Sauer-danfoss Inc.

Nick L Boone

Larry Walker

David D Dirks

Gary R Lingenfelter

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.

Torque limiting device for hydraulic piston pump

An extended male slipper servo pad provides an improved connection between the swashplate and a positioning mechanism in a variable displacement hydraulic unit. The swashplate assembly includes a swashplate having a socket formed therein and a male slipper servo pad pivotally attached to the swashplate at the socket. The male slipper servo pad has a ball end secured in the socket and a pad end having a substantially flat planar surface thereon directed away from the ball end.

Extended male slipper servo pad arrangement for positioning swashplate and method assembling same

A pump housing assembly includes a housing, a hub portion, and a flange. The housing has an end cowling defining a transition from a central portion of the housing to a transverse end portion. The hub portion extends longitudinally outwardly from the transverse end portion of housing. The flange extends radially outwardly from the outward end of the hub and is in spaced longitudinal relation to the end of the cowling to create a space to receive a head of a mounting bolt. The flange has an outer periphery with a pair of tangentially extending slots having an open end. The space for receiving a head of a mounting bolt is less than the length of a shank of a mounting bolt, to minimize the length of the housing. The slots have a width sufficient to receive the movement of a shank into and out of the open ends of the slots.

Pump housing mounting flange with tangentially positioned mounting slots

A lathe cut sealing ring includes a substantially cylindrical ring of elastomeric material formed about a central axis. The ring includes a rectangular cross-section and has an inner diameter, an outer diameter, opposite planar upper and lower surfaces, and a plurality of angularly spaced positioning ribs protruding inwardly from the inner diameter. This sealing ring and the groove in which it is located can advantageously be formed with simple and cost-effective lathe cutting operations.

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Ames, IA, United States of America

Nick L Boone