CN210117217U - Forklift and forklift gantry lifting hydraulic system - Google Patents
Forklift and forklift gantry lifting hydraulic system Download PDFInfo
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- CN210117217U CN210117217U CN201920655143.4U CN201920655143U CN210117217U CN 210117217 U CN210117217 U CN 210117217U CN 201920655143 U CN201920655143 U CN 201920655143U CN 210117217 U CN210117217 U CN 210117217U
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Abstract
The utility model discloses a fork truck portal lift hydraulic system, including working oil circuit, main oil return way, at least one play to rise hydro-cylinder and switching-over valve, the rodless chamber that plays to rise the hydro-cylinder links to each other with the working oil circuit, plays to rise the pole chamber of hydro-cylinder and links to each other so that have to form between pole chamber and the coupling and be used for guiding fluid backward flow to the low pressure oil return way that has the pole chamber, switching-over valve selectivity intercommunication working oil circuit and coupling through coupling and main oil return way. When a heavy object presses a piston rod of the lifting oil cylinder, the piston rod pushes oil in the rodless cavity to flow into the working oil way, the reversing valve can be communicated with the working oil way and the pipe joint, and the oil flowing out of the working oil way flows back to the rod cavity and the main oil return way through the pipe joint respectively, so that fluid friction is formed between the piston rod and the cylinder barrel, the piston rod or the cylinder barrel is prevented from being seriously abraded, further the working failure of the lifting oil cylinder is avoided, the lifting oil cylinder can be stably stretched, and the fork works stably. The utility model discloses still disclose a fork truck that contains fork truck portal hydraulic system.
Description
Technical Field
The utility model relates to a fork truck field, in particular to fork truck portal lift hydraulic system. The utility model discloses still relate to a fork truck.
Background
The forklift realizes the carrying of heavy objects by lifting the fork, the types of the carried goods are rich, and the forklift is widely applied to the fields of logistics, manufacturing, engineering and the like, so that the optimization of the performance of the forklift is particularly necessary.
In view of the advantages of wide speed regulation range, large output power and the like of a hydraulic system, the existing forklift generally drives the gantry to lift through the hydraulic system, and then the gantry drives the fork to realize corresponding actions. Existing forklift hydraulic systems include a single-acting piston cylinder having at least one piston rod connected to the fork, the rodless chamber of which is typically connected to a working oil circuit and the rod chamber of which is connected to a gas line located above the oil tank in order to direct the air exiting the rod chamber to the air layer of the oil tank. In general, when the rodless cavity is fed with oil, the oil pushes the piston to move so as to extrude air in the rod cavity into the air delivery pipe, and the piston rod extends out to realize ascending; when a heavy object is pressed on the fork, the fork presses the piston rod down to enable the oil in the rodless cavity to flow back to the working oil way and enable the piston rod to retract to achieve descending; the above actions are repeated, so that the lifting of the fork is realized.
Therefore, the hydraulic oil-free fork can be pushed out, and in the working process of the single-action piston cylinder, the piston rod and the cylinder barrel have certain rigid friction due to the fact that the rod cavity does not contain hydraulic oil all the time, so that the piston rod is seriously abraded, and the stable work of the fork is further influenced.
SUMMERY OF THE UTILITY MODEL
In view of this, the utility model aims at providing a fork truck and fork truck portal lift hydraulic system avoids the rigidity friction, makes fork work more stable.
The specific scheme is as follows:
the utility model provides a fork truck portal lift hydraulic system, rise hydro-cylinder and switching-over valve including working oil circuit, main oil return way, at least one, rise the no pole chamber of hydro-cylinder with the working oil circuit links to each other, rise the pole chamber of hydro-cylinder through the coupling with the main oil return way links to each other so that there is the pole chamber with form between the coupling and be used for guiding fluid backward flow extremely there is the low pressure oil return way in pole chamber, switching-over valve selectivity intercommunication the working oil circuit with the coupling.
Preferably, the lifting oil cylinder comprises a rear left piston cylinder, a rear right piston cylinder and a front middle piston cylinder, a rodless cavity of the rear left piston cylinder, a rodless cavity of the rear right piston cylinder and a cavity of the front middle piston cylinder are respectively connected with the working oil way, and a rod cavity of the rear left piston cylinder and a rod cavity of the rear right piston cylinder are respectively connected with the low-pressure oil return way.
Preferably, the air filter further comprises an oil tank connected with the main oil return path, a main oil inlet path connected with the oil tank, and an air filter arranged on the oil tank to filter air exhausted from the oil tank.
Preferably, when the reversing valve is in the first position, the main oil inlet path is communicated with the main oil return path through the pipe joint, and oil flowing out of the main oil inlet path flows into the main oil return path through the reversing valve; when the reversing valve is in the second position, the main oil inlet passage is communicated with the working oil passage, and oil flowing out of the main oil inlet passage flows into the working oil passage through the reversing valve until the oil flows into the main oil return passage through the low-pressure oil return passage; when the reversing valve is in the third position, the working oil way is communicated with the pipe joint, and oil flowing out of the lifting oil cylinder respectively flows back to the low-pressure oil return way and the main oil return way through the reversing valve.
Preferably, the reversing valve is a multi-way reversing valve with at least one valve body, the working oil path is connected with any one of the valve bodies, and a sequence valve for controlling at least one valve body to act sequentially is arranged between an oil outlet of any one of the valve bodies and the pipe joint.
Preferably, the hydraulic control system further comprises a speed limiting valve arranged in the working oil path to limit the oil flow rate of the working oil path.
Preferably, the anti-explosion device further comprises at least one anti-explosion valve which is arranged at the oil inlet of the lifting oil cylinder in a one-to-one correspondence mode.
Preferably, the safety overflow valve further comprises a safety overflow valve, wherein an oil inlet is connected with the main oil inlet path, and an oil outlet is connected with the pipe joint.
Preferably, the oil filter is arranged on the main oil return path, is connected with the oil tank and is used for filtering oil.
The utility model also provides a forklift, including the frame body and as above arbitrary fork truck portal lift hydraulic system, fork truck portal lift hydraulic system install in the frame body.
Compared with the prior art, the utility model provides a fork truck portal lift hydraulic system includes working oil circuit, main oil return way and at least one plays to rise the hydro-cylinder. In view of the fact that a rodless cavity of the lifting oil cylinder is connected with a working oil way and a rod cavity of the lifting oil cylinder is connected with a main oil return way, when a heavy object presses a piston rod of the lifting oil cylinder, the piston rod pushes oil in the rodless cavity to flow into the working oil way, a reversing valve can be communicated with the working oil way and a pipe joint, and the oil flowing out of the working oil way flows back to the rod cavity and the main oil return way through the pipe joint respectively, so that fluid friction is formed between the piston rod and a cylinder barrel, the piston rod or the cylinder barrel is prevented from being seriously abraded, the lifting oil cylinder is prevented from working failure, correspondingly, the lifting oil cylinder can stably achieve stretching, and.
The forklift comprising the forklift gantry hydraulic system has the same beneficial effects.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a schematic diagram of a forklift mast hydraulic system with two lifting cylinders according to an embodiment of the present invention;
FIG. 2 is a partial schematic diagram of a forklift mast hydraulic system having three lift cylinders;
fig. 3 is a view showing a state of connection using a pipe joint having three connection ports;
fig. 4 is a view of a forklift structure including a forklift gantry hydraulic system according to an embodiment of the present invention.
The reference numbers are as follows:
the device comprises a filter 1, a hydraulic pump 2, a main oil inlet path 3, a multi-path reversing valve 4, a working oil path 5, a speed-limiting valve 6, an explosion-proof valve 7, a lifting oil cylinder 8, a low-pressure oil return path 9, a pipe joint 10, a main oil return path 11, an oil tank 12, an oil return oil filter 13, an air filter 14 and a frame body 15;
a left piston cylinder 811 and a right piston cylinder 812;
a rear left piston cylinder 821, a rear right piston cylinder 822 and a front middle plunger cylinder 823.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
In order to make the technical field better understand the solution of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings and specific embodiments.
The embodiment of the utility model discloses fork truck portal lift hydraulic system, it needs to explain here, this hydraulic system both can be used for combustion fork truck, also can be used to electric fork truck.
In this particular embodiment, the preferred forklift mast lift hydraulic system is applied to an electric forklift.
The forklift mast lifting hydraulic system comprises a working oil way 5 and a main oil return way 11, wherein the main oil return way 11 is connected with an oil tank 12.
The utility model discloses still include at least one and play to rise hydro-cylinder 8, wherein, at least one plays to rise hydro-cylinder 8 can be the single piston cylinder that is used for driving two sections portal frame and goes up and down, also can be two piston cylinders about being used for driving two sections portal frame and going up and down, can also be two piston cylinders and preceding middle plunger cylinder about being used for driving the three section full free portal frame and going up and down, of course, can also be two piston cylinders and two middle plunger cylinders about being used for driving the three section full free portal frame and going up and down, perhaps be greater than four pneumatic cylinders.
A rodless cavity of the lifting oil cylinder 8 is connected with the working oil way 5, and a rod cavity of the lifting oil cylinder 8 is connected with a main oil return way 11 through a pipe joint 10, so that a low-pressure oil return way 9 for guiding oil to flow back to the rod cavity is formed between the rod cavity and the pipe joint 10.
The utility model discloses still including the switching-over valve that can selective intercommunication working oil circuit and coupling 10.
Referring to fig. 1, fig. 1 is a schematic diagram of a forklift mast hydraulic system with two lifting cylinders according to an embodiment of the present invention.
When the lifting oil cylinder 8 consists of a left piston cylinder 811 and a right piston cylinder 812, the lifting oil cylinder 8 specifically comprises a left piston cylinder 811 and a right piston cylinder 812, wherein a rodless cavity of the left piston cylinder 811 and a rodless cavity of the right piston cylinder 812 are respectively connected with the working oil path 5, and a rod cavity of the left piston cylinder 811 and a rod cavity of the right piston cylinder 812 are respectively connected with the low-pressure oil return path 9. When a heavy object is pressed down, oil in the rodless cavity of the left piston cylinder 811 and the rodless cavity of the right piston cylinder 812 enters the working oil way 5, flows out of the reversing valve and then flows to the low-pressure oil return way 9 and the main oil return way 11 through the pipe joint 10 respectively, and then flows into the rod cavity of the left piston cylinder 811 and the rod cavity of the right piston cylinder 812 through the low-pressure oil return way 9 respectively, so that fluid friction is formed between the piston rod of the left piston cylinder 811 and the cylinder barrel and between the piston rod of the right piston cylinder 812 and the cylinder barrel.
Referring to fig. 2, fig. 2 is a partial schematic diagram of a forklift mast hydraulic system having three lift cylinders.
When the lifting cylinder 8 is composed of a left piston cylinder, a right piston cylinder and a front middle piston cylinder, the lifting cylinder 8 specifically includes a rear left piston cylinder 821, a rear right piston cylinder 822 and a front middle piston cylinder 823, wherein a rod-free cavity of the rear left piston cylinder 821, a rod-free cavity of the rear right piston cylinder 822 and a cavity of the front middle piston cylinder 823 are respectively connected with the working oil path 5, and a rod-containing cavity of the rear left piston cylinder 821 and a rod-containing cavity of the rear right piston cylinder 822 are respectively connected with the low-pressure oil return path 9. When the heavy object is pressed down, the piston on the piston rod pushes the oil in the rodless cavity to respectively flow into the working oil way 5, sequentially flows through the reversing valve and the pipe joint 10, then respectively flows into the low-pressure oil return path 9 and the main oil return path 11, and respectively flows into the rod cavity of the rear left piston cylinder 821 and the rod cavity of the rear right piston cylinder 822 through the low-pressure oil return path 9, so that fluid friction is formed inside the rear left piston cylinder 821 and inside the rear right piston cylinder 822.
Similarly, when the number of the lifting cylinders 8 is more than or equal to four, fluid friction can still be formed inside the related cylinders.
In conclusion, the fluid friction formed inside the piston cylinder can avoid serious abrasion between the piston rod and the cylinder barrel due to rigid friction, avoid the working failure of the lifting oil cylinder 8, and is beneficial to prolonging the service life of the lifting oil cylinder 8 so as to ensure that the pallet fork continuously and effectively works; meanwhile, the lifting oil cylinder 8 can stably realize extension, so that the fork works more stably.
In addition, because the rod cavity of the rear left piston cylinder 821 and the rod cavity of the rear right piston cylinder 822 are respectively connected with the low-pressure oil return path 9, the working pressure of the rod-free cavity of the rear left piston cylinder 821 and the rod-free cavity of the rear right piston cylinder 822 is relatively increased, the rod-free cavity of the rear left piston cylinder 821, the rod-free cavity of the rear right piston cylinder 822 and the cavity of the front middle plunger 823 are respectively connected with the working oil path 5, so that the pressure difference between the front middle plunger 823 and the rear left piston cylinder 821 and between the front middle plunger 823 and the rear right piston cylinder 822 is increased, the oil flowing out of the working oil path 5 is prevented from firstly flowing into the front middle plunger 823, the disordered expansion phenomenon of the rear left piston cylinder 821, the rear right piston cylinder 822 and the front middle plunger 823 is prevented, the stable lifting of the portal frame is ensured, and the fork is further ensured to work more stably.
The utility model discloses still include the oil tank 12 that links to each other with main oil return way 11 and the main oil inlet 3 that links to each other with oil tank 12 to and locate the air cleaner 14 of oil tank 12 top, so that the exhaust air of filtered oil tank 12. Wherein, the main oil inlet path 3 is provided with a hydraulic pump 2 for boosting power and a filter 1 for filtering oil. The low-pressure oil return path 9 is used for replacing the existing gas transmission pipeline, so that oil flows into the rod cavity of the lifting oil cylinder 8, the air exhausted by the rod cavity of the lifting oil cylinder 8 is prevented from being filtered by the air filter 14 excessively or excessively fast, the risk of oil overflow of the air filter 14 is reduced, the air filter 14 continuously and reliably filters air, and the working reliability is good.
Referring to fig. 3, fig. 3 is a connection state diagram using a pipe joint having three connection ports.
For realizing the lifting function, the utility model discloses still include the switching-over valve, the preferred tribit six-way switching-over valve that is of switching-over valve body. An oil inlet of the reversing valve is connected with the main oil inlet path 3. The oil return port of the reversing valve is connected with a pipe joint 10, so that the oil return port of the reversing valve is respectively communicated with a low-pressure oil return path 9 and a main oil return path 11. The reversing valve is provided with a first oil outlet and a second oil outlet, wherein the first oil outlet is connected with the working oil way 5, and the second oil outlet is connected with the pipe joint 10.
When the reversing valve is in the first position, namely in the middle position, the main oil inlet path 3 is communicated with the main oil return path 11 through the pipe joint 10, and oil flowing out of the main oil inlet path 3 flows into the main oil return path 11 through the reversing valve, so that no-load unloading is realized.
When the reversing valve is in a second position, namely a lower position, the main oil inlet path 3 is communicated with the working oil path 5 through the one-way valve, oil flowing out of the main oil inlet path flows into the working oil path 5 through the reversing valve, oil enters the rodless cavity, and the piston rod extends outwards to realize rising; meanwhile, oil in the rod cavity flows into the main oil return path 11 through the low-pressure oil return path 9.
It should be noted that, in the initial state, the rod chamber is in an oil-free state, that is, the rod chamber is filled with air, when the piston rod extends outward, the air in the rod chamber is squeezed into the air layer of the oil tank 12, and is filtered by the air filter 14 and then discharged; and when the piston rod retracts, oil in the rodless cavity flows out of the working oil way 5 and the reversing valve in sequence and then flows into the rod cavity through the low-pressure oil return way 9, so that the rod cavity can keep an oil state. After the piston rod diameter is stretched once, the rod cavity can always keep an oil state in the subsequent working process, so that fluid friction is realized inside the piston cylinder.
When the reversing valve is in a third position, namely an upper position, working oil is communicated with the main oil return path 11, when a heavy object presses the piston rod, the oil in the oil tank 12 sequentially flows into the rod cavity through the reversing valve, the main oil return path 11 and the low-pressure oil return path 9, the piston rod contracts simultaneously to realize descending, and the oil in the rodless cavity is squeezed into the working oil path 5 by the piston rod and then flows into the main oil return path 11.
What needs to be supplemented here is that a check valve is arranged between the oil inlet of the reversing valve and the main oil inlet 3, so that oil can flow into the oil inlet of the reversing valve from the main oil inlet 3 in a one-way manner, the oil in the reversing valve is prevented from flowing backwards in the working process, and the safety and reliability of the hydraulic system are ensured. In addition, the pressure of the low-pressure oil return path 9 is lower than the maximum back pressure allowed by the reversing valve, so that the lifting oil cylinders 8 can be ensured to run safely and reliably.
Preferably, the reversing valve is a multi-way reversing valve 4 with at least one valve body, and the working oil circuit 5 is connected with any valve body so as to realize the lifting of the gantry. Wherein, the oil inlet of all valve bodies links to each other, and the oil return opening of all valve bodies all links to each other with main oil return way 11, and multichannel reversing valve 4 makes the valve body can also realize other functions except can realizing portal raising and lowering functions, and occupation space is little, simple to operate. In addition, a sequence valve 41 is arranged between the oil outlet of any valve body and the pipe joint 10 so as to control all the valve bodies to act orderly and prevent the oil circuit from being disordered. Specifically, the multiple change direction valve 4 is a spool valve, and the working oil path 5 is connected to a valve body of which the spool valve function is a.
Preferably, in this specific embodiment, the multi-way directional control valve 4 includes four valve bodies, one of the valve bodies is used for realizing the lifting of the gantry, and the other three valve bodies have pending functions. Specifically, the sequence valves 41 include two sequence valves 41, the two sequence valves 41 are respectively connected to two valve bodies with undetermined functions, and the two sequence valves 41 have the same structure and are both composed of an overflow valve and a check valve which are connected in parallel.
It should be noted that the pipe joint 10 described herein may be a three-way joint or a four-way joint. When the pipe joint 10 is a three-way joint, three interfaces of the pipe joint 10 are respectively connected with the low-pressure oil return path 9, the main oil return path 11 and a second oil outlet of the reversing valve; when the pipe joint 10 is a four-way joint, two of the four interfaces are respectively connected with two low-pressure oil return paths 9 which are connected in parallel, the two low-pressure oil return paths 9 are respectively connected with rod cavities of two lifting oil cylinders 8, and the other two interfaces are respectively connected with a main oil return path 11 and a second oil outlet of a reversing valve. Of course, the type of the pipe joint 10 is not limited thereto, and may be specifically set depending on the number of piston cylinders.
For controlling the lifting speed, the utility model discloses still including the speed limit valve 6 of locating working oil circuit 5, through the maximum velocity of flow or the minimum velocity of flow of injecing working oil circuit 5 to the fluid velocity of flow of injecing working oil circuit 5, and then guarantee to rise 8 reliable works effectively of hydro-cylinder. Specifically, the governor valve 6 is formed by combining a constant-differential pressure reducing valve and a throttle valve which are communicated with each other.
For promoting the security, the utility model discloses still include at least one explosion-proof valve 7, every oil inlet that plays to rise hydro-cylinder 8 is located respectively correspondingly to a plurality of explosion-proof valves 7 to it is flexible to guarantee every to play to rise hydro-cylinder 8 safe and reliable ground. Preferably, the oil inlet of each explosion-proof valve 7 is connected with the oil outlet of the speed-limiting valve 6, and the oil outlet of each explosion-proof valve 7 is connected with the oil inlet of the corresponding lifting oil cylinder 8. The structure of the explosion-proof valve 7 can be referred to the prior art in particular.
For further promoting the security, the utility model discloses still including the safety overflow valve 42 between the oil inlet of locating the switching-over valve and the oil return opening, the oil inlet of safety overflow valve 42 links to each other with main oil inlet 3, and the oil-out of safety overflow valve 42 links to each other with coupling 10, and when pressure between the oil inlet of switching-over valve and the oil return opening was higher than the settlement pressure of safety overflow valve 42, safety overflow valve 42 opened, realized the off-load.
The utility model discloses still including locating the main oil return way 11 and the oil return oil filter 13 that links to each other with oil tank 12 to filter fluid, prevent to pollute fluid.
Use electric fork truck as example, the utility model provides a fork truck portal lift hydraulic system's theory of operation as follows:
when the reversing valve is in the middle position, the electric forklift motor does not work, the hydraulic pump 2 stops rotating, and the main oil inlet path 3 has no oil;
when the reversing valve is in the lower position, the hydraulic pump 2 is started, the filtered oil flows into the main oil inlet path 3 through the hydraulic pump 2, the oil flowing out of the main oil inlet path 3 flows into the working oil path 5 through the reversing valve, then flows into the rodless cavity of the lifting oil cylinder 8 through the speed-limiting valve 6 and the explosion-proof valve 7 in sequence, and the piston rod extends outwards to realize lifting;
the piston rod extrudes the air in the rod cavity into the low-pressure oil return path 9, the air partially flows into the main oil return path 11 through the pipe joint 10, then flows into the air layer of the oil tank 12 through the main oil return path 11 and is discharged through the air filter 14;
when the lifting oil cylinder 8 is pressed down by a heavy object, the hydraulic pump 2 stops rotating, goods push a piston rod of the lifting oil cylinder 8 to move downwards under the action of gravity, oil in a rodless cavity is pushed into a working oil way 5, and then the oil flows back into a reversing valve through an explosion-proof valve 7 and a speed-limiting valve 6 in sequence; at the moment, the reversing valve is in an upper position, the oil liquid flowing out through the reversing valve flows back to the pipe joint 10, one part of the oil liquid flows into the low-pressure oil return path 9 and discharges the air in the low-pressure oil return path 9, and the other part of the oil liquid flows back to the oil tank 12 through the main loop;
the reversing valve is shifted to the lower position again, the hydraulic pump 2 is started, the filtered oil flows into the main oil inlet path 3 through the hydraulic pump 2, the oil flowing out of the main oil inlet path 3 flows into the working oil path 5 through the reversing valve, then flows into the rodless cavity of the lifting oil cylinder 8 through the speed limiting valve 6 and the explosion-proof valve 7 in sequence, the piston rod pushes the oil in the rod cavity to flow into the low-pressure oil return path 9, and then flows back into the oil tank 12 through the joint 10 and the main oil return path 11 in sequence;
the lifting oil cylinder 8 is pressed down again, the hydraulic pump 2 stops rotating, the goods push the piston rod of the lifting oil cylinder 8 to move down, the oil liquid in the rodless cavity is pushed into the working oil way 5, and then flows back to the reversing valve through the explosion-proof valve 7 and the speed limiting valve 6 in sequence; the reversing valve is shifted to be in an upper position, oil flowing out through the reversing valve flows back to the pipe joint 10, one part of the oil flows into the rod cavity through the low-pressure oil return path 9, and the other part of the oil flows back to the oil tank 12 through the main loop;
the lifting of the lifting oil cylinder 8 is repeatedly realized through the circulation.
Use diesel fork truck as the example, the utility model provides a fork truck portal lift hydraulic system's theory of operation as follows:
when the reversing valve is in the middle position, the diesel fork-lift truck runs the hydraulic pump 2 at idle speed, the filtered oil flows into the main oil inlet passage 3 through the hydraulic pump 2 and then flows into the pipe joint 10 through the reversing valve, one part of the oil flows into the rod cavity through the low-pressure oil return passage 9, and the other part of the oil flows into the oil tank 12;
the oil liquid flowing into the rod cavity extrudes the air in the rod cavity into the low-pressure oil return path 9, flows into an air layer of an oil tank 12 through a pipe joint 10 and a main oil return path 11 in sequence, and is filtered by an air filter 14 and then discharged;
when the reversing valve is in the lower position, the hydraulic pump 2 is accelerated, the filtered oil flows into the main oil inlet path 3 through the hydraulic pump 2, the oil flowing out of the main oil inlet path 3 flows into the working oil path 5 through the reversing valve, then flows into a rodless cavity of the lifting oil cylinder 8 through the speed-limiting valve 6 and the explosion-proof valve 7 in sequence, and the piston rod extends outwards to realize lifting; the piston rod pushes the oil in the rod cavity into the low-pressure oil return path 9, and then the oil flows back to the oil tank 12 through the pipe joint 10 and the main oil return path 11 in sequence;
when a heavy object presses the lifting oil cylinder 8 downwards, the hydraulic pump 2 runs at an idle speed, goods push a piston rod of the lifting oil cylinder 8 downwards under the action of gravity, oil in a rodless cavity is pushed into the working oil way 5, and then the oil flows back into the reversing valve through the explosion-proof valve 7 and the speed-limiting valve 6 in sequence; at the moment, the reversing valve is positioned at an upper position, the oil liquid flowing out through the reversing valve flows back to the pipe joint 10, one part of the oil liquid flows into the rod cavity through the low-pressure oil return path 9, and the other part of the oil liquid flows back to the oil tank 12 through the main loop;
the lifting of the lifting oil cylinder 8 is repeatedly realized through the circulation.
Referring to fig. 4, fig. 4 is a structural diagram of a forklift including a hydraulic system of a forklift gantry according to an embodiment of the present invention.
The utility model also provides a fork truck, including frame body 15 and above-mentioned fork truck portal lift hydraulic system, fork truck portal lift hydraulic system installs in frame body 15. The frame body 15 comprises a portal frame and a frame, the lifting oil cylinder 8 is mounted on the portal frame, and the portal frame is mounted in the frame, so that the portal frame can be lifted stably by the aid of the lifting hydraulic system of the forklift portal frame, and the natural fork works stably.
The forklift and the forklift gantry lifting hydraulic system provided by the utility model are introduced in detail, and the principle and the implementation mode of the utility model are explained by applying specific examples, and the explanation of the above embodiments is only used for helping to understand the method and the core idea of the utility model; meanwhile, for the general technical personnel in the field, according to the idea of the present invention, there are changes in the specific implementation and application scope, to sum up, the content of the present specification should not be understood as the limitation of the present invention.
Claims (10)
1. The utility model provides a fork truck portal lift hydraulic system, includes working oil circuit (5) and main oil return way (11), its characterized in that still includes at least one and rises hydro-cylinder (8) and switching-over valve, rise the rodless chamber of hydro-cylinder (8) with working oil circuit (5) link to each other, rise the pole chamber of hydro-cylinder (8) pass through coupling (10) with main oil return way (11) link to each other so that there is the pole chamber with form between coupling (10) and be used for guiding fluid to flow back to there is the low pressure oil return way (9) in pole chamber, the switching-over valve selectivity intercommunication working oil circuit (5) with coupling (10).
2. The forklift mast lifting hydraulic system according to claim 1, characterized in that the lifting cylinder (8) comprises a rear left piston cylinder (821), a rear right piston cylinder (822) and a front middle piston cylinder (823), a rodless cavity of the rear left piston cylinder (821), a rodless cavity of the rear right piston cylinder (822) and a cavity of the front middle piston cylinder (823) are respectively connected with the working oil circuit (5), and a rod cavity of the rear left piston cylinder (821) and a rod cavity of the rear right piston cylinder (822) are respectively connected with the low-pressure oil return circuit (9).
3. The forklift mast lift hydraulic system according to claim 1, further comprising an oil tank (12) connected to said main return line (11), a main oil inlet line (3) connected to said oil tank (12), and an air filter (14) provided in said oil tank (12) for filtering air discharged from said oil tank (12).
4. The forklift mast lift hydraulic system according to claim 3, characterized in that when the reversing valve is in the first position, the main oil feed (3) is in communication with the main oil return (11) through the pipe connection (10), the oil flowing out of the main oil feed (3) flowing into the main oil return (11) through the reversing valve; when the reversing valve is in a second position, the main oil inlet path (3) is communicated with the working oil path (5), and oil flowing out of the main oil inlet path (3) flows into the working oil path (5) through the reversing valve until the oil flows into the main oil return path (11) through the low-pressure oil return path (9); when the reversing valve is in a third position, the working oil way (5) is communicated with the pipe joint (10), and oil flowing out of the lifting oil cylinder (8) respectively flows back to the low-pressure oil return way (9) and the main oil return way (11) through the reversing valve.
5. The forklift mast lift hydraulic system according to claim 4, characterized in that the directional valve is a multi-way directional valve (4) having at least one valve body, the working oil circuit (5) is connected to any one of the valve bodies, and a sequence valve (41) for controlling the sequential action of at least one of the valve bodies is arranged between the oil outlet of any one of the valve bodies and the pipe joint (10).
6. The forklift mast lift hydraulic system according to any one of claims 1 to 5, further comprising a speed limit valve (6) provided to the working oil circuit (5) to limit the flow rate of oil of the working oil circuit (5).
7. The hydraulic lift system of a forklift mast as defined in claim 6, further comprising at least one explosion-proof valve (7) disposed in one-to-one correspondence at the inlet of the lift cylinder (8).
8. The forklift mast lift hydraulic system according to claim 4, characterized in that it further comprises a safety relief valve (42) having an oil inlet connected to said main oil inlet line (3) and an oil outlet connected to said pipe joint (10).
9. The forklift mast lift hydraulic system of claim 4, further comprising a return oil filter (13) disposed in the main return (11) and connected to the oil tank (12) for filtering oil.
10. A forklift truck, characterized by comprising a frame body (15) and the forklift mast lift hydraulic system of any one of claims 1 to 9 mounted to the frame body (15).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920655143.4U CN210117217U (en) | 2019-05-08 | 2019-05-08 | Forklift and forklift gantry lifting hydraulic system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920655143.4U CN210117217U (en) | 2019-05-08 | 2019-05-08 | Forklift and forklift gantry lifting hydraulic system |
Publications (1)
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110228774A (en) * | 2019-05-08 | 2019-09-13 | 杭叉集团股份有限公司 | A kind of fork truck and forklift door frame hydraulic system for lifting |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110228774A (en) * | 2019-05-08 | 2019-09-13 | 杭叉集团股份有限公司 | A kind of fork truck and forklift door frame hydraulic system for lifting |
| CN110228774B (en) * | 2019-05-08 | 2024-04-09 | 杭叉集团股份有限公司 | Fork truck and fork truck portal hydraulic system that goes up and down |
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