A stepped sealing structure applied to a high-pressure large-diameter oil cylinder

Abstract

The utility model relates to the technical field of hydraulic pressure discloses a ladder sealing structure for high pressure large diameter oil cylinder, including cylinder and flange, the upper end of flange outer wall is connected with the lower end of cylinder inner wall, the cylinder inner wall is provided with the piston, the upper end of flane inner wall is equipped with the dustproof ring, the one end of flange inner wall is away from the first guide zone and the second guide zone of flange center, the one end of flange inner wall is equipped with the first sealing element and the second sealing element close to flange center, the middle part of flange inner wall is equipped with transition chamber, the lower part of cylinder inner wall is equipped with the rod cavity, the both sides of cylinder lower end are equipped with the first throttle, in the utility model, through first sealing element and second sealing element constitute main - auxiliary two - level sealing system, has improved the sealing reliability, and the transition chamber between both is as buffer zone, has protected sealing element and hydraulic system to prolong the equipment life and ensure the smooth operation.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic technology, and in particular to a stepped sealing structure for use in high-pressure, large-diameter hydraulic cylinders. Background Technology

[0002] In high-pressure, large-diameter hydraulic cylinder applications, the seal dimensions are required to be large and the hydraulic oil pressure is high. In order to achieve the ideal sealing effect, the machining accuracy is often improved and the tolerance range is reduced. Excessive tightness in the fit tolerance will reduce the clearance between moving parts, causing the seal to bear huge frictional resistance during operation. This not only increases the energy consumption of the cylinder's start-up and operation, but also leads to rapid wear of the seal and shortens its service life. Currently, another common engineering practice is to use two or three seals arranged in series in order to build multiple leak-proof barriers.

[0003] Under normal operating conditions, only the first sealing element of the existing sealing method is actually involved in pressure sealing. The high-pressure oil is effectively blocked by the first seal and cannot reach the chamber where the subsequent sealing elements are located, which makes it difficult to solve the reliability problem of high-pressure sealing.

[0004] Therefore, those skilled in the art have provided a stepped sealing structure for use in high-pressure, large-diameter hydraulic cylinders to solve the problems mentioned in the background art. Utility Model Content

[0005] The purpose of this invention is to address the shortcomings of existing technologies and provide a stepped sealing structure for high-pressure, large-diameter hydraulic cylinders. The first and second sealing elements form a main-auxiliary dual-stage sealing system, which improves sealing reliability. The transition cavity between the two elements acts as a buffer zone, protecting the sealing elements and the hydraulic system, thereby extending equipment life and ensuring smooth operation.

[0006] To achieve the above objectives, this utility model provides the following technical solution: A stepped sealing structure for high-pressure, large-diameter hydraulic cylinders includes a cylinder barrel and a flange. The upper end of the outer wall of the flange is connected to the lower end of the inner wall of the cylinder barrel. A piston is disposed on the inner wall of the cylinder barrel. A dustproof ring is fitted on the upper end of the inner wall of the flange. A first guide band and a second guide band are disposed on the end of the inner wall of the flange away from the center of the flange. A first sealing element and a second sealing element are fitted on the end of the inner wall of the flange close to the center of the flange. A transition cavity is opened in the middle of the inner wall of the flange. A rod cavity is opened in the lower part of the inner wall of the cylinder barrel. A first throttling orifice is opened on both sides of the lower end of the cylinder barrel. A second throttling orifice is opened in the middle of one side of the inner wall of the flange. The above technical solution, through the cooperation of the first sealing element and the second sealing ring, constitutes a main-auxiliary dual-stage sealing system, which improves the reliability of the system. The transition cavity formed by the design creates a closed buffer zone. When there is a very small amount of leakage from the main seal, the oil will be temporarily stored in the transition cavity instead of immediately leaking to the outside, thus protecting the seal and the hydraulic system, extending the equipment life, and ensuring smooth operation.

[0007] Furthermore, the rod end pressure is defined as P, and the transition chamber pressure between the first seal and the second seal is designed as P1; The above technical solution establishes an intermediate pressure level between two seals through a controlled transition cavity, thereby achieving pressure grading and reducing the pressure on a single seal.

[0008] Furthermore, the second throttle orifice is connected to an oil tank with a pressure of PL and PL=0; The above technical solution ensures that the pressure on the outside of the second seal is stable and known, and provides the system with a final discharge channel for leaked oil.

[0009] Furthermore, high-pressure oil with pressure P is introduced into the rod chamber, and a suitable first throttle orifice and a second throttle orifice are selected according to the Huygens bridge circuit, so that P1 = 1 / 2P; The above technical solution utilizes the principle of hydraulic bridge circuits to provide an active and controlled pressure regulation rather than a passive response. This pressure value provides a precise guarantee for the balanced distribution of pressure difference between the two subsequent seals.

[0010] Furthermore, the pressure difference across the first seal is ΔP = P - P1 = 1 / 2P, and the pressure difference across the second seal is ΔP = -P1 - PL = 1 / 2P. Through the above technical solution, the two seals participate in the pressure sealing work simultaneously and equally, changing the traditional design mode of "one working and one on standby".

[0011] Furthermore, the sides of both the first and second seals near the center of the cylinder are in contact with the outer wall of the piston; The above technical solution establishes the pressure difference in actual operation, achieving a reliable stepped sealing effect.

[0012] This utility model has the following beneficial effects: 1. The present invention proposes a stepped sealing structure for high-pressure large-diameter hydraulic cylinders. Through the cooperation of the first sealing element and the second sealing ring element, a main-auxiliary dual-stage sealing system is formed, which improves the reliability of the system. The set transition cavity forms a closed buffer zone. When there is a very small amount of leakage in the main seal, the oil will be temporarily stored in the transition cavity instead of immediately leaking to the outside, protecting the seal and hydraulic system, extending the service life of the equipment, and ensuring smooth operation. Attached Figure Description

[0013] Figure 1 This is an isometric view of a stepped sealing structure for use in a high-pressure, large-diameter hydraulic cylinder, as proposed in this utility model. Figure 2 This is a side sectional view of a stepped sealing structure for use in a high-pressure, large-diameter hydraulic cylinder, as proposed in this utility model. Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0014] Explanation of reference numerals in the attached figures: 1. Cylinder; 2. Piston; 3. Flange; 4. Dust seal; 5. Second guide band; 6. Second seal; 7. Transition chamber; 8. First seal; 9. First guide band; 10. Rod chamber; 11. First throttle orifice; 12. Second throttle orifice. Detailed Implementation

[0015] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of specific embodiments. Obviously, the described specific embodiments are only a part of the specific embodiments of the present invention, and not all of them. Based on the specific embodiments of the present invention, all other specific embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] Reference Figure 1 , Figure 2 and Figure 3 This utility model provides a specific implementation method: A stepped sealing structure for high-pressure large-diameter hydraulic cylinders includes a cylinder barrel 1 and a flange 3. The upper end of the outer wall of the flange 3 is connected to the lower end of the inner wall of the cylinder barrel 1. A piston 2 is provided on the inner wall of the cylinder barrel 1. A dustproof ring 4 is fitted on the upper end of the inner wall of the flange 3. A first guide band 9 and a second guide band 5 are provided on the end of the inner wall of the flange 3 away from the center of the flange 3. A first sealing element 8 and a second sealing element 6 are fitted on the end of the inner wall of the flange 3 close to the center of the flange 3. A transition cavity 7 is opened in the middle of the inner wall of the flange 3. A rod cavity 10 is opened in the lower part of the inner wall of the cylinder barrel 1. A first throttling orifice 11 is opened on both sides of the lower end of the cylinder barrel 1. A second throttling orifice 12 is opened in the middle of one side of the inner wall of the flange 3. The cooperation of the first seal 8 and the second sealing ring forms a main-auxiliary dual-stage sealing system, which improves the reliability of the system. The transition chamber 7 forms a closed buffer zone. When there is a very small amount of leakage in the main seal, the oil will be temporarily stored in the transition chamber 7 instead of leaking to the outside immediately, thus protecting the seal and hydraulic system, extending the equipment life, and ensuring smooth operation.

[0017] Reference Figure 2 and Figure 3 The pressure at the rod chamber 10 is defined as P. A transition chamber 7 with pressure P1 is designed between the first seal 8 and the second seal 6. Through a controlled transition chamber 7, an intermediate pressure level is established between the two seals, achieving pressure grading and reducing the pressure on a single seal. The second throttle port 12 is connected to an oil tank with a pressure PL, where PL=0, ensuring that the pressure on the outer side of the second seal 6 is stable and known, and providing a final discharge channel for leaked oil. High-pressure oil with pressure P is introduced into the rod chamber 10. Appropriate first and second throttle ports 11 and 12 are selected according to the Huygens bridge circuit, such that P1=1 / 2P, through a hydraulic bridge. The principle of the circuit makes it an active and controlled pressure regulation rather than a passive response. This pressure value provides a precise guarantee for the balanced distribution of pressure difference between the two subsequent seals. The pressure difference between the two sides of the first seal 8 is ΔP = P - P1 = 1 / 2P, and the pressure difference between the two sides of the second seal 6 is ΔP = -P1 - PL = 1 / 2P. The two seals participate in the pressure-bearing sealing work simultaneously and equally, changing the traditional design mode of "one working and one standby". The side of the first seal 8 and the second seal 6 near the center of the cylinder 1 are both in contact with the outer wall of the piston 2. The pressure difference ΔP1 and ΔP2 established in actual operation achieve a reliable stepped sealing effect.

[0018] Working principle: When the hydraulic cylinder is engaged, high-pressure oil at pressure P is introduced into the rod chamber 10, forming the system's highest working pressure. This high-pressure oil is supplied to the transition chamber 7 through the first throttle port 11. Simultaneously, the oil in the transition chamber 7 can also flow back to the oil tank through the second throttle port 12 (oil tank pressure PL≈0). These two throttle ports together form a pressure regulating circuit, precisely controlling the pressure in the transition chamber 7 and stabilizing it at P1 = 1 / 2. At the level of P, under this pressure distribution, the left side (rod chamber 10 side) of the first seal 8 bears pressure P, and the right side (transition chamber 7 side) bears pressure P1. Therefore, the pressure difference it bears is ΔP1=P-P1=1 / 2P. The left side (transition chamber 7 side) of the second seal 6 bears pressure P1, and the right side (tank side) bears pressure that can be considered as 0. Therefore, its pressure difference is ΔP2=P1-PL=1 / 2P. Through this mechanism, the sealing system that originally required a single sealing structure to bear the entire pressure P is transformed into a system in which two seals work together. Each seal only needs to bear half of the system pressure. The two seals simultaneously and actively play a sealing role, reliably sealing the high-pressure oil inside the system.

[0019] The following points should be noted in this article: 1. The accompanying drawings of the embodiments disclosed herein only relate to the structures involved in the embodiments disclosed herein; other structures can be referred to in general design.

[0020] 2. Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0021] Finally, it should be noted that the above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing specific embodiments, those skilled in the art can still modify the technical solutions described in the foregoing specific embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., 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 stepped sealing structure for use in high-pressure, large-diameter hydraulic cylinders, comprising a cylinder barrel (1) and a flange (3), characterized in that: The upper end of the outer wall of the flange (3) is connected to the lower end of the inner wall of the cylinder (1). The inner wall of the cylinder (1) is provided with a piston (2). The upper end of the inner wall of the flange (3) is fitted with a dustproof ring (4). The inner wall of the flange (3) is provided with a first guide band (9) and a second guide band (5) at one end away from the center of the flange (3). The inner wall of the flange (3) is fitted with a first seal (8) and a second seal (6) at one end near the center of the flange (3). A transition cavity (7) is opened in the middle of the inner wall of the flange (3). A rod cavity (10) is opened in the lower part of the inner wall of the cylinder (1). A first throttling orifice (11) is opened on both sides of the lower end of the cylinder (1). A second throttling orifice (12) is opened in the middle of one side of the inner wall of the flange (3).

2. The stepped sealing structure for use in high-pressure large-diameter hydraulic cylinders according to claim 1, characterized in that: The pressure at the end of the rod chamber (10) is defined as P, and the pressure of the transition chamber between the first seal (8) and the second seal (6) is designed as P1.

3. The stepped sealing structure for use in high-pressure large-diameter hydraulic cylinders according to claim 1, characterized in that: The second throttle port (12) is connected to an oil tank with an oil tank pressure PL and PL=0.

4. The stepped sealing structure for use in high-pressure large-diameter hydraulic cylinders according to claim 1, characterized in that: The rod chamber (10) is supplied with high-pressure oil at pressure P. The appropriate first throttle port (11) and second throttle port (12) are selected according to the Huygens bridge circuit so that P1 = 1 / 2P.

5. A stepped sealing structure for use in high-pressure large-diameter hydraulic cylinders according to claim 1, characterized in that: The pressure difference between the two sides of the first seal (8) is ΔP = P - P1 = 1 / 2P, and the pressure difference between the two sides of the second seal (6) is ΔP = -P1 - PL = 1 / 2P.

6. The stepped sealing structure for use in high-pressure large-diameter hydraulic cylinders according to claim 1, characterized in that: The first seal (8) and the second seal (6) are both in contact with the outer wall of the piston (2) on the side near the center of the cylinder (1).

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