Caterpillar Inc.

Christopher W Pruess

Jeremiah C Johnson

Paul Anthony Dvorak

Christopher Mark Elliott

John M Seipold

William Christopher Swick

Christopher J Demick

Aaron Benjamin Crabtree

Marek Golebiowski

Vincent Guyard

Disclosed is a system comprising a variator and a transmission. The transmission housing includes a mounting joint transmission face and one or more transmission ports disposed in the mounting joint transmission face that are fluidly connected in a one-to-one correspondence to one or more transmission channels in the transmission housing. The variator housing may comprise a mounting joint variator face coupled to the mounting joint transmission face and one or more variator ports disposed in the mounting joint variator face. The one or more variator ports may be fluidly connected in a one-to-one correspondence to one or more variator channels in the variator housing. The one or more variator ports are fluidly connected in a one-to-one correspondence to the one or more transmission ports without the use of one or more external hoses to fluidly connect the one or more variator ports to the one or more transmission ports.

Hydraulic connection

A system including a gearbox and a hydraulic machine connected by a working fluid circuit. The gearbox including a gearbox housing having first and second gearbox fluid passages integrated into the gearbox housing. The hydraulic machine including a case having first and second hydraulic machine fluid passages, the first and second hydraulic machine fluid passages being integrated into the case. A set of rotating elements enclosed within the case. The first gearbox fluid passage and the first hydraulic machine fluid passage align to form a feed passage to conduct fluid at a first pressure from a first source to the set of rotating elements. The second gearbox fluid passage and the second hydraulic machine fluid passage align to form a charge passage to conduct fluid at a second pressure from a second source to the set of rotating elements. The first pressure being less than the second pressure.

Cooling scheme for hydrostatic transmission

In a piston pump assembly, cradle bearings support a swash plate on an inner surface of a housing assembly. The cradle bearing and/or the corresponding portion of the housing inner surface may have undercut portions allowing deflection of an inward portion of the cradle bearing when the swash plate is subjected to pressure forces from hydraulic fluid compressed within pump cylinders by the pump pistons. Deflection of the cradle bearings allows increased contact pressure to be further distributed across the engaging surfaces of the swash plates and the cradle bearings.

Stress reduction in hydrostatic cradle bearing

A closed hydrostatic circuit with variable charge and variable flushing systems is disclosed. A variable displacement charge pump is configured to supply charge fluid and pilot control fluid to the hydrostatic circuit. An electronically controlled pressure regulating valve is in communication with an output of the charge pump and is linked to a controller. When the hydrostatic control system detects a high hydraulic temperature condition, the electronically controlled pressure regulating valve, that is in communication with an output of the charge pump and that is linked to a controller, increases the charge pump flow. A bidirectional variable displacement hydrostatic motor is connected in parallel to two input/output lines. A flush valve is in communication with the hydrostatic motor and both input/output lines. The flush valve and hydrostatic motor are both in communication with the flush orifice and a flush relief valve. When the pressure regulating valve causes the charge pump to operate at or near a full capacity, fluid exits the flush valve and passes through both the flush orifice and the flush relief valve. In contrast, when the pressure regulating valve causes the charge pump to operate at a lower or near minimum capacity, fluid exits the flush valve and passes through the flush orifice only without passing through the flush relief valve.

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Plainfield, IL, United States of America

Christopher W Pruess