Floating seal oil cylinder

Abstract

A floating seal oil cylinder, comprising a cylinder barrel, a piston, a piston seal, a piston rod, a support, a floating device, and a floating seal. The piston and the piston rod are arranged in the cylinder barrel; the piston and an inner wall of the cylinder barrel are sealed by means of the piston seal; a tail end of the cylinder barrel is connected to the floating device; the support is arranged between the floating device and the piston rod; the floating device and the piston rod are sealed by means of the floating seal. In the present application, the floating seal is arranged in the floating device to be in contact with the piston rod, and the floating device is used to solve the problem of lateral force of the oil cylinder, so that an oil cylinder seal is no longer worn due to lateral force, thereby prolonging the service life of the oil cylinder and solving environmental protection problems such as leakage.

Description

A floating sealing cylinder Technical Field

[0001] This invention relates to the field of hydraulic cylinders, and in particular to a floating sealed hydraulic cylinder. Background Technology

[0002] Currently, hydraulic cylinder rod seals are all of the traditional type, with the cylinder barrel and piston rod connected and fixed by a rigid guide sleeve. When the hydraulic cylinder is used under lateral force conditions, the piston rod undergoes radial bending deformation due to the lateral force. Since the guide sleeve is larger in radial dimension than the piston rod and has a relatively stronger rigidity, uneven wear occurs between the guide sleeve and the deformed piston rod under lateral force. With the friction coefficient remaining constant, this increases the compressive force between the sealing ring and the piston rod, leading to accelerated seal wear and gradual failure of the rod seal. Under prolonged lateral force, leakage occurs in the rod seal, reducing the safety factor, polluting the environment, reducing efficiency, and causing serious energy loss. To address this, this invention proposes a floating sealing hydraulic cylinder to solve the problem of the hydraulic cylinder rod seal being affected by lateral force. The guide sleeve structure is replaced by a floating sealing device. The support inside the floating device contacts the piston rod, providing guidance for the piston rod. The flexible part of the flexible sealing device absorbs the lateral force generated by the bending deformation of the piston rod, eliminating lateral force on the piston rod seal, reducing the wear of the sealing ring, extending the service life of the hydraulic cylinder, and preventing hydraulic leakage and external contamination from entering the hydraulic cylinder. Summary of the Invention

[0003] The purpose of this invention is to propose a floating sealing cylinder, which employs a floating device with an internal floating seal. When the piston rod is subjected to lateral force and undergoes radial bending deformation, the floating device and the floating seal bend and deform together with the piston rod, thereby solving the problem of the seal being affected by lateral force on the cylinder's service life and optimizing the sealing system.

[0004] A floating sealing cylinder includes a cylinder (1), a piston (2), a piston seal (3), a piston rod (4), a support (5), a floating device (6), and a floating seal (7). The cylinder (1) is provided with a piston (2) and a piston rod (4). The piston (2) is sealed to the inner wall of the cylinder (1) by the piston seal (3). The tail end of the cylinder (1) is connected to the floating device (6). The support (5) is provided between the floating device (6) and the piston rod (4). The floating device (6) and the piston rod (4) are sealed by the floating seal (7).

[0005] The floating device (6) includes an inner end 61, an outer end 62 and an intermediate connection 63. The inner end 61 is connected to the cylinder 1. The connection method can be thread, bolt, flange, etc. The inner end 61 is provided with a support (5) that contacts the piston rod (4) to provide support and guidance for the piston rod (4). The outer end 62 of the floating device (6) is provided with a floating seal (7) and a support (5). The floating seal (7) plays a sealing role and can prevent leakage of the rod cavity inside and the entry of external contaminants. The outer end of the floating device (6) is provided with a support (5) to support and prevent rod scratching. The intermediate connection 63 is a flexible part. As the piston rod deforms under force, it provides absolute sealing and pressure resistance without losing flexibility.

[0006] The inner end (61), outer end (62), and intermediate connection (63) of the floating device (6) are made of metal. The floating device is made entirely of metal, and the intermediate connection is made of a corrugated pipe structure. Corrosion-resistant materials are selected. Considering welding, forming, and the performance-price ratio of materials, the following practical corrugated pipe materials are selected to meet the following conditions: good plasticity, sufficient hardness and strength, high elasticity, tensile strength, and fatigue strength. Generally, stainless steel materials such as 304, 316, and 316L are recommended. Although the connecting parts of the corrugated pipe structure also have flexible functions, the flexibility effect of rigid materials is not as obvious as that of non-metallic materials, and non-metallic materials are cheaper. Therefore, when the lateral force is not large, a floating device made entirely of metal materials can be selected.

[0007] The inner end (61), outer end (62), and intermediate connection (63) of the floating device (6) are made of non-metallic materials. The floating device is made entirely of non-metallic materials, such as polyurethane, rubber, nylon, polytetrafluoroethylene, and fiber. Although they have good elasticity, the wear resistance and fatigue strength of non-metallic materials are lower than those of metallic materials, and they are also more prone to aging.

[0008] The inner end 61 and outer end 62 of the floating device (6) are made of metal, while the middle connection 63 is made of non-metal. The inner end 61 is connected to the cylinder, and the outer end 62 is in contact with the external connecting parts. The inner and outer ends are made of metal, which has better rigidity and strength and is less likely to allow particles to enter. It can effectively resist the problem of accelerated aging of the sealing ring due to long-term uneven wear and cylinder leakage. The middle part is made of non-metal, which has good flexibility and can completely solve the problem of the cylinder being affected by lateral force. The sealing ring will have a longer service life if there is no lateral force inside the floating device. Therefore, the floating device can solve the problems of external leakage, external pollution, no lateral force, confidential sealing, and protection of the piston rod.

[0009] The inner end 61 and outer end 62 are made of stainless steel and carbon steel, while the intermediate connection 63 is mainly made of rubber. The intermediate connection contains three layers of rubber with a rubber content ranging from 65% to 80%. It is suitable for internal pressures not exceeding 32 MPa and external pressures not exceeding 25 MPa, providing absolute sealing and pressure resistance without sacrificing flexibility. The intermediate connection 63 is resistant to acid, alkali, and sulfur corrosion, internal pressure, external pressure, oil, and water, while also possessing good flexibility.

[0010] The length ratio of the inner end 61: intermediate connection 63: outer end 62 is 1:4:2 to 1:12:2. The preferred ratio is 1:7:2. The larger the proportion of the intermediate connection 63, the better the effect. Exceeding this range, the economy deteriorates. The total length of the flexible parts should not exceed the exposed length of the piston rod.

[0011] The beneficial technical effects of the present invention are as follows: the piston seal is installed on the piston and contacts the cylinder to form a cylinder seal; the piston is connected to the piston rod, and the hydraulic energy of the piston is released to the outside through the piston rod to form the thrust or pull force executed by the oil cylinder; the cylinder is fixedly connected to the inner end of the floating device; the inner end of the floating device is provided with a support; the outer end is provided with a floating seal and a support; the support and the floating seal contact the piston rod to form a rod seal.

[0012] This invention uses a floating device to completely solve the problem of the piston rod being affected by lateral force. The lateral force under the working condition will not change, but the floating seal inside the floating device has no lateral force. By extending the seal life, the service life of the hydraulic cylinder is extended. The floating device and the floating seal will swing along with the piston rod as it is deformed by the lateral force. The contact point between the piston rod and the floating seal always remains coaxial with the floating seal without any wear. Attached Figure Description

[0013] Figure 1 is a schematic diagram of the hydraulic cylinder structure of the present invention.

[0014] Figure 2 shows the state of the hydraulic cylinder of the present invention under lateral force.

[0015] Figure 3 shows the second state of the hydraulic cylinder under lateral force according to the present invention.

[0016] Figure 4 is a schematic diagram of the floating device structure of the present invention. Detailed Implementation

[0017] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the novel embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention. Example 1

[0018] A floating sealing cylinder includes a cylinder barrel 1, a piston 2, a piston seal 3, a piston rod 4, a support 5, a floating device 6, and a floating seal 7. The piston 2 and piston rod 4 are disposed inside the cylinder barrel 1. The piston 2 is sealed to the inner wall of the cylinder barrel 1 by the piston seal 3. The tail end of the cylinder barrel 1 is connected to the floating device 6. The support 5 is provided between the floating device 6 and the piston rod 4. The floating device 6 and the piston rod 4 are sealed by the floating seal 7. The cylinder 1 is in contact with the piston seal 3 on the piston 2. The piston 2 is connected to the piston rod 4. The liquid acts on both ends of the piston to form hydraulic energy. The entire cylinder transmits the hydraulic energy received by the piston 1 to the outside through the piston rod 4 to complete the action of the cylinder actuator. The cylinder 1 is connected to the floating device 6. The floating device 6 is characterized by its inner end 61 serving as a guide, support, and fixation, and its outer end 62 serving as a guide, support, float, and seal. The support 5 built into the floating device 6 is in contact with the piston rod 4. The inner diameter of the floating device 6 is larger than the outer diameter of the piston rod, with a gap of 1-5mm. Combined with the piston 1, it provides two fixed points to keep the piston rod 4 coaxial during movement. The cylinder is generally a reciprocating cylinder. Other types of cylinders, such as rotary swing cylinders, and rod-sealed products are affected by lateral forces, which can be solved by this patent.

[0019] The floating device 6 includes an inner end 61, an outer end 62, and an intermediate connection 63. The inner end 61 is connected to the cylinder 1, and the connection method can be threaded, bolted, or flanged. The inner end 61 is provided with a support 5 that contacts the piston rod 4. The inner end is a fixed rigid connection, which provides support and guidance for the piston rod 4. The outer end 62 of the floating device 6 is provided with a floating seal 7 and a support 5. The floating seal 7 plays a sealing role, which can prevent leakage of the internal rod cavity and the entry of external contaminants. The support 5 at the outer end of the floating device 6 provides support and prevents rod scratches. The intermediate connection 63 is a flexible component. As the piston rod deforms under force, it provides absolute sealing and pressure resistance without losing flexibility.

[0020] The floating device 6 designed in this invention is suitable for internal pressure not exceeding 32MPa and external pressure not exceeding 25MPa, with an adhesive content ranging from 65% to 80%. The overall distribution consists of three layers of adhesive, with interlaced curtains and a spirally woven frame sandwiched in between, providing absolute sealing and pressure resistance without losing flexibility. The floating device (6) can be made of all-metal, all-non-metal, or a combination of metal and non-metal. As long as it can achieve the sealing of one end and the floating end, it can realize the content described in this patent. If the working conditions are relatively corrosive, it is recommended to choose all-non-metal materials, which have better chemical corrosion resistance. If the working conditions require a longer service life, it is recommended to choose a combination of metal and non-metal, which has better overall performance. The structural form mainly depends on the working pressure. When the pressure is below 5MPa, it is recommended to choose one-piece molding, which has a relatively low production cycle and finished product. When the pressure is above 5MPa (including 5MPa), it is recommended to choose assembly process, which has a relatively high pressure and requires better stability. The floating seal 7 needs to be considered in conjunction with the working conditions.

[0021] The floating device 6 is made of a combination of metal and non-metal. The inner end 61 and the outer end 62 of the floating device 6 are made of metal, while the middle connection 63 is made of non-metal. The materials are flexible materials, such as plastics (polyethylene, polypropylene, polyurethane, etc.), rubber, and composite materials.

[0022] When the movement of the cylinder extends or retracts as shown in Figure 2, the exposed part of the piston rod 4 is subjected to lateral force F and undergoes bending deformation. The intermediate connection 63 of the floating device 6 deforms, and the floating seal 7 inside the outer end 62 causes the floating device 6 to bend and deform together with the piston rod 4. At this time, the floating seal 7 inside the outer end 62 of the floating device 6 remains coaxial with the piston rod 4. The floating seal 7 is not affected by the lateral force F. The value range of the lateral force F should not exceed the magnitude of the lateral force that the piston rod can withstand.

[0023] When the movement of the cylinder extends or retracts as shown in Figure 3, the exposed part of the piston rod 4 is subjected to lateral force F and undergoes bending deformation. Under the action of the floating seal 7 inside the outer end of the floating device 6, the floating device 6 bends and deforms together with the piston rod 4. At this time, the floating seal 7 inside the outer end of the floating device 6 remains coaxial with the piston rod 4, and the floating seal 7 is not affected by the lateral force F.

[0024] The length ratio of the inner end 61, the intermediate connection 63, and the outer end 62 is 1:4:2.

[0025] First, a piston rod with a length of 3000mm and a diameter of 40mm was used as a case study for design. The set range was that the piston rod was fully extended, the cylinder was fixed, and the swing amplitude of the rod head was set to ±200mm. A 40mm long support was set on the inner side of the floating device, the inner end 61 was 50mm long, and a total of 6 seals were selected based on the working conditions. The outer end 62 was 100mm long, and the middle connection length was 200mm, with a ratio of 1:4:2. The total length of the floating device 6 was 350mm, and the designed piston rod length was 400mm. The installation dimensions and pipelines were each extended by 350mm. The effect can be further improved. The bending degree of the floating device is not enough. It is hoped that the bending radius can reach 150mm. The bending radius currently achieved is about 300mm. Example 2

[0026] The other structures are the same as in Embodiment 1, except that: the length ratio of the inner end 61: intermediate connection 63: outer end 62 is 1:12:2, the length of the intermediate connection 63 is 600mm, the total length of the inner end 61 is 50mm, the total length of the outer end 62 is 100mm, the ratio is 1:12:2, the total length of the floating device 6 is 750mm, the exposed length of the cylinder piston rod is designed to be 780mm, the intermediate connection is longer, the floating device has good curvature, the curvature can reach 200-300mm, although the curvature is good, the installation height needs to be increased by 750mm, which is too high and inconvenient to install, and the economic benefits are not good. Example 3

[0027] The other structures are the same as in Embodiment 1, except that when the length ratio of the inner end 61: intermediate connection 63: outer end 62 is 1:7:2, the length of the intermediate connection 63 is 350mm, the total length of the inner end 61 is 50mm, the total length of the outer end 62 is 100mm, the total length of the floating device is 500mm, the exposed piston rod is 520mm, the intermediate connection is a flexible part, the deformation effect is good, the bending degree can reach 300mm, the height is moderate, and the overall cost is moderate.

[0028] In summary, the optimal ratio is 1:7:2, which provides the best overall effect. This range is a reference value provided for comprehensive design considerations. The intermediate connection 63 is made of multiple materials, and the selected material is composite rubber, which has the characteristics of being resistant to acid, alkali and sulfur corrosion, internal pressure, external pressure, oil and water, and also has good flexibility. Eliminating radial force can increase the service life of the hydraulic cylinder by 3 years.

[0029] In existing technologies, the support distance between the piston seal and the rod seal changes when the piston rod extends or retracts, causing changes in the overall rigidity of the cylinder, its resistance to lateral forces, and its stability. A larger distance between the two points results in better rigidity, and vice versa. This process is unavoidable. Lateral forces are determined by the operating conditions; if the operating conditions remain unchanged, the lateral forces also remain unchanged. Prolonged exposure to lateral forces can lead to severe uneven wear on the rod seal. Excessive wear can cause leakage from the rod seal, and the shortened seal life directly affects the cylinder's service life. This invention uses a floating device to completely solve the problem of lateral forces affecting the rod seal. The lateral forces under operating conditions remain unchanged, but the floating seal within the floating device is not subject to lateral forces. By extending the seal life, the cylinder's service life is extended. The floating device and floating seal oscillate as the piston rod deforms under lateral forces, ensuring that the contact point between the piston rod and the floating seal remains coaxial and free from uneven wear. This application can be applied to hydraulic cylinders subjected to severe lateral wear due to lateral forces. Long-term lateral wear accelerates the aging of the seal ring, leading to rapid cylinder leakage. In environments with external pressure or pollution such as sand and dust, the seal is subjected to lateral forces, resulting in excessive compression on one side and a large gap between the seal and the piston rod on the opposite side. External particles can enter and scratch the piston rod, thereby damaging the seal ring. The hydraulic cylinder will soon fail and leak externally. This floating device can completely solve the problem of lateral forces affecting the hydraulic cylinder. The seal ring is free from lateral forces within the floating device, thus extending its service life. Therefore, the floating device can solve the problems of external leakage, external pollution, no lateral forces, secure sealing, and protection of the piston rod.

[0030]

Claims

1. A floating sealing cylinder, comprising a cylinder barrel (1), a piston (2), a piston seal (3), a piston rod (4), a support (5), a floating device (6), and a floating seal (7), characterized in that: The cylinder (1) is equipped with a piston (2) and a piston rod (4). The piston (2) is sealed to the inner wall of the cylinder (1) by a piston seal (3). The tail end of the cylinder (1) is connected to a floating device (6). A support (5) is provided between the floating device (6) and the piston rod (4). The floating device (6) and the piston rod (4) are sealed by a floating seal (7).

2. A floating sealing cylinder according to claim 1, characterized in that: The floating device (6) includes an inner end (61), an outer end (62) and an intermediate connection (63). The inner end (61) is connected to the cylinder (1). The inner end (61) is provided with a support (5) that contacts the piston rod (4). The outer end (62) of the floating device (6) is provided with a floating seal (7) and a support (5).

3. A floating sealing cylinder according to claim 1, characterized in that: The inner end (61), outer end (62), and intermediate connection (63) of the floating device (6) are made of metal.

4. A floating sealing cylinder according to claim 1, characterized in that: The inner end (61), outer end (62), and intermediate connection (63) of the floating device (6) are made of non-metallic materials.

5. A floating sealing cylinder according to claim 1, characterized in that: The inner end (61) and outer end (62) of the floating device (6) are made of metal, and the middle connection (63) is made of non-metal.

6. A floating sealing cylinder according to claim 5, characterized in that: The inner end (61) and outer end (62) are made of stainless steel and carbon steel, and the intermediate connection (63) is mainly made of rubber. The intermediate connection contains three layers of rubber with a rubber content range of 65% to 80%. It is suitable for internal pressure not exceeding 32MPa and external pressure not exceeding 25MPa.

7. A floating sealing cylinder according to claim 5, characterized in that: The length ratio of the inner end (61): intermediate connection (63): outer end (62) is 1:4:2~1:12:

2.

8. A floating sealing cylinder according to claim 7, characterized in that: The length ratio of the inner end (61): intermediate connection (63): outer end (62) is 1:7:2.

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