In a motor vehicle suspension comprising suspension springs, a rotary acutator for stabilizing uneven deflections of the suspension springs, said rotary actuator comprising:
- housing means;
- first connecting rod means for connecting said housing means to a first load bearing portion of the motor vehicle suspension at a first side of the motor vehicle;
- shaft means, said shaft means defining a longitudinal axis;
- at least a portion of said shaft means being rotatably disposed within said housing means;
- second connecting rod means for connecting said shaft means to a second load bearing portion of a motor vehicle suspension at a second side of the motor vehicle;
- bearing means for rotatably mounting said at least a portion of said shaft means within said housing means for rotation of at least one of said shaft means and said housing means about said longitudinal axis with respect to the other of said shaft means and said housing means;
- said shaft means comprising an outer surface disposed towards said housing means;
- said housing means comprising an inner surface disposed towards said outer surface of said shaft means, said inner surface of said housing means being spaced apart from said outer surface of said shaft means to define a chamber between said shaft means and said housing means, said chamber having a first axial end and a second axial end;
- at least one of:
- said outer surface of said shaft means, and
- said inner surface of said housing means, comprising at least one projection extending towards the other of:
- said outer surface of said shaft means, and
- said inner surface of said housing means;
- said at least one projection extending from said first axial end of said chamber to said second axial end of said chamber to axially divide said chamber into a first chamber portion and a second chamber portion;
- said at least one projection comprising:
- a first side disposed towards said first chamber portion;
- a second side disposed opposite to said first side and adjacent said second chamber portion;
- a surface disposed between said first side and said second side, said surface being disposed towards the other of:
- said outer surface of said shaft means, and
- said inner surface of said housing means;
- and
- a longitudinal slot disposed in said surface, said longitudinal slot having two spaced apart side surfaces defining a width of said slot in a circumferential direction with respect to said longitudinal axis, said two spaced apart side surfaces extending substantially parallel to said longitudinal axis;
- at least one seal means disposed in said longitudinal slot for sealing between said first chamber portion and said second chamber portion to minimize fluid flow from said first chamber portion to said second chamber portion;
- said seal means having a width in a circumferential direction with respect to said longitudinal axis and a length along an axial direction with respect to said longitudinal axis;
- said width of said seal means being substantially less than said width of said slot to define a space between said seal means and at least one of said side surfaces of said slot along at least a substantial porion of the length of said seal means to permit flow of fluid between said seal means and said at least one side surface of said slot along at least a substantial portion of said length of said seal means;
- means for introducing fluid into at least one of:
- said first chamber portion, and
- said second chamber portion, to apply pressure to said at least one of:
- said first side of said projection, and
- said second side of said projection to relatively rotate said housing means and said shaft means;
- said longitudinal slot having a base portion and an open end defining a height of said slot in a radial direction with respect to said longitudinal axis and a first end and a second end defining the length of said slot in a direction substantially parallel to said longitudinal axis;
- said width of said seal means being configured to permit flow of fluid into said space along at least a substantial portion of the height of said slot and along at least a substantial portion of the length of said slot;
- said seal means having a first side surface disposed towards one of said side surfaces of said slot and a second side surface disposed towards the other of said side surfaces of said slot;
- only one side surface of said seal means at a time being in sealing engagement with its corresponding side surface of said slot during application of fluid pressure on said at least one projection to relatively rotate said housing means and said shaft means;
- said rotary actuator having a rest configuration with substantially no pressure being applied to said seal means;
- said seal means comprising a first edge surface disposed adjacent said base of said slot, a second edge surface disposed adjacent the open end of said slot, a first end disposed adjacent said first end of said slot and a second end disposed adjacent said second end of said slot;
- said seal means having a radial prestress between said base of said slot and said other of:
- said inner surface of said housing and said outer surface of said shaft means towards which said projection extends;
- said seal means in said rest configuration under said radial prestress having a barrel-shaped cross-section having a first width at said first and second edge surfaces thereof, and a second width between said first and second edge surfaces thereof, said second width being greater than said first width and less than said width of said slot;
- said first and second side surfaces comprising a plurality of axially disposed fluid passages spaced apart from one another and extending between said first and second edge surfaces;
- said first and second edge surfaces comprising at least one longitudinal fluid passage extending between said first and second ends;
- and
- said fluid passages dividing said side and edge surfaces of said seal means into a plurality of individual sealing surfaces.