Environmental protection and energy-saving potential energy recovery and utilization system for lifting machinery under multiple working conditions

Abstract

The present invention discloses an environmentally friendly and energy-saving multi-condition potential energy recovery and utilization system for hoisting machinery, which includes a main circuit and a recovery circuit. The main circuit is composed of an oil tank I, a fixed-displacement pump, a three-position six-way directional control valve, and a pressure-compensated flow control valve. The oil tank I is connected with a check valve I through a pipeline. The check valve I is connected with the fixed-displacement pump through a pipeline. A motor for driving the fixed-displacement pump is provided on one side of the fixed-displacement pump. The outlet end of the fixed-displacement pump is respectively connected with a relief valve and a check valve II through pipelines. A two-position two-way solenoid directional control valve is provided at the oil discharge port of the relief valve. The overflow port of the relief valve and the outlet end of the two-position two-way solenoid directional control valve are both connected with the oil tank I through pipelines. The outlet end of the check valve II is respectively connected with a three-position six-way solenoid directional control valve and a three-position three-way directional control valve I. The present invention has a large power density and low cost, absorbs the fluctuations during the braking process to a great extent, and effectively improves the energy utilization rate.

Description

Technical Field

[0001] The invention belongs to the technical field of hydraulic technology for lifting equipment, and particularly relates to an environmental protection and energy-saving multi-condition potential energy recovery and utilization system for lifting machinery. Background Art

[0002] During the operation of lifting machinery, the boom needs to be frequently lifted and lowered. How to recover and utilize the energy wasted during the lifting and lowering process is the focus of research. Currently, the mainstream energy recovery methods mostly adopt electrical and hydraulic types. The main energy storage components of the electrical type are supercapacitors and storage batteries, and the advantages are large energy storage density and small volume. Guan Che aimed at the boom system of a pure electric drive hydraulic excavator, using a supercapacitor as the energy storage device, and at the same time introducing a DC / DC to stabilize the bus voltage between the supercapacitor and the motor. The results show that compared with the traditional electric drive excavator, 29% energy saving is achieved. However, the electrical recovery conversion link is numerous, and multiple conversions reduce the overall efficiency. Summary of the Invention

[0003] The purpose of the invention is to overcome the above deficiencies, thereby providing a multi-condition potential energy recovery and utilization system for lifting machinery with high power density, environmental protection and energy saving, low cost, and effectively improving the energy utilization rate.

[0004] To achieve the above design objectives, the technical solution adopted by the present invention is: an environmental protection and energy-saving multi-condition potential energy recovery and utilization system for a hoisting machine, including a main circuit and a recovery circuit. The main circuit consists of a fuel tank I, a fixed-displacement pump, a three-position six-way solenoid directional control valve, and a pressure-compensated flow control valve. The fuel tank I is connected to a check valve I through a pipeline, the check valve I is connected to a fixed-displacement pump through a pipeline, and a motor for driving the fixed-displacement pump is provided on one side of the fixed-displacement pump. The outlet end of the fixed-displacement pump is respectively connected to a relief valve and a check valve II through pipelines. A two-position two-way solenoid directional control valve is provided at the oil discharge port of the relief valve, and the overflow port of the relief valve and the outlet end of the two-position two-way solenoid directional control valve are both connected to the fuel tank I through pipelines. The outlet end of the check valve II is respectively connected to a three-position six-way solenoid directional control valve and a three-position three-way solenoid directional control valve I through pipelines. The three-position six-way solenoid directional control valve is connected to a solenoid directional control valve through a pipeline. One path in the solenoid directional control valve is connected to a pressure-compensated flow control valve through a pipeline, and the pressure-compensated flow control valve is connected to a hydraulic cylinder through a pipeline. The recovery circuit consists of a fuel tank II, a fuel tank III, a three-position three-way solenoid directional control valve II, a fixed-displacement motor, a fixed-displacement pump II, an energy release control valve I, an energy release control valve II, a high-pressure energy accumulator, and a low-pressure energy accumulator. The fuel tank II is respectively connected to a fixed-displacement pump II and a fixed-displacement motor through pipelines. The fixed-displacement pump II is connected to a check valve III through a pipeline, the check valve III is connected to a three-position three-way solenoid directional control valve II through a pipeline, and a relief valve II is connected to the pipeline between the check valve III and the three-position three-way solenoid directional control valve II. The overflow port of the relief valve II is connected to the fuel tank III through a pipeline. The three-position three-way solenoid directional control valve II is respectively connected to a check valve IV and a check valve V through pipelines. The check valve IV is respectively connected to a high-pressure energy accumulator and an energy release control valve I through pipelines. The check valve V is respectively connected to a low-pressure energy accumulator and an energy release control valve II through pipelines.

[0005] The fixed-displacement motor and the fixed-displacement pump II provided in the recovery circuit are connected in an interconnected manner.

[0006] The fixed-displacement motor in the recovery circuit is interconnected with the solenoid directional control valve in the main circuit through a pipeline.

[0007] On the pipelines where the three-position three-way solenoid directional control valve II in the recovery circuit is respectively connected to the check valve IV and the check valve V, another pipeline is respectively interconnected with the three-position three-way solenoid directional control valve I in the main circuit.

[0008] On the pipeline between the check valve I and the fixed-displacement pump in the main circuit, another pipeline is connected to the energy release control valve I in the recovery circuit through a check valve VI, and then connected to the energy release control valve II in the recovery circuit through a check valve VII.

[0009] Advantages of the present invention: Compared with the traditional potential energy recovery system, this system has no overflow loss, can realize the recovery and utilization of potential energy, and is environmentally friendly and energy-saving. The energy stored in the system can reduce the loading power of the main engine, increase the sustainable life of the engine, improve the heat generation situation, and effectively solve the problem of difficult heat balance in construction machinery; this system has universality and can be applied as a separate recovery unit to various lifting machinery other than excavators without affecting the operation experience of operators, with strong versatility. The present invention has a large power density and low cost, can largely absorb the fluctuations during the braking process, and effectively improves the energy utilization rate. Brief Description of the Drawings

[0010] Figure 1 It is a schematic diagram of the principle structure of a multi-condition potential energy recovery and utilization system of the present invention. Detailed Embodiments

[0011] The following will describe the detailed embodiments of the present invention with reference to the drawings. As Figure 1Shown: An environmentally friendly and energy-saving multi-condition potential energy recovery and utilization system for a crane, including a main circuit and a recovery circuit. The main circuit consists of an oil tank I 4, a fixed-displacement pump 1, a three-position six-way solenoid directional valve 5, and a pressure-compensated flow control valve 7. The oil tank I 4 is connected to a check valve I 27 through a pipeline, the check valve I 27 is connected to the fixed-displacement pump 1 through a pipeline, a motor 2 for driving the fixed-displacement pump 1 is provided on one side of the fixed-displacement pump 1, the outlet end of the fixed-displacement pump 1 is respectively connected to a relief valve 3 and a check valve II 23 through pipelines, a two-position two-way solenoid directional valve 26 is provided at the oil discharge port of the relief valve 3, the overflow port of the relief valve 3 and the outlet end of the two-position two-way solenoid directional valve 26 are both connected to the oil tank I 4 through pipelines, the outlet end of the check valve II 23 is respectively connected to a three-position six-way solenoid directional valve 5 and a three-position three-way solenoid directional valve I 24 through pipelines, the three-position six-way solenoid directional valve 5 is connected to a solenoid directional valve 6 through a pipeline, one path in the solenoid directional valve 6 is connected to a pressure-compensated flow control valve 7 through a pipeline, the pressure-compensated flow control valve 7 is connected to a hydraulic cylinder 8 through a pipeline. The recovery circuit consists of an oil tank II 22, an oil tank III, a three-position three-way solenoid directional valve II 15, a fixed-displacement motor 20, a fixed-displacement pump II 21, an energy release control valve I 13, an energy release control valve II 14, a high-pressure accumulator 9, and a low-pressure accumulator 10. The oil tank II 22 is respectively connected to the fixed-displacement pump II 21 and the fixed-displacement motor 20 through pipelines, the fixed-displacement pump II 21 is connected to a check valve III 19 through a pipeline, the check valve III 19 is connected to a three-position three-way solenoid directional valve II 15 through a pipeline, a relief valve II 18 is connected to the pipeline between the check valve III 19 and the three-position three-way solenoid directional valve II 15, the overflow port of the relief valve II is connected to the oil tank III 25 through a pipeline, the three-position three-way solenoid directional valve II 15 is respectively connected to a check valve IV 11 and a check valve V 12 through pipelines, the check valve IV 11 is respectively connected to the high-pressure accumulator 9 and the energy release control valve I 13 through pipelines, and the check valve V 12 is respectively connected to the low-pressure accumulator 10 and the energy release control valve II 14 through pipelines.

[0012] The fixed-displacement motor 20 and the fixed-displacement pump II 21 provided in the recovery circuit are connected in an interconnected manner.

[0013] The fixed-displacement motor 20 in the recovery circuit is interconnected with the solenoid directional valve 6 in the main circuit through a pipeline.

[0014] On the pipelines where the three-position three-way solenoid directional valve II 15 in the recovery circuit is respectively connected to the check valve IV 11 and the check valve V 12, they are both interconnected with the three-position three-way solenoid directional valve I 24 in the main circuit through another pipeline.

[0015] On the oil pipe between the check valve I 27 and the fixed displacement pump 1 in the main circuit, another oil pipe is connected to the energy release control valve I 13 in the recovery circuit through the check valve VI 17, and then connected to the energy release control valve II 14 in the recovery circuit through the check valve VII 16.

[0016] When the present invention is in use: taking the boom hydraulic system of a certain model forklift truck as an example, under normal lifting conditions, 1YA of the three-position six-way solenoid directional valve 5 is powered on, and the pressure oil of the oil pump passes through the check valve II 23, the left position of the three-position six-way solenoid directional valve 5, the solenoid directional valve 6, and the pressure compensated flow control valve 7 and reaches the hydraulic cylinder 8. When descending, under the action of the self-weight of the fork mechanical parts fixedly connected to the hydraulic cylinder 8 and the load, according to the feedback of the pressure sensor, if the system determines it is the light load descending stage, 3YA of the solenoid directional valve 6 and 9YA of the three-position three-way solenoid directional valve II 15 are powered on, and the oil in the hydraulic cylinder 8 passes through the pressure compensated flow control valve 7, the right position of the solenoid directional valve 6, the fixed displacement motor 20, the fixed displacement pump II 21, and the check valve III 19, and finally fills the low-pressure accumulator 10 through the three-position three-way solenoid directional valve II 15. If the system determines it is the heavy load descending stage, 3YA of the solenoid directional valve 6 and 8YA of the three-position three-way solenoid directional valve II 15 are powered on, and the oil in the hydraulic cylinder 8 passes through the pressure compensated flow control valve 7, the solenoid directional valve 6, the fixed displacement motor 20, and the fixed displacement pump II 21 to fill the high-pressure accumulator 9. During the recovery process, 10YA of the two-position two-way solenoid directional valve 26 is powered on, and the motor 2 unloads. During the energy-saving ascending stage, if the pressure of the hydraulic cylinder 8 is determined to be light load by the pressure sensor, 7YA of the energy release control valve II 14 is powered on, and the low-pressure accumulator 10 releases the hydraulic energy in the low-pressure energy recovery stage. The oil passes through the energy release control valve II 14, the check valve VII 16, and the check valve VI 17 and is connected to the suction port of the fixed displacement pump 1, and enters the hydraulic cylinder 8 through the pressure compensated flow control valve 7 to push the piston to rise. If it is a heavy load, 6YA of the energy release control valve I 13 is powered on, then the high-pressure accumulator 10 releases the hydraulic energy recovered during the heavy load descent, and the oil passes through the energy release control valve I 13 and the check valve VI 17 and is connected to the suction port of the fixed displacement pump 1 to supply oil to the oil cylinder. During the locking and pressure maintaining stage, the three-position six-way directional valve 5 remains in the middle position. At this time, the hydraulic cylinder 8 is in the locked state. According to the feedback of the pressure sensor, it is judged whether the low-pressure accumulator 9 and the high-pressure accumulator 10 need to be filled with liquid. If the pressure is insufficient to pre-charge the gas pressure, the fixed displacement pump 1, the three-position three-way solenoid directional valve I 24, the check valve IV 11 or the check valve V 12 can be used to fill the accumulator with liquid respectively to ensure the stability of the energy recovery process. The recovery principle of this system: during the descent of materials with different loads, the potential energy of the self-weight of other mechanical parts and the weight of the materials is converted into hydraulic energy, and the energy is stored in the accumulator through the coaxial structure of the motor-pump unit; during the ascending stage, the pressure energy in the accumulator is released to assist the main circuit in lifting the hydraulic cylinder, reducing the power consumption of the motor, and achieving the purpose of environmental protection and energy saving.

Claims

1. An environmentally friendly and energy-saving multi-condition potential energy recovery and utilization system for hoisting machinery, characterized in that: It includes a main circuit and a recovery circuit. The main circuit consists of oil tank Ⅰ, a fixed-displacement pump, a three-position six-way solenoid directional control valve, and a pressure-compensated flow control valve. Oil tank Ⅰ is connected to a check valve Ⅰ through a pipeline. The check valve Ⅰ is connected to the fixed-displacement pump through a pipeline. A motor for driving the fixed-displacement pump is provided on one side of the fixed-displacement pump. The outlet end of the fixed-displacement pump is respectively connected to a relief valve and a check valve Ⅱ through pipelines. A two-position two-way solenoid directional control valve is provided at the oil discharge port of the relief valve. The overflow port of the relief valve and the outlet end of the two-position two-way solenoid directional control valve are both connected to oil tank Ⅰ through pipelines. The outlet end of the check valve Ⅱ is respectively connected to a three-position six-way solenoid directional control valve and a three-position three-way solenoid directional control valve Ⅰ through pipelines. The three-position six-way solenoid directional control valve is connected to a solenoid directional control valve through a pipeline. One path in the solenoid directional control valve is connected to a pressure-compensated flow control valve through a pipeline. The pressure-compensated flow control valve is connected to a hydraulic cylinder through a pipeline. The recovery circuit consists of oil tank Ⅱ, oil tank Ⅲ, a three-position three-way solenoid directional control valve Ⅱ, a fixed-displacement motor, a fixed-displacement pump Ⅱ, an energy release control valve Ⅰ, an energy release control valve Ⅱ, a high-pressure accumulator, and a low-pressure accumulator. Oil tank Ⅱ is respectively connected to the fixed-displacement pump Ⅱ and the fixed-displacement motor through pipelines. The fixed-displacement pump Ⅱ is connected to a check valve Ⅲ through a pipeline. The check valve Ⅲ is connected to the three-position three-way solenoid directional control valve Ⅱ through a pipeline. A relief valve Ⅱ is connected to the pipeline between the check valve Ⅲ and the three-position three-way solenoid directional control valve Ⅱ. The overflow port of the relief valve Ⅱ is connected to oil tank Ⅲ through a pipeline. The three-position three-way solenoid directional control valve Ⅱ is respectively connected to a check valve Ⅳ and a check valve Ⅴ through pipelines. The check valve Ⅳ is respectively connected to the high-pressure accumulator and the energy release control valve Ⅰ through pipelines. The check valve Ⅴ is respectively connected to the low-pressure accumulator and the energy release control valve Ⅱ through pipelines. The pipelines where the three-position three-way solenoid directional control valve Ⅱ in the recovery circuit is respectively connected to the check valve Ⅳ and the check valve Ⅴ are both interconnected with the three-position three-way solenoid directional control valve Ⅰ in the main circuit through another pipeline.

2. The environmentally friendly and energy-saving multi-condition potential energy recovery and utilization system for a hoisting machine according to claim 1, characterized in that: The fixed-displacement motor and the fixed-displacement pump Ⅱ provided in the recovery circuit are connected in an interconnected manner.

3. The environmentally friendly and energy-saving multi-condition potential energy recovery and utilization system for a hoisting machine according to claim 1, characterized in that: The fixed-displacement motor in the recovery circuit is interconnected with the solenoid directional control valve in the main circuit through a pipeline.

4. An environmental protection and energy-saving hoisting machinery multi-condition potential energy recovery and utilization system according to claim 1, characterized in that: On the pipeline between the check valve Ⅰ and the fixed-displacement pump in the main circuit, another pipeline is connected to the energy release control valve Ⅰ in the recovery circuit through a check valve Ⅵ, and then connected to the energy release control valve Ⅱ in the recovery circuit through a check valve Ⅶ.

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