A torque control for a hydrostatic piston pump that provides for a servo
piston rod that is connected to the swashplate of the pump and connected
to a servo piston within a first cavity that receives compensation
pressure that urges the servo piston toward the swashplate. The servo
piston has a stem that extends into a bore and is in contact with the
stem of a maximum displacement piston that extends into a second cavity
that is acted upon by system pressure to urge the maximum displacement
piston toward the swashplate. Additionally, within the second cavity is a
set of Bellville washers that surround the stem of the maximum
displacement piston to limit the movement of the maximum displacement
piston toward the swashplate.