Wobble plate control for a variable piston displacement machine

Claim 1

In a variable displacement wobble plate drive machine having a frame; a shaft mounted for rotation about a shaft axis in the frame; a support member defining a driving axis arranged to intersect the shaft axis at a common point, said support member mounted for rotation with the shaft; means for varying the angle between the driving axis and the shaft axis; a wobble plate; and means connecting the wobble plate to the support member for wobbling movement of the plate responsive to the wobble of the driving axis as the shaft rotates, an improved wobble plate restraint mechanism wherein the support member is mounted for rotation about a tilted axis which intersects the shaft axis at said common point at a first acute angle, and the mechanism further comprises an element fixed to the frame and having a fixed conical surface arranged symmetrically about the shaft axis, an idler element mounted for rotation about the shaft on the tilted axis, having a first conical surface arranged symmetrically about said tilted axis and engaging said fixed conical surface for rolling movement of the first conical surface on the fixed conical surface as the shaft rotates, thereby forming a constant velocity coupling from the idler element to the frame; and a second conical surface arranged symmetrically about the tilted axis, and a wobble plate conical surface engaging said second conical surface for rolling movement of the wobble plate conical surface on the second conical surface as the angle between the driving axis and the shaft axis is varied, and the apices of said conical surfaces being disposed at said common point, thereby forming a constant velocity coupling from the wobble plate to the frame.