Caterpillar Inc.

Eric S Keyster

Dennis Henderson Gibson

Mark F Sommars

James R Blass

Bryan Edward Nelson

Jack Albert Merchant

Timur T Trubnikov

A variable delivery fixed displacement pump is provided which has a rotating drive plate with a fixed angle. The drive plate has a fill passage extending between its radial outer surface and its drive surface, which allows fluid to be supplied to a fluid journal bearing. The drive plate also has a series of bearing supply passages which fluidly connect the drive surface of the drive plate with a base surface, allowing fluid to be supplied to a fluid thrust bearing. A method of pumping fluid is also provided which is comprised of the steps of reciprocating a plurality of pistons at least in part by rotating the drive plate, and by fluidly connecting a pumping chamber of the pistons to an annular groove that is part of the drive plate fill passage.

Axial piston pump with outer diameter inlet filling

An axial piston pump with center inlet fill utilizes a hydrostatic thrust bearing and a hydrodynamic journal bearing to support a rotating wobble type drive plate connected to a drive shaft. The rotation of the drive plate causes a plurality of parallel pistons to reciprocate up and down. The pumping chambers of a portion of the pistons are fluidly connected via a center fill passage to the inlet defined by the pump housing. Simultaneously, the pumping chambers of a different portion of the pistons are fluidly connected to the outlet via a high pressure actuation fluid outlet passage. The center fill passage exploits centrifugal forces to assist, rather than resist, the supply of low pressure fluid to the pistons, especially when rotating at higher speeds.

Axial piston pump with center inlet fill

The present invention finds applicability in barrel assemblies defining a ring shaped cavity that is to be fluidly sealed from a central bore. Current barrel assemblies, such as those used in hydraulic pumps, are made from castings. This can be undesirable due to long production time and difficulty in producing consistent components. The present invention is directed to overcoming one or more of these problems by disclosing a barrel assembly and a method for making the same wherein the barrel and the plug are manufactured from the same material, or from materials having similar coefficients of thermal expansion. Thus, upon pump operation and optional heat treatment of the assembled barrel assembly, both the barrel and the plug will expand in a similar manner. The present invention finds application in axial piston pumps, especially for high pressure hydraulic systems, and other two piece components having a cavity requiring a seal.

Two piece barrel design for a hydraulic oil pump

A displacement pump includes a rotatable drive shaft; a low-pressure hydraulic fluid reservoir; at least one piston containing a piston cavity; and a drive plate connected with the drive shaft. The drive plate includes an inlet passage and a fill slot. The fill slot is fluidly connected with the low pressure hydraulic fluid reservoir via the inlet passage. The drive plate is rotatable about the drive shaft such that as the drive plate rotates, the piston cavity is intermittently fluidly connected with the fill slot.

Oil inlet for a wobble plate pump

A pumping system for supplying high pressure actuation fluid to individual fuel injectors of an engine equipped with a hydraulically-actuated fuel injection system wherein the three major elements of the system, namely, the pump, the rail pressure control valve and the bleed-off sump or reservoir are physically separated and spaced from one another. The pump is annular, having a central opening through which the engine crankshaft passes. The crankshaft and pump wobble plate are rotationally coupled by opposing flats on each. The pump, rail pressure control valve and reservoir are mounted directly to the engine, receiving and discharging fluid through internal engine passageways, thereby eliminating the usual tubing, and fittings. The pump itself is compact and relatively short in the axial direction, leaving space for mounting such things as a cylindrical housing having belt grooves in its outer surface and a viscous damper on the crankshaft between the pump and the terminal crankshaft end.

Pump apparatus for hydraulically powered fuel injection systems

A fuel injector adapter consists of a block defining a pressure communication passage therethrough and an actuation fluid passage. The actuation fluid passage includes three separate branches that open through an outer surface of the block at three separate locations.

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Peoria, IL, United States of America

Eric S Keyster