Caterpillar Inc.

Shin Caterpillar Mitsubishi Ltd.

Wayne W Lark

Denny E Morgan

James R Turba

David P Smith

Daniel T Mather

Hans P Dietz

Thomas G Skinner

David J McIntyre

James Frances Blubaugh

Sean P Wiltz

A metering valve for a work machine hydraulic system is disclosed. The metering valve has an inlet and an outlet, a main poppet, and a solenoid-operated pilot element. The main poppet is movable to pass fluid from the inlet to the outlet, and to block fluid from the inlet to the outlet. The solenoid-operated pilot element is movable between a first position at which pressurized fluid from the inlet pressurizes a control chamber in communication with a control end of the main poppet to urge the main poppet toward the flow-blocking position, and a second position at which the control chamber is communicated with a drain to move the main poppet toward the flow-passing position. The metering valve also has a relief valve element configured to drain pressurized fluid from the control chamber to move the main poppet toward the flow-passing position in response to a pressure at the inlet exceeding a predetermined pressure.

Metering valve with integral relief and makeup function

The present fluid cylinder includes a cylinder body having a cylindrical internal cavity therein with a longitudinal axis therethrough, the internal cavity being adapted for disposition of a piston and rod assembly for axial movement therein. The cylinder includes a member such as an end cap enclosing an axial end of the internal cavity, the member having a sensor port or passage therethrough extending between an internal opening communicating with the internal cavity and an external opening. A sensor is disposed in the internal opening of the sensor port or passage, and a sensor electronics module is disposed therein between the sensor and the external opening. The sensor is operable for sensing an axial distance of the piston or the rod from a predetermined location when disposed in the internal cavity and outputting signals representative of the distance to the sensor electronics module which includes circuitry for retrieving the signals.

Fluid cylinder with embedded positioning sensor

Improvement of the ability to detect selected resonant frequencies associated with the position of the piston in a piston position sensing system using electromagnetic waves in the fluid in a hydraulic cylinder is achieved by positioning the electric signal input and output probes with 90 degree separation around the circumferential periphery of the cylinder to suppress coupling into unwanted modes that diminish detectability of particular resonant frequency signals, In a coaxial sensing system 'dummy' probes at 90 degree separation to each other and 90 degree separation to the input and output probes operate to improve symmetry and resonance shape and to suppress unwanted modes.

Signal improvement in the sensing of hydraulic cylinder piston position

A coaxial capacitor contacting and sealing structure, for electrical continuity between parts that move in relation to each other at the ends of a cavity within a hydraulic cylinder employing electromagnetic wave position sensing. The structure employs a contacting and sealing member having a high surface conductivity that is mounted in one of the parts. The mounting of the contacting and sealing member provides force for pressure contact in oil between the parts and to enhance electrical continuity with the part in which the contacting and sealing member is located.

Hydraulic cylinder with an electrical contacting and sealing ring

A contacting and sealing structure, for electrical continuity, noise reduction and leakage reduction between parts that move in relation to each other at the ends of the cavity within a hydraulic cylinder employing electromagnetic wave position sensing, is provided by employing two springs having garter and canted coil spring functions that are retained in side by side grooves in one of the parts so that the spring coils extend directly across the intersection of the parts.

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Joliet, IL, United States of America

Wayne W Lark