Lifting oil cylinder with buffer structure, forklift and working method of forklift

Abstract

The lifting oil cylinder with the buffering structure comprises a piston rod, a piston, a cylinder body and an oil pipe, one end of the piston rod is connected with the piston, the other end of the piston rod can stretch out of the cylinder body, and the interior of the cylinder body is divided into a rod cavity and a rodless cavity through the piston; the piston rod is of a hollow structure, the oil pipe extends into the piston rod and forms an oil chamber with the inner wall of the piston rod, and a throttling hole is formed in the wall face of the piston rod. The buffering structure on the lifting oil cylinder further comprises a buffering sleeve which is installed in the cylinder body, and the inner diameter of the buffering sleeve is slightly larger than the outer diameter of the piston rod. The lifting oil cylinder is ingenious in structure, the upper buffering structure is additionally arranged, so that the portal frame can be stably and slowly lifted to the top, the influence of violent impact on goods placed on a pallet fork is avoided, and the use experience of a user is enhanced. The forklift and the working method thereof have the advantages that the stability of the goods can be guaranteed, and therefore damage to the goods is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of forklifts, and in particular to a lifting oil cylinder with a buffer structure, a forklift and a working method of the forklift. Background Art

[0002] A forklift is an industrial handling vehicle primarily used for loading, unloading, stacking, and short-distance transport of goods. It is widely used in ports, stations, airports, freight yards, factory workshops, warehouses, distribution centers, and distribution centers. A forklift's structure primarily consists of a power unit, chassis, working mechanism, hydraulic system, and electrical equipment. Common forklift types include internal combustion forklifts (fueled by gasoline, diesel, or liquefied petroleum gas) and electric forklifts (powered by batteries).

[0003] Lifting a forklift mast primarily relies on a hydraulic system. The core component of this system is the hydraulic pump, which is driven by an engine or electric motor. When the operator operates the handle, the hydraulic pump activates, pumping hydraulic oil from the tank and delivering it through a pipe to the lift cylinder. The lift cylinder is a key component that converts hydraulic energy into mechanical energy. In a forklift mast system, the lift cylinder is typically mounted at the bottom of the mast. When hydraulic oil enters the lift cylinder, it pushes the piston upward, which, through mechanical structures such as connecting rods, drives the mast and forks upward.

[0004] like Figure 4 As shown, the existing oil cylinder 1' used in the prior art will cause a high-speed collision between the existing oil cylinder piston 1-1' and the top of the existing guide sleeve 1-2' when it is lifted to the limit position, thereby causing the mast and the body to vibrate violently, generating noise and shortening the service life of the parts on the forklift, increasing the cost of use, affecting the user's experience, and being detrimental to the promotion and application of the above-mentioned forklift in the market. Summary of the Invention

[0005] In order to overcome the defects in the above-mentioned prior art, the first invention purpose of the present invention is to provide a lifting cylinder, which, by adding an upper buffer structure, allows the mast to be lifted to the top smoothly and gently, avoiding violent impacts on the goods placed on the forks, enhancing the user experience, and facilitating the promotion and application of the above-mentioned upper buffer structure of the lifting cylinder for forklifts in the field of forklift technology. The second invention purpose of the present invention is to provide a forklift, which, by applying the above-mentioned lifting cylinder, also has the advantage of being able to ensure the stability of the goods, thereby reducing damage to the goods. The third invention purpose of the present invention is to provide a working method for a forklift, which, by applying the above-mentioned lifting cylinder, also has the advantage of being able to ensure the stability of the goods, thereby reducing damage to the goods.

[0006] The above-mentioned lifting cylinder, the above-mentioned forklift and the above-mentioned working method of the forklift are technically related to each other and belong to the same inventive concept.

[0007] In order to achieve the above-mentioned first invention purpose, the present invention adopts the following technical solutions: a lifting cylinder with a buffer structure, comprising a piston rod, a piston, a cylinder body and an oil pipe, one end of the piston rod is connected to the piston, and the other end of the piston rod can extend out of the cylinder body, and the interior of the cylinder body is divided into a rod cavity and a rodless cavity by the piston; the piston rod is a hollow structure, the oil pipe extends into the piston rod and forms an oil chamber between the inner wall of the piston rod, and a throttling hole is opened on the wall surface of the piston rod; the buffer structure on the lifting cylinder also includes a buffer sleeve, which is installed in the cylinder body and whose inner diameter is slightly larger than the outer diameter of the piston rod.

[0008] As a preferred solution of the present invention, the buffer sleeve is arranged near the top opening of the cylinder body.

[0009] As a preferred solution of the present invention, the inner diameter of the buffer sleeve is gradually increased from top to bottom.

[0010] As a preferred solution of the present invention, a guide sleeve is further provided. The guide sleeve is arranged near the opening of the cylinder body and is located above the buffer sleeve.

[0011] As a preferred solution of the present invention, a dust ring is provided at the opening of the cylinder body.

[0012] Compared with the prior art, the beneficial effects of the present invention are as follows: the lifting oil cylinder with a buffer structure in the present invention is ingenious in structure. By arranging a piston rod, a piston, a cylinder body, an oil pipe and a buffer sleeve, one end of the piston rod is connected to the piston, and the other end can extend out of the cylinder body, and the interior of the cylinder body is divided into a rod cavity and a rodless cavity by the piston, the oil pipe extends into the interior of the hollow piston rod and forms an oil chamber between the oil pipe and the inner wall of the piston rod, and a throttle hole is provided on the wall surface of the piston rod, the buffer sleeve is installed in the cylinder body, and the inner diameter of the buffer sleeve is slightly larger than the outer diameter of the piston rod. When oil enters the rodless cavity of the lifting oil cylinder, the piston rod extends outward, and the mast of the forklift starts to lift from the lowest position; When the oil storage part of the cylinder enters the buffer sleeve, the hydraulic oil flows into the oil chamber through the gap between the buffer sleeve and the piston rod through the throttle hole. The hydraulic pressure generates back pressure due to the squeezing of the hydraulic oil. The force generated by the back pressure causes the control valve at the bottom of the lifting cylinder to overflow. The flow rate supplied to the lifting cylinder by the hydraulic system becomes smaller, and the extension speed of the cylinder slows down, thereby reducing the probability of high-speed collision between the piston and the top of the cylinder body, reducing the frequency of severe vibration of the mast and the body, reducing noise, and extending the service life of parts on the forklift, reducing the cost of use, and enhancing the user experience, which is conducive to the promotion and application of the above-mentioned lifting cylinder with a buffer structure in the field of forklift technology.

[0013] In order to achieve the above-mentioned second invention purpose, the present invention adopts the following technical solution: a forklift, using the above-mentioned lifting cylinder with a buffer structure; there are two lifting cylinders, and an oil port one is added to the rod cavity of each of the two lifting cylinders, and the two oil ports one are connected by a pipeline.

[0014] As a preferred solution of the present invention, the pipeline is a rubber hose.

[0015] As a preferred solution of the present invention, the two oil ports are arranged at the same height.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: a forklift in the present invention, by applying the above-mentioned lifting cylinder with a buffer structure, and there are two lifting cylinders, and an oil port one is added to the rod cavity of each lifting cylinder, and the two oil ports one are connected by a pipeline, which can further ensure the stability of the forklift during use, thereby reducing damage to the cargo.

[0017] In order to achieve the above-mentioned third invention purpose, the present invention adopts the following technical solutions: a working method of a forklift, applying the above-mentioned lifting cylinder with a buffer structure; when oil enters the rodless chamber of the lifting cylinder, the piston rod extends outward, and the mast of the forklift starts to lift from the lowest position; when the oil storage part of the cylinder enters the buffer sleeve, the hydraulic oil flows into the oil chamber through the gap between the buffer sleeve and the piston rod through the throttle hole, and the hydraulic pressure generates back pressure due to the squeezing of the hydraulic oil. The force generated by the back pressure causes the control valve located at the bottom of the lifting cylinder to overflow, and the flow rate supplied to the lifting cylinder by the hydraulic system becomes smaller, and the extension speed of the cylinder slows down.

[0018] Compared with the prior art, the beneficial effect of the present invention is that the working method of a forklift in the present invention, by being applied to the above-mentioned forklift, also has the advantage of ensuring the stability of the cargo, thereby reducing damage to the cargo. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a structural diagram of a lifting oil cylinder with a buffer structure according to an embodiment of the present invention; Figure 2 This is a schematic diagram of a state in which a lifting cylinder with a buffer structure is pre-filled with hydraulic oil according to an embodiment of the present invention; Figure 3 Schematic diagram of the oil circuit connection of a lifting oil cylinder with a buffer structure in an embodiment of the present invention; Figure 4 This is a schematic diagram of the oil circuit connection of a lifting cylinder without a buffer function in the prior art.

[0020] Figure numerals: 1, piston rod; 2, dust ring; 3, retaining ring 1; 4, sealing ring 1; 5, sealing ring 2; 6, guide sleeve; 7, sealing ring 3; 8, buffer sleeve; 9, retaining ring 2; 10, sealing ring 4; 11, cylinder body; 12, oil pipe; 13, piston; 14, one-way valve; 15, sealing ring 5; 16, gasket; 17, retaining ring 3; 18, sealing ring 6; 20, support ring; 21, oil port 2; 23, throttle hole; 24, oil chamber; 25, control valve; 26, lifting cylinder; 27, hydraulic oil; 28, oil port 1; 29, oil tank; 1', existing oil cylinder; 1-1', existing oil cylinder piston; 1-2', existing guide sleeve. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the present invention more clearly apparent, the present invention is described below using specific embodiments shown in the accompanying drawings. However, it should be understood that these descriptions are merely illustrative and are not intended to limit the scope of the present invention. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion of the concepts of the present invention.

[0022] In the description of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the present invention.

[0023] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0024] In the prior art, Figure 4 As shown, when the existing oil cylinder 1' is lifted to the limit position, a high-speed collision occurs between the existing oil cylinder piston 1-1' and the top of the existing guide sleeve 1-2', thereby causing the mast and the body to vibrate violently, generating noise and shortening the service life of the parts on the forklift, increasing the cost of use, affecting the user's experience, and being detrimental to the promotion and application of the above-mentioned forklift in the market.

[0025] In order to solve the above technical problems, Figures 1 to 3As shown, in this embodiment, a lifting cylinder with a buffer structure is mainly composed of a piston rod 1, a piston 13, a cylinder body 11 and an oil pipe 12. One end of the above-mentioned piston rod 1 is connected to the above-mentioned piston 13, and the other end of the above-mentioned piston rod 1 can extend from the cylinder cover to the outside of the above-mentioned cylinder body 11. The interior of the above-mentioned cylinder body 11 is divided into a rod chamber and a rodless chamber by the above-mentioned piston 13. When the rodless chamber is connected to the oil source, the hydraulic system inputs hydraulic oil into the rodless chamber of the hydraulic cylinder to push the piston rod 1 to extend; when the rodless chamber is connected to the oil tank 29, the piston rod 1 is compressed back under the action of the gravity of the mast, and the oil in the hydraulic cylinder flows back to the oil tank 29. The lifting and lowering action of the forklift fork is realized through the above control. The piston rod 1 in this embodiment is a hollow structure, the oil pipe 12 extends into the piston rod 1 and forms an oil chamber 24 for storing oil between the inner wall of the piston rod 1, and a throttle hole 23 is provided on the wall of the piston rod 1. A buffer sleeve 8 is installed at a position close to the top of the cylinder body 11 and below the guide sleeve 6. The inner diameter of the buffer sleeve 8 is slightly larger than the outer diameter of the piston rod 1. When oil enters the rodless cavity of the lifting cylinder, the piston rod 1 extends outward and the mast of the forklift starts to lift; when the hydraulic oil in the oil storage part of the cylinder (i.e. the part between the cylinder body 11 and the piston rod 1) enters the buffer sleeve 8, the hydraulic oil passes through the buffer sleeve 8. The gap between the sleeve 8 and the piston rod 1 flows into the oil chamber 24 through the throttle hole 23. The hydraulic oil is squeezed to generate back pressure. The force generated by the back pressure causes the control valve 25 at the bottom of the lifting cylinder to overflow. The flow of the hydraulic system to the lifting cylinder becomes smaller, and the extension speed of the cylinder slows down, thereby avoiding high-speed collision between the piston 13 and the guide sleeve 6 inside the cylinder body 11, reducing the severe vibration of the mast and the body, reducing noise, and extending the service life of the parts on the forklift, reducing the cost of use, and enhancing the user experience. It is conducive to the promotion and application of the above-mentioned lifting cylinder with a buffer structure in the field of forklift technology.

[0026] The guide sleeve 6 is installed inside the cylinder body 11 and is arranged near the top of the cylinder body 11. Its main purpose is to guide the piston rod 1 to perform linear motion, ensure that the piston rod 1 maintains precise coaxiality during reciprocating motion, avoid offset or jamming, and thus ensure the stable operation and motion accuracy of the hydraulic cylinder. The guide sleeve 6 can also provide certain support to the piston rod 1 to prevent it from being deformed by lateral force or bending force during movement, thereby improving the load-bearing capacity and stability of the hydraulic cylinder. A dust ring 2 is installed at the opening of the guide sleeve 6, and the dust ring 2 is arranged between the cylinder body 11 and the piston rod 1 to prevent dust, sand, moisture and other impurities from entering the interior of the cylinder body 11. In order to ensure the stability of the position of the guide sleeve 6 during installation and use, a retaining ring 3 is installed inside the guide sleeve 6, and a sealing ring 4 is installed below the retaining ring 3. The sealing ring 4 and the retaining ring 3 are embedded in the groove formed on the inner wall of the guide sleeve 4.

[0027] The guide sleeve 6 and the cylinder body 11 are threadedly connected. In order to ensure the sealing of the connection between the guide sleeve 6 and the cylinder body 11 and prevent the oil from leaking out, in this embodiment, a plurality of annular grooves are formed on the outside of the guide sleeve 6, and the sealing ring 2 5 and the sealing ring 3 7 are installed in the annular grooves to increase the sealing between the guide sleeve 6 and the cylinder body 11. Similarly, in order to ensure the stability of the position of the buffer sleeve 8 during installation and use, an annular groove is provided on the outer wall of the buffer sleeve 8, and a retaining ring 2 9 and a sealing ring 4 10 are installed in the annular groove. The retaining ring 2 9 and the sealing ring 4 10 are embedded in the groove on the outer wall of the buffer sleeve 8. The arrangement of the retaining ring and the sealing ring can effectively prevent the hydraulic oil from leaking from the gap between the guide sleeve 6 and the cylinder body 11 or between the buffer sleeve 8 and the cylinder body 11.

[0028] When installed, i.e., when the buffer sleeve 8 is installed within the cylinder body 11, its inner diameter gradually increases from top to bottom, forming a trumpet-shaped opening. This design prevents a sudden increase in back pressure and a sudden decrease in cylinder speed when the piston rod 1 enters the buffer sleeve 8, which could cause mast vibration. By configuring the inner bore of the buffer sleeve 8 into a trumpet-shaped opening, the annular throttling area between the piston rod 1 and the buffer sleeve 8 decreases continuously when the piston 13 enters the buffer sleeve 8, thereby achieving stepless deceleration of the cylinder buffer, smooth and stable operation, reducing mast vibration amplitude, and thus ensuring the stability of the cargo placed on the forks.

[0029] To further prevent hydraulic oil leakage and improve the system's sealing performance and reliability, this embodiment also installs a sealing ring 15 between piston 13 and piston rod 1. The operation of the hydraulic system depends on the sealing properties of the hydraulic oil. Any leakage will cause the system pressure to drop, affecting the normal operation of the hydraulic cylinder. The installation of sealing ring 15 prevents hydraulic oil from leaking between the oil chamber and the rod chamber.

[0030] To further enhance the lifting cylinder's sealing performance and improve the overall stability and reliability of the forklift system, a sixth sealing ring 18 is installed between the piston 13 and the cylinder body 11. This prevents hydraulic oil leakage between the rod chamber and the rodless chamber. To protect the sixth sealing ring 18 from damage, three retaining rings 17 are installed above and below it. Both retaining rings 17 and the sixth sealing ring 18 are embedded in the groove on the outer wall of the piston 13 and fit tightly against the inner wall of the cylinder body 11. A support ring 20 is further provided on the outer wall of the piston 13. The central axis of the support ring 20 is located in the same straight line as the central axis of the piston 13. During the entire movement process, the support ring 20 is used to support the piston 13 to ensure that it remains stable when performing linear motion in the cylinder body 11, and prevents direct contact and friction between the piston 13 and the cylinder body 11. This design can effectively reduce direct contact between metal and metal, reduce the risk of wear, thereby ensuring the service life of the lifting cylinder and the forklift as a whole, and reducing the user's cost of use.

[0031] The bottom of the cylinder body 11 is provided with a second oil port 21, which connects to the rodless chamber of the cylinder and serves as the inlet and outlet passage for the hydraulic oil. When the hydraulic oil enters the lifting cylinder through the second oil port 21, the piston rod 1 extends, raising the mast. When the hydraulic oil exits the lifting cylinder through the second oil port 21, the piston rod 1 retracts, lowering the mast. A check valve 14 is also installed on the oil pipe 12 of the lifting cylinder's oil system to prevent backflow of the hydraulic oil.

[0032] In actual forklift operation, since the lift cylinder with a buffer structure in this embodiment uses throttling backpressure for speed regulation, the size of the throttling ring gap significantly affects the speed regulation effect. Mast frame rigidity synchronization is not sufficient to eliminate the error caused by the different throttling ring clearances of the two lift cylinders. Relying on machining to achieve the same clearance between the two cylinders is extremely difficult and would significantly increase processing costs.

[0033] In order to ensure that the two lifting cylinders 26 can move synchronously and the cost will not be greatly increased, the forklift in this embodiment uses two of the above-mentioned lifting cylinders 26, and an oil port 28 is added to the rod chamber of the two above-mentioned lifting cylinders 26 respectively. The two above-mentioned oil ports 28 are set at the same height, and the two above-mentioned oil ports 28 are connected by a hose, which ensures that the pressure of the rod chamber of the two lifting cylinders 26 is the same at any time, and is no longer affected by the processing error of the piston rod 1 and the buffer sleeve 8, thereby improving the applicability of the parts and reducing the scrap rate and debugging time of the parts.

[0034] like Figure 2 As shown, the lifting cylinder with a buffer structure in this embodiment is in a state of pre-filled hydraulic oil 27. When the piston rod 1 is fully retracted, the height of the hydraulic oil 29 must not be lower than the throttle hole 23.

[0035] A working method of a forklift in this embodiment, specifically, when oil enters the rodless chamber of the lifting cylinder 26, the above-mentioned piston rod 1 extends outward, and the mast of the forklift starts to lift from the lowest position; after the oil storage part of the cylinder enters the above-mentioned buffer sleeve 8, the hydraulic oil flows into the above-mentioned oil chamber 24 through the above-mentioned throttle hole 23 through the gap between the above-mentioned buffer sleeve 8 and the above-mentioned piston rod 1, and the hydraulic pressure generates back pressure due to the squeezing of the hydraulic oil. The force generated by the back pressure causes the control valve 25 located at the bottom of the lifting cylinder 26 to overflow, and the flow rate supplied to the lifting cylinder by the hydraulic system becomes smaller, and the extension speed of the cylinder slows down.

[0036] The present invention provides a lifting oil cylinder with a buffer structure. The lifting oil cylinder has an ingenious structure. By arranging a piston rod 1, a piston 13, a cylinder body 11, an oil pipe 12 and a buffer sleeve 8, one end of the piston rod 1 is connected to the piston 13, and the other end can extend out of the cylinder body 11, and the interior of the cylinder body 11 is divided into a rod cavity and a rodless cavity by the piston 13. The oil pipe 12 extends into the interior of the hollow structure of the piston rod 1 and forms an oil chamber 24 between the oil pipe 12 and the inner wall of the piston rod 1, and a throttle hole 23 is provided on the wall surface of the piston rod 1. The buffer sleeve 8 is installed in the cylinder body 11 and the inner diameter of the buffer sleeve 8 is slightly larger than the outer diameter of the piston rod 1. When oil enters the rodless cavity of the lifting oil cylinder, the piston rod 1 extends outward, and the mast of the forklift is raised from the lowest position. Start lifting; after the oil storage part of the cylinder enters the buffer sleeve 8, the hydraulic oil flows into the oil chamber 24 through the gap between the buffer sleeve 8 and the piston rod 1 through the throttle hole 23. The hydraulic pressure generates back pressure due to the squeezing of the hydraulic oil. The force generated by the back pressure causes the control valve at the bottom of the lifting cylinder to overflow. The flow rate supplied to the lifting cylinder by the hydraulic system becomes smaller, and the extension speed of the cylinder slows down, thereby avoiding high-speed collision between the piston 13 and the top of the cylinder body 11, reducing the frequency of severe vibration of the mast and the body, reducing noise while extending the service life of parts on the forklift, reducing the cost of use, and enhancing the user experience, which is conducive to the promotion and application of the above-mentioned lifting cylinder with a buffer structure in the field of forklift technology.

[0037] The lifting cylinder with a buffer structure in the above embodiment can be applied to, including but not limited to, forklifts. By applying the above-mentioned lifting cylinder with a buffer structure, and two lifting cylinders, and respectively providing oil ports in the rod chambers of the two lifting cylinders, and connecting the two oil ports through a pipeline, the stability of the forklift during use can be further ensured, thereby reducing the probability of damage to the goods.

[0038] The above description of the disclosed embodiments will enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is to be embodied in the widest possible manner consistent with the principles and novel features disclosed herein.

[0039] Although this document frequently uses the following terms in the figures: 1, piston rod; 2, dust seal; 3, retaining ring 1; 4, sealing ring 1; 5, sealing ring 2; 6, guide sleeve; 7, sealing ring 3; 8, buffer sleeve; 9, retaining ring 2; 10, sealing ring 4; 11, cylinder body; 12, oil pipe; 13, piston; 14, one-way valve; 15, sealing ring 5; 16, gasket; 17, retaining ring 3; 18, sealing ring 6; 20, support ring; 21, oil port 2; 23, throttle hole; 24, oil chamber; 25, control valve; 26, lifting cylinder; 27, hydraulic oil; 28, oil port 1; 29, oil tank; 1', existing oil cylinder; 1-1', existing oil cylinder piston; 1-2', existing guide sleeve, etc., the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitations is contrary to the spirit of the present invention.

Claims

1. A lifting cylinder with a buffer structure, characterized in that: The invention comprises a piston rod (1), a piston (13), a cylinder body (11) and an oil pipe (12), wherein one end of the piston rod (1) is connected to the piston (13), and the other end of the piston rod (1) can extend out of the cylinder body (11), and the interior of the cylinder body (11) is divided into a rod cavity and a rodless cavity by the piston (13); the piston rod (1) is a hollow structure, the oil pipe (12) extends into the piston rod (1) and forms an oil chamber (24) between the oil pipe (12) and the inner wall of the piston rod (1), and a throttle hole (23) is opened on the wall surface of the piston rod (1); and the invention also comprises a buffer sleeve (8), which is installed in the cylinder body (1) and has an inner diameter slightly larger than the outer diameter of the piston rod (1).

2. The lifting cylinder with a buffer structure according to claim 1, characterized in that: The buffer sleeve (8) is arranged close to the top opening of the cylinder body (11).

3. The lifting cylinder with a buffer structure according to claim 2, characterized in that: The inner diameter of the buffer sleeve (8) is gradually increased from top to bottom.

4. The lifting cylinder with a buffer structure according to claim 2, characterized in that: A guide sleeve (6) is also provided, and the guide sleeve (6) is arranged near the opening of the cylinder body (11) and is located above the buffer sleeve (8).

5. The lifting cylinder with a buffer structure according to claim 1, characterized in that: A dust ring (2) is provided at the opening of the cylinder body (11).

6. A forklift, characterized in that: A lifting oil cylinder with a buffer structure according to any one of claims 1 to 5 is used; there are two lifting oil cylinders (26), and an oil port (28) is added to the rod cavity of each of the two lifting oil cylinders (26), and the two oil ports (28) are connected by a pipeline.

7. The forklift according to claim 6, characterized in that: The pipeline is a rubber hose.

8. The forklift according to claim 6, characterized in that: The two oil ports are arranged at the same height.

9. A method for operating a forklift, characterized in that: A lifting cylinder with a buffer structure as claimed in any one of claims 1 to 5 is used; when oil enters the rodless chamber of the lifting cylinder (26), the piston rod (1) extends outward, and the mast of the forklift starts to lift from the lowest position; after the oil storage part of the cylinder enters the buffer sleeve (8), the hydraulic oil flows into the oil chamber (24) through the gap between the buffer sleeve (8) and the piston rod (1) through the throttle hole (23), and the hydraulic pressure generates back pressure due to the hydraulic oil being squeezed. The force generated by the back pressure causes the control valve (25) located at the bottom of the lifting cylinder (26) to overflow, and the flow rate supplied to the lifting cylinder by the hydraulic system becomes smaller, and the extension speed of the cylinder slows down.

Images