GB178749A - Improvements in and relating to hydraulic pumps and transmission gear - Google Patents

Abstract

178,749. Hutchison, G. H., and McLean, D. S. June 1, 1921. Liquid-pressure engines. - In pumps and hydraulic transmission gear of the type in which pistons e reciprocate in revolving radial cylinders b and engage an annular track j, each piston is provided with a roller g, at or near the centre of the piston body, of diameter substantially equal to the internal diameter of the cylinder, so that the roller serves to take both the radial thrust between the piston and the track ring and the tangential thrust between the piston and the cylinder wall. The pistons are held in positive contact with the track ring, preferably by pins m which are held in extensions of the piston walls and project into grooves j<1> in the track ring. A bearing plate r pressed by small springs against the rotor face is preferably employed to prevent leakage of the working fluid from one side of the valve piece to the other. Passages x are provided to allow working fluid leaking past the valve end to pass into the casing. A thrust bearing v is provided to take axial thrust on the rotor, the driving shaft a<1> of which passes through an oiltight bush w.