Gm Global Technolgoy Operations, Inc.

Stephen H Miller

Michael J Grimmer

Mark A Gehringer

Eric J Defenderfer

Charles E Jensen

Marcel R Cannon

Paul A Piorkowski

Steven P Balgaard

Robert J Gollehur

John T Freiwald

Stephanie A Erntser

Stephanie A Ernster

Anthony J Brower

A two-stage stiffness driveshaft includes a hollow cylinder having first and second ends and a hollow cylinder stiffness. An inner shaft having first and second ends and an inner shaft stiffness extends through the hollow cylinder. The inner shaft's first end and the hollow cylinder's first end are engaged via a rotational clearance fit. The inner shaft's second end is rotationally fixed to the hollow cylinder's second end to permit the inner shaft's first end to twist through a predetermined angle relative to the inner shaft's second end. The inner shaft's stiffness defines the driveshaft's first-stage stiffness, while the combined stiffness of the inner shaft and the hollow cylinder defines the driveshaft's second-stage stiffness. A damping element positioned between the inner shaft and the hollow cylinder controls variation in torque transmitted by the driveshaft and generates gradual transition between the first-stage stiffness and the second-stage stiffness.

Driveshaft with two-stage stiffness

A two-stage stiffness driveshaft includes a hollow cylinder defined by a longitudinal axis, a first end, a distal second end, and a hollow cylinder stiffness. The driveshaft also includes an inner shaft extending through the hollow cylinder along the longitudinal axis and defined by a first end, a distal second end, and an inner shaft stiffness. The first end of the inner shaft is engaged with the first end of the hollow cylinder via a rotational clearance fit. The second end of the inner shaft is rotationally fixed to the second end of the hollow cylinder such that the first end of the inner shaft can twist to a predetermined angle with respect to the second end of the inner shaft. The inner shaft stiffness defines a first-stage stiffness of the driveshaft, and the inner shaft stiffness and the hollow cylinder stiffness together define a second-stage stiffness of the driveshaft.

The invention concerns a vehicle body panel. The vehicle body panel, such as a floor pan, may have a generally planar portion adapted to be located adjacent to and conceal a vehicle component, such as a fuel pump module. An access portion is located within and extends out of plane of the generally planar portion, and includes a periphery, wherein the access portion is integral with the generally planar portion. Also, a cutting guide feature extends around it adjacent to the periphery.

Vehicle body panel access feature

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South Lyon, MI, United States of America

Stephen H Miller