US3531134A - Seal retainer - Google Patents

Description

P 29, 1970' J. H. KAMMERAAD 3,531,134 I SEAL RETAINER Filed June 6, 1969 I as 3/ 34 I I l'lG. /0/6 A/ %%%0 y 4J0, M

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United States Patent US. Cl. 277-181 8 Claims ABSTRACT OF THE DISCLOSURE A metallic boot for retaining a valve stem seal in abutment with the protruding shoulder formed integrally with an engine head. The boot has a permanently deformable lip or indent extending inwardly about its entire periphery and this indent deforms permanently to accommodate minor dimensional variations in the shoulder when the boot is slid telescopically thereon.

This application is a continuation-in-part of copending application Ser. No. 627,206, filed Mar. 30, 1967, now abandoned.

BACKGROUND This invention relates to seal retainers and, more particularly, to seal retainers adapted for utilization in conjunction with a shaft housing having an exposed shoulder portion.

It is often desirable to positively position an oil seal or the like about a shaft in fixed, spatial relationship with respect to the housing Within which the shaft rotates or reciprocates. For example, in the typical overhead valve internal combustion engine, some type of oil seal must be provided to prevent oil from flowing between the valve stem and the valve guide or housing into the combustion cylinder in an uncontrolled manner. A number of relatively successful seals have been developed for performing this function, but a problem which has plagued engine manufacturers consistently is the retention of the seal in abutment with the valve guide or housing at the point where the shaft emerges therefrom so as to positively prevent undesirable oil leakage.

The heads of internal combustion engines of this type are usually formed with an integrally cast, exposed shoulder portion opposite the valve seat around which the valve spring may be positively positioned. Customarily, the seal is placed over the valve stem and abuts the upper surface of this shouldered portion within the interior of the valve'spring. The problems which have been incurred in retaining the seal in the desired position are generally attributed to (-1) the relatively high operating temperatures which render many types of otherwise suitable materials extremely malleable, if not liquid; and (2) the somewhat inconsistent peripheral dimensions'of the shoulder portion, even after machining, which render satisfactory engagement of a mass-produced retainer thereabout almost impossible unless the retainer is fabricated from a flexible material. I

In order to alleviate that portion of the problem attributable to varying peripheral dimensions, manufacturers have turned to the use of a flexible synthetic boot fabricated from 'Teflon or other types of polyacrylic material. Usually, the boot fits around the valve stem, over the top of the seal and resiliently engages the outer wall of the exposed shoulder portion of the valve guide. The results obtained with such synthetic boots have not been particularly satisfactory due to the tendency of the flexible material to deform under high-temperature operating conditions and, also due to the seemingly inescapable fouling Patented Sept. 29, 1970 ice of the boot within the valve spring. The former phenomenon causes the materials to stretch or become otherwise highly malleable and, thus, allows the seal to reciprocate to some extent with the valve stem so that oil in undesirably high quantities can find its way into the valve guide. The latter phenomenon, of course, interferes with the proper seating of the valve and, thus, reduces engine efficiency markedly.

OBJECTS AND SPECIFICATION It is an object of this invention to provide a seal re tainer which is not subject to the disadvantages outlined above.

More particularly, it is an object of this invention to provide a seal retainer which may be mass produced to a common specification and, yet, which will positively position a seal at the desired position despite minor peripheral dimension variations in the shoulder or the like to which it engages.

It is an object of this invention to provide a device of the type described which will not deform under ordinary or extreme temperature conditions within an internal combustion engine.

It is an object of this invention to provide a seal retainer particularly adapted for utilization in conjunction with a valve seal which will not foul with and, thus, detrimentally affect the operating characteristics of the valve spring.

It is an object of this invention to provide a device of the type described which automatically adjusts to accommodate varying peripheral dimensions of the exposed shoulder of a valve guide so as to insure proper and stable engagement therewith.

These, as well as other objects of this invention, will be readily understood by those skilled in the art with reference to the following specification and accompanying figures in which:

FIG. 1 is a fragmentary, cross-sectional view of a typical internal combustion head showing the valve stem seal retained by the device which is the subject of this invention;

FIG. 2 is a cross-sectional view taken along plane II- II of FIG. 1;

FIG. 3 is a fragmentary, cross-sectional view of the exposed shoulder portion of a valve guide illustrating particularly the manner in which the valve retainer assembly will deform to accommodate shoulders of varying peripheral dimension;

:FIG. 4 is a cross-sectional view of the seal retainer blank; and

FIG. 5 is a cross-sectional view of a modified form of seal blank.

Briefly, this invention contemplates the utilization of two telescopically interfitting parts, one of said parts having associated therewith means for holding an operative component such as a valve seal and the other of said parts forming an integral segment of a housing within which a shaft or the like is movably positioned. Permanently deformable means are provided on that part associated with the seal retainer or the like for automatically accommodating minor variations in the dimensions of the integral housing part when the two parts are telescopically interfitted to insure that the two parts will remain positively engaged with respect to one another once they have been telescopically interfitted during the assembly process.

In its more limited aspects, this invention comprises a valve structure having a valve guide with an exposed shoulder portion, a valve stem reciprocally mounted within the guide and a seal surrounding the stem and abutting the surface of the shoulder portion. Means are provided for retaining the seal in said abutting relationship comprising a tubular base member adapted to fit over and engage said shoulder portion. The base member has a deformable indent extending inwardly from the side wall thereof adapted to permanently deform to accommodate minor variations in the peripheral measurements of the shoulder portion to insure the solid engagement of said base member therewith. Means are associated with the base member for holding the seal in fixed, spatial relationship with respect thereto and, thus, in abutment with the surface of said shoulder portion.

Referring now to the figures, a preferred embodiment of this invention will be described in detail. FIG. 1 illustrates a typical overhead valve engine head having machined therein a valve guide 11. Valve guide 11 has an exposed shoulder portion indicated generally by the reference numeral 12 through which the valve stem 13 is passed during assembly. Oridinarily, the exposed shoulder 12 will be integrally cast with the remainder of the head and thereafter machined to proper dimension. A valve spring 14 encircles exposed shoulder portion 12 of the valve guide assembly and the valve is conventionally retained with respect thereto by a pair of valve keepers 15. While not shown, of course, the valve stem 13 extends downwardly as shown in FIG. 1 and terminates in a valve portion having a suitable seat machined into the lower surface of the head 10. The valve spring 14 retains the valve in closed relationship with respect to the seat, except when forced downwardly by a rocker arm or the like.

The striking of the rocker arm against the upper surface of the valve and the reciprocation of the valve stem Within the guide require that oil be supplied to the upper section of the valve stem. This is usually accomplished by means of an oil passage in the rocker arm. Pumping of the oil over the upper section of the valve stem necessitates the provision of an oil seal to prevent undesirable quantities of oil from flowing between the valve stem 13 and the valve guide 11 into the combustion chamber of the engine. Such a seal is shown at 16 in FIG. 1 and may be fabricated conveniently in accordance with the teachings of US. Pat. No. 3,069,175 to R. L. Skinner or in accordance with the teachings of copending application Ser. No. 675,586 filed Oct. 16, 1967. Preferably, seal 16 rests in abutting relationship upon the upper surface of exposed shoulder portion 12 and, since the valve stem 13 is continually reciprocating, some means must be provided for retaining it in that position.

As noted previously, seal retainers available heretofore have not performed satisfactorily because of their tendency to foul the proper action of the valve spring 14 or, alternatively, to break down under high temperatures and allow the oil seal 16 to pull away from its abutting position on shoulder 12. This, in turn, allows oil to seep through the valve guide into the combustion chamber. The problem is particularly aggravated since a pressure differential is created between the opposite ends of the valve stem 13 during the intake stroke of the piston which tends to force the oil downwardly along the valve stem and into the combustion chamber.

In accordance with the teachings of this invention, the proper positioning of the seal 16 is maintained by means of a seal retainer 20 (see FIGS. 1, 2, 3 and 4) having a cylindrical wall section 21 and an expanded seal receptacle 22. The upper edge of the seal receptacle 22 is rolled over, as indicated at 23, after the seal 16 has been inserted therein. Intermediate the axial extremities of the tubular wall section 21 is located a deformable indent 24 which, conveniently, may be fabricated directly into the blank (see FIG. 4) by means of an eyelet machine,

screw machine or the like. The axial measurement (or height as viewed in FIG. 1) of the derfomable indent is substantially less than the axial measurement (or height as viewed in FIG. 1) of the tubular wall section 21. The tubular wall section (which may or may not be cylindrical depending upon the peripheral shape of exposed shoulder portion 12) is fabricated from a metallic substance such as drawing quality steel having elasticity properties such that the indent 24 will deform in a substantially permanent manner when forced upon the valve guide. It has been found, for example, that an aluminized drawing quality steel having a thickness approximately 0.015 inch performs satisfactorily. Best results are obtained when the material has been cold rolled and cold finished. Other materials such as die cast zinc, brass, aluminum or die cast aluminum may be satisfactory depending upon the operating environment.

Referring now particularly to FIG. 4, assume that the exposed shoulder portion of the valve guide upon which the seal is to be retained is cylindrical in outer peripheral shape. Assume further, and incidentally quite realistically, that the peripheral dimensions of the exterior portion of the shoulder can be controlled during fabrication within limits of approximately 0.015 inch. In this particular case, the blank will be formed such that the measurement 25 (between facing portions of the deformable indent 24) is approximately 0.015 inch less than the measurement 26 between the interior facing sections of cylindrical walls 21.

If the particular exposed shoulder portion 12 upon which the seal retainer 20 is telescopically fitted has exterior dimensions of minimum value (see FIG. 1), the most inwardly extending sections 27 of the deformable indents 24 will abut the periphery of the shoulder portion with little permanent deformation as the seal retainer is pressed onto the shoulder. Sufficient engagement will be effected, however, to positively position the seal retainer 20 with respect to the shoulder 12 and, thus, to positively retain the seal 16 in abutting relationship with the upper surface of shoulder portion 12 and to prevent oil from flowing upwardly between indent 24 and the sections of shoulder 12 which it abuts. If, on the other hand, as illus trated in FIG. 3, the outer peripheral measurements of the shoulder portion 12 are of maximum size, the deformable indent 24 will be pressed permanently outwardly into a snug relationship with the shoulder portion as the retainer 20 is telescopically forced thereover and the interior of the cylindrical wall section 21 will come nearly into abutment with the outer periphery of shoulder portion 12.

The term permanently, as utilized throughout this specification and the appended claims, means that the substance from which the tubular wall section is fabricated should deform upon installation onto an oversize valve guide shoulder such as shown in FIG. 3 in such a manner that, if withdrawn after installation, it will retain approximately an identical configuration to that shown in FIG. 3, there being little tendency for it to resume its original configuration. It is preferable, in this regard, that the measurement between the interior facing secions of the cylindrical walls 21 (26 in FIG. 4) be slightly greater than the outer peripheral dimensions of the exterior portions of the valve guides upon which it is to be placed. The clearance thus provided, between the walls 21 and the guide, will prevent or substantially retard any tendency of those portions of the retainer 20 other than the deformable indent from deforming when the retainer is installed.

Preferably, the deformable indent 24 extends about the entire inner periphery of the retainer 20 to provide an oil seal between shoulder 12 and the indent. This seal, of course, prevents the oil from traveling upwardly as viewed in FIG. 1 between the boot and the shoulder and then down into the valve guide beneath seal 16. Such is not absolutely necessary, however, in all applications and mere deformable nipple indentations may provide satisfactory results. The structure as shown, however, is of particular value since the retainer will engage the shoulder portion about its entire periphery to more positively position it with respect thereto and also serve as a seal. This is true regardless of whether the peripheral dimension variations in the shoulder portion are merely diametrical in nature or whether the peripheral measurements are slightly out of round. In the latter case, of course, certain sections of the deformable indent will deform outwardly to a greater extent than othersections thereof when the retainer is telescopically forced over and into engagement with the shoulder portion. Similar comments are true regardless of the basic desirable peripheral shape of the shoulder portion 12 and its mating seal retainer. Thus, the word tubular as utilized in this specification and the accompanying claims is not limited to cylindrical configurations.

The retainer which is the subject of this invention can be placed in position on the exposed shoulder portion of the valve guide by merely tipping it downwardly thereover. Best results are obtained by using a cylindrical tool circumscribing the valve stem (prior to installation of the Spring) with a base contacting the upper surface of the retainer. In such a situation, of course, the valve stem acts as a guide to assist in proper positioning of the retainer. The seal will be installed in the retainer, ordinarily, prior to placement of the assembly on the valve guide.

A modified form of the invention is illustrated in FIG. and comprises a seal retainer 30 having tubular side walls 31 with an expanded seal receptacle 32 afiixed thereto in substantially the same manner as discussed previously. In the embodiment shown in FIG. 5, however, the deformable indent 34 comprises an inwardly turned lip 35 at the lower axial extremity of the retainer. When such a device is telescopically forced over and onto the shoulder 12, the inwardly turned lips 35 deform outwardly to accommodate and coincide with the dimensional variations at the periphery of the shoulder. Again, positive engagement is effected about the entire periphery of the seal retainer.

The salient features of the invention will be readily apparent to those skilled in the art. Never before has it been possible to utilize a material such as steel as a shoulder-conforming seal retainer, because of unavoidable variations in the peripheral measurements of the receiving shoulder portion of the valve guide. Thus, attention has been directed toward resilient forms of synthetic materials and their inherently low melting point characteristics have been tolerated. The present invention, on the contrary, provides a seal retainer which is relatively unaffected by operating temperatures within an internal combustion engine and, thus, which will retain the seal at the desired location during all phases of engine operation. The seal retainer can be fabricated more economically than its resilient boot-like predecessor and, additionally, has an expected life comparable to that of the engine itself.

While the invention has been illustrated in conjunction with a particular type of oil seal, it will be readily appreciated by those skilled in the art that other types of seals may be utilized by merely changing the configuration of the expanded seal receptacle at the upper extremity of the retainer. Preferably, of course, the seal will be of a type which allows for lateral eccentrieities in the valve stem movement, but regardless of whether this class of seal is utilized, it can be positively positioned at a given location by utilizing the teachings of the instant invention.

While a preferred form of this invention has been illustrated in detail, along with a minor modification thereof, it will be obvious to those skilled in the art that many other modifications may be conceived and fabricated without departing from the spirit and scope of this specification and the accompanying drawings. Such other embodiments are to be deemed as included in the following claims unless these claims, by their language, expressly state otherwise.

I claim:

1. In an internal combustion engine having a valve structure including a valve guide with an exposed shoulder portion, the peripheral measurements of which may vary slightly from one guide to another; a valve stem reciprocally mounted within said guide; a seal surrounding said stem and abutting the surface of said shoulder portion; and means for retaining said seal in said abutting relationship, the improvement in said last mentioned means comprising:

a metallic tubular base member adapted to fit telescopically over said valve guide shoulder portion, said base member having a permanently deformable indent extending inwardly from the side wall thereof to engage said valve guide shoulder portion, the axial measurement of said indent being substantially less than the axial measurement of said side wall, said indent adapted to deform permanently to accommodate the possible slight variations in the peripheral measurements of said valve guide shoulder portion to insure the engagement of said base member thereto, said deformable indent extending about the entire periphery of said tubular base member such that said indent will engage said valve guide shoulder portion about its entire periphery to seal against leakage of oil between said base member and said shoulder portion; and

means associated with said base member for holding said seal in fixed spatial relationship with respect thereto and, thus in abutment with the surface of said shoulder portion.

2. The structure as set forth in claim 1 wherein said deformable indent is spaced intermediate the axial extremities of said base member.

3. The structure as set forth in claim 2 wherein said shoulder portion is generally cylindrical and wherein said base member comprises a generally cylindrical wall section having an intermediate peripheral portion thereof projecting inwardly both on the interior and exterior surfaces of said wall section to define said deformable indent.

4. The structure as set forth in claim 1 wherein said deformable indent is positioned adjacent one of the axial extremities of said base member.

5. The structure as set forth in claim 4 wherein said indent comprises a lip formed integrally with said base member and curling inwardly from one of the axial extremities thereof.

6. The structure as set forth in claim 1 wherein said base member, said indent and said holding means are formed integrally from metallic stock.

7. In an internal combustion engine having a valve structure including a valve guide with an exposed shoulder portion, the peripheral measurements of which may vary slightly from one guide to another; a valve stem reciprocally mounted within said guide; a seal surrounding said stem and abutting the surface of said shoulder portion; and means for retaining said seal in said abutting relationship, the improvement in said last mentioned means comprising:

a tubular base member adapted to fit telescopically over said valve guide shoulder portion, said base member having a deformable indent extending in wardly from the side wall thereof to engage said shoulder portion, the axial measurement of said indent being substantially less than the axial measurement of said side wall, said indent adapted to deform to accommodate the possible slight variations in the peripheral measurements of said valve guide shoulder portion to insure the engagement of said base member thereto, said base member being fabricated from drawing quality steel, said deformable indent extending about the entire periphery of said tubular base member such that said indent will engage said valve guide shoulder portion about its entire pe References Cited riphery to seal against leakage of oil between said UNITED STATES PATENTS base member and said shoulder portion; and

means associated with said base member for holding 487,434 12/1892 f said seal in fixed spatial relationship with respect r 3,379,445 4/1968 Fls her 277 178 thereto and, thus, in abutment with th surface of 3,450,411 6/ 9 9 Skmner 277 48 said shoulder portion. 642,428 1900 Cevolanl.

8. The structure as set forth in claim 1 wherein the inner dimensions of said base member excepting said in- SAMUEL ROTHBERG Pnmary Exammer dent exceed the maximum outer dimensions of said ex- 10 U S Cl X R posed shoulder portion whereby said portion will be contacted by said indent only. 123l89; 277-48, 189

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