CN217496129U

CN217496129U - Hydraulic connecting rod

Info

Publication number: CN217496129U
Application number: CN202221023550.1U
Authority: CN
Inventors: 刘欢; 陈刚; 林胜; 邹敏佳; 汤腾; 彭伟伦; 李伟; 刘文松
Original assignee: Zhuzhou Times New Material Technology Co Ltd
Current assignee: Zhuzhou Times New Material Technology Co Ltd
Priority date: 2022-04-29
Filing date: 2022-04-29
Publication date: 2022-09-27
Anticipated expiration: 2032-04-29

Abstract

The utility model relates to a hydraulic pressure connecting rod, include: the body of rod, piston and ball pivot. The piston is movably arranged in the rod body, and the rod body is divided into a first liquid cavity and a second liquid cavity by the piston. When the piston moves in the rod body, the liquid medium only flows between the first liquid cavity and the second liquid cavity, and a hydraulic station or an oil source and other liquid storage containers are not needed. The structure is simple, the length of the connecting rod is adjustable, and the connecting rod has the characteristics of keeping unchanged, freely stretching, extending in a one-way follow-up mode or shortening in a one-way follow-up mode. The torsion bar system is applied to the anti-rolling torsion bar system, and can realize the one-way anti-rolling effect.

Description

Hydraulic connecting rod

Technical Field

The utility model relates to a rail vehicle technical field, concretely relates to hydraulic pressure connecting rod.

Background

With the continuous improvement of the requirements of the running speed and riding comfort of the rail vehicle, the conventional rail vehicle suspension system is difficult to meet the requirements of safety and comfort when a train passes through a high-speed curve. The pendulum-type train can let the automobile body initiative tilt before the vehicle arrives the curve, relies on self gravity balance centrifugal force, consequently compares traditional rail vehicle security and travelling comfort problem when can solving high-speed curve better and pass through.

The anti-rolling torsion bar is used for preventing rolling of the rail vehicle caused by curve passing, strong wind and bumping and ensuring driving safety. When the vehicle body is actively tilted, the anti-roll torsion bar hinders the active tilting of the vehicle body, and therefore, it is necessary to improve the anti-roll torsion bar.

When the rail vehicle runs on a straight line or a large curvature radius line, the anti-rolling torsion bar is required to provide bidirectional anti-rolling moment to prevent the vehicle body from rolling laterally; when the rail vehicle runs on a small-curvature radius line, the anti-rolling torsion bar is required to be matched with the air spring system, so that the vehicle body tilts towards the inner side of a curve; but also can provide one-way anti-rolling moment to prevent the car body from rolling towards the outer side of the curve.

This requires that the link length of the anti-roll torsion bar can be adjusted in real time: when the rail vehicle runs on a straight line or a large curvature radius line, the length of the connecting rod is required to be kept unchanged; when the rail vehicle runs on a small-curvature radius line, the length of the connecting rod is required to be capable of performing unidirectional follow-up extension or unidirectional follow-up shortening along with the tilting of the vehicle body so as to provide unidirectional anti-rolling moment.

The connecting rod of the traditional anti-rolling torsion bar has fixed length in the running process of the vehicle and cannot be adjusted in real time according to the running state. Therefore, the technical problems to be solved by the application are as follows: the length of the connecting rod can be adjusted in real time according to the running requirement of the vehicle: the device is switched among several states of fixed length, free expansion and contraction, and one-way follow-up extension or one-way follow-up shortening.

Through patent retrieval, the following patents have a certain relationship with the present application:

1. the invention relates to a self-positioning adjusting device of an anti-rolling torsion bar, which is a Chinese invention patent with the application number of 201910683078.0, the application date of 2019.07.26, the publication number of CN110329298A and the publication date of 2019.10.15, the name of which is ' self-positioning adjusting method and device of the anti-rolling torsion bar ' and the application person of ' New Material science and technology Limited company in shoal ' in China ', wherein the invention patent divides the anti-rolling torsion bar connecting rod into two parts from the middle and connects the two parts of the connecting rod through a self-positioning adjusting device to form the anti-rolling torsion bar connecting rod with the self-positioning adjusting device; the self-positioning adjusting device with the connecting rod length adjusting device and the self-positioning adjusting device is arranged between the two parts of the connecting rod, and the two parts of the connecting rod are connected through the self-positioning adjusting device with the connecting rod length adjusting device and the self-positioning adjusting device, so that the influence on the service life of the node of the connecting rod due to the relative position deviation of the upper connecting rod node and the lower connecting rod node of the adjustable vertical connecting rod in the loading process is avoided; meanwhile, the maintenance process of the product is optimized, and the product maintenance can be completed by replacing the locking nut without adopting an additional tool. However, the connecting rod of the patent can only adjust the length during installation or maintenance, cannot realize real-time unidirectional follow-up adjustment of the length of the connecting rod, and cannot provide unidirectional anti-rolling moment.

2. The invention relates to a Chinese invention patent with the application number of 202011125612.5, the application date of 2020.10.20, the publication number of CN112158224A and the publication number of 2021.01.01, named as a real-time active adjusting method and an active anti-rolling torsion bar system for the length of a connecting rod, and the application is ' New Material science and technology Co., Ltd ' in Zhou time ', and the invention patent relates to a real-time active adjusting method for the length of the connecting rod: the active adjusting device is additionally arranged on the connecting rod, so that the length of the connecting rod can be actively adjusted in real time according to a control instruction. Thereby the defect that traditional connecting rod length is fixed, unable adjustment has been solved. The invention also relates to an active anti-roll torsion bar system: the method comprises the following steps: the connecting rod is provided with the ball screw mechanism, the length of the connecting rod can be rapidly adjusted in real time according to a control instruction, so that the torsion bar is subjected to torsional deformation, and further, the side rolling resisting moment is actively provided for the train body, the side rolling angle of the train body is actively adjusted, the speed and the safety of the train passing through a curve are improved, and the running speed of the train is improved. However, the connecting rod of the patent can only actively adjust the length of the connecting rod, the length of the connecting rod can not realize unidirectional follow-up extension or unidirectional follow-up shortening, and unidirectional anti-rolling moment can not be provided.

3. The invention relates to a passive adjusting method for connecting rod length, which is a Chinese invention patent with the application number of 202110004969.6, the application date of 2021.01.04, the publication number of CN112644538A and the publication number of 2021.04.13, the name of which is a passive adjusting method and a passive control torsion bar system for connecting rod length, and the application person of the Chinese invention patent is' New Material science and technology Co., Ltd in Zhou time, and the invention patent relates to a passive adjusting method for connecting rod length: by additionally arranging the passive adjusting device on the connecting rod, the switching between two states of loosening or locking can be realized in real time according to a control instruction, so that the length of the connecting rod can be adjusted or kept fixed. The invention also relates to a passive control torsion bar system: the method comprises the following steps: the connecting rod is provided with a passive adjusting device which can be switched between two states of loosening or locking in real time according to a control instruction, so that the length of the connecting rod can be adjusted or kept fixed. When the torsion bar system runs on a straight line or a large curvature radius line of a vehicle, the length of the connecting rod is kept fixed, so that the torsion bar system plays a role in resisting side rolling of a traditional torsion bar; when the vehicle passes through a curve, the length of the connecting rod can be freely stretched along with the active tilting system so as to adjust the side roll angle of the vehicle body by matching with the tilting system. However, the connecting rod of the patent can only be switched between locking and free expansion, the length of the connecting rod cannot realize unidirectional follow-up extension or unidirectional follow-up shortening, and unidirectional anti-rolling moment cannot be provided.

4. The utility model discloses an adjustable anti-rolling torsion bar connecting rod, which comprises a connecting rod shaft, a connecting rod joint, a joint bearing, a check ring and the like, wherein the application number is 201621408157.9, the application date is 2016.12.21, the publication number is CN206265060U, the publication date is 2017.06.20, the name is 'an adjustable anti-rolling torsion bar connecting rod', and the application person is 'Nanjing Redwei new technology Limited company'; two ends of the connecting rod shaft are connected with the joint bearing; the side surfaces of two ends of the connecting rod shaft comprise a connecting rod inner hole and an inner hole groove, a check ring is arranged in the inner hole groove, and the joint bearing is inserted into the connecting rod inner hole. The connecting rod shaft is also provided with a connecting rod joint which is arranged at one end of the connecting rod. However, the connecting rod of the patent can only adjust the length during installation or maintenance, cannot realize real-time unidirectional follow-up adjustment of the length of the connecting rod, and cannot provide unidirectional anti-rolling moment.

5. The utility model discloses a utility model patent of application number "201621166973.3", application date "2016.11.02", publication number "CN 206141565U", publication number "2017.05.03", name "be used for the vertical connecting rod adjustable anti-rolling torsion bar device of linear electric motor vehicle", applicant for "shozhou era new material science and technology limited company", this utility model patent discloses a be used for the vertical connecting rod adjustable anti-rolling torsion bar device of linear electric motor vehicle, including torsion bar axle, torsion arm, supporting seat constitution, vertical connecting rod constitution includes left-handed bulb, vertical connecting rod and dextrorotation bulb, the upper end and the lower extreme of vertical connecting rod all set up to take the internal thread opposite direction at internal thread's tubulose and vertical connecting rod both ends; the left-handed ball head and the right-handed ball head are respectively connected to the upper end and the lower end of the vertical connecting rod in a threaded connection mode. However, the connecting rod of the patent can only adjust the length during installation or maintenance, cannot realize real-time unidirectional follow-up adjustment of the length of the connecting rod, and cannot provide unidirectional anti-rolling moment.

However, the above patent is not the same as the technical solution of the present application.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is to the defect that exists among the prior art, a hydraulic link that connecting rod length can real-time one-way follow-up adjust is provided.

In order to solve the technical problem, the utility model discloses the technical scheme who takes does: a hydraulic link, comprising: the piston is movably arranged in the rod body and divides the rod body into a first liquid cavity and a second liquid cavity, and liquid media are filled in the first liquid cavity and the second liquid cavity. The first liquid cavity is communicated with the second liquid cavity through the flow channel, when the piston moves in the rod body, the liquid medium only flows between the first liquid cavity and the second liquid cavity, and the volume of the first liquid cavity is reduced or increased and is equal to the volume of the second liquid cavity. The hydraulic connecting rod does not need a hydraulic station or an oil source, does not need other liquid storage containers, and has simple structure, adjustable length and various characteristics.

Furthermore, a first rod piece is arranged in the first liquid cavity, one end of the first rod piece is connected with one side of the piston, and the other end of the first rod piece penetrates through the first liquid cavity in a sealing mode; a second rod piece is arranged in the second liquid cavity, one end of the second rod piece is connected with the other side of the piston, and the other end of the second rod piece penetrates through the second liquid cavity in a sealing mode; the first rod piece and the second rod piece move in the rod body along with the piston; the first rod piece or the second rod piece has the same cross-sectional dimension in the moving direction. So that the decreased volume or the increased volume of the first liquid cavity is always equal to the increased volume or the decreased volume of the second liquid cavity.

Furthermore, the first rod piece and the second rod piece are cylindrical, and the diameter of the first rod piece is the same as that of the second rod piece. The cylindrical rod piece is convenient to process, low in production cost, free of directionality and simple and convenient to install.

Furthermore, a balance cavity is arranged in the rod body along the moving direction of the piston, and the other end of the rod piece II is movably arranged in the balance cavity; the balancing cavity is communicated with the atmosphere through a vent hole. The air pressure formed by the balance cavity is avoided, and the movement of the rod piece II is prevented from being influenced.

Furthermore, the rod piece I is in threaded connection with the piston, and the rod piece II and the piston are integrally formed, so that the processing and the installation are facilitated.

Furthermore, the other end of the rod I is provided with a first spherical hinge, and one end of the rod body is provided with a second spherical hinge. The two ends of the hydraulic connecting rod are hinged, so that the hydraulic connecting rod is prevented from bearing bending moment and torque, the stress condition of the hydraulic connecting rod is improved, the stress of the hydraulic connecting rod is reduced, and the service life is prolonged.

Furthermore, the flow channel is arranged on the rod body, the flow channel is provided with a control part, and the flow of the liquid medium is controlled through the control part. Thereby changing the characteristics of the hydraulic link such that link length: keeping unchanged, freely stretching, extending in a unidirectional and unidirectional following way or shortening in a unidirectional and unidirectional following way.

Further, the control component comprises a through valve, and the first liquid cavity is communicated with or disconnected from the second liquid cavity through the through valve.

Further, the flow passage includes: a first flow passage and a second flow passage, the control member comprising: a straight-through valve and a one-way valve; a first straight-through valve and a first one-way valve are arranged on the first flow passage, and the liquid medium in the first liquid cavity can only flow to a second liquid cavity through the first one-way valve and the first straight-through valve; and a second straight-through valve and a second one-way valve are arranged on the second flow channel, and the liquid medium in the second liquid cavity can only flow to the first liquid cavity through the second one-way valve and the second straight-through valve.

Furthermore, the first straight-through valve and the second straight-through valve adopt normally closed electromagnetic valves; the first straight-through valve and the first check valve are integrated and mounted on the periphery of the rod body, the second straight-through valve and the second check valve are integrated and mounted on the periphery of the rod body, and the mounting included angle between the first straight-through valve and the second straight-through valve is 60 degrees +/-30 degrees. The interference between the hydraulic connecting rod and parts of the installation part is avoided, so that the hydraulic connecting rod can be installed at the position with limited position.

The utility model has the advantages that: the hydraulic connecting rod utilizes the piston to divide the rod body into the first liquid cavity and the second liquid cavity, when the piston moves in the rod body, liquid media only flow between the first liquid cavity and the second liquid cavity, and a hydraulic station or an oil source and other liquid storage containers are not needed. The structure is simple, the length of the connecting rod is adjustable, and the connecting rod has the characteristics of keeping unchanged, freely stretching, extending in a one-way follow-up mode or shortening in a one-way follow-up mode. The torsion bar system is applied to the anti-rolling torsion bar system, and can realize the one-way anti-rolling effect.

Drawings

Figure 1 is a schematic view of the principle of a hydraulic link,

figure 2 is a schematic perspective view of a hydraulic link,

figure 3 is a schematic front view of a hydraulic link,

figure 4 is a schematic top view of a hydraulic link,

figure 5 is a schematic cross-sectional view a-a of the hydraulic link of figure 4,

figure 6 is a schematic view of the hydraulic link when freely extended and retracted,

figure 7 is a schematic diagram of a hydraulic connecting rod during unidirectional follow-up extension,

FIG. 8 is a schematic view of a hydraulic link during one-way servo-shortening.

In the figure: 1-first ball hinge, 2-first rod piece, 3-rod piece, 31-first liquid cavity, 32-second liquid cavity, 33-balance cavity, 4-piston, 5-second rod piece, 6-second ball hinge, 7-first flow channel, 71-first straight-through valve, 72-first one-way valve, 8-second flow channel, 81-second straight-through valve, 82-second one-way valve, phi-first straight-through valve and second straight-through valve are installed with an included angle, U-liquid flow direction and V-connecting rod follow-up direction.

Detailed Description

The invention will be further described by means of specific embodiments and with reference to the accompanying drawings:

the hydraulic link is as shown in fig. 1 to 5: a hydraulic link, comprising: the ball hinge comprises a first ball hinge 1, a first rod piece 2, a rod body 3, a piston 4, a second rod piece 5, a second ball hinge 6, a first flow passage 7 and a second flow passage 8, wherein the first flow passage 7 is provided with a first straight-through valve 71 and a first check valve 72, and the second flow passage 8 is provided with a second straight-through valve 81 and a second check valve 82.

The piston 4 is movably arranged in the rod body 3, and divides the rod body 3 into a first liquid cavity 31 and a second liquid cavity 32, and the first liquid cavity 31 and the second liquid cavity 32 are filled with liquid media. A rod piece I2 is arranged in the liquid cavity I31, the rod piece I2 is in threaded connection with the piston 4, and the other end of the rod piece I2 penetrates through the liquid cavity I31 in a sealing mode; a second rod piece 5 is arranged in the second liquid cavity 32, the second rod piece 5 and the piston 4 are integrally formed, and the other end of the second rod piece 5 penetrates through the second liquid cavity 32 in a sealing mode; the first rod 2 and the second rod 5 are cylindrical, the first rod 2 and the second rod 5 move along with the piston 4 in the rod 3, and the diameter of the first rod 2 is the same as that of the second rod 5. A balance cavity 33 is arranged in the rod body 3 along the moving direction of the piston 4, and the other end of the rod piece II 5 is movably arranged in the balance cavity 33; the balancing chamber 33 is vented to atmosphere through a vent.

The first liquid cavity 31 is communicated with the second liquid cavity 32 through the first flow passage 7 and the second flow passage 8, and when the piston 4 moves in the rod body 3, the liquid medium only flows between the first liquid cavity 31 and the second liquid cavity 32. The decreased or increased volume of the first chamber 31 is equal to the increased or decreased volume of the second chamber 32.

The first flow passage 7 is provided with a first straight-through valve 71 and a first check valve 72, and the liquid medium in the first liquid cavity 31 can only flow to the second liquid cavity 32 through the first check valve 72 and the first straight-through valve 71. The first straight-through valve 71 adopts a normally closed type electromagnetic valve. The first straight-through valve 71 and the first check valve 72 are integrated and are arranged on the periphery of the rod body 3. The second flow passage 8 is provided with a second through valve 81 and a second one-way valve 82, and the second through valve 81 and the second one-way valve 82 are integrated and are arranged on the periphery of the rod body 3. The liquid medium in the second liquid cavity 32 can only flow to the first liquid cavity 31 through the second check valve 82 and the second through valve 81, and the second through valve 81 adopts a normally closed electromagnetic valve.

The included angle phi between the first straight-through valve 71 and the second straight-through valve 81 is 60 degrees +/-30 degrees. The interference between the parts of the installation parts and the interference between the first straight-through valve 71 and the second straight-through valve 81 are avoided, so that the hydraulic connecting rod can be installed at the position limited.

The link length remains unchanged as shown in fig. 1: at this time, the first straight-through valve 71 and the second straight-through valve 81 are both disconnected, and the liquid medium cannot flow between the first liquid chamber 31 and the second liquid chamber 32. If the hydraulic connecting rod is subjected to a pulling force, the rod piece I2 has a tendency to drive the piston 4 to move upwards. Because the liquid medium is almost incompressible, the pressure in the first liquid cavity 31 is sharply increased, the pressure in the second liquid cavity 32 is reduced to form negative pressure, downward differential pressure is formed on two sides of the piston 4, the differential pressure acts on the piston 4 to form downward balancing force, the downward balancing force is balanced with the pulling force borne by the hydraulic connecting rod, the piston 4 cannot move, and the length of the connecting rod is kept unchanged.

On the contrary, if the hydraulic link is subjected to pressure, the first rod 2 tends to move the piston 4 downward. At this time, the pressure in the first liquid cavity 31 is reduced to form negative pressure, the pressure in the second liquid cavity 32 is increased sharply, upward pressure difference is formed on two sides of the piston 4, the pressure difference acts on the piston 4 to form upward balance force, the balance force is balanced with the pressure born by the hydraulic connecting rod, the piston 4 does not move, and the length of the connecting rod is kept unchanged.

The length of the connecting rod is freely extended and contracted as shown in figure 6: at this time, the first straight-through valve 71 and the second straight-through valve 81 are communicated. If the hydraulic connecting rod is subjected to a pulling force, the rod piece I2 has a tendency to drive the piston 4 to move upwards. At this time, the pressure in the first liquid chamber 31 is increased, and the pressure in the second liquid chamber 32 is decreased to form negative pressure. The liquid medium in the first liquid cavity 31 flows to the second liquid cavity 32 through the first check valve 72 and the first straight-through valve 71, the liquid medium flowing out of the first liquid cavity 31 is equal to the liquid medium flowing into the second liquid cavity 32, only a small pressure difference is formed between two sides of the piston 4, the piston 4 is enabled to move upwards, and the length of the connecting rod is enabled to extend freely.

On the contrary, if the hydraulic link is subjected to pressure, the first rod 2 tends to move the piston 4 downward. At this time, the pressure in the first liquid chamber 31 is reduced to form negative pressure, and the pressure in the second liquid chamber 32 is increased. The liquid medium in the second liquid cavity 32 flows to the first liquid cavity 31 through the second one-way valve 82 and the second straight-through valve 81, the liquid medium flowing out of the second liquid cavity 32 is equal to the liquid medium flowing into the first liquid cavity 31, and only a small pressure difference is formed between two sides of the piston 4, so that the piston 4 moves downwards, and the length of the connecting rod is freely shortened.

When the connecting rod extends in a one-way following mode, as shown in figure 7: the one-way follow-up extension of the connecting rod is as follows: the length of the connecting rod is freely extended under the action of tensile force, and when the tensile force is converted into pressure, the length of the connecting rod is kept unchanged. At this time, the first straight-through valve 71 is communicated, and the second straight-through valve 81 is disconnected. If the hydraulic connecting rod is subjected to a pulling force, the rod piece I2 has a tendency to drive the piston 4 to move upwards. At this time, the pressure in the first liquid chamber 31 is increased, and the pressure in the second liquid chamber 32 is decreased to form negative pressure. The liquid medium in the first liquid cavity 31 flows to the second liquid cavity 32 through the first check valve 72 and the first straight-through valve 71, the liquid medium flowing out of the first liquid cavity 31 is equal to the liquid medium flowing into the second liquid cavity 32, and only a small pressure difference can be formed between two sides of the piston 4, so that the piston 4 moves upwards. Under the action of the tensile force, the length of the connecting rod can be freely extended. If the pulling force applied to the hydraulic link is converted into a pressure, the second straight-through valve 81 is disconnected, and the liquid medium in the second liquid chamber 32 cannot flow to the first liquid chamber 31. At this time, the pressure in the first liquid chamber 31 is reduced to form negative pressure, the pressure in the second liquid chamber 32 is increased sharply, an upward pressure difference is formed on two sides of the piston 4, the pressure difference acts on the piston 4 to form an upward balancing force, the upward balancing force is balanced with the pressure born by the hydraulic connecting rod, and the piston 4 cannot move. But under pressure the link length remains constant.

When the connecting rod is shortened in a one-way follow-up mode, as shown in figure 8: the one-way follow-up shortening of the connecting rod is as follows: the length of the connecting rod is freely shortened under the action of pressure, and when the pressure is converted into pulling force, the length of the connecting rod is kept unchanged. At the moment, the first straight-through valve 71 is disconnected, and the second straight-through valve 81 is communicated. If the hydraulic connecting rod is subjected to pressure, the first rod piece 2 has a tendency to drive the piston 4 to move downwards. At this time, the pressure in the first liquid chamber 31 is reduced to form negative pressure, and the pressure in the second liquid chamber 32 is increased. The liquid medium in the second liquid cavity 32 flows to the first liquid cavity 31 through the second check valve 82 and the second straight-through valve 81, the liquid medium flowing out of the second liquid cavity 32 is equal to the liquid medium flowing into the first liquid cavity 31, and only a small pressure difference is formed between two sides of the piston 4, so that the piston 4 moves downwards. Under the action of the pulling force, the length of the connecting rod can be freely shortened. If the pressure borne by the hydraulic link is converted into a tensile force, the liquid medium in the first liquid chamber 31 cannot flow to the second liquid chamber 32 because the first straight-through valve 71 is disconnected. At this time, the pressure in the first liquid chamber 31 is increased sharply, the pressure in the second liquid chamber 32 is reduced to form negative pressure, a downward differential pressure is formed on two sides of the piston 4, the differential pressure acts on the piston 4 to form a downward balancing force, the downward balancing force is balanced with the pulling force borne by the hydraulic connecting rod, and the piston 4 cannot move. But under the action of the pulling force, the length of the connecting rod is kept unchanged.

In summary, the following steps: the utility model has the advantages that: the hydraulic connecting rod utilizes the piston to divide the rod body into the first liquid cavity and the second liquid cavity, when the piston moves in the rod body, liquid media only flow between the first liquid cavity and the second liquid cavity, and a hydraulic station or an oil source and other liquid storage containers are not needed. The structure is simple, the length of the connecting rod is adjustable, and the connecting rod has the characteristics of keeping unchanged, freely stretching, extending in a one-way follow-up mode or shortening in a one-way follow-up mode. The torsion bar system is applied to the anti-rolling torsion bar system, and can realize the one-way anti-rolling effect.

The above embodiments are provided only for the purpose of illustration, not for the limitation of the present invention, and those skilled in the relevant art can make various changes or modifications without departing from the spirit and scope of the present invention, so all equivalent technical solutions should also belong to the protection scope of the present invention, and the protection scope of the present invention should be defined by the claims.

Claims

1. A hydraulic link, comprising: the body of rod (3) and piston (4), piston (4) activity sets up in the body of rod (3), separates into sap cavity one (31) and sap cavity two (32) with the body of rod (3), is full of liquid medium in sap cavity one (31) and sap cavity two (32), its characterized in that: the first liquid cavity (31) is communicated with the second liquid cavity (32) through a flow passage, when the piston (4) moves in the rod body (3), the liquid medium only flows between the first liquid cavity (31) and the second liquid cavity (32), and the volume decreased or increased by the first liquid cavity (31) is equal to the volume increased or decreased by the second liquid cavity (32).

2. The hydraulic link of claim 1, wherein: a first rod piece (2) is arranged in the first liquid cavity (31), one end of the first rod piece (2) is connected with one side of the piston (4), and the other end of the first rod piece (2) penetrates through the first liquid cavity (31) in a sealing mode; a second rod piece (5) is arranged in the second liquid cavity (32), one end of the second rod piece (5) is connected with the other side of the piston (4), and the other end of the second rod piece (5) penetrates through the second liquid cavity (32) in a sealing mode; the rod piece I (2) and the rod piece II (5) move in the rod body (3) along with the piston (4); the first rod piece (2) or the second rod piece (5) has the same cross-sectional dimension in the moving direction.

3. The hydraulic link of claim 2, wherein: the first rod piece (2) and the second rod piece (5) are cylindrical, and the diameter of the first rod piece (2) is the same as that of the second rod piece (5).

4. The hydraulic link of claim 3, wherein: a balance cavity (33) is arranged in the rod body (3) along the moving direction of the piston (4), and the other end of the rod piece II (5) is movably arranged in the balance cavity (33); the balancing chamber (33) is connected to the atmosphere via a vent hole.

5. The hydraulic link of claim 4, wherein: the first rod piece (2) is in threaded connection with the piston (4), and the second rod piece (5) and the piston (4) are integrally formed.

6. The hydraulic link of any one of claims 1 to 5, wherein: the other end of the rod piece I (2) is provided with a spherical hinge I (1), and one end of the rod body (3) is provided with a spherical hinge II (6).

7. The hydraulic link of claim 6, wherein: the flow channel is arranged on the rod body (3), and a control part is arranged on the flow channel and used for controlling the flow of the liquid medium.

8. The hydraulic link of claim 7, wherein: the control component comprises a straight-through valve, and the first liquid cavity (31) is communicated or disconnected with the second liquid cavity (32) through the straight-through valve.

9. The hydraulic link of claim 8, wherein: the flow path includes: a first flow path (7) and a second flow path (8), the control member comprising: a straight-through valve and a one-way valve; a first straight-through valve (71) and a first check valve (72) are arranged on the first flow passage (7), and the liquid medium in the first liquid cavity (31) can only flow to a second liquid cavity (32) through the first check valve (72) and the first straight-through valve (71); and a second straight-through valve (81) and a second one-way valve (82) are arranged on the second flow channel (8), and the liquid medium in the second liquid cavity (32) can only flow to the first liquid cavity (31) through the second one-way valve (82) and the second straight-through valve (81).

10. The hydraulic link of claim 9, wherein: the first straight-through valve (71) and the second straight-through valve (81) adopt normally closed electromagnetic valves; the first straight-through valve (71) and the first check valve (72) are integrated and installed on the periphery of the rod body (3), the second straight-through valve (81) and the second check valve (82) are integrated and installed on the periphery of the rod body (3), and the installation included angle phi between the first straight-through valve (71) and the second straight-through valve (81) is 60 degrees +/-30 degrees.