Internal-combustion engines – Charge forming device – Fuel injection system
Patent
1995-06-29
1997-11-11
Miller, Carl S.
Internal-combustion engines
Charge forming device
Fuel injection system
123495, F02M 4100
Patent
active
056852746
DESCRIPTION:
BRIEF SUMMARY
STATE OF THE ART
The invention is directed to a fuel-injection pump as set forth hereinafter.
In a known fuel-injection pump of this so-called distributor type with radial pistons (EP 0,244,340 B1 or EP 0,303,237 A2), the distributor shaft carries, in the region of the radial bores receiving the pump pistons, a shaft portion of substantially larger diameter, in which radial indentations are made in line with the radial bores receiving the radial pistons, in which indentations the roller shoes together with the rollers or cylinders rotatably held therein are inserted displaceably. The coupling of the distributor shaft and drive shaft takes place via pairs of claws which project on the end faces of the distributor shaft and drive shaft and which engage without play in one another.
This constructive design necessitates a high manufacturing outlay for producing the distributor shaft and the cam mechanism, thus resulting in high manufacturing costs.
ADVANTAGES OF THE INVENTION
An advantage of the fuel-injection pump is that, by shifting the roller shoes together with the rollers into the drive shaft rotating synchronously with the distributor shaft, the distributor shaft can be produced substantially more simply as a lathe-turned part, and that, by inserting the roller shoes together with the rollers into simple axial slots in the hollow-cylindrical drive-shaft coupling head engaging over the distributor shaft on its end face, the drive shaft too can be manufactured cost-effectively; for in contrast to recesses or indentations to be countersunk radially in solid bodies of revolution, axial passage slots can be produced in hollow-cylindrical bodies of revolution very much more simply and cost-effectively in manufacturing terms.
Advantageous developments and improvements of the fuel-injection pump specified in herein are possible as a result of the measures listed hereinafter.
In a preferred embodiment of the invention, the rotationally fixed coupling between the drive shaft and distributor shaft is brought about by a coupling disk which is seated in the axial slots in the coupling head by means of coupling webs projecting radially on the disk circumference and preferably in one piece with said disk and which positively receives in a central recess a projection on the end face of the distributor shaft.
For a positive connection between the radial coupling webs of the coupling disk and the axial slots in the coupling head on the one hand, and between the central recess of the coupling disk and a projection on the distributor shaft, on the other hand, is such that there is a cardanic connection between the drive shaft and distributor shaft, with the result that tolerance-related offsets between the drive shaft and distributor shaft are compensated without difficulty.
If there are altogether four axial slots in the coupling head, which are in each case arranged offset at 90.degree. to one another, and, correspondingly, four radial coupling webs on the coupling disk which are arranged offset at 90.degree. to one another, such a cardanic articulation of the distributor shaft on the drive shaft is achieved, according to an expedient embodiment of the invention, in that two coupling webs arranged diametrically to one another are seated in the associated axial slots without play in the circumferential direction and the recess in the coupling disk has two flanks which extend parallel and at right angles to the coupling webs seated without play in the axial slots and against which the projection on the distributor shaft bears without play by means of parallel spigot surfaces facing away from one another.
According to a further embodiment of the invention, the two remaining coupling webs of the coupling disk which are located diametrically opposite one another are seated with play in the circumferential direction in the associated axial slots in the coupling head. The circumferential play is appropriately adapted to tolerances (center offset) occurring.
According to an advantageous embodiment of the invention, the coupl
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patent: 4167926 (1979-09-01), Leblanc
patent: 4362141 (1982-12-01), Mowbray
patent: 4462370 (1984-07-01), Jarrett
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patent: 5138997 (1992-08-01), Fehlmann
patent: 5462029 (1995-10-01), Nicol
patent: 5546906 (1996-08-01), Cooke
Fehlmann Wolfgang
Helmbrecht Peter
Junger Dieter
Kebrich Bodo
Morel-Fourrier J. Paul
Greigg Edwin E.
Greigg Ronald E.
Miller Carl S.
Robert & Bosch GmbH
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