Outer cylinder type liquid-gas buffer

Abstract

The invention discloses an outer cylinder type hydraulic-pneumatic buffer. The outer cylinder type hydraulic-pneumatic buffer comprises a cylinder body, a piston rod and a damping groove structure. One end of the cylinder body is closed, and the other end is open; one end of the piston rod is inserted into the opening of the cylinder body and can move relative to the cylinder body; an oil liquid channel of a damping groove structure is arranged on the inner wall of the cylinder body. One end of the piston rod is a fixed piston, and the other end of the piston rod is a sealing ram; a movable piston capable of reciprocating in the axis direction is arranged in the air chamber, and an inflation hole and an inflation valve are arranged at the position of the sealing ram. When the buffer is pressed, the piston rod presses down hydraulic oil in the oil cavity, the hydraulic oil enters the piston rod through the oil channel, the movable piston is pushed to compress nitrogen in the air chamber, damping force is generated, and impact energy is absorbed. A traditional mandrel structure is omitted, and the device is simple in structure, low in cost, small in occupied space and suitable for scenes needing shock absorption, noise reduction and safety protection.

Description

Technical Field

[0001] The invention belongs to the technical field of buffers, and in particular relates to an external cylinder type liquid-gas buffer. Background Art

[0002] Hydro-pneumatic shock absorbers are widely used in industries such as industry, transportation, and construction. Their primary function is to convert impact energy into heat through the synergistic action of hydraulic oil and gas, thereby achieving shock absorption and cushioning. With the advancement of industrial technology, the structural design and performance requirements of hydro-pneumatic shock absorbers are also constantly improving.

[0003] At present, the common liquid-gas buffers on the market are mainly divided into two structures: piston type and core shaft type. The piston-type liquid-gas buffer usually includes components such as a cylinder body, a piston rod, a piston and an airbag. Its working principle is to compress the hydraulic oil and gas through the reciprocating motion of the piston in the cylinder body, thereby achieving a buffering effect. For example, a piston-type liquid-gas buffer disclosed in CN102359529A includes a cylinder body, a hollow piston rod, and a piston fixedly connected to the piston rod. A first oil chamber is formed between the bottom of the piston and the cylinder body, an airbag is installed in the piston rod, and a second oil chamber is formed between the bottom of the airbag and the inner end face of the hollow piston rod. A first throttling channel is provided between the first oil chamber and the second oil chamber. Although this structure can achieve a buffering effect, due to the complex internal structure and the large number of parts, it leads to high manufacturing costs and difficult maintenance.

[0004] Mandrel-type hydro-pneumatic dampers achieve their cushioning effect through relative motion between a mandrel and a cylinder. For example, CN119982821A discloses a mandrel-and-piston hydro-pneumatic damper. The mandrel is the core component of the damper. Traditional designs typically employ a conical structure, but this patent improves on this conical column structure to a cylindrical structure with a constant diameter. While this improvement reduces processing difficulty and cost, it still retains the mandrel as a core component, and the overall structure remains relatively complex.

[0005] Furthermore, the hydro-gas buffer disclosed in CN110953280B utilizes a partially internal, partially external piston assembly structure, which serves as both a liquid chamber separation component and a force transmission component, making the buffer structure more compact. CN202228582U proposes a piston-type hydro-gas buffer that improves sealing and maintains buffering performance. This achieves a better buffering effect by providing multiple oil chambers and throttling channels.

[0006] However, the liquid-gas buffers in the existing technology generally have the following problems: First, the traditional buffer structure design includes a core shaft, which makes the overall structure complex and has a large number of parts, which not only increases the manufacturing cost, but also increases the difficulty of subsequent maintenance and repair; second, the complex internal structure causes the buffer to be larger in size, which makes it difficult to install in application scenarios with limited space; in addition, the core shaft structure in the traditional design requires precision processing, and has high requirements for processing accuracy, which further increases the manufacturing cost.

[0007] Therefore, there is an urgent need for a liquid-gas buffer with a simple structure, low cost, easy maintenance and good buffering effect to meet the actual needs in industrial applications. Summary of the Invention

[0008] In order to solve the technical problems that traditional buffer structure designs all include a core shaft, complex structure, and high manufacturing, maintenance and repair costs, and to reduce the number of parts, simplify the structure, reduce costs, save space and provide efficient and reliable impact protection, the present invention provides an external cylinder type liquid-gas buffer.

[0009] The technical solution adopted by the present invention to solve its technical problems is: to provide an external cylinder type liquid-gas buffer, including: a cylinder body, one end of which is closed and the other end is open, the closed end is the cylinder bottom, which provides support and closes the oil chamber; a piston rod, one end of the piston rod is inserted into the opening of the cylinder body, and can move relative to the cylinder body; the interior of the cylinder body is an oil chamber, the interior of the piston rod is an air chamber, and the inner wall of the cylinder body is provided with an oil channel with a damping groove structure.

[0010] A further technical solution of the present invention is: one end of the piston rod is a fixed piston, and the other end is a sealing impact head. The inside is a hollow air chamber, and a movable piston that can move back and forth along the piston axis is provided in the air chamber. An inflation hole and an inflation valve are provided at the sealing impact head.

[0011] A further technical solution of the present invention is: a sealing end cover is provided at the end of the cylinder body and the connection between the piston rod and the cylinder body, and the sealing end cover is fixed to the cylinder body by a bolt assembly; the inner diameter of the sealing end cover is smaller than the inner diameter of the cylinder body and larger than the inner diameter of the piston rod, and a stepped limit piece is formed at the end of the cylinder opening, and the end of the piston rod is also provided with a protruding structure adapted to the limit piece, thereby achieving the purpose of limiting the moving stroke of the piston rod in the cylinder body.

[0012] A further technical solution of the present invention is that a plurality of sealing members are provided on the contact surface between the fixed piston and the interior of the cylinder body, and on the contact surface between the stopper and the outside of the piston rod, so as to improve the sealing effect.

[0013] A further technical solution of the present invention is that a buffer pad is provided at the end of the sealing impact head.

[0014] A further technical solution of the present invention is that the cross section of the damping groove structure gradually narrows from the open end to the closed end of the cylinder body, and the density gradually decreases.

[0015] A further technical solution of the present invention is that the damping groove structure is a plurality of linear grooves, the plurality of linear grooves are coaxial with the cylinder body, and are distributed in an annular array on the inner diameter surface of the cylinder body.

[0016] A further technical solution of the present invention is: the damping groove structure is a spiral grid-type groove, and the spiral grid-type grooves are evenly distributed on the inner diameter surface of the cylinder body.

[0017] A further technical solution of the present invention is that the damping groove structure is a composite groove structure in which straight lines and spiral grids are alternately distributed, forming a "conduction-dissipation" dual-mode coupling.

[0018] The beneficial effects of this invention include eliminating the core shaft structure in traditional designs, overcoming industry prejudices, reducing the number of components, and achieving a simpler overall structure, lowering costs and occupying less space. This makes it easier to install in space-constrained equipment, while also simplifying subsequent maintenance and reducing repair costs. When the buffer is compressed by an external force, the piston rod moves toward the cylinder. One end of the piston rod presses down on the hydraulic oil in the oil chamber. Under pressure, the hydraulic oil enters the piston rod through the oil channel. As the oil passes through the small orifice, its flow rate increases and its pressure decreases. According to Bernoulli's equation, flow rate and pressure are inversely proportional. At this point, the oil must overcome flow resistance to generate a damping force. The damping force converts the kinetic energy of the impact into internal energy (heat) of the oil. Simultaneously, the nitrogen in the air chamber is compressed, generating a reaction force, with some of the energy being absorbed by the compressed nitrogen. This combined damping effect of the hydraulic oil and nitrogen provides efficient and reliable impact protection. In particular, it provides an immediate damping response with a short response time under high-speed impacts. The damping force transitions smoothly with piston displacement, avoiding sudden shocks. Through the composite groove structure with alternating distribution of straight and spiral grid types, the spiral grid structure is dominant in the low-speed stage to achieve flexible buffering, while the straight structure is activated in the high-speed stage to provide rigid support, further improving the buffering effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 This is a schematic structural diagram of the outer cylinder type liquid-gas buffer of the present invention; Figure 2 Schematic diagram of the structure of the linear groove in the present invention; Figure 3 Schematic diagram of the structure of the spiral grid groove in the present invention; Figure 4 Schematic diagram of the composite groove structure of the present invention. DETAILED DESCRIPTION

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1 An external cylinder type liquid-gas buffer, see Figure 1 The cylinder body 1 comprises a cylinder body 1, a piston rod 3, an oil chamber 4, and an air chamber 5. The cylinder body 1 is closed at one end, forming a cylinder bottom 2, and is open at the other end. The cylinder bottom 2 provides support and seals the oil chamber 4. One end of the piston rod 3 is inserted into the opening of the cylinder body 1 and is movable relative to the cylinder body 1. The interior of the cylinder body 1 is the oil chamber 4, and the interior of the piston rod 3 is the air chamber 5. The inner wall of the cylinder body 1 is provided with an oil channel 6 with a damping groove structure.

[0022] At one end of the piston rod 3 is a fixed piston 7, which fits tightly within the cylinder body 1 to ensure stability during movement. At the other end is a sealed impactor 8, which is responsible for direct contact with external impact objects and withstands the impact force. The interior of the piston rod 3 is hollow, forming an air chamber 5. This air chamber 5 cleverly houses a movable piston 9 that can reciprocate along the piston axis. The sealed impactor 8 is also equipped with an inflation hole and an inflation valve 10 to facilitate the inflation of the air chamber 5. Nitrogen is injected into the right side of the movable piston 9 through the inflation valve 10. Under the action of the air pressure, the movable piston 9 moves leftward, close to the fixed piston 7, thereby forming a stable nitrogen chamber 5 to the right of the movable piston 9.

[0023] In order to ensure the sealing performance of the buffer and prevent the leakage of hydraulic oil and nitrogen, a sealing end cover 11 is specially provided at the end of the cylinder body 1 and the connection between the piston rod 3 and the cylinder body 1. The sealing end cover 11 is firmly fixed to the cylinder body 1 by a bolt assembly 17. Its inner diameter is designed to be smaller than the inner diameter of the cylinder body 1 but larger than the inner diameter of the piston rod 3, thereby forming a stepped limiter at the opening of the cylinder body 1. The end of the piston rod 3 is correspondingly configured as a raised structure adapted to the limiter. This design effectively limits the movement of the piston rod 3 in the cylinder body 1 and prevents it from being damaged due to excessive movement. At the same time, a number of seals 12 are provided on the contact surface between the fixed piston 7 and the inside of the cylinder body 1, as well as on the contact surface between the limiter and the outside of the piston rod 3, which further improves the sealing effect and ensures the long-term stable operation of the buffer.

[0024] A buffer pad 13 is provided at the end of the sealing impact head 8, preferably made of rubber. The rubber pad has good elasticity and wear resistance, can effectively absorb part of the energy during the impact, reduce the impact on the piston rod 3 and the sealing structure, and extend the service life of the buffer.

[0025] As one of the core design elements of the external cylinder type liquid-gas buffer, the damping groove structure realizes precise control of the flow characteristics of the hydraulic oil through scientific and reasonable geometric form and layout planning, thereby achieving dynamic optimization and smooth transition of the damping force. Extending from the open end to the closed end of the cylinder body 1, the cross-sectional dimensions of the damping groove are designed to gradually narrow, and the distribution density of the groove is also reduced accordingly. This progressive design strategy allows the hydraulic oil to naturally adjust its flow rate and pressure distribution according to the width and density of the flow channel when flowing through different areas, thereby ensuring that the damping force changes continuously and smoothly with the movement of the piston, avoiding shock and vibration caused by sudden changes in the damping force.

[0026] Specifically, the damping groove structure can flexibly adopt a variety of innovative forms according to actual application needs and performance requirements: In a preferred embodiment, see Figure 2 , the damping grooves are designed as a number of straight grooves 14. These grooves maintain a strict coaxial relationship with the cylinder body 1, and are distributed in a ring array along the inner diameter surface of the cylinder body 1. The design structure of the straight grooves 14 is simple and efficient. Its straight flow path enables the hydraulic oil to quickly form a stable flow field under high-speed impact, thereby providing an immediate damping response. This immediacy is crucial for absorbing sudden impact energy. It can establish sufficient damping force in a very short time, effectively slowing down the movement speed of the piston, and preventing equipment damage caused by excessive impact. At the same time, the uniform distribution of the straight grooves 14 also ensures the balance of the damping force in the circumferential direction, avoiding instability caused by excessive or insufficient local damping force.

[0027] In another preferred embodiment, see Figure 3 , the damping groove adopts the design of spiral grid groove 15. The spiral grid groove 15 is wrapped around the inner diameter surface of the cylinder body 1 in an elegant and continuous manner. Its unique spiral grid shape not only gives the buffer a more beautiful appearance, but more importantly, it realizes a smooth transition of the buffering force with the displacement of the piston. During the movement of the piston, the spiral grid groove 15 guides the hydraulic oil to flow along the spiral grid path. This flow method makes the change of the damping force more gradual and gentle, effectively avoiding the impact and damage to the buffer caused by the sudden change of the damping force. At the same time, the design of the spiral grid groove 15 also enhances the turbulence of the hydraulic oil and improves the energy dissipation efficiency, thereby further improving the performance stability of the buffer.

[0028] In another preferred embodiment, see Figure 4, the damping groove structure is designed as a composite groove structure 16 with alternating distribution of straight lines and spiral grid types. This composite structure cleverly combines the respective advantages of the straight grooves 14 and the spiral grid grooves 15, forming a unique mechanism of "flow diversion-dissipation" dual-mode coupling. In the low-speed stage, the spiral grid structure occupies a dominant position. Its soft flow characteristics and good energy dissipation capabilities enable the buffer to achieve flexible buffering, effectively absorb low-speed impact energy, and protect the equipment from tiny vibrations. When entering the high-speed stage, the straight structure is activated. Its straight flow channel and fast response characteristics provide rigid support for the buffer, preventing the buffer from being over-compressed due to excessive impact force, thereby ensuring the safe operation of the equipment. This composite groove structure 16 that automatically switches the working mode according to speed fully demonstrates the design flexibility and intelligence of the external cylinder liquid-gas buffer, enabling it to adapt to more complex and changing working conditions.

[0029] The damper's operating principle: When the damper is compressed by an external force, the piston rod 3 moves toward the cylinder 1, one end of which presses down on the hydraulic oil in the oil chamber 4. Under pressure, the hydraulic oil enters the piston rod 3 through the oil channel 6, pushing the piston 9 to the left, exerting a rightward thrust on the piston 9. Simultaneously, the nitrogen in the air chamber 5 is compressed, absorbing some of the impact energy. As the hydraulic oil passes through the orifice, its flow rate increases and its pressure decreases. According to Bernoulli's equation, flow rate and pressure are inversely proportional. At this point, the oil must overcome flow resistance, generating a damping force. The damping force converts the kinetic energy of the impact into internal heat energy within the oil, effectively dissipating the energy. Simultaneously, the compressed nitrogen in the air chamber 5 creates a reaction force, absorbing some of the energy, further enhancing the damping effect. After the compression stroke is complete, the nitrogen exerts a leftward restoring force on the piston 9, returning the piston rod 3 to its original position, ready for the next impact.

[0030] This external cylinder-type liquid-gas buffer eliminates the core shaft structure of traditional designs, overcoming industry prejudice and achieving major structural innovation. While maintaining excellent buffering effects, the number of components is reduced, making the overall structure simpler and more compact. This not only reduces manufacturing costs, but also reduces the space required, making it easier to install in space-constrained equipment. In addition, the buffer is easy to maintain and has lower repair costs. With the combined buffering of hydraulic oil and nitrogen, efficient and reliable impact protection is achieved. It is widely used in various scenarios requiring shock absorption, noise reduction and safety protection, such as rail transportation, aerospace, heavy machinery and other fields, providing strong support for the development of modern industry.

[0031] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An external cylinder type liquid-gas buffer, characterized in that: include: A cylinder body (1) having one closed end and an open end, the closed end being the cylinder bottom (2); A piston rod (3), one end of which is inserted into the opening of the cylinder body (1) and is movable relative to the cylinder body (1); The interior of the cylinder body (1) is an oil chamber (4), the interior of the piston rod (3) is an air chamber (5), and the inner wall of the cylinder body (1) is provided with an oil channel (6) with a damping groove structure.

2. The external cylinder type liquid-gas buffer according to claim 1, characterized in that: One end of the piston rod (3) is a fixed piston (7), and the other end is a sealing impact head (8). The interior is a hollow air chamber (5). A movable piston (9) that can reciprocate along the piston axis is provided in the air chamber (5). An inflation hole and an inflation valve (10) are provided at the sealing impact head (8).

3. The external cylinder type liquid-gas buffer according to claim 2, characterized in that: A sealing end cover (11) is provided at the end of the cylinder body (1) and at the connection between the piston rod (3) and the cylinder body (1). The sealing end cover (11) is fixed to the cylinder body (1) by a bolt assembly (17); the inner diameter of the sealing end cover (11) is smaller than the inner diameter of the cylinder body (1) and larger than the inner diameter of the piston rod (3). A stepped stopper is formed at the end of the opening of the cylinder body (1). The end of the piston rod (3) is also provided with a protruding structure adapted to the stopper, thereby limiting the movement stroke of the piston rod (3) in the cylinder body (1).

4. The external cylinder type liquid-gas buffer according to claim 3, characterized in that: A plurality of sealing members (12) are provided on the contact surface between the fixed piston (7) and the inner part of the cylinder body (1), and on the contact surface between the stopper and the outer part of the piston rod (3).

5. The external cylinder type liquid-gas buffer according to claim 4, characterized in that: A buffer pad (13) is provided at the end of the sealing impact head (8).

6. The external cylinder type liquid-gas buffer according to claim 1, characterized in that: The cross section of the damping groove structure gradually narrows from the open end to the closed end of the cylinder body (1), and the density gradually decreases.

7. The external cylinder type liquid-gas buffer according to claim 6, characterized in that: The damping groove structure is a plurality of linear grooves (14), the plurality of linear grooves (14) are coaxial with the cylinder body (1), and are distributed in an annular array on the inner diameter surface of the cylinder body (1).

8. The external cylinder type liquid-gas buffer according to claim 6, characterized in that: The damping groove structure is a spiral grid-type groove (15), and the spiral grid-type grooves (15) are evenly distributed on the inner diameter surface of the cylinder body (1).

9. The external cylinder type liquid-gas buffer according to claim 6, characterized in that: The damping groove structure is a composite groove structure (16) in which straight lines and spiral grids are alternately distributed, forming a "conduction-dissipation" dual-mode coupling.

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