Two-stage pneumatic pressure accumulator and fork truck

Abstract

The utility model discloses a two-stage inflation pressure energy accumulator and fork-lift truck, including the cylinder, be equipped with first piston, second piston in the cylinder, first piston, second piston slide along the inner wall of cylinder, and the inner chamber of cylinder is divided into first inflation area, oil filling area, second inflation area by first piston, second piston, one end of cylinder is equipped with first inflation port, oil filling port, and the other end of cylinder is equipped with second inflation port, and first inflation port communicates with first inflation area, and second inflation port communicates with second inflation area, and oil filling port communicates with oil filling area through the oil injection stem set up in the cylinder. The utility model discloses oil filling port, inflation port all set up along the longitudinal direction of cylinder, can be bound together with the oil cylinder, saves the installation and maintenance space, and the oil injection stem sets up in the cylinder interior, does not need to open the hole on the side of cylinder barrel, has reduced the processing manufacturing complexity of cylinder barrel, has two inflation pressure energy accumulator, can satisfy the demand of fork-lift truck maximum weight goods and loading medium goods weight simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of energy storage technology, and in particular to a two-stage air pressure energy storage device and a forklift truck. Background Technology

[0002] Currently, the shock absorption solutions for forklifts on the market mainly focus on the chassis. When the forks are loaded with goods, the ride is quite bumpy when quickly passing over obstacles such as speed bumps, affecting the driving experience. The mainstream solution on the market is to add an accumulator to the luffing cylinder. However, existing accumulator products only have one charging pressure. The hydraulic oil charging pressure changes with the weight of the load on the forks. The optimal shock absorption charging pressure P0 = hydraulic oil charging pressure P1 × 70%. When the forks are loaded with the maximum weight of goods (charging pressure P0...), the optimal shock absorption pressure is determined by the formula: P0 = hydraulic oil charging pressure P1 × 70%. 0max When loading medium cargo weight (inflation pressure P) 0mid P0 represents two inflation pressures with a significant difference; for certain vehicle models, P... 0max Hydraulic oil filling pressure P when the weight of the cargo is greater than medium 1mid This accumulator has completely failed. Two accumulators are connected in parallel, with one accumulator pressurized by gas P. 0max Another accumulator gas pressurization P 0mid While this can effectively reduce vibration, the two accumulators are large in size and have many connection points, making them prone to leakage and posing a safety hazard.

[0003] Chinese patent CN220314644U discloses a piston-type accumulator for a vehicle suspension system with high and low pressure chambers. It includes a cylinder, two cylinder heads with vent holes corresponding to the upper and lower ends of the cylinder, two pistons installed in the cylinder dividing it into a low-pressure chamber, an oil chamber, and a high-pressure chamber, arranged vertically, two oil passages on the side of the cylinder and communicating with the oil chambers, and two charging valves corresponding to the vent holes. This type of piston-type accumulator requires openings on the side of the cylinder to connect to the intermediate chambers, making cylinder manufacturing difficult. The side-mounted oil ports require installation space larger than the cylinder diameter for connecting oil pipes, which is not feasible on forklifts. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention proposes a two-stage inflatable pressure accumulator that reduces leakage points and saves installation and maintenance space.

[0005] The technical solution of this utility model is as follows: A two-stage pneumatic pressure accumulator includes a cylinder, in which a first piston and a second piston are provided. The first piston and the second piston slide along the inner wall of the cylinder. The inner cavity of the cylinder is divided into a first pneumatic zone, an oil filling zone, and a second pneumatic zone by the first piston and the second piston. One end of the cylinder is provided with a first pneumatic port and an oil filling port, and the other end of the cylinder is provided with a second pneumatic port. The first pneumatic port is connected to the first pneumatic zone, and the second pneumatic port is connected to the second pneumatic zone. The oil filling port is connected to the oil filling zone through an oil injection rod disposed in the cylinder.

[0006] Both the oil filling port and the air filling port are set along the longitudinal direction of the cylinder and can be bundled together with the oil cylinder, saving installation and maintenance space. With two accumulators for charging pressure, it can simultaneously meet the needs of the forklift when loading the maximum weight of goods and when loading medium weight of goods, saving space, reducing leakage points, and improving driving experience and safety.

[0007] In one embodiment, the cylindrical body includes a first end cap, a first cylindrical body, an intermediate cylindrical body, a second cylindrical body, and a second end cap that are fixedly connected in sequence. The first cylindrical body is fixedly connected to the intermediate cylindrical body, and the intermediate cylindrical body is threadedly connected to the second cylindrical body.

[0008] In one embodiment, the inner diameter of the intermediate cylinder is smaller than the inner diameters of the first and second cylinders. A first limiting surface is formed on the end face of the intermediate cylinder near the first cylinder, and a second limiting surface is formed on the end face of the intermediate cylinder near the second cylinder. When the first and second pistons move within the cylinder, the first and second limiting surfaces restrict their stroke, ensuring the balance between the air-filling and oil-filling zones within the cylinder.

[0009] In one embodiment, one end of the injection rod is fixed to the first end cap, and the other end of the injection rod does not extend beyond the second limiting surface. The first piston is located inside the first cylinder and is slidably mounted on the injection rod. The second piston is located inside the second cylinder. The second piston is a solid piston that slides along the inner wall of the cylinder within the second inflation zone. The maximum length of the injection rod is set to prevent it from entering the inflation zone and affecting the movement of the second piston.

[0010] In one embodiment, the first piston is a hollow piston. The inner circumferential surface of the first piston in contact with the oil injection rod is provided with an inner seal, the outer circumferential surface of the first piston in contact with the inner wall of the first cylinder is provided with a first outer seal, and the outer circumferential surface of the second piston in contact with the inner wall of the second cylinder is provided with a second outer seal. These seals are provided to prevent gas from the pneumatic filling zone from entering the oil filling zone, and also to prevent hydraulic oil from the oil filling zone from entering the pneumatic filling zone, thus ensuring stable operation of both zones.

[0011] In one embodiment, at least one support ring is provided on the outer peripheral surface of the first piston and the second piston. The support ring on the outer periphery of the piston is provided to prevent excessive compression of the piston by the strong thrust, to prevent piston deformation, and to ensure the normal operation of the accumulator.

[0012] In one embodiment, the first air inlet and the oil inlet are disposed on the first end cap, and the second air inlet is disposed on the second end cap.

[0013] In one embodiment, the first and second air inlets are equipped with air inlets and air valves. The air inlets and air valves are used to control the air intake of the accumulator, so that the accumulator's operating state reaches the most stable state.

[0014] In one embodiment, the injection rod is a hollow rod-shaped structure. The hollow rod-shaped injection rod allows hydraulic oil to enter the filling area through the filling port, and the rod-shaped structure also serves as a motion guide for the first piston, allowing the first piston to slide within the cylinder.

[0015] Based on the same inventive concept, this utility model also discloses a forklift truck, including a luffing hydraulic cylinder and the aforementioned two-stage pneumatic pressure accumulator. The two-stage pneumatic pressure accumulator is connected to the rodless chamber of the luffing hydraulic cylinder, forming a boom luffing actuator with the luffing hydraulic cylinder.

[0016] Beneficial effects 1. The oil filling port and air filling port of this utility model are both set along the longitudinal direction of the cylinder, and can be tied together with the oil cylinder, saving installation and maintenance space.

[0017] 2. The oil injection rod of this utility model is set inside the cylinder body, eliminating the need to open a hole on the side of the cylinder to conduct the hydraulic oil chamber in the middle, thus reducing the complexity of the cylinder manufacturing process.

[0018] 3. This utility model has an accumulator with two inflation pressures, which can simultaneously meet the needs of forklifts when loading the maximum weight of goods and when loading medium weight goods, saving space, reducing leakage points, and improving driving experience and safety. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of one embodiment of the present utility model; Figure 2 for Figure 1 AA section diagram; Figure 3 for Figure 1 Explosion-proof diagram of the structure; Figure 4 This is a schematic diagram of the internal structure of the cylindrical body of this utility model; Figure 5 This is a schematic diagram of the boom luffing actuator composed of the present invention and the luffing hydraulic cylinder.

[0020] In the figure, 1. First cylinder, 2. Second cylinder, 3. Intermediate cylinder, 4. First piston, 5. Second piston, 6. First end cap, 7. Second end cap, 8. Oil injection rod, 9. First air filling zone, 10. Second air filling zone, 11. Oil filling zone, 12. First air filling port, 13. Second air filling port, 14. Oil filling port, 15. Air filling valve, 16. Inner seal, 17. First outer seal, 18. Second outer seal, 19. Support ring, 20. Luffing hydraulic cylinder, 21. Two-stage air pressure accumulator, 301. First limiting surface, 302. Second limiting surface. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "or / and" as used herein includes any and all combinations of one or more of the associated listed items.

[0023] like Figures 1-4 As shown, the two-stage air-filled pressure accumulator 21 disclosed in this embodiment includes a first cylinder 1, a second cylinder 2, an intermediate cylinder 3, a first end cap 6, and a second end cap 7. The first cylinder 1 and the intermediate cylinder 3 are fixedly connected, and the intermediate cylinder 3 and the second cylinder 2 are threadedly connected. The first end cap 6 is located at the end of the first cylinder 1 away from the intermediate cylinder 3, and the second end cap 7 is located at the end of the second cylinder 2 away from the intermediate cylinder 3. A first piston 4 is provided inside the first cylinder 1, and a second piston 5 is provided inside the second cylinder 2. The first piston 4 and the second piston 5 slide along the inner wall of the cylinder. The inner cavity of the cylinder is divided into a first air-filling zone 9, an oil-filling zone 11, and a second air-filling zone 10 by the first piston 4 and the second piston 5.

[0024] In this embodiment, the inner diameter of the intermediate cylinder 3 is smaller than the inner diameters of the first cylinder 1 and the second cylinder 2. A first limiting surface 301 is formed on the end face of the intermediate cylinder 3 near the first cylinder 1, and a second limiting surface 302 is formed on the end face of the intermediate cylinder 3 near the second cylinder 3. When the first piston 4 and the second piston 5 move within the cylinder, the first limiting surface 301 and the second limiting surface 302 restrict their stroke, ensuring the balance between the air-filling zone and the oil-filling zone within the cylinder.

[0025] In this embodiment, the first inflation zone 9 refers to the area between the first end cap 6 and the first piston 4, the oil filling zone 11 refers to the area between the first piston 4 and the second piston 5, and the second inflation zone 10 refers to the area between the second piston 5 and the second end cap 7. Since the positions of the first piston 4 and the second piston 5 change when the accumulator is working, the corresponding inflation zone and oil filling zone will also change accordingly.

[0026] In this embodiment, the first end cap 6 is provided with a first air inlet 12 and an oil inlet 14, and the second end cap 7 is provided with a second air inlet 13. The first air inlet 12 is connected to the first air inlet 9, and the second air inlet 13 is connected to the second air inlet 10. The oil inlet 14 is connected to the oil inlet 11 through an oil injection rod 8 provided in the cylinder. The first air inlet 9 and the second air inlet 10 are provided with air inlet valves.

[0027] In this embodiment, one end of the oil injection rod 8 is fixed to the first end cap 6. The first piston 4 is a hollow piston and is slidably mounted on the oil injection rod 8. The inner circumferential surface of the first piston 4 in contact with the oil injection rod 8 is provided with an inner seal 16, and the outer circumferential surface of the first piston 4 in contact with the inner wall of the first cylinder 1 is provided with a first outer seal 17. The second piston 5 is a solid piston that slides along the inner wall of the cylinder within the second inflation zone 10. The outer circumferential surface of the second piston 5 in contact with the inner wall of the second cylinder 2 is provided with a second outer seal 17. The seals are provided to prevent gas from the inflation zone from entering the oil filling zone and to prevent hydraulic oil from the oil filling zone from entering the inflation zone, thus ensuring the stable operation of both the inflation zone and the oil filling zone.

[0028] In this embodiment, the other end of the oil injection rod 8 does not exceed the second limiting surface 302 of the intermediate cylinder 3, and the maximum length of the oil injection rod 8 is set to prevent the oil injection rod 8 from entering the inflation zone and affecting the movement of the second piston 5.

[0029] In this embodiment, the oil injection rod 8 is a hollow rod-shaped structure. The hollow rod-shaped oil injection rod 8 allows hydraulic oil to enter the filling zone 11 through the filling port, and the rod-shaped structure can also serve as a motion guide for the first piston 4, allowing the first piston 4 to slide within the cylinder.

[0030] In this embodiment, two support rings 19 are provided on the outer peripheral surfaces of the first piston 4 and the second piston 5. The support rings 19 are provided on the outer peripheral surface of the piston to prevent the piston from being excessively squeezed by the strong thrust, to prevent the piston from deforming, and to ensure the normal operation of the accumulator.

[0031] like Figure 5As shown, this embodiment also discloses a forklift truck, including a luffing hydraulic cylinder 20 and a two-stage air pressure accumulator 21. The two-stage air pressure accumulator 21 is connected to the rodless chamber of the luffing hydraulic cylinder 20 and forms a boom luffing actuator with the luffing hydraulic cylinder 20. Before use, the first and second air chambers of the accumulator are filled with inert gas at 18.5 MPa (pressure varies depending on the vehicle model) and 12 MPa (pressure varies depending on the vehicle model), respectively.

[0032] After the forks load the cargo, the pressure in the rodless chamber of the luffing hydraulic cylinder 20 will vary depending on the weight of the cargo. The accumulator 21 will be filled with hydraulic oil of the same pressure through the filling port. If the pressure in the filling zone 11 is greater than the filling pressure in the second filling zone 10 but less than the filling pressure in the first filling zone 9, the second piston 5 will move inside the second cylinder 2 to compress the gas in the second filling zone 10, while the first piston 4 remains stationary relative to the first cylinder 1 until the pressures in the two chambers of the filling zone 11 and the second filling zone 10 are balanced (corresponding to medium load).

[0033] If the pressure in the oil filling zone 11 is greater than the inflation pressure in the second inflation zone 10, the second piston 5 moves inside the second cylinder 2 to compress the gas in the second inflation zone 10, and the first piston 4 moves inside the first cylinder 1 to compress the gas in the first inflation zone 9, until the pressures of the three chambers—oil filling zone 11, first inflation zone 9, and second inflation zone 10—are balanced (corresponding to heavy load).

[0034] If the pressure in the oil filling zone 11 is less than the inflation pressure in the second inflation zone 10, the corresponding cargo weight is less than 500KG (the weight varies depending on the vehicle model), and the risk of tipping over is greatly reduced. In this embodiment, the accumulator does not intervene in the operation (corresponding to light load).

[0035] When a forklift loads goods and passes over uneven surfaces, the accumulator undergoes a process of first draining oil, then filling oil, and then stabilizing. When passing over bumpy surfaces such as speed bumps, the process is the same: first filling oil, then draining oil, and then stabilizing. During this process, the oil exchange occurs between the accumulator and the hydraulic cylinder, and the oil in the hydraulic system does not participate.

[0036] When the accumulator is discharging oil under medium load, the gas volume in the second charging zone 10 increases, pushing the second piston 5 to move closer to the intermediate cylinder 3, thereby pushing the hydraulic oil in the oil charging zone 11 to flow from the oil charging port 14 into the hydraulic cylinder until the second piston 5 contacts the intermediate cylinder 3.

[0037] When the heavy-load accumulator is discharging oil, the gas volume in the first charging zone 9 and the second charging zone 10 both increase, pushing the second piston 5 to move closer to the intermediate cylinder 3 and the first piston 4 to move closer to the intermediate cylinder 3, thereby pushing the hydraulic oil in the oil filling zone 11 to flow from the oil filling port 14 into the hydraulic cylinder until the first piston 4 and the second piston 5 contact the intermediate cylinder 3.

[0038] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A two-stage gas-filled pressure accumulator, characterized in that: The cylinder includes a first piston (4) and a second piston (5) inside the cylinder. The first piston (4) and the second piston (5) slide along the inner wall of the cylinder. The inner cavity of the cylinder is divided into a first air-filling zone (9), an oil-filling zone (11), and a second air-filling zone (10) by the first piston (4) and the second piston (5). One end of the cylinder is provided with a first air-filling port (12) and an oil-filling port (14), and the other end of the cylinder is provided with a second air-filling port (13). The first air-filling port (12) is connected to the first air-filling zone (9), and the second air-filling port (13) is connected to the second air-filling zone (10). The oil-filling port (14) is connected to the oil-filling zone (11) through an oil injection rod (8) provided in the cylinder.

2. The two-stage gas-pressure accumulator according to claim 1, characterized in that: The cylinder includes a first end cap (6), a first cylinder (1), an intermediate cylinder (3), a second cylinder (2), and a second end cap (7) that are fixedly connected in sequence. The first cylinder (1) is fixedly connected to the intermediate cylinder (3), and the intermediate cylinder (3) is threadedly connected to the second cylinder (2).

3. The two-stage gas-pressure accumulator according to claim 2, characterized in that: The inner diameter of the intermediate cylinder (3) is smaller than the inner diameter of the first cylinder (1) and the second cylinder (2). The end face of the intermediate cylinder (3) near the first cylinder (1) forms a first limiting surface (301), and the end face of the intermediate cylinder (3) near the second cylinder (2) forms a second limiting surface (302).

4. The two-stage gas-pressure accumulator according to claim 3, characterized in that: One end of the oil injection rod (8) is fixed on the first end cap (6), and the other end of the oil injection rod (8) does not exceed the second limiting surface (302). The first piston (4) is located inside the first cylinder (1) and is slidably mounted on the oil injection rod (8). The second piston (5) is located inside the second cylinder (2).

5. The two-stage gas-pressure accumulator according to claim 4, characterized in that: The first piston (4) is a hollow piston. The inner circumferential surface of the first piston (4) in contact with the oil injection rod (8) is provided with an inner seal (16). The outer circumferential surface of the first piston (4) in contact with the inner wall of the first cylinder (1) is provided with a first outer seal (17). The outer circumferential surface of the second piston (5) in contact with the inner wall of the second cylinder (2) is provided with a second outer seal (18).

6. The two-stage gas-pressure accumulator according to claim 4, characterized in that: The outer circumferential surfaces of the first piston (4) and the second piston (5) are provided with at least one support ring (19).

7. The two-stage gas-pressure accumulator according to claim 2, characterized in that: The first air inlet (12) and oil inlet (14) are located on the first end cap (6), and the second air inlet (13) is located on the second end cap (7).

8. The two-stage gas-pressure accumulator according to claim 7, characterized in that: The first inflation port (12) and the second inflation port (13) are equipped with inflation valves.

9. The two-stage gas-pressure accumulator according to any one of claims 1-8, characterized in that: The oil injection rod (8) is a hollow rod-shaped structure.

10. A forklift truck, comprising a luffing hydraulic cylinder, characterized in that: It also includes a two-stage pneumatic pressure accumulator as described in any one of claims 1-9, wherein the two-stage pneumatic pressure accumulator is connected to the rodless chamber of the luffing hydraulic cylinder and together with the luffing hydraulic cylinder forms a boom luffing actuator.

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