Return to neutral device for a hydraulic apparatus

摘要

In a hydrostatic device using an axial piston pump, a yoke is mounted so that it contacts the movable swash plate of the hydrostatic transmission. The yoke is biased by a spring-type mechanism to force the swash plate to return to neutral, and the set position of the yoke plate may be externally adjusted. A bias or load arm rotatably fixed to a housing at one end and connected to a spring at the other end is engaged to the yoke to provide the return force to the yoke plate. The yoke plate may have two legs to provide a return to neutral force to the swash plate in either direction, or one leg to provide the return to neutral force in only a single direction.

主权项

1. A hydraulic drive apparatus, comprising:
a housing; a rotatable cylinder block disposed in the housing and having a plurality of pistons disposed therein; a swash plate disposed in the housing and engaged to the plurality of pistons for controlling an output of the cylinder block, the swash plate comprising a first stop having a first pocket formed thereon; a first return member disposed in the housing and having a first end defining a first axis about which the first return member is pivotable, a second end, and a second pocket formed therein between the first end and the second end; and a second return member engaged to the first return member and comprising:
at least a first contact arm positioned to contact the first stop on the swash plate, the first contact arm having a curved surface shaped to fit in the first pocket, wherein the first contact arm provides a return force to the swash plate through the first stop when the swash plate is stroked in a first direction; anda protuberance shaped to fit in the second pocket to permit the second return member to pivot with respect to the first return member about a second axis parallel to the first axis.