Abstract:
A valve tappet actuated by a cam of an internal combustion engine comprises a cup (1) having a hollow cylindrical skirt (2) and a cup bottom (3) which closes the skirt (2) at one end. On an outer surface, the skirt (2) comprises a peripheral groove (4), and on an inner surface, at least one bead (5). Concentrically arranged within the cup (1) is an inner element (6) whose casing (9) bears against the bead (5, 21). A hydraulic valve clearance compensation element (10) is guided for axial displacement in the inner element (6). To simplify the manufacturing of this valve tappet, it is proposed that the cup (1) is hardened in a heat treatment process, and the inner element (5) is unhardened.
Abstract:
A valve drive of an internal combustion engine, includes a switching mechanism incorporated in a support element for support of a cam follower disposed in driving relationship between a camshaft and the gas exchange valve for switching a gas exchange valve to different valve lift curves in response to an operation of a cam arrangement, whereby the switching mechanism has a hollow cylindrical housing defining an axis and received within an enveloping outer casing, an inner element axially displaceable relative to the housing and so received within the housing as to form at their interface an annular gap, and a coupling mechanism movable in a radial direction in a first radial bore arrangement so as to couple the inner element with the housing in a base circle phase of the cam arrangement by bridging the annular gap to thereby maintain a contact of the cam follower upon the cam arrangement, and movable in a radial direction in a second bore arrangement which is spaced from the first radial bore arrangement in direction of the axis so as to effect a disengagement of the cam follower from the cam arrangement in a phase of maximum cam lift.
Abstract:
The clearance compensation element (1) of the invention which can be installed, for example, in a valve drive of an internal combustion engine has a certain idle stroke function for undesired overpressure states of its high pressure chamber (12) during a base circle phase of the actuating cam. According to the invention, a valve means (14) such as a ball which closes the high pressure chamber (12) in the direction of a reservoir (10) is freely movable within certain limits. The ball (14), while being extremely light, closes the valve seat bore (13) with the shortest possible stroke immediately upon commencement of the opening ramp (A.sub.N) of the cam.
Abstract:
A tappet (1) for a valve drive or an internal combustion engine comprising a hollow cylindrical housing (2) guided for axial displacement by a jacket (3) thereof in a reception bore (4) of a cylinder head (5), an end of the housing (2) facing a cam (8) being closed by a bottom (7), a guide sleeve (11) arranged concentrically in the tappet (1) for guiding a hydraulic clearance compensation element (10) being supported by a connected web (12) against the jacket (3) which is made of two separate, bush-like sections (14,15) of approximately equal diameter separated from each other in the region of a central transverse plane, and a first cup-shaped section (14) of the jacket (3) being connected at a cam-proximate end thereof to the bottom (7), characterized in that the second, lower section (15) comprises an extension (16) starting axially adjacent the first section (14) and extending into an immediate vicinity of the bottom (7), the second section (15) with its extension (16) has a smaller wall thickness than the first section (14) and is made as a sheet metal or plastic element, the extension (16) bears by an outer peripheral surface (17) thereof against an inner peripheral surface (18) of the first section (14).
Abstract:
A method of leakproof first filling of a hydraulic valve actuating tappet (1) with hydraulic oil,a) comprising almost completely filling the central oil reservoir (7) together with a high pressure chamber (18) situated axially between the bottom (11) of the pressure piston (10) and the guide sleeve (5), and the annular oil reservoir (17), with hydraulic oil, andb) filling at least the supply bore (19) leading to the annular oil reservoir (17), with a lubricating grease or a pasty material (20) which is flow-resistant at ambient temperature.
Abstract:
A tappet (1) for a valve drive of an internal combustion engine, characterized in that an upper edge (22) of the cylindrical element (15) extends directly along the underside (8) of the housing bottom (7) except in a region of a trough-like formation (24) provided in the cylindrical element (15) in a region of the underside (8) of the housing bottom (7) for oil transfer from the canal (19) into the annular oil reservoir (18), the ratio of the width of the recess (24) at an upper edge thereof facing the bottom of the width of the canal (19) is .gtoreq.1.75.
Abstract:
A tappet (2) has a hydraulic clearance compensating element (8) composed of a high pressure chamber (18), a housing (3) with a spring-loaded, longitudinally movable compensating piston (15) and a free piston (11) with a smaller diameter than the compensating piston (15). In order to obtain by simple manufacturing means a reduced elasticity in valve operation during the base circle phase of a cam (6), the ratio between the projected surface (20) of the compensating piston (15) that faces the high pressure chamber (18) and the projected surface (19) of the free piston (11) that faces the high pressure chamber (18) is higher than 3.
Abstract:
The novel mechanical valve tappet of the invention arranged in a guide bore of a cylinder head of an internal combustion engine is comprised of a cup-shaped housing with a hollow cylindrical wall (1) closed at one end by a bottom (2) which is contacted exteriorly by a control cam while a first flat end face of an adjusting element (7) bears against an inner surface of the bottom (2), a second flat end face of the adjusting element (7) which is parallel to the said first flat end face is in contact with an end of a valve stem of an engine valve, and the adjusting element (7) has a cylindrical peripheral surface and is retained by force engagement in a bore (6) of a hub (3) fixed to the said inner surface of the bottom (2), characterized in that an element (9, 11, 15, 16, 20, 21, 22, 26) which is resiliently biased with respect to the adjusting element (7) and the hub (3) is arranged between the hub (3) and the adjusting element (7).
Abstract:
In an assembly for simultaneously actuating two valves (2) of an internal combustion engine, comprising a beam-shaped bridge (6) in end regions whereof hydraulic lash adjusters (5) are lodged which engage stem ends of valves (2), the bridge (6) being guided parallel to longitudinal axes of the valves (2) in the cylinder heade (1), and valve actuating components engaging a central region of the bridge (6) between the two lash adjusters (5), a less complicated structure as compared to known constructions and thus also less design space requirement with, at the same time, reduced friction, are obtained by the fact that a rotatably mounted roller (8) adapted to be engaged directly by a control cam (10) is arranged at the center of the bridge (6).
Abstract:
A tensioning device for belts, chains and the like, particularly for toothed belts in the valve drive of internal combustion engines, the device comprising a support which can be fixed on the engine block and on which, firstly a lever carrying a pressure-contact roller is pivotably mounted, secondly, a tensioning element is arranged which presses against the lever via a piston and thirdly, a stop member is arranged which is displaceable parallel to its longitudinal axis from a mounting position into an operating position and in the mounting position blocks the stroke of the piston in an intermediate position by a stop surface and allows a free travel of the piston in the operating position, characterized in that the stop surface is formed by a lateral surface of the stop member which is parallel to the longitudinal axis of the stop member.