WO2005033559A1

WO2005033559A1 - Retainer gasket construction

Info

Publication number: WO2005033559A1
Application number: PCT/US2004/028679
Authority: WO
Inventors: Jay M Jones; Douglas C. Schenk
Original assignee: Parker-Hannifin Corporation
Priority date: 2003-10-01
Filing date: 2004-09-03
Publication date: 2005-04-14

Abstract

Sealing gasket construction for providing a fluid seal intermediate a pair of opposed, mating parts or structures. The gasket includes a metal retainer and a resilient seal element received in a groove portion formed between sections of the retainer.

Description

RETAINER GASKET CONSTRUCTION

BACKGROUND OF THE INVENTION The present invention relates broadly to a sealing construction for providing a fluid seal intermediate a pair of opposed, mating parts or structures, and more particularly to such a construction including a seal member which is received within a gap formed between a first and a second section of a retainer. In basic construction, gaskets of the type herein involved are formed of one or more resilient sealing elements which are supported by sheet metal plate or other retainer which may be machined, stamped, molded or otherwise formed to conform to the geometry of the mating surfaces to be sealed. Particularly, the seal members may be molded-in-place or otherwise mounted in grooves formed into one or both sides of the retainer. Representative such gaskets are shown, for example, in U.S. Patent Nos. 3,195,906; 3,215,442; 3,259,404; 3,578,346; 3,635,480; 3,720,420; 3,746,348; 4,026,565, 4,625,978, 5,890,719; 6,460,859; and 6,553,664, in U.S. Pat. Appln. Pub. No. 2003/0025328A1; 2002/0140182A1; 2002/0135137A1; and US2002/0030326A1, and in co-pending U.S. Provisional Pat. Appln. No. 60/497,777, filed August 26, 2003, and are marketed commercially by the Composite Sealing Systems Division of Parker-Hannifin Corporation, San Diego, CA, under the tradenames "Gask-O-Seal" and "Integral Seal." Retainer gaskets of the type herein involved are employed in a variety of sealing applications, such as in commercial, industrial, or military equipment, vehicles, or aircraft for compression between the opposing or faying surfaces of a pair of mating parts or structures to provide a fluid-tight interface sealing thereof, h service, the gasket is clamped between the mating surfaces to effect the compression and deformation of the seal member and to develop a fluid-tight interface with each of those surfaces. The compressive force may be developed using a circumferentially spaced-apart arrangement of bolts or other fastening members, or by a threaded engagement of the mating parts. Heretofore, the retainer grooves typically have been formed by machining. As a relatively labor-intensive and slow process, machining thus constitutes a significant expense in the overall cost of the gasket. It is believed, therefore, that lower cost alternatives would be well-received by industry, and particularly for automotive and other high volume applications.

BROAD STATEMENT OF THE INVENTION The present invention is directed to a retainer gasket construction particularly adapted for high volume applications and/or those having complex sealing geometries. The gasket includes a retainer which may be formed of plastic or, more typically, metal, and one or more integral sealing elements which are received within gaps formed between sections of the retainer. The sections are connected by one or more relatively short bridge portions which span the gap, and which form a groove with the sections. The sealing elements, which may be molded-in-place within the gaps, extend though the grooves formed by the bridge portions. Such construction advantageously may be fabricated, such as by stamping, machining, or otherwise forming the retainer, more easily than conventional constructions utilizing standard grooves machined into the retainer surfaces. The present invention, accordingly, comprises the article possessing the construction, combination of elements, and arrangement of parts and steps which are exemplified in the detailed disclosure to follow. Advantages of the present invention include a gasket construction which may be adapted for use with various sealing configurations, and particularly complex arrangements. Further advantages include a gasket construction which is economical to manufacture in high volumes. These and other advantages will be readily apparent to those skilled in the art based upon the disclosure contained herein. BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings wherein: Fig. 1 is a plan view of a representative embodiment of a retainer construction according to the present invention; Fig. 2 is an enlarged, fragmentary cross-sectional view of the retainer of Fig. 1 taken through line 2-2 of Fig. 1; Fig. 3 is an enlarged, fragmentary cross-sectional view of the retainer of Fig. 1 taken through line 3-3 of Fig. 1 ; Fig. 4 is an enlarged view of a detail of retainer of Fig. 1; Fig. 5 is a plan view of a representative embodiment of a gasket construction according to the present invention which incorporates the retainer of Fig. 1; Fig. 6 is an enlarged, fragmentary cross-sectional view of the gasket of Fig. 5 taken through line 6-6 of Fig. 5; and Fig. 7 is an enlarged fragmentary cross-sectional view of the gasket of Fig. 5 taken through line 7-7 of Fig. 5. The drawings will be described further in connection with the following Detailed Description of the Invention. DETAILED DESCRIPTION OF THE INVENTION Certain terminology may be employed in the following description for convenience rather than for any limiting purpose. For example, the terms "forward" and "rearward," "front" and "rear," "right" and "left," "upper" and "lower," "top" and "bottom," and "right" and "left" designate directions in the drawings to which reference is made, with the terms "inward," "inner," "interior," "inside," or "inboard" and "outward," "outer," "exterior," "outside," or "outboard" referring, respectively, to directions toward and away from the center of the referenced element, the terms "radial" or "vertical" and "axial" or "horizontal" referring, respectively, to directions, axes, or planes perpendicular and parallel to the longitudinal central axis of the referenced element. Terminology of similar import other than the words specifically mentioned above likewise is to be considered as being used for purposes of convenience rather than in any limiting sense. In the figures, elements having an alphanumeric designation may be referenced herein collectively or in the alternative, as will be apparent from context, by the numeric portion of the designation only. Further, the constituent parts of various elements in the figures may be designated with separate reference numerals which shall be understood to refer to that constituent part of the element and not the element as a whole. General references, along with references to spaces, surfaces, dimensions, and extents, may be designated with arrows or underscores. For the illustrative purposes of the discourse to follow, the precepts of the retainer gasket construction of the present invention are described in connection with the configuration thereof for use as an valve cover, intake manifold, head gasket, or other multi-port seal within an engine for a motor vehicle, i view of the discourse to follow, however, it will be appreciated that aspects of the present invention may find utility in other fluid sealing applications requiring a flexible gasket of the type herein involved. Use within those such other applications therefore should be considered to be expressly within the scope of the present invention. Referring then to the figures wherein corresponding reference characters are used to designate corresponding elements throughout the several views with equivalent elements being referenced with prime or sequential alphanumeric designations, shown generally at 12 in the plan view of Fig. 1, with the reverse side in the illustrated embodiment being understood to be substantially the same as the side shown, is a representative embodiment according to the present invention of a generally planar, retainer for use in combination with one or more elastomeric seal elements which may be mounted on one or, typically, both sides (see Fig. 2) of the retainer 12 in a retainer gasket construction. Retainer 12 may be configured as shown for interposition between a pair of interfacing surfaces, such as a cylinder head and engine block within an internal combustion engine, as having an outer margin, 14, corresponding to the outer margins of those surfaces. Such outer margin 14 may extend in the radial directions defined by the orthogonal horizontal axes referenced at 16a-b, and, as shown for illustrative purposes, may have a generally irregular shape, but which shape alternatively may be circular, elliptical, polygonal, or otherwise rectilinear depending upon the intended application. The outer margin 14 defines the radial extents of opposing upper, 18a, and lower, 18b (see Fig. 2), radial surfaces. Radial surfaces 18 each may be generally planar or, alternatively, may have one or more degrees of curvature to match the curvature of the corresponding interfacing surfaces to be sealed. Retainer gaskets of type herein involved are conventionally provided as having one or more openings formed through the radial surfaces thereof, such as for a registration with cylinder or valve bores, bolt holes, coolant or lubrication ports, and other throughbores, passageways, and chambers. In this regard, retainer 12 includes one or more openings, one of which is referenced at 20, formed through the surfaces 18. Each of such openings 20 may be configured for registration with a corresponding bore, passageway, or chamber of the engine, h this regard, it will be appreciated that the arrangement of the openings 20 shown in Fig. 1 to be formed through the retainer member 12 may correspond in number and arrangement to those formed within the interfacing surfaces of the engine components between which the gasket incorporating the retainer 12 is to be interposed. Retainer 12 further has a thickness dimension, referenced at t in the cross- sectional view of Fig. 2, defined intermediate the radial surfaces 18, and through which the which openings 20 extend. Such thickness dimension t itself extends in an axial direction along a vertical axis, referenced at 22 in Fig. 2, which axis and direction are generally normal to the radial direction referenced by the axes 16. Depending upon its material of construction and the intended application, the thickness dimension t may be between about Vi6-1 inch (0.15-2.5 cm), making the retainer 12 generally rigid. Suitable metal materials for the construction of retainer 12 include plastics and, particularly, metals such as aluminum, steel, stainless steel, copper, brass, titanium, nickel, and alloys thereof, with aluminum being preferred for many applications. The metal may be anodized, plated, or otherwise treated for increased corrosion resistance. As is shown in Fig. 1 and in the cross-sectional view of Figs. 2, retainer 12 may be seen to be divided into at least a first section, 22, and a second section, 23, which are separated by a gap, 24. As shown best in the cross-sectional view of Fig. 2, each of the sections 22 and 23 has opposing radial surfaces, 26a-b and 27a-b, respectively, which form a portion of the corresponding retainer radial surface 18a-b. Such surfaces 26 and 27, which may be generally coplanar as shown or, alternatively, non-coplanar, each extends to a corresponding axial surface, 28 and 29, defined, respectively, between the surfaces 26a-b and 27a-b. Axial surfaces 28 and 29, which may be generally orthogonal to the radial surface 26 and 27, may be generally parallel to each other as shown. Alternatively, the surfaces may be angled relative to the corresponding radial surface 26 or 27, and may be non-parallel to each other. In the arrangement shown in Fig. 1, the surfaces 26 and 27 also extend, respectively, to define an outer perimeter, 30, corresponding to the outer margin 14, and inner perimeter, 32, which, in turn, define the retainer 12 as having a generally closed geometry which may have a generally irregular shape, but which shape alternatively may be circular, elliptical, polygonal, or otherwise polygonal depending upon the intended application. Such shape also instead may be open rather than closed, and in that regard may be linear, rectilinear, or curvilinear. With continuing reference to Figs. 1 and 2, axial surface 29 is disposed opposite surface 28 along at least a portion of the length thereof to define a lengthwise extent, referenced at "L" in Fig. 1, of the gap 24, and is spaced-apart therefrom to define a widthwise extent, referenced at "w," of the gap 24. Gap 24, as disposed intermediate the retainer inner and outer perimeter 30 and 32, may generally track the shape of one or both thereof in extending lengthwise generally about the geometry thereof, and otherwise itself may have a generally closed or, alternatively, open geometry relative to the retainer surfaces 26 and 27. For connecting the sections 22 and 23, one or more bridge portions, one of which is referenced at 40, are formed within the retainer 12 as disposed intermediate the lengthwise extent L of the gap 24. Each of the bridge portions 40, which may be relatively narrow or short, may span the widthwise extent w of the gap 24 in having, as seen best in the cross-sectional view of Fig. 3, opposing radial surfaces, 42a-b, disposed axially intermediate the retainer section radial surfaces 22 and 23. In this regard, each of the bridge portions 40 may define with the retainer section axial surfaces 28 and 29 an axially-registered, generally U-shaped, first and a second groove portion, 44a-b, respectively, within the gap 24. That is, with the bridge surfaces 42a-b forming the bottom walls of the groove portions 44, and with the axial surfaces 28 and 29 forming the side walls thereof, groove portions 44a-b are thereby so defined within the gap 24. As is commonly referenced at "d" in Fig. 3, each grooves may have, relative to the corresponding radial surface 26 and 27, an axial depth which, for many applications, may be between about V8-V3 of the axial thickness, referenced at "t," of the retainer 12. Looking momentarily to Fig. 4, wherein the bridge portion 40 is shown in enhanced detail, it may be seen that the edges, referenced at 50a-b thereof may be generally concave or otherwise actuate, but as may depended specifically on the fabrication method by which the bridge portion 40, and/or the retainer 12 itself, may be formed. That is, for example, with retainer 12 being machined, stamped, molded, or otherwise formed of a sheet or other blank of a metal material, the bridge portions 40 may be first formed, as depicted in phantom at 40', as short sections of material within the gap 24 which itself may be machined or otherwise formed into the blank so as to define the sections 22 and 23. Thereupon, the sections may be cold-worked, such as by coining or punching in the manner described in co-pending Provisional Pat. Appln. No. Provisional Pat. Appln. No. 60/497,777, filed August 26, 2003, to form the U-shaped groove portions 44. In the commercial manufacture of the retainer 12, such retainer may be fabricated in a multi-station, progressive die operation or, alternatively, using separate dies in a transfer press operation. In such operation, the retainer 12, as may be provided as a piece of generally flat metal plate or sheet stock which may be machined or otherwise preformed as required, and which in various die stations or dies, may be stamped, bent, and/or coined, as well as machined or further machined, to form the final configuration of the retainer 12. Additional features and structures, such as pins, holes, openings, and the like also may be formed within the retainer 12 as the particular application may require. For example, a third retainer section, 46, may be provided as disposed between the first and second sections 22 and 23 so as to form a second opening, 47, which may be surrounded, in part, by a second gap, 48, contiguous with the first gap 24, which may be defined between the third section 46 and the first and second sections 22 and 23. As shown at 49, a portion of the first gap 24 may itself be formed between the first section 22 and the third section 46 in so forming a closed geometry surrounding the opening 20. Turning now to Fig. 5, retainer 12 reappears as incorporated within a metal and elastomer gasket construction, 50, according to the present invention. In this regard, with retainer 12 being configured as described in connection with Figs. 1-6, one or more seal elements, one of which are referenced at 52, may be molded, bonded, or otherwise attached thereto as disposed within the gap 24 as a continuous or discontinuous ring, or other length of an elastomeric material to complete the construction of the gasket 50. In this regard, seal element 52 may be seen to extend along at least a portion, and typically substantially the entirety, of the lengthwise extent L of the gap 24, as well as within the gap 48. In the arrangement shown in Fig. 5, seal element 52 thus is provided to extend lengthwise generally about the closed geometry of the retainer 12 as disposed within the gap 24 intermediate the retain inner and outer perimeter 30 and 32. In the illustrated configuration of Fig. 5, seal element 52, as disposed within a corresponding gap 24, has a first side, 54, attached to the first axial surface 28, and a second side, 56, attached to the second axial surface 29. As may be seen best in the cross-sectional views of Figs. 6-7, seal element 52 further has, relative to the retainer radial surfaces 26 and 27, a radial first sealing surface, 58a, and a radial second sealing surface, 58b, which is disposed opposite the first sealing surface 58a. As is shown, each of the surfaces 58, which may be disposed in axial registration, may be configured as a generally hemispherical or other bead or lobe. In accordance with the precepts of the present invention, seal element 52, moreover, as may be seen in Fig. 7, is provided to extend through the first and second grooved portion 44a-b so as to be received therein. That is, the seal element 52 within the groove portion 44a-b further may have a first bottom wall, 59a, which may be attached or otherwise supported on the groove surface 42a, and a second bottom wall, 59, which similarly may be supported on the opposing groove surface 42b. Each of sealing surfaces 58 may be contactible by a confronting one of the interface surfaces (not shown) between which the gasket 50 may be interposed for the axial sealing compression of the seal element 52 within the intended application. In this regard, depending upon the location of such interface surface relative to the gasket 50, each of the sealing surfaces 58 may be radially spaced-apart from a pair of corresponding sidewalls, 60a and 62a, and 60b and 62b, so as to define an annular gap, commonly referenced at 64, therebetween. The bead of the radial sealing surface, may be of any radial size, but typically will have a width, referenced at "r" in Figs. 6-7, which may be between about 25-75% of the total widthwise extent w of the gap 24. Within the gap 24, each of the sealing surfaces 58 thereby present oppositely disposed, generally hemispherical bearing surfaces which in the illustrated embodiment define radial seals on the sides defined by the surface 26 and 27 of the gasket 50. As may be seen in Fig. 5 for surface 26, such sealing surfaces extend to form a generally closed geometry along the generally closed geometry the openings 20 and 47 for coaxial registration with the margins of the interface surfaces which may surround, for example, a fluid flow passageway or chamber. It will be appreciated, however, that different and/or independent geometries of seal element 52, as well as different numbers thereof, may be envisioned depending upon the configuration of the corresponding passageway or chamber, and/or of the interfacing surfaces within the intended application. For the axial compression of the seal element 52 by the interface surfaces effecting a fluid-tight seal therewith, the sealing surfaces 58 thereof each may be provided, again as depending upon the geometry of the interface surfaces, to extend axially beyond the corresponding radial surface 26 and 27 of retainer 12 for abutting contact with a corresponding one of the interface surfaces. That is, sealing surfaces 52 may be provided, as is shown in Figs. 6-7, to protrude, as is referenced at "s" in Figs. 6-7, between about 1-100 mils (0.025-2.5 mm) beyond the corresponding radial surface 26 or 27, with the gap portions 64 being provided to accommodate the deformation of the bead portions such that the surfaces thereof each may lie coplanarly with a corresponding one of the retainer surfaces 26 or 27 when the seal element 52 is energized between the interface surfaces. The bead of the element 52 may be single as shown or, alternatively, double or more to provided redundant sealing surfaces for each of the interface surfaces. With retainer 12 being provided as has been described, seal element 52 may be adhesively bonded, interference fit or, preferably, molded, or otherwise formed in gap 24 as a continuous or discontinuous, i.e., segmented, ring or length of an elastomeric material. For the attachment of seal element 24 within gap 24 and the grooves 44 thereof, the gap and groove surfaces 28, 29, and 42, may be primed with a siloxane, silane, or other bonding agent. The primed retainer 12 then may be placed into a heated molded cavity for the injection, compression, or transfer molding of an uncured rubber or other elastomeric compound forming the integral seal elements. Each of the one or more seal elements 52 thereby may be fom ed and cured-in-place as vulcanized directly onto retainer 12. Alternatively, the elastomeric elements may be molded in a separate operation and otherwise bonded using an adhesive or interference fit into a gap 24. The seal elements 52 also may be mechanically locked onto the retainer 12, such as by virtue of the elastomeric material being injected or otherwise being flowed in encapsulating the bridge portions 40 in the manner shown in Fig. 7. Similarly, and as is shown at 70 in Fig. 5, material may be injected or otherwise flowed through holes, one of which is referenced at 72 in Fig. 1, which may be formed axially through the retainer 12. Seal element 52 may be formed of a synthetic rubber which specifically may be selected for high temperature performance or otherwise for compatibility with the fluid being handled. Suitable materials include natural rubbers such as Hevea, as well as thermoplastic, i.e., melt-processible, or thermosetting, i.e., vulcanizable, synthetic rubbers such as fluoropolymers, chlorosulfonate, polybutadiene, polybutadiene, buna-N, butyl, neoprene, nitrile, polyisoprene, silicone, fluorosilicone, copolymer rubbers such as ethylene-propylene (EPR), ethylene-propylene-diene monomer (EPDM), nitrile-butadiene (NBR) and styrene-butadiene (SBR), or blends such as ethylene or propylene-EPDM, EPR, or NBR. The term "synthetic rubbers" also should be understood to encompass materials which alternatively may be classified broadly as thermoplastic or thermosetting elastomers such as polyurethanes, silicones, fluorosilicones, styrene-isoprene-styrene (SIS), and styrene-butadiene-styrene (SBS), as well as other polymers which exhibit rubber- like properties such as plasticized nylons, polyesters, ethylene vinyl acetates, and polyvinyl chlorides. As used herein, the term "elastomeric" is ascribed its conventional meaning of exhibiting rubber-like properties of compliancy, resiliency or compression deflection, low compression set, flexibility, and an ability to recover after deformation, i.e., stress relaxation. Advantageously, seal element 52 exhibits a reduced yield stress as compared to retainer 12 and, accordingly, is deformable for conforming to irregularities existing between the interface surfaces within the intended application. Further in this regard, as given compressive load is applied to the seal element 52, an increased bearing stress is provided thereon by virtue of the reduced surface area contact of the bearing surfaces of the bead portions thereof on the interface surfaces. This increased stress generally will be sufficient to exceed the reduced yield stress of the seal element 52 for the deformation thereof effecting the fluid-tight sealing of the interfacing surfaces. Indeed, the seal element may be used to effect a hermetic seal which is especially useful in petrochemical and other applications to control the fugitive emission of VOC's and other pollutants. In service, it will be observed that the combination of a relatively incompressible retainer 12 and the relatively compressible seal element 52 provides a gasket construction which minimizes torque loss and thereby obviates much of the need for the periodic re- torquing of the members being joined. That is, it is well-known that gaskets of the type herein involved may develop a compression set which is manifested by fluid leaks as the tension in the joint is relaxed and the fluid-tight sealing of the interfacing surfaces is compromised, i this regard, the provision of bead portions 96 better ensures positive sealing, with retainer 12, in turn, synergistically providing generally a compression stop and non-yielding contact in establishing an alternative load torque path minimizing the compression set and leak potential of the gasket 50. Thus, the use of a retainer allows the mating parts to bear stress loads which otherwise would cause the deformation or extrusion of a gasket which lacked a retainer. In the case of a metal retainer 12, such contact additionally affords improved heat transfer between the interface surfaces, and also develops relatively high seal stresses for assured fluid-tight sealing of the interfacing structures. Thus, a unique gasket construction for automotive and other commercial, industrial, or military applications is described which is economical to manufacture even in complex shapes, and which exhibits reliable sealing properties. As it is anticipated that certain changes may be made in the present invention without departing from the precepts herein involved, it is intended that all matter contained in the foregoing description shall be interpreted in as illustrative rather than in a limiting sense. All references including any priority documents cited herein are expressly incorporated by reference.

Claims

CLAIMS What is claimed is:

1. A gasket assembly comprising: a retainer having extents in a radial direction and in an axial direction generally normal to the radial direction, the retainer including: a first section having opposing first section radial surfaces which extend to a first axial surface defined therebetween, the first axial surface having a length; a second section having opposing second section radial surfaces which extend to a second axial surface defined therebetween and defining with the first axial surface a gap between the first section and the second section, the second axial surface being disposed opposite the first axial surface along at least a portion of the length thereof to define a lengthwise extent of the gap, and being spaced-apart from the first axial surface along such portion to define a widthwise extent of the gap; at least one bridge portion disposed intermediate the lengthwise extent of the gap, the bridge portion spanning the widthwise extent of the gap and having a bridge first radial surface extending radially intermediate the first and the second axial surface of the first and the second section and being disposed axially intermediate the first radial surfaces of the first section and the second radial surfaces of the second section, and a bridge second radial surface disposed opposite the bridge first radial surface and extending radially intermediate the first and the second axial surface of the first and the second section, and being disposed axially intermediate the first axial surfaces of the first section and the second axial surfaces of the second section, the bridge first radial surface defining with the first and second axial surface a first groove portion within the gap, and the bridge second radial surface defining with the first and the second axial surface a second groove portion within the gap disposed opposite the first groove portion; a resilient seal element formed of an elastomeric material disposed within the gap, the seal element extending along at least a portion of the lengthwise extent of the gap and through the first and the second groove portion of the bridge portion.

2. The gasket assembly of claim 1 wherein the seal element has a first side attached to the first axial surface, and a second side attached to the second axial surface.

3. The gasket assembly of claim 1 wherein the seal element has a radial first sealing surface and a radial second sealing surface disposed opposite the first sealing surface.

4. The gasket assembly of claim 3 wherein seal element first sealing surface extends axially beyond the corresponding radial surfaces of the first and the second section, and wherein the seal element second sealing surface extends axially beyond the other radial surfaces of the first and second section.

5. The gasket assembly of claim 1 wherein the corresponding radial surfaces of the first and the second section are generally coplanar.

6. The gasket assembly of claim 4 wherein each of the seal element first and second sealing surface is configured as a bead.

7. The gasket assembly of claim 1 wherein the retainer is formed of a metal or plastic.

8. The gasket assembly of claim 1 wherein the elastomeric material forming the seal element is selected from the group consisting of natural rubbers and synthetic rubbers.

9. The gasket assembly of claim 1 wherein the gap lengthwise extent forms a generally closed geometry, and wherein the seal element extends along substantially the entirety of the gap lengthwise extent.

10. The gasket assembly of claim 1 wherein the retainer has an inner and outer perimeter, and wherein the gap is formed intermediate the retainer inner and outer perimeter.

11. The gasket assembly of claim 10 wherein the retainer inner and outer perimeter fonns a generally closed geometry.

12. The gasket assembly of claim 11 wherein the gap extends lengthwise generally about the closed geometry of the retainer.