Patent ID: 7895834

Claim:
A hydraulic stepless transmission comprising: a variable displacement type hydraulic pump; and a variable displacement type hydraulic motor connected to the hydraulic pump by a hydraulic circuit, wherein the hydraulic pump includes: a first hydraulic servo mechanism for regulating swash plate angles of movable swash plates of the hydraulic pump to control output rotations of the respective hydraulic pump; and a first load control mechanism for both forward and reverse travel and for controlling the first hydraulic servo mechanism to a speed reducing side to turn the swash plate of the hydraulic pump in a speed reducing direction through the first hydraulic servo mechanism when pressure in the hydraulic circuit is high, wherein the hydraulic motor includes: a second hydraulic servo mechanism for regulating swash plate angles of movable swash plates of the hydraulic motor to control output rotations of the hydraulic motor; and a second load control mechanism for both forward and reverse travel and for controlling the second hydraulic servo mechanism to a speed reducing side to turn the swash plate of the hydraulic motor in a speed reducing direction through the second hydraulic servo mechanism when pressure in the hydraulic circuit is high, and wherein feedback pressures are introduced into each of the first and second load control mechanisms from a first portion of the hydraulic circuit that is a discharge side of the hydraulic pump in the forward travel and a second portion of the hydraulic circuit that is a discharge side of the hydraulic pump in backward travel.