Side seal for rotary combustion engine

Claim 2

A seal for a rotary combustion engine having a rotor member supported in a housing for compound rotary and radial motion with respect to a sidewall member, comprising: a seal element received within a groove formed in one of the members and having a continuous planar sealing surface engageable with a mating surface of said other of said members, said seal element being flexibly retained in said groove for permitting continuous conforming to said mating surface independent of thermal and pressure conditions in the engine; resilient means compressively retained in said groove for biasing said sealing surface into operative sealing engagement with said mating surface; and a multiple thread groove formed in said sealing surface defined by a spiral lip, the surfaces of said lip generating viscous shear forces during rotary motion of the rotor member and acting as wiping blades during radial motion of the rotor member for returning leaking fluid to the crankcase.

Claim 3

In a rotary combustion engine having a rotor eccentrically rotatable within a cavity so as to establish a plurality of variable volume working chambers, said cavity being defined by axially spaced sidewalls and said rotor having an annular groove formed in an axially facing surface thereof adjacent the sidewalls that terminates in an annular undercut notch, a side seal for preventing the flow of fluid from the engine crankcase to the working chambers, comprising: a flexible sealing annulus receivable within the confines of the groove, said sealing annulus being L-shaped in cross section and including an annular radial sealing flange and a cylindrical axial support sleeve, the latter of which has a clearance with an inner portion of the groove to permit limited radial movement of the sealing annulus; an outwardly projecting circumferential bead formed on the support sleeve and located in the notch for axially retaining the sealing annulus on the rotor while accommodating limited flexure of said sealing flange into continuous sealing conformity with the sidewalls thereby minimizing surface distortions in the sealing surface due to thermal and pressure variations in the engine; an elastomeric biasing ring of rectangular cross section compressively retained between the base of the groove and the sealing flange, said biasing ring serving in conjunction with fluid pressure to urge said sealing flange into operative engagement with the sidewalls; and a spiral groove formed in said sealing flange and defined by a multiple thread helical lip, the spiral groove having portions thereof generating hydrodynamic forces during rotary movement of the rotor to repel leakage and the lip mechanically wiping the sidewalls during radial movement of the rotor to direct leaking fluid toward the crankcase.

Claim 4

In a rotary combustion engine having a rotor eccentrically rotatable within a cavity so as to establish a plurality of variable volume working chambers, said cavity being defined by axially spaced sidewalls and said rotor having an annular groove formed in an axially facing surface thereof adjacent the sidewalls that terminates in an annular undercut notch, a side seal for preventing the flow of fluid from the engine crankcase to the working chambers, comprising: a flexible sealing annulus receivable within the confines of the groove, said sealing annulus being L-shaped in cross section and including an annular radial sealing flange and a cylindrical axial support sleeve, the latter of which has a clearance with an inner portion of the groove to permit limited radial movement of the sealing annulus; an outwardly projecting circumferential bead formed on the support sleeve and located in the notch for axially retaining the sealing annulus on the rotor while accommodating limited flexure of said sealing flange into continuous sealing conformity with the sidewalls thereby minimizing surface distortions in the sealing surface due to thermal and pressure variations in the engine; an elastomeric biasing ring of rectangular cross section compressively retained between the base of the groove and the sealing flange, said biasing ring serving in conjunction with fluid pressure to urge said sealing flange into operative engagement with the sidewalls; and a spiral groove formed in said sealing flange and defined by a multiple thread helical lip, the spiral groove having portions thereof generating hydrodynamic forces during rotary movement of the rotor to repel leakage and the lip mechanically wiping the sidewalls during radial movement of the rotor to direct leaking fluid toward the crankcase.