CN118579694A - A forklift and a forklift potential energy recovery system based on accumulator-assisted oil replenishment - Google Patents

Abstract

The invention provides a forklift and a forklift potential energy recovery system based on auxiliary oil supplement of an energy accumulator, and relates to the technical field of forklift driving. The forklift potential energy recovery system comprises a hydraulic oil tank, a first one-way valve, a hydraulic pump, a second one-way valve, a three-position three-way electromagnetic valve and a hydraulic oil cylinder which are sequentially connected. The rotating shaft of the hydraulic pump is connected with the motor in a transmission way. The oil return outlet of the three-position three-way electromagnetic valve is connected with the liquid inlet of the third one-way valve. The liquid outlet of the third one-way valve is connected with the inlets of the first two-position two-way electromagnetic valve and the second two-position two-way electromagnetic valve. The outlet of the first two-position two-way solenoid valve is coupled to the hydraulic port of the hydraulic accumulator. The outlet of the second two-position two-way electromagnetic valve is connected with the hydraulic oil tank. The inlets of the first two-position two-way electromagnetic valve and the second two-position two-way electromagnetic valve are connected with the inlet of the third two-position two-way electromagnetic valve. The outlet of the third two-position two-way electromagnetic valve is connected with the liquid inlet of the fourth one-way valve. The liquid outlet of the fourth one-way valve is connected with the liquid inlet of the hydraulic pump.

Description

A forklift and a forklift potential energy recovery system based on accumulator-assisted oil replenishment

Technical Field

The present invention relates to the technical field of forklift driving, and in particular to a forklift and a forklift potential energy recovery system based on accumulator-assisted oil replenishment.

Background Art

Forklifts have the characteristics of compact structure, easy operation, and flexible steering. As an indispensable part of the logistics system, they can operate stably in narrow and low environments, which makes them play an important role in the field of material handling.

The traditional power system of forklifts, especially internal combustion engines, not only consumes a lot of energy, but also pollutes the environment. The issue of energy efficiency has become increasingly prominent, especially in the context of rising energy costs. Improving the energy efficiency of forklifts has become an important demand of the industry. In order to meet these challenges, researchers have begun to explore the possibility of energy recovery in forklifts, especially the recovery and utilization of gravitational potential energy.

Nevertheless, the existing forklift lifting system still has deficiencies in terms of energy consumption, energy utilization and stability. In view of this, the applicant has specially proposed this application after studying the existing technology.

Summary of the invention

The present invention provides a forklift and a forklift potential energy recovery system based on accumulator-assisted oil replenishment, aiming to improve at least one of the above-mentioned technical problems.

In order to solve the above technical problems, the present invention provides a forklift potential energy recovery system based on accumulator-assisted oil replenishment, which includes a lifting oil circuit, a potential energy recovery oil circuit and an auxiliary oil replenishment oil circuit.

The lifting oil circuit includes a hydraulic oil tank. The hydraulic oil tank is connected to the liquid inlet of the first one-way valve. The liquid outlet of the first one-way valve is connected to the liquid inlet of the hydraulic pump. The rotating shaft of the hydraulic pump is connected to the motor. The liquid outlet of the hydraulic pump is connected to the liquid inlet of the second one-way valve. The liquid outlet of the second one-way valve is connected to the oil inlet of the three-position three-way solenoid valve. The working outlet of the three-position three-way solenoid valve is connected to the rodless chamber of the hydraulic cylinder, wherein the hydraulic cylinder is used to drive the fork to rise and fall.

The potential energy recovery oil circuit includes a third one-way valve, an energy storage assembly and a second two-position two-way solenoid valve. The energy storage assembly includes a first two-position two-way solenoid valve and a hydraulic accumulator. The return oil outlet of the three-position three-way solenoid valve is connected to the liquid inlet of the third one-way valve. The liquid outlet of the third one-way valve is connected to the inlet of the first two-position two-way solenoid valve and the second two-position two-way solenoid valve. The outlet of the first two-position two-way solenoid valve is connected to the hydraulic port of the hydraulic accumulator. The outlet of the second two-position two-way solenoid valve is connected to the hydraulic oil tank.

The auxiliary oil replenishment circuit includes a third two-position two-way solenoid valve and a fourth one-way valve. The third two-position two-way solenoid valve and the fourth one-way valve are connected in series between the inlets of the first two-position two-way solenoid valve and the second two-position two-way solenoid valve and the liquid inlet of the hydraulic pump.

As a further solution of the present invention, a control method of a forklift potential energy recovery system includes steps when the forklift is lifted and steps when the system performs energy recovery.

When the forklift is lifted, steps A1 to A3 are included.

A1. Determine whether the pressure in the hydraulic accumulator exceeds a first preset value.

A2. When it is determined that the pressure in the hydraulic accumulator exceeds the first preset value, the first two-position two-way solenoid valve and the third two-position two-way solenoid valve are opened to connect the hydraulic accumulator to the hydraulic inlet of the hydraulic pump for auxiliary oil replenishment. Otherwise, directly execute step A3.

A3. Connect the oil inlet and working outlet of the three-position three-way solenoid valve, and then the electric motor drives the hydraulic pump to supply the hydraulic oil in the hydraulic oil tank to the oil circuit. The hydraulic oil passes through the first one-way valve, the second one-way valve, and the three-position three-way solenoid valve into the rodless chamber of the hydraulic cylinder to realize the lifting movement of the forklift.

When the system performs energy recovery, it includes step B1 and step B2.

B1. Determine whether the load of the forklift exceeds a second preset value, and determine whether the pressure of the hydraulic accumulator is less than a third preset value.

B2. When it is determined that the load of the forklift does not exceed the second preset value, or when it is determined that the pressure of the hydraulic accumulator is not less than the third preset value, the working outlet of the three-position three-way solenoid valve is connected to the oil return outlet, and the second two-position two-way solenoid valve is opened to allow the hydraulic oil to flow directly back to the hydraulic oil tank through the second two-position two-way solenoid valve. Otherwise, the first two-position two-way solenoid valve is opened, and the working outlet of the three-position three-way solenoid valve is connected to the oil return outlet, so that the hydraulic oil in the rodless chamber of the hydraulic oil cylinder passes through the three-position three-way solenoid valve, the third one-way valve, and the first two-position two-way solenoid valve under the gravity potential energy of the cargo and enters the hydraulic accumulator to realize potential energy recovery.

As a further solution of the present invention, step B2 specifically includes steps B21 to B23.

B21. When it is determined that the load of the forklift exceeds the second preset value and the pressure of the hydraulic accumulator is less than the third preset value, it is further determined whether the difference between the pressure of the rodless chamber of the hydraulic cylinder and the pressure of the hydraulic accumulator exceeds a fourth preset value.

B22. When it is determined that the load of the forklift does not exceed the second preset value, or when it is determined that the pressure of the hydraulic accumulator is not less than the third preset value, or when it is determined that the difference between the pressure of the rodless chamber of the hydraulic cylinder and the pressure of the hydraulic accumulator does not exceed the fourth preset value, the working outlet and the oil return outlet of the three-position three-way solenoid valve are connected, and the second two-position two-way solenoid valve is opened to allow the hydraulic oil to flow directly back to the hydraulic oil tank through the second two-position two-way solenoid valve.

B23. When it is determined that the difference between the pressure of the rodless chamber of the hydraulic cylinder and the pressure of the hydraulic accumulator exceeds the fourth preset value, the two-position two-way solenoid valve connected to the hydraulic accumulator is opened, and the working outlet and the return oil outlet of the three-position three-way solenoid valve are connected, so that the hydraulic oil in the rodless chamber of the hydraulic cylinder passes through the three-position three-way solenoid valve, the third one-way valve, and the two-position two-way solenoid valve connected to the hydraulic accumulator under the gravitational potential energy of the cargo and enters the hydraulic accumulator to realize potential energy recovery.

As a further solution of the present invention, the forklift potential energy recovery system includes a plurality of the energy storage components, and the plurality of energy storage components are respectively provided with third preset values of different sizes. Wherein, during energy recovery, the potential energy is recovered from the plurality of energy storage components in order from large to small according to the size of the third preset value. Preferably, the number of energy storage components is two.

As a further solution of the present invention, the third preset value is provided with a plurality of pressure gears from large to small according to the number of hydraulic accumulators. The second preset value is provided with a plurality of pressure gears corresponding to the third preset value, wherein one pressure gear corresponds to one hydraulic accumulator.

As a further solution of the present invention, step B1 specifically includes steps B11 to B15.

B11. Obtain the forklift load value in real time.

B12, and obtaining a real-time pressure gear of a second preset value according to the load value, and when the load value of the forklift is less than the second preset value of the minimum pressure gear, determining that the load of the forklift does not exceed the second preset value.

B13. According to the real-time pressure level of the second preset value, obtain the corresponding pressure level of the third preset value.

B14. Determine whether the pressure of the hydraulic accumulator at or below the corresponding pressure gear is less than the set value of the corresponding gear.

B15. When it is determined that the pressure of the hydraulic accumulators at or below the corresponding pressure gear is not less than the set value of the corresponding gear, it is determined that the pressure of the hydraulic accumulator is not less than the third preset value. Otherwise, a hydraulic accumulator with a pressure less than the set value of the corresponding gear is obtained, and subsequent steps are performed in order from large to small according to the pressure gear, until the pressure of the hydraulic accumulator at the minimum pressure gear is less than the third preset value of the minimum pressure gear, and it is determined that the pressure of the hydraulic accumulator is not less than the third preset value.

As a further solution of the present invention, the lifting oil circuit further comprises a first overflow valve, the liquid inlet of the first overflow valve is connected to the liquid outlet of the hydraulic pump, and the liquid outlet of the first overflow valve is connected to the hydraulic cylinder.

As a further solution of the present invention, the lifting oil circuit further includes a throttle valve. The throttle valve is connected between the working outlet of the three-position three-way solenoid valve and the rodless chamber of the hydraulic cylinder.

As a further solution of the present invention, the number of the hydraulic cylinders is two, namely a first hydraulic cylinder and a second hydraulic cylinder. The first hydraulic cylinder and the second hydraulic cylinder are arranged in parallel, the rod chamber of the first hydraulic cylinder is connected to the rod chamber of the second hydraulic cylinder, and the rodless chamber of the first hydraulic cylinder is connected to the rodless chamber of the second hydraulic cylinder.

As a further solution of the present invention, the energy storage assembly further comprises a second overflow valve, the liquid inlet of the second overflow valve is connected to the hydraulic port of the hydraulic accumulator, and the liquid outlet of the second overflow valve is connected to the hydraulic oil tank.

As a further solution of the present invention, the rod chamber of the hydraulic cylinder is connected to the hydraulic oil tank.

The present application further provides a forklift, which includes a forklift potential energy recovery system based on accumulator-assisted oil replenishment as described in any paragraph of the first aspect.

By adopting the above technical solution, the present invention can achieve the following technical effects:

The forklift potential energy recovery system based on accumulator-assisted oil replenishment of the present invention introduces a hydraulic accumulator to realize the energy-saving technology of hydraulic oil replenishment and energy recovery on the basis of the hydraulic drive system jointly realized by the electric motor and the hydraulic pump, thereby further improving the energy recovery capacity of the forklift hydraulic system and realizing the stable operation of the system.

In addition, a two-position two-way solenoid valve is used to separate the potential energy recovery oil circuit under different oil pressures, and hydraulic accumulators with different initial pressures are selected to work according to different hydraulic oil pressures, realizing the coordinated operation of multiple hydraulic accumulators, reducing the loss of oil energy in the oil circuit and improving energy utilization.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

FIG. 1 is a schematic structural diagram of a forklift potential energy recovery system based on accumulator-assisted oil replenishment.

Markings in the figure: 1-hydraulic oil tank, 2-first one-way valve, 3-hydraulic pump, 4-motor, 5-first overflow valve, 6-second one-way valve, 7-three-position three-way solenoid valve, 8-throttle valve, 9-first hydraulic cylinder, 10-second hydraulic cylinder, 11-third two-position two-way solenoid valve, 12-third one-way valve, 13-first two-position two-way solenoid valve, 14-hydraulic accumulator, 15-second overflow valve, 16-second two-position two-way solenoid valve, 17-fourth one-way valve.

DETAILED DESCRIPTION

In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention claimed for protection, but merely represents the selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

Embodiment 1: As shown in FIG1 , an embodiment of the present invention provides a forklift potential energy recovery system based on accumulator-assisted oil replenishment, which comprises a lifting oil circuit, a potential energy recovery oil circuit and an auxiliary oil replenishment oil circuit.

The lifting oil circuit includes a hydraulic oil tank 1. The hydraulic oil tank 1 is connected to the liquid inlet of the first one-way valve 2. The liquid outlet of the first one-way valve 2 is connected to the liquid inlet of the hydraulic pump 3. The rotating shaft of the hydraulic pump 3 is connected to the motor 4. The liquid outlet of the hydraulic pump 3 is connected to the liquid inlet of the second one-way valve 6. The liquid outlet of the second one-way valve 6 is connected to the oil inlet of the three-position three-way solenoid valve 7. The working outlet of the three-position three-way solenoid valve 7 is connected to the rodless chamber of the hydraulic cylinder. The rod chamber of the hydraulic cylinder is connected to the hydraulic oil tank 1. Among them, the hydraulic cylinder is used to drive the fork to rise and fall.

As shown in FIG1 , based on the above embodiment, in an optional embodiment of the present invention, the number of the hydraulic cylinders is two, namely, a first hydraulic cylinder 9 and a second hydraulic cylinder 10. The first hydraulic cylinder 9 and the second hydraulic cylinder 10 are arranged in parallel, the rod chamber of the first hydraulic cylinder 9 is connected to the rod chamber of the second hydraulic cylinder 10, and the rodless chamber of the first hydraulic cylinder 9 is connected to the rodless chamber of the second hydraulic cylinder 10. Specifically, by setting up two hydraulic cylinders, the forklift's fork can be driven to lift and lower in a balanced manner, effectively avoiding the wear caused by the tilt of a single cylinder under force, and greatly improving the service life of the forklift.

As shown in FIG1 , preferably, the lifting oil circuit further includes a first relief valve 5 and a throttle valve 8. The throttle valve 8 is connected between the working outlet of the three-position three-way solenoid valve 7 and the rodless chamber of the hydraulic cylinder. The liquid inlet of the first relief valve 5 is connected to the liquid outlet of the hydraulic pump 3. The liquid outlet of the first relief valve 5 is connected to the hydraulic cylinder. In this embodiment, the liquid inlet of the first relief valve 5 is connected to the liquid inlet of the second one-way valve 6, and in other embodiments, the liquid inlet of the first relief valve 5 is connected to the liquid outlet of the second one-way valve 6. Specifically, the first relief valve 5 can effectively avoid excessive pressure in the lifting oil circuit. The throttle valve 8 can effectively adjust the lifting speed of the hydraulic cylinder to avoid sudden changes in the speed of the cylinder, thereby smoothly lifting and lowering, which has good practical significance.

The potential energy recovery oil circuit includes a third one-way valve 12, an energy storage assembly and a second two-position two-way solenoid valve 16. The energy storage assembly includes a first two-position two-way solenoid valve 13 and a hydraulic accumulator 14. The return oil outlet of the three-position three-way solenoid valve 7 is connected to the liquid inlet of the third one-way valve 12. The liquid outlet of the third one-way valve 12 is connected to the inlet of the first two-position two-way solenoid valve 13 and the second two-position two-way solenoid valve 16. The outlet of the first two-position two-way solenoid valve 13 is connected to the hydraulic port of the hydraulic accumulator 14. The outlet of the second two-position two-way solenoid valve 16 is connected to the hydraulic oil tank 1. Specifically, the gravitational potential energy of the cargo during descent can be converted into pressure energy in the hydraulic accumulator 14 through the energy storage assembly, which greatly reduces the energy loss.

As shown in FIG1 , based on the above embodiment, in an optional embodiment of the present invention, the energy storage assembly further includes a second relief valve 15. The liquid inlet of the second relief valve 15 is connected to the hydraulic port of the hydraulic accumulator 14. The liquid outlet of the second relief valve 15 is connected to the hydraulic oil tank 1. Specifically, the second relief valve 15 can prevent the pressure in the energy storage assembly from being too high.

The auxiliary oil replenishment circuit includes a third two-position two-way solenoid valve 11 and a fourth one-way valve 17. The third two-position two-way solenoid valve 11 and the fourth one-way valve 17 are connected in series between the inlets of the first two-position two-way solenoid valve 13 and the second two-position two-way solenoid valve 16, and the liquid inlet of the hydraulic pump 3.

In this embodiment, the inlet of the third two-position two-way solenoid valve 11 is connected to the inlet of the first two-position two-way solenoid valve 13 and the second two-position two-way solenoid valve 16. The outlet of the third two-position two-way solenoid valve 11 is connected to the liquid inlet of the fourth one-way valve 17. The liquid outlet of the fourth one-way valve 17 is connected to the liquid inlet of the hydraulic pump 3. It can be understood that it is equivalent to install the fourth one-way valve 17 at the inlet or outlet of the third two-position two-way solenoid valve 11, and both solutions belong to the protection scope of the present invention.

The forklift potential energy recovery system based on accumulator-assisted oil replenishment of the present invention introduces a hydraulic accumulator 14 to realize the energy-saving technology of hydraulic oil replenishment and energy recovery on the basis of the hydraulic drive system jointly realized by the electric motor 4 and the hydraulic pump 3, thereby further improving the energy recovery capability of the forklift hydraulic system and realizing the stable operation of the system.

On the basis of the above-mentioned embodiment, in an optional embodiment of the present invention, the control method of the forklift potential energy recovery system includes steps when the forklift is lifted and steps when the system performs energy recovery.

When the forklift is lifted, steps A1 to A3 are included.

A1. Determine whether the pressure in the hydraulic accumulator 14 exceeds a first preset value.

A2. When it is determined that the pressure in the hydraulic accumulator 14 exceeds the first preset value, the first two-position two-way solenoid valve 13 and the third two-position two-way solenoid valve 11 are opened to connect the hydraulic accumulator 14 to the hydraulic inlet of the hydraulic pump 3 for auxiliary oil replenishment. Otherwise, directly execute step A3.

A3. Connect the oil inlet and working outlet of the three-position three-way solenoid valve 7, and then the motor 4 drives the hydraulic pump 3 to supply the hydraulic oil in the hydraulic oil tank 1 to the oil circuit. The hydraulic oil passes through the first one-way valve 2, the second one-way valve 6, and the three-position three-way solenoid valve 7 and enters the rodless chamber of the hydraulic cylinder to realize the lifting movement of the forklift.

When the system performs energy recovery, it includes step B1 and step B2.

B1. Determine whether the load of the forklift exceeds the second preset value, and determine whether the pressure of the hydraulic accumulator 14 is less than the third preset value.

B2. When it is determined that the load of the forklift does not exceed the second preset value, or when it is determined that the pressure of the hydraulic accumulator 14 is not less than the third preset value, the working outlet of the three-position three-way solenoid valve 7 is connected to the oil return outlet, and the second two-position two-way solenoid valve 16 is opened, so that the hydraulic oil flows directly back to the hydraulic oil tank 1 through the second two-position two-way solenoid valve 16. Otherwise, the first two-position two-way solenoid valve 13 is opened, and the working outlet of the three-position three-way solenoid valve 7 is connected to the oil return outlet, so that the hydraulic oil in the rodless chamber of the hydraulic oil cylinder passes through the three-position three-way solenoid valve 7, the third one-way valve 12, and the first two-position two-way solenoid valve 13 under the gravity potential energy of the cargo and enters the hydraulic accumulator 14 to realize potential energy recovery. Preferably, step B2 specifically includes steps B21 to B23.

B21. When it is determined that the load of the forklift exceeds the second preset value and the pressure of the hydraulic accumulator 14 is less than the third preset value, it is further determined whether the difference between the pressure of the rodless chamber of the hydraulic cylinder and the pressure of the hydraulic accumulator 14 exceeds a fourth preset value.

B22. When it is determined that the load of the forklift does not exceed the second preset value, or when it is determined that the pressure of the hydraulic accumulator 14 is not less than the third preset value, or when it is determined that the difference between the pressure of the rodless chamber of the hydraulic cylinder and the pressure of the hydraulic accumulator 14 does not exceed the fourth preset value, the working outlet and the return oil outlet of the three-position three-way solenoid valve 7 are connected, and the second two-position two-way solenoid valve 16 is opened, so that the hydraulic oil flows directly back to the hydraulic oil tank 1 through the second two-position two-way solenoid valve 16.

B23. When it is determined that the difference between the pressure of the rodless chamber of the hydraulic cylinder and the pressure of the hydraulic accumulator 14 exceeds the fourth preset value, the two-position two-way solenoid valve connected to the hydraulic accumulator 14 is opened, and the working outlet and the return oil outlet of the three-position three-way solenoid valve 7 are connected, so that the hydraulic oil in the rodless chamber of the hydraulic cylinder passes through the three-position three-way solenoid valve 7, the third one-way valve 12, and the two-position two-way solenoid valve connected to the hydraulic accumulator 14 under the gravitational potential energy of the cargo and enters the hydraulic accumulator 14 to realize potential energy recovery.

Specifically, the forklift potential energy recovery system based on accumulator-assisted oil replenishment of the present invention adopts a hydraulic accumulator 14 to avoid throttling and overflow losses, greatly improving energy utilization, and effectively solving the problems of high energy consumption, low energy utilization, and unstable operation of traditional forklift lifting systems.

On the basis of the above embodiment, in an optional embodiment of the present invention, the forklift potential energy recovery system comprises a plurality of the energy storage components, and the plurality of energy storage components are respectively provided with third preset values of different sizes. Wherein, during energy recovery, the potential energy is recovered from the plurality of energy storage components in order from large to small according to the size of the third preset value. Preferably, the number of energy storage components is two.

On the basis of the above embodiment, in an optional embodiment of the present invention, the third preset value is provided with a plurality of pressure gears from large to small according to the number of hydraulic accumulators 14. The second preset value is provided with a plurality of pressure gears corresponding to the third preset value. One pressure gear corresponds to one hydraulic accumulator 14.

Specifically, the specific values of the first preset value, the fourth preset value, the second preset value of different pressure gears, and the third preset value of different pressure gears are set by those skilled in the art according to actual conditions, and the present invention does not make specific limitations on this.

Preferably, step B1 specifically includes steps B11 to B15.

B11. Obtain the forklift load value in real time.

B12, and obtaining a real-time pressure gear of a second preset value according to the load value, and when the load value of the forklift is less than the second preset value of the minimum pressure gear, determining that the load of the forklift does not exceed the second preset value.

B13. According to the real-time pressure level of the second preset value, obtain the corresponding pressure level of the third preset value.

B14. Determine whether the pressure of the hydraulic accumulator 14 at or below the corresponding pressure gear is less than the set value of the corresponding gear.

B15. When it is determined that the pressure of the hydraulic accumulator 14 at or below the corresponding pressure gear is not less than the set value of the corresponding gear, it is determined that the pressure of the hydraulic accumulator 14 is not less than the third preset value. Otherwise, a hydraulic accumulator 14 with a pressure less than the set value of the corresponding gear is obtained, and subsequent steps are performed in order from large to small according to the pressure gear, until the pressure of the hydraulic accumulator 14 at the minimum pressure gear is less than the third preset value of the minimum pressure gear, and it is determined that the pressure of the hydraulic accumulator 14 is not less than the third preset value.

Specifically, in the energy storage stage, according to the oil pressure in the rodless chamber of the hydraulic oil cylinder (i.e., the size of the load), all hydraulic accumulators 14 with pressure lower than the oil pressure are stored in sequence from high pressure to low pressure. In the release stage, a hydraulic accumulator 14 can be randomly selected for oil replenishment, or a hydraulic accumulator 14 with a pressure greater than the oil pressure can be selected for oil replenishment according to the oil pressure in the rodless chamber (i.e., the size of the load), thereby achieving energy saving. The selection of the hydraulic accumulator 14 during energy storage and release is made by those skilled in the art, and the present invention does not make any specific limitation on this.

In an embodiment of the present invention, a forklift potential energy recovery system based on accumulator-assisted oil replenishment is provided, wherein a plurality of hydraulic accumulators 14 are placed in parallel, and a two-position two-way solenoid valve is used to separate the potential energy recovery oil circuits under different oil pressures. Hydraulic accumulators 14 with different initial pressures are selected to work according to different hydraulic oil pressures, so that a plurality of hydraulic accumulators 14 can cooperate to recover the potential energy of heavy objects, reduce the loss of oil energy in the oil circuit, realize the maximum energy recovery, and greatly improve the energy utilization rate. The system relies on the electric motor 4 to drive the lifting movement. During the lifting process, the hydraulic accumulator 14 replenishes oil to the hydraulic pump 3, thereby realizing the lifting movement.

Embodiment 2: The present application further provides a forklift, which includes a forklift potential energy recovery system based on accumulator-assisted oil replenishment as described in any paragraph of the first aspect.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (10)

1. The forklift potential energy recovery system based on the auxiliary oil supplement of the energy accumulator is characterized by comprising a lifting oil way, a potential energy recovery oil way and an auxiliary oil supplement oil way;

The lifting oil way comprises a hydraulic oil tank (1); the hydraulic oil tank (1) is connected with the liquid inlet of the first one-way valve (2); the liquid outlet of the first one-way valve (2) is connected with the liquid inlet of the hydraulic pump (3); the rotating shaft of the hydraulic pump (3) is connected with the motor (4) in a transmission way; the liquid outlet of the hydraulic pump (3) is connected with the liquid inlet of the second one-way valve (6); the liquid outlet of the second one-way valve (6) is connected with the oil inlet of the three-position three-way electromagnetic valve (7); the working outlet of the three-position three-way electromagnetic valve (7) is connected with a rodless cavity of the hydraulic cylinder; the hydraulic cylinder is used for driving the fork to ascend and descend;

The potential energy recovery oil way comprises a third one-way valve (12), an energy storage component and a second two-position two-way electromagnetic valve (16); the energy storage component comprises a first two-position two-way electromagnetic valve (13) and a hydraulic energy accumulator (14); the oil return outlet of the three-position three-way electromagnetic valve (7) is connected with the liquid inlet of the third one-way valve (12); the liquid outlet of the third one-way valve (12) is connected with the inlets of the first two-position two-way electromagnetic valve (13) and the second two-position two-way electromagnetic valve (16); the outlet of the first two-position two-way electromagnetic valve (13) is connected with the hydraulic port of the hydraulic accumulator (14); the outlet of the second two-position two-way electromagnetic valve (16) is connected with the hydraulic oil tank (1);

the auxiliary oil supplementing oil way comprises a third two-position two-way electromagnetic valve (11) and a fourth one-way valve (17); the third two-position two-way electromagnetic valve (11) and the fourth one-way valve (17) are connected in series between inlets of the first two-position two-way electromagnetic valve (13) and the second two-position two-way electromagnetic valve (16) and a liquid inlet of the hydraulic pump (3);

the control method of the forklift potential energy recovery system comprises the following steps:

When the forklift lifts:

a1, judging whether the pressure in the hydraulic accumulator (14) exceeds a first preset value;

A2, when the pressure in the hydraulic accumulator (14) exceeds a first preset value, opening the first two-position two-way electromagnetic valve (13) and the third two-position two-way electromagnetic valve (11) so as to enable the hydraulic accumulator (14) to be communicated with a liquid inlet of the hydraulic pump (3) for auxiliary oil supplementing; otherwise, directly executing the step A3;

A3, communicating an oil inlet and a working outlet of a three-position three-way electromagnetic valve (7), and then driving a hydraulic pump (3) by a motor (4) to provide hydraulic oil in a hydraulic oil tank (1) for an oil way, wherein the hydraulic oil enters a rodless cavity of the hydraulic oil tank through a first one-way valve (2), a second one-way valve (6) and the three-position three-way electromagnetic valve (7) so as to realize lifting movement of a forklift;

when the system is recovering energy:

B1, judging whether the load of the forklift exceeds a second preset value and judging whether the pressure of the hydraulic accumulator (14) is smaller than a third preset value;

B2, when the load of the forklift is judged not to exceed a second preset value or the pressure of the hydraulic accumulator (14) is judged not to be smaller than a third preset value, communicating a working outlet and an oil return outlet of the three-position three-way electromagnetic valve (7), and opening a second two-position two-way electromagnetic valve (16) so that hydraulic oil directly flows back to the hydraulic oil tank (1) through the second two-position two-way electromagnetic valve (16);

otherwise, the first two-position two-way electromagnetic valve (13) is opened, and the working outlet and the oil return outlet of the three-position three-way electromagnetic valve (7) are communicated, so that hydraulic oil in the rodless cavity of the hydraulic oil cylinder passes through the three-position three-way electromagnetic valve (7) and the third one-way valve (12) under the gravitational potential energy of goods, and the first two-position two-way electromagnetic valve (13) enters the hydraulic accumulator (14) to realize recovery of potential energy.

2. The forklift potential energy recovery system based on auxiliary oil supplement of an energy accumulator according to claim 1, wherein the forklift potential energy recovery system comprises a plurality of energy storage components, and the energy storage components are respectively provided with third preset values with different sizes; and when energy is recovered, the potential energy is recovered from the large to the small to the plurality of energy storage components in sequence according to the third preset value.

3. The forklift potential energy recovery system based on auxiliary oil supplement of the energy accumulator according to claim 2, wherein the third preset value is provided with a plurality of pressure gears from large to small according to the number of the hydraulic energy accumulators (14); the second preset value is provided with a plurality of pressure gears corresponding to the third preset value; wherein one pressure gear corresponds to one hydraulic accumulator (14);

The step B1 specifically comprises the following steps:

b11, acquiring a load value of the forklift in real time;

B12, acquiring a real-time pressure gear of a second preset value according to the load value, and judging that the load of the forklift does not exceed the second preset value when the load value of the forklift is smaller than the second preset value of the minimum pressure gear;

b13, acquiring a corresponding pressure gear of a third preset value according to the real-time pressure gear of the second preset value;

b14, judging whether the pressure of the hydraulic accumulator (14) corresponding to the pressure gear or below is smaller than a set value of the corresponding gear;

B15, when judging that the pressure of the hydraulic accumulator (14) corresponding to the pressure gear and below is not smaller than the set value of the corresponding gear, judging that the pressure of the hydraulic accumulator (14) is not smaller than a third preset value;

Otherwise, acquiring the hydraulic accumulator (14) with the pressure smaller than the set value of the corresponding gear, and sequentially executing subsequent steps from large to small according to the pressure gear until the pressure of the hydraulic accumulator (14) in the minimum pressure gear is smaller than a third preset value of the minimum pressure gear, and judging that the pressure of the hydraulic accumulator (14) is not smaller than the third preset value.

4. The forklift potential energy recovery system based on auxiliary oil supplement of the energy accumulator of claim 1, wherein the step B2 specifically comprises:

b21, when the load of the forklift exceeds a second preset value and the pressure of the hydraulic accumulator (14) is smaller than a third preset value, further judging whether the difference value between the pressure of the rodless cavity of the hydraulic cylinder and the pressure of the hydraulic accumulator (14) exceeds a fourth preset value;

B22, when the load of the forklift is judged not to exceed a second preset value, or the pressure of the hydraulic accumulator (14) is judged not to be smaller than a third preset value, or the difference value between the pressure of the rodless cavity of the hydraulic cylinder and the pressure of the hydraulic accumulator (14) is judged not to exceed a fourth preset value, a working outlet and an oil return outlet of the three-position three-way electromagnetic valve (7) are communicated, and the second two-position two-way electromagnetic valve (16) is opened, so that hydraulic oil directly flows back to the hydraulic oil tank (1) through the second two-position two-way electromagnetic valve (16);

And B23, when the difference value between the pressure of the rodless cavity of the hydraulic cylinder and the pressure of the hydraulic accumulator (14) exceeds a fourth preset value, opening a two-position two-way electromagnetic valve connected with the hydraulic accumulator (14), and communicating a working outlet and an oil return outlet of the three-position three-way electromagnetic valve (7), so that hydraulic oil in the rodless cavity of the hydraulic cylinder passes through the three-position three-way electromagnetic valve (7), the third one-way valve (12) and the two-position two-way electromagnetic valve connected with the hydraulic accumulator (14) under the gravitational potential energy of goods to enter the hydraulic accumulator (14) to realize potential energy recovery.

5. A forklift potential energy recovery system based on accumulator assisted oil filling according to any one of claims 1 to 4, wherein the lifting oil circuit further comprises a first overflow valve (5); the liquid inlet of the first overflow valve (5) is connected with the liquid outlet of the hydraulic pump (3); the liquid outlet of the first overflow valve (5) is connected with the hydraulic oil cylinder.

6. A forklift potential energy recovery system based on accumulator assisted oil filling according to any one of claims 1 to 4, wherein the lifting oil circuit further comprises a throttle valve (8); the throttle valve (8) is connected between the working outlet of the three-position three-way electromagnetic valve (7) and the rodless cavity of the hydraulic oil cylinder.

7. The forklift potential energy recovery system based on auxiliary oil supplement of an accumulator according to any one of claims 1 to 4, wherein the number of hydraulic cylinders is two, namely a first hydraulic cylinder (9) and a second hydraulic cylinder (10); the first hydraulic cylinder (9) and the second hydraulic cylinder (10) are arranged in parallel, a rod cavity of the first hydraulic cylinder (9) is communicated with a rod cavity of the second hydraulic cylinder (10), and a rodless cavity of the first hydraulic cylinder (9) is communicated with a rodless cavity of the second hydraulic cylinder (10).

8. A fork truck potential energy recovery system based on auxiliary oil replenishment of an accumulator according to any one of claims 1 to 4, wherein the energy storage assembly further comprises a second overflow valve (15); the liquid inlet of the second overflow valve (15) is connected with the hydraulic port of the hydraulic accumulator (14); the liquid outlet of the second overflow valve (15) is connected with the hydraulic oil tank (1).

9. A forklift potential energy recovery system based on auxiliary oil replenishment of an accumulator according to any one of claims 1 to 4, wherein a rod cavity of a hydraulic cylinder is in communication with the hydraulic tank (1).

10. A forklift truck comprising a forklift truck potential energy recovery system based on accumulator assisted oil replenishment according to any one of claims 1 to 8.