摘要:
A tappet (1) for a valve operating mechanism for an internal combustion engine comprising a thin-walled jacket (3) guided in a bore (5) of a cylinder head (6) and provided in the cam direction with a circular ring-shaped bottom (4) which surrounds a circular bottom (16) of a concentrically arranged guide sleeve (7) in whose bore (9) a clearance compensation element (10) is arranged for longitudinal displacement, the jacket (3) comprising the circular ring-shaped bottom (4) and the guide sleeve (7) comprising the circular bottom (16) being engageable by cams of differing pitch and relatively displaceable axially with respect to each other and with respect to the bore (5) of the cylinder head (6), and a first, central cam (14) of smaller pitch and at least one cam (15) of larger pitch selectively engaging the circular bottom (16) and the circular ring-shaped bottom (4) respectively, characterized in that means are arranged in the jacket (3) which prevent an axial rotation of the tappet (1) in the bore (5) of the cylinder head (6) and at the same time also prevent an axial rotation of the guide sleeve (7) which is arranged concentrically in the tappet (1) and in whose bore the clearance compensation element (10) is mounted for longitudinal displacement, at least one axially acting pressure spring (22) being arranged between the circular ring-shaped bottom (4) and a radial flange (12) which projects from the guide sleeve (7) and is guided on an inner peripheral surface (13) of the jacket (3).
摘要:
A two-part tappet is designed to be adaptable to different cam contours. Radial bores (11, 12) are provided in the base sections (2, 3) for receiving at least one radially shiftable piston (13) for coupling the sections (2, 3).
摘要:
A tappet (1) for a valve drive of an internal combustion engine is so designed as to be switchable for different valve lifts and includes an outer circular ring shaped section (5) which encloses a circular section (6). Both sections (5, 6) are acted upon by cams of different lifts, and selectively interconnectable together by coupling elements (9). According to the invention, a juncture (12) for hydraulic fluid is positioned in the skirt (2) and extending from a feed bore (13) in the cylinder head (4) at a lowest point of the tappet (1), when viewed in direction of gravity, in order to install the tappet (1) in an extreme slanted disposition. In opposition thereto, a port (21) of the channel (27), following the juncture (12), is arranged at a highest section of the tappet (1), when viewed in the direction of gravity. Thus, after shut-down of the internal combustion engine, a reservoir (17) can empty only to the level of the port (21), so that the tappet (1) is sufficiently filled with hydraulic fluid when restarting the internal combustion engine.
摘要:
A switchable support element for a lever valve drive of an internal combustion engine comprising a hollow cylindrical housing arranged with an outer peripheral surface in a reception bore of a cylinder head, an inner element supported on the housing by a compression spring being arranged for axial displacement within the housing, while one front end of the housing or of the inner element bears at least indirectly against a finger lever and a second front end bears against he cylinder head.
摘要:
In a switchable cam follower (1) comprising an inner element (2) and an outer element (3), with said inner element (2) comprising a hydraulic clearance compensation device (10), a coupling of the two elements (2, 3) is effected by radially extending coupling means (4). These coupling means (4) and the clearance compensation device (10) which is integrated in the inner element (2) are loaded by hydraulic pressure from a cylinder head of an internal combustion engine through separate channels (9, 8). According to the invention, the spring means (5) for the coupling means (4) are configured so that from a hydraulic medium pressure from about 0.6 bars on (idling engine speed), the elements (2, 3) are uncoupled. When a switching engine speed, for example, 3,000 rpm, has been reached, the hydraulic pressure in the channel (9) is reduced to about 0.1 bars by a control valve (11). The coupling means (4) are displaced by the spring means (5) into a coupling position. The two elements (2, 3) are connected physically to each other. At the same time, unchoked hydraulic pressure continues to prevail in the channel (8) so that even with increasing speed of the internal combustion engine, the clearance compensation device (10) is optimally supplied with hydraulic pressure.
摘要:
A switchable cam follower (1) for a valve train (1b) of an internal combustion engine (1c) which is indirectly actuatable via tappet push rods (1a), the cam follower (1) comprising an outer section (2) which encloses an inner section (4) that is axially movable relative thereto, the outer section (2) having a pot-shaped configuration with a bottom (6) which comprises an end (5) for cam contact and separates the inner section (4) from a cam (4a) whereby upon coupling of the sections (2, 4) by a coupling means (23), a high lift of a gas exchange valve (22a) is effected, and upon uncoupling of the sections (2, 4), a zero lift, the cam follower (1) having a relatively simple structure with only a small design space requirement and can be installed in receptions (20a) of the internal combustion engine (1c) as provided hitherto for non-switchable cam followers.
摘要:
A tappet (1) is to be engageable on to at least three different cam profiles with an optional zero lift. To this end the tappet (1) consists of an annular base section (2) enclosing a circular base section (3). Both base sections (2, 3) can be coupled together via radially adjustable coupling devices (10). An additional, axially movable inner piston (18) is fitted in a guide sleeve (7) of the circular base section (3). The inner piston (18) can be decoupled via further coupling means (23) so that the tappet (1) can be completely decoupled from the guide sleeve (7).
摘要:
A tappet (1) is designed to be coupled for different lifts of at least one gas exchange valve. It comprises an outer annular section (2) which concentrically encloses a circular section (3). Both sections (2, 3) are axially movable relative to each other and are loaded in the region of their bottoms (4, 5) by cams of different lifts. Slides (8, 9, 13) extend in receptions (6a, 6b, 7) of the bottoms (4, 5). The first slide (8) cooperates with locking means (14) which scan a signal track on the opposing cam and, in a response to a lift of the signal track, block or permit a longitudinal movement of the first slide (8), the locking means yielding in their releasing direction under action of force. At the same time, the third slide (9) delimits on its radially outer end face (15), a pressure chamber for hydraulic medium. A displacement of all the slides (8, 9, 13) into their coupled position can be effected through this hydraulic medium. A particular advantage of the invention is that, on the one hand, the pressure chamber (16) for hydraulic medium is spatially separated from the locking means (14) so that no complicated sealing measures are required in the region of the locking means (14) because no hydraulic medium losses are to be expected. On the other hand, the locking means (14) are elastically mounted in cam-distal direction. They thus possess a certain yielding property for the event that due to the course of the signal track, the locking means (14) are prevented from taking their locking position on the first slide (8) by a section situated between locking recesses (24, 25) of the first slide (8).
摘要:
A cam follower (1) comprises an annular and a circular bottom portion (2, 3). The two bottom portions (2, 3) are concentric to each other, and a low lift cam (4) is arranged opposite the circular bottom portion (3) while at least one high lift cam (5) is arranged opposite the annular bottom portion (2). The cams (4, 5) are arranged out-of-phase with each other in circumferential direction. Since, therefore, when the cam follower (1) is coupled to the high lift cam (5), the low lift cam (4) would disadvantageously actuate the cam follower (1) with its excess lift, a means is provided in the cam follower for compensating this undesired lift.
摘要:
The invention proposes a variable valve train (1) for throttle-free load control of an internal combustion engine. Each cylinder of the internal combustion engine is provided with two inlet valves (9). According to the invention, each inlet valve (9) cooperates with a particular adjusting element (8, 8a), and the adjusting elements (8, 8a) can be actuated independently of each another. This additionally enhances the variability of the valve train.