Patent ID: 8001940
Filing Date: 2011-08-23
Classification: F01L

Abstract:
1. A switchable bucket tappet for a valve drive of an internal combustion engine, comprising: a bucket basic body having a ring-shaped base being guided by means of a skirt projecting from an outer edge of the ring-shaped base in a bore of the internal combustion engine, the ring-shaped base being acted on by at least one lifting cam with a hollow cylindrical extension projecting from an inner edge of the ring-shaped base, in a bore of the hollow cylindrical extension runs an inner body which is axially movable relative to the bucket basic body and which has underside with an abutment for at least indirect contact with a gas exchange valve, and at least one coupling piston running in a bore of the inner body, the coupling piston, in order to obtain a full valve lift, being placed in engagement in sections with a driver surface of the bucket basic body, and with a lost motion spring acting between the bucket basic body and the inner body, wherein a zero valve lift is obtained when the coupling piston is moved completely into the bore of the inner body, the inner body being formed without a base so as to be entirely free from contact with the cam, the coupling piston having a flattened portion on an upper side proceeding from a radially outer face, the flattened portion and the coupling piston, in a coupled state, being moved under a flat counterpart surface of the hollow cylindrical extension as a driver surface, the flat counterpart surface being situated axially below a region of the ring-shaped base of the bucket basic body, the region of the ring-shaped base being of virtually symmetrical and entirely thin-walled design, and the inner body being freely rotatably movable with respect to the bucket basic body, and wherein the inner body is of substantially hollow cylindrical design, with an annular web, in which each coupling piston is arranged, running at a distance from end surfaces of the inner body.