Valve stem seal

Claim 2

A valve stem seal for an internal combustion engine having a valve stem axially reciprocable relative to a valve guide comprising: a circular elastomeric sealing ring having a planar lower surface engageable with an upper surface of the valve guide, said sealing ring having a centrally located aperture defined by a low angle frustoconical surface which converges upwardly and inwardly from said lower surface; and upper surface on said sealing ring defined by a wide angle frustoconical surface which is coaxial with and converges upwardly and inwardly toward said aperture and intersects said low angle frustoconical surface to define a sharp seal lip which has a diametrical interference with the valve stem for establishing sealing contact with the latter; and a retaining member having an aperture formed therein and adapted to be telescopically received over said valve stem and said sealing ring, said retaining member having a frustoconical surface compressively engaging said upper surface of said sealing ring in assembly for radially inwardly biasing the seal lip and thereby maintaining said sealing contact with said valve stem within predetermined limits of eccentricity between the latter and said valve guide.

Claim 3

A two-piece valve stem seal for preventing the passage of oil between a valve guide and a valve stem axially reciprocably mounted therein, comprising: a metallic cup-shaped retaining cap having a frustoconical top which has a relatively large approach angle with respect to the longitudinal axis of said valve stem and a downwardly depending cylindrical sleeve including a corrugated interior surface which is adapted to frictionally grip an outer surface of the valve guide in assembly; a circular elastomeric sealing ring adapted to be received within said retaining cap and having a planar base located in a plane substantially normal to said axis and engageable in assembly with an upper surface of said valve guide; an upper frustoconical surface formed in said sealing ring and converging upwardly and inwardly from said base toward the axis with an approach angle substantially equal to said approach angle of the top of said retaining cap; a central aperture defied by an inner frustoconical surface formed in said sealing ring coaxially with said upper frustoconical surface and converging upwardly and inwardly from said base toward the axis with a relatively low approach angle, said inner frustoconical surface intersecting said upper frustoconical surface at a sharp radially inwardly facing seal lip which has a diametrical interference with said valve stem for establishing sealing contact therewith, said sealing ring being axially cOmpressively loaded between said retaining cap and said valve guide in assembly whereby said seal lip is radially inwardly biased into sealing contact with said valve stem within predetermined limits of eccentricity between the latter and said valve guide.

Claim 4

A two-piece valve stem seal for preventing the passage of oil between a valve guide and a valve stem axially reciprocably mounted therein, comprising: a metallic cup-shaped retaining cap having a frustoconical top which has a relatively large approach angle with respect to the longitudinal axis of said valve stem and a downwardly depending cylindrical sleeve including a corrugated interior surface which is adapted to frictionally grip an outer surface of the valve guide in assembly; a circular elastomeric sealing ring adapted to be received within said retaining cap and having a planar base located in a plane substantially normal to said axis and engageable in assembly with an upper surface of said valve guide; an upper frustoconical surface formed in said sealing ring and converging upwardly and inwardly from said base toward the axis with an approach angle substantially equal to said approach angle of the top of said retaining cap; a central aperture defied by an inner frustoconical surface formed in said sealing ring coaxially with said upper frustoconical surface and converging upwardly and inwardly from said base toward the axis with a relatively low approach angle, said inner frustoconical surface intersecting said upper frustoconical surface at a sharp radially inwardly facing seal lip which has a diametrical interference with said valve stem for establishing sealing contact therewith, said sealing ring being axially cOmpressively loaded between said retaining cap and said valve guide in assembly whereby said seal lip is radially inwardly biased into sealing contact with said valve stem within predetermined limits of eccentricity between the latter and said valve guide.

Claim 5

In an internal combustion engine having a valve stem axially reciprocable relative to a valve guide and sealed by a two-piece valve stem seal which comprises a circular elastomeric sealing ring located in a plane having a base substantially normal to the longitudinal axis of said valve stem and engageable with an upper surface of said valve guide in assembly; an upper frustoconical surface formed in said sealing ring and converging upwardly and inwardly from said base toward said axis with an approach angle of approximately 60*, said sealing ring having a central frustoconical aperture formed therein converging upwardly and inwardly from said base toward said axis with an approach angle of approximately 10*, said aperture intersecting said upper frustoconical surface at a sharp radially inwardly facing seal lip having a diametrical interference with said valve stem in assembly when received over the latter with said base engaging said upper surface of said valve guide; a metallic cup-shaped retaining cap having a frustoconical top portion which has an approach angle with respect to said axis of said seal approximately 60*, said retaining cap including a downwardly depending cylindrical sleeve having a plurality of circumferentially spaced indentations formed therein defining a corrugated interior surface adapted to frictionally engage an outer surface of the valve guide in assembly so that said sealing ring is axially compressively loaded between said top portion of said retaining cap and said upper surface of said valve guide whereby said seal lip is radially inwardly biased into sealing contact with said valve stem to prevent the passage of oil between the latter and said valve guide and maintain said sealing contact within predetermined limits of eccentricity between said valve stem and valve guide.

Claim 6

In an internal combustion engine having a valve stem axially reciprocable relative to a valve guide and sealed by a two-piece valve stem seal which comprises a circular elastomeric sealing ring located in a plane having a base substantially normal to the longitudinal axis of said valve stem and engageable with an upper surface of said valve guide in assembly; an upper frustoconical surface formed in said sealing ring and converging upwardly and inwardly from said base toward said axis with an approach angle of approximately 60*, said sealing ring having a central frustoconical aperture formed therein converging upwardly and inwardly from said base toward said axis with an approach angle of approximately 10*, said aperture intersecting said upper frustoconical surface at a sharp radially inwardly facing seal lip having a diametrical interference with said valve stem in assembly when received over the latter with said base engaging said upper surface of said valve guide; a metallic cup-shaped retaining cap having a frustoconical top portion which has an approach angle with respect to said axis of said seal approximately 60*, said retaining cap including a downwardly depending cylindrical sleeve having a plurality of circumferentially spaced indentations formed therein defining a corrugated interior surface adapted to frictionally engage an outer surface of the valve guide in assembly so that said sealing ring is axially compressively loaded between said top portion of said retaining cap and said upper surface of said valve guide whereby said seal lip is radially inwardly biased into sealing contact with said valve stem to prevent the passage of oil between the latter and said valve guide and maintain said sealing contact within predetermined limits of eccentricity between said valve stem and valve guide.