Sauer-Danfoss Inc.

Sauer Gmbh

Deere & Company

David D Dirks

Wilhelm G&ouml;llner

Doug Kardell

James D Ryken

Jeffrey A Baldus

Douglas Rene Johnson

Trent Lynn Goodnight

Robert J Stoppek

Kerry G Geringer

Robert Klinkel

Nick L Boone

Scott D Meyer

Jim D Ryken

Larry Walker

A method of making a cylinder block for a rotatable hydrostatic power member by separating the cylinder block into its four geometries and joining them together. The geometries include a base plate having a center opening and a arcuate kidney-shaped openings uniformly spaced radially around the center opening. The second geometrical item is a grooved drive shaft that fits into the center opening of the base plate. The third member is a group of tubular bore elements that fit in the base plate and mate with the drive shaft. The final member is a torque ring that matingly fits over the tubular piston bore elements.

Hydrostatic cylinder block and method of making the 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

The output speed of a hydrostatic unit in a transmission is determined using a pair of variable reluctance sensors, one on a gear driven by the hydrostatic unit output and the other on the carrier of the planetary system. One of the two sensors will always be measuring a relatively high speed from which the hydro output is directly determined or indirectly determined using the current engine speed. Thus the frequency of the speed sensor used to determine the hydrostatic unit output speed is not decreased at slow hydrostatic unit output speeds.

Apparatus and method for determining the output speed of a hydrostatic unit in a hydro-mechanical transmission

A variable displacement bent axis hydraulic unit includes a control mechanism having a control housing with a displacement feedback sleeve and spool connected by a spring. A computer controls a proportional solenoid fluid valve that is in operative fluid engagement with the end of the spool opposite its spring connection with the displacement feedback sleeve. The displacement feedback sleeve is urged by the spring into engagement with a cam member on the yoke of the bent axis unit.

Single-piece proportional control

A special ball joint for servo piston actuation in a bent axis unit includes an elongated actuator rod having a substantially spherical external surface on a first end and a servo piston on a second end. Also included is a single-piece yoke adapted to carry a cylinder block and rotate about an axis of rotation. A socket having a substantially spherical surface is interposed between the yoke and the spherical surface on the rod such that the actuator rod rotates the yoke with forces residing in at least two planes when hydraulic pressure is applied to the servo piston. Two servo pistons and two such ball joints can be applied to the yoke to obtain rotation of the yoke which is up to greater than plus or minus 45&deg; from a neutral position. The external surface on the first end of the actuator rod and the socket must be mating so as to provide freedom of movement. The socket can be incorporated into the yoke itself. The foregoing servo pistons are received in servo bores of a one-piece control housing. An integral cam is formed in a control trunnion to accommodate the swinging movement of the yoke.

Ball joint for servo piston actuation in a bent axis hydraulic unit

A pump system includes a variable fluid displacement pump having a pressure line which is connected to a pressure load and connected to a load sensing control. A variable orifice is located downstream from the load sensing control. The variable orifice is fluidly connected to the load sensing control in a servo pressure conduit such that the margin pressure varies proportionally with respect to the fluid displacement Of the pump. The variable orifice can take many different forms, including a variable cross sectional area gap between the housing and an elongated servo piston longitudinally slidable therein. A longitudinal slot having uniformly increasing depth along the length of the servo piston gives the servo piston a cross sectional area which varies along its length. Thus, a variable orifice results.

Means and method for varying margin pressure as a function of pump

An improved apparatus for retaining slipper holddown pins radially in a hydraulic unit includes a cylinder block having a plurality of holes therein for respectively receiving a corresponding plurality of elongated slipper holddown pins, each having a maximum transverse width. The holes are adjacent to and communicate with a center bore of the cylinder block to form respective throats. The throats have a maximum width that is less than the maximum transverse width of the pins such that the pins cannot be radially displaced through the respective throats. Each hole has a side wall that extends more than 180.degree. around its central axis. The side wall defines the throat between the hole and the center bore. The shaft can be inserted into driving engagement with the center bore of the cylinder block. The slipper holddown pin has a maximum transverse width greater than the maximum width of the throat. Thus, the pin is radially constrained in the hole without applying external forces and cannot move radially outwardly through the throat. The bore of the cylinder block and the holes for receiving the pins can be simultaneously formed with a single broaching bar.

Growing community of inventors

Ames, IA, United States of America

David D Dirks