阅读说明：本技术 一种能量回收控制系统及吊装设备 (Energy recovery control system and hoisting equipment ) 是由 任军辉 郭大千 袁光金 于 2020-11-23 设计创作，主要内容包括：本发明公开了一种能量回收控制系统及吊装设备,控制系统包括油泵、油箱、主控制阀、能量回收装置和俯仰阀组；能量回收装置包括第一、第二油路、设于第一油路上的控制阀一和马达,与马达传动连接的发电装置、与发电装置电连接的蓄电装置,及设于第二油路上的控制阀二；俯仰阀组包括单向阀二、控制阀三、单向阀三、控制阀四和逻辑阀。单向阀二设于A6口与B3口之间；单向阀三设于B3口与B2口之间,控制阀三设于单向阀二与单向阀三的进油口之间,逻辑阀设于A5口与A6口之间。该系统可根据选择对吊装设备吊臂下降(俯)工作时产生的势能进行回收利用,且还可便捷地实现对俯仰油缸伸出后的位置锁定,以及根据需要实现俯仰油缸快速伸出。(The invention discloses an energy recovery control system and hoisting equipment, wherein the control system comprises an oil pump, an oil tank, a main control valve, an energy recovery device and a pitching valve group; the energy recovery device comprises a first oil way, a second oil way, a first control valve and a motor which are arranged on the first oil way, a power generation device in transmission connection with the motor, an electric storage device electrically connected with the power generation device, and a second control valve arranged on the second oil way; the pitching valve group comprises a one-way valve II, a control valve III, a one-way valve III, a control valve IV and a logic valve. The check valve II is arranged between the port A6 and the port B3; the check valve III is arranged between the port B3 and the port B2, the control valve III is arranged between the check valve II and the oil inlet of the check valve III, and the logic valve is arranged between the port A5 and the port A6. The system can recycle potential energy generated when the suspension arm of the hoisting equipment descends (bends) according to selection, can conveniently lock the position of the extended pitching oil cylinder, and can rapidly extend the pitching oil cylinder according to requirements.)

1. An energy recovery control system comprises a hydraulic oil pump (5), a hydraulic oil tank (6) and a main control valve (4) for controlling the extension and retraction of a pitching oil cylinder (1), wherein the main control valve (4) is provided with an oil inlet A1, an oil return port T, a working oil port A2 and a working oil port B1, the oil inlet A1 is communicated with an oil outlet of the hydraulic oil pump (5), the oil return port T is communicated with the hydraulic oil tank (6), and an oil inlet of the hydraulic oil pump (5) is communicated with the hydraulic oil tank (6); the device is characterized by also comprising an energy recovery device (3) and a pitching valve bank (2);

the energy recovery device (3) is provided with an A4 port communicated with an A5 port of the pitching valve group (2) and an A3 port communicated with a working oil port A2 of the main control valve (4);

the energy recovery device (3) comprises a first oil path and a second oil path which are arranged between an A4 port and an A3 port, a first control valve (31) and a motor (34) which are arranged on the first oil path, a power generation device (32) in transmission connection with the motor (34), a power storage device (33) electrically connected with the power generation device (32), and a second control valve (36) which is arranged on the second oil path, wherein the first control valve (31) is arranged between the A4 port and an A7 port of the motor (34); the second control valve (36) is arranged between the A8 port and the A4 port of the motor (34);

when the first control valve (31) and the second control valve (36) are electrified, the first control valve (31) is communicated with the first oil way, and the second control valve (36) closes the second oil way; when the first control valve (31) and the second control valve (36) are powered off, the first control valve (31) closes the first oil way, and the second control valve (36) is communicated with the second oil way;

the pitching valve group (2) is provided with an A5 port communicated with an A4 port of the energy recovery device (3), an A6 port communicated with a rodless cavity of the pitching cylinder (1), a B3 port communicated with a rod cavity of the pitching cylinder (1), a B2 port communicated with a B1 port of the main control valve (4), and a drain port T2 communicated with the hydraulic oil tank (6);

the pitching valve group (2) comprises a second one-way valve (22); a third control valve (21); a third check valve (26); a control valve four (27) and a logic valve (25);

the check valve II (22) is arranged between the port A6 and the port B3, and the check valve II (22) is used for preventing the hydraulic oil from flowing from the port A6 to the port B3;

the check valve III (26) is arranged between the port B3 and the port B2, and the check valve III (26) is used for preventing the hydraulic oil from flowing from the port B3 to the port B2;

the third control valve (21) is arranged between the oil inlet of the second check valve (22) and the oil inlet of the third check valve (26), and in a power-off state, hydraulic oil can flow to the oil inlet end of the second check valve (22) and the port B3 through the third check valve (26) and the third control valve (21) simultaneously;

the logic valve (25) is arranged between the port A5 and the port A6, the logic valve (25) is provided with a first working port (251), a second working port (252) and a control port (253), the first working port (251) is communicated with the port A6, the second working port (252) is connected with the port A5, and the control port (253) is communicated with an oil inlet of a control valve IV (27);

the oil outlet of the control valve IV (27) is communicated with the port T2, and in a power-off state, hydraulic oil cannot flow from the control port (253) of the logic valve (25) to the port T2 through the control valve IV (27).

2. The energy recovery control system of claim 1 wherein a first check valve (35) is disposed on the first oil path, the first check valve (35) being disposed between the port A8 of the motor (34) and the port A3 of the control valve two (36), the first check valve (35) being configured to prevent hydraulic oil from flowing from the port A3 and the port two (36) to the motor (34).

3. The energy recovery control system according to claim 1, wherein the first control valve (31) is a two-position two-way solenoid valve which is closed when power is off and is communicated when power is on, and hydraulic oil can flow in two directions or in one direction.

4. The energy recovery control system of claim 1, wherein the second control valve (36) is a two-position two-way solenoid valve that is in a communication state when de-energized and in a closed state when energized, and allows bi-directional flow of hydraulic oil.

5. The energy recovery control system according to any of claims 1-4, wherein the pitch valve group (2) further comprises a throttle device (24) and an overpressure protection valve (23), the throttle device (24) comprising a first throttle valve (241) and a second throttle valve (242);

the overpressure protection valve (23) is arranged between a first working port (251) of the logic valve (25) and an oil outlet of the control valve IV (27), and an overflow oil port of the overpressure protection valve (23) is communicated with a port T2;

the first throttle valve (241) is arranged between a control port (253) of the logic valve (25) and an oil inlet of a control valve IV (27), one oil port of the second throttle valve (242) is communicated with the oil inlet of the overpressure protection valve (23), and the other oil port of the second throttle valve (242) is communicated with both the oil outlet of the first throttle valve (241) and the oil inlet of the control valve IV (27).

6. The energy recovery control system according to any one of claims 1 to 4, wherein the third control valve (21) is a two-position two-way solenoid valve which is in a two-way communication state when de-energized and in a one-way communication state when energized.

7. The energy recovery control system according to any one of claims 1 to 4, wherein the control valve four (27) is a two-position two-way solenoid valve which is closed when de-energized and open when energized, and in which hydraulic oil can flow only in one direction.

8. The energy recovery control system according to claim 5, characterized in that the pitch cylinders (1) are provided with two sets, the pitch valve banks (2) are provided with two sets respectively, the ports A5 of the two sets of pitch valve banks (2) are communicated, and the ports B2 of the two sets of pitch valve banks (2) are communicated.

9. A lifting device comprising a pitch ram (1) for driving a boom of a construction machine to perform a pitching motion, characterized by further comprising an energy recovery control system according to any of claims 1-8.

10. Hoisting device according to claim 9, characterized in that the pitch cylinder (1) is arranged between the frame (7) and the boom (8), and that the angle between the axis of the pitch cylinder (1) and the horizontal plane varies between 0 and 90 degrees during operation.

Technical Field

The invention relates to the technical field of hoisting machinery, in particular to an energy recovery control system and hoisting equipment.

Background

When the suspension arm of the lifting equipment of the prior container reach stacker crane works in a pitching way, the suspension arm descends (bends) mainly by the dead weight of the suspension arm, other parts on the suspension arm and goods to push the pitching cylinder to retract, and an oil pump is basically not needed to supply oil to a rod cavity of the pitching cylinder to retract the cylinder. Therefore, the potential energy generated when the suspension arm descends is recycled, and the method has great practical significance for energy conservation and emission reduction when equipment is used.

In addition, when a heavy object is lifted, the pitching oil cylinder needs to be kept in a certain specific state, and in the currently disclosed pitching oil cylinder locking valve group, the general function is single, the fast/slow extension of the pitching oil cylinder cannot be flexibly realized, and the working condition adaptability is poor.

Disclosure of Invention

The technical problem to be solved by the invention is to overcome the defects of the prior art, and provide an energy recovery device, an energy recovery control system with the energy recovery device and hoisting equipment with the energy recovery control system, wherein potential energy generated when a hoisting arm of the hoisting equipment descends (bends) can be recovered and utilized according to selection, the position of the extended pitching oil cylinder can be conveniently locked, and the pitching oil cylinder can be extended quickly and slowly according to requirements, so that the quick and slow lifting of the hoisting arm can be realized

In order to solve the technical problems, the invention adopts the following technical scheme:

an energy recovery control system comprises a hydraulic oil pump, a hydraulic oil tank and a main control valve for controlling the extension and retraction of a pitching oil cylinder, wherein the main control valve is provided with an oil inlet A1, an oil return port T, a working oil port A2 and a working oil port B1, the oil inlet A1 is communicated with an oil outlet of the hydraulic oil pump, the oil return port T is communicated with the hydraulic oil tank, and an oil inlet of the hydraulic oil pump is communicated with the hydraulic oil tank; the energy recovery device and the pitching valve bank are further included;

the energy recovery device is provided with an A4 port communicated with an A5 port of the pitch valve group and an A3 port communicated with a working oil port A2 of the main control valve, and a working oil port B1 of the main control valve is communicated with a rod cavity of the pitch oil cylinder;

the energy recovery device comprises a first oil path and a second oil path which are arranged between an A4 port and an A3 port, a first control valve and a motor which are arranged on the first oil path, a power generation device which is in transmission connection with the motor, a power storage device which is electrically connected with the power generation device, and a second control valve which is arranged on the second oil path, wherein the first control valve is arranged between the A4 port and the A7 port of the motor; the second control valve is arranged between the port A8 of the motor and the port A4;

when the first control valve and the second control valve are electrified, the first control valve is communicated with the first oil way, and the second control valve closes the second oil way; when the first control valve and the second control valve are powered off, the first control valve closes the first oil way, and the second control valve is communicated with the second oil way;

the pitching valve group is provided with an A5 port communicated with an A4 port of the energy recovery device, an A6 port communicated with a rodless cavity of the pitching oil cylinder, a B3 port communicated with a rod cavity of the pitching oil cylinder, a B2 port communicated with a B1 port of the main control valve, and an oil drainage port T2 communicated with a hydraulic oil tank;

the pitching valve group comprises a second one-way valve; a third control valve; a one-way valve III; control valve four and logic valve;

the check valve II is arranged between the port A6 and the port B3 and is used for preventing hydraulic oil from flowing from the port A6 to the port B3;

the check valve III is arranged between the port B3 and the port B2 and is used for preventing hydraulic oil from flowing from the port B3 to the port B2;

the third control valve is arranged between the oil inlet of the second one-way valve and the oil inlet of the third one-way valve, and in a power-off state, hydraulic oil can flow to the oil inlet end of the second one-way valve and the port B3 through the third one-way valve and the third control valve at the same time; (ii) a

The logic valve is arranged between the port A5 and the port A6, the logic valve is provided with a first working port, a second working port and a control port, the first working port is communicated with the port A6, the second working port is connected with the port A5, and the control port is communicated with an oil inlet of the control valve IV;

and an oil outlet of the control valve IV is communicated with a port T2, and in a power-off state, hydraulic oil cannot flow from a control port of the logic valve to a port T2 through the control valve IV.

Therefore, whether an energy recovery function is implemented or not can be selected according to needs, when energy recovery is needed, the equipment suspension arm automatically descends (bends down) under the action of self weight by electrifying the control valve four in the pitching valve bank and controlling the main control valve, hydraulic oil in the rodless cavity of the pitching oil cylinder flows to the energy recovery device through the control valve A6 and the control valve A5 in the pitching valve bank, flows to the port A4 and the control valve I (electrified), the control valve II is closed (electrified), the hydraulic oil drives the motor to rotate, the motor drives the power generation device to work, electric energy generated by the power generation device is stored in the power storage device to be used by equipment, and the hydraulic oil in the motor flows back to the hydraulic oil tank through the check valve I and the. If the energy recovery is not needed, the control valve IV in the pitching valve group is communicated (electrified) with the control main control valve, when the suspension arm descends, the control valve I in the energy recovery device is closed (powered off), and the control valve II is communicated (powered off), so that hydraulic oil flows back to the hydraulic oil tank through the main control valve.

And the position of the extended oil cylinder can be locked or the pitch oil cylinder can be rapidly extended through the pitch valve group.

The principle of locking the position of the oil cylinder after the oil cylinder extends out through the pitching valve group is as follows: and the control valve IV is powered off to close the control valve IV, two working ports of the logic valve are not communicated, hydraulic oil in a rodless cavity of the pitching oil cylinder is blocked in the cavity, the hoisting arm driven by the pitching oil cylinder works within the range of 0-90 degrees, the pitching oil cylinder cannot extend out or retract when no operation action exists, and the hoisting arm is locked at a certain amplitude position. The realization principle of the quick extension of the pitching oil cylinder is as follows: in the pitching valve group, the control valve IV is communicated (electrified), the control valve III is communicated (electrified) in a one-way mode, hydraulic oil in a rod cavity in the pitching oil cylinder directly enters a rodless cavity of the pitching oil cylinder through the check valve II in the pitching valve group, the pitching oil cylinder is rapidly extended out, and the suspension arm of the driving device is rapidly lifted to work.

As a further improvement of the above technical solution:

the first oil path is also provided with a one-way valve I, the one-way valve I is arranged between an A8 port of the motor and the control valve II and the A3 port, and the one-way valve I is used for preventing hydraulic oil from flowing to the motor from the A3 port and the control valve.

The first control valve is a two-position two-way electromagnetic valve which is in a closed state when power is off and can enable hydraulic oil in a communicated state to flow in a two-way or one-way mode when power is on.

And the second control valve is a two-position two-way electromagnetic valve which is in a communicated state when the power is off and is in a closed state when the power is on and hydraulic oil can flow in two directions.

The pitching valve group further comprises a throttling device and an overpressure protection valve, wherein the throttling device comprises a first throttling valve and a second throttling valve;

the overpressure protection valve is arranged between a first working port of the logic valve and an oil outlet of the control valve IV, and an overflow oil port of the overpressure protection valve is communicated with a port T2;

the first throttling valve is arranged between a control port of the logic valve and an oil inlet of the control valve IV, one oil port of the second throttling valve is communicated with an oil inlet of the overpressure protection valve, and the other oil port of the second throttling valve is communicated with an oil outlet of the first throttling valve and an oil inlet of the control valve IV.

The realization principle of the slow extension of the pitching oil cylinder is as follows:

in the pitching valve group, the control valve IV is communicated (electrified), the control valve III is communicated (powered off) in two directions, hydraulic oil in a rod cavity in the pitching oil cylinder directly flows back to the oil tank through the control valve III and the main control valve, the pitching oil cylinder is extended out at a low speed, and the suspension arm of the equipment is driven to ascend at a low speed.

The control valve III is a two-position two-way electromagnetic valve which is in a two-way communication state when power is off and in a one-way communication state when power is on.

And the control valve IV is a two-position two-way electromagnetic valve which is in a closed state when power is off and in a communicated state when power is on and hydraulic oil can only flow to one direction.

The pitching oil cylinder is provided with two pitching valve banks, the pitching valve banks are correspondingly provided with two sets, ports A5 of the two sets of pitching valve banks are communicated, and ports B2 of the two sets of pitching valve banks are communicated.

As a general inventive concept, the invention also provides hoisting equipment, which comprises a pitching oil cylinder for driving the boom of the engineering mechanical equipment to do pitching motion, and the energy recovery control system.

As a further improvement of the above technical solution:

the pitching oil cylinder is arranged between the frame and the suspension arm, an included angle between the central axis of the pitching oil cylinder and the horizontal plane is changed from 0 degree to 90 degrees, the cylinder barrel end of the pitching oil cylinder is arranged on the frame, and the piston rod end of the pitching oil cylinder is arranged on the suspension arm.

Compared with the prior art, the invention has the advantages that:

(1) the energy recovery control system provided by the invention can conveniently collect and utilize potential energy generated when the suspension arm descends (bends) to work, and has great practical significance for energy conservation and emission reduction when equipment is used.

(2) The energy recovery control system provided by the invention can freely select whether the energy needs to be collected or not according to the needs so as to widen the working condition adaptability of the whole equipment.

(3) The energy recovery control system provided by the invention can conveniently realize the position locking of the extended pitching oil cylinder, and can realize the fast/slow extension of the pitching oil cylinder according to the requirement, thereby realizing the fast/slow extension of the suspension arm and widening the working condition adaptability of the whole equipment.

Drawings

Fig. 1 is a schematic diagram of an energy recovery control system and a hoisting device according to embodiment 1 of the present invention.

Fig. 2 is a schematic diagram of an energy recovery device of an energy recovery control system and a hoisting device according to the present invention.

Fig. 3 is a schematic diagram of a pitch valve set of an energy recovery control system and a hoisting device according to the present invention.

Fig. 4 is a schematic diagram of an energy recovery control system and a hoisting device according to embodiment 2 of the present invention.

Detailed Description

The invention is further described below with reference to specific preferred embodiments, without thereby limiting the scope of protection of the invention.

Example 1:

as shown in fig. 1, the lifting apparatus of the present embodiment includes a frame 7, a boom 8, a pitch cylinder 1 for driving the boom of the lifting apparatus to descend (pitch), and an energy recovery control system of the present embodiment. When the pitching oil cylinder works, the included angle between the central axis of the pitching oil cylinder 1 and the horizontal plane is changed from 0 degree to 90 degrees. Specifically, the cylinder end of the pitching oil cylinder 1 is installed on a frame of the hoisting equipment, and the piston rod end is installed on a suspension arm of the hoisting equipment.

The energy recovery control system comprises a hydraulic oil pump 5, a hydraulic oil tank 6, a main control valve 4 for controlling the extension and retraction of the pitching oil cylinder 1, an energy recovery device 3 capable of collecting energy generated when the pitching oil cylinder 1 retracts, and a pitching valve group 2 capable of achieving rapid and slow extension of the pitching oil cylinder and locking of the position of the extended oil cylinder.

The main control valve 4 is provided with an oil inlet A1, an oil return port T, a working oil port A2 and a working oil port B1, the oil inlet A1 is communicated with an oil outlet of the hydraulic oil pump 5, the oil return port T is communicated with the hydraulic oil tank 6, and the oil inlet of the hydraulic oil pump 5 is communicated with the hydraulic oil tank 6.

The pitch valve group 2 has an a5 port communicating with an a4 port of the energy recovery device, an a6 port communicating with a rodless chamber of the pitch cylinder 1, a B3 port communicating with a rod chamber of the pitch cylinder 1, a B2 port communicating with a B1 port of the main control valve 4, and a drain port T2 communicating with the hydraulic oil tank 6.

The energy recovery device has an a4 port that communicates with the a5 port of the pitch valve group 2, and an A3 port that communicates with the a2 port of the main control valve 4.

As shown in fig. 2, the energy recovery device includes a first oil path and a second oil path arranged between a port a4 and a port A3, a first control valve 31, a motor 34 and a first check valve 35 arranged on the first oil path, a power generation device 32 in transmission connection with the motor 34, a power storage device 33 electrically connected with the power generation device 32, and a second control valve 36 arranged on the second oil path, wherein the first control valve 31 is arranged between the port a4 and a port a7 of the motor 34; the second control valve 36 is disposed between the port A8 of the motor 34 and the port A4. . The first check valve 35 is arranged between the port A8 of the motor 34 and the port A3 of the control valve II 36, and the first check valve 35 is used for preventing hydraulic oil from flowing to the motor 34 from the port A3 and the port A3.

When the first control valve 31 and the second control valve 36 are electrified, the first control valve 31 is communicated with the first oil way, and the second control valve 36 closes the second oil way; when the first control valve 31 and the second control valve 36 are powered off, the first control valve 31 closes the first oil passage, and the second control valve 36 communicates with the second oil passage.

In this embodiment, the first control valve 31 is a two-position two-way electromagnetic valve which is in a closed state when power is off and is in a communicated state when power is on and can allow hydraulic oil to flow bidirectionally or unidirectionally; the second control valve 36 is a two-position two-way electromagnetic valve which is in a communication state when power is off and is in a closing state when power is on and hydraulic oil can flow in two directions.

As shown in fig. 3, the pitch valve group 2 includes a second check valve 22, a third control valve 21, a third check valve 26, a fourth control valve 27, an overpressure protection valve 23, a throttling device 24, and a logic valve 25.

The second check valve 22 is disposed between the port A6 and the port B3, and hydraulic oil can only flow from the port B3 to the port A6.

The check valve III 26 is arranged between the port B3 and the port B2, and hydraulic oil can only flow from the port B2 to the port B3.

The third control valve 21 is arranged between the second check valve 22 and the oil inlet of the third check valve 26, and in a non-electrified state,

hydraulic oil can simultaneously flow to the oil inlet end of the second check valve 22 and the port B3 through the third check valve 26 and the third control valve 21. The logic valve 25 is arranged between the port A5 and the port A6, the first working port 251 is communicated with the port A6, the second working port 252 is connected with the port A5, and the control port 253 is communicated with an oil inlet of the control valve IV 27;

the overpressure protection valve 23 is arranged between the first working oil port 251 of the logic valve 25 and the oil outlet of the control valve IV 27, and the overflow oil port is communicated with a port T2.

The first throttle valve 241 in the throttling device 24 is arranged between the control port 253 of the logic valve 25 and the oil inlet of the control valve IV 27, and the second throttle valve 242 in the throttling device 24 is arranged between the oil inlet of the overpressure protection valve 23 and the oil outlet of the first throttle valve 241 and the oil inlet of the control valve IV 27.

The fourth control valve 27 is arranged between the oil outlet end of the throttling device 24 and the overflow oil port of the overpressure protection valve 23, the oil outlet of the fourth control valve 27 is communicated with the port T2, and in a non-electrified state, hydraulic oil cannot flow from the oil outlet of the throttling device 24 to the port T2 through the fourth control valve 27.

In this embodiment, the control valve iii 21 is a two-position two-way electromagnetic valve that is in a two-way communication state when de-energized and in a one-way communication state when energized. The control valve IV 27 is a two-position two-way electromagnetic valve which is in a closed state when power is off and in a communicated state when power is on and hydraulic oil can only flow to one direction.

According to the energy recovery control system provided by the invention, the control valve IV 27 in the pitching valve group 2 is electrified and controls the main control valve 4, the equipment boom automatically descends (bends) under the action of self weight, hydraulic oil in a rodless cavity of the pitching cylinder 1 flows through A6 and A5 in the pitching valve group 2 to the energy recovery device 3, flows through an A4 port and a control valve I31 (electrified), the control valve II 36 is closed (electrified), the hydraulic oil drives the motor 34 to rotate, the motor 34 drives the power generation device 32 to work, electric energy generated by the power generation device 32 is stored in the power storage device 33 for equipment use, and the hydraulic oil in the motor 34 flows back to the hydraulic oil tank 6 through the check valve I35 and the main control valve 4.

The energy recovery control system provided by the invention can select whether an energy recovery function needs to be implemented or not according to needs, if the energy recovery is not needed, a control valve IV 27 in the pitching valve group 2 is communicated (electrified) with the control main control valve 4, when the suspension arm descends, a control valve I31 in the energy recovery device 3 is closed (powered off), and a control valve II 36 is communicated (powered off) to enable hydraulic oil to flow back to the hydraulic oil tank 6 through the main control valve 4.

The energy recovery control system provided by the invention can also lock the position of the oil cylinder after the oil cylinder extends out through the pitching valve group. Namely: the control valve IV 27 is powered off to close the control valve IV 27, the two working ports 251 and 252 of the logic valve 25 are not communicated, the hydraulic oil in the rodless cavity of the pitch cylinder 1 is sealed in the cavity, the boom 8 driven by the pitch cylinder 1 works in the range of 0 to 90 degrees, the pitch cylinder 1 cannot extend out or retract when no operation is performed, and the boom 8 is locked at a certain amplitude position. The energy recovery control system provided by the invention can also realize the quick lifting work of the suspension arm. Namely:

the control valve IV 27 is communicated (electrified), the control valve III 21 is communicated (electrified) in a one-way mode, hydraulic oil in a rod cavity in the pitching oil cylinder 1 directly enters a rodless cavity of the pitching oil cylinder 1 through the check valve II 22 in the pitching valve group 2, the pitching oil cylinder 1 is rapidly extended out, and the suspension arm 8 of the driving device is rapidly lifted to work.

The energy recovery control system provided by the invention can also realize the slow-speed lifting work of the suspension arm. Namely:

the control valve IV 27 is communicated (electrified), the control valve III 21 is communicated (deenergized) in two directions, hydraulic oil in a rod cavity in the pitching oil cylinder 1 directly flows back to the oil tank 6 through the control valve III 21 and the main control valve 4, slow stretching of the pitching oil cylinder 1 is realized, and the device boom 8 is driven to slowly raise.

Example 2:

as shown in fig. 4, in the lifting apparatus of this embodiment, two pitch cylinders 1 are provided, two sets of pitch valve banks 2 are correspondingly provided, ports a5 of the two sets of pitch valve banks 2 are communicated, and ports B2 of the two sets of pitch valve banks 2 are communicated. The rest of the structure is the same as in example 1.

The above description is only for the preferred embodiment of the present application and should not be taken as limiting the present application in any way, and although the present application has been disclosed in the preferred embodiment, it is not intended to limit the present application, and those skilled in the art should understand that they can make various changes and modifications within the technical scope of the present application without departing from the scope of the present application, and therefore all the changes and modifications can be made within the technical scope of the present application.