Internal-combustion engines – Poppet valve operating mechanism – Lubrication
Patent
1997-08-29
1998-10-20
Lo, Weilun
Internal-combustion engines
Poppet valve operating mechanism
Lubrication
123 9036, 123 9042, 123508, 123196M, 184 65, F01M 910, F01L 118
Patent
active
058231544
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on an internal combustion engine having a cam drive.
In one such engine, known from German Published, Non-Examined Patent Application DE-OS 38 26 144 A1, each cylinder of the engine to be supplied is assigned a separate fuel injection device. This device is controlled via a cam drive, which has a lever arm pivotable about a fixed bearing point. A roller that rolls on a cam path of a cam shaft precedes this rocker arm and transmits raising and lowering motions to a drive part that is operatively connected to the fuel injection device.
Such an arrangement, however, has the disadvantage that both the rocker arm and the roller rotatably supported in the rocker arm have no bearing lubrication, and thus because of the high forces to be transmitted there is major wear between the parts that are rotationally movable with respect to one another, which can cause inoperativeness or even seizing.
To enable lubricating such bearing locations, it is also already known from the general prior art that in stationary bearings, a direct delivery of lubricants to such bearings is made possible.
In bearings of components that move along a curved path, such as the roller in the rocker arm, it is often only very complicated or even impossible to deliver lubricants because of the reciprocating motion, so that these parts, because of their high wear, have a short service life.
ADVANTAGES OF THE INVENTION
The internal combustion engine according to the invention has the advantage over the prior art that a roller supported in the rocker arm can be supplied with lubricant, through a lubricant nozzle disposed in the region of a curved path of the roller, via a bore disposed in the roller bolt. As a result, at least at the moment when the roller bolt supported in the rocker arm passes over a lubricant supply point, lubricant can be picked up. The lubricant is advantageously sprayed in the direction of the bearing location, so that lubricant particles can enter the bore and thus get between the roller and the roller bolt for lubrication purposes. At the same time, this kind of lubricant delivery can contribute to lubrication of the roller bolt for the rocker arm, in the case of a rotatably supported roller bolt.
In an advantageous feature of the invention, where a roller bolt is supported on a rocker arm in a manner fixed against relative rotation, it is provided that the radially extending transverse bore is disposed pointing away from the cam path, so that lubricant can be delivered with certainty to the bearing location.
In another advantageous feature of the invention, it is provided that in the case of a rotatably supported roller bolt, at least one transverse bore is provided that completely penetrates the roller bolt. As a result, it can be assured that when the roller bolt is rotating as well that adequate lubrication can exist between the roller bolt and the roller.
In another advantageous feature of the invention, it is provided that the bore oriented toward the lubricant delivery device has a funnel-shaped opening. As a result, upon overtaking by the lubricant delivery device, a greater amount of lubricant can be received and supplied.
In another advantageous feature of the invention it is provided that the lubricant delivery device can be disposed in a region in which the roller passes through a bottom dead center position of the cam. This is the position having the least bearing load between the roller and the roller path, so that the supplied lubricant can have a better distribution between the roller and the roller bolt.
The lubricant delivery according to the invention to a cam drive may be used in fuel injection systems or for the drive of gas exchange valves of the internal combustion engine.
BRIEF DESCRIPTION OF THE DRAWING
Exemplary embodiments of the invention are shown in the drawing and described in further detail in the ensuing description. FIG. 1 is a schematic side view of a cam drive according to the invention of an internal combustion engine; FIG. 2 is a schematic secti
REFERENCES:
patent: 5127374 (1992-07-01), Morel, Jr. et al.
patent: 5394842 (1995-03-01), Kobayashi
patent: 5566652 (1996-10-01), Deppe
patent: 5588413 (1996-12-01), Stone et al.
Kirschner Juergen
Kuhn Uwe
Soccol Sandro
Greigg Edwin E.
Greigg Ronald E.
Lo Weilun
Robert & Bosch GmbH
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