A variable displacement hydraulic/pump motor has a yoke with a pair of shafts
aligned
to define a yoke pivot axis and connected to a valve plate therebetween having
intake and discharge apertures. A rotatable cylinder barrel has piston cylinders
open at one end to receive a piston head and opening through fluid ports at another
end, flush against the valve plate surface. A drive block is mounted on an input/output
shaft for rotation about a central axis of rotation inclined at an angle relative
to the longitudinal axis of the cylinder barrel which may be changed by a drive
engaging the yoke at a point near its pivot axis. Loads on bushings supporting
the yoke shafts are reduced by providing radially extending fluid ports in the
shafts and in communication with the intake and discharge apertures of the valve plate.