阅读说明：本技术 一种组合式液压势能再生系统 (Combined hydraulic potential energy regeneration system ) 是由 贺湘宇 谭丽莎 肖广鑫 袁玉林 蒋梦军 于 2020-07-06 设计创作，主要内容包括：本发明公开一种组合式液压势能再生系统,包括油箱、工作单元、增压单元、储能单元、控制单元以及动力单元；其中,所述工作单元包括主液压缸、负载、第一辅助液压缸、第二辅助液压缸；所述压力单元包括单作用增压缸缸体、活塞、活塞杆等；所述储能单元有蓄能器；所述控制单元包括单向阀、三位四通电磁换向阀、两位两通电磁换向阀；所述动力单元包括液压泵和电动机。本发明能够在负载下降时,将负载产生的重力势能转化为液压油的压力能,经过管道的运输,流经一个单作用增压缸,根据增压缸的工作原理,可将输入压力进行变换,以较高压力输出并储存到蓄能器中,在负载上升时,推动第一辅助液压缸和第二辅助液压缸的活塞杆由无杆腔向有杆腔移动,共同辅助主液压缸推动负载上升,从而提高回路能量回收利用率,更好的实现液压能量再生,达到节约能源的效果。(The invention discloses a combined hydraulic potential energy regeneration system which comprises an oil tank, a working unit, a pressurization unit, an energy storage unit, a control unit and a power unit, wherein the working unit is connected with the oil tank; the working unit comprises a main hydraulic cylinder, a load, a first auxiliary hydraulic cylinder and a second auxiliary hydraulic cylinder; the pressure unit comprises a single-action pressure cylinder body, a piston rod and the like; the energy storage unit is provided with an energy accumulator; the control unit comprises a one-way valve, a three-position four-way electromagnetic reversing valve and a two-position two-way electromagnetic reversing valve; the power unit includes a hydraulic pump and an electric motor. The invention can convert the gravitational potential energy generated by the load into the pressure energy of the hydraulic oil when the load descends, the pressure energy flows through a single-action pressure cylinder after being transported by a pipeline, the input pressure can be converted according to the working principle of the pressure cylinder, the input pressure is output at higher pressure and stored in the energy accumulator, when the load ascends, the piston rods of the first auxiliary hydraulic cylinder and the second auxiliary hydraulic cylinder are pushed to move from the rodless cavity to the rod cavity, and the main hydraulic cylinder is jointly assisted to push the load to ascend, thereby improving the energy recovery utilization rate of a loop, better realizing the regeneration of hydraulic energy and achieving the effect of saving energy.)

1. The invention discloses a combined hydraulic potential energy regeneration system, which comprises an oil tank, a working unit (10), a pressurization unit (20), an energy storage unit (30), a control unit (40) and a power unit (50);

the working unit (10) comprises a first auxiliary hydraulic cylinder (11), a main hydraulic cylinder (12), a load (13) and a second auxiliary hydraulic cylinder (14);

the pressurization unit (20) comprises a single-action pressurization cylinder body (21), a first piston (22), a piston rod (23) and a second piston (24), wherein the first piston (22) and the second piston (24) are fastened at two ends of the piston rod (23) and can freely slide in the single-action pressurization cylinder body (21);

the energy storage unit (30) comprises an accumulator (31);

the power unit (50) comprises a hydraulic pump (51) and an electric motor (52);

the method is characterized in that:

the control unit (40) comprises a one-way valve (41), a first two-position two-way electromagnetic directional valve (42), a three-position four-way electromagnetic directional valve (43), a second two-position two-way electromagnetic directional valve (44), a third two-position two-way electromagnetic directional valve (45), a fourth two-position two-way electromagnetic directional valve (46) and a fifth two-position two-way electromagnetic valve (47);

the pressurizing unit (20) also comprises a pressurizing cylinder resetting loop which consists of an auxiliary hydraulic pump (25), a hydraulic control one-way valve (26) and a one-way valve (27) and is used for resetting the pressurizing cylinder after the hydraulic potential energy is recovered; the auxiliary hydraulic pump (25) is respectively connected with a control port P of the hydraulic control one-way valve (26) and an inlet of the one-way valve (27), an outlet of the hydraulic control one-way valve (26) and an outlet of the one-way valve (27) are respectively connected with a port C and a port D of the cylinder body (21) of the pressure cylinder, and an inlet of the hydraulic control one-way valve (26) is connected with an oil tank;

the load (13) is respectively connected with piston rods of a first auxiliary hydraulic cylinder (11), a main hydraulic cylinder (12), a second auxiliary hydraulic cylinder (14) and the like, and oil ports of rod cavities of the first auxiliary hydraulic cylinder (11) and the second auxiliary hydraulic cylinder (14) are connected with an oil tank; the rodless cavity oil ports of the first auxiliary hydraulic cylinder (11) and the second auxiliary hydraulic cylinder (14) are connected and then combined into an oil path, the oil path is respectively connected with a port B of a fourth two-position two-way electromagnetic directional valve (46) and a port A of a fifth two-position two-way electromagnetic valve (47), the port A of the fourth two-position two-way electromagnetic directional valve (46) is connected with an energy accumulator (31), and the port B of the fifth two-position two-way electromagnetic valve (47) is connected with an oil tank;

an oil port of a rod cavity of the main hydraulic cylinder (12) is connected with a port B of the three-position four-way electromagnetic directional valve (43); an oil port of a rodless cavity of the main hydraulic cylinder (12) is respectively connected with two oil ways, the first oil way is connected with an A port of a three-position four-way electromagnetic directional valve (43), and the second oil way is connected with a B port of a second two-position two-way electromagnetic valve (44); an A port of the second two-position two-way electromagnetic valve (44) is connected with an A port of the single-action pressurizing cylinder body (21), a B port of the single-action pressurizing cylinder body (21) is connected with a B port of a third two-position two-way electromagnetic reversing valve (45), and the A port of the third two-position two-way electromagnetic reversing valve (45) is connected with the energy accumulator (31);

the port C of the three-position four-way electromagnetic directional valve (43) is connected with an oil outlet of a hydraulic pump (51), an oil inlet of the hydraulic pump (51) is connected with an oil outlet of the one-way valve (41), and an oil inlet of the one-way valve (41) is connected to an oil tank; and a D port of the three-position four-way electromagnetic directional valve (43) is connected with an A port of the first two-position two-way electromagnetic directional valve (42), and a B port of the first two-position two-way electromagnetic directional valve (42) is connected with an oil tank.

2. The combined hydraulic potential energy regeneration system of claim 1, wherein: the working strokes of a main hydraulic cylinder (12), a first auxiliary hydraulic cylinder (11) and a second auxiliary hydraulic cylinder (14) in the working unit (10) are equal.

3. The combined hydraulic potential energy regeneration system of claim 1, wherein: a master hydraulic cylinder (12) in the working unit (10) is A1, a first auxiliary hydraulic cylinder (11) is A2, a second auxiliary hydraulic cylinder (14) is A3, the area of a first piston (22) in the pressure increasing unit (20) is B1, the area of a second piston (24) in the pressure increasing unit is B2, A2= A3, A1= A2B 1/B2/2.

4. The combined hydraulic potential energy regeneration system of claim 1, wherein: the 'normal position' of the first two-position two-way electromagnetic directional valve (42), the second two-position two-way electromagnetic valve (44), the third two-position two-way electromagnetic directional valve (45), the fourth two-position two-way electromagnetic directional valve (46) and the fifth two-position two-way electromagnetic directional valve (47) is a position far away from the electromagnetic valves, the 'control position' is a position close to the electromagnetic valves, the middle position of the three-position four-way electromagnetic directional valve (43) is the 'normal position', the left position and the right position are the 'control positions', the 'normal position' refers to the position where the reversing valve is located in a power-off state, and the 'control position' refers to the position where the reversing valve is located in a power-on state.

5. The invention discloses a combined hydraulic potential energy regeneration system, which comprises an oil tank, a working unit (110), a pressurization unit (120), an energy storage unit (130), a control unit (140) and a power unit (150);

the working unit (110) comprises a first inverted auxiliary hydraulic cylinder (111), a main hydraulic cylinder (112), a load (113), a second inverted auxiliary hydraulic cylinder (114) and a connecting rod (115);

the pressurization unit (120) comprises a single-action pressurization cylinder body (121), a first piston (122), a piston rod (123) and a second piston (124), wherein the first piston (122) and the second piston (124) are fastened at two ends of the piston rod (123) and can freely slide in the single-action pressurization cylinder body (121);

the energy storage unit (130) comprises an accumulator (131);

the power unit (150) comprises a hydraulic pump (151), an electric motor (152);

the method is characterized in that:

the control unit (140) comprises a one-way valve (141), a first two-position two-way electromagnetic directional valve (142), a three-position four-way electromagnetic directional valve (143), a second two-position two-way electromagnetic directional valve (144), a third two-position two-way electromagnetic directional valve (145), a fourth two-position two-way electromagnetic directional valve (146) and a fifth two-position two-way electromagnetic valve (47);

the pressurizing unit (120) further comprises a pressurizing cylinder resetting loop consisting of an auxiliary hydraulic pump (125), a hydraulic control one-way valve (126) and a one-way valve (127), and the pressurizing cylinder resetting loop is used for resetting the pressurizing cylinder after hydraulic potential energy recovery is finished; the auxiliary hydraulic pump (125) is respectively connected with a control port P of the hydraulic control one-way valve (126) and an inlet of the one-way valve (127), an outlet of the hydraulic control one-way valve (126) and an outlet of the one-way valve (127) are respectively connected with a port C and a port D of the cylinder body (121) of the pressure cylinder, and an inlet of the hydraulic control one-way valve (126) is connected with an oil tank;

the load (113) is connected to a piston rod of the master cylinder (112) and the bottoms of the first inverted auxiliary hydraulic cylinder (111) and the second inverted auxiliary hydraulic cylinder (114), respectively; the connecting rod (115) is respectively connected with the piston rods of the first inverted auxiliary hydraulic cylinder (111) and the second inverted auxiliary hydraulic cylinder (114) and the bottom of the main hydraulic cylinder (112); oil ports of rod cavities of the first inverted auxiliary hydraulic cylinder (111) and the second inverted auxiliary hydraulic cylinder (114) are connected with an oil tank; the rodless cavity oil ports of the first inverted auxiliary hydraulic cylinder (111) and the second inverted auxiliary hydraulic cylinder (114) are connected and then combined into an oil path, the oil path is respectively connected with a port B of a fourth two-position two-way electromagnetic directional valve (146) and a port A of a fifth two-position two-way electromagnetic valve (147), wherein the port A of the fourth two-position two-way electromagnetic directional valve (146) is connected with an energy accumulator (131), and the port B of the fifth two-position two-way electromagnetic valve (147) is connected with an oil tank;

an oil port of a rod cavity of the master hydraulic cylinder (112) is connected with a port B of the three-position four-way electromagnetic directional valve (143); an oil port of a rodless cavity of the main hydraulic cylinder (112) is respectively connected with two oil ways, the first oil way is connected with an A port of the three-position four-way electromagnetic directional valve (143), and the second oil way is connected with a B port of the second two-position two-way electromagnetic valve (144); an A port of the second two-position two-way electromagnetic valve (144) is connected with an A port of the single-action pressure cylinder body (121), a B port of the single-action pressure cylinder body (121) is connected with a B port of the third two-position two-way electromagnetic directional valve (145), and the A port of the third two-position two-way electromagnetic directional valve (145) is connected with the energy accumulator (131);

the port C of the three-position four-way electromagnetic reversing valve (143) is connected with an oil outlet of a hydraulic pump (151), an oil inlet of the hydraulic pump (151) is connected with an oil outlet of a one-way valve (141), and an oil inlet of the one-way valve (141) is connected to an oil tank; and a port D of the three-position four-way electromagnetic directional valve (143) is connected with a port A of the first two-position two-way electromagnetic directional valve (142), and a port B of the first two-position two-way electromagnetic directional valve (142) is connected with an oil tank.

Technical Field

The invention relates to a combined hydraulic potential energy regeneration system.

Background

The hydraulic technology is one of the key technologies for realizing modern transmission and control, and countries in the world pay great attention to the development of the hydraulic industry. At present, the hydraulic technology can realize stepless speed regulation, has large power-weight ratio and small volume, can realize quick start, braking and frequent reversing, is widely applied to various large engineering fields, and is expected to be applied to wider fields in the future. However, the hydraulic technology has the disadvantage of low transmission efficiency, so that energy conservation of the hydraulic cylinder has attracted extensive attention and attention.

The invention converts the gravitational potential energy generated when the load is reduced into the pressure energy of the hydraulic oil, the hydraulic oil flows through a single-action pressure cylinder after being transported by a pipeline, the input pressure can be converted according to the working principle of the pressure cylinder, and the input pressure is output and stored into an energy accumulator at higher pressure, thereby improving the energy recovery utilization rate of a loop, better realizing the regeneration of hydraulic energy and achieving the effect of saving energy

Accordingly, the present inventors have made extensive studies to solve the above problems and have made the present invention.

Disclosure of Invention

The invention discloses a combined hydraulic potential energy regeneration system, which comprises an oil tank, a working unit, a pressurization unit, an energy storage unit, a control unit and a power unit, wherein the working unit is connected with the oil tank;

the working unit comprises a first auxiliary hydraulic cylinder, a main hydraulic cylinder, a load and a second auxiliary hydraulic cylinder;

the pressurizing unit comprises a single-action pressurizing cylinder body, a first piston, a piston rod and a second piston, wherein the first piston and the second piston are fastened at two ends of the piston rod and can freely slide in the single-action pressurizing cylinder body;

the energy storage unit comprises an energy accumulator;

the power unit comprises a hydraulic pump and a motor;

the method is characterized in that:

the control unit comprises a one-way valve, a first two-position two-way electromagnetic reversing valve, a three-position four-way electromagnetic reversing valve, a second two-position two-way electromagnetic reversing valve, a third two-position two-way electromagnetic reversing valve, a fourth two-position two-way electromagnetic reversing valve and a fifth two-position two-way electromagnetic valve;

the pressurizing unit also comprises a pressurizing cylinder resetting loop consisting of an auxiliary hydraulic pump, a hydraulic control one-way valve and a one-way valve, and the pressurizing cylinder resetting loop is used for resetting the pressurizing cylinder after hydraulic potential energy recovery is finished; the auxiliary hydraulic pump is respectively connected with a control port P of the hydraulic control one-way valve and an inlet of the one-way valve, an outlet of the hydraulic control one-way valve and an outlet of the one-way valve are respectively connected with a port C and a port D of the cylinder body of the pressure cylinder, and an inlet of the hydraulic control one-way valve is connected with the oil tank;

the load is respectively connected with piston rods of the first auxiliary hydraulic cylinder, the main hydraulic cylinder, the second auxiliary hydraulic cylinder and the like, and oil ports of rod cavities of the first auxiliary hydraulic cylinder and the second auxiliary hydraulic cylinder are connected with an oil tank; the rodless cavity oil ports of the first auxiliary hydraulic cylinder and the second auxiliary hydraulic cylinder are connected and then combined into an oil path, the oil path is respectively connected with a port B of a fourth two-position two-way electromagnetic directional valve and a port A of a fifth two-position two-way electromagnetic valve, the port A of the fourth two-position two-way electromagnetic directional valve is connected with an energy accumulator, and the port B of the fifth two-position two-way electromagnetic valve is connected with an oil tank;

an oil port of a rod cavity of the main hydraulic cylinder is connected with a port B of the three-position four-way electromagnetic directional valve; the oil port of the rodless cavity of the main hydraulic cylinder is respectively connected with two oil ways, the first oil way is connected with the port A of the three-position four-way electromagnetic directional valve, and the second oil way is connected with the port B of the second two-position two-way electromagnetic valve; the port A of the second two-position two-way electromagnetic valve is connected with the port A of the single-action pressure cylinder body, the port B of the single-action pressure cylinder body is connected with the port B of the third two-position two-way electromagnetic directional valve, and the port A of the third two-position two-way electromagnetic directional valve is connected with the energy accumulator;

the port C of the three-position four-way electromagnetic directional valve is connected with an oil outlet of a hydraulic pump, an oil inlet of the hydraulic pump is connected with an oil outlet of a one-way valve, and an oil inlet of the one-way valve is connected to an oil tank; and a port D of the three-position four-way electromagnetic directional valve is connected with a port A of the first two-position two-way electromagnetic directional valve, and a port B of the first two-position two-way electromagnetic directional valve is connected with an oil tank.

Preferably, the working strokes of the main hydraulic cylinder, the first auxiliary hydraulic cylinder and the second auxiliary hydraulic cylinder in the working unit are equal.

Preferably, the master cylinder in the working unit is a1, the first auxiliary hydraulic cylinder is a2, and the second auxiliary hydraulic cylinder is A3, the area of the first piston in the pressure unit is B1, and the area of the second piston in the pressure unit is B2, wherein a2= A3, and a1= a2= B1/B2/2.

Preferably, the "normal position" of the first two-position two-way electromagnetic directional valve, the second two-position two-way electromagnetic valve, the third two-position two-way electromagnetic directional valve, the fourth two-position two-way electromagnetic directional valve and the fifth two-position two-way electromagnetic directional valve is a position far away from the electromagnetic valve, the "control position" is a position close to the electromagnetic valve, the middle position of the three-position four-way electromagnetic directional valve is the "normal position", the left position and the right position are the "control position", wherein the "normal position" refers to a position where the directional valve is located in a power-off state, and the "control position" refers to a position where the directional valve is located in a power-on state.

The invention discloses a combined hydraulic potential energy regeneration system, which comprises an oil tank, a working unit, a pressurization unit, an energy storage unit, a control unit and a power unit, wherein the working unit is connected with the oil tank;

the working unit comprises a first inverted auxiliary hydraulic cylinder, a main hydraulic cylinder, a load, a second inverted auxiliary hydraulic cylinder and a connecting rod;

the pressurizing unit comprises a single-action pressurizing cylinder body, a first piston, a piston rod and a second piston, wherein the first piston and the second piston are fastened at two ends of the piston rod and can freely slide in the single-action pressurizing cylinder body;

the energy storage unit comprises an energy accumulator;

the power unit comprises a hydraulic pump and a motor;

the method is characterized in that:

the control unit comprises a one-way valve, a first two-position two-way electromagnetic reversing valve, a three-position four-way electromagnetic reversing valve, a second two-position two-way electromagnetic reversing valve, a third two-position two-way electromagnetic reversing valve, a fourth two-position two-way electromagnetic reversing valve and a fifth two-position two-way electromagnetic valve;

the pressurizing unit also comprises a pressurizing cylinder resetting loop consisting of an auxiliary hydraulic pump, a hydraulic control one-way valve and a one-way valve, and the pressurizing cylinder resetting loop is used for resetting the pressurizing cylinder after hydraulic potential energy recovery is finished; the auxiliary hydraulic pump is respectively connected with a control port P of the hydraulic control one-way valve and an inlet of the one-way valve, an outlet of the hydraulic control one-way valve and an outlet of the one-way valve are respectively connected with a port C and a port D of the cylinder body of the pressure cylinder, and an inlet of the hydraulic control one-way valve is connected with the oil tank;

the load is respectively connected with a piston rod of the main hydraulic cylinder and the bottoms of the first inverted auxiliary hydraulic cylinder and the second inverted auxiliary hydraulic cylinder; the connecting rod is respectively connected with piston rods of the first inverted auxiliary hydraulic cylinder and the second inverted auxiliary hydraulic cylinder and the bottom of the main hydraulic cylinder; oil ports of rod cavities of the first inverted auxiliary hydraulic cylinder and the second inverted auxiliary hydraulic cylinder are connected with an oil tank; the rodless cavity oil ports of the first auxiliary hydraulic cylinder and the second auxiliary hydraulic cylinder are connected and then combined into an oil path, and the oil path is respectively connected with a port B of a fourth two-position two-way electromagnetic directional valve and a port A of a fifth two-position two-way electromagnetic valve, wherein the port A of the fourth two-position two-way electromagnetic directional valve is connected with an energy accumulator, and the port B of the fifth two-position two-way electromagnetic valve is connected with an oil tank;

an oil port of a rod cavity of the main hydraulic cylinder is connected with a port B of the three-position four-way electromagnetic directional valve; the oil port of the rodless cavity of the main hydraulic cylinder is respectively connected with two oil ways, the first oil way is connected with the port A of the three-position four-way electromagnetic directional valve, and the second oil way is connected with the port B of the second two-position two-way electromagnetic valve; the port A of the second two-position two-way electromagnetic valve is connected with the port A of the single-action pressure cylinder body, the port B of the single-action pressure cylinder body is connected with the port B of the third two-position two-way electromagnetic directional valve, and the port A of the third two-position two-way electromagnetic directional valve is connected with the energy accumulator;

the port C of the three-position four-way electromagnetic directional valve is connected with an oil outlet of a hydraulic pump, an oil inlet of the hydraulic pump is connected with an oil outlet of a one-way valve, and an oil inlet of the one-way valve is connected to an oil tank; and a port D of the three-position four-way electromagnetic directional valve is connected with a port A of the first two-position two-way electromagnetic directional valve, and a port B of the first two-position two-way electromagnetic directional valve is connected with an oil tank.

Other aspects, objects, and advantages of the invention will become apparent from the following description taken in conjunction with the accompanying drawings.

Drawings

The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic diagram of the present invention in its normal position;

FIG. 2 is a schematic diagram of the load shedding process of the present invention;

FIG. 3 is a schematic diagram of the load lifting process of the present invention;

fig. 4 is a normal position principle diagram of the hydraulic potential energy regeneration system of the invention (inverted cylinder).

The reference numbers are as follows:

10-a working unit; 11-a first auxiliary hydraulic cylinder; 12-master cylinder; 13-load; 14-a second helper hydraulic cylinder; 20-a pressurizing unit; 21-single-acting pressure cylinder body; 22-a first piston; 23-a piston rod; 24-a second piston; 25-an auxiliary hydraulic pump; 26-a pilot operated check valve; 27-a one-way valve; 30-an energy storage unit; 31-an accumulator; 40-a control unit; 41-one-way valve; 42-a first two-position two-way electromagnetic directional valve; 43-three-position four-way electromagnetic directional valve; 44-a second two-position two-way electromagnetic directional valve; 45-a third two-position two-way electromagnetic directional valve; 46-a fourth two-position two-way electromagnetic directional valve; 47-a fifth two-position two-way electromagnetic directional valve; 50-a power unit; 51-a hydraulic pump; 52-electric motor.

Detailed Description

In order to further explain the technical scheme of the invention, the following detailed description is combined with the accompanying drawings.

As shown in fig. 1, a combined hydraulic potential energy regeneration system includes an oil tank, a working unit 10, a pressurizing unit 20, an energy storage unit 30, a control unit 40, and a power unit 50;

the working unit 10 comprises a first auxiliary hydraulic cylinder 11, a main hydraulic cylinder 12, a load 13 and a second auxiliary hydraulic cylinder 14;

the pressurizing unit 20 comprises a single-acting pressurizing cylinder body 21, a first piston 22, a piston rod 23 and a second piston 24, wherein the first piston 22 and the second piston 24 are both fastened at two ends of the piston rod 23 and can freely slide in the single-acting pressurizing cylinder body 21;

the energy storage unit 30 comprises an accumulator 31;

the power unit 50 includes a hydraulic pump 51, an electric motor 52;

the method is characterized in that:

the control unit 40 comprises a one-way valve 41, a first two-position two-way electromagnetic directional valve 42, a three-position four-way electromagnetic directional valve 43, a second two-position two-way electromagnetic directional valve 44, a third two-position two-way electromagnetic directional valve 45, a fourth two-position two-way electromagnetic directional valve 46 and a fifth two-position two-way electromagnetic valve 47;

the pressurizing unit 20 further comprises a pressurizing cylinder resetting loop which is composed of an auxiliary hydraulic pump 25, a hydraulic control one-way valve 26 and a one-way valve 27 and is used for resetting the pressurizing cylinder after hydraulic potential energy recovery is finished; the auxiliary hydraulic pump 25 is respectively connected with a control port P of a hydraulic control one-way valve 26 and an inlet of a one-way valve 27, an outlet of the hydraulic control one-way valve 26 and an outlet of the one-way valve 27 are respectively connected with a port C and a port D of the cylinder body 21 of the pressure cylinder, and an inlet of the hydraulic control one-way valve 26 is connected with an oil tank;

the load 13 is respectively connected with piston rods of the first auxiliary hydraulic cylinder 11, the main hydraulic cylinder 12, the second auxiliary hydraulic cylinder 14 and the like, and oil ports of rod cavities of the first auxiliary hydraulic cylinder 11 and the second auxiliary hydraulic cylinder 14 are connected with an oil tank; the rodless cavity oil ports of the first auxiliary hydraulic cylinder 11 and the second auxiliary hydraulic cylinder 14 are connected and then combined into an oil path, the oil path is respectively connected with the port B of the fourth two-position two-way electromagnetic directional valve 46 and the port A of the fifth two-position two-way electromagnetic valve 47, the port A of the fourth two-position two-way electromagnetic directional valve 46 is connected with the energy accumulator 31, and the port B of the fifth two-position two-way electromagnetic valve 47 is connected with the oil tank;

an oil port of a rod cavity of the main hydraulic cylinder 12 is connected with a port B of the three-position four-way electromagnetic directional valve 43; the oil port of the rodless cavity of the master hydraulic cylinder 12 is respectively connected with two oil paths, the first is connected with the port A of the three-position four-way electromagnetic directional valve 43, and the second is connected with the port B of the second two-position two-way electromagnetic valve 44; the port A of the second two-position two-way electromagnetic valve 44 is connected with the port A of the single-action pressure cylinder body 21, the port B of the single-action pressure cylinder body 21 is connected with the port B of the third two-position two-way electromagnetic directional valve 45, and the port A of the third two-position two-way electromagnetic directional valve 45 is connected with the energy accumulator 31;

the port C of the three-position four-way electromagnetic directional valve 43 is connected with an oil outlet of a hydraulic pump 51, an oil inlet of the hydraulic pump 51 is connected with an oil outlet of a one-way valve 41, and an oil inlet of the one-way valve 41 is connected to an oil tank; the port D of the three-position four-way electromagnetic directional valve 43 is connected with the port A of the first two-position two-way electromagnetic directional valve 42, and the port B of the first two-position two-way electromagnetic directional valve 42 is connected with the oil tank.

The working strokes of the master cylinder 12, the first auxiliary cylinder 11, and the second auxiliary cylinder 14 in the working unit 10 are equal.

The main hydraulic cylinder 12 in the working unit 10 is a1, the first auxiliary hydraulic cylinder 11 is a2, the second auxiliary hydraulic cylinder 14 is A3, the area of the first piston 22 in the pressure unit 20 is B1, and the area of the second piston 24 in the pressure unit 20 is B2, wherein a2= A3, and a1= a2 × B1/B2/2.

The "normal position" of the first two-position two-way electromagnetic directional valve 42, the second two-position two-way electromagnetic valve 44, the third two-position two-way electromagnetic directional valve 45, the fourth two-position two-way electromagnetic directional valve 46 and the fifth two-position two-way electromagnetic directional valve 47 is a position far away from the electromagnetic valves, the "control position" is a position close to the electromagnetic valves, the middle position of the three-position four-way electromagnetic directional valve 43 is the "normal position", the left position and the right position are the "control positions", wherein the "normal position" refers to a position where the directional valve is located in a power-off state, and the "control position" refers to a position where the directional valve is located in a power-on state.

As shown in fig. 2, the working principle of the descending process of the load 13 of the present invention is described as follows:

energy recovery: when the motor 52 is started, the first two-position two-way electromagnetic directional valve 42, the three-position four-way electromagnetic directional valve 43, the second two-position two-way electromagnetic valve 44, the third two-position two-way electromagnetic directional valve 45 and the fifth two-position two-way electromagnetic directional valve 47 are powered on and are all in a "control position", the fourth two-position two-way electromagnetic directional valve 46 is powered off and is in a "normal position"; the check valve 41 is opened. The hydraulic oil in the oil tank flows through the control position, namely the left position C-B, of the three-position four-way electromagnetic directional valve 43 through the check valve 41, then flows into the rod cavity oil port of the master hydraulic cylinder 12 along the pipeline, the hydraulic pressure force pushes the piston rod of the master hydraulic cylinder 12 to move towards the rodless cavity of the master hydraulic cylinder 12, and therefore the hydraulic oil in the rodless cavity is pushed to flow out from the rodless cavity oil port, and the load 13 begins to descend. The hydraulic oil flowing out from the rodless cavity oil port of the master cylinder 12 flows to the right B-A of the second two-position two-way electromagnetic valve 44 through a pipeline and then flows into the A port of the single-action pressure cylinder body 21, after the hydraulic oil enters the large cavity of the single-action pressure cylinder body 21, the second piston 24 is pushed to move towards the small cavity of the single-action pressure cylinder body 21, the hydraulic oil in the small cavity is extruded from the B port of the single-action pressure cylinder body 21 to be high-pressure oil, and the high-pressure oil flows through the right B-A of the third two-position two-way electromagnetic reversing valve 45 and enters the energy accumulator 31, and the gravitational potential energy of the descending load 13 is stored in the energy accumulator 31.

As shown in fig. 3, the working principle of the load 13 ascending process of the present invention is described as follows:

energy release: the three-position four-way electromagnetic directional valve 43 and the fourth two-position two-way electromagnetic directional valve 46 are powered on and are both in the "control position", and the first two-position two-way electromagnetic directional valve 42, the second two-position two-way electromagnetic valve 44, the third two-position two-way electromagnetic directional valve 45 and the fifth two-position two-way electromagnetic directional valve 47 are powered off and are both in the "normal position". Hydraulic oil in the oil tank flows through a control position, namely a right position C-A, of the three-position four-way electromagnetic directional valve 43 through the check valve 41, then flows into a rodless cavity oil port of the main hydraulic cylinder 12 along a pipeline, the hydraulic pressure force pushes a piston rod of the main hydraulic cylinder 12 to move towards a rod cavity of the main hydraulic cylinder 12, accordingly, hydraulic cylinder oil in the rod cavity is pushed to flow out from the oil port of the rod cavity, and the load 13 starts to rise. The pressure oil flowing out from the oil port of the rod cavity of the master cylinder 12 flows through a pipeline to the control position, namely the right position B-D, of the three-position four-way electromagnetic directional valve 43, then flows into the left position A-B of the first two-position two-way electromagnetic directional valve 42, and finally flows back to the oil tank. When a piston rod of the master hydraulic cylinder 12 moves from a rodless cavity to a rod cavity, high-pressure oil pressure energy stored in the energy accumulator 31 in the energy recovery process can assist in driving the rotation of the rotary pump, the input of power of a rotary motor is reduced, the high-pressure oil pressure energy stored in the energy accumulator 31 can flow through the right A-B position of the fourth two-position two-way electromagnetic directional valve 46 and then is divided into two oil ways, one oil way flows into the rodless cavity of the first auxiliary hydraulic cylinder 11, the other oil way flows into the rodless cavity of the second auxiliary hydraulic cylinder 14, and the master hydraulic cylinder 12 is assisted together to push the load 13 to ascend, so that the energy recovery utilization rate of a loop is improved, the hydraulic energy regeneration is better realized, and the effect of saving energy is achieved.

Single-acting pressure cylinder return circuit: after the hydraulic oil in the oil tank flows through the auxiliary hydraulic pump 25, the hydraulic oil works along the two oil paths respectively. The first oil flows through the check valve 27 and then flows into the oil port D of the small cavity of the cylinder body 21 of the single-action pressure cylinder, the oil pressure pushes the first piston 22 to move towards the large cavity of the cylinder body 21 of the single-action pressure cylinder, and oil in the large cavity flows out from the port C of the large cavity under pressure; the pressure oil from the auxiliary hydraulic pump 25 flows through the pilot port P of the pilot operated check valve 26, which is the second oil path, and the pilot pressure is inputted to the pilot port P, and the pilot operated check valve 26 is reversely circulated, so that the pressure oil from the large chamber C of the single-acting cylinder block 22 can flow through the pilot operated check valve 26 and finally flow back to the oil tank.