Revolving yoke load-sensitive displacement-varying mechanism for axial piston hydraulic pump

Abstract

A revolving yoke load-sensitive displacement-varying mechanism for axial piston hydraulic pump, the mechanism including a housing and a pump shaft with a first transverse opening approximately in a central portion of the pump shaft and a fluid passageway within the pump shaft approximately parallel to a longitudinal axis of the pump shaft. The pump shaft includes means to receive rotary motion from an energy source. The fluid passageway connects a front end of the pump shaft with the first transverse opening and continues beyond the transverse opening into a rear portion of the pump shaft. A swash plate and a yoke are formed as a single member and have a second transverse opening that is substantially coaxial with the first transverse opening. A yoke axis is oriented such that the yoke is stabbed over the pump shaft and the yoke axis is inserted into the first and second transverse openings to enable a partial rotation of the yoke about the yoke shaft. The yoke and yoke axis allow for unobstructed flow of a working fluid in both directions while preventing a loss of the working fluid into an internal space of the housing. The rear portion of the pump shaft includes means to utilize changes of a pressure of the working fluid towards automatic change of an angle of the yoke with respect to a longitudinal axis of the pump shaft.

1 . A revolving yoke load-sensitive displacement-varying mechanism for axial piston hydraulic pump, the mechanism comprising: 
 a housing;    a pump shaft with a first transverse opening approximately in a central portion of the pump shaft and a fluid passageway within the pump shaft approximately parallel to a longitudinal axis of the pump shaft, the pump shaft further comprising means to receive rotary motion from an energy source,    wherein the fluid passageway openly connects a front end of the pump shaft with the first transverse opening and continues beyond the transverse opening into a rear portion of the pump shaft;    a swash plate and a yoke formed as a single member and having a second transverse opening that is substantially coaxial with the first transverse opening;    a yoke axis, wherein the yoke is stabbed over the pump shaft and the yoke axis is inserted into the first and second transverse openings to enable a partial rotation of the yoke about the yoke shaft,    wherein the yoke and yoke axis allow for unobstructed flow of a working fluid in both directions from a pressurized discharge cavity of a pump through the fluid passageway via the first transverse opening and further into the rear portion of the pump shaft while preventing a loss of the working fluid into an internal space of the housing,    wherein the rear portion of the pump shaft comprises a sequence of means to utilize changes of a pressure of the working fluid towards automatic change of an angle of the yoke with respect to a longitudinal axis of the pump shaft;    means to prevent the loss of the working fluid from the pressurized discharge cavity of the pump into the internal space of the housing and from the internal space of the housing.