阅读说明：本技术 一种叉车液压控制系统 (Forklift hydraulic control system ) 是由 潘小军 于 2020-05-25 设计创作，主要内容包括：本发明公开了一种叉车液压控制系统,叉车包括货叉,该液压控制系统包括油箱、液压泵和用于控制货叉升降的升降液压缸,液压泵由马达驱动,液压泵的进油口和油箱相连通,液压泵的出油口连接有进油总管,升降液压缸的进油口通过第一进油支路和进油总管相连接,升降液压缸的出油口通过第一回油支路和回油总管相连接,回油总管和油箱相连通,第一回油支路上设置有比例阀,比例阀的阀口开度可调,液压泵的出油口通过压力过滤器和进油总管相连接。本发明能够方便地实现货叉下降速度的精准控制,使得货叉能够蠕动下降,提高了叉车的使用安全性。(The invention discloses a hydraulic control system of a forklift, wherein the forklift comprises a fork, the hydraulic control system comprises an oil tank, a hydraulic pump and a lifting hydraulic cylinder for controlling the lifting of the fork, the hydraulic pump is driven by a motor, an oil inlet of the hydraulic pump is communicated with the oil tank, an oil outlet of the hydraulic pump is connected with an oil inlet main pipe, an oil inlet of the lifting hydraulic cylinder is connected with the oil inlet main pipe through a first oil inlet branch, an oil outlet of the lifting hydraulic cylinder is connected with an oil return main pipe through a first oil return branch, the oil return main pipe is communicated with the oil tank, a proportional valve is arranged on the first oil return branch, the opening degree of a valve port of the proportional valve is adjustable, and the oil outlet of the hydraulic pump is connected with the oil inlet main pipe through a pressure filter. The invention can conveniently realize the accurate control of the descending speed of the fork, so that the fork can descend in a creeping manner, and the use safety of the forklift is improved.)

1. The utility model provides a fork truck hydraulic control system, fork truck includes the fork, its characterized in that, this hydraulic control system includes oil tank, hydraulic pump and is used for controlling the hydraulic cylinder that the fork goes up and down, the hydraulic pump is by motor drive, the oil inlet of hydraulic pump with the oil tank is linked together, the oil-out of hydraulic pump is connected with the oil feed house steward, hydraulic cylinder's oil inlet is connected with the oil feed house steward through first oil feed branch road, hydraulic cylinder's oil-out is connected with the oil return house steward through first oil return branch road, the oil return house steward with the oil tank is linked together, be provided with the proportional valve on the first oil return branch road, the valve port aperture of proportional valve is adjustable, the oil-out of hydraulic pump pass through pressure filter with the oil feed house steward is connected.

2. The forklift hydraulic control system of claim 1, wherein the pressure filter comprises a filtering inlet and a filtering outlet, the filtering inlet and the filtering outlet are communicated through a main channel, a filter element is arranged in the main channel, a differential pressure signaling device is connected between the filtering inlet and the filtering outlet, and the differential pressure signaling device is used for sending out a warning signal when the differential pressure between the filtering inlet and the filtering outlet reaches a warning value.

3. The forklift hydraulic control system of claim 2, wherein a bypass branch is further provided between the filtering inlet and the filtering outlet, and a bypass valve is provided on the bypass branch.

4. The forklift hydraulic control system of claim 1, wherein the pressure filter has a filtration accuracy of not more than 10 μm.

5. The forklift hydraulic control system of claim 1, wherein the first oil return branch is connected in parallel with a spare oil return branch, and a throttle valve is disposed on the spare oil return branch.

6. The forklift hydraulic control system of claim 1, wherein a pressure relief valve is connected between the oil intake manifold and the oil return manifold.

7. The forklift hydraulic control system of claim 1, wherein a first solenoid valve and a check valve are disposed on the first oil inlet branch, and the check valve is located between the hydraulic lift cylinder and the first solenoid valve.

8. The forklift hydraulic control system of claim 1, further comprising a forward-backward moving hydraulic cylinder and a second electromagnetic valve, wherein an oil inlet of the forward-backward moving hydraulic cylinder is connected with the oil inlet header pipe through a second oil inlet branch, an oil outlet of the forward-backward moving hydraulic cylinder is connected with the oil return header pipe through a second oil return branch, the second electromagnetic valve is a three-position four-way electromagnetic valve, the three-position four-way electromagnetic valve comprises four oil ports, two of the oil ports of the second electromagnetic valve are connected to the second oil inlet branch, and the other two of the oil ports are connected to the second oil return branch.

9. The forklift hydraulic control system of claim 8, further comprising a tilting hydraulic cylinder and a third electromagnetic valve, wherein an oil inlet of the tilting hydraulic cylinder is connected with the oil inlet header pipe through a third oil inlet branch, an oil outlet of the tilting hydraulic cylinder is connected with the oil return header pipe through a third oil return branch, the third electromagnetic valve also adopts a three-position four-way electromagnetic valve, the three-position four-way electromagnetic valve comprises four oil ports, two oil ports of the third electromagnetic valve are connected to the third oil inlet branch, the other two oil ports are connected to the third oil return branch, and a balance valve is further connected between the oil inlet and the oil outlet of the tilting hydraulic cylinder.

10. The forklift hydraulic control system of claim 8, further comprising a side-shifting hydraulic cylinder and a fourth electromagnetic valve, wherein an oil inlet of the side-shifting hydraulic cylinder is connected with the oil inlet header pipe through a fourth oil inlet branch, an oil outlet of the side-shifting hydraulic cylinder is connected with the oil return header pipe through a fourth oil return branch, the fourth electromagnetic valve also adopts a three-position four-way electromagnetic valve, the three-position four-way electromagnetic valve comprises four oil ports, two oil ports of the fourth electromagnetic valve are connected to the fourth oil inlet branch, and the other two oil ports are connected to the fourth oil return branch.

Technical Field

The invention relates to the technical field of forklifts, in particular to a hydraulic control system of a forklift.

Background

Fork truck is the wheeled haulage vehicle that is used for loading and unloading, stack and short distance transportation operation to the goods, is often used for the transportation of storage article. The forks are the main components of a forklift truck for forking and carrying goods. The existing forklift hydraulic system usually adopts a multi-way valve to control the descending of a pallet fork, a descending oil way only has two states of on and off, the descending speed of the pallet fork is not conveniently and accurately controlled, and if the operation is stopped suddenly when the pallet fork descends, large hydraulic impact is generated due to the fact that the descending speed is too fast, so that the shaking of a truck body is caused, and the use safety is low.

Disclosure of Invention

The invention aims to provide a forklift hydraulic control system, which can conveniently realize accurate control of the descending speed of a fork, so that the fork can descend in a creeping manner, the shaking of a forklift body caused by the excessively high descending speed of the fork is avoided, and the use safety is improved.

In order to solve the technical problems, the technical scheme provided by the invention is as follows:

the utility model provides a fork truck hydraulic control system, fork truck includes the fork, and this hydraulic control system includes oil tank, hydraulic pump and is used for control the hydraulic cylinder that the fork goes up and down, the hydraulic pump is by motor drive, the oil inlet of hydraulic pump with the oil tank is linked together, the oil-out of hydraulic pump is connected with the oil feed house steward, hydraulic cylinder's oil inlet is connected with the oil feed house steward through first oil feed branch road, hydraulic cylinder's oil-out is connected with the oil return house steward through first oil return branch road, the oil return house steward with the oil tank is linked together, be provided with the proportional valve on the first oil return branch road, the valve port aperture of proportional valve is adjustable, the oil-out of hydraulic pump pass through pressure filter with the oil feed house steward is connected.

In one embodiment, the pressure filter comprises a filtering inlet and a filtering outlet, the filtering inlet is communicated with the filtering outlet through a main channel, a filter element is arranged in the main channel, a differential pressure signaling device is connected between the filtering inlet and the filtering outlet, and the differential pressure signaling device is used for sending out a warning signal when the differential pressure between the filtering inlet and the filtering outlet reaches a warning value.

In one embodiment, a bypass branch is further disposed between the filtering inlet and the filtering outlet, and a bypass valve is disposed on the bypass branch.

In one embodiment, the pressure filter has a filtration precision of no greater than 10 μm.

In one embodiment, the first oil return branch is connected in parallel with a spare oil return branch, and a throttle valve is arranged on the spare oil return branch.

In one embodiment, a pressure relief valve is connected between the oil inlet main and the oil return main.

In one embodiment, a first electromagnetic valve and a one-way valve are arranged on the first oil inlet branch, and the one-way valve is located between the lifting hydraulic cylinder and the first electromagnetic valve.

In one embodiment, the hydraulic control system further comprises a forward-backward moving hydraulic cylinder and a second electromagnetic valve, an oil inlet of the forward-backward moving hydraulic cylinder is connected with the oil inlet header pipe through a second oil inlet branch, an oil outlet of the forward-backward moving hydraulic cylinder is connected with the oil return header pipe through a second oil return branch, the second electromagnetic valve adopts a three-position four-way electromagnetic valve, the three-position four-way electromagnetic valve comprises four oil ports, two oil ports of the second electromagnetic valve are connected to the second oil inlet branch, and the other two oil ports are connected to the second oil return branch.

In one embodiment, the hydraulic control system further comprises a tilting hydraulic cylinder and a third electromagnetic valve, an oil inlet of the tilting hydraulic cylinder is connected with the oil inlet header pipe through a third oil inlet branch, an oil outlet of the tilting hydraulic cylinder is connected with the oil return header pipe through a third oil return branch, the third electromagnetic valve also adopts a three-position four-way electromagnetic valve, the three-position four-way electromagnetic valve comprises four oil ports, two oil ports of the third electromagnetic valve are connected to a third oil inlet branch, the other two oil ports are connected to a third oil return branch, and a balance valve is further connected between the oil inlet and the oil outlet of the tilting hydraulic cylinder.

In one embodiment, the hydraulic control system further comprises a side shifting hydraulic cylinder and a fourth electromagnetic valve, an oil inlet of the side shifting hydraulic cylinder is connected with the oil inlet header pipe through a fourth oil inlet branch, an oil outlet of the side shifting hydraulic cylinder is connected with the oil return header pipe through a fourth oil return branch, the fourth electromagnetic valve also adopts a three-position four-way electromagnetic valve, the three-position four-way electromagnetic valve comprises four oil ports, two oil ports of the fourth electromagnetic valve are connected to the fourth oil inlet branch, and the other two oil ports are connected to the fourth oil return branch.

The invention has the following beneficial effects: the hydraulic control system for the forklift effectively realizes the accurate control of the descending speed of the fork, so that the fork can descend in a creeping manner, the hydraulic impact caused by the over-high descending speed of the goods is reduced, the shaking of a truck body caused by the hydraulic impact is avoided, and the descending stability of the goods and the use safety of the system are greatly improved.

Drawings

FIG. 1 is a schematic diagram of the hydraulic control system of the forklift truck according to the present invention;

in the figure: 1. the hydraulic control system comprises an oil tank, 2, a hydraulic pump, 3, a lifting hydraulic cylinder, 4, a motor, 5, a pressure filter, 51, a filter element, 52, a bypass valve, 53, a differential pressure signaling device, 6, an oil filter, 7, an oil inlet main pipe, 8, an oil return main pipe, 9, a first oil inlet branch, 10, a first oil return branch, 11, a standby oil return branch, 12, a second oil inlet branch, 13, a second oil return branch, 14, a third oil inlet branch, 15, a third oil return branch, 16, a fourth oil inlet branch, 17, a fourth oil return branch, 18, a proportional valve, 19, a throttle valve, 20, a pressure release valve, 21, a first electromagnetic valve, 22, a one-way valve, 23, a forward and backward hydraulic cylinder, 24, a tilting hydraulic cylinder, 25, a lateral shifting hydraulic cylinder, 26, a second electromagnetic valve, 27, a third electromagnetic valve, 28, a balance valve, 29 and a fourth electromagnetic valve.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

As shown in fig. 1, the embodiment discloses a forklift hydraulic control system, a forklift includes a movable fork, the hydraulic control system includes an oil tank 1, a hydraulic pump 2 and a hydraulic cylinder 3, the hydraulic cylinder 3 is used for controlling the fork to lift, the hydraulic pump 2 is driven by a motor 4, an oil inlet of the hydraulic pump 2 is communicated with the oil tank 1, an oil outlet of the hydraulic pump 2 is connected with an oil inlet main pipe 7, an oil inlet of the hydraulic cylinder 3 is connected with the oil inlet main pipe 7 through a first oil inlet branch 9, an oil outlet of the hydraulic cylinder 3 is connected with an oil return main pipe 8 through a first oil return branch 10, the oil return main pipe 8 is communicated with the oil tank 1, a proportional valve 18 is arranged on the first oil return branch 10, the opening of a valve port of the proportional valve 18 is adjustable, and an oil outlet of the hydraulic pump 2 is connected with the oil inlet main pipe 7 through a pressure filter 5.

Because the valve port aperture of proportional valve 18 is adjustable, different valve port apertures correspond different hydraulic oil flow, therefore, through set up proportional valve 18 on first oil return branch road 10, just can control the falling speed of fork through the valve port aperture of control proportional valve 18, make the fork can descend with the displacement amount accuracy of millimeter level, the peristaltic descent has been realized, also make the goods on the fork slowly descend until stopping with a reasonable rate of deceleration, avoided the goods to descend fast or stop suddenly and produce great hydraulic shock and inertia potential energy, this kind of great hydraulic shock and decline inertia potential energy release can make the whole car of automobile body produce obviously and rock, thereby cause the potential safety hazard.

The proportional valve 18 is an electric proportional valve, the opening of the valve port of the proportional valve 18 is controlled by a current signal input to the proportional valve 18, and the magnitude of the opening of the valve port of the proportional valve 18 and the magnitude of the current signal input to the proportional valve 18 are in a linear proportional relationship, so that the opening of the valve port of the proportional valve 18 can be controlled by controlling the magnitude of the current input to the proportional valve 18 by a controller on the forklift.

In addition, because the proportional valve 18 is sensitive to impurities in the oil, and excessive impurities can cause the valve core of the proportional valve 18 to be blocked to influence the opening adjustment of the valve port, the pressure filter 5 is arranged at the oil outlet of the hydraulic pump 2, the hydraulic oil output from the hydraulic pump 2 can be filtered through the pressure filter 5, and the pressure filter 5 has smaller pressure loss and higher filtering level, so that more tiny impurities in the oil and impurities generated by the chemical action of a medium can be further removed or blocked, and the normal operation of the proportional valve 18 is ensured.

In one embodiment, the pressure filter 5 has a filtration accuracy of not more than 10 μm for better filtration.

In one embodiment, an oil filter 6 is connected between the oil inlet of the hydraulic pump 2 and the oil tank 1 to filter the hydraulic oil entering the hydraulic pump 2 to prevent the valve plugs of the various valve banks from being blocked or stuck by impurities in the oil.

In one embodiment, the hydraulic pump 2 is a gear pump.

In one embodiment, the pressure filter 5 comprises a filter inlet (P)₁) And a filtration outlet (P)₂) Filtration inlet (P)₁) And a filtration outlet (P)₂) Are communicated with each other through a main channel, a filter element 51 and a filter inlet (P) are arranged in the main channel₁) And a filtration outlet (P)₂) A differential pressure signaling device 53 is connected between the two, the differential pressure signaling device 53 is used for filtering the inlet (P)₁) And a filtration outlet (P)₂) When the pressure difference reaches the alarm value, a warning signal is sent out. When filtering the inlet (P)₁) And a filtration outlet (P)₂) When the pressure difference is increased to the alarm value, it indicates that the filter element 51 is blocked, and at this time, the pressure difference signaling device 53 signals an alarm to remind the user to clean or replace the filter element.

Further, after the differential pressure signaling device 53 sends out the alarm signal, it needs to be manually reset to stop the alarm.

Further, the inlet (P) is filtered₁) And a filtration outlet (P)₂) Still be provided with the bypass branch road between, be provided with bypass valve 52 on the bypass branch road, after filter core 51 took place to block up, the main passage was difficult to the oil feed, and bypass valve 52 can open this moment for hydraulic oil passes through from the bypass branch road, thereby guarantees that whole hydraulic system can normal fuel feeding operation.

In one embodiment, a backup return branch 11 is connected in parallel to the first return branch 10, and a throttle 19 is provided in the backup return branch 11 to control the branch flow and thus the fork speed in place of the proportional valve 18 in the event of a failure of the proportional valve 18. Since the throttle valve 19 is a manual valve, the opening of the throttle valve 19 can be controlled by manual operation, so as to control the bypass flow. It will be appreciated that the throttle valve 19 is always closed when the proportional valve 18 is operating normally.

In one embodiment, a pressure release valve 20 is connected between the oil inlet main pipe 7 and the oil return main pipe 8, the pressure release valve 20 can be an electromagnetic valve, the pressure release valve 20 is powered all the time, a valve core in the pressure release valve has a set pressure value, and when the pressure difference between the oil inlet main pipe 7 and the oil return main pipe 8 exceeds the set pressure value, the valve core is opened to realize the unloading protection, so that the whole hydraulic system is prevented from being broken down due to overload.

In one embodiment, the first oil inlet branch 9 is provided with a first electromagnetic valve 21 and a check valve 22, and the check valve 22 is located between the hydraulic lifting cylinder 3 and the first electromagnetic valve 21. When the goods descend to return oil, if the goods is heavier, a larger oil return pressure can be generated, the pressure oil with the oil return pressure can impact the valve core of the first electromagnetic valve 21, the first electromagnetic valve 21 can be damaged seriously, in order to avoid the problem, the check valve 22 is additionally arranged at the front end of the first electromagnetic valve 21 so as to play a better protection role on the first electromagnetic valve 21, and the first electromagnetic valve 21 is used for controlling the on-off of the first oil inlet branch 9.

In one embodiment, the hydraulic control system of the forklift further comprises a forward and backward hydraulic cylinder 23 and a second solenoid valve 26, wherein the forward and backward hydraulic cylinder 23 is used for controlling the forward and backward movement of the pallet fork. An oil inlet of the forward-moving backward hydraulic cylinder 23 is connected with the oil inlet header pipe 7 through a second oil inlet branch pipe 12, an oil outlet of the forward-moving backward hydraulic cylinder 23 is connected with the oil return header pipe 8 through a second oil return branch pipe 13, the second electromagnetic valve 26 is a three-position four-way electromagnetic valve, and the three-position four-way electromagnetic valve comprises four oil ports (O)₁、O₂、O₃、O₄) Two ports (O) of the second solenoid valve 26₂、O₃) Connected to the second oil inlet branch 12, and the other two oil ports (O)₁、O₄) And the second oil return branch 13 is connected with the second oil inlet branch 12 and the second oil return branch 13, so that the second electromagnetic valve 26 is used for controlling the on-off of the second oil inlet branch 12 and the second oil return branch 13, and the forward movement or the backward movement of the pallet fork is realized.

In one embodiment, a forkliftThe hydraulic control system further comprises a tilt cylinder 24 and a third solenoid valve 27, the tilt cylinder 24 being adapted to control the tilting of the forks such that the forks are tilted by a certain angle. An oil inlet of the inclined hydraulic cylinder 24 is connected with the oil inlet main pipe 7 through a third oil inlet branch 14, an oil outlet of the inclined hydraulic cylinder 24 is connected with the oil return main pipe 8 through a third oil return branch 15, the third electromagnetic valve 27 also adopts a three-position four-way electromagnetic valve, and the three-position four-way electromagnetic valve comprises four oil ports (O)₁、O₂、O₃、O₄) Two ports (O) of the third solenoid valve 27₂、O₃) Connected to the third oil inlet branch 14, and the other two oil ports (O)₁、O₄) And a balance valve 28 is connected between the oil inlet and the oil outlet of the tilting hydraulic cylinder 24 and connected to the third oil return branch 15. The above-mentioned balancing valve 28 and the third solenoid valve 27 constitute a pressure maintaining circuit so that the fork can be maintained in a certain inclined state.

In one embodiment, the forklift hydraulic control system further comprises a side shift hydraulic cylinder 25 and a fourth solenoid valve 29, wherein the side shift hydraulic cylinder 25 is used for driving the fork to laterally shift left and right so as to facilitate the insertion and stacking of goods. An oil inlet of the side shifting hydraulic cylinder 25 is connected with the oil inlet header pipe 7 through a fourth oil inlet branch 16, an oil outlet of the side shifting hydraulic cylinder 25 is connected with the oil return header pipe 8 through a fourth oil return branch 17, the fourth electromagnetic valve 29 also adopts a three-position four-way electromagnetic valve, and the three-position four-way electromagnetic valve comprises four oil ports (O)₁、O₂、O₃、O₄) Two ports (O) of the fourth solenoid valve 29₂、O₃) Connected to the fourth oil inlet branch 16, and two other oil ports (O)₁、O₄) And the fourth oil return branch 17 is connected with the fourth oil inlet branch 16 and the fourth oil return branch 17, so that the fourth electromagnetic valve 29 is used for controlling the on-off of the fourth oil inlet branch 16 and the fourth oil return branch 17, and the transverse movement of the pallet fork to the left or the right is realized.

In one embodiment, the hydraulic cylinder 3 is a single-acting hydraulic cylinder, and the oil inlet and the oil outlet of the hydraulic cylinder are the same oil port.

The process of controlling the fork to lift by the hydraulic control system of this embodiment is described below by taking the single-acting hydraulic cylinder as an example of the lifting hydraulic cylinder 3: when the fork needs to be controlled to ascend, hydraulic oil output by the hydraulic pump 2 enters the oil inlet main pipe 7 after being filtered by the pressure filter 5 and enters the rodless cavity of the lifting hydraulic cylinder 3 through the first oil inlet branch 9 and the oil inlet of the lifting hydraulic cylinder 3, so that the piston rod of the lifting hydraulic cylinder is driven to extend out to push the fork to move upwards; when the fork needs to be controlled to descend, the first oil inlet branch 9 is closed, the proportional valve 18 on the first oil return branch 10 is opened, at the moment, hydraulic oil in the rodless cavity of the lifting hydraulic cylinder 3 flows into the first oil return branch 10 through an oil outlet (an oil inlet) of the lifting hydraulic cylinder 3, flows back to the oil return main pipe 8 through the first oil return branch 10, and returns to the oil tank through the oil return main pipe 8, and at the moment, the peristaltic descending of the fork can be realized only by controlling the opening degree of a valve port of the proportional valve 18. Through the process, the fork truck can realize the accurate descending control of the fork no matter in the no-load or full-load state. It will be appreciated that the proportional valve 18 is only activated to open when the load is lowered back into the oil.

According to the hydraulic control system of the forklift truck, the proportional valve 18 is arranged on the first oil return branch 10, so that the accurate control of the descending speed of the fork can be conveniently and quickly realized, the fork can descend in a creeping manner, the hydraulic impact caused by the excessively high descending speed of the goods is reduced, the shaking of a truck body caused by the hydraulic impact is avoided, and the descending stability of the goods and the use safety of the hydraulic system are greatly improved; meanwhile, the forklift is more convenient to carry out height-fixing taking and placing operations.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.