Internal-combustion engines – Poppet valve operating mechanism – Tappet
Reexamination Certificate
2000-01-03
2001-02-27
Lo, Wellun (Department: 3748)
Internal-combustion engines
Poppet valve operating mechanism
Tappet
C123S090480, C123S090500
Reexamination Certificate
active
06192846
ABSTRACT:
FIELD OF THE INVENTION
The invention concerns a housing for a switchable cup tappet of an internal combustion engine, said housing being made as a one-piece component and comprising a sleeve-shaped inner guide having a bore for receiving an inner element which is contacted by a first, separate cam, said housing also comprising a cylindrical bottom portion for making contact with at least one second, separate cam, and a circular cylindrical jacket coaxially surrounding the inner guide, said inner guide comprising openings for receiving locking pins which extend at right angles to the housing axis.
BACKGROUND OF THE INVENTION
A switchable cup tappet, also called a switching cup, is a device for adjusting or compensating valve lash in an internal combustion engine and can be switched to at least two different operational states for establishing different valve openings. In standard switching cups, the housing fulfils the function of transmitting the standard cam lift through the cylindrical bottom portion to the engine valve. Such tappet housings have to be secured against rotation.
In a switchable cup tappet known from DE-OS 43 14 619, a concentric reception bore is arranged at the center of the housing for receiving lift and force transmitting means which constitute the inner element and at the same time effect lash adjustment. In the case of this inner element, an inner housing arranged for axial displacement in the reception bore and an additional, separate cam permit the execution of a cam lift different from and, as a rule, smaller than the standard lift.
The inner element, or inner housing, can be displaced into and locked in different positions relative to the bottom. In a locked state, a higher lift is effected due to the action of the larger cam on the bottom portion. In the unlocked state, the smaller cam, which then acts directly on the inner element that is arranged for sliding in the reception bore, creates the lower lift of valve actuation.
In known switching cup housings, so-called eyes for the reception bores of the locking mechanism are made in one piece with the bottom and the inner guide. On the one hand, this increases the weight of the housing and, on the other hand, it necessitates complicated work procedures.
SUMMARY OF THE INVENTION
The object of the invention is to create a light-weight housing which by joining with separate connection pieces forms a simple-to-manufacture base body for a switching cup.
The invention achieves this object by the fact that the housing is configured as a thin, drawn sheet metal part whose jacket likewise comprises openings which are aligned to the openings of the inner guide.
For the low lift inner element to be arranged in the bore and for preventing a rotation of the inner element relative to the cup housing, a contact surface can be formed in the inner guide to extend into the bore. A simple-to-implement contact surface is made in the form of a flat surface.
REFERENCES:
patent: 5431133 (1995-07-01), Spath et al.
patent: 5782216 (1998-07-01), Haas et al.
patent: 5832884 (1998-11-01), Haas et al.
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patent: 3820645 (1989-12-01), None
patent: 4314619 (1994-11-01), None
patent: 2158991 (1973-05-01), None
patent: WO 95/30081 (1995-11-01), None
Bierman, Muserlian and Lucas
Ina Walzlager Schaeffler OHG
Lo Wellun
LandOfFree
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