Caterpillar Inc.

David C Hale

John C Endsley

Frank J Raab

A method is provided for attenuating noise in a hydraulic circuit having a pump in fluid communication with a hydraulic actuator by a conduit. The method includes supplying a flow restricting device in the conduit and generating a signal representative of a fluid fluctuation in the conduit downstream of the flow restricting device. A bypass loop is provided in parallel with the flow restricting device and the bypass has a valve. The valve is controlled based on the generated signal to generate a corrective fluid flow to attenuate the noise.

Noise attenuation in a hydraulic circuit

A hydraulic pressure transformer for the conversion of an input hydraulic power to an output hydraulic power has a cam block. The cam block has a cam opening defining a pump section and a motor section. The pump section includes at least one pump inlet port and at least one pump outlet port. The motor section includes at least one motor inlet port and at least one motor outlet port. A rotor is disposed within the cam opening and is rotatable about an axis of rotation. The rotor includes a peripheral surface, a plurality of radially extending slots opening at the peripheral surface and a plurality of vanes respectively disposed in the slots. The rotor and/or cam block are movable relative to each other in at least one direction generally perpendicular to the axis of rotation.

Hydraulic pressure transformer

A hydraulic pressure transformer has a port block which is attached to an end cap. The end cap includes a plurality of ports opening at an end face and at least one actuation port opening at or near a peripheral surface. A barrel which is rotatable about an axis includes a second end face and a plurality of cylinders having respective cylinder ports which open at the second end face. A port block disposed between the first end face and the second end face is rotatable about an axis and has a first face surface, a second face surface and a plurality of ports extending between the first face surface and the second face surface. The port block includes a radial periphery and at least one vane extending radially outward from the radial periphery to a position adjacent the peripheral surface of the opening.

A hydraulic pressure transformer for the conversion of an input hydraulic power to an output hydraulic power includes a housing with a generally planar face surface and a plurality of ports opening at the face surface. A barrel which is rotatable about an axis includes a generally spherical end face and a plurality of cylinders opening at the end face. A port block interposed between the barrel and the housing is rotatable about the axis. The port block has a first face surface, a second face surface and a plurality of ports extending between the first face surface and the second face surface. The ports selectively fluidly interconnect the plurality of cylinders in the barrel with the plurality of ports in the housing. The first face surface is generally spherical and abuts the end face of the barrel. The second face surface is generally planar and abuts the face surface of the housing.

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Chillicothe, IL, United States of America

David C Hale