CN102602852A - Hydraulic hybrid stacking machine - Google Patents

Abstract

The present invention provides a hydraulic hybrid forklift, which includes a lifting cylinder, a drive axle, a first hydraulic motor, a second hydraulic motor, a first hydraulic pump, an engine, a coupler and an accumulator, wherein the engine The power is output to the coupler, and the power output of the coupler drives the drive axle; the potential energy generated by the heavy object in operation drives the lifting cylinder to generate hydraulic energy, and the hydraulic energy drives the second hydraulic motor, The second hydraulic motor drives the first hydraulic pump to rotate, and the hydraulic energy generated by the second hydraulic pump is stored in the accumulator, and the accumulator drives the first hydraulic motor. A hydraulic motor outputs power to drive the coupler. Through the technical solution of the present invention, the potential energy recovery and utilization of the mast lowering is realized, and the recovered potential energy is used for starting the machine, lifting the mast short distance, etc., which can effectively save the energy consumption of the system, and at the same time solve the problem of hydraulic accessories. problems and reduce costs.

Description

Hydraulic hybrid power stacker

technical field

The invention relates to a stacker, in particular to an energy-saving stacker, in particular to a parallel hydraulic hybrid power stacker.

Background technique

Empty container stacker is a kind of operating equipment for periodic handling and stacking of containers. During the working process, it is necessary to frequently start braking and lift containers up and down. During the lowering process of the spreader, most of the potential energy is consumed in vain, without recycling, and the energy is wasted seriously. Moreover, the vehicle is started frequently during the operation process, resulting in low engine efficiency and high fuel consumption.

Traditional parallel hydraulic hybrid vehicles (such as buses, heavy trucks, loaders, etc.) recycle braking energy to save energy, that is, the motors connected in parallel are used as pumps during braking to fill the high-pressure accumulator and recover The high-pressure oil is then used to assist start-up.

Existing related technology mainly has following shortcoming:

1. Braking energy recovery must use a special variable variable pump-motor dual-purpose motor. Since the hydraulic hybrid technology is not yet mature, there are no standard accessories to choose from, and the hydraulic accessories of the hybrid are restricted.

2. When there are requirements on the braking distance and speed of the vehicle during braking, the control system will become very complicated, and there will be many additional control components.

3. The energy-saving effect is directly proportional to the braking frequency, and the energy-saving effect of ordinary vehicles is often not good.

When the mast of the stacker is lowered, the displacement of the hydraulic system is large but the pressure is low. It must be pressurized before it can be charged into the accumulator. The lowering speed of the mast is required to be adjustable, and the working characteristics cannot be affected when the liquid is filled.

The current hydraulic recovery schemes that can be used for reference include:

1. In the pressurized cylinder mode, the large-displacement low-pressure oil is replaced by the pressurized cylinder with high-pressure and small-displacement oil when the mast is lowered, and then charged into the accumulator. The disadvantage is that it is difficult to adjust the speed of the booster cylinder, and there is a shock when the two booster cylinders change direction.

2. Due to the large inertia and high pressure when the traveling vehicles brake, it is easy to fill the high-pressure accumulator with liquid. However, when the mast of the stacker is lowered, the oil pressure is low, and the traditional method is not suitable for the working conditions of the stacker.

Therefore, for the existing related technologies, the problems to be solved are as follows:

1. The gravitational potential energy drop of the mast is recovered, and the low-pressure oil is converted into high-pressure oil and then charged into the high-pressure accumulator;

2. The accumulator filling pressure is gradually changing, how to stabilize its pressure;

3. The lowering speed of the mast is different according to different working conditions, and it is required to be controllable;

4. The walking motor does not need a dual-purpose motor to realize universal use of accessories;

5. Utilization of hydraulic energy after recovery.

Contents of the invention

To solve at least one of the above technical problems, the present invention provides a hydraulic hybrid forklift.

The hydraulic hybrid power stacker provided by the present invention includes: a lifting cylinder, a drive axle, a first hydraulic motor, a second hydraulic motor, a first hydraulic pump, an engine, a coupler and an accumulator, wherein the engine power output to the coupler, and the power output of the coupler drives the drive axle; during work, the potential energy generated by the heavy object drives the lifting cylinder to generate hydraulic energy, and the hydraulic energy drives the second hydraulic motor, so The second hydraulic motor drives the first hydraulic pump to rotate, the hydraulic energy generated by the second hydraulic pump is stored in the accumulator, the accumulator drives the first hydraulic motor, and the first The output power of the hydraulic motor drives the coupler.

In this technical solution, the potential energy when the mast of the stacker is lowered can be recovered and reused, that is, the potential energy when the mast is lowered is converted into hydraulic energy by driving the lifting cylinder, and the energy is converted into hydraulic energy by the second hydraulic motor and the first hydraulic pump. The hydraulic energy in the form of low-pressure hydraulic oil generated by the lifting cylinder is converted into hydraulic energy in the form of high-pressure hydraulic oil, and stored in the accumulator, and then the hydraulic energy in the accumulator is used to drive the first motor, and then drive the stacker The driving axle makes the potential energy of the mast lowering be recovered and utilized, avoiding the energy waste caused by the waste of potential energy during the mast lowering process, which can reduce the energy consumption of the stacker and save costs.

Preferably, a gearbox is also included, and the gearbox transmits the output power of the engine to the coupler.

Alternatively, a gearbox is also included, and the gearbox transmits the output power of the coupler to the drive axle.

The engine, gearbox and coupler adopt the above two connection methods, which can not only meet the requirements of the present invention for recovering and utilizing the potential energy of the mast, but also realize the requirements of different working conditions.

In the above technical solution, preferably, a second hydraulic pump is further included, wherein the gearbox drives the second hydraulic pump to rotate, and the hydraulic energy generated by the second hydraulic pump drives the lifting cylinder to lift the heavy object.

In this technical solution, the engine and/or the first hydraulic motor can be used to output power through the gearbox to drive the second hydraulic pump, thereby driving the lifting cylinder to work. Therefore, the ability of the lifting cylinder to lift heavy objects can be further improved. Meet the requirements of different working conditions.

Preferably, the accumulator can also directly drive the lifting cylinder to lift the heavy object. With this technical scheme, the engine is not started during the short lifting action, and only the energy stored in the accumulator is used to drive the lifting oil cylinder, so as to realize energy saving, reduce the number of engine starts and prolong the life of the engine.

Preferably, a control valve is further included, through which the accumulator drives the first hydraulic motor and/or drives the lifting cylinder to lift the heavy object. In this technical solution, the use of the collected gantry potential energy can be controlled as required by using the control valve, and the collected gantry potential energy can be fully utilized.

Preferably, the second hydraulic motor is a large-displacement variable motor, and the first hydraulic pump is a small-displacement variable pump. In this technical solution, the linkage between the variable motor and the variable pump is used to recover the potential energy when the mast is lowered, and at the same time, the low-pressure and large-flow oil when the mast is lowered can be converted into high-pressure and small-flow oil, thereby converting the potential energy of the mast. The high-pressure hydraulic energy is stored in the accumulator; in addition, the variable motor can control the lowering speed of the mast to prevent accidents and hydraulic system overheating, and the variable pump can adjust the outlet as the pressure of the accumulator increases. Pressure, to solve the problem of accumulator filling pressure gradual change, to facilitate energy storage.

Preferably, a reversing valve is further included, and the reversing valve enables the lift cylinder to be selectively connected to the second hydraulic pump, the accumulator or the second hydraulic motor. In this technical solution, the reversing valve is used to realize the operation of the lifting cylinder and the storage of hydraulic energy, which is convenient to control and can be controlled according to working conditions and needs, and is low in cost and easy to implement.

Preferably, the reversing valve is a two-position four-way electromagnetic reversing valve. In this technical solution, the two-position four-way electromagnetic reversing valve is used for flexible control, and the two-position four-way electromagnetic valve can be in different positions by controlling whether the electromagnet in the two-position four-way electromagnetic valve is energized. When the electromagnet is not energized, the two-position four-way solenoid valve is in the position where the lifting cylinder is connected to the second hydraulic pump and directly connected to the accumulator oil circuit; when the electromagnet is energized, the two-position four-way solenoid valve is in the position of The position where the lift cylinder is connected to the oil circuit of the second hydraulic motor. Therefore, the use of two-position four-way solenoid valve can realize remote control and automatic control, and improve control accuracy and control flexibility.

Preferably, a relief valve is further provided between the inlet of the second hydraulic motor and the oil tank, and a filter is further provided at the outlet of the second hydraulic motor and the inlet of the first hydraulic pump, so The first hydraulic motor is a variable displacement motor. An overflow valve is also arranged between the inlet of the variable variable motor and the oil tank, which can effectively avoid potential safety hazards caused by excessive pressure in the variable variable motor, ensure the safety of the variable variable motor, and improve the reliability of the system; The outlet of the variable variable motor and the inlet of the variable variable pump are also provided with a filter, which can filter foreign matter in the oil in the system, making the oil in the mast potential energy recovery system cleaner, prolonging the service life of the system and reducing the failure; the motor also adopts a variable motor, and the speed of the motor can be adjusted according to the pressure and flow of the liquid medium in the accumulator to meet the requirements of different working conditions; in addition, during the working process of the stacker, the potential energy Waste is the main part of energy waste, the waste of braking energy is relatively small, and the effect of recovering braking energy is not obvious under the situation of recovering potential energy, so this application does not recover braking energy, because there is no need to recover braking energy. It can be recycled, so ordinary variable motors can be used instead of pump-motor double-acting motors, which reduces costs, and because of the use of ordinary variable motors, the accessories can be interchanged with other motors, realizing the universal use of accessories. The cost is further reduced and the problem of hydraulic fittings is solved.

In summary, through the technical solution of the present invention, the recovery and utilization of the potential energy when the mast is lowered is realized, and the recovered potential energy is used for starting the machine, lifting the mast for a short distance, and assisting the engine to travel, etc., which can effectively save the system. energy consumption and reduce costs.

Description of drawings

Fig. 1 is a schematic diagram of a hydraulic hybrid power stacker according to an embodiment of the present invention;

Fig. 2 is a schematic diagram of a hydraulic hybrid forklift according to another embodiment of the present invention.

Detailed ways

In order to understand the above-mentioned purpose, features and advantages of the present invention more clearly, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

In the following description, many specific details are set forth in order to fully understand the present invention, but the present invention can also be implemented in other ways different from those described here, therefore, the present invention is not limited to the specific embodiments disclosed below limit.

Fig. 1 is a schematic diagram of a hydraulic hybrid power forklift according to an embodiment of the present invention.

As shown in Figure 1, the present invention provides a hydraulic hybrid power stacker, including: a lifting cylinder 6, a drive axle 12, a first hydraulic motor 4, a second hydraulic motor 7, a first hydraulic pump 8, and an engine 1 , a coupler 3 and an accumulator, wherein the power output of the engine 1 is to the coupler 3, and the power output of the coupler 3 drives the second load drive axle;

The potential energy generated by the weight during work drives the lifting cylinder 6 to generate hydraulic energy, the lifting cylinder 6 drives the second hydraulic motor 7, and the second hydraulic motor 7 drives the first hydraulic pump 8 to rotate , the hydraulic energy generated by the second hydraulic pump 8 is stored in the accumulator 9, the accumulator 9 drives the first hydraulic motor 4, and the output power of the first hydraulic motor 4 drives the coupling Device 3.

In this technical solution, the potential energy when the mast of the stacker is lowered can be recovered and reused, that is, the potential energy when the mast connected to the first load-lift cylinder 6 is lowered is converted into hydraulic energy through the lift cylinder 6 , and converted into hydraulic energy by the second hydraulic motor 7 and the first hydraulic pump 8 and stored in the accumulator 9 . Then use the hydraulic energy in the accumulator 9 to drive the first hydraulic motor 4, and then drive the second load-drive axle 12, so that the potential energy of the mast's descent can be recovered and utilized, and the potential energy is consumed in vain during the mast's descending process. Energy waste is caused, which can reduce the energy consumption of the forklift and save costs.

Preferably, a gearbox 2 is also included, and the gearbox 2 transmits the output power of the coupler 3 to the drive axle 12 .

In this technical solution, the engine 1, the gearbox 2 and the coupler 3 are connected in this way, which can not only meet the requirements of the present invention for recovering and utilizing the potential energy of the mast, but also meet the requirements of different working conditions.

Preferably, a second hydraulic pump 5 is also included, wherein the gearbox 3 drives the second hydraulic pump 5 to rotate, and the hydraulic energy generated by the second hydraulic pump 5 drives the lifting cylinder 6 to lift heavy objects.

In this technical solution, the engine 1 and/or the first hydraulic motor 4 can be used to drive the second hydraulic pump 5 to rotate, so as to generate hydraulic energy to drive the lifting cylinder 6 to work. Therefore, the capacity of the lifting cylinder to lift heavy objects can be further improved. Ability to meet the requirements of different working conditions.

Preferably, the accumulator 9 can also directly drive the lifting cylinder 6 to lift the heavy object. With this technical solution, the engine 1 is not started during the short lifting action, and only the energy stored in the accumulator is used to drive the lifting oil cylinder, so as to realize energy saving, reduce the number of engine startups and prolong the service life of the engine.

Preferably, a control valve 10 is also included, through which the accumulator 9 drives the first hydraulic motor 4 and/or drives the lifting cylinder 6 to lift heavy objects. In this technical solution, the use of the collected gantry potential energy can be controlled as required by using the control valve 10, and the collected gantry potential energy can be fully utilized.

Preferably, the second hydraulic motor 7 is a large displacement variable motor, and the first hydraulic pump 8 is a small displacement variable pump. In this technical solution, the linkage between the variable motor 7 and the variable pump 8 is used to recover the potential energy when the mast is lowered, and at the same time, the low-pressure and large-flow oil when the mast is lowered can be converted into high-pressure and small-flow oil, thereby reducing the potential of the mast. It can be converted into high-pressure hydraulic energy and stored in the accumulator 9; in addition, the variable motor 7 can be used to control the lowering speed of the mast to prevent accidents and hydraulic system overheating. Adjust the outlet pressure to solve the problem of gradual change of accumulator 9 filling pressure and facilitate energy storage.

Preferably, the mast potential energy recovery system further includes a reversing valve 11, and the reversing valve 11 enables the lifting cylinder 6 to be selectively connected with the second hydraulic pump 5, the accumulator 9 or the second hydraulic pressure. The motor 7 is connected to the oil circuit. In this technical solution, the reversing valve 11 is used to realize the operation of the lifting cylinder 6 and the storage of hydraulic energy, which is convenient to control and can be controlled according to working conditions and needs, and is low in cost and easy to implement.

Further, the reversing valve 11 is a two-position four-way electromagnetic reversing valve. In this technical solution, the control of the two-position four-way electromagnetic reversing valve is flexible, and remote control and automatic control can be realized, thereby improving control precision and control flexibility. In this embodiment, the working process of the two-position four-way electromagnetic reversing valve 11 is: when the electromagnet is energized, the two-position four-way electromagnetic reversing valve 11 works in the left position. At this time, the lifting cylinder 6 and the second hydraulic motor 7 is connected, so as to recover the potential energy of the lowering of the mast; when the electromagnet stops being energized, the two-position four-way electromagnetic reversing valve 11 works in the right position. At this time, the lifting cylinder 6 is connected with the second hydraulic pump 5 to realize the lifting cylinder. 6, in this case, if the short-distance lifting of the lifting cylinder 6 is realized, it is not necessary to start the engine 1 and then drive the second hydraulic pump 5 to drive the work of the lifting cylinder 6, but only through the control valve 10, Connect the lifting cylinder 6 and the accumulator 9, and use the energy stored in the accumulator 9 to drive the lifting cylinder 6 for a short-term lifting, saving energy.

Preferably, a relief valve 14 is also provided between the inlet of the variable displacement motor 7 and the oil tank 13 . In this technical solution, the use of the overflow valve 14 can effectively avoid potential safety hazards caused by excessive pressure in the variable variable motor 7, ensure the safety of the variable variable motor 7, and improve the reliability of the system.

Preferably, a filter 15 is also provided at the outlet of the variable displacement motor 7 and the inlet of the variable displacement pump 8 . In this technical solution, the foreign matter in the oil in the system can be filtered, so that the oil in the mast potential energy recovery system is cleaner, the service life of the system is extended, and the failure of the system is reduced.

Preferably, preferably the motor 4 also adopts a variable displacement motor. In this way, the speed of the motor 4 can be adjusted according to the pressure and flow of the liquid medium in the accumulator to meet the requirements of different working conditions; in addition, during the working process of the stacker, the waste of potential energy is the main part of energy waste. The waste of energy is relatively small, and the effect of recovering braking energy is not obvious in the case of recovering potential energy, so this application does not recover braking energy. Since there is no need to recover braking energy, an ordinary variable variable motor 4 That is, instead of using a pump-motor double-acting motor, which reduces the cost, and because of the use of a common motor, the accessories can be interchanged with other motors, realizing the universal use of accessories, further reducing the cost, and solving the problem of hydraulic accessories question.

As shown in Figure 1, in this embodiment, the engine 1, the gearbox 2, and the coupler 3 are connected sequentially, the output shaft of the coupler 3 is mechanically connected with the drive axle 12 of the stacker, and the potential energy of the mast falling is recovered by a hydraulic recovery system. The form of high-pressure oil is stored in the accumulator. When the vehicle is started, the high-pressure oil drives the motor 4, and the motor 4 directly drives the driving axle 12 through the coupler. The accumulator 9 can also be used to lift the mast at a small height.

Specifically, the working mode of the stacker in each working condition is as follows:

Potential energy recovery when the gantry is lowered: the variable motor 7 is connected in series with the variable pump 8. When the gantry is lowered, the high-flow low-pressure oil is converted into low-flow high-pressure oil and stored in the accumulator 9. The variable pump 8 automatically adjusts the displacement according to the pressure change of the accumulator 9, and the output torque is constant. The displacement change of the variable motor 7 is used to adjust the speed of the lifting cylinder 6 to realize the recovery of potential energy when the mast is lowered.

Traditional working mode: the engine 1 directly drives the driving axle 12 through the transmission shaft after passing through the hydraulic torque converter and the reducer in the gearbox 2, without recovering braking energy. In the working process of the stacker, the waste of potential energy is the main part of energy waste, and the waste of braking energy is relatively small. The effect of recovering braking energy is not obvious in the case of recovering potential energy, so this embodiment does not control Kinetic energy recovery; since there is no need to recover braking energy, the walking system can use ordinary motors instead of pump-motor double-acting motors, which reduces the cost, and because of the use of ordinary motors, the accessories can be It can be interchanged with other motors to realize the universal use of accessories and further reduce the cost.

Hydraulic assisted walking mode: The accumulator 9 high-pressure oil starts the motor 4, and the motor 4 drives the whole vehicle to move. After the hydraulic drive ends, the traditional mechanical hydraulic drive is used for walking. The use of hydraulic starting saves the high fuel consumption caused by the sudden change of the engine's direct starting load, and improves the energy utilization efficiency.

Hydraulic walking mode: when reversing, inching, or walking for a short distance, it can be driven by the hydraulic motor 4 alone, and the engine does not need to increase speed or wait for speed to perform work, thereby achieving energy-saving effects.

Lifting working condition: When the stacker picks up the container on the container truck, the mast only needs to be lifted to a small height. At this time, the high-pressure oil in the accumulator 9 can be used to drive the lifting cylinder 6, and there is no need to start the stacker. High engine 1, save energy.

Fig. 2 is a schematic diagram of a hydraulic hybrid forklift according to another embodiment of the present invention.

As shown in Figure 2, in this embodiment, the coupler 3 is arranged between the engine 1 and the gearbox 2, the output shaft of the gearbox 2 is mechanically connected to the drive axle 12 of the stacker, and other structures and connections are the same as in the above-mentioned embodiment ,No longer. In this embodiment, the potential energy when the mast is lowered can also be recovered and utilized, so as to realize the purpose of the invention.

When the hydraulic hybrid power stacker is as shown in Figure 2, that is: the coupler 3 is arranged between the engine 1 and the gearbox 2, the output shaft of the gearbox 2 is mechanically connected with the drive axle 12 of the stacker, the The specific conditions of the various working conditions of the hydraulic hybrid power stacker are as follows:

Potential energy recovery when the gantry is lowered: the variable motor 7 is connected in series with the variable pump 8. When the gantry is lowered, the high-flow low-pressure oil is converted into low-flow high-pressure oil and stored in the accumulator 9. The variable pump 8 automatically adjusts the displacement following the pressure change of the accumulator 9, and the output torque is constant. The displacement change of the variable motor 7 is used to adjust the descending speed of the oil cylinder, realizing the recovery and utilization of the potential energy when the mast descends.

Traditional working mode: the engine 1 directly drives the drive axle 12 to travel through the transmission shaft after passing through the hydraulic torque converter and the reducer in the gearbox 2 . In the working process of the stacker, the waste of potential energy is the main part of energy waste, and the waste of braking energy is relatively small. The effect of recovering braking energy is not obvious in the case of recovering potential energy, so this embodiment does not control Kinetic energy recovery; since there is no need to recover braking energy, the walking system can use ordinary motors instead of pump-motor double-acting motors, which reduces the cost, and because of the use of ordinary motors, the accessories can be It can be interchanged with other motors to realize the universal use of accessories and further reduce the cost.

Hydraulically assisted walking mode: the high-pressure oil of the accumulator 9 starts the motor 4, and the motor 4 is driven by the high-pressure oil of the accumulator 9, and the driving force is transmitted to the drive axle 12 through the coupler 3 and the gearbox 2 to make the whole vehicle walk, and then The hydraulic drive is over, and the traditional mechanical hydraulic drive is used to drive. The use of hydraulic starting saves the high fuel consumption caused by the sudden change in load of the direct starting of the engine 1, and improves the energy utilization efficiency.

When the mast is lifted: the engine 1 drives the working pump 5 on the gearbox 2 to work, and the accumulator can also drive the motor 4 to work, and the power of the motor 4 is transmitted to the engine 1 to help the engine 1 work and reduce the load on the engine 1 , to achieve energy-saving effect.

When the forklift needs a large torque for walking: the motor 4 and the engine 1 work together to realize cooperative work and effectively utilize the energy of the accumulator 9 .

To sum up, through the technical solution of the present invention, the recovery and utilization of the potential energy when the mast is lowered is realized, and the recovered potential energy is used for starting the machine, lifting the mast for a short distance, assisting the engine to travel, etc., which can effectively save the cost of the system. Energy consumption, while solving the problem of hydraulic accessories, reducing costs.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (10)

1. A hydraulic hybrid power stacker, characterized in that it comprises: a lifting cylinder (6), a drive axle (12), a first hydraulic motor (4), a second hydraulic motor (7), a first hydraulic pump (8), engine (1), coupler (3) and accumulator (9), wherein, the power output of the engine (1) is to the coupler (3), and the power output of the coupler (3) drive the drive axle (12); The potential energy generated by the weight during work drives the lifting cylinder (6) to generate hydraulic energy, and the hydraulic energy drives the second hydraulic motor (7), and the second hydraulic motor (7) drives the first hydraulic motor (7). The hydraulic pump (8) rotates, the hydraulic energy generated by the second hydraulic pump (8) is stored in the accumulator (9), and the accumulator (9) drives the first hydraulic motor (4) , the first hydraulic motor (4) outputs power to drive the coupler (3). 2. The hydraulic hybrid power stacker according to claim 1, characterized in that it also includes a gearbox (2), and the gearbox (2) transmits the output power of the engine (1) to the coupler (3). 3. The hydraulic hybrid power stacker according to claim 1, characterized in that it also includes a gearbox (2), and the gearbox (2) transmits the output power of the coupler (3) to the drive Bridge (12). 4. The hydraulic hybrid power stacker according to claim 2 or 3, further comprising a second hydraulic pump (5), wherein the gearbox (2) drives the second hydraulic pump (5 ) rotates, and the hydraulic energy generated by the second hydraulic pump (5) drives the lifting cylinder (6) to lift the heavy object. 5. The hydraulic hybrid power stacker according to claim 4, characterized in that, the accumulator (9) can also drive the lifting cylinder (6) to lift heavy objects. 6. The hydraulic hybrid power stacker according to claim 5, characterized in that it further comprises a control valve (10), and the accumulator (9) drives the first hydraulic pressure through the control valve (10). The motor (4) rotates and/or drives the lifting cylinder (6) to lift the weight. 7. The hydraulic hybrid power stacker according to claim 4, characterized in that, the second hydraulic motor (7) is a large-displacement variable motor, and the first hydraulic pump (8) is a small-displacement variable motor Pump. 8. The hydraulic hybrid power stacker according to claim 4, characterized in that it further comprises a reversing valve (11), and the reversing valve (11) enables the lifting cylinder (6) to be selectively connected to The second hydraulic pump (5), the accumulator (9) or the second hydraulic motor (7) are connected. 9. The hydraulic hybrid power stacker according to claim 8, characterized in that, the reversing valve (11) is a two-position four-way electromagnetic reversing valve. 10. The hydraulic hybrid power stacker according to claim 4, characterized in that an overflow valve (14) is also provided between the inlet of the second hydraulic motor (7) and the oil tank (13), A filter (15) is also provided at the outlet of the second hydraulic motor (7) and the inlet of the first hydraulic pump (8), and the first hydraulic motor (4) is a variable displacement motor.

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