Hydraulic cylinder, sealing assembly for piston rod of hydraulic cylinder and annular disc-shaped check ring

Abstract

A hydraulic cylinder, a seal assembly for a piston rod of a hydraulic cylinder, and an annular disc-shaped retainer ring, the seal assembly including an annular cushion seal having a first axial pressure side configured to face a rod end cavity of the hydraulic cylinder and a second axial sealing side opposite the first axial pressure side, the second axial sealing side configured to face the rod end cavity of the hydraulic cylinder, the first axial pressure side being configured to face the rod end cavity of the hydraulic cylinder, and the second axial sealing side being configured to face the rod end cavity of the hydraulic cylinder. And an annular groove defined in the cylinder head at a rod end of the hydraulic cylinder through which the piston rod passes, adjacent to a first axial side surface of the annular groove. The annular disc-shaped retainer ring is configured to extend along the entire radial extent of the second axial sealing side of the annular cushion seal and is axially positioned between the annular cushion seal and the second axial side surface of the annular groove.

Description

Technical Field

[0001] The utility model relates to a sealing assembly for a hydraulic cylinder, and in particular to a sealing assembly comprising an annular buffer seal and a retaining ring extending along the radial range of a sealing surface of the buffer seal. Background Art

[0002] Many work machines, such as tractors, excavators, loaders and other earth-moving equipment, utilize hydraulic actuators to generate the forces and relative motions required of various parts of the machine to accomplish its tasks. These hydraulic actuators, which include, for example, hydraulic cylinders and fluid motors, typically include two fluid chambers disposed on opposite sides of a movable element. Pressurized fluid is introduced into one of the fluid chambers, which causes the movable element to move relative to the housing of the hydraulic actuator.

[0003] The movable element is usually connected to a work tool or other mechanical part on the work machine by a rod or shaft. Generally, each hydraulic actuator includes a sealing device engaged with the rod or shaft to prevent the pressurized fluid from leaking from the fluid chamber of the hydraulic actuator during use. U.S. Patent No. 6,129,358 describes a one-way rod sealing ring suitable for forming a sealing state, which is one such sealing device for a hydraulic cylinder.

[0004] A sealing arrangement for a hydraulic cylinder may include a series of seals disposed in a cylinder head to engage a shaft or piston rod near an exit point of the piston rod. The cylinder head may include a series of annular grooves or counterbores axially spaced along a radially inner circumferential surface of the cylinder head, the annular grooves being configured to receive each seal.

[0005] When hydraulic cylinders are used in erosive applications, such as hydraulic cylinders used as boom, stick or bucket cylinders on machines such as excavators or large wheel loaders working in applications such as coal mining, annular grooves in the cylinder head adapted to receive various seals may become damaged. Heavy machinery in earth moving operations may also expose hydraulic cylinders used on heavy machinery to move various parts of the machine relative to each other and relative to a working surface to abrasive materials that may pass through one or more seals in an array of seals located between the piston rod and the cylinder head of the hydraulic cylinder. The array of seals may be designed to prevent pressurized hydraulic fluid within the hydraulic cylinder from leaking outwardly between the piston rod and the cylinder head of the hydraulic cylinder, and to prevent contamination of material in the piston rod side cavity (also referred to as a "rod end" cavity or "cap end" cavity) from entering the side of the hydraulic cylinder from the outside of the hydraulic cylinder. In some applications, contaminants may accumulate between the sealing surface of the seal and the surface of the annular groove in the cylinder head adapted to receive the seal. These contaminants can become embedded in the mating surface of the seal and the annular groove in the cylinder head, and over time during cylinder operation, relative movement between the seal with embedded abrasive contaminants and the annular groove may cause a portion of the annular groove (typically formed in the metal material of the cylinder head) to be worn away, thereby creating an undesirable step or gap near the seal, which may ultimately lead to seal failure and cylinder leakage.

[0006] The exemplary embodiments of various sealing assemblies disclosed in the present application and the arrangement of sealing members and guide members disposed in axially spaced annular grooves formed in the radially inner circumferential surface of the cylinder head for slidable engagement with the outer circumferential surface of the piston rod are intended to solve all or some of the above-mentioned problems. Summary of the invention

[0007] On the one hand, the utility model relates to a sealing assembly for a piston rod of a hydraulic cylinder. The sealing assembly includes an annular buffer seal, the annular buffer seal having a first axial pressure side and a second axial sealing side opposite to the first axial pressure side, the first axial pressure side being configured to face the rod end cavity of the hydraulic cylinder and being adjacent to a first axial side surface of an annular groove defined in a cylinder head at the rod end of the hydraulic cylinder, through which the piston rod passes. The sealing assembly also includes an annular disc-shaped retaining ring, the annular disc-shaped retaining ring being configured to extend along the entire radial range of the second axial sealing side of the annular buffer seal and being axially positioned between the annular buffer seal and the second axial side surface of the annular groove, the radial outer circumferential surface of the retaining ring including a chamfered portion facing the second axial side surface of the annular groove.

[0008] On the other hand, the utility model relates to a hydraulic cylinder, which includes a cylinder barrel, a cylinder head located at the rod end of the cylinder barrel, a piston rod passing through the cylinder head at the rod end of the cylinder barrel and configured to move axially relative to the rod end of the cylinder barrel, and a plurality of seals, the plurality of seals are arranged in axially spaced annular grooves, the annular grooves are formed around the inner circumferential surface of the cylinder head at the rod end of the cylinder barrel, and are configured to seal and engage with the piston rod. One of the plurality of seals is a sealing assembly, the sealing assembly includes an annular buffer seal, the annular buffer seal has a first axial pressure side and a second axial sealing side opposite to the first axial pressure side, the first axial pressure side is configured to face the rod end cavity of the hydraulic cylinder, and is assembled adjacent to the first axial side surface of the annular groove, the annular groove is defined in the cylinder head through which the piston rod passes. The sealing assembly also includes an annular disc-shaped retaining ring, the annular disc-shaped retaining ring is configured to extend along the entire radial range of the second axial sealing side of the annular buffer seal and is axially positioned between the annular buffer seal and the second axial side surface of the annular groove, the radial outer circumferential surface of the retaining ring including a chamfered portion facing the second axial side surface of the annular groove.

[0009] On the other hand, the utility model relates to an annular disc-shaped retaining ring, which is configured to be pressed against the entire radial range of the axial sealing side of the annular buffer seal when the retaining ring and the annular buffer seal are installed as a sealing assembly in an annular groove, the annular groove being formed in the inner circumferential surface of the cylinder head at the piston rod end of the hydraulic cylinder for sealing engagement with the piston rod passing through the cylinder head, and the radially outer circumferential surface of the retaining ring includes a chamfered portion of the second axial side surface facing the annular groove. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a partial cross-sectional view of a hydraulic cylinder according to an embodiment of the present utility model, the hydraulic cylinder including an array of seals between a piston rod and a cylinder head of the hydraulic cylinder;

[0011] Figure 2 is a radial cross-sectional view of a section of an annular buffer seal assembly that can be used for sealing between a piston rod and a cylinder head according to an embodiment of the utility model;

[0012] Figure 3 The sealing device for the piston rod and the cylinder cover of the hydraulic cylinder according to the embodiment of the utility model has Figure 2 A partial cross-sectional view of the sealing device of the buffer seal assembly shown;

[0013] Figure 4 It is a partial cross-sectional view of a sealing device for a hydraulic cylinder piston rod and a cylinder cover according to an embodiment of the utility model. DETAILED DESCRIPTION

[0014] With reference to the accompanying drawings, Figure 1An exemplary hydraulic cylinder 10 is shown having a piston rod 12 connected at one axial end to a piston 13 slidably disposed within a cylinder barrel 14. The piston rod 12 is axially movable by a cylinder head 16, which may be bolted to the cylinder barrel 14 by a plurality of bolts or attached to the rod end of the cylinder barrel 14 by other means. The rod end of the cylinder barrel 14 is located at the axial end of the cylinder barrel 14 opposite the blind end or closed cap end 11 of the cylinder barrel 14. As shown in the attached Figure 2-Figure 4 As shown in greater detail in , piston rod 12 is slidably engaged along a circumferential outer periphery of piston rod 12 with an array 18 of annular piston rod seals and wear guides that are axially spaced along a radially inner circumferential surface of cylinder head 16 .

[0015] The annular piston rod seal in the array 18 may be a buffer seal assembly, the buffer seal assembly comprising an annular buffer seal 22 and an annular retaining ring 24, such as Figure 2 and Figure 3 As shown. The buffer seal 22 and the retaining ring 24 can be installed in an operating position in the cylinder head 16 of the hydraulic cylinder 10 and are located in an annular groove 21 extending around the radial inner circumferential surface of the cylinder head 16 for slidable engagement with the piston rod 12 axially movable therein. The hydraulic cylinder 10 is an exemplary embodiment of a hydraulic cylinder for various purposes related to tractors, earth-moving equipment, etc. Some exemplary applications of hydraulic cylinders with buffer seal assemblies of embodiments of the utility model may include hydraulic cylinders for performing one or more operations, where the one or more operations may be such as extending, retracting, lifting, tilting, rotating, and performing other movements of various parts on heavy machinery or other parts of the machine, the various parts on the heavy machinery such as the boom, stick or bucket of an excavator, other parts of the machine such as large wheel loaders, hydraulic mining shovels, large crawler tractors and other equipment.

[0016] like Figure 2 and Figure 3As shown in the exemplary embodiment of , the buffer seal 22 can be an annular elastomeric ring formed of an elastomeric material such as polyurethane or rubber, and is configured to fit within an annular groove 21 formed around the radial inner circumferential surface of the cylinder head 16. The annular buffer seal 22 may include a first axial pressure side and an opposing second axial sealing side, the first axial pressure side being formed with a plurality of continuous axial pressure surfaces 220, 221, 222, and 223 facing the pressurized rod end cavity of the hydraulic cylinder 10, and the opposing second axial sealing side being formed with an axial sealing surface 224, the axial sealing surface 224 facing the exterior of the hydraulic cylinder and being configured to contact the retaining ring 24 in a mating cooperative relationship within the annular groove 21. The first axial pressure side of the annular buffer seal 22 includes a radially inner annular pressure surface 220, which is connected to a radially outer annular pressure surface 223 by two continuous and converging tapered pressure surfaces 221, 222, which together define an annular recess 23 in the first axial pressure side of the buffer seal 22. The buffer seal 22 also includes a radially outer circumferential surface 226 and a radially inner circumferential surface 227, wherein the radially outer circumferential surface 226 is configured to contact the bottom of the annular groove 21, or is placed adjacent to the bottom of the annular groove 21, and the radially inner circumferential surface 227 is configured to contact the piston rod 12 that can move axially in the cylinder head 16. In various exemplary embodiments, as shown in FIG. Figure 3 As shown, the inner circumferential surface 227 configured to contact the piston rod 12 may extend only over a portion of the width of the annular groove 21 and may be formed as the inner circumferential surface of the radially extending lip 342 of the annular buffer seal 22. When fluid pressure is directed into the recess 23, the radially inwardly directed pressure from the expansion of the lip 342 will be concentrated on a smaller circumferential surface area of ​​the piston rod 12, and this lip design can achieve better sealing of the piston rod 12.

[0017] The pressure surfaces 221, 222 may be axially tapered, linear or curved surfaces that converge to define an annular recess 23 in the first axial pressure side of the annular buffer seal 22, wherein the recess 23 separates a radially outer annular leg having the pressure surface 222 and terminating in the axial annular pressure surface 223 from a radially inner annular leg having the pressure surface 221 and the lip 342 and terminating in the axial annular pressure surface 220. Pressure applied to the annular groove 21 may cause the radially outer annular leg to bend radially outward and press against the bottom surface of the annular groove 21, and cause the radially inner annular leg including the lip 342 to bend radially inward and press against the piston rod 12. The radially outer circumferential surface 226 of the buffer seal 22 may be configured with a portion adjacent to or in contact with the bottom of the annular groove 21 along its axial length, and in some cases, when the pressure applied to the annular recess 23 drops below a certain threshold, the portion adjacent to or in contact with the bottom of the annular groove 21 of the radially outer circumferential surface 226 forms a small gap with the bottom of the annular groove 21. Similarly, in various embodiments of the annular buffer seal 22 according to the present invention, the radially inner circumferential surface 227 of the buffer seal 22 may be configured with a portion in contact with the radially outer circumferential surface of the piston rod 12 along its axial length or the entire axial length. In some cases, when the piston rod 12 moves axially relative to the cylinder head 16 and the hydraulic cylinder 10 to extend and retract, the contact portions in the radially outer circumferential surface 226 and / or the radially inner circumferential surface 227 of the buffer seal 22 may be spaced from the bottom of the annular groove 21 and the piston rod 12, respectively, depending on the amount of pressure applied to the annular recess 23 from the pressurized rod end chamber of the hydraulic cylinder 10. A higher pressure above a specific predetermined threshold introduced into the annular recess 23 from the rod end cavity of the hydraulic cylinder 10 may cause one or both of the radially outer annular leg having the pressure surface 222 and the radially inner annular leg having the pressure surface 221 to bend, thereby creating a tighter seal between one or more of the contact portions of the annular buffer seal 22 and the annular groove 21 and / or the piston rod 12.

[0018] like Figure 3As shown, the axial sealing surface 224 of the buffer seal 22 cooperates with the retaining ring 24, and the assembly of the buffer seal 22 and the retaining ring 24 can be cooperatively received in the annular groove 21 formed in the radial inner circumferential surface of the cylinder head 16 of the hydraulic cylinder 10. The retaining ring 24 can be configured to extend along the entire radial extent of the axial sealing surface 224 of the buffer seal 22. The retaining ring 24 can terminate at a chamfered outer circumferential surface 247 having a convex radius R (336) formed on the radial outer edge of the retaining ring 24 facing away from the side of the buffer seal 22 and facing the inner side wall of the annular groove 21. Compared with conventional arrangements, the surface area of ​​the retaining ring 24 in contact with the axial outermost sealing surface 224 of the buffer seal 22 is increased, reducing the contact force at any point along the interface between the retaining ring 24 and the buffer seal 22, thereby reducing any wear caused by friction between the two components, and facilitating the assembly of the retaining ring 24 with the buffer seal 22 in the correct orientation. The convex radius R formed on the radially outer edge of the side of the retaining ring 24 facing away from the buffer seal 22 can avoid the creation of higher stress areas that may be created if the retaining ring 24 is formed with sharp corners or a circumferential edge. In some exemplary embodiments, the radius 336 of the convex radius R can be predetermined based on one or more types of materials used for the buffer seal 22 and the retaining ring 24, the fluid pressure applied to one or both of the buffer seal 22 and the retaining ring 24, the overall dimensions of the buffer seal 22 and the retaining ring 24, and other factors that may affect the hoop stress and other stresses experienced by the components under different operating conditions. As an example, the radius 336 of the convex radius R can be predetermined to have a value greater than or equal to half the thickness or axial width W (332) of the retaining ring 24 and less than or equal to twice the axial width W (332). In this exemplary embodiment, annular groove 21 may have a width 320 of 8.3 mm plus 0.2 mm and minus 0.0 mm, and a depth 324 (the difference between the radius at the bottom of annular groove 21 and the inner radius of cylinder head 16 ) depending on the specific application, for example anywhere from 25 mm to 450 mm.

[0019] In some exemplary embodiments, the retaining ring 24 may be made of a harder and stronger plastic material than the material of the buffer seal 22. Examples of suitable materials for the retaining ring 24 may include polytetrafluoroethylene (PTFE), acetal (POM), nylon or other materials, composites or matrices. The buffer seal 22 may be formed of materials such as polyurethane, rubber or other elastomers.

[0020] Under non-low load or pressure conditions, there may be a gap between at least a portion of the radial inner surface 245 of the retaining ring and the outer peripheral surface of the piston rod 12. The gap can provide area or distance for some displacement of the retaining ring 24 during higher pressure applications. The gap can also absorb energy generated by hoop stresses in the retaining ring 24 and reduce the overall contact force and friction between the retaining ring 24 and the buffer seal 22. Figure 3 In the exemplary embodiment shown, the retaining ring 24 is configured to extend along the entire radial extent of the axial sealing surface 224 of the buffer seal 22, so that the retaining ring 24 provides optimal extrusion resistance to the buffer seal 22. The cooperative mating relationship between the retaining ring 24 and the buffer seal 22 also maintains an optimal stress distribution in the area of ​​the retaining ring 24 by limiting deformation of the buffer seal 22 relative to the retaining ring 24. The retaining ring 24, which is made of a stronger material relative to the buffer seal 22, is able to withstand greater forces associated with increased pressure on the buffer seal 22, which is possible compared to the case where there is no retaining ring 24 or a retaining ring 24 that does not extend along the entire radial extent of the axial sealing surface 224 of the buffer seal 22.

[0021] like Figure 1 , Figure 2 and Figure 4 As shown, the buffer seal 22 of various embodiments of the present invention can be used as a part of the piston rod seal and the wear member axially spaced apart along the inner circumferential surface of the cylinder head 16 to form a sealing assembly between the piston rod 12 and the cylinder head 16. In the cylinder barrel 14 of the hydraulic cylinder 10, a rod end cavity can be formed between the piston 13 and the cylinder head 16. Figure 1 , Figure 2 and Figure 4 As shown, the cylinder head 16 of various embodiments of the utility model extends from the piston rod 12 through the axial end face of the cylinder head 16 to the rod end cavity in the hydraulic cylinder 10 and may include in sequence: a cylindrical metal wear guide 340, a U-cup seal 360, the buffer seal assembly and additional seals and wear parts (not shown), the cylindrical metal wear guide 340 is arranged in an annular groove 341 formed around the inner circumferential surface of the cylinder head 16, the buffer seal assembly has a buffer seal 22 and a retaining ring 24 arranged in the annular groove 21, the U-cup seal 360 is arranged in the annular groove 361, additional seals and wear parts such as a cylindrical nylon wear guide arranged in an annular groove and a three-lip wiping seal including three annular lips arranged in the annular groove or arranged in multiple adjacent annular grooves.

[0022] Each of the wear guides and seals or assemblies may engage the outer circumferential surface of the piston rod 12 as the piston rod 12 moves axially within the cylinder head 16 to extend and retract relative to the hydraulic cylinder 10. In addition to providing an additional sealing interface between the piston rod 12 and the cylinder head 16, the metal wear guides and nylon wear guides may also help to keep the piston rod in a centered position within the buffer seal assembly, the U-cup seal 360, and the wiper seal. Each wear guide may include one or more annular rings disposed in one or more annular grooves formed in the inner circumferential surface of the cylinder head 16. The buffer seal assembly having the buffer seal 22 and the retaining ring 24 may be the seal closest to the rod end cavity within the cylinder barrel 14. The three-lip wiper seal may be the outermost seal. The U-cup seal 360 may be disposed between the buffer seal assembly and the wiper seal.

[0023] One function of the buffer seal assembly, such as the buffer seal axially adjacent to the U-cup seal 360 and the one closest to the rod end cavity among the plurality of seal rings, is to create a high pressure seal to prevent fluid from escaping from the rod end cavity. However, some fluid may leak through the buffer seal assembly along the outer peripheral surface of the piston rod 12.

[0024] The U-cup seal 360 can provide a second barrier to prevent fluid from leaking out of the hydraulic cylinder 10. Any fluid that leaks through the buffer seal assembly can be scraped off the outer peripheral surface of the piston rod 12 by the lip of the U-cup seal 360. The fluid can be collected in the recess formed in the U-cup seal 360. When the fluid pressure in the rod end cavity decreases to a relatively low level, the fluid pressure formed in the recess of the U-cup seal 360 can act on the buffer seal 22 to move the lip of the buffer seal 22 (at Figure 3 , a portion of the surface 227 at the distal end of the radially inner annular leg of the buffer seal having the pressure surface 221, which terminates at the radially inner annular pressure surface 220) is disengaged from the outer peripheral surface of the piston rod 12. The disengagement of the buffer seal 22 from the outer peripheral surface of the piston rod 12 allows the trapped fluid to return to the rod end chamber of the hydraulic cylinder 10.

[0025] For example, one function of a three-lip wiper seal as the outermost seal is to prevent dirt and debris from contaminating the fluid in the hydraulic cylinder 10. The wiper seal can be forcibly assembled into an annular groove formed in the inner circumferential surface of the cylinder head 16. When the three-lip wiper seal is in place in the annular groove formed in the cylinder head 16, the piston rod 12 can be inserted through the central opening in the wiper seal. The central opening of the wiper seal can be configured to have a close tolerance with the outer circumferential surface of the piston rod 12, so that each lip of the three-lip wiper seal forms a compression seal with the outer circumferential surface of the piston rod 12. In other words, the piston rod 12 is inserted into the opening in the wiper seal, causing each lip of the wiper seal to apply a force on the outer circumferential surface of the piston rod 12, thereby producing a seal. The cutout adjacent to each lip of the three-lip wiper seal provides an area into which the main body portion of each lip can be bent when the piston rod 12 passes through the wiper seal. This bending action of the main body portion of each lip of the wiper seal reduces the amount of compression of each main body portion and therefore reduces the force applied by each lip on the outer peripheral surface of the piston rod 12 without significantly reducing the contact area of ​​the lip on the outer peripheral surface of the piston rod 12. In this way, when the piston rod 12 slides in the cylinder 14, the wiper seal forms an effective seal with the outer peripheral surface of the piston rod 12 without excessively wearing the surface of the piston rod 12.

[0026] Industrial Applicability

[0027] The utility model relates to a buffer seal assembly, which includes an annular buffer seal 22 and a retaining ring 24 matched therewith, and the entire arrangement of the axially spaced annular seal and the annular wear guide can be arranged in an annular groove formed in the inner circumferential surface of the cylinder head 16 of the hydraulic cylinder 10. The arrangement of the axially spaced annular seal and the annular wear guide may include or exclude the disclosed buffer seal assembly. In the arrangement including the buffer seal assembly, the buffer seal 22 can cooperate with the retaining ring 24 and be located in the annular groove formed in the inner circumferential surface of the cylinder head 16 of the hydraulic cylinder 10. As described above, the annular buffer seal 22 may include a first axial pressure side and an opposite second axial sealing side, the first axial pressure side is formed with a plurality of continuous axial pressure surfaces 220, 221, 222 and 223 facing the pressurized rod end cavity of the hydraulic cylinder 10, and the opposite second axial sealing side is formed with an axial sealing surface 224, which faces the outside of the hydraulic cylinder 10 and is configured to contact the retaining ring 24 in a cooperative relationship in the annular groove 21. The buffer seal 22 also includes a radial outer circumferential surface 226 and a radial inner circumferential surface 227. The radial outer circumferential surface 226 is configured to contact the bottom portion or the whole of the annular groove 21 along the outer circumferential surface, and the radial inner circumferential surface 227 is configured to contact the portion or the whole of the piston rod 12 that can move axially in the cylinder head 16 along the inner circumferential surface.

[0028] The two pressure surfaces on the axial pressure side of the buffer seal 22 may be axially tapered surfaces that converge to define an annular recess 23 on the axial pressure side of the annular buffer seal 22, the recess 23 separating the radially outer annular leg and the radially inner annular leg, and the distal end of the radially inner annular leg forming a lip configured to seal against the outer circumferential surface of the piston rod 12 when the piston rod 12 is extended and retracted in the cylinder head 16. In an optional embodiment of the buffer seal 22, the pressure surface on the axial pressure side of the buffer seal 22 may form more than one annular recess along the radial extent of the buffer seal 22. The pressure from the rod end chamber of the hydraulic cylinder 10 may enter the annular recess 23 or more than one recess defined in the axial pressure side of the buffer seal 22 through the metal wear guide 340. The pressure may cause the radially outer annular leg of the buffer seal 22 to bend radially outward and press against the bottom surface of the annular groove 21, and cause the radially inner annular leg including the lip 342 of the buffer seal 22 to bend radially inward and press against the piston rod 12. The radially outer circumferential surface 226 of the buffer seal 22 may be configured with a portion adjacent to or in contact with the bottom of the annular groove 21 along its axial length, and when the pressure applied to the annular recess 23 drops below a certain threshold, a small gap is formed between the portion of the radially outer circumferential surface 226 adjacent to or in contact with the bottom of the annular groove 21 and the bottom of the annular groove 21. Similarly, in various embodiments of the annular buffer seal 22 according to the present invention, the radially inner circumferential surface 227 of the buffer seal 22 is configured with a portion in contact with the radially outer circumferential surface of the piston rod 12 along its axial length or its entire axial length. As the piston rod 12 moves axially relative to the cylinder head 16 and the hydraulic cylinder 10 to extend and retract, portions of one or both of the radially outer circumferential surface 226 and the radially inner circumferential surface 227 of the buffer seal 22 may remain spaced from the bottom of the annular groove 21 and the piston rod 12, depending on the amount of pressure applied to the annular recess 23 from the pressurized rod end chamber of the hydraulic cylinder 10. Higher pressures above a certain threshold introduced into the annular recess 23 from the rod end chamber of the hydraulic cylinder 10 may cause one or both of the radially outer annular leg having the pressure surface 222 and the radially inner annular leg having the pressure surface 221 to flex, thereby creating a tighter seal between one or more portions of the annular buffer seal 22 and the annular groove 21 and / or the piston rod 12.

[0029] like Figure 3As shown, as described above, the axial sealing surface 224 of the buffer seal 22 cooperates with the retaining ring 24, and the buffer seal 22 and the retaining ring 24 can be cooperatively received in the annular groove 21 formed in the radial inner circumferential surface of the cylinder head 16 of the hydraulic cylinder 10. Alternative embodiments of the buffer seal 22 and the retaining ring 24 that cooperate therewith can eliminate or change the above-mentioned dimensions or configurations, wherein the entire radial extent of the axial sealing side of the buffer seal 22 is substantially coplanar, curved, and formed with one or more annular steps or recesses to form a step or recess.

[0030] The entire arrangement of the buffer seal assembly and / or annular seal and wear guide disclosed above can be incorporated into the seal assembly of any hydraulic component. Therefore, the seal and the combination of the seal and wear guide of the utility model have a wide range of applications in various machines including hydraulic actuators and / or hydraulic cylinders. Some advantages of the disclosed embodiments include providing a robust piston rod sealing system with multiple contaminant barriers, having higher resistance to the potentially harmful effects of temperature, humidity and pressure in the hydraulic actuator, optimizing the side load of the hydraulic cylinder components incorporating the disclosed features, fewer machine downtimes for servicing the hydraulic cylinder, longer life of the hydraulic cylinder components, including extended piston rod life, and extended oil life of the hydraulic cylinder due to avoiding contaminants from penetrating into the hydraulic cylinder or hydraulic fluid leakage from the hydraulic cylinder.

[0031] It is obvious to those skilled in the art that various modifications and changes can be made to the individual seals, seal assemblies, and seal devices of the present invention without departing from the scope or spirit of the present invention. Other embodiments of the present invention will be obvious to those skilled in the art in view of the specification and the practice disclosed herein. This specification and examples are exemplary only, and the true scope and spirit of the present invention are indicated by the appended claims and their equivalents.

[0032] Parts List

[0033] 10 Hydraulic cylinder

[0034] 11 Closed cap end

[0035] 12 Piston rod

[0036] 13 Piston

[0037] 14 Cylinder

[0038] 16 Cylinder head

[0039] Array of 18 annular piston rod seals

[0040] 21 Annular groove

[0041] 22 Annular buffer seal

[0042] 23 recess

[0043] 24 Retaining ring

[0044] 220 Radial inner ring pressure surface

[0045] 221 Pressure Surface

[0046] 222 Pressure surface

[0047] 223 Radial outer ring pressure surface

[0048] 224 Axial sealing surface

[0049] 226 Radial outer circumferential surface

[0050] 227 Radial inner circumferential surface

[0051] 245 Radial inner surface of the retaining ring

[0052] 300 Central Axis

[0053] 320 Width of the annular groove

[0054] 324 Depth of annular groove

[0055] 332 Axial width of the retaining ring

[0056] 334 Difference between the outer diameter and the inner diameter of the retaining ring

[0057] 336 Convex radius of retaining ring

[0058] 340 Wear Guide

[0059] 341 Annular groove

[0060] 342 Lip of annular buffer seal

[0061] 360 U-cup seals

[0062] 361 Annular groove.

Claims

1. A sealing assembly for a hydraulic cylinder piston rod, characterized in that: include: an annular buffer seal having a first axial pressure side and a second axial sealing side opposite the first axial pressure side, the first axial pressure side being configured to face the rod end cavity of the hydraulic cylinder and adjacent to a first axial side surface of an annular groove defined in a cylinder head at the rod end of the hydraulic cylinder, the piston rod passing through the annular groove; as well as An annular disc-shaped retaining ring is configured to extend along the entire radial extent of the second axial sealing side of the annular buffer seal and is axially positioned between the annular buffer seal and the second axial side surface of the annular groove.

2. The sealing assembly according to claim 1, characterized in that: The first axial pressure side of the annular buffer seal includes a radially outer annular pressure surface, which is connected to a radially inner annular pressure surface via two continuous and converging conical pressure surfaces, and on the first axial pressure side of the buffer seal, the two continuous and converging conical pressure surfaces form an annular recess.

3. The sealing assembly according to claim 1, characterized in that: The retaining ring includes a chamfered outer circumferential surface at a radially outer edge of a side of the retaining ring facing away from the buffer seal.

4. The sealing assembly according to claim 1, characterized in that: The annular buffer seal also includes a radially outer circumferential surface in contact with the bottom of the annular groove and a radially inner circumferential surface in contact with the piston rod.

5. The sealing assembly according to claim 4, characterized in that: The radial outer circumferential surface of the annular buffer seal is configured with portions along its axial length that are adjacent to or in contact with the bottom of the annular groove. When the pressure applied to the first axial pressure side of the buffer seal drops below a predetermined threshold, a small gap is formed between some of the portions of the radial outer circumferential surface and the bottom of the annular groove.

6. The sealing assembly according to claim 2, characterized in that: The annular recess is defined between a radially outer annular leg of the buffer seal and a radially inner annular leg of the buffer seal.

7. The sealing assembly according to claim 6, characterized in that: Pressure applied to the annular recess causes the radially outer annular leg to bend radially outward and press against the bottom surface of the annular groove, and causes the radially inner annular leg to bend radially inward and press against the piston rod.

8. The sealing assembly according to claim 3, characterized in that: The radius of the chamfered outer circumferential surface of the retaining ring is in a range from half of an axial width of the retaining ring to twice the axial width of the retaining ring.

9. The sealing assembly according to claim 1, characterized in that: The axial width of the retaining ring is in the range of 1.70 mm to 2.00 mm.

10. A hydraulic cylinder, characterized in that: include: Cylinder barrel; a cylinder head located at the rod end of the cylinder barrel; a piston rod extending through the cylinder head at the rod end of the cylinder and configured to move axially relative to the rod end of the cylinder; a plurality of seals disposed in axially spaced annular grooves formed about an inner circumferential surface of the cylinder head at the rod end of the cylinder barrel and configured to sealingly engage the piston rod; One of the plurality of seals is a seal assembly including an annular buffer seal having a first axial pressure side and a second axial sealing side opposite the first axial pressure side, the first axial pressure side being configured to face the rod end cavity of the hydraulic cylinder and adjacent to a first axial side surface of an annular groove defined in the cylinder head through which the piston rod passes; and The sealing assembly also includes an annular disc-shaped retaining ring, which is configured to extend along the entire radial range of the second axial sealing side of the annular buffer seal and is axially positioned between the annular buffer seal and the second axial side surface of the annular groove, and the radial outer circumferential surface of the retaining ring includes a chamfered portion facing the second axial side surface of the annular groove.

11. The hydraulic cylinder according to claim 10, characterized in that: The first axial pressure side of the annular buffer seal includes a radially outer annular pressure surface, which is connected to a radially inner annular pressure surface via two continuous and converging conical pressure surfaces, and on the first axial pressure side of the buffer seal, the two continuous and converging conical pressure surfaces form an annular recess.

12. The hydraulic cylinder according to claim 10, characterized in that: The retaining ring includes a chamfered outer circumferential surface at a radially outer edge of a side of the retaining ring facing away from the buffer seal.

13. The hydraulic cylinder according to claim 10, characterized in that: The annular buffer seal also includes a radially outer circumferential surface in contact with the bottom of the annular groove and a radially inner circumferential surface in contact with the piston rod.

14. The hydraulic cylinder according to claim 13, characterized in that: The radial outer circumferential surface of the annular buffer seal is configured with portions along its axial length that are adjacent to or in contact with the bottom of the annular groove. When the pressure applied to the first axial pressure side of the buffer seal drops below a predetermined threshold, a small gap is formed between some of the portions of the radial outer circumferential surface and the bottom of the annular groove.

15. The hydraulic cylinder according to claim 11, characterized in that: The annular recess is defined between a radially outer annular leg of the buffer seal and a radially inner annular leg of the buffer seal.

16. The hydraulic cylinder according to claim 15, characterized in that Pressure applied to the annular recess causes the radially outer annular leg to bend radially outward and press against the bottom surface of the annular groove, and causes the radially inner annular leg to bend radially inward and press against the piston rod.

17. The hydraulic cylinder according to claim 12, characterized in that: The radius of the chamfered outer circumferential surface of the retaining ring is in a range from half of an axial width of the retaining ring to twice the axial width of the retaining ring.

18. The hydraulic cylinder according to claim 10, characterized in that: The axial width of the retaining ring is in the range of 1.70 mm to 2.00 mm.

19. An annular disc-shaped retaining ring, characterized in that: The retaining ring is configured to press against the entire radial extent of the axial sealing side of the annular buffer seal when the retaining ring and the annular buffer seal are installed as a sealing assembly in an annular groove formed in the inner circumferential surface of the cylinder head at the piston rod end of the hydraulic cylinder for sealing engagement with the piston rod passing through the cylinder head, and The radially outer circumferential surface of the retaining ring includes a chamfered portion facing an axial side surface of the annular groove.

20. The retaining ring according to claim 19, characterized in that When the axial width of the annular groove is in the range of 8.3 mm to 8.5 mm, the axial width of the retaining ring is configured to be in the range of 1.70 mm to 2.00 mm.

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