Patent ID: 8500423
Filing Date: 2013-08-06
Classification: F04C

Abstract:
1. A rotary fluid pressure device comprising: a housing; a ring gear attached to said housing and defining an interior extending along a longitudinal axis, and including a plurality of internal teeth extending radially inward into said interior; a star gear eccentrically disposed relative to said longitudinal axis within said interior of said ring gear for orbital movement about said longitudinal axis, said star gear including a plurality of external teeth extending radially outward into engagement with said internal teeth of said ring gear and defining an internal opening; a spacer ring attached to said star gear and disposed within said internal opening of said star gear adjacent an end surface of said star gear for orbital movement with said star gear about said longitudinal axis; a brake pin coupled to said housing and longitudinally moveable along said longitudinal axis between a locked position and an unlocked position with said brake pin in interlocking engagement with said spacer ring to prevent said orbital movement of said spacer ring and said star gear when in said locked position and said brake pin disengaged from said spacer ring to permit said orbital movement of said spacer ring and said star gear when in said unlocked position; a biasing device coupled to said brake pin and configured for biasing said brake pin into said locked position; said spacer ring including an interior surface extending along and angled relative to said longitudinal axis at a taper angle to define a frustoconical taper opening toward said brake pin; and said brake pin including an outer surface extending along and angled inward toward said longitudinal axis at said taper angle to define a frustoconical surface narrowing toward said spacer ring for engaging said interior surface of said spacer ring in a tapered engagement; wherein said tapered engagement generates an axial force along said longitudinal axis sufficient to compress said biasing device and move said brake pin into said unlocked position in response to a torque applied to said star gear having a magnitude greater than a pre-defined value; and wherein said star gear includes a plurality of internal splines defining a spline diameter, with said outer surface of said brake pin being smaller than said spline diameter such that the outer surface of said brake pin is radially spaced from said internal splines of said star gear relative to said longitudinal axis.