Delphi Technologies, Inc.

Andrew J Lipinski

Hermes A Fernandez

Nick J Hendriksma

Thomas Huntington Fischer

Timothy Wilton Kunz

Richard Blanco Roe

Albert C Stone

Carl Ralph Kangas

William Dean Bauman

Cynthia A Tawaf

Eric G Wilusz

Joseph C Gerzseny

A two-step roller finger follower assembly for use in conjunction with a camshaft of an internal combustion engine, wherein the camshaft has at least one first lobe and at least one second lobe. The roller finger follower assembly comprises a follower body for engaging the first cam lobe and having a central aperture, a follower pivotably disposed on the follower body in the central aperture for engaging the second cam lobe, and a limiting stop disposed on the follower body for engaging a feature on the follower to limit travel of the follower body with respect to the follower. The limiting stop prevents overtravel of the follower body during valve-deactivation mode of the assembly, thus preventing excessive leak down of an associated hydraulic lash adjuster.

Two-step roller finger cam follower assembly having a follower travel limiter

A two-step roller finger follower having a high-lift follower portion that pivots on a pivot shaft disposed on a low-lift follower portion, and having a lost-motion spring disposed between the high-lift follower and the low-lift follower to bias the high-lift follower toward the high lift cam lobe. Various bearing cups and roller shaft sleeve embodiments are shown, all of which allow for improved shaft and needle bearing arrangements. A z-stop formed by the bearing cups and/or the shaft sleeve limits the range of travel of the high-lift follower with respect to the low-lift follower. Various z-stop embodiments are provided including a non-contacting roller shaft sleeve that grounds the high-lift follower to the low-lift follower independent of the roller shaft.

Roller bearing and z-stop for a two-step roller finger follower

A two-step roller finger follower having a high-lift follower portion that rotates relative to a low-lift follower portion about a pivot shaft, including a lost-motion compression spring disposed in a linear bore formed in the high-lift portion to exert force against an curved pad on the back side of the valve pallet of the low-lift portion. The spring is retained and guided in its bore by a spring retainer having a planar bottom for engaging the curved pad. Preferably the retainer is a cup positioned in the spring bore such that the stroke of the cup is limited, to prevent leak-down of the associated hydraulic lash adjuster. Driving the spring by a linear-acting retainer in a linear bore causes the spring to be compressed linearly, resulting in a highly stable and predictable spring rate.

Two-step roller finger follower

A two-step roller finger follower having a movable high-lift portion and a low-lift portion. A lock pin mechanism in the low-lift portion includes a lock pin that may be driven hydraulically into latched engagement with the high-lift portion. The lock pin assembly comprises a lock pin and a separable switching pin. A blocking clip mountable on the associated hydraulic lash adjuster includes first and second ends that extend into a switching pin locking groove to block axial motion thereof. A ramp on the follower body mates with a ramp on the blocking clip such that oscillatory motion of the follower engages and disengages the blocking pin from the locking groove. The clip unblocks the switching pin at only those times in the camshaft rotational cycle when complete locking and unlocking is assured, and ending well before the beginning of the next valve lift event.

Timing mechanism for a switchable two-step roller finger follower

In a two-step roller finger cam follower, a slider arm for engaging a high-lift cam lobe is pivotally mounted to the body and can variably engage a latch pin slidably disposed in a latch pin channel. A second channel in the body opens onto the slider arm and contains a timing pin that rides on an eccentric surface of the slider arm to extend or retract the timing pin. A bore between the latch pin channel and the timing pin channel contains a ball controlled by the timing pin to lock the latch pin into an engaged or disengaged position. The cam lobe has an undercut region such that the latch pin is allowed to move between engaged and disengaged position only when the slider arm is in the undercut region of the cam lobe. The latch pin can move only when the timing pin permits.

Latch timing mechanism for a two-step roller finger cam follower

A two-step roller finger follower for shifting between high-lift and low-lift valve modes includes a body having side members defining coaxially disposed shaft orifices, a pallet end, a socket end, a slider arm aperture, and a latch pin channel. The socket end is mountable to a lash adjuster, and the pallet end is matable with a valve stem. A slider arm for engaging a high-lift cam lobe is disposed in the aperture, is pivotably mounted to the body, and includes a slider tip for engaging a latch pin having a nose section. A spool-shaped roller is adapted to follow the surface motion of low-lift cam lobes. The axis of the latch pin intersects a radius extension of the slider arm at an angle of less than 180&#xb0; such that the latch pin is prevented from accidentally locking the slider arm in its lost-motion position.

Two-step roller finger cam follower having angled lock pin

A two-step finger follower rocker arm assembly for cooperating with high-lift and low-lift cam lobes of an engine camshaft. The rocker arm assembly includes a follower body for engaging an hydraulic lash adjuster and a valve stem. A central well contains a roller for following the central low-lift cam lobe. Pivotably mounted on the body are lateral high-lift followers, including sliders or rollers, for following the lateral high-lift cam lobes. A latch block disposed on the body surface is slidable by piston and spring means between first and second positions to engage and thereby alternatively latch and unlatch the high-lift followers. In latched position, the rocker arm assembly acts in high-lift mode; in unlatched position, in low-lift mode.

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Henrietta, NY, United States of America

Andrew J Lipinski