CN114835059A - Simulation optimization system of engineering forklift - Google Patents

Abstract

The invention discloses a simulation optimization system of an engineering forklift, which comprises a central processing module, a simulation module and a simulation module, wherein the central processing module is used for carrying out centralized data processing on the simulation optimization system of the engineering forklift; the work driving module is used for driving the engineering forklift to convey the object, and the power output module is used for providing a power source for the engineering forklift work driving module; the potential energy recycling module is used for recycling potential energy when the engineering forklift works; when the fork of the forklift descends, the energy accumulator is utilized to recover and store the potential energy, and the potential energy is released when the forklift lifts again to reduce the energy consumption of the hydraulic pump, so that the potential energy can be smoothly recovered under the working conditions of no load, half load and full load on the premise of not influencing normal lifting operation, the energy-saving effect is good, and the energy recovery and the reutilization are realized.

Description

A Simulation and Optimization System of Engineering Forklift

technical field

The invention relates to the technical field of engineering forklifts, in particular to a simulation and optimization system for engineering forklifts.

Background technique

The development of the modern logistics industry has led to a rapid increase in the production of mobile cranes and transport machinery, and the most widely used forklifts in the field of mobile cranes and transport machinery. A forklift is a special vehicle that is equipped with forks and can lift loads to a target height. Sometimes forklifts are also classified as construction machinery. As a vehicle, forklifts and battery trucks, tractors, dump trucks, and AGV trolleys are equivalent to industrial vehicles or loading and unloading vehicles. It is widely used in factories, warehouses, ports, airports and other places to realize mechanized loading and unloading, stacking and short-distance handling, which greatly improves production efficiency and is an indispensable equipment in the modern logistics industry.

The traditional forklift does not have an energy recovery module. When the fork rises, the power source provides hydraulic energy through the hydraulic pump to supply the goods rising, which is converted into the gravitational potential energy of the goods; when the forks descend, the gravitational potential energy of the goods is converted into hydraulic energy. . The traditional forklift does not fully consider the use of the hydraulic energy during the descent, but only allows it to flow back to the fuel tank and convert it into heat energy for consumption. While the energy is wasted, the temperature of the hydraulic system rises, which damages the service life of the components.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a simulation and optimization system for an engineering forklift. When the fork of the forklift is lowered, the accumulator is used to recover and store this part of the potential energy, and it is released when the forklift is lifted again to reduce the energy consumption of the hydraulic pump. Without affecting the normal lifting operation, the potential energy can be recovered smoothly under no-load, half-load and full-load conditions, and the energy saving effect is good, realizing energy recovery and reuse.

The object of the present invention can be realized through the following technical solutions:

A simulation and optimization system for an engineering forklift includes a central processing module, which is used for centralized data processing of the engineering forklift simulation and optimization system; a work drive module for driving the engineering forklift to convey objects, and a power output module for Provide a power source for the working drive module of the engineering forklift; the potential energy recovery module is used to recover and reuse the potential energy of the engineering forklift when it is working.

As a further solution of the present invention, the potential energy recovery module adopts an energy storage device to realize energy recovery.

As a further solution of the present invention: the energy storage device selects battery energy storage, flywheel energy storage or accumulator energy storage.

As a further solution of the present invention, the potential energy recovery module further includes a pressure relief control oil circuit composed of the third one-way valve and the third reversing valve.

As a further solution of the present invention: the work driving module includes a hydraulic cylinder, and the hydraulic cylinder is used for lifting control for lifting and lowering the goods.

As a further solution of the present invention: the working drive module also includes a reversing valve 1 and a reversing valve 2, the reversing valve 1 is used to control the oil feed circuit of the hydraulic cylinder, and the reversing valve 2 is used to control the accumulator. The feed oil circuit is controlled.

As a further solution of the present invention: the power output module includes a quantitative hydraulic pump and a prime mover, the prime mover controls the work of the quantitative hydraulic pump, and the quantitative hydraulic pump is used as the power source of the working drive module.

As a further scheme of the present invention: when the engineering forklift is working, when the forklift is in an unloaded state, the forklift does not generate gravitational potential energy when it goes down, and the potential energy recovery module recovers zero potential energy; The potential energy recovery module recovers the gravitational potential energy for subsequent lifting.

As a further solution of the present invention: the potential energy recovery module uses the recovered energy for the forklift truck, and the power output module assists the potential energy recovery module to provide the forklift truck's working power.

Beneficial effects of the present invention:

(1) When the fork is lowered, use the accumulator to recover and store this part of the potential energy, and release it when the forklift is lifted again to reduce the energy consumption of the hydraulic pump. On the premise of not affecting the normal lifting operation, no-load, half- Potential energy can be recovered smoothly under full load and full load conditions, and the energy saving effect is good, realizing energy recovery and reuse.

(2) The accumulator is selected as the energy storage mechanism in the system, so that the system does not continuously output the flow and pressure to do external work. At this time, setting the accumulator can reduce the power of the selected pump, thereby reducing the size of the pump. At the same time, it can supplement leakage and maintain constant pressure. For hydraulic systems that need to maintain pressure, the selection of accumulators can effectively reduce the waste of output power of the pump.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings.

Fig. 1 is the structural block diagram of the system of the present invention;

FIG. 2 is a schematic structural diagram of the energy saving system of the present invention.

In the picture: 1. Quantitative hydraulic pump; 2. Prime mover; 3. Hydraulic cylinder; 4. Cargo; 5. Accumulator; 6. Fuel tank 1; 7. Relief valve; 8. Fuel tank 2; 9. Reversing valve One; 10, reversing valve two; 11, one-way valve one; 12, one-way valve two; 13, one-way valve three; 14, three reversing valve.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1 , the present invention is a simulation and optimization system of an engineering forklift, including a central processing module, which is used for centralized data processing of the engineering forklift simulation and optimization system; a work drive module is used to drive the engineering forklift. The hydraulic cylinder 3 inserts the goods 4, and the power output module is used to provide a power source for the work drive module when the engineering forklift is inserting the goods 4; the potential energy recovery module is used for the engineering forklift to carry out the potential energy during operation. Recycle and reuse to improve the energy-saving effect of forklifts.

Please refer to Figure 2. The overall energy-saving system of the engineering forklift includes a quantitative hydraulic pump 1 as a power source. The quantitative hydraulic pump 1 is controlled by a power output module. The quantitative hydraulic pump 1 is connected to a prime mover 2, and a quantitative hydraulic pump 1 The overflow valve 7 is connected to the upper part, the oil tank two 8 is connected to the overflow valve 7, the quantitative hydraulic pump 1 is connected to the hydraulic oil tank one 6, and the one-way valve one 11 is arranged between the quantitative hydraulic pump 1 and the oil tank one 6, and the replacement A two-way valve 12 is arranged between the second valve 10 and the first reversing valve 9, the accumulator 5 is arranged between the second one-way valve 12 and the second reversing valve 10, and the third reversing valve 14 and the first reversing valve. 9 is connected, a check valve 3 13 is set between the reversing valve 3 14 and the fuel tank 1 6; the hydraulic cylinder 3 is used as an actuator to lift and insert the cargo 4. When the cargo 4 needs to rise, the reversing valve 1 9 works in the right position, the reversing valve 2 works in the lower position and closes, the output oil of the quantitative hydraulic pump 1 enters the rodless cavity of the hydraulic cylinder 3 through the reversing valve 1 9, the piston rod of the hydraulic cylinder 3 goes up, and the cargo 4 Lifting; when going down, the reversing valve one 9 works in the left position, the reversing valve two 10 is closed in the lower position, and the oil in the rodless cavity of the hydraulic cylinder 3 is pressed into the accumulator 5 under the action of the gravity of the cargo for storage, and the energy is stored. The hydraulic energy is absorbed by the accumulator 5 successfully; when it is lifted again, the reversing valve one 9 works in the right position, the reversing valve two 10 works in the upper position and opens, and the pressure oil in the accumulator 5 is released to the oil suction port of the quantitative hydraulic pump 1, Therefore, the pressure difference between the inlet and outlet of the quantitative hydraulic pump 1 is reduced, and the external power input is reduced, so as to achieve the purpose of energy saving.

There is a balance between recovering as much energy as possible and not affecting the normal descent of the fork. When the weight of the cargo is not large enough, the fork cannot smoothly complete the descending action due to the large resistance of the accumulator branch. Therefore, a pressure relief control oil circuit composed of a one-way valve three 13 and a reversing valve three 14 is added to the energy-saving system. When the fork is blocked from descending, the opening and closing control signal is determined to be open, and the reversing valve 3 14 works in the right position to open the pressure relief, so that the oil smoothly flows into the fuel tank and the cargo is successfully lowered.

In the above system, the central processing module is used to control the system as a whole, the work drive module is used to drive the hydraulic cylinder 3 to lift and control the cargo 4, and the power output module is used to drive the hydraulic cylinder 3 of the work drive module. Provide power hydraulic source, respectively control the amount of hydraulic oil absorbed by quantitative hydraulic pump 1, as well as the opening and closing control of reversing valve one 9 and reversing valve two 10, the potential energy recovery module is the hydraulic energy generated during the working process of the engineering forklift. The energy is recovered and stored by the accumulator 5, which is convenient to be released during the subsequent work of the forklift, thereby realizing the recovery and utilization of the working energy of the forklift and improving the energy utilization efficiency.

There are generally three types of energy storage devices 5, namely battery energy storage, flywheel energy storage and accumulator energy storage.

As an electric energy storage device, batteries have been widely studied and widely used in the field of energy saving of mobile machinery. Electric energy works stably, has no noise, has a wide range of applications and has clean emissions. Therefore, it is considered to be the most promising energy source to replace fossil energy. In the field of automobile energy saving, electric energy carrier batteries have been installed and mass-produced as energy storage devices in pure electric vehicles and hybrid electric vehicles, but there are two shortcomings: First, the current recoverable energy is not electric energy, so batteries are used as energy storage devices. There must be an energy conversion process when the device is installed. This conversion process is generally realized by a generator. The energy loss in this process is large, which directly affects the energy recovery efficiency. Secondly, the current battery life has not fully met people's expectations. The battery is not a perfect energy storage device until the technical bottleneck is completely solved.

As an energy storage device, the flywheel can achieve good energy recovery efficiency only in a very short working cycle. In addition, because of its large moment of inertia, the flywheel is more often used to smooth the fluctuation of the rotational speed.

In the hydraulic system of the forklift working device, the accumulator can directly absorb the pressure energy converted from the potential energy of the cargo 4, and its loss only depends on the temperature change. Only when there is a large temperature difference and a long time heat transfer will there be energy loss. There is no energy loss when the temperature stabilizes. Moreover, the cost of the accumulator is low, and the manufacturing technology is simple and mature. Therefore, it is selected as the energy storage device of the hydraulic system of the forklift working device.

When the fork is blocked from descending, the opening and closing control signal is determined to be open, and the reversing valve 3 14 works in the right position to open the pressure relief, allowing the oil to flow into the fuel tank smoothly, so that the cargo 4 can smoothly complete the descent. Therefore, the selection of the opening timing of the reversing valve three 14 is very important.

According to the calculation of the opening control of the reversing valve three 14, the pressure of the rodless cavity of the hydraulic cylinder is P _W when it goes down, the pressure of the accumulator branch is P _X ,

When P _W > P _X , the oil in the rodless cavity flows into the accumulator, and the fork goes down;

When P _W = P _X , the oil in the rodless cavity stops flowing into the accumulator, the fork stops descending, and the reversing valve 3 14 is opened to relieve pressure at this time;

When P _W < P _X , the fork stops descending, and the reversing valve 3 14 is opened to relieve pressure at this time;

Therefore, the opening conditions of the reversing valve three 14 are:

P _w -P _X ≤O

By adding two pressure sensors, the pressure of the rodless cavity of the hydraulic cylinder 3 and the pressure of the accumulator branch can be monitored in real time, and then through the control of the potential energy recovery module, the precise opening control of the reversing valve 3 14 can be achieved.

When the forklift is in the working process, it can be divided into different working states of no-load, half-load and full-load. According to the different working states of the forklift, the specific work projects of the corresponding energy-saving system are as follows:

1. No load

Lifting: reversing valve one 9 is in the right position, reversing valve two 10 is in the upper position and open, the accumulator 5 releases the pressure oil to the inlet of the quantitative hydraulic pump 1, and together with the quantitative hydraulic pump 1 drives the piston of the hydraulic cylinder 3 upward. If the previous working condition is half-load or full-load down, and the accumulator 5 recovers enough hydraulic energy, the lift can completely depend on the energy in the accumulator 5, and the power input of the prime mover 2 is basically zero.

Down: the first reversing valve 9 is in the left position, the second reversing valve 10 is in the lower position and closed, and the oil in the rodless cavity of the hydraulic cylinder 3 flows into the accumulator 5 through the second one-way valve 12 . Due to the low pressure in the rodless cavity at no-load, the pressure difference around the one-way valve 2 12 quickly drops to zero, the accumulator 5 cannot absorb the pressure oil, and the downward speed of the fork tends to zero. At this time, the controller of the reversing valve three 14 is determined to be open, the spool moves, the reversing valve three 14 works in the right position, the rodless cavity of the hydraulic cylinder 3 and the fuel tank one 6 are connected, and the fork descending is successfully completed.

Second, half load

Lifting: reversing valve one 9 is in the right position, reversing valve two 10 is in the upper position and open, the accumulator 5 releases the pressure oil to the inlet of the quantitative hydraulic pump 1, and together with the quantitative hydraulic pump 1 drives the piston of the hydraulic cylinder 3 upward. If the previous working condition is full load down, and the accumulator 5 recovers enough hydraulic energy, the lift can completely depend on the energy in the accumulator 5, and the power input of the prime mover 2 is basically zero.

Down: the first reversing valve 9 is in the left position, the second reversing valve 10 is in the lower position and closed, and the oil in the rodless cavity of the hydraulic cylinder 3 flows into the accumulator 5 through the second one-way valve 12 . Because the pressure of the rodless cavity is not too large at half load, the pressure difference around the check valve 2 12 gradually drops to zero, the accumulator 5 can no longer absorb the pressure oil, and the downward speed of the fork tends to zero. At this time, the controller of the reversing valve three 14 is determined to be open, the spool moves, the reversing valve three 14 works in the right position, the rodless cavity of the hydraulic cylinder 3 and the fuel tank one 6 are connected, and the fork descending is successfully completed.

Three, full load

Lifting: reversing valve one 9 is in the right position, reversing valve two 10 is in the upper position and open, the accumulator 5 releases the pressure oil to the inlet of the quantitative hydraulic pump 1, and together with the quantitative hydraulic pump 1 drives the piston of the hydraulic cylinder 3 upward. Depending on the previous working conditions, the amount of reduction in the pressure difference between the inlet and outlet of the quantitative hydraulic pump 1 is different, and the amount of reduction in the power input of the prime mover 2 is also different.

Down: the first reversing valve 9 is in the left position, the second reversing valve 10 is in the lower position and closed, and the oil in the rodless cavity of the hydraulic cylinder 3 flows into the accumulator 5 through the second one-way valve 12 . When fully loaded, the pressure of the rodless cavity is large enough, and all the pressure oil in the rodless cavity enters the accumulator 5, the accumulator 5 recovers the maximum energy, and the fork descends smoothly. During this process, the pressure of the rodless cavity and the branch pressure of the accumulator 5 fail to meet the opening condition of the reversing valve 3 14, so the reversing valve 3 14 is always closed at the left position.

The purpose of the accumulator is to store energy in the hydraulic system and release it again when needed. It mainly has the following uses:

(1) As an auxiliary power source. Due to the working cycle of some hydraulic systems, the system does not continuously output the flow and pressure to do external work. At this time, setting the accumulator can reduce the power of the selected pump, thereby reducing the size of the pump.

(2) Supplement leakage and maintain constant pressure. For hydraulic systems that need to maintain pressure, the use of accumulators can effectively reduce the waste of output power of the pump.

(3) As an emergency power source. When the external power to drive the pump is suddenly interrupted by some uncontrollable factors and the system needs to complete the unfinished action, the accumulator can be used as an emergency supplementary power source.

(4) As a flow compensation device. For example, in a hydraulic system equipped with a differential cylinder, due to the unequal volume of the rod cavity and the rodless cavity, excess flow or lack of flow will be generated when the piston moves. At this time, the accumulator can effectively absorb and compensate for this part of the flow.

(5) Eliminate pulsation and reduce system shock. If the gear pump is used in the system and the number of teeth is small, the parameters such as pressure and flow of the system will fluctuate greatly. At this time, installing an accumulator can reduce or even eliminate oscillation.

Further, a potential energy recovery module can be installed on other power mechanisms of the forklift system, such as the forklift's walking system, to realize the energy recovery and utilization of the forklift.

Further, according to the modeling of each component of the system, the SimulationX simulation model of the potential energy recovery and utilization system of the forklift working device can be constructed;

The forklift data used in the simulation model are:

Rated lifting weight (kg) 3000

Load center distance (mm) 500

Maximum lifting height (mm) 3300

Maximum stroke of hydraulic cylinder (mm) 1650

Hydraulic cylinder bore (mm) 56

Piston rod diameter (mm) 45

Gear pump maximum speed (r/min) 2500

Gear pump displacement (m L/r) 16

Forklift mass (kg) 4700

Set the simulation time to 80S, during which the actions are:

1. First lift. That is, the lifting without the support of the accumulator that has recovered energy is consistent with the lifting action of the traditional non-energy-saving forklift;

2. Down. The process of this system is different from traditional non-energy-saving forklifts. When the fork goes down, the accumulator will recover and store the potential energy;

3. Energy saving lifting. This lift will be supported by an accumulator that has recovered energy, that is, the accumulator and the traditional power source together provide the energy required for the lifting action of the forklift.

Set the forklift to be fully loaded, and run the simulation to see that the system can successfully complete the first lift before 17S, the downward movement of 19-25S and the re-lifting action of 60-75S. The function of the reversing valve 1 9 is the downward auxiliary control, which is opened when needed so that the fork can smoothly descend under any load condition of the forklift. The action of the reversing valve 1 9 is normal. Since the fork can be smoothly completed without the valve opening the fork when the forklift is fully loaded, the valve is not opened when the forklift is fully loaded. The changes of the pressure and flow in the accumulator are adapted to the operating state of the fork: the accumulator is charged in the downward stage of the fork; the pressure and flow of the accumulator are released in the stage of lifting again to assist the power source to work.

Set the forklift to half-load and run the simulation to show that after the fork starts to descend, the descending action is blocked after a period of time due to the gradual increase in the pressure of the accumulator circuit, and then the reversing valve 19 is opened in time to release the pressure, so that the fork can successfully complete the descending . At half load, the demand for the fork to descend is priority, and the opening of the reversing valve 1 9 reduces the volume of oil that can be recovered by the accumulator to a large extent, and the flow that can be recovered is also greatly reduced.

Set the forklift to be unloaded, and the motion simulation can show that the pressure of the rodless cavity of the hydraulic cylinder is very low when the fork is unloaded, which is much lower than the pressure of the accumulator circuit. That is to open the pressure relief, only a very small part of the return oil from the hydraulic cylinder flows into the accumulator for recovery, and most of it flows back to the fuel tank through the pressure relief oil circuit of the reversing valve 19. The reversing valve 19 opens shortly after the fork goes down, Until the fork completes the lowering action, most of the return oil flows through this valve and returns to the fuel tank; when the forklift is unloaded, the oil volume in the accumulator changes very little, and the flow rate that can be recovered is very small, but from the energy consumption In terms of perspective, it is still better than traditional forklifts.

The simulation model of the potential energy recovery and utilization system of the forklift working device is established on the SimulationX software, and the operation process is divided into three working conditions—full load, half load and no load. The simulation results show that: the lifting hydraulic cylinder runs smoothly and normally; The potential energy recovery and release effect of the accumulator has reached the expectation; the power of the external input hydraulic pump is significantly reduced in the energy-saving lifting stage compared with the non-energy-saving lifting; The control design of the pressure relief oil circuit is reasonable. The power curve of the external input hydraulic pump is further processed, and the energy consumption data of the traditional non-energy-saving forklift and the energy-saving forklift in a single lift under three working conditions are compared. The energy saving rate of load lifting is 9.56%; the energy saving rate of no-load lifting is 8.68%. This system has better achieved the goal of potential energy recovery and reuse of forklift working devices.

An embodiment of the present invention has been described in detail above, but the content is only a preferred embodiment of the present invention, and cannot be considered to limit the scope of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still belong to the scope of the patent of the present invention.

Claims (9)

1. The simulation optimization system of the engineering forklift is characterized by comprising a central processing module, wherein the central processing module is used for carrying out centralized data processing on the simulation optimization system of the engineering forklift; the working driving module is used for driving the engineering forklift to convey the object; the power output module is used for providing a power source for the engineering forklift work driving module; and the potential energy recovery module is used for recovering and reusing potential energy of the engineering forklift during working.

2. The simulation optimization system of the engineering forklift as claimed in claim 1, wherein the potential energy recovery module adopts an energy storage device (5) to recover energy.

3. The simulation optimization system of the engineering forklift as claimed in claim 2, wherein the energy storage device (5) is selected from a storage battery, a flywheel or an energy storage device.

4. The simulation optimization system of the engineering forklift as claimed in claim 3, wherein the potential energy recovery module further comprises a pressure relief control oil path consisting of a check valve III (13) and a reversing valve III (14).

5. The simulation optimization system of the engineering forklift as claimed in claim 1, wherein the work driving module comprises a hydraulic cylinder (3), and the hydraulic cylinder (3) is used for lifting control of the goods (4).

6. The simulation optimization system of the engineering forklift as claimed in claim 5, wherein the working driving module further comprises a first reversing valve (9) and a second reversing valve (10), the first reversing valve (9) is used for controlling the feeding oil path of the hydraulic cylinder (3), and the second reversing valve (10) is used for controlling the feeding oil path of the energy accumulator (5).

7. The simulation optimization system of the engineering forklift as claimed in claim 1, wherein the power output module comprises a quantitative hydraulic pump (1) and a prime mover (2), the prime mover (2) controls the quantitative hydraulic pump (1) to work, and the quantitative hydraulic pump (1) is used as a power source of a work driving module.

8. The simulation optimization system of the engineering forklift as claimed in claim 1, wherein when the engineering forklift is in operation, when the forklift is in an idle state, the forklift does not generate gravitational potential energy when moving downwards, and the potential energy recovery module recovers the potential energy to zero; when the forklift is in a loading state, the forklift generates gravitational potential energy when moving downwards, and the potential energy recovery module recovers the gravitational potential energy for subsequent lifting.

9. The simulation optimization system of the engineering forklift as claimed in claim 8, wherein the potential energy recovery module is used for recovering energy for the forklift to work, and the power output module is used for assisting the potential energy recovery module to provide the forklift work power.

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