摘要:
An improved dual feed hydraulic lash adjuster (HLA), for use in an internal combustion engine, comprising a hollow body and a plunger assembly disposed in a bore of the engine. A one-piece plunger body includes a first chamber for forming a low-pressure oil reservoir and receiving a lash adjustment mechanism, and a second chamber open at one end and partially closed hemispherically for supporting a rocker arm and providing valve deactivating oil thereto for an auxiliary valve actuation system. The first and second chambers are separated by a transverse web, optionally having a small-diameter passage therethrough for air evacuation. The one-piece plunger body provides a high degree of resistance to side loads which may be imposed on the HLA in use.
摘要:
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.
摘要:
A two-step roller finger follower including an elongate body having side walls defining coaxially disposed shaft orifices, a pallet end and a socket end interconnecting with the side walls to define a slider arm aperture, and a latch channel. The socket end is mountable to an hydraulic 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 slider arm aperture and has a first end pivotably mounted to the pallet end of the body and the second end forming a slider tip for engaging an activation/deactivation latch. The latch is slidably disposed in the latch channel, and the latch has a nose section for selectively engaging the slider tip. A spool-shaped roller having first and second roller elements fixedly attached to the shaft is rotatably disposed in the shaft orifices, the roller being adapted to follow the surface motion of low-lift cam lobes. Preferably, the shaft is journalled in roller or needle bearings which extend between and through the first and second shaft orifices, being thus exposed to normal copious oil flow through the RFF.
摘要:
A two-step finger follower rocker arm assembly including a follower body having a socket at a first end for engaging a hydraulic lash adjuster and a pad at an opposite end for engaging a valve stem. A passage through the follower body in the direction of actuation by an engine cam is slidingly receivable of a slider member for variably engaging a central high-lift lobe. A lost-motion spring urges the slider member into contact with the central lobe. A latch member driven by a piston selectively locks the slider member to the follower body, causing the follower to follow the motion of the central cam lobe. When the latch member is disengaged, the slider member slides within the follower body, allowing lateral rollers to follow lateral cam lobes. The lateral rollers may be supported on the body by a rotatable cross-shaft or a fixed cross-shaft, or by a pair of fixed stub shafts, or by a pair of fixed bearing races.
摘要:
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.
摘要:
A roller finger follower rocker arm assembly for deactivating an engine valve. A follower body pivots on a hydraulic lash adjuster, and engages a valve stem or lifter. The body receives a reciprocating member having a first and second rollers outboard of the body for following eccentrics of a cam lobe that straddles the body, the body having elongate openings on either side of the reciprocating member. A locking pin selectively locks and unlocks the body to the reciprocating member. The reciprocating member does not make contact with the cam lobe and functions only as a link between the latching mechanism and the rollers. The pin engages the reciprocating member by a latching spring and is disengaged by pressurized oil supplied through the hydraulic lash adjuster. Means is provided for limiting axial growth of the HLA during deactivation mode of the rocker arm assembly.
摘要:
A two-step finger follower rocker arm assembly including a follower body having a socket at a first end for engaging a hydraulic lash adjuster and a pad at an opposite end for engaging a valve stem. A passage through the follower body in the direction of actuation by an engine cam lobe is slidingly receivable of a slider member for variably engaging a central cam lobe, preferably a high-lift lobe. An elongate shaft extends through a transverse bore in the slider member and through a slotted passage in the slider member. In the follower body, the shaft is provided with bearings supporting first and second lateral roller followers on opposite sides of the body for variably engaging first and second preferably low-lift lateral cam lobes flanking the central cam lobe. A lost-motion spring urges the slider member into contact with the central lobe. A latch member driven by a piston selectively locks the slider member to the follower body such that the follower follows the motion of the central cam lobe. When the latch member is disengaged from the slider member, the member slides within the follower body, allowing the lateral rollers to engage and follow the lateral cam lobes. Preferably, the latching mechanism is provided as a pre-assembled cartridge unit.
摘要:
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.
摘要:
A deactivating hydraulic lash adjuster comprising a pin housing slidably disposed in a body and having at least one lock pin disposed in a transverse bore for extending into a receiver feature in the body to lock the two together during periods of engine operation in valve non-deactivation mode. The present improvement consists in providing a first orienting feature for the lash adjuster body that engages a second orienting feature on an engine head to provide a preferred and fixed orientation of the body within a bore in the engine head. In a currently preferred orientation, the axis of the at least one lock pin is parallel to the axis of the engine camshaft. The orientation of the lock pin(s) to the body is made invariant by insertion of a pin through a radial bore in the body into a longitudinal groove in the pin housing.
摘要:
An internal combustion engine is equipped to supply the camshaft bearings with pressurized oil via a first dedicated oil gallery independently of the hydraulic lash adjusters (HLAs) and any valve deactivation devices which are supplied from a second dedicated oil gallery. The galleries may be connected at their downstream ends and a flow restriction is placed in a connecting passage or within each HLA. An improved HLA is similar to a prior art HLA except that the prior art annular oil distribution groove in the outer surface of the HLA body is eliminated to prevent communication of the primary engine oil gallery with the HLA. The secondary gallery is formed remotely from the first oil gallery in the HLA residence bore in the engine, and the HLA is prevented from rotating within the residence bore.