A hydraulic system of an adaptive variable pump and a fixed displacement pump

Abstract

The application discloses a hydraulic system of a self-adaptive variable pump and a quantitative pump, which comprises a quantitative pump, a variable pump, a valve group I, a valve group II, a valve group III, the valve group I comprises a three-way flow valve, a shuttle valve and an electromagnetic reversing valve I, and a P1 port of the valve group I is connected with an oil way of a P1 port through a one-way valve; a 1 port of the three-way flow valve is connected with the oil way of the P1 port of the valve group I, a 2 port is connected with a T port, a 3 port is connected with a 3 port of the electromagnetic reversing valve I, a 1 port of the flow valve is connected with a 2 port of the shuttle valve, a 1 port of the electromagnetic reversing valve I is connected with an LS port of the valve group I, a 2 port is connected with the 2 port of the shuttle valve, a 1 port of the shuttle valve is connected with an LS2 port of the valve group I, and a 3 port is connected with an LS1 port of the valve group I; the valve group II comprises a plurality of parallel proportional reversing valves II, and the valve group III comprises a plurality of parallel proportional reversing valves II. The hydraulic system is equipped with the quantitative pump and the variable pump, can match various power sources, can be switched flexibly, improves the adaptability of the aerial work platform, is energy-saving and environment-friendly, and is convenient to match.

Description

Technical Field

[0001] This invention relates to the field of engineering machinery technology, specifically to a hydraulic system with an adaptive variable pump and a fixed displacement pump. Background Technology

[0002] Aerial work platforms or aerial work vehicle systems are typically powered by diesel, AC mains, or batteries. Diesel power provides high power but is not environmentally friendly; AC mains power usually requires a power source and has limitations; battery power is environmentally friendly and adaptable to various locations, but batteries (storage batteries or lithium batteries) are bulky, difficult to install, and have limited continuous operating time. To save space, increase continuous operating time, save energy and protect the environment, while meeting the various working conditions of the work vehicle, such as traveling, indoor, outdoor, and off-road, multiple power sources are usually configured. Battery and AC mains power are matched with small-power motors, which in turn are matched with small-power fixed displacement pumps, providing sufficient flow for stable operation. Traveling, outdoor, and off-road operations require higher power, typically using high-power diesel or gasoline engines to drive variable displacement pumps. However, general hydraulic systems cannot accommodate both fixed displacement and variable displacement pumps, therefore, the hydraulic system needs to be optimized to solve these problems. Summary of the Invention

[0003] The purpose of this invention is to provide a hydraulic system with an adaptive variable pump and a fixed pump. The hydraulic system is equipped with both a fixed pump and a variable pump, and can be flexibly switched according to work needs, which can effectively enhance the driving capability and environmental adaptability of the aerial work platform vehicle.

[0004] To achieve the above objectives, the present invention provides a hydraulic system for an adaptive variable pump and a fixed displacement pump, comprising a fixed displacement pump, a variable displacement pump, valve group I, valve group II, and valve group III; wherein valve group I includes a check valve, a three-way flow valve, a shuttle valve, and a solenoid directional valve I, and the oil circuits of port P and port P1 of valve group I are connected through the check valve; port 1 of the three-way flow valve is connected to the oil circuit of port P1 of valve group I, port 2 is connected to port T of valve group I, and port 3 is connected to port 3 of solenoid directional valve I; port 1 of the flow valve is connected to port 2 of the shuttle valve; port 1 of the solenoid directional valve I is connected to port LS of valve group I, and port 2 is connected to port 2 of the shuttle valve; port 1 of the shuttle valve is connected to port LS2 of valve group I, and port 3 is connected to port LS1 of valve group I; valve group II includes multiple parallel proportional directional valves II; valve group III includes a solenoid directional valve II and multiple parallel proportional directional valves II.

[0005] Furthermore, the outlet of the variable pump is connected to the P port of valve group III via a filter; the A1 port of the solenoid directional valve II is connected to the P port of valve group II, and the P2 port of valve group III is connected to the P port of the proportional directional valve; the outlet of the fixed displacement pump is connected to the P1 port of valve group I, and the LS port of valve group I is connected to the LS port of the variable pump; the 2 port of valve group ILS is connected to the LS port of valve group III; and the LS1 port of valve group I is connected to the LS port of valve group II.

[0006] Furthermore, the valve assembly I also includes a flow valve, wherein port 1 of the flow valve is connected to port 2 of the shuttle valve, and port 2 is connected to port 2 of the three-way flow valve and the oil outlet T, respectively.

[0007] Furthermore, a damping plug is provided in the oil line between port 1 of the electromagnetic directional valve I and port ILS of the valve group; port 3 of the three-way flow valve is connected to port 3 of the electromagnetic directional valve I through the damping plug.

[0008] Furthermore, the valve group II also includes an accumulator and a damper, with one path of the damper connected to the LS port of the valve group III and the other path connected to the accumulator.

[0009] Furthermore, the valve assembly III also includes an overflow valve, with port 2 of the overflow valve connected to port P of the valve assembly III and port 1 connected to port T of the proportional directional valve II.

[0010] The beneficial effects of this invention are:

[0011] (1) The present invention configures a hydraulic system on the aerial work vehicle, which can satisfy both the proportional speed regulation of the fixed pump and the proportional speed regulation of the variable pump, thereby enhancing the adaptability of the system;

[0012] (2) Through the optimization and improvement of the hydraulic system, the aerial work platform can be matched with a variety of power sources (battery power, mains power, diesel engine and gasoline engine) and can be flexibly switched to meet the needs of long-term work.

[0013] (3) Multiple shuttle valves can be installed in valve group I to match more proportional directional valves. The control pressure of the proportional valve is transmitted to the variable pump or three-way flow valve through the shuttle valve to achieve speed regulation, thereby enhancing the scalability of the system.

[0014] (4) Multiple dampers are set in valve group I, and their size can be matched according to different flow rates to increase the stability of control;

[0015] (5) The electromagnetic reversing valve I in valve group I is used to switch the control oil circuit when the variable pump and the fixed pump are working, so as to achieve interlocking, that is, the variable pump and the fixed pump cannot work at the same time.

[0016] (6) A flow valve is installed in valve group I to relieve the pressure at the control port, ensuring that the variable pump swashplate and three-way flow valve are reset when not in operation, thus increasing service life. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the proportional speed control hydraulic system of the adaptive variable pump and fixed displacement pump of the present invention;

[0018] Figure 2 This is a schematic diagram of the valve assembly I of this hydraulic system.

[0019] Figure 3 This is the structural schematic diagram of valve group II of this hydraulic system;

[0020] Figure 4 This is the structural schematic diagram of valve group III in this hydraulic system;

[0021] In the diagram, 1-oil tank; 2-return oil filter; 3-fixed displacement pump; 4-variable displacement pump; 5-check valve I; 6-filter I; 7-valve assembly I; 8-valve assembly II; 9-valve assembly III; 10-check valve II; 11-damping plug I; 12-three-way flow valve; 13-flow valve; 14-damping plug II; 15-shuttle valve; 16-solenoid directional valve I; 17-damper; 18-accumulator; 19-relief valve I; 20-filter II; 21-pressure reducing valve; 22-proportional directional valve I; 23-relief valve II; 24-solenoid directional valve II; 25-relief valve III; 26-proportional directional valve II. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] like Figure 1-2As shown, a hydraulic system with an adaptive variable displacement pump and a fixed displacement pump includes a fixed displacement pump 3, a variable displacement pump 4, valve group I7, valve group II8, and valve group III9. The oil outlet of the return oil filter 2, the oil inlet of the fixed displacement pump 3, and the oil inlet of the variable displacement pump 4 are respectively connected to the oil tank 1. Valve group I7 includes a check valve 10, a three-way flow valve 12, a shuttle valve 15, and a solenoid directional valve I16. The P port of valve group I7 is connected to the P1 port in the oil circuit. Port 1 of the three-way flow valve 12 is connected to the oil circuit from P to P1 of valve group I7, port 2 is connected to port 2 of shuttle valve 15, and port 3 is connected to port 3 of solenoid directional valve I16. Port 1 of the flow valve 13 is connected to port 2 of shuttle valve 15. Port 1 of the solenoid directional valve I16 is connected to port LS of valve group I7, and port 2 is connected to port 2 of shuttle valve 15. Port 1 of the shuttle valve 15 is connected to port LS2 of valve group I7, and port 1 is connected to port LS1 of valve group I7. Valve assembly I7 also includes a flow valve 13. Flow valve 13's port 11 is connected to port 2 of shuttle valve 16, and port 2 is connected to port 2 of three-way flow valve 12 and the oil outlet T, respectively. Check valve II10 is located on the oil line from P to P1 of valve assembly I7. Port 1 of check valve II10 is connected to port P1 of valve assembly I7, and port 2 is connected to port P of valve assembly I7. Check valve II10 prevents the pressure oil from variable pump 4 from communicating with port P1. A damping plug 14 is installed on the oil line between port 1 of solenoid directional valve I16 and port LS of valve assembly I7. Port 3 of three-way flow valve 12 is connected to port 3 of solenoid directional valve I16 through damping plug 11. Damping plugs I11 and II14 are used to regulate pressure fluctuations in the control oil line and prevent excessive speed changes. Solenoid directional valve I16 is only energized when the fixed displacement pump is working, allowing the oil from proportional valve LS to communicate with port 3 of three-way flow valve 12, thus achieving proportional speed regulation. The outlet of variable pump 4 is connected to port P of valve group III9 via check valve I5 and filter I6. Port A1 of solenoid directional valve II24 is connected to port P of valve group II8, and port P2 of valve group III9 is ​​connected to port P of proportional directional valve 26. The outlet of fixed displacement pump 3 is connected to port P1 of valve group I7, and port LS of valve group I7 is connected to port LS of variable pump 4. Port LS2 of valve group I7 is connected to port LS of valve group III9, and port LS1 of valve group I7 is connected to port LS of valve group II8.

[0024] like Figure 3 As shown, valve assembly II8 includes a damper 17, an accumulator 18, and multiple parallel proportional directional valves II22. Valve assembly II8 also includes a damper 17 connected in one path to the LS port of valve assembly III9, and another path connected to the accumulator 18. In valve assembly II8, the filter II20 filters the hydraulic oil in the control circuit to prevent contaminants from clogging the control circuit and affecting directional switching. The pressure reducing valve 21 is used to ensure the pressure in the control circuit, guaranteeing smooth directional switching.

[0025] like Figure 4As shown, valve group III9 includes solenoid directional valve II24, relief valve III25 and multiple parallel proportional directional valves II26. Port 2 of relief valve III25 is connected to port P of valve group III9, and port 1 is connected to port T of proportional directional valve II6.

[0026] In this system, the relief valve III25 in valve group III9 controls the maximum pressure of the system, the relief valve II23 controls the maximum pressure of the proportional directional valve 26, and the relief valve I19 controls the maximum pressure of the proportional directional valve 22.

[0027] The accumulator 18 and damper 17 of valve group I8 both play the role of regulating and controlling the pressure fluctuation of the oil circuit and preventing the movement from becoming unstable due to rapid changes in flow.

[0028] The working principle of this hydraulic system is as follows:

[0029] When the variable pump 4 is working, the pressurized oil enters the valve group III9 through the filter I6. When the electromagnet a of the solenoid directional valve II24 is energized, the proportional directional valve II26 is working. The control pressure is transmitted to port 1 of the shuttle valve 15 through the LS port of the valve group III9. Ports 1 and 2 of the shuttle valve 15 are connected. The solenoid directional valve I16 is not energized. The control oil flows from port 2 of the shuttle valve 15 to port 2 of the solenoid directional valve I16, port 1 of the solenoid directional valve I16, and the LS port of the valve group I7 into the LS port of the variable pump 4. The output flow rate is changed by the pressure change at the LS port, thereby adjusting the speed.

[0030] When the electromagnet b of the solenoid directional valve II24 is energized, pressurized oil enters valve group II8 via oil pipe through valve group II A1. When the proportional directional valve I22 is working, the control oil circuit is transmitted to port 3 of shuttle valve 15 through port LS of valve group II8. Port 3 and port 2 of shuttle valve 15 are connected. The solenoid directional valve I16 is not energized. The control oil flows from port 2 of shuttle valve 15 to port 2 of solenoid directional valve I16. Port 1 of solenoid directional valve I16 and port LS of valve group I7 enter port LS of variable pump 4 through oil pipe. The output flow rate is changed by the pressure change at port LS, thereby regulating the speed.

[0031] When the variable pump 4 stops working, the pressure at the LS control port is relieved to the T port through the flow valve 13 to prevent the pressure at the LS port from not being relieved, which would cause the swashplate inside the variable pump to not reset and affect the life of the variable pump.

[0032] When the fixed displacement pump 3 is working, the pressurized oil enters directly into port P1 of valve group I7 through the pipeline. Port P1 is connected to port 1 of check valve 10 and port 1 of three-way flow valve 12. When proportional directional valve I22 or proportional directional valve II26 is working, port LS of valve group II8 or valve group III9 enters port 2 of solenoid directional valve I16 through shuttle valve 15. Solenoid directional valve I16 is energized, and control oil flows from port 2 to port 3 of solenoid directional valve I16. Port 3 of solenoid directional valve I16 then... The damping plug I11 is connected to port 3 of the three-way flow valve 12. When the pressure at port LS of the proportional directional valve I22 or the proportional directional valve 26 changes, the pressure at port 3 of the three-way flow valve 12 changes with the pressure at port LS, thereby regulating the flow rate from port 1 to port 3 of the three-way flow valve 12. The flow rate from port P1 to port P of valve group I7 also changes with the flow rate from port 1 to port 3 of the three-way flow valve 12, thereby regulating the flow rate of the proportional directional valves I22 and II26.

[0033] When the metering pump 3 stops working, the pressure at the LS control port is relieved to the T port through the flow valve 13, the three-way flow valve 12 is normally open, and the system is unloaded.

[0034] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited thereto. Various changes that can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention are all within the protection scope of the claims of the present invention.

Claims

1. A hydraulic system for an adaptive variable pump and a fixed displacement pump, characterized in that, Includes a fixed displacement pump, a variable displacement pump, valve group I, valve group II, and valve group III; The valve assembly I includes a check valve, a three-way flow valve, a flow valve, a shuttle valve, and a solenoid directional valve I; The P port and P1 port oil circuit of the valve group I are connected by a check valve; the 1 port of the three-way flow valve is connected to the oil circuit of the P1 port of the valve group I, the 2 port is connected to the T port of the valve group I, and the 3 port is connected to the 3 port of the solenoid directional valve I. One port of the flow valve is connected to the second port of the shuttle valve, and the second port is connected to the second port of the three-way flow valve and the oil outlet T, respectively. The electromagnetic reversing valve I has port 1 connected to port LS of valve group I and port 2 connected to port 2 of shuttle valve; the shuttle valve has port 1 connected to port LS2 of valve group I and port 3 connected to port LS1 of valve group I. Valve group II includes multiple proportional directional valves I connected in parallel; valve group III includes electromagnetic directional valve II and multiple proportional directional valves II connected in parallel. The outlet of the variable pump is connected to the P port of valve group III via a filter; the A1 port of the solenoid directional valve II of valve group III is connected to the P port of valve group II, and the P2 port of valve group III is connected to the P port of the proportional directional valve II; the outlet of the fixed displacement pump is connected to the P1 port of valve group I, and the LS port of valve group I is connected to the LS port of the variable pump; the LS2 port of valve group I is connected to the LS port of valve group III; and the LS1 port of valve group I is connected to the LS port of valve group II.

2. The hydraulic system of an adaptive variable pump and a fixed displacement pump according to claim 1, characterized in that, A damping plug II is provided in the oil line between port 1 of the electromagnetic directional valve I and port LS of the valve group I; port 3 of the three-way flow valve is connected to port 3 of the electromagnetic directional valve I through damping plug I.

3. The hydraulic system of an adaptive variable pump and a fixed displacement pump according to claim 2, characterized in that, The valve group II also includes an accumulator and a damper. One path of the damper is connected to the LS port of the valve group II, and the other path is connected to the accumulator.

4. The hydraulic system of an adaptive variable pump and a fixed displacement pump according to claim 3, characterized in that, The valve group III also includes a relief valve, with port 2 of the relief valve connected to port P of the valve group III and port 1 connected to port T of the proportional directional valve II.

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