. 2 solenoid valve 20 is connected to the No. 1 actuator 21, and the multiple proportional valve groups 30 are connected to the No. 2 actuator 29 through the action pipeline 31.

[0025] The flow distribution valve 10 in this embodiment is connected to the spring 16, the flow distribution valve 10 is connected to channel No. 13 and channel No. 2, 14, channel No. 13 is connected to solenoid valve No. 2, 20 and solenoid valve No. 3, 22, channel No. 2 is connected to each valve group of the high-precision proportional valve 19, and the flow distribution valve 10 is connected to throttling hole No. 12, throttling hole No. 2, 17 and throttling hole No. 3, 23.

[0026] The low-precision proportional three-way flow valve 8 and the high-precision proportional valve 19 in this embodiment constitute the on-board proportional valve. The on-board proportional valve is used to control the movements of the upper part of the vehicle (such as the bucket, arm, etc.), and the off-board proportional valve 7 is used to control the movements of the lower part of the vehicle (such as the hydraulic outriggers, etc.). The high-precision proportional valve 19 is located after the central rotating body 18, and the low-precision proportional three-way flow valve 8 is located before the central rotating body 18.

[0027] The control method of the hydraulic control system of the energy-saving aerial work vehicle in this embodiment is as follows: the engine 2 drives the main pump 1 to operate, when the No. 1 electromagnet 5 is energized, the hydraulic oil enters the disembarkation proportional valve 7 to work, and when the No. 2 electromagnet 6 is energized, the hydraulic oil enters the low-precision proportional three-way flow valve 8 and then flows into the flow distribution valve 10 to work.

[0028] When the action moves to the bottom overflow valve 3 and reaches the overflow state, insufficient engine power may cause engine 2 to stall. At this time, the main pump 1 will automatically adjust the pump displacement and reduce the flow rate so that the pump power cannot exceed the power provided by engine 2, thereby avoiding the occurrence of engine 2 stalling. When in action, the hydraulic oil passes through the low-precision proportional three-way flow valve 8 to the flow distribution valve 10, and then passes through the No. 2 channel 14 to enter the high-precision proportional valve 19 to work.

[0029] When the small flow action is working, the opening of the low-precision proportional three-way flow valve 8 is reduced for primary flow adjustment, and the excess flow returns to the oil tank 24. The hydraulic oil adjusted by the low-precision proportional three-way flow valve 8 enters the high-precision proportional valve 19 through the flow distribution valve 10 and the second channel 14 to drive the components to work. When a small amount of hydraulic oil exceeds the allowable range of the high-precision proportional valve 19, the hydraulic oil flows through the No. 1 throttle hole 12, the No. 2 throttle hole 17 and the No. 3 throttle hole 23 and returns to the oil tank 24. When the pressure difference before and after the No. 1 throttle hole 12 reaches a certain value so that the sum of the spring force of the No. 2 pressure point 15 and the spring 16 is less than the pressure value of the No. 1 pressure point 11, the flow distribution valve 10 will be reversed to allow the excess hydraulic oil to flow through the No. 1 channel 13, the No. 3 solenoid valve 22, and the one-way valve 9 to return to the oil tank 24. During the entire action process, the excess hydraulic oil flows back to the oil tank 24, and the overflow valve 3 will not overflow, thus achieving an energy-saving effect.

[0030] When the high-precision proportional valve 19 requires a large flow rate to work, the low-precision proportional three-way flow valve 8 opens wider for primary flow regulation, and the high-precision proportional valve 19 performs secondary flow regulation. In this way, energy saving can be achieved during operation under both large and small flow rates. The low-precision proportional three-way flow valve 8 is closer to the main pump 1 and the oil tank 24 than the high-precision proportional valve 19. Primary speed regulation is performed there, allowing excess hydraulic oil to circulate back to the oil tank 24 from nearby, which is more energy-efficient.

[0031] The No. 1 actuator 21 does not require high control accuracy and only needs to adjust the flow through the low-precision proportional three-way flow valve 8. At this time, the high-precision proportional valve 19 does not work, and the hydraulic oil enters the No. 2 solenoid valve 20 through the No. 1 channel 13 and then drives the No. 1 actuator 21 to work. At this time, the No. 3 solenoid valve 22 needs to be energized to prevent the hydraulic oil from returning to the oil tank 24 from the valve. The excess hydraulic oil of this action will also return to the oil tank 24 through the low-precision proportional three-way flow valve 8, which is relatively energy-saving.

[0032] After the proportional valve group 30 of the high-precision proportional valve 19 is actuated, the hydraulic oil is locked in the actuating pipeline 31 and the No. 2 oil outlet pipe 32. The actuating pipeline 31 between the proportional valve group 30 and the No. 2 actuator 29 is very long. In this case, there will be no action delay because the hydraulic oil has been filled in the actuating pipeline 31 and the No. 2 oil outlet pipe 32 in advance to avoid refilling of the hydraulic oil over a long distance.

[0033] In addition, the flow rate required by the getting off proportional valve 7 is much greater than the flow rate required by the high-precision proportional valve 19, and the flow rates required for the actions controlled by the high-precision proportional valve 19 are also different. By adjusting the speed of the engine 2 to provide different flow rates for each action, different actions use different engine speeds, which can save fuel.

[0034] Specifically, the engine 2 is connected to the main pump 1, the main pump 1 is connected to the No. 1 solenoid valve 4, the No. 1 solenoid valve 4 includes the No. 1 electromagnet 5 and the No. 2 electromagnet 6, when the No. 2 electromagnet 6 is energized, the hydraulic oil flows into the flow distribution valve 10 through the low-precision proportional three-way flow valve 8, and when the No. 1 electromagnet 5 is energized, the hydraulic oil enters the disembarking proportional valve 7, and there is a spring 16 on the flow distribution valve 10 to position the valve on one side, the flow distribution valve 10 is connected to the No. 2 channel 14, the No. 2 channel 14 is connected to each valve group of the high-precision proportional valve 19, the flow distribution valve 10 is also connected to the No. 1 throttle hole 12, the No. 2 throttle hole 17, and the No. 3 throttle hole 23, in addition, the flow distribution valve 10 is also connected to the No. 1 channel 13, and the No. 1 channel 13 is connected to the No. 3 solenoid valve 22 and the No. 2 solenoid valve 20.

[0035] The main pump 1 is a constant power variable displacement pump, and its power is less than that of the engine 2 to prevent the engine 2 from stalling.

[0036] The hydraulic oil from the flow distribution valve 10 usually flows into the high-precision proportional valve 19 through the second channel 14. When the flow exceeds the allowable range of the high-precision proportional valve 19, the excess flow flows out from the first channel 13.

[0037] Channel No. 1 13 connects solenoid valve No. 2 20 and solenoid valve No. 3 22 . The middle position of solenoid valve No. 3 22 is the H function. The excess flow out of channel No. 1 13 flows through the middle position H function of solenoid valve No. 3 22 and then flows back to the oil tank 24 through the one-way valve 9.

[0038] A one-way valve 9 is provided between the No. 1 oil outlet pipe 26 and the No. 2 oil outlet pipe 32, which can close the vehicle oil circuit when not in operation.

[0039] The low-precision proportional three-way flow valve 8 and the high-precision proportional valve 19 are used in conjunction with the low-precision proportional three-way flow valve 8 to perform primary flow adjustment, and excess flow directly returns to the oil tank 24. The high-precision proportional valve 19 performs fine adjustment and returns to the oil tank 24 through the method of "the hydraulic oil coming out of the flow distribution valve 10 usually flows into the high-precision proportional valve 19 through the No. 2 channel 14. When the flow exceeds the allowable range of the high-precision proportional valve 19, the excess flow flows out from the No. 1 channel 13; the No. 1 channel 13 connects the No. 2 solenoid valve 20 and the No. 3 solenoid valve 22, and the No. 3 solenoid valve 22 is in the middle position of the H function. The excess flow flowing out of the No. 1 channel 13 passes through the No. 3 solenoid valve 22 in the middle position H function and then flows back to the oil tank 24 through the one-way valve 9."

[0040] The low-precision proportional three-way flow valve 8 is closer to the main pump 1 and the oil tank 24 than the high-precision proportional valve 19. For primary speed regulation, the excess hydraulic oil can flow back to the oil tank 24 at a shorter distance, reducing energy loss.

[0041] When the action of the No. 1 actuator 21 does not require high proportional regulation, the low-precision proportional three-way flow valve 8 can be used alone to regulate the flow.

[0042] The engine 2 can adjust the speed according to the flow demand to achieve the purpose of saving fuel.

[0043] In addition, it should be noted that the shapes and names of the parts and components of the specific embodiments described in this specification may be different, and the above content described in this specification is only an example of the structure of the present invention. All equivalent changes or simple changes made based on the structure, features and principles described in the patent concept of the present invention are included in the protection scope of the patent of the present invention. Technicians in the technical field of the present invention can make various modifications or supplements to the specific embodiments described or replace them in a similar manner, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. An energy-saving aerial work vehicle hydraulic control system, comprising a main pump (1), an engine (2), a relief valve (3), a No. 1 solenoid valve (4), a disembarkation proportional valve (7), a low-precision proportional three-way flow valve (8), a one-way valve (9), a high-precision proportional valve (19), a No. 2 solenoid valve (20), a No. 3 solenoid valve (22), an oil tank (24), a No. 1 oil inlet pipe (25), a No. 1 oil outlet pipe (26), a No. 2 oil outlet pipe (32), a No. 2 oil inlet pipe (27) and a No. 3 oil inlet pipe (28), characterized in that: The vehicle further comprises a flow distribution valve (10), wherein two ends of the No. 1 oil inlet pipe (25) are respectively connected to the No. 1 solenoid valve (4) and the oil tank (24), two ends of the No. 1 oil outlet pipe (26) are respectively connected to the one-way valve (9) and the oil tank (24), two ends of the No. 2 oil outlet pipe (32) are respectively connected to the one-way valve (9) and the high-precision proportional valve (19), two ends of the No. 2 oil inlet pipe (27) are respectively connected to the high-precision proportional valve (19) and the No. 1 solenoid valve (4), two ends of the No. 3 oil inlet pipe (28) are respectively connected to the No. 1 solenoid valve (4) and the vehicle disembarking proportional valve (7), the main pump (1) is connected to the engine (2), and the main pump (1) and the overflow valve (3) are both arranged on the No. 1 oil inlet pipe (2 5), the No. 1 solenoid valve (4) is provided with a No. 1 solenoid (5) and a No. 2 solenoid (6), the low-precision proportional three-way flow valve (8) is provided on the No. 2 oil inlet pipe (27), the No. 2 solenoid valve (20) and the No. 3 solenoid valve (22) are both connected to the high-precision proportional valve (19), the flow distribution valve (10) is connected to the spring (16), the flow distribution valve (10) is connected to the No. 1 channel (13) and the No. 2 channel (14), the No. 1 channel (13) is connected to the No. 2 solenoid valve (20) and the No. 3 solenoid valve (22), the high-precision proportional valve (19) includes a plurality of proportional valve groups (30), and the No. 2 channel (14) is connected to a plurality of proportional valve groups (30).

2. The energy-saving hydraulic control system for aerial work vehicles according to claim 1 is characterized in that: The second solenoid valve (20) is connected to the first actuator (21), and the plurality of proportional valve groups (30) are connected to the second actuator (29) via an action pipeline (31).

3. The energy-saving hydraulic control system for aerial work vehicles according to claim 1 is characterized in that: The flow distribution valve (10) is connected to the first throttle hole (12), the second throttle hole (17), and the third throttle hole (23).

4. The energy-saving hydraulic control system for aerial work vehicles according to claim 1 is characterized in that: The low-precision proportional three-way flow valve (8) and the high-precision proportional valve (19) constitute an on-board proportional valve, the on-board proportional valve is used to control the movement of the upper part of the vehicle, and the off-board proportional valve (7) is used to control the movement of the lower part of the vehicle.

5. The energy-saving hydraulic control system for aerial work vehicles according to claim 1 is characterized in that: The high-precision proportional valve (19) is located behind the central rotating body (18), and the low-precision proportional three-way flow valve (8) is located before the central rotating body (18).

6. A control method for an energy-saving aerial work vehicle hydraulic control system according to any one of claims 1 to 5, characterized in that: The control method is as follows: the engine (2) drives the main pump (1) to operate, when the No. 1 electromagnet (5) is energized, the hydraulic oil enters the vehicle dismounting proportional valve (7) to operate, and when the No. 2 electromagnet (6) is energized, the hydraulic oil enters the low-precision proportional three-way flow valve (8) and then flows into the flow distribution valve (10) to operate; When the action moves to the bottom overflow valve (3) and reaches the overflow state, the engine power is insufficient, which will cause the engine (2) to stall. At this time, the main pump (1) will automatically adjust the pump displacement and reduce the flow rate so that the pump power does not exceed the power provided by the engine (2) to avoid the engine (2) stalling. When the action is in progress, the hydraulic oil passes through the low-precision proportional three-way flow valve (8) to the flow distribution valve (10), and then passes through the second channel (14) to enter the high-precision proportional valve (19) to work; When the low-flow action is working, the opening of the low-precision proportional three-way flow valve (8) is reduced to perform primary flow adjustment, and the excess flow returns to the oil tank (24). The hydraulic oil adjusted by the low-precision proportional three-way flow valve (8) enters the high-precision proportional valve (19) through the flow distribution valve (10) and the second channel (14) to drive the components to work. When a small amount of hydraulic oil exceeds the allowable range of the high-precision proportional valve (19), the hydraulic oil flows through the first throttle hole (12) and the second throttle hole (17). When the pressure difference before and after the No. 1 throttle hole (12) reaches a certain value so that the sum of the spring force of the No. 2 pressure point (15) and the spring (16) is less than the pressure value of the No. 1 pressure point (11), the flow distribution valve (10) will be switched to allow the excess hydraulic oil to flow through the No. 1 channel (13), the No. 3 solenoid valve (22), and the one-way valve (9) back to the oil tank (24), and the excess hydraulic oil will flow back to the oil tank (24) without overflowing the overflow valve (3); When the high-precision proportional valve (19) requires a large flow rate to work, the low-precision proportional three-way flow valve (8) opens wider to perform primary flow regulation, and the high-precision proportional valve (19) performs secondary flow regulation. The low-precision proportional three-way flow valve (8) is closer to the main pump (1) and the oil tank (24) than the high-precision proportional valve (19), and primary speed regulation is performed there, allowing excess hydraulic oil to circulate back to the oil tank (24) from a nearby location.

7. The control method of the hydraulic control system of the energy-saving aerial work vehicle according to claim 6 is characterized in that: The control accuracy requirement of the No. 1 actuator (21) is not high, and the flow rate only needs to be adjusted through the low-precision proportional three-way flow valve (8). At this time, the high-precision proportional valve (19) does not work, and the hydraulic oil enters the No. 2 solenoid valve (20) through the No. 1 channel (13) and then drives the No. 1 actuator (21) to work. At this time, the No. 3 solenoid valve (22) needs to be energized to prevent the hydraulic oil from returning to the oil tank (24) from the valve. The excess hydraulic oil caused by this action will also return to the oil tank (24) through the low-precision proportional three-way flow valve (8).

8. The control method of the hydraulic control system of the energy-saving aerial work vehicle according to claim 6 is characterized in that: When the proportional valve group (30) of the high-precision proportional valve (19) is actuated, the hydraulic oil is locked in the actuating pipeline (31) and the second oil outlet pipe (32). The actuating pipeline (31) between the proportional valve group (30) and the second actuator (29) is very long. In this case, there will be no actuation delay because the hydraulic oil has been pre-filled in the actuating pipeline (31) and the second oil outlet pipe (32) to avoid refilling of the hydraulic oil over a long distance.

9. The control method of the hydraulic control system of the energy-saving aerial work vehicle according to claim 6 is characterized in that: The flow rate required by the disembarking proportional valve (7) is much greater than the flow rate required by the high-precision proportional valve (19), and the flow rates required by the actions controlled by the high-precision proportional valve (19) are also different. By adjusting the speed of the engine (2), different flows are provided for each action, and different actions use different engine speeds.

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