Abstract

A hydrostatic variator having a common yoke design and two or more bent axis piston drive units is disclosed in which the rotating group of a drive unit is arranged to be movable relative to the yoke to alter the angle between its drive shaft axis and rotating group axis independent of the other drive unit. This can be accomplished using movable sector plates coupled to the rotating groups that are arcuately movable within the yoke about the axis perpendicular to the respective drive shaft axes of the drive units. Such variators enjoy the response and packaging advantages of a common yoke design while still allowing dynamic adjustment of system size. In turn, varying system size allows for efficiency to be improved at conditions other than at the maximum design torque.

IPC Classes  ?

• F16H 61/423 - Motor capacity control by fluid pressure control means
• F16H 61/433 - Pump capacity control by fluid pressure control means
• F16H 39/08 - Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit pump and motor being of the same type each with one main shaft and provided with pistons reciprocating in cylinders

Abstract

A hydrostatic assembly employing a 1st hydraulic piston drive unit is described in which the output is increased without using additional servo assemblies by incorporating a 2nd hydraulic piston drive unit, coupling the drive shafts of both drive units together, and employing a common means to simultaneously adjust displacement of both the 1st and 2nd hydraulic piston drive units. In such embodiments, coupling the drive shafts together such that the 1st hydraulic piston drive unit is rotationally offset with respect to the 2nd hydraulic piston drive allows for a reduction in the amplitude of pressure pulsations associated with the hydrostatic assembly output, thereby smoothing out operation and improving durability.

IPC Classes  ?

• F16H 61/423 - Motor capacity control by fluid pressure control means
• F16H 61/433 - Pump capacity control by fluid pressure control means
• F16H 61/44 - Control of exclusively fluid gearing hydrostatic with more than one pump or motor unit in operation
• F16H 39/08 - Rotary fluid gearing using pumps and motors of the volumetric type, i.e. passing a predetermined volume of fluid per revolution with liquid motor and pump combined in one unit pump and motor being of the same type each with one main shaft and provided with pistons reciprocating in cylinders