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AssigneeINA-Schaeffler KG
InventorsHermann Wenisch, Mario Kuhl, Peter Sailer, Oliver Schnell
Estimating the term…
In a switching element (1) for a valve train of an internal combustion engine for switching to different valve lifts, said switching element (1) comprising an outer element (2) having an inner element (4) arranged for axial displacement therein, each of the outer and the inner element (2, 4) comprising a reception (11, 9) aligned to each other in a relative position, at least one piston (10) being arranged in at least one of the receptions (11, 9) for sliding toward the other of the receptions (9, 11) to couple the inner element (4) to the outer element (2) in said relative position, and a high-position stop for defining said relative position being arranged between the inner and the outer element (4, 2), at least one part of the high-position stop is configured as an adjustable, separate element (13). This element (13) cooperates through a preferably conical section (15) of its outer periphery with a complementary chamfer (18) on one end (17) of a guide (16) in the outer element (2). By these extremely simple fabrication measures, an aligned adjustment of the receptions (9, 11) is created for effecting coupling.
A switching element for a valve train of an internal combustion engine for switching to different valve lifts, said switching element comprising an outer element having an inner element arranged for axial displacement therein, each of the outer and the inner element comprising a reception aligned to each other in a relative position, at least one piston being arranged in at least one of the receptions for sliding toward the other of the receptions to couple the inner element to the outer element in said relative position, and a high-position stop for defining said relative position being arranged between the inner and the outer element, wherein at least one part of the high-position stop is configured as an adjustable, separate element, the adjustable, separate element is a piston-like element, a first section of whose outer periphery is fixed in a recess of one of the inner element and the outer element, and a second section of whose outer periphery engages a guide that is made as a slot in the other of the inner element and the outer element and has a length that is at least equal to a relative motion between the inner element and the outer element, one end of the guide forms a further part of the high-position stop, and at least that end of the piston-like element that is situated opposite said one end of the guide comprises a chamfer that bears against a complementary chamfer of the said one end of the guide in the relative position, said piston-like element being axially displaceable in the relative position for establishing an alignment of the receptions of the inner and the outer element.
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
By fluid means, e.g. hydraulically: hydraulic tappets
Tappets ; Push rods: push-rods
Modifications of valve-gear to facilitate reversing, braking, starting, changing compression ratio, or other specific operations: for optimising…
Manufacturing of components used in valve arrangements
Term ended 18 Sep 2022 (estimated)
The invention concerns a switching element for a valve train of an internal combustion engine for switching to different valve lifts, said switching element comprising an outer element having an inner element arranged for axial displacement therein, each of the outer and the inner element comprising a reception aligned to each other in a relative position, at least one piston being arranged in at least one of the receptions for sliding toward the other of the receptions to couple the inner element to the outer element in said relative position, and a high-position stop for defining said relative position being arranged between the inner and the outer element.
A switching element of the pre-cited type is disclosed in the generic prior art document DE 199 15 531 which shows a switchable cam follower for a tappet push rod drive. The high-position stop for defining the relative position is formed by a piston-like element arranged in the inner element. This piston-like element projects radially outward into a longitudinal groove of the outer element. In the axially extracted state of the inner element from the outer element, the piston-like element abuts against one end of the longitudinal groove. The purpose of this is to create an aligned arrangement of a coupling bore made in the outer element for a piston arranged in the inner element for achieving coupling.
A drawback of this prior art is that an adjustment of lash in the coupling is relatively complicated and cost-intensive. It is clear that the reception (coupling bore) in the outer element for receiving the piston must be configured with a slight lash relative to the outer peripheral surface of the piston. This lash and the high position differ from switching element to switching element due to fabrication conditions. The relatively wide range of variance of this mechanical idle travel in switching elements is, however, undesirable.
The sole FIGURE shows, in a longitudinal section, a switching element of the invention made in the present case as a roller tappet for a tappet push rod drive.
The FIGURE discloses a switching element 1 that is configured as a roller tappet. The switching element is designed for switching to different valve lifts, in the present case, for switching between a zero lift and a full lift. The switching element 1 comprises an outer element 2 in whose recess 3 an inner element 4 is received for axial displacement.
On one end, the switching element 1 comprises a roller 5 for contacting a cam and acts at the opposite end through a support 6 on a tappet push rod in lifting direction. In the present example, the support 6 is a part of a hydraulic lash adjuster 7.
A lost motion spring 8 that does not need to be described here, acts axially between the inner element 4 and the outer element 2. The inner element 4 comprises a radially extending cylindrical reception 9 in which a piston 10 for coupling the inner element 4 to the outer element 2 is received. The piston 10 is biased radially outward by the force of a compression spring 11a. In the relative position of the inner element 4 to the outer element 2 shown in the FIGURE, a reception 11 in the outer element 2 is situated opposite the piston 10. For coupling, the piston 10 can be displaced partially into the reception 11 by the force of the compression spring 11a.