CN110645225B

CN110645225B - High-pressure protection device for hydraulic cylinder

Info

Publication number: CN110645225B
Application number: CN201910939455.2A
Authority: CN
Inventors: 牛国贤; 苏晓岩; 付丙勤
Original assignee: Beijing Machinery Equipment Research Institute
Current assignee: Beijing Machinery Equipment Research Institute
Priority date: 2019-09-29
Filing date: 2019-09-29
Publication date: 2021-08-17
Anticipated expiration: 2039-09-29
Also published as: CN110645225A

Abstract

The invention relates to a high-pressure protection device of a hydraulic cylinder, relates to the technical field of hydraulic control, and solves the problems that an oil spilling protection device in the prior art has complicated pipelines and the position precision of the hydraulic cylinder after oil spilling is difficult to guarantee. The invention relates to a high-pressure protection device of a hydraulic cylinder, which comprises a valve body, a first piston, a second piston and a spring, wherein the first piston, the second piston and the spring are arranged in an inner cavity of the valve body; the spring is positioned between the first piston and the second piston; the outer ends of the first piston and the second piston are respectively communicated with a rodless cavity and a rod cavity of the hydraulic cylinder; when the pressure in the rodless cavity and the rod cavity overcomes the initial elasticity of the spring, the hydraulic oil pushes the first piston and the second piston to compress the spring, and the hydraulic oil flows into the inner cavity of the valve body. The hydraulic cylinder high-pressure protection device is simple in structure, can be directly installed on a hydraulic cylinder control valve block, saves an overflow valve and an oil overflow pipeline, and simplifies a hydraulic system; the unilateral deviation of the piston position in the hydraulic cylinder after oil drainage is not more than 1mm, and the position precision of the hydraulic cylinder is ensured.

Description

High-pressure protection device for hydraulic cylinder

Technical Field

The invention relates to the technical field of hydraulic control, in particular to a high-pressure protection device for a hydraulic cylinder.

Background

The hydraulic cylinder is one of main actuating mechanisms of a hydraulic system, and is widely applied to the fields of machine tool industry, metallurgical industry, automobile industry, light textile industry, engineering machinery, agricultural machinery and the like. In fields where precise control is required, such as the field where support and horizontal angular adjustment of the mechanism is achieved by means of hydraulic cylinders, the hydraulic cylinders need to be locked after they have been moved to a specified position.

At present, most hydraulic systems ensure the locking of a hydraulic cylinder through a hydraulic lock, as shown in fig. 1, when a hydraulic cylinder (200) moves to a designated position, a hydraulic pump stops supplying oil, the hydraulic lock (300) is closed, and two sides of a piston of the hydraulic cylinder form a closed cavity. When the ambient temperature rose, cause the hydraulic oil inflation, form the high pressure in the hydraulic cylinder seals holds the chamber, can destroy hydraulic line when serious.

In order to prevent the situation that the high pressure of the closed oil cavity of the hydraulic cylinder damages a hydraulic pipeline due to the temperature rise, the two oil cavities of the hydraulic cylinder are respectively connected with overflow valves, and as shown in fig. 2, when the pressure of the closed oil cavity exceeds the regulating pressure of the overflow valve (400), the overflow valve opens an oil overflow mode to protect a hydraulic system from being damaged.

The overflow valve is used for protecting the hydraulic cylinder, so that the hydraulic cylinder is not damaged by temperature rise and high pressure, and the mode is simple and easy to implement, but still has the following defects:

(1) an overflow pipeline needs to be independently arranged for an overflow valve, so that the pipeline of the hydraulic system is more complicated; (2) the overflow amount of the overflow valve is not controlled, so that the overflow amounts at the two ends of the hydraulic cylinder are unstable, and the single side of a piston in the hydraulic cylinder deviates by more than 10mm, so that the position precision of the hydraulic cylinder after temperature rise and oil overflow is difficult to ensure.

Disclosure of Invention

In view of the foregoing analysis, an embodiment of the present invention is directed to a high-pressure protection device for a hydraulic cylinder, which can solve at least one of the following technical problems: (1) the oil spilling protection device has complicated pipelines; (2) the position precision of the hydraulic cylinder after oil spilling is difficult to guarantee.

The embodiment of the invention provides a high-pressure protection device of a hydraulic cylinder, which comprises a valve body, a first piston, a second piston and a spring, wherein the first piston, the second piston and the spring are arranged in an inner cavity of the valve body; the spring is positioned between the first piston and the second piston; the outer ends of the first piston and the second piston are respectively communicated with a rodless cavity and a rod cavity of the hydraulic cylinder; when the pressure in the rodless cavity and the rod cavity overcomes the initial elasticity of the spring, the hydraulic oil pushes the first piston and the second piston to compress the spring, and the hydraulic oil flows to the inner cavity of the valve body.

Further, the action areas S of the first piston and the second piston₁₂、S₁₃The ratio of the effective area S to the effective area S of the rodless cavity and the rod cavity₂₁、S₂₂The proportion relation is as follows: s₁₂/S₁₃＝α*S₂₁/S₂₂，

Wherein the range of the adjustment coefficient alpha is 0.8-1.2.

Further, the inner cavity of the valve body comprises a first cavity and a second cavity, and the first piston and the second piston are respectively arranged in the first cavity and the second cavity;

a spring cavity for assembling the spring is formed between the first piston and the second piston;

the cross-sectional area of the spring chamber is equal to the cross-sectional area of the first chamber and greater than the cross-sectional area of the second chamber.

Further, the central axes of the first piston, the second piston and the spring are collinear;

the side surface of the first piston is matched with the side wall of the spring cavity;

the second piston comprises an end part positioned in the spring cavity and a tail part positioned in the second cavity, the side surface of the end part is matched with the side wall of the spring cavity, and the side surface of the tail part is matched with the side wall of the second cavity.

Furthermore, the end part, the tail part and the inner wall of the valve body form a second piston range cavity;

the side wall of the valve body is provided with a vent hole, so that the spring cavity and the second piston range cavity are respectively communicated with the outside atmosphere;

and an antifouling elbow is arranged on the vent hole.

Further, the first piston and the second piston are respectively communicated with a rodless cavity and a rod cavity of the hydraulic cylinder through a first end cover and a second end cover;

the first end cover and the second end cover are arranged at two ends of the valve body, and the first end cover and the second end cover have the same structure;

the inner pore passage of the first end cover is of a three-way structure, the three-way pore passage is respectively communicated with the rodless cavity of the hydraulic cylinder, the first piston and the outside, and the pore passage leading to the outside is provided with an oil plug.

Further, the first end cover is provided with a transverse through hole and a rodless cavity connecting port communicated with the transverse through hole;

the central axis of the transverse through hole is collinear with the central axes of the first piston, the spring and the second piston, the right end of the transverse through hole is communicated with the first piston, and the left end of the transverse through hole is provided with a first oil plug;

the rodless cavity connecting port is formed in the side face of the first end cover and is perpendicular to the transverse through hole;

the first piston, the lateral wall of the transverse through hole and the first oil plug form an oil storage cavity.

Further, the rodless cavity connection port is an orifice.

Further, the outer end faces of the first piston and the second piston are respectively provided with a first acting groove and a second acting groove, and the depths of the first acting groove and the second acting groove are 0.5-1.0 mm.

Furthermore, a first mounting groove and a second mounting groove are formed in the inner end faces of the first piston and the second piston respectively, and two ends of the spring are located in the first mounting groove and the second mounting groove. Compared with the prior art, the invention can realize at least one of the following beneficial effects:

(1) the protection device has a simple structure, can be directly installed on the control valve block of the hydraulic cylinder, saves an overflow valve and an oil overflow pipeline and simplifies a hydraulic system;

(2) the action area proportion of the first piston and the second piston is related to the action areas of the rod cavity and the rodless cavity of the hydraulic cylinder, the oil drainage proportion of oil cavities at two ends of the hydraulic cylinder is accurately controlled, the single-side deviation of the position of the piston in the hydraulic cylinder after oil drainage is not more than 1mm, and the position accuracy of the hydraulic cylinder is ensured;

(3) the protection device is communicated with the oil cavity of the hydraulic cylinder through the throttling hole, hydraulic oil flows to the protection device through the throttling hole, and therefore the situation that the instantaneous flow entering the protection device is too large is prevented, and system damping is increased.

In the invention, the technical schemes can be combined with each other to realize more preferable combination schemes. Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and drawings.

Drawings

The drawings, in which like reference numerals refer to like parts throughout, are for the purpose of illustrating the background and specific embodiments only and are not to be construed as limiting the invention.

FIG. 1 is a schematic diagram of a hydraulic cylinder and a locking mechanism in the background art;

FIG. 2 is a schematic diagram of a hydraulic cylinder with overflow protection and a locking mechanism in the background art;

FIG. 3 is a cross-sectional view of a hydraulic cylinder high pressure protection device of an exemplary embodiment;

fig. 4 is a schematic connection diagram of a hydraulic cylinder high-pressure protection device according to an embodiment.

Reference numerals:

100-hydraulic cylinder high-pressure protection device; 11-a valve body; 12-a first piston; 121-a first mounting groove; 122-first active recess; 13-a second piston; 131-an end portion; 132-tail; 133-a second mounting groove; 134-second acting recess; 14-a spring; 15-antifouling elbow; 16-Glare circle; 17-a first end cap; 171-lateral through holes; 172-rodless cavity connection port; 173-first oil block; 18-a second end cap; 181-transverse through hole; 182-a rod cavity connection port; 183-second oil plug 183;

200-hydraulic cylinder; 21-rodless cavity; 22-a rod cavity;

300-hydraulic lock;

400-relief valve;

a-a spring chamber; b-a second piston range chamber; c-oil storage cavity.

Detailed Description

The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form a part hereof, and which together with the embodiments of the invention serve to explain the principles of the invention and not to limit its scope.

The specific embodiment of the invention discloses a hydraulic cylinder high-pressure protection device 100 (which may be simply referred to as a protection device 100), as shown in fig. 3 to fig. 4, the hydraulic cylinder high-pressure protection device 100 comprises a valve body 11, and a first piston 12, a second piston 13 and a spring 14 which are installed in an inner cavity of the valve body 11, the spring 14 is located between the first piston 12 and the second piston 13, outer ends (outer sides are ends far away from the spring) of the first piston 12 and the second piston 13 are respectively communicated with a rodless cavity 21 and a rod cavity 22 of a hydraulic cylinder 200, and when the pressure in the rodless cavity 21 and the rod cavity 22 can overcome the initial elastic force of the spring 14 (when the assembled protection device 100 is not connected to an oil cavity of the hydraulic cylinder, the elastic force of the spring 14), hydraulic oil pushes the first piston 12 and the second piston 13 to compress the spring 14, and the hydraulic oil flows into the inner cavity of the valve body 11.

After the hydraulic lock 300 locks the hydraulic cylinder 200, when the ambient temperature rises, hydraulic oil is caused to expand, high pressure is formed in the rodless cavity 21 and the rod cavity 22 of the hydraulic cylinder 200, when the pressure of the hydraulic oil is greater than predetermined pressure (which means the pressure required by the hydraulic oil to push the left piston and the second piston due to the action of spring force, namely the predetermined pressure is equal to the initial spring force of the spring 14, the predetermined pressure is determined according to the type of the hydraulic cylinder, the use environment and other factors, the type and the size of the spring used in the protection device and the initial compression state are selected according to the predetermined pressure), the hydraulic oil in the rodless cavity 21 and the rod cavity 22 overcomes the spring force of the spring 14 to respectively push the first piston 12 and the second piston 13 to compress the spring 14, so that the hydraulic oil flows into the inner cavity of the valve body 11, so as to relieve the high pressure in the rodless cavity 21 and the rod cavity 22 and prevent the high pressure from damaging a hydraulic pipeline; when the ambient temperature drops back and the hydraulic oil shrinks, the pressure of the hydraulic oil is smaller than the elastic force of the spring 14, and the spring 14 pushes the first piston 12 and the second piston 13 to press the hydraulic oil back to the rodless cavity 21 and the rod cavity 22.

In order to ensure the position accuracy of the hydraulic cylinder, the hydraulic oil acts on the action areas S of the first piston 12 and the second piston 13₁₂、S₁₃(the effective areas of the first and second pistons are cross-sectional areas of the first and second pistons perpendicular to the direction of motion) to the effective areas S of the rodless chamber 21 and the rod chamber 22₂₁、S₂₂(the effective areas of the rodless chamber and the rod chamber refer to the cross-sectional areas of the rodless chamber and the rod chamber perpendicular to the moving direction of the piston of the hydraulic cylinder), and specifically, S₁₂/S₁₃＝α*S₂₁/S₂₂The research shows that the range of the adjustment coefficient alpha is 0.8-1.2, the piston position in the hydraulic cylinder after oil drainage deviates by no more than 1mm on one side, the piston in the hydraulic cylinder deviates by more than 10mm relative to the overflow valve, and the position accuracy of the hydraulic cylinder is ensured.

In order to enable the hydraulic oil to act on the first piston 12 and the second piston 13 with different acting areas, the inner cavity of the valve body 11 comprises a first cavity and a second cavity with different cross-sectional areas, the first piston 12 and the second piston 13 are respectively assembled in the first cavity and the second cavity, and the side surfaces of the first piston 12 and the second piston 13 are matched with the side walls of the first cavity and the second cavity. It should be noted that, the inner cavity of the valve body 11 further includes a spring cavity a formed between the first piston 12 and the second piston 13 for assembling the spring 14, and the cross-sectional area of the spring cavity a is not smaller than the cross-sectional areas of the first cavity and the second cavity.

In this embodiment, taking the acting area of the first piston 12 larger than that of the second piston 13 as an example, the inner cavity of the valve body 11 is a "T" shaped cavity (after being longitudinally cut along the central axis of the valve body, the shape of the inner cavity is "T" shaped), and the cross-sectional area of the first cavity is larger than that of the second cavity. In order to simplify the internal structure of the protection device and facilitate the assembly of the internal components, the cross-sectional area of the spring chamber a is equal to the cross-sectional area of the first chamber.

In order to avoid that the two ends are stressed in different directions on the central axis of the spring 14 during the compression process of the spring 14, so that the spring 14 is twisted and crushed, the central axes of the first piston 12, the second piston 13 and the spring 14 are collinear. Meanwhile, in order to prevent the first piston 12 and the second piston 13 from being displaced to distort and crush the spring 14, the side surface of the first piston 12 is matched with the side wall of the first cavity (spring cavity a), the second piston 13 comprises an end portion 131 positioned in the spring cavity a and a tail portion 132 positioned in the second cavity, two ends of the end portion 131 are respectively connected with the spring 14 and the tail portion 132, the side surface of the end portion 131 is matched with the side wall of the spring cavity a, and the side surface of the tail portion 132 is matched with the side wall of the second cavity. In addition, in order to avoid that the spring 14 is compressed to the limit position, the spring is pressed by the first piston 12 and the second piston 13, the first mounting groove 121 and the second mounting groove 133 are respectively arranged on the inner end surfaces (the end surfaces contacting with the spring 14) of the first piston 12 and the second piston 13, and two ends of the spring 14 are arranged in the first mounting groove 121 and the second mounting groove 133, so that the spring 14 can be effectively prevented from being pressed, the position of the spring 14 can be limited, and the situation that the position of the spring 14 is deviated when the protection device 100 is vibrated, and the normal use of the protection device is influenced.

In order to make the internal structure of the valve body 11 compact and form enough pressure in the limited space of the inner cavity of the valve body 11, when the preset pressure is higher, the spring 14 adopts a disc spring, and when the preset pressure is lower, the spring 14 adopts a common spiral spring.

It should be noted that when the protector is assembled and machined, the second piston pole difference chamber B is formed by the end 131, the tail portion 132 and the inner wall of the valve body 11, i.e., the length of the tail portion 132 is greater than the length of the second chamber. A vent hole is formed in the side wall of the valve body 11 (specifically, at the side wall where the spring cavity a and the second piston range cavity B are formed), so that the spring cavity a and the second piston range cavity B are respectively communicated with the outside atmosphere, and the formation of a gas spring at the spring cavity a and the second piston range cavity B is prevented, thereby affecting the normal use of the protection device. Further, in order to prevent the vent hole from being blocked by external dirt, an antifouling elbow 15 is installed on the vent hole.

In order to prevent hydraulic oil from entering the spring cavity a and contacting the spring 14, and therefore affecting the normal use of the spring 14, the greige rings 16 are arranged on the first piston 12 and the second piston 13, and the greige rings 16 play a role in sealing to prevent the hydraulic oil from flowing into the spring cavity a, specifically, the greige rings 16 on the first piston 12 are embedded on the side wall of the first piston 12, and the greige rings 16 on the second piston 13 are embedded at the right end of the side wall of the tail portion 132. In this embodiment, the first piston 12 and the second piston 13 are respectively provided with two gray rings 16, and the number of the gray rings 16 does not hinder the movement of the first piston 12 and the second piston 13 while achieving a good sealing effect.

The first piston 12 and the second piston 13 in the valve body 11 are respectively communicated with a rodless cavity 21 and a rod cavity 22 of the hydraulic cylinder 200 through a first end cover 17 and a second end cover 18, and the first end cover 17 and the second end cover 18 are respectively installed on the left end face and the right end face of the valve body 11.

A pore channel inside the first end cover 17 is of a three-way structure, one pore channel is communicated with the rodless cavity 21 of the hydraulic cylinder 200, and hydraulic oil flows into the first end cover 17 from the pore channel; a pore channel is communicated with the first piston 12, hydraulic oil flows to the first piston 12 through the pore channel, overcomes the elastic force of the spring 14 to push the first piston 12 to compress the spring 14, and the hydraulic oil flows into the valve body 11 to relieve high pressure; and the pore passage is communicated with the outside atmosphere and used for exhausting gas in the pore passage to the outside, and in order to prevent the hydraulic oil from flowing out of the pore passage, the pore passage is provided with an oil plug. The structure of the second end cap 18 is the same as that of the first end cap 17, and the inner hole channel is also a three-way structure and is respectively communicated with the rod cavity 22 and the second piston 13.

In the present embodiment, the first end cap 17 is provided with a lateral through hole 171 penetrating through left and right end faces thereof and a rodless chamber connection port 172 communicating with the lateral through hole 171, specifically, the rodless chamber connection port 172 is provided on a side face of the first end cap 17 and is perpendicular to the lateral through hole 171, and a central axis of the lateral through hole 171 is collinear with central axes of the first piston 12, the spring 14, and the second piston 13. The right end of the transverse through hole 171 is communicated with the first piston 12, and the left end is communicated with the outside atmosphere, and when the protection device 100 is assembled, a tool is used to penetrate through the transverse through hole 171 to compress the spring 14 for assisting assembly. In order to prevent the hydraulic oil from flowing out of the left end of the transverse through hole 171, a first oil plug 173 is disposed at the left end, so that the first piston 12, the side wall of the transverse through hole 171 and the first oil plug 173 form an oil storage chamber C, and when the protection device 100 is assembled, air in the oil storage chamber C is discharged through the first oil plug 173 to prevent the normal operation of the protection device 100 from being affected. The second end cap 18 has the same structure as the first end cap 17, and similarly, the second end cap 18 is also provided with a transverse through hole 181, a rod cavity connecting port 182, and a second oil plug 183, and the structural details are the same as the first end cap 17, and are not described herein again.

In this embodiment, the transverse passages 171/181 of the second end cap 18 and the first end cap 17 directly communicate with the inner cavity of the valve body 11, so that in order to prevent the first piston 12 and the second piston 13 from entering the transverse passage 171/181 under the elastic force of the spring 14, the cross-sectional area of the transverse passage 171 is smaller than that of the first piston 12, and the cross-sectional area of the transverse passage 181 is smaller than that of the second piston 13, so as to ensure that the first piston 12 and the second piston 13 always move in the inner cavity of the valve body 11. Further, in order to prevent the first piston 12 and the second piston 13 from contacting the first end cover 17 and the second end cover 18 at the initial positions, the hydraulic oil acting area is too small, the outer end surfaces (the end surfaces facing the oil storage chamber C) of the first piston 12 and the second piston 13 are respectively provided with a first acting groove 122 and a second acting groove 134, the depths of the first acting groove 122 and the second acting groove 134 are 0.5-1.0 mm, the cross-sectional area ratios of the first acting groove 122 and the second acting groove 134 are equal to the cross-sectional area ratios of the first piston 12 and the second piston 13, and the cross-sectional areas of the first acting groove 122 and the second acting groove 134 are larger than the cross-sectional area of the transverse channel 171/181, so that the hydraulic oil smoothly pushes the first piston 12 and the second piston 13.

In order to prevent the instantaneous flow of the hydraulic oil entering the protection device 100 from being too large, the rod-less cavity connection port 172 and the rod-having cavity connection port 182 are orifices, that is, the energy storage cavity C is communicated with the rod-less cavity 21 and the rod-having cavity 22 of the hydraulic cylinder 200 through the orifices, so as to increase the system damping, avoid the instantaneous flow of the hydraulic oil entering the energy storage cavity C from being too large, and prevent the hydraulic oil from pushing the piston due to the instantaneous impact force to influence the normal use of the protection device 100.

It should be noted that, in the present embodiment, the first end cap 17 and the second end cap 18 are separately provided and detachably mounted on the left and right ends of the valve body 11, so as to protect the assembly, cleaning, maintenance and replacement of the components of the device 100. However, in practical applications, the way of integrally forming the first end cap 17 and the second end cap 18 with the valve body 1 is not excluded, and at this time, in order to conveniently assemble components such as the piston and the spring, the internal structures and components of the first end cap 17 and the second end cap 18 need to be properly adjusted to realize the functions. In addition, in this embodiment, the left and right ends of the valve body 11 may be connected to the hydraulic cylinder 200 by other connecting components, and are not limited to the first end cap 17 and the second end cap 18.

The pneumatic cylinder high pressure protection device that this embodiment provided and pneumatic cylinder 200 parallel access hydraulic system, with protection device lug connection on the control valve block of pneumatic cylinder (protection device passes through the plate valve lug connection on the control valve block of pneumatic cylinder, connected mode belongs to prior art, no longer explains repeatedly). After the hydraulic lock 300 locks the hydraulic cylinder, when the environmental temperature rises to cause the sealing pressure on the two sides of the piston of the hydraulic cylinder to rise to a preset pressure, the hydraulic oil overcomes the elastic force of the spring 14 to push the first piston 12 and the second piston 13 to compress the spring, and the hydraulic oil enters the inner cavity of the valve body 11 to prevent the pressure on the two sides of the piston of the hydraulic cylinder from continuously rising to damage a hydraulic system.

The hydraulic cylinder high-pressure protection device provided by the embodiment has a simple structure, can be directly installed on a hydraulic cylinder control valve block, saves an oil spill valve and an oil spill pipeline, and simplifies a hydraulic system; meanwhile, the action areas of the first piston and the second piston are related to the action areas of the rodless cavity and the rod cavity of the hydraulic cylinder, so that the proportion of the oil quantity of the oil cavities at the two ends of the hydraulic cylinder is accurately controlled, and the position precision of the hydraulic cylinder after oil overflow is ensured.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention.

Claims

1. The high-pressure protection device of the hydraulic cylinder is characterized by comprising a valve body (11), a first piston (12), a second piston (13) and a spring (14), wherein the first piston (12), the second piston (13) and the spring (14) are installed in an inner cavity of the valve body (11);

the spring (14) is positioned between the first piston (12) and the second piston (13);

the outer ends of the first piston (12) and the second piston (13) are respectively communicated with a rodless cavity (21) and a rod cavity (22) of the hydraulic cylinder (200);

when the pressure in the rodless cavity (21) and the rod cavity (22) overcomes the initial elastic force of the spring (14), hydraulic oil pushes the first piston (12) and the second piston (13) to compress the spring (14), and the hydraulic oil flows to the inner cavity of the valve body (11);

the inner cavity of the valve body (11) comprises a first cavity and a second cavity, and the first piston (12) and the second piston (13) are respectively arranged in the first cavity and the second cavity;

a spring cavity (A) for assembling the spring (14) is formed between the first piston (12) and the second piston (13);

the cross-sectional area of the spring cavity (A) is equal to the cross-sectional area of the first cavity and larger than the cross-sectional area of the second cavity;

the central axes of the first piston (12), the second piston (13) and the spring (14) are collinear;

the side surface of the first piston (12) is matched with the side wall of the spring cavity (A);

the second piston (13) comprises an end part (131) positioned in the spring cavity (A) and a tail part (132) positioned in the second cavity, the side surface of the end part (131) is matched with the side wall of the spring cavity (A), and the side surface of the tail part (132) is matched with the side wall of the second cavity.

2. The hydraulic cylinder high pressure protection device of claim 1Characterized in that the active areas S of the first and second pistons (12, 13)₁₂、S₁₃The ratio of the effective area S of the rodless cavity (21) and the rodless cavity (22)₂₁、S₂₂The proportion relation is as follows: s₁₂/S₁₃＝α*S₂₁/S₂₂，

Wherein the range of the adjustment coefficient alpha is 0.8-1.2.

3. Hydraulic cylinder high pressure protection arrangement according to claim 2, characterized in that the end (131), the tail (132) and the inner wall of the valve body (11) constitute a second piston pole difference chamber (B);

the side wall of the valve body (11) is provided with a vent hole, so that the spring cavity (A) and the second piston range cavity (B) are respectively communicated with the outside atmosphere;

and an antifouling elbow (15) is arranged on the vent hole.

4. The hydraulic cylinder high pressure protection device according to any one of claims 1-3, characterized in that the first piston (12) and the second piston (13) are respectively communicated with the rodless cavity (21) and the rod cavity (22) of the hydraulic cylinder (200) through a first end cover (17) and a second end cover (18);

the first end cover (17) and the second end cover (18) are arranged at two ends of the valve body (11), and the first end cover (17) and the second end cover (18) have the same structure;

the inner pore channel of the first end cover (17) is of a three-way structure, the three-way pore channel is respectively communicated with the rodless cavity (21) of the hydraulic cylinder (200), the first piston (12) and the outside, and an oil plug is arranged on the pore channel leading to the outside.

5. The hydraulic cylinder high-pressure protection device according to claim 4, characterized in that the first end cover (17) is provided with a transverse through hole (171) and a rodless cavity connecting port (172) communicated with the transverse through hole (171);

the central axis of the transverse through hole (171) is collinear with the central axes of the first piston (12), the spring (14) and the second piston (13), the right end of the transverse through hole (171) is communicated with the first piston (12), and the left end is provided with a first oil plug (173);

the rodless cavity connecting port (172) is formed in the side face of the first end cover (17) and is perpendicular to the transverse through hole (171);

the first piston (12), the side wall of the transverse through hole (171) and the first oil plug (173) form an oil storage chamber (C).

6. Hydraulic cylinder high pressure protection arrangement according to claim 5, characterized in that the rodless chamber connection port (172) is an orifice.

7. The hydraulic cylinder high-pressure protection device according to claim 5, characterized in that the outer end surfaces of the first piston (12) and the second piston (13) are respectively provided with a first acting groove (122) and a second acting groove (134), and the depths of the first acting groove (122) and the second acting groove (134) are 0.5-1.0 mm.

8. The hydraulic cylinder high-pressure protection device according to any one of claims 1-3 and 5-7, wherein the inner end surfaces of the first piston (12) and the second piston (13) are respectively provided with a first mounting groove (121) and a second mounting groove (133), and two ends of the spring (14) are positioned in the first mounting groove (121) and the second mounting groove (133).

9. The hydraulic cylinder high-pressure protection device according to claim 4, wherein the inner end surfaces of the first piston (12) and the second piston (13) are respectively provided with a first mounting groove (121) and a second mounting groove (133), and two ends of the spring (14) are located in the first mounting groove (121) and the second mounting groove (133).