CN115126742B

CN115126742B - Zero-leakage hydraulic cylinder

Info

Publication number: CN115126742B
Application number: CN202210626225.2A
Authority: CN
Inventors: 蔡伟; 刘金恒; 张宇杭; 郭顺顺; 赵静一
Original assignee: Yanshan University
Current assignee: Yanshan University
Priority date: 2022-06-02
Filing date: 2022-06-02
Publication date: 2023-03-31
Anticipated expiration: 2042-06-02
Also published as: JP2023178211A; JP7470274B2; CN115126742A

Abstract

The invention relates to a zero-leakage hydraulic cylinder, which comprises a cylinder barrel, a piston, a rodless cavity oil bag and a rod cavity oil bag, wherein the piston is arranged in the cylinder barrel; the piston, the rodless cavity oil bag and the rod cavity oil bag are all arranged inside the cylinder barrel, and the piston is connected with the inner wall of the cylinder barrel in a sliding manner; a first oil through hole and a second oil through hole are formed in the side wall of the cylinder barrel; the side wall of the first surface of the rodless cavity oil bag is provided with a first opening, the first opening is connected with the first oil through hole, the side wall of the first surface of the rodless cavity oil bag is provided with a second opening, and the second opening is connected with the second oil through hole. The double-bag structure solves the problems of internal leakage and external leakage of oil in the hydraulic cylinder, avoids a series of leakage problems caused by the fact that the viscosity of the oil is reduced due to system temperature rise, reduces the processing precision and cost of the inner wall of the hydraulic cylinder and the piston, improves the control precision, enables the hydraulic cylinder to be easy to realize high pressure, breaks through the traditional cylindrical limitation of the appearance of the hydraulic cylinder, realizes the abnormity, and meets the space requirements of different occasions for the placement and the use of the hydraulic cylinder.

Description

Zero-leakage hydraulic cylinder

Technical Field

The invention relates to the technical field of hydraulic pressure, in particular to a zero-leakage hydraulic cylinder.

Background

The hydraulic cylinder is an actuating element which converts hydraulic energy into mechanical energy to realize reciprocating linear motion or reciprocating swing, and has the advantages of simple structure, reliable work, large transmission power, easy manufacture and the like, so the hydraulic cylinder is widely applied to various hydraulic systems.

However, the hydraulic cylinder used in the field of mechanical engineering at the present stage has a common problem that oil leaks in and out in the use process of the hydraulic cylinder, wherein the internal leakage refers to the leakage of the hydraulic oil from a high-pressure cavity to a low-pressure cavity of the hydraulic cylinder, and the external leakage refers to the leakage of the hydraulic oil from the hydraulic cylinder to the outside; once the oil leaks in or out, the following problems occur:

on one hand, both internal leakage and external leakage can cause great influence on hydraulic transmission performance, for example, problems of inaccurate transmission ratio caused by oil leakage, vibration and noise caused by insufficient oil supply and absorption of hydraulic elements, environmental pollution caused by leakage oil and the like are solved, especially when a system works, the temperature rises to cause the viscosity of the oil to fall, the leakage phenomenon is more serious, and the influence on the hydraulic transmission is more adverse;

on the other hand, the appearance of the hydraulic cylinder and the highest pressure of the system are limited by controlling the oil leakage, the existing hydraulic cylinder is designed into a cylindrical shape, namely, the sealing performance of relative sliding when two cylindrical surfaces are contacted is better, but when the system needs higher working pressure, the leakage is more serious, the leakage can be reduced only by improving the manufacturing precision of the hydraulic cylinder and the sealing performance of a sealing element, and the processing and manufacturing cost of the hydraulic cylinder is increased substantially invisibly.

Disclosure of Invention

In order to solve the technical problems mentioned in the background art, the invention provides a zero-leakage hydraulic cylinder, a rodless cavity oil bag and a rod cavity oil bag are arranged in a cylinder body, so that the leakage-free condition of the cylinder body is realized, the working environment is not polluted any more, the transmission performance caused by the viscosity reduction of oil due to the temperature rise is also solved, the transmission ratio of a hydraulic system is more accurate, and the control precision of the hydraulic cylinder is also improved; more significant, the invention reduces the high processing precision requirement on the inner wall of the hydraulic cylinder and the side surface of the piston, thereby reducing the overall processing and manufacturing cost of the hydraulic cylinder and better realizing the high pressure and ultrahigh pressure of the hydraulic cylinder; finally, the appearance of the traditional cylindrical hydraulic cylinder and the arrangement of the double oil bags are changed, so that the hydraulic cylinder can be changed from a traditional circular section to a square section, a triangular section or even other sections, and the hydraulic cylinder can adapt to more limited space or environments with constraints on the placement and use of the hydraulic cylinder.

Specifically, the invention provides the following technical scheme: the invention provides a zero-leakage hydraulic cylinder which comprises a cylinder barrel, a piston, a rodless cavity oil bag and a rod cavity oil bag, wherein the piston is arranged in the cylinder barrel; the piston, the rodless cavity oil bag and the rod cavity oil bag are all arranged inside the cylinder barrel, and the piston is connected with the inner wall of the cylinder barrel in a sliding mode; a first oil through hole and a second oil through hole are formed in the side wall of the cylinder barrel; a first opening is formed in the side wall of the first surface of the rodless cavity oil bag and connected with the first oil through hole, and a second opening is formed in the side wall of the first surface of the rodless cavity oil bag and connected with the second oil through hole; the first face of the piston is in contact with the second face of the rodless cavity oil pocket, and the second face of the piston is in contact with the second face of the rod cavity oil pocket; a through hole is formed in the middle of the oil bag with the rod cavity in a penetrating mode, a piston rod is arranged in the middle of the second surface of the piston, the piston rod penetrates through the through hole to be connected with an external device, and the oil bag with the rod cavity is connected with the piston rod in a sliding mode; when high-pressure oil is injected into the rodless cavity oil bag, a first surface of the rodless cavity oil bag is in close contact with a bottom cylinder cover of the cylinder barrel, a second surface of the rodless cavity oil bag is in close contact with a first surface of the piston, and the side wall of the rodless cavity oil bag is in close contact with the inner wall of the cylinder barrel; when high-pressure oil is injected into the oil bag with the rod cavity, the second surface of the oil bag with the rod cavity is in close contact with the second surface of the piston, the side wall of the oil bag with the rod cavity is in close contact with the inner wall of the cylinder barrel, the first surface of the oil bag with the rod cavity is in close contact with the top cylinder cover of the cylinder barrel, and the outer surface of the oil bag with the rod cavity in the through hole is in close contact with the side wall of the piston rod.

Further, the cylinder barrel is of a hollow thin-wall barrel-shaped structure with flanges at two ends, the flanges at the two ends are respectively provided with bolt holes, the flanges at the two ends are respectively a first flange and a second flange, the first flange of the cylinder barrel is connected with a bottom cylinder cover, and the second flange of the cylinder barrel is connected with a top cylinder cover; the periphery of the bottom cylinder cover is provided with bolt holes, the periphery of the bottom cylinder cover is fixedly connected with a first flange of a cylinder barrel through bolts, a first surface of the bottom cylinder cover is provided with a spherical hinge, a second surface of the bottom cylinder cover is provided with a first sealing strip and a second sealing strip, a first side wall strip of the first sealing strip is connected with the bottom cylinder cover, a space between opposite surfaces of the first sealing strip and the second sealing strip is a first limiting groove, the first limiting groove is used for limiting the moving position of a piston, a bottom sealing groove is formed in the side wall of the outer side of the second sealing strip, a second side wall strip of the first sealing strip is provided with a first opening, and the first opening is used for protecting the first opening; the piston rod is provided with a piston rod, a top cylinder cover is arranged on the top cylinder cover, a center hole is formed in the center of the top cylinder cover, a center hole sealing groove is formed in the center hole, a center hole sealing assembly used for preventing external dust from entering the inside of the cylinder barrel is arranged in the center hole sealing groove, a groove for distinguishing machining surfaces and non-machining surfaces is formed in the first surface of the top cylinder cover, a third sealing strip and a fourth sealing strip are arranged on the second surface of the top cylinder cover, the first side face of the third sealing strip is connected with the top cylinder cover, a second limiting groove is formed in the space between the opposite faces of the third sealing strip and the fourth sealing strip, the second limiting groove is used for limiting the moving position of a piston, a top sealing groove is formed in the outer side wall of the fourth sealing strip, a second opening is formed in the second side face of the third sealing strip, and the second opening is used for protecting the second opening.

Further, a first limiting snap ring is arranged on the peripheral side wall of the first surface of the piston, the first limiting snap ring is matched with a first limiting groove of the bottom cylinder cover and used for limiting the displacement of the piston, a third opening is arranged on the first limiting snap ring, and the third opening is used for preventing the first limiting snap ring from contacting with the first oil through hole; the piston is characterized in that a second limiting snap ring is arranged on the peripheral side wall of the second face of the piston and matched with a second limiting groove in the top cylinder cover to limit the position movement of the piston, a fourth opening is arranged on the second limiting snap ring and used for preventing the second limiting snap ring from contacting with the second oil through hole, and the piston is in sliding connection with the cylinder barrel.

Furthermore, a joint of the first opening and the first oil through hole and a joint of the second opening and the second oil through hole are both provided with double-sided thread rings, and the double-sided thread rings are connected with pipe joints; the first opening and the second opening both penetrate through the pipe joint.

Furthermore, the surface of the first limiting snap ring and the surface of the second limiting snap ring are respectively matched with the surface of the first limiting groove on the bottom cylinder cover and the surface of the second limiting groove on the top cylinder cover and are both arranged to be wedge-shaped planes.

Further, the diameter of the rodless cavity oil bag is larger than that of the first sealing belt of the bottom cylinder cover, and the diameter of the section of the rod cavity oil bag is larger than that of the third sealing belt of the top cylinder cover.

Furthermore, the first notch, the second notch, the third notch and the fourth notch are arranged on the same straight line.

Furthermore, the surfaces of the contact positions of the oil bag with the rod cavity and the oil bag without the rod cavity and the cylinder barrel are of a corrugated pipe structure.

Further, bolt holes on flanges of the first end and the second end of the cylinder barrel are uniformly distributed along the circumferential direction;

and internal threads are arranged on the inner surfaces of the first oil through hole and the second oil through hole.

Compared with the prior art, the invention has the following beneficial effects:

1. the zero-leakage hydraulic cylinder solves the problem that the strict transmission ratio of the hydraulic cylinder is difficult to realize due to leakage, improves the control precision of the hydraulic cylinder by arranging the rodless cavity oil bag and the rod cavity oil bag, and ensures that the motion deviation of the hydraulic cylinder is only caused by the change of the compression volume of oil liquid; the double-bag type hydraulic cylinder has the advantages that the double-bag type hydraulic cylinder body can effectively prevent the side leakage of oil, so that the oil compression ratio is obtained through calculation, the accurate control of the movement precision of the hydraulic cylinder is realized, the possibility that the environment is polluted due to the leakage of the hydraulic cylinder, resources are wasted, and major accidents are caused by the combustion of the oil is reduced, the phenomenon of more serious leakage caused by the temperature rise of the system during working and the reduction of the viscosity of the oil is avoided, the technical problem that the leakage is more and more caused by the pressure increase of the hydraulic cylinder at the present stage is solved, and the high-pressure and ultrahigh-pressure of the hydraulic cylinder are more easily realized.

2. According to the zero-leakage hydraulic cylinder, the double bags greatly reduce the high machining precision requirement on the inner wall of the cylinder barrel of the hydraulic cylinder and the side surface of the piston to achieve high sealing performance, so that the machining and manufacturing cost of the hydraulic cylinder is greatly reduced, and the structure of the hydraulic cylinder is simplified.

3. The zero-leakage hydraulic cylinder provided by the invention effectively solves the leakage problem due to the arrangement of the double bags, so that the zero-leakage hydraulic cylinder is not limited to a cylinder with good sealing performance any more, and the section of the zero-leakage hydraulic cylinder can be changed from a round shape to a square shape, a triangular shape or other shapes, so that the zero-leakage hydraulic cylinder can adapt to more limited spaces or environments with restriction on the arrangement and use of the hydraulic cylinder.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view in half section of the overall structure of the present invention;

FIG. 2 is a schematic view of the cylinder structure of the present invention;

FIG. 3 is a schematic view of the bottom head construction of the present invention;

FIG. 4 is a schematic view of the top head construction of the present invention;

FIG. 5 is a schematic view of the piston and piston rod configuration of the present invention;

FIG. 6 is a schematic view of a sucker rod chamber oil bladder configuration of the present invention;

FIG. 7 is an enlarged view of a double-sided thread turn construction of the present invention;

FIG. 8 is a schematic view of the overall configuration of the rod chamber oil bladder of the present invention in half section when filled with high pressure oil;

FIG. 9 is a schematic view of the overall configuration of the rodless chamber oil bladder of the present invention in half section when filled with high pressure oil;

FIG. 10 is a schematic illustration of an example of a hydraulic cylinder configuration to which the zero leakage technique of the present invention is adapted 1;

FIG. 11 is a schematic illustration of an example of a cylinder configuration to which the zero leakage technique of the present invention is adapted 2.

Reference numerals: the cylinder 1, the first flange 11, the second flange 12, the first oil passing hole 13, the second oil passing hole 14, the first flange bolt hole 15 of the cylinder, the second flange bolt hole 16 of the cylinder, the bottom cylinder head 2, the spherical hinge 21, the first sealing band 22, the bottom sealing groove 221, the first limiting groove 222, the first notch 223, the bottom sealing assembly 23, the second sealing band 24, the peripheral bolt hole 25 of the bottom cylinder head, the top cylinder head 3, the center hole 31, the center hole sealing groove 311, the center hole sealing assembly 32, the groove 33 for distinguishing the machined surface from the machined surface, the third sealing band 34, the second limiting groove 341, the top sealing groove 342, the second notch 343, the top sealing assembly 35, the fourth sealing band 36, the peripheral bolt hole 37 of the top cylinder head, the piston 4, the first limiting snap ring 41, the third notch 411, the second limiting snap ring 42, the fourth notch 421, the piston rod 5, the threaded section 51, the rodless cavity oil bag 6, the first opening 61, the rod cavity oil bag 7, the second opening 71, the through hole 72, the double-face ring 8 and the hexagonal flange 81.

Detailed Description

The technical solution of the present invention will be clearly and completely described by the following detailed description. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

As shown in fig. 1, a zero-leakage hydraulic cylinder comprises a cylinder barrel 1, a piston 4, a rodless cavity oil bag 6 and a rod cavity oil bag 7; the piston 4, the rodless cavity oil bag 6 and the rod cavity oil bag 7 are all arranged inside the cylinder barrel 1, and the piston 4 is connected with the inner wall of the cylinder barrel 1 in a sliding manner; a first oil through hole 13 and a second oil through hole 14 are formed in the side wall of the cylinder barrel 1, and the openings of the rodless cavity oil bag 6 and the rod cavity oil bag 7 are respectively connected with the first oil through hole 13 and the second oil through hole 14; the first surface of the piston 4 is contacted with the rodless cavity oil bag 6, and the second surface of the piston 4 is contacted with the rod cavity oil bag 7; the second surface of the rodless cavity oil bag 6 is in contact with the first surface of the piston 4, a first opening 61 is formed in the side wall of the first surface of the rodless cavity oil bag 6, the first opening 61 is connected with a first oil through hole 13, a through hole 72 penetrating through the middle of the rod cavity oil bag 7 is formed in the middle of the rod cavity oil bag 7, the piston rod 5 penetrates through the through hole 72 to be connected with an external device, a second opening 71 is formed in the side wall of the first surface of the rod cavity oil bag 7, and the second opening 71 is connected with a second oil through hole 14;

when high-pressure oil is injected into the rodless cavity oil bag 6, the first surface of the rodless cavity oil bag 6 is in close contact with the bottom cylinder cover 2, the second surface of the rodless cavity oil bag 6 is in close contact with the first surface of the piston 4, and the side wall of the rodless cavity oil bag 6 is in close contact with the inner wall of the cylinder barrel 1.

When high-pressure oil is injected into the rod cavity oil bag 7, the second surface of the rod cavity oil bag 7 is in close contact with the second surface of the piston 4, the side surface of the rod cavity oil bag 7 is in close contact with the inner wall of the cylinder barrel 1, the first surface of the rod cavity oil bag 7 is in close contact with the top cylinder cover 3, the outer surface of the rod cavity oil bag 7 in the through hole 72 is in close contact with the side wall of the piston rod 5, and the rod cavity oil bag 7 is in sliding connection with the piston rod 5.

The cylinder barrel 1 is of a hollow thin-walled cylinder structure with flanges at two ends, the flanges at the two ends are provided with bolt holes, the flanges at the two ends comprise a first flange 11 of the cylinder barrel and a second flange 12 of the cylinder barrel, the first flange 11 of the cylinder barrel is connected with a bottom cylinder cover 2, and the second flange 12 of the cylinder barrel is connected with a top cylinder cover 3.

The periphery of the bottom cylinder cover 2 is provided with a bolt hole, the periphery of the bottom cylinder cover 2 is fixedly connected with the first flange 11 of the cylinder barrel through a bolt, the first surface of the bottom cylinder cover 2 is provided with a spherical hinge 21, the second surface of the bottom cylinder cover 2 is provided with a first sealing strip 22 and a second sealing strip 24, a first side wall strip of the first sealing strip 22 is connected with the bottom cylinder cover 2, a space between opposite surfaces of the first sealing strip 22 and the second sealing strip 24 is a first limiting groove 222, the surface of the first limiting groove 222 is wedge-shaped and can be in good fit contact with a wedge-shaped surface of a first limiting snap ring 41 on the piston 4 to limit the movement of the piston 4, the piston 4 is prevented from excessively extruding the rodless cavity oil sac 6, the design of the wedge-shaped surface has a buffering effect, the collision between the piston 4 and the bottom cylinder cover 2 is avoided, a first notch 223 is formed in a second side wall strip of the first sealing strip 22 and used for protecting a first opening 61, a bottom sealing groove 24 is formed in an outer side wall of the bottom sealing strip 221, and a bottom sealing groove is provided with a bottom sealing component 23 used for preventing external dust from entering the inside of the cylinder barrel 1.

The first face of top cylinder cap is equipped with the groove of distinguishing processing and non-processing surface, and the groove of distinguishing processing and non-processing surface can reduce machining area, reduces the processing cost, shortens process time.

The center of the top cylinder cover 3 is provided with a center hole 31 through which a piston rod 5 passes, a center hole sealing groove 311 is arranged in the center hole 31, a center hole sealing assembly 32 used for preventing external dust from entering the cylinder barrel 1 is arranged in the center hole sealing groove 311, a first surface of the top cylinder cover is provided with a groove 33 used for distinguishing machined surfaces from non-machined surfaces, a second surface of the top cylinder cover 3 is provided with a third sealing strip 34 and a fourth sealing strip 36, a first side surface strip of the third sealing strip 34 is connected with the top cylinder cover 3, a space between opposite surfaces of the third sealing strip 34 and the fourth sealing strip 36 is a second limiting groove 341, the second limiting groove 341 is used for limiting the moving position of the piston 4, the surface of the second limiting groove 341 is wedge-shaped, can be in good fit contact with the wedge-shaped surface of a second limiting snap ring 42 on the piston 4 to limit the displacement of the piston 4, the rod cavity oil bag 7 is prevented from being excessively extruded by the piston 4, the design of the wedge-shaped surface has a buffering effect, the violent collision between the piston 4 and the top cylinder barrel 3 is avoided, a top sealing groove 342 is provided with a top sealing groove 35 used for preventing external dust from entering the top sealing assembly 1, and a second side surface 343 is provided with a second limiting snap ring 343, and an oil hole opening 343.

The first limiting snap ring 41 is arranged on the peripheral side wall of the first surface of the piston 4, the first limiting snap ring 41 can be matched with the first limiting groove 222 of the bottom cylinder cover 2 and used for limiting the position movement of the piston 4, a third opening 411 is arranged on the first limiting snap ring 41, and the third opening 411 can prevent the first limiting snap ring 41 from contacting with the first oil through hole 13. The surface of the first limiting snap ring 41 is a wedge surface that can be well matched with the surface of the first limiting groove 222, so as to limit the displacement of the piston 4.

A piston rod 5 is arranged in the middle of the second surface of the piston 4, a second limiting clamping ring 42 is arranged on the peripheral side wall of the second surface of the piston 4, the second limiting clamping ring 42 can be matched with a second limiting groove 341 on the top cylinder cover 3 and is used for limiting the displacement of the piston 4, a fourth opening 421 is arranged on the second limiting clamping ring 42, the second limiting clamping ring 42 can be prevented from contacting with the second oil through hole 14 by the fourth opening 421, and the piston 4 is in sliding connection with the cylinder barrel 1; the first end of the piston rod 5 is connected with the middle part of the second surface of the piston 4, the second end of the piston rod 5 is provided with a thread structure, the second end of the piston rod 5 penetrates through the rod cavity oil bag 7 and the top cylinder cover 3, and the thread structure is connected with an external workpiece.

The joint of the first opening 61 and the first oil through hole 13 and the joint of the second opening 71 and the second oil through hole 14 are both provided with double-sided thread rings 8, the double-sided thread rings 8 fixedly connect the first opening 61 and the first oil through hole 13 through thread screwing and extrusion, and the double-sided thread rings 8 fixedly connect the second opening 71 and the second oil through hole 14 through thread screwing and extrusion; the double-side thread ring 8 comprises a screw head and a screw rod, the screw head and the screw rod are both of a hollow structure, the screw rod is connected with the center position of the screw head, threads are arranged on the inner surface and the outer surface of the side wall of the screw rod, the outer surface of the double-side thread ring 8 is fixedly connected with the oil through hole through threads, the inner surface of the double-side thread ring 8 is fixedly connected with the pipe joint through threads, the oil inlet pipeline and the oil return pipeline all penetrate through the pipe joint, the screw head is a hexagonal flange 81, and the hexagonal flange 81 facilitates the assembly and disassembly of the double-side thread ring 8.

When the piston 4 is in a working state and the first limiting snap ring 41 is in contact with the first limiting groove 222, the first limiting snap ring 41 and the first limiting groove 222 can protect the rodless cavity oil bag 6, so that the piston 4 cannot excessively extrude the rodless cavity oil bag 6; when the second limit snap ring 42 contacts the second limit groove 341, the second limit snap ring 42 and the second limit groove 341 can protect the rod cavity oil bag 7, have a buffering effect and avoid violent impact, and meanwhile, the surface of the second limit snap ring 42 and the surface of the second limit groove 341 have wedge surfaces which are matched with each other, so that the displacement of the piston 4 can be limited.

The surface of the first limit snap ring 41 and the surface of the second limit snap ring 42 are respectively matched with the surface of the first limit groove 222 on the bottom cylinder cover 2 and the surface of the second limit groove 341 on the top cylinder cover 3 to form wedge-shaped planes.

The surface of the first limiting clamping ring 41 is provided with a wedge-shaped plane matched with the surface of the first limiting groove 222 on the bottom cylinder cover; the surface of the second limit snap ring 42 is provided with a wedge-shaped plane matched with the surface of the second limit groove 341 on the top cylinder cover.

The section diameters of the rodless chamber oil bag 6 and the rod chamber oil bag 7 are respectively larger than the diameters of the bottom cylinder cover first sealing belt 22 and the top cylinder cover third sealing belt 34, so that the rodless chamber oil bag 6 and the rod chamber oil bag 7 are prevented from being squeezed when the piston 4 moves.

The first notch 223, the second notch 343, the third notch 411 and the fourth notch 421 are arranged on the same straight line, so that the first limiting clamping ring 41 and the second limiting clamping ring 42 are prevented from extruding the rodless cavity oil bag 6 and the rod cavity oil bag 7 in the moving process.

The surfaces of the contact positions of the oil bag 7 with the rod cavity and the oil bag 6 without the rod cavity and the cylinder barrel 1 are of corrugated pipe structures, and the corrugated pipe structures can play a role in guiding the oil bag 7 with the rod cavity and the oil bag 6 without the rod cavity when working, so that the oil bag 7 with the rod cavity and the oil bag 6 without the rod cavity can be more smooth when working.

Bolt holes on flanges at the first end and the second end of the cylinder barrel 1 are uniformly distributed along the circumferential direction; the inner surfaces of the first oil through hole 13 and the second oil through hole 14 are provided with internal threads.

As shown in fig. 2, a first flange 11 and a second flange 12 are respectively disposed at two ends of the cylinder tube 1, a plurality of cylinder tube first flange bolt holes 15 and cylinder tube second flange bolt holes 16 are respectively and uniformly distributed on the surfaces of the first flange 11 and the second flange 12, the cylinder tube first flange bolt holes 15 and the cylinder tube second flange bolt holes 16 are respectively and fixedly connected with the bottom cylinder head peripheral bolt holes 25 and the top cylinder head peripheral bolt holes 37 through bolts, and a first oil through hole 13 and a second oil through hole 14 are respectively disposed at two ends of the side surface of the cylinder tube 1.

As shown in fig. 3, eight cylinder barrel first flange bolt holes 15 are uniformly arranged on the periphery of the bottom cylinder cover 2, a ball hinge 21 is arranged on a first surface of the bottom cylinder cover 2, a first sealing strip 22 and a second sealing strip 24 are arranged on a second surface of the bottom cylinder cover 2, a first side wall strip of the first sealing strip 22 is connected with the bottom cylinder cover 2, a space between opposite surfaces of the first sealing strip 22 and the second sealing strip 24 is a first limit groove 222, the surface of the first limit groove 222 is wedge-shaped and can be in good fit contact with a wedge-shaped surface of a first limit snap ring 41 on a piston 4 to limit the movement of the piston 4, the piston 4 is prevented from excessively extruding a rodless cavity oil bag 6, the wedge-shaped surface has a buffering effect, the piston 4 and the bottom cylinder cover 2 are prevented from being strongly impacted, a first notch 223 is formed in a second side wall strip of the first sealing strip 22, the first notch 223 is used for protecting a first opening 61, a bottom sealing groove 221 is formed in an outer side wall of the second sealing strip 24, the outer side of the second sealing strip 24 is connected with an inner wall of the first end, and a bottom cylinder barrel assembly 23 for preventing external dust from entering into the bottom sealing groove 221.

As shown in fig. 4, eight cylinder second flange bolt holes 16 are uniformly formed in the periphery of the top cylinder head 3, a center hole 31 for the piston rod 5 to pass through is formed in the center of the top cylinder head 3, a center hole sealing groove 311 is formed in the center hole 31, a center hole sealing assembly 32 for preventing external dust from entering the cylinder 1 is arranged in the center hole sealing groove 311, a groove 33 for distinguishing machined surfaces from non-machined surfaces is formed in the first surface of the top cylinder head, a third sealing strip 34 and a fourth sealing strip 36 are arranged on the second surface of the top cylinder head, a first side surface of the third sealing strip 34 is connected with the top cylinder head 3, a space between opposite surfaces of the third sealing strip 34 and the fourth sealing strip 36 is a second limiting groove 341, and the second limiting groove 341 is used for limiting the moving position of the piston 4, the surface of the second limit groove 341 is wedge-shaped, and can be in good fit contact with the wedge-shaped surface of the second limit snap ring 42 on the piston 4, so as to limit the displacement of the piston 4, prevent the piston 4 from excessively extruding the rod cavity oil bag 7, and the design of the wedge-shaped surface has a buffering effect, prevent the strong impact of the piston 4 and the top cylinder cover 3, a top sealing groove 342 is formed on the outer side wall of the fourth sealing belt 36, the outer wall of the fourth sealing belt 36 is connected with the inner wall of the second end of the cylinder barrel 1, a top sealing component 35 for preventing external dust from entering the cylinder barrel 1 is arranged in the top sealing groove 342, a second notch 343 is formed on the second side surface of the third sealing belt 34, and the second notch 343 can prevent the second limit snap ring 42 from contacting the second oil through hole 14

As shown in fig. 5, the piston 4 is slidably connected to the cylinder barrel 1, a first limiting snap ring 41 is disposed on a peripheral side wall of a first surface of the piston 4, the first limiting snap ring 41 can be matched with a first limiting groove 222 of the bottom cylinder head 2 to limit the position movement of the piston 4, and has a buffering effect when the first limiting snap ring 41 contacts with the first limiting groove 222, a third opening 411 is disposed on the first limiting snap ring 41, and the third opening 411 can prevent the first limiting snap ring 41 from contacting with the first oil through hole 13. The surface of the first limiting snap ring 41 is a wedge-shaped surface which can be well matched with the surface of the first limiting groove 222, so that the displacement of the piston 4 is limited, the piston 4 is prevented from excessively extruding the rodless cavity oil bag 6, and the piston 4 and the bottom cylinder cover 2 are prevented from being strongly collided; the middle part of the second surface of the piston 4 is provided with a piston rod 5, the peripheral side wall of the second surface of the piston 4 is provided with a second limiting snap ring 42, the second limiting snap ring 42 can be matched with a second limiting groove 341 on the top cylinder cover 3 and is used for limiting the displacement of the piston 4 and preventing the piston 4 from excessively extruding a rod cavity oil bag 7, the second limiting snap ring 42 is provided with a fourth opening 421, the fourth opening 421 can prevent the second limiting snap ring 42 from contacting with the second oil through hole 14, and the second limiting snap ring 42 has a buffering effect when contacting with the second limiting groove 341 and can prevent the piston 4 from strongly colliding with the top cylinder cover 3; the first end of the piston rod 5 is connected with the middle part of the second surface of the piston 4, the second end of the piston rod 5 is provided with a thread structure, the second end of the piston rod 5 penetrates through the rod cavity oil bag 7 and the top cylinder cover 3, and the thread structure is connected with an external workpiece.

As shown in fig. 6, a second opening 71 is provided on a side surface of the rod chamber oil bag 7 near one end of the top cylinder cover 3, a through hole 72 is provided in the middle of the rod chamber oil bag 7, a side wall of the rod chamber oil bag 7 is of a bellows structure, which plays a role in radial guiding and axial guiding when the rod chamber oil bag 7 extends and retracts, and a length of a material of the rod chamber oil bag 7 following the above design rule should be slightly greater than a height of the third sealing belt 34 of the top cylinder cover, so as to prevent the piston 4 from extruding the rod chamber oil bag 7 when moving.

As shown in fig. 7, both the inner surface and the outer surface of the double-sided thread ring 8 are provided with threads, the threads on the inner surface of the double-sided thread ring 8 are connected with the rod cavity oil bag 7 or the rodless cavity oil bag 6 through external pipe joint threads, the threads on the outer surface of the double-sided thread ring 8 are in threaded connection with the first oil through hole 13 or the second oil through hole 14, one end of the double-sided thread ring 8 is provided with a hexagonal flange 81, and the hexagonal flange 81 facilitates the assembly and disassembly of the double-sided thread ring 8.

As shown in fig. 8 to 9, the structure diagrams are respectively when the rod cavity oil bag 7 injects high pressure oil and the rodless cavity injects high pressure oil, and the piston 4 moves to the end point; when high-pressure oil is injected into the rod cavity oil bag 7, the piston 4 moves to the bottom cylinder cover 2, the first limiting clamping ring 41 is in contact with the first limiting groove 222, the rodless cavity oil bag 6 is compressed, the rod cavity oil bag 7 is expanded, the side face of the rod cavity oil bag 7 is in close contact with the inner wall of the cylinder barrel 1, the first face of the rod cavity oil bag is in close contact with the second face of the top cylinder cover, the second face of the rod cavity oil bag is in close contact with the second face of the piston 4, and the hydraulic rod retracts; when the rodless cavity oil bag 6 is filled with high-pressure oil, the piston 4 moves to the position of the top cylinder cover 3, the second limiting clamping ring 42 is in contact with the second limiting groove 341, the rodless cavity oil bag 6 is stretched, the rod cavity oil bag 7 is compressed, the side face of the rodless cavity oil bag 6 is in close contact with the inner wall of the cylinder barrel 1, the first face of the rodless cavity oil bag 6 is in close contact with the second face of the bottom cylinder cover 2, the second face of the rodless cavity oil bag 6 is in close contact with the first face of the piston 4, and the hydraulic rod extends out.

As shown in fig. 10 to 11, since the zero-leakage hydraulic cylinder provided by the present invention solves the problem of leakage of the existing hydraulic cylinder, the technology applied to the zero-leakage hydraulic cylinder provided by the present invention indirectly breaks through the limitation that the traditional hydraulic cylinder has a cylindrical shape, and through the demonstration of examples of an angular hydraulic cylinder and a square hydraulic cylinder, it is described herein that the technology applied to the zero-leakage hydraulic cylinder provided by the present invention can change the shape of the hydraulic cylinder by changing the shape and the guiding direction of the internal oil bag.

The method comprises the following specific operation steps:

the first oil through hole 13, the first opening 61 and the double-sided thread ring 8 are fixedly connected through threads, the second oil through hole 14, the second opening 71 and the double-sided thread ring 8 are fixedly connected through threads, a first flange 11 and a second flange 12 are arranged at two ends of the cylinder barrel 1, the first flange 11 is fixedly connected with the bottom cylinder cover 2 through bolts, the second flange 12 is fixedly connected with the top cylinder cover 3 through bolts, the piston 4 is arranged in the cylinder barrel 1 and is in sliding connection with the cylinder barrel 1, the first surface of the piston 4 is in tight contact with the second surface of the rodless cavity oil bag 6, the second surface of the piston 4 is in tight contact with the second surface of the rodless cavity oil bag, the piston rod 5 extends out of the cylinder barrel 1 through a through hole 72 of the rodless cavity oil bag and a central hole 31 of the top cylinder cover 3, a thread section 51 is arranged at the second end of the piston rod 5 for connecting a workpiece to do work outwards, and when high-pressure oil is injected into the rodless cavity oil bag 6, the first surface, the side surface and the second surface of the rodless cavity oil bag 6 are respectively in close contact with the second surface of the bottom cylinder cover, the inner wall of the cylinder barrel and the first surface of the piston 4, when high-pressure oil is injected into the rodless cavity oil bag 7, the first surface, the side surface and the second surface of the rodless cavity oil bag are respectively in close contact with the second surface of the top cylinder cover 3, the inner wall of the cylinder barrel and the second surface of the piston 4, meanwhile, the material thicknesses of the rodless cavity oil bag 6 and the rodless cavity oil bag 7 are periodically different and regularly arranged, the material thicknesses of the side surfaces of the first surface of the rodless cavity oil bag 6 and the first surface of the rodless cavity oil bag at one end are circumferentially and periodically changed and axially consistent, the lengths of the materials of the rodless cavity oil bag 6 and the rodless cavity oil bag 7 following the design rules are slightly larger than the heights of the first sealing belt 22 of the bottom cylinder cover and the third sealing belt 34 of the top cylinder cover respectively, and the material thicknesses of the side surfaces of the second surface of the rodless cavity oil bag are axially and periodically changed, the circumference is consistent, and the materials of the second surface of the rodless cavity oil pocket 6 and the end where the second surface of the rod cavity oil pocket is located are distributed uniformly in a staggered manner according to the radius from the second surface of the oil pocket to the first surface.

When the hydraulic cylinder works, the first oil through hole 13 and the second oil through hole 14 in the cylinder barrel 1 are connected into a hydraulic system loop, when high-pressure oil is injected into the rodless cavity oil bag 6 through the first oil through hole 13 by the hydraulic system, the oil pressure in the rodless cavity oil bag 6 is increased, the piston 4 moves towards the rod cavity oil bag 7, the rod cavity oil bag 7 is extruded at the same time, low-pressure oil in the rod cavity oil bag 7 flows out through the second oil through hole 14, at the moment, the hydraulic rod extends out, a workpiece connected with the threaded section 51 applies work outwards until the second limiting snap ring 42 is in contact with the second limiting groove 341, the piston 4 stops moving, and the extending stroke of the hydraulic rod is terminated; when a hydraulic system injects high-pressure oil into the rod cavity oil bag 7 through the second oil through hole 14, the oil pressure in the rod cavity oil bag 7 rises, the piston 4 moves towards the direction of the rodless cavity oil bag 6 and simultaneously extrudes the rodless cavity oil bag 6, low-pressure oil in the rodless cavity oil bag 6 flows out through the first oil through hole 13, the hydraulic rod retracts at the moment until the first limiting snap ring 41 is contacted with the first limiting groove 222, the piston 4 stops moving, and the retraction stroke of the hydraulic rod is terminated.

The above-mentioned embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solution of the present invention by those skilled in the art should fall within the protection scope defined by the claims of the present invention without departing from the spirit of the present invention.

Claims

1. A zero-leakage hydraulic cylinder is characterized by comprising a cylinder barrel, a piston, a rodless cavity oil bag and a rod cavity oil bag; the piston, the rodless cavity oil bag and the rod cavity oil bag are all arranged inside the cylinder barrel, and the piston is connected with the inner wall of the cylinder barrel in a sliding mode; a first oil through hole and a second oil through hole are formed in the side wall of the cylinder barrel; a first opening is formed in the side wall of the first surface of the rodless cavity oil bag and connected with the first oil through hole, and a second opening is formed in the side wall of the first surface of the rodless cavity oil bag and connected with the second oil through hole;

the first face of the piston is in contact with the second face of the rodless cavity oil pocket, and the second face of the piston is in contact with the second face of the rod cavity oil pocket; a through hole is formed in the middle of the oil bag with the rod cavity in a penetrating mode, a piston rod is arranged in the middle of the second surface of the piston, the piston rod penetrates through the through hole to be connected with an external device, and the oil bag with the rod cavity is connected with the piston rod in a sliding mode;

when high-pressure oil is injected into the rodless cavity oil bag, the first surface of the rodless cavity oil bag is in close contact with the bottom cylinder cover of the cylinder barrel, the second surface of the rodless cavity oil bag is in close contact with the first surface of the piston, and the side wall of the rodless cavity oil bag is in close contact with the inner wall of the cylinder barrel;

when high-pressure oil is injected into the oil bag with the rod cavity, the second surface of the oil bag with the rod cavity is in close contact with the second surface of the piston, the side wall of the oil bag with the rod cavity is in close contact with the inner wall of the cylinder barrel, the first surface of the oil bag with the rod cavity is in close contact with the top cylinder cover of the cylinder barrel, and the outer surface of the oil bag with the rod cavity in the through hole is in close contact with the side wall of the piston rod;

the cylinder barrel is a hollow thin-walled cylinder structure with flanges at two ends, the flanges at two ends are both provided with bolt holes, the flanges at two ends are respectively a first flange of the cylinder barrel and a second flange of the cylinder barrel, the first flange of the cylinder barrel is connected with a bottom cylinder cover, and the second flange of the cylinder barrel is connected with a top cylinder cover;

the periphery of the bottom cylinder cover is provided with bolt holes, the periphery of the bottom cylinder cover is fixedly connected with a first flange of a cylinder barrel through bolts, a first surface of the bottom cylinder cover is provided with a spherical hinge, a second surface of the bottom cylinder cover is provided with a first sealing strip and a second sealing strip, a first side wall strip of the first sealing strip is connected with the bottom cylinder cover, a space between opposite surfaces of the first sealing strip and the second sealing strip is a first limiting groove, the first limiting groove is used for limiting the moving position of a piston, a bottom sealing groove is formed in the side wall of the outer side of the second sealing strip, a first opening is formed in a second side wall strip of the first sealing strip, and the first opening is used for protecting the first opening;

the utility model discloses a piston, including top cylinder cap, piston rod, top cylinder cap, first sealing strip, second sealing strip, piston rod and piston rod, top cylinder cap center department is equipped with the confession the centre bore that the piston rod passes through, the inside centre bore seal groove that is equipped with of centre bore, be equipped with in the centre bore seal groove and be used for preventing that external dust from getting into the inside centre bore seal assembly of cylinder, the first face of top cylinder cap is equipped with the groove of distinguishing processing and non-processing surface, the second face of top cylinder cap is equipped with third sealing strip and fourth sealing strip, the first side wall area of third sealing strip with the top cylinder cap is connected, the third sealing strip with space between the opposite face of fourth sealing strip is the second spacing groove, the second spacing groove is used for limiting piston shift position, the top seal groove has been seted up on the outside lateral wall of fourth sealing strip, the second opening has been seted up on the second side wall area of third sealing strip, the second opening is used for protecting the second opening.

2. The zero-leakage hydraulic cylinder according to claim 1, characterized in that a first limiting snap ring is arranged on the peripheral side wall of the first surface of the piston, the first limiting snap ring is matched with a first limiting groove of a bottom cylinder cover and used for limiting the displacement of the piston, a third notch is arranged on the first limiting snap ring, and the third notch is used for preventing the first limiting snap ring from contacting with the first oil through hole;

the piston is characterized in that a second limiting snap ring is arranged on the peripheral side wall of the second face of the piston and matched with a second limiting groove in the top cylinder cover to limit the position movement of the piston, a fourth opening is arranged on the second limiting snap ring and used for preventing the second limiting snap ring from contacting with the second oil through hole, and the piston is in sliding connection with the cylinder barrel.

3. The zero-leakage hydraulic cylinder according to claim 1, wherein a joint of the first opening and the first oil through hole and a joint of the second opening and the second oil through hole are provided with double-sided thread rings to which a pipe joint is connected; the first opening and the second opening both penetrate through the pipe joint.

4. The zero-leakage hydraulic cylinder of claim 2, wherein the first and second retaining snap ring surfaces are mated with and disposed as wedge-shaped surfaces in the first and second retaining groove surfaces on the bottom and top cylinder heads, respectively.

5. The zero-leakage hydraulic cylinder according to claim 4, wherein the rodless chamber oil gallery has a cross-sectional diameter greater than a diameter of the bottom head first sealing band and the rod chamber oil gallery has a cross-sectional diameter greater than a diameter of the top head third sealing band.

6. The zero-leak hydraulic cylinder according to claim 2, wherein the first gap, the second gap, the third gap and the fourth gap are aligned.

7. The zero-leakage hydraulic cylinder as recited in claim 1, wherein the surfaces of the rod chamber and rodless chamber pockets in contact with the cylinder barrel are of a bellows configuration.

8. The zero-leakage hydraulic cylinder as claimed in claim 1, wherein the bolt holes on the flanges of the first end and the second end of the cylinder barrel are evenly distributed along the circumferential direction; and internal threads are arranged on the inner surfaces of the first oil through hole and the second oil through hole.