Patent Application
20170067561
This patent disclosure relates generally to a face seal and, more particularly, to a face seal for use in high pressure applications.
A face seal includes sealing surfaces that extend in a plane that is normal to the axis of the seal. Face seals are typically used in a static application to prevent leakage in the radial direction with respect to the axis of the seal. Face seals are typically located in a groove or cavity, such as in a flange, of one of the members being sealed together by the face seal.
Normally, the sealing surfaces of the face seal are in abutting relationship to each other and are held in fixed relationship to each other over a range of operating conditions. However, in some applications—such as those experiencing cyclic pressure changes, for example—a gap can be periodically defined between the sealing surfaces. When such a condition exists, the seal member may deform sufficiently such that a portion of the seal member is extruded into the gap. When the pressure condition changes and the sealing surfaces return to their abutting relationship, the portion of the seal member extruded into the gap is pinched between the sealing surfaces, leading to the deterioration and/or failure of the seal.
U.S. Pat. No. 7,828,301 is entitled, “Self-Energized Backup Ring for Annular Seals,” and is directed to an apparatus including an annular seal (e.g., an o-ring) and a backup ring to provide support to the annular seal. A gland is provided to accommodate the backup ring and the annular seal. The gland has a contact surface which is adapted to contact a corresponding contact surface of the backup ring upon inserting the backup ring into the gland. The diameters of the contact surfaces of the backup ring and gland are sized such that the contact surface of the backup ring radially interferes with the contact surface of the gland, thereby urging the backup ring out of the gland. A retention mechanism, such as interlocking grooves, protrusions, ridges, notches, slots, or the like may be provided in the backup ring and gland respectively to prevent the backup ring from completely exiting the gland.
There is a continued need in the art to provide additional solutions to enhance the performance of face seals. For example, there is a continued need for a face seal which can accommodate relative axial motion of sealing surfaces without undergoing excessive extrusion conditions.
It will be appreciated that this background description has been created by the inventors to aid the reader, and is not to be taken as an indication that any of the indicated problems were themselves appreciated in the art. While the described principles can, in some respects and embodiments, alleviate the problems inherent in other systems, it will be appreciated that the scope of the protected innovation is defined by the attached claims, and not by the ability of any disclosed feature to solve any specific problem noted herein.
In an embodiment, the present disclosure describes a face seal that includes a first member, a second member, a seal member, and a backup ring. The first member and the second member are mounted together.
The first member extends along a longitudinal axis and includes a first sealing surface. The first sealing surface extends radially relative to the longitudinal axis. The first member defines an interior cavity. The second member includes a second sealing surface which extends radially relative to the longitudinal axis. The second sealing surface is adjacent to the first sealing surface. At least one of the first sealing surface and the second sealing surface defines an annular groove.
The seal member is annular and has a seal diameter. The seal member is disposed within the annular groove. The seal member is in sealing contact with the first sealing surface and the second sealing surface. The backup ring is annular and has a ring diameter which is larger than the seal diameter. The backup ring is disposed within the annular groove such that the seal member is radially inward of the backup ring.
The second sealing surface is movable relative to the first sealing surface in response to an axial force applied along the longitudinal axis by an interior cavity pressure, thereby defining an axial gap between the first sealing surface and the second sealing surface. The axial gap has an outer gap opening adjacent the annular groove. The backup ring is interposed between the seal member and the outer gap opening of the axial gap such that the backup ring occludes the outer gap opening.
In yet another embodiment, a backup ring for a face seal includes an inner cylindrical sidewall and an end. The inner cylindrical sidewall is cylindrical. The inner cylindrical sidewall extends along, and circumscribes a longitudinal axis. The end adjoins the inner cylindrical sidewall. The end has a tapered end surface which is annular. The tapered end surface defines an oblique angle with respect to a radial plane which is perpendicular to the longitudinal axis.
In still another embodiment, a backup ring for a face seal includes a sidewall, an end, and a tapered surface. The sidewall is cylindrical and includes an end edge and a taper edge. The sidewall extends between the end edge and the taper edge along a longitudinal axis, and the sidewall circumscribes the longitudinal axis. The end is annular and includes a sidewall edge and a radial edge in spaced radial relationship to the sidewall edge. The sidewall edge of the end adjoins the end edge of the sidewall. The tapered surface extends from the radial edge of the end radially and longitudinally toward the taper edge of the sidewall.
Further and alternative aspects and features of the disclosed principles will be appreciated from the following detailed description and the accompanying drawings. As will be appreciated, the principles related to face seals and backup rings disclosed herein are capable of being carried out in other and different embodiments, and capable of being modified in various respects. Accordingly, it is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and do not restrict the scope of the appended claims.
It should be understood that the drawings are not necessarily to scale and that the disclosed embodiments are sometimes illustrated diagrammatically and in partial views. In certain instances, details which are not necessary for an understanding of this disclosure or which render other details difficult to perceive may have been omitted. It should be understood, of course, that this disclosure is not limited to the particular embodiments illustrated herein.
The present disclosure provides embodiments of a face seal with a seal member and a backup ring. In embodiments, a face seal constructed in accordance with principles of the present disclosure can be incorporated into any suitable machine. Examples of such machines include mobile or fixed machines used for construction, farming, mining, forestry, transportation, and other similar industries. In some embodiments, the machine can be an excavator, tractor, wheel loader, backhoe, crane, compactor, dozer, wheel tractor-scraper, material-handling machine, or any other suitable machine which includes a face seal.
Embodiments of a face seal constructed according to principles of the present disclosure can have a seal member and a backup ring made from an elastomeric material that is sufficiently elastic to accommodate relative axial movement between sealing surfaces (such as, an annular groove in an end of a cylinder and a mating cover, for example) while occluding any axial gap defined therebetween. In embodiments, the tapered backup ring is made from a material that has a modulus of elasticity that is higher than the material from which the seal member is made. In embodiments, the backup ring is tapered such that the axial force necessary to bring the sealing surfaces into abutting relationship during assembly of the parts is reduced relative to a non-tapered configuration.
Turning now to the FIGURES, there is shown in
In embodiments, the pressure in the cylinder 55 of the hydraulic actuator 25 is very high in order to move the piston 70 to the extended position, particularly when the piston 70 is used to produce a working force in an implement, for example. As such, the pressure in the cylinder 55 changes cyclically as the piston 70 is reciprocally moved over its range of travel between the retracted position and the extended position.
Referring to
The first and second members 80, 82 can be made from any suitable material, such as metal, for example. In embodiments, the first member 80 extends along a longitudinal axis LA and includes a first sealing surface 92. The first sealing surface 92 extends radially relative to the longitudinal axis LA. The first member 80 defines an interior cavity 94.
In the illustrated embodiment, the first member 80 is in the form of the tube and has an end 97 which is annular. The end 97 of the tube 80 is configured to facilitate the mounting of the second member 82 thereto. The first sealing surface 92 is disposed at the end 97 and extends along a radial plane RP that is perpendicular to the longitudinal axis LA (see
The interior cavity 94 can be placed in hydraulic communication with a supply of hydraulic fluid configured to selectively operate the hydraulic actuator 25. In embodiments, the tube 80 includes an opposing end 98 which can be closed by any suitable arrangement, such as a suitable plug or cover mounted thereto by a plurality of threaded fasteners, for example.
Referring to
At least one of the first sealing surface 92 and the second sealing surface 102 defines an annular groove 105. In the illustrated embodiment, the first sealing surface 92 of the first member 80 defines the annular groove 105. The annular groove 105 has a groove depth Δgroove, measured along the longitudinal axis LA between a seal face 107 and a groove base 108 of the first sealing surface 92.
Referring to
Referring to
In the illustrated embodiment, when the seal member 85 is in an unloaded or uncompressed condition, as shown in
The backup ring 90 is annular. The backup ring 90 has a ring diameter Øring which is larger than the seal diameter Øseal. The backup ring 90 is disposed within the annular groove 105 such that the seal member 85 is radially inward of the backup ring 90. The backup ring 90 is coaxial with the longitudinal axis LA of the tube 80. In the illustrated embodiment, when in the unloaded—or uncompressed—condition, the backup ring 90 maintains the cross-sectional shape shown in
In embodiments, the seal member 85 is made from a first material with a first modulus of elasticity, and the backup ring 90 is made from a second material with a second modulus of elasticity which are respectively different from the first material and the second modulus of elasticity. In embodiments, the modulus of elasticity of the material from which the backup ring 90 is made is higher than the modulus of elasticity of the material from which the seal member 85 is made. For example, in embodiments, the seal member 85 is made from a suitable elastomeric material, such as a fluoroelastomer, and the backup ring 90 is made from a suitable elastomeric material, such as a thermoplastic polyester elastomer. In embodiments, the backup ring 90 is made from a material which is harder than the material from which the seal member 85 is made.
Referring to
In embodiments, the backup ring 90 includes at least one tapered surface 125 configured to reduce the assembly force for bringing the second sealing surface 102 into abutting contact with the first sealing surface 92 relative to a backup ring configuration with a rectangular cross-sectional shape 130 circumscribing a cross-sectional shape 132 of the backup ring 90 with the tapered surface 125 (see
Referring to
The axial gap Δgap has an outer gap opening 140 adjacent the outer groove sidewall 122 of the annular groove 105. The backup ring 90 is interposed between the seal member 85 and the outer gap opening 140 of the axial gap Δgap such that the backup ring 90 occludes the outer gap opening 140. In embodiments, the backup ring 90 prevents the seal member 85 from extruding into the seal gap Δgap. The pressure within the interior cavity 94 urges the seal member 85 radially outwardly against the backup ring 90. The backup ring 90 is compressed radially against the outer groove sidewall 122. The backup ring 90 maintains contacting engagement with both the first sealing surface 92 (over the groove base 108 and the outer groove sidewall 122) and the second sealing surface 102 to occlude the outer gap opening 140. When the pressure in the interior cavity 94 is reduced, the second sealing surface 102 can return to abutting relationship with the first sealing surface 92, as shown in
Referring to
Referring to
The inner cylindrical sidewall 150 has an inner height Hinner, measured along the longitudinal axis LA, and the outer cylindrical sidewall 152 has an outer height Houter, measured along the longitudinal axis LA, when in an uncompressed condition. The inner height Hinner of the inner cylindrical sidewall 150 is greater than the outer height Houter of the outer cylindrical sidewall 152.
Referring to
Referring back to
The first end 154 adjoins the inner cylindrical sidewall 150. The first end 154 includes a first base end surface 172 and the first tapered end surface 170. The first base end surface 172 is radially inward of the first tapered end surface 170 and is in adjoining relationship with the inner cylindrical sidewall 150. The first base end surface 172 extends along the radial plane RP and is substantially perpendicular to the longitudinal axis LA when the backup ring 90 is in an uncompressed condition.
The first chamfer surface 158 extends between the first tapered end surface 170 of the first end 154 and the outer cylindrical sidewall 152. The first tapered end surface 170 of the first end 154 is disposed radially within the first chamfer surface 158. The first chamfer surface 158 defines a second taper angle θ2 with respect to the radial plane RP when in an uncompressed condition. In embodiments, the second taper angle θ2 is oblique and is different from the first taper angle θ1.
In embodiments, the first and second taper angles θ1, θ2 can be any suitable oblique angle. In the illustrated embodiment, the second taper angle θ2 is greater than the first taper angle θ1. In embodiments, the second taper angle θ2 is at least twice as large as the first taper angle θ1. In one embodiment, the first taper angle θ1 is about fifteen degrees, and the second taper angle θ2 is about forty-five degrees.
The second end 155 and the second chamfer surface 159 are substantially the same as the first end 154 and the first chamfer surface 158, respectively, but mirror images thereof. The second end 155 includes a second tapered end surface 180 and a second base end surface 182. The second tapered end surface 180 is annular. The second base end surface 182 is radially inward of the second tapered end surface 180 and is in adjoining relationship with the inner cylindrical sidewall 150. The first tapered end surface 170 and the second tapered end surface 180 converge toward each other, moving radially outward from the inner cylindrical sidewall 150. The second end 155 and the second chamfer surface 159 are similar in other respects to the first end 154 and the first chamfer surface 158, respectively. In other embodiments, the second end 155 and/or the second chamfer surface 159 can have a configuration that is different from the first end 154 and the first chamfer surface 158, respectively.
Referring to
The backup ring 290 includes a sidewall 352, an end 354, and a tapered surface 325. The sidewall 352 is cylindrical and includes an end edge 385 and a taper edge 386. The sidewall 352 extends between the end edge 385 and the taper edge 386 along a longitudinal axis LA, and the sidewall 352 circumscribes the longitudinal axis LA. The end 354 is annular and includes a sidewall edge 388 and a radial edge 389 in spaced radial relationship to the sidewall edge 388. The sidewall edge 388 of the end 354 adjoins the end edge 385 of the sidewall 352. The tapered surface 325 extends from the radial edge 389 of the end 354 radially and longitudinally toward the taper edge 386 of the sidewall 352.
In the illustrated embodiment, the sidewall 352 comprises an outer cylindrical sidewall. The end 354 extends between the sidewall edge 388 and the radial edge 389 along the radial plane RP, which is perpendicular to the longitudinal axis LA.
In the illustrated embodiment, the backup ring 290 also includes a tip end 392. The tip end 392 is in spaced relationship to the end 354 along the longitudinal axis LA. The tip end 392 extends radially between the tapered surface 325 and the taper edge 386 of the sidewall 352. The tip end 392 extends along the radial plane RP, which is perpendicular to the longitudinal axis LA.
Referring to
The outer cylindrical sidewall 352 has a backup ring height Hring, measured along the longitudinal axis LA, when in an uncompressed condition. In the illustrated embodiment, the backup ring height Hring of the backup ring 290 is less than the groove depth of the annular groove 105. The backup ring 290 of
The industrial applicability of the embodiments of a face seal described herein will be readily appreciated from the foregoing discussion. At least one embodiment of a face seal constructed according to principles of the present disclosure can be used in a machine to help maintain a seal under cyclic pressure conditions. Embodiments of a face seal according to principles of the present disclosure may find potential application in any suitable machine, such as in use with a hydraulic hammer, demolition shears, etc.
Embodiments of a face seal constructed according to principles of the present disclosure can have a seal member and a backup ring made from an elastomeric material that is sufficiently elastic to accommodate relative axial movement between sealing surfaces while sufficiently stiff to occlude any axial gap defined therebetween and to prevent the seal member from extruding into the axial gap. In embodiments, the backup ring is made from a material that has a modulus of elasticity that is higher than the material from which the seal member is made. In embodiments, the backup ring is tapered such that the axial force necessary to bring the sealing surfaces into abutting relationship during assembly of the parts is reduced relative to a non-tapered configuration.
Embodiments of a face seal constructed according to principles of the present disclosure can be used between sealing surfaces of components subjected to cyclic pressure changes, such as those found in a cylinder of a hydraulic actuator, for example. Increased fluid pressure experienced during a power stroke of the piston can cause the sealing surfaces to move axially apart from each other, defining a gap therebetween. The gap can open and close as the pressure cycles. A face seal constructed according to principles of the present disclosure can be configured to follow the joint motion while maintaining the seal member's sealing contact between the sealing surfaces without undergoing excessive extrusion into the gap. Embodiments of a face seal constructed according to principles of the present disclosure can be used can be used in other applications as will be appreciated by one skilled in the art.
In embodiments, the tapered backup ring is constructed such that the axial assembly force for bringing the sealing surfaces together during the assembly of the components is reduced relative to a non-tapered shape. In embodiments, the tapered backup ring can have different shapes, such as, a triangle or a polygon having at least four sides, for example.
It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for the features of interest, but not to exclude such from the scope of the disclosure entirely unless otherwise specifically indicated.
Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.
This patent application claims the benefit of U.S. Provisional Patent Application No. 62/214,769, filed Sep. 4, 2015, which is incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62214769 | Sep 2015 | US |
