Pressure self-protection type hydraulic cylinder

Abstract

The pressure self-protection type hydraulic cylinder comprises an upper end cover and a lower end cover, a piston rod penetrates through the upper end cover in a sealing mode, two buffering devices are symmetrically and fixedly installed on one side of the upper end cover and one side of the lower end cover, each buffering device comprises a telescopic rod, the telescopic rods are fixedly installed on one side of the upper end cover, and a buffering pad is fixedly installed at one end of each telescopic rod. The outer wall of the telescopic rod is sleeved with a buffer spring, one end of the buffer spring is fixedly installed on one side of the upper end cover, the other side of the buffer spring is fixedly connected with a buffer pad, a supporting rod is fixedly installed on one side of the upper end cover, the supporting rod is fixedly installed on one side of the upper end cover, and the length of the buffer spring is larger than that of the supporting rod. According to the utility model, the moving piston is blocked through the buffer spring and the buffer pad, and is buffered through self deformation, so that the piston is prevented from being damaged by limiting through the end cover, and the service life of the device is prolonged.

Description

A pressure self-protection hydraulic cylinder Technical Field

[0001] This utility model relates to the field of hydraulic cylinder technology, and in particular to a pressure self-protection hydraulic cylinder. Background Technology

[0002] A hydraulic cylinder is a device that converts hydraulic energy into mechanical energy. It is mainly used to achieve linear reciprocating motion or oscillating motion. It achieves mechanical motion through the transmission of liquid pressure. The input is the pressure and flow rate of hydraulic oil, and the output is the linear motion speed and force of the piston. It is mainly composed of components such as cylinder body, piston, piston rod, seals, and end caps. The piston moves under pressure and transmits the motion to the external load through the piston rod.

[0003] According to the search, Chinese patent CN201891692U discloses that the utility model sets two overflow structures in opposite directions on the piston of the hydraulic cylinder, which can not only ensure that the hydraulic cylinder can effectively overflow when the pressure setting value is exceeded, thus ensuring the safety of the hydraulic cylinder, but also ensure that the overflow pressure cannot be arbitrarily adjusted, thus effectively ensuring the service life of the hydraulic cylinder.

[0004] However, in the aforementioned patent, the piston is in a high-speed motion state before pressure relief. After pressure relief, it will continue to move a distance due to inertia until the system pressure is rebalanced or blocked by the end cap. If it passes through the end cap for a long time, the piston will be damaged, affecting the service life of the device.

[0005] Therefore, this invention proposes a pressure self-protection hydraulic cylinder. Summary of the Invention

[0006] The technical problem to be solved: Before the pressure is released, the piston is in a state of high-speed movement. After the pressure is released, it will continue to move a distance due to inertia until the system pressure is rebalanced or blocked by the end cap. If it passes through the end cap for a long time, the piston may be damaged, affecting the service life of the device.

[0007] To achieve the above objectives, this utility model proposes a pressure self-protection hydraulic cylinder, including a cylinder body and a piston fitted inside the cylinder body cavity. A piston rod is installed at one end of the piston, and an upper end cover and a lower end cover are fixedly installed on both sides of the cylinder body. The piston rod seals through the upper end cover. The feature is that two buffer devices are symmetrically fixedly installed on one side of the upper end cover and the lower end cover.

[0008] The buffer device includes a telescopic rod, which is fixedly installed on one side of the upper cover. A buffer pad is fixedly installed at one end of the telescopic rod. A buffer spring is sleeved on the outer wall of the telescopic rod. One end of the buffer spring is fixedly installed on one side of the upper cover, and the other end of the buffer spring is fixedly connected to the buffer pad. A support rod is fixedly installed on one side of the upper cover. The length of the buffer spring is greater than the length of the support rod.

[0009] In one example, the piston has two overflow structures facing opposite directions. The two ends of the overflow structures are connected to the working chambers on both sides of the piston. The overflow structure includes three inner holes of different sizes on the piston. The two inner holes of different sizes are connected to the working chambers on both sides of the piston. A pressure regulating valve seat with a central through hole is fixedly installed in the cavity of the large inner hole. A connecting plate is fixedly installed on one side of the pressure regulating valve seat. A pressure regulating spring is fixedly installed on one side of the connecting plate. A truncated cone base cylinder that can seal the middle inner hole is fixedly installed on one side of the pressure regulating spring. A Gleic ring is fixedly fitted on the outer wall of the connection between the truncated cone base and the cylinder.

[0010] In one example, a telescopic rod is fixedly installed on one side of the connecting plate. The telescopic rod is sleeved inside the pressure regulating spring, and one end of the telescopic rod is connected to one side of the cylinder of the frustum base.

[0011] In one example, the position of the support rod matches the position of the small inner hole, allowing the support rod to move within the small inner hole.

[0012] In one example, the diameter of the support rod is smaller than the diameter of the small inner hole.

[0013] In one example, the adjusting spring is made of alloy steel.

[0014] In one example, the inner wall of the cylinder is equipped with multiple pressure sensors.

[0015] The pressure self-protection hydraulic cylinder proposed in this utility model has the following beneficial effects:

[0016] 1. In this utility model, the moving piston is blocked by a buffer spring and a buffer pad, buffered by its own deformation, and limited by a telescopic rod, thus avoiding damage to the piston caused by limiting it by the end cap, thereby improving the service life of the device.

[0017] 2. In this utility model, when the pressure is too high and the buffering force of the buffer spring and buffer pad is insufficient for the piston to continue moving, the support rod moves in the small inner hole to move the cylinder of the frustum base out of the middle inner hole, thereby relieving pressure for the second time, further reducing the force of piston movement, and thus reducing the damage to the piston. Attached Figure Description

[0018] Figure 1 is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 is a schematic diagram of the lower cross-sectional structure of this utility model;

[0020] Figure 3 is an enlarged view of point A in Figure 2;

[0021] Figure 4 is a schematic diagram of the cylindrical structure of the frustum base of this utility model;

[0022] Figure 5 is a schematic diagram of the right sectional view of this utility model.

[0023] The attached figures are labeled as follows:

[0024] 1. Cylinder body; 2. Piston; 3. Piston rod; 4. Upper end cover; 5. Buffer device; 51. Buffer pad; 52. Buffer spring; 53. Support rod; 6. Overflow structure; 61. Pressure regulating valve seat; 62. Connecting plate; 63. Pressure regulating spring; 64. Frustum base cylinder. Detailed Implementation

[0025] To more clearly illustrate the overall concept of this utility model, a detailed description will be provided below with reference to the accompanying drawings.

[0026] In the description of this utility model, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0027] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0029] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "a solution," "some solutions," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that solution or example is included in at least one solution or example of this invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same solution or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more solutions or examples.

[0030] As shown in Figures 1-5, an embodiment of this utility model proposes a pressure self-protection hydraulic cylinder, which includes a cylinder body 1. The cylinder body 1 is provided with a first oil guide port and a second oil guide port. Filters are installed on the first oil guide port and the second oil guide port to filter oil impurities. High-pressure oil is introduced from the first oil guide port into the rodless chamber by a hydraulic pump, which squeezes one side of the piston 2, causing the piston 2 to move into the rod chamber. The oil in the rod chamber exits from the second oil guide port and is pumped into the oil tank by the hydraulic pump. This drives the piston rod 3, which is fixedly installed on the other side of the piston 2, to move. The piston rod 3 moves in the upper end cover 4, which is fixedly installed on one side of the cylinder body 1. In order to ensure that the piston rod 3 does not leak oil or allow dust to enter the hydraulic cylinder when it moves, a buffer ring, a sealing ring, a support ring, and a dustproof ring are installed sequentially from the inside to the outside at the connection part of the upper end cover 4.

[0031] To ensure the hydraulic cylinder operates within the pressure range set at the factory and to extend its service life, pressure sensors are installed on the inner walls of the rod-side and rodless-side chambers of the hydraulic cylinder to detect the pressure. When the pressure exceeds the factory-set value, pressure is released through two overflow structures 6 installed on the piston 2 in opposite directions. The two ends of each overflow structure 6 communicate with the working chambers on both sides of the piston 2. Each overflow structure 6 includes three inner holes of different sizes on the piston 2. The two smaller holes communicate with the working chambers on both sides of the piston 2. A pressure regulating valve seat 61 with a central through-hole is fixedly installed inside the cavity of the larger inner hole. A connecting plate 62 is fixedly installed on one side of the pressure regulating valve seat 61, allowing oil to flow from both the upper and lower sides of the connecting plate 62. A pressure regulating spring 63 is fixedly installed on one side, and a frustum base cylinder 64 that can seal the inner hole is fixedly installed on one side of the pressure regulating spring 63. A Glyd ring 7 is fixedly sleeved on the outer wall of the connection between the frustum base and the cylinder. The frustum base protects the Glyd ring 7 and prevents it from detaching under high pressure. The cylinder on the frustum base cylinder 64 performs a preliminary seal on the small inner hole, and the Glyd ring 7 performs a second seal on the inner hole, improving the sealing performance of the device. The Glyd ring 7 is composed of a synthetic rubber O-ring and a square sealing ring filled with polytetrafluoroethylene (PTFE). The O-ring provides elasticity compensation and is suitable for high pressure conditions. The standard pressure resistance is 40MPa, and it can reach 60MPa after adding a special retaining ring (such as nylon or polyoxymethylene). The sealing is performed by the Glyd ring 7.

[0032] When the pressure value exceeds the factory-set value, the pressure will push the cylinder 64 of the frustum base to move through the small inner hole, causing the cylinder 64 of the frustum base to move out of the middle inner hole, causing the pressure regulating spring 63 to deform and accumulate elastic potential energy. At the same time, the high-pressure oil will enter the rod chamber sequentially through the small inner hole, the middle inner hole and the central through hole of the pressure regulating valve seat 61, which plays a role in relieving pressure and preventing the hydraulic cylinder from being in a high-pressure state for a long time, thus affecting the service life of the hydraulic cylinder.

[0033] To ensure that the height of the cylinder 64 of the frustum base does not move, a telescopic rod is fixedly installed on one side of the connecting plate 62. The telescopic rod is located inside the pressure regulating spring 63, and one end of the telescopic rod is connected to one side of the cylinder 64 of the frustum base. The telescopic rod is used for limiting the position.

[0034] During the depressurization process, the piston 2 is in a high-speed motion state before depressurization. During depressurization, it will continue to move a distance due to inertia until the system pressure is rebalanced or blocked by the end cap. If it passes through the end cap for a long time, the piston 2 may be damaged, affecting the service life of the device. Two buffer devices 5 are symmetrically installed on one side of the upper end cap 4 and the lower end cap of the cylinder body 1. The buffer device 5 includes a telescopic rod, which is fixedly installed on one side of the upper end cap. A buffer pad 51 is fixedly installed at one end of the telescopic rod, and a buffer spring 52 is sleeved on the outer wall of the telescopic rod. One end of the buffer spring 52 is fixedly installed on one side of the upper end cap 4, and the other side of the buffer spring 52 is fixedly connected to the buffer pad 51. A support rod 53 is fixedly installed on one side of the upper end cap 4. The length of the buffer spring 52 is greater than the length of the support rod 53. When the piston 2 contacts the buffer pad 51, the movement speed of the piston 2 is reduced by the deformation of the buffer pad 51 and the buffer spring 52 until the piston 2 stops moving.

[0035] When the pressure is too high, the piston 2 continues to move even when buffered by the buffer spring, so it is necessary to continue to release pressure. By setting the position of the support rod 53 to match the position of the small inner hole, and at the same time, the diameter of the support rod 53 is smaller than the diameter of the small inner hole, the support rod 53 can move in the small inner hole, thereby moving the cylinder 64 of the frustum base out of the middle inner hole. A wear-resistant coating or self-lubricating material is added between the support rod 53 and the small inner hole to reduce the energy loss and wear risk caused by friction, so that the high-pressure oil can enter the rod chamber in sequence through the central through hole, the middle inner hole and the small inner hole of the pressure regulating valve seat 61, which can accelerate the pressure release. In order to ensure the pressure release speed, the support rod is provided with evenly arranged through holes for the high-pressure oil to flow from the rodless chamber to the rod chamber, further reducing the force of piston 2 movement.

[0036] When piston 2 stops moving, the cylinder 64 of the frustum base, under the action of the elastic potential energy accumulated by the pressure regulating spring 63 and the limit of the telescopic rod, re-enters the inner hole and is sealed by the girder ring 7.

[0037] A pressure sensor is installed on one side of the support rod 53. When the pressure detected by the pressure sensor reaches the preset value for secondary pressure relief, it means that secondary pressure relief has been performed. After the piston rod 3 has finished working, in order to seal the inner hole again by the other frustum base cylinder 64, high-pressure oil needs to be introduced from the second oil guide port through the hydraulic pump to drive the piston 2 from the rod chamber to the rodless chamber. When the piston 2 moves a certain distance, the support rod 53 has been removed from the inner hole. At this time, the operation of the hydraulic pump is stopped. The elastic potential energy stored in the pressure regulating spring 63 is used to bounce the frustum base cylinder 64 into the inner hole. The inner hole is resealed by the grid ring 7 on the frustum base cylinder 64, and then the operation continues.

[0038] To improve the service life of the pressure regulating spring 63 and the buffer spring 52, alloy steel springs are used. Alloy steel springs are elastic elements made of alloy spring steel and have the functions of elastic support, shock absorption or energy storage. Compared with carbon spring steel, the addition of alloying elements significantly improves their strength, fatigue life and environmental resistance.

[0039] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0040] The above are merely embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this utility model should be included within the scope of the claims of this utility model.

Claims

1. A pressure self-protecting hydraulic cylinder, comprising a cylinder body (1) and a piston (2) fitted inside the cylinder body (1), wherein a piston rod (3) is installed at one end of the piston (2), and an upper end cover (4) and a lower end cover are fixedly installed on both sides of the cylinder body (1), wherein the piston rod (3) seals through the upper end cover (4), characterized in that, Two buffer devices (5) are symmetrically fixedly installed on one side of the upper end cover (4) and the lower end cover; the buffer device (5) includes a telescopic rod, which is fixedly installed on one side of the upper end cover (4), a buffer pad (51) is fixedly installed at one end of the telescopic rod, a buffer spring (52) is sleeved on the outer wall of the telescopic rod, one end of the buffer spring (52) is fixedly installed on one side of the upper end cover (4), the other side of the buffer spring (52) is fixedly connected to the buffer pad (51), a support rod (53) is fixedly installed on one side of the upper end cover (4), the support rod (53) is fixedly installed on one side of the upper end cover (4), and the length of the buffer spring (52) is greater than the length of the support rod (53).

2. The pressure self-protection hydraulic cylinder according to claim 1, characterized in that, Two overflow structures (6) with opposite directions are provided on the piston (2). The two ends of the overflow structure (6) are respectively connected to the working chambers on both sides of the piston (2). The overflow structure (6) includes three inner holes of large, medium and small on the piston (2). The two inner holes of large and small are the same as the working chambers on both sides of the piston (2). A pressure regulating valve seat (61) with a central through hole is fixedly installed in the cavity of the large inner hole. A connecting plate (62) is fixedly installed on one side of the pressure regulating valve seat (61). A pressure regulating spring (63) is fixedly installed on one side of the connecting plate (62). A frustum base cylinder (64) that can seal the central inner hole is fixedly installed on one side of the pressure regulating spring (63). A Glee ring (7) is fixedly sleeved on the outer wall of the connection between the frustum base and the cylinder.

3. A pressure self-protecting hydraulic cylinder according to claim 2, characterized in that, A telescopic rod is fixedly installed on one side of the connecting plate (62), the telescopic rod is sleeved inside the pressure regulating spring (63), and one end of the telescopic rod is connected to one side of the cylindrical column (64) of the frustum base.

4. A pressure self-protecting hydraulic cylinder according to claim 2, characterized in that, The position of the support rod (53) matches the position of the small inner hole, so that the support rod (53) can move in the small inner hole.

5. A pressure self-protecting hydraulic cylinder according to claim 2, characterized in that, The diameter of the support rod (53) is smaller than the diameter of the small inner hole.

6. A pressure self-protecting hydraulic cylinder according to claim 2, characterized in that, The pressure regulating spring (63) is made of alloy steel.

7. A pressure self-protecting hydraulic cylinder according to claim 1, characterized in that, The inner wall of the cylinder (1) is equipped with multiple pressure sensors.

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