Caterpillar Inc.

James C Goade

Claude H Werner

William K Engel

Michael H Haselkorn

Donald H Sherman

Phillip L Freeman

A flexible retention mechanism for maintaining a positional relationship between a bearing cage of an arcuate roller bearing assembly and a swashplate supported by the bearing assembly includes a flexible retainer connected to the bearing cage and having a pair of end portions resiliently engaging a pair of anchor pins extending outwardly from the swashplate.

Retention mechanism for a cage of a swashplate bearing

Transmitting actuating forces from an actuator to a swashplate of an axial piston unit through a pin extending from a lever of the swashplate induces torsional stresses in the lever. The present invention overcomes this problem by securing a lever to a swashplate so that a distal end portion thereof extends into a slot of an actuator. The distal end portion has a cylindrical shaped surface pivotally seated in a mating socket formed in a slide block positioned within the actuator slot. The actuating forces transmitted from the actuator to the lever are thus transmitted in a straight line motion with minimal torsional stresses introduced into the lever.

Swashplate actuating device for axial piston pumps and motors

Piston assemblies for use in fluid translating devices normally are made of hardened metal alloy materials which require very smooth surface and are always subject to varying degrees of thermal expansion when being operated at high operating temperatures. In the subject arrangement, a piston assembly is provided and is constructed of most, if not all, ceramic components. The piston assembly includes a ceramic piston having a spherical head portion at one end thereof which rests in a spherical cavity of a ceramic slipper and held therein by a cylindrical ring. The cylindrical ring can be of a one-piece or a two-piece design which is in contact with the spherical head portion and bonded to the ceramic slipper, thus, retaining the spherical head portion. The cylindrical ring could also be made of a metallic material. The metallic ring is bonded to the ceramic slipper and subsequently swaged to hold the spherical head portion within the spherical cavity. The subject ceramic piston assembly provides a very smooth surface which reduces sliding friction and likewise the effects of thermal expansion and inertia are minimized by the use of a ceramic material. Consequently, the subject piston assembly is very efficient when operating at high temperatures and, likewise, is easy to manufacture and assemble.

Piston assembly for a fluid translating device

Arcuate bearings are useful, for example, in pivotally supporting a cradle swashplate of axial piston variable displacement hydraulic devices. The bearings of known hydraulic devices have either been a pair of laterally spaced roller bearings assembly or a pair of laterally spaced sleeve bearings. The subject hydraulic device includes a roller bearing assembly positioned between the swashplate and the housing at the side of the swashplate subjected to high loads and a less expensive sleeve bearing positioned between the swashplate and the housing at the other side of the swashplate subjected to low loads. By using this combination of bearings, the overall cost of the hydraulic device is reduced without impairing the operation of the hydraulic device.

Cradle bearing arrangement for axial piston hydraulic devices

Reversible, variable displacement, hydraulic devices are useful in transmitting power from an engine to a driven device. The hydraulic components of such devices are generally quite bulky and difficulty to center to swash plate thereof. The subject device includes a pair of servo valves adjustably disposed within a case for individually controlling the flow of actuating fluid to and from a pair of hydraulic servo actuators. A servo feedback mechanism is provided to mechanically move a valve spool of one of the servo valves to a position for exhausting fluid from one of the servo actuators as the spool of the other servo valve is moved to a position for directing actuating fluid to the other of the servo actuators. The feedback mechanism also moves the spools substantially to their neutral position when a swash plate controlled by the servo actuators reaches a desired angular position after the other spool is first moved to the position for directing actuating fluid to the other servo actuator. The feedback mechanism is compact and cooperates with the adjustability of the servo valves so that centering of the swash plate is simplified.

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Morris, IL, United States of America

James C Goade