Fluid sprinkling – spraying – and diffusing – Unitary injection nozzle and pump or accumulator plunger
Reexamination Certificate
1999-12-17
2001-01-09
Kashnikow, Andres (Department: 3752)
Fluid sprinkling, spraying, and diffusing
Unitary injection nozzle and pump or accumulator plunger
C239S090000, C239S093000, C239S096000, C239S124000, C239S533700, C239S533120
Reexamination Certificate
active
06170757
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to a fuel injection valve for internal combustion engines.
One such valve member is disclosed by German Patent Application DE 197 33 905, which was not published by the filing date of the present application. Such a fuel injection valve for internal combustion engines has a valve member which emerges on the outside from the valve body and on which at least two rows of injection ports, located axially one above the other, are provided. The injection parts can be opened in succession in the outward-oriented opening stroke of the valve member. The injection parts have a two-stage hydraulic stroke stop that limits the opening stroke angle of the valve member and is embodied as a hydraulic damping chamber with a relief line that can be opened. The relief line is effected via at least two ground faces on the valve member which can be opened one after the other during the opening stroke motion of the valve member. One of the ground faces can be made to communicate with a low-pressure chamber via a relief conduit that contains a valve. The damping chamber is provided in a shim fastened between the valve body and a valve retaining body and is defined on an axial end opposite the end face of the valve body by a piston, secured to the valve member. The piston is guided by its outer circumference sealingly and slidingly displaceably along the wall of the damping chamber.
The piston is embodied as a plastic, U-shaped sealing ring open toward the damping chamber and pressed onto the shaft of the valve member. A spring is placed in the U-shaped sealing ring. A problem here is that the sealing ring suffers very great wear. Embodying the sealing ring as a metal is problematic because of its vulnerability in terms of tolerances.
OBJECT AND SUMMARY OF THE INVENTION
An object of the invention is to further develop a fuel injection valve of this type such that under the existing load conditions in an internal combustion engine, the fuel injection valve largely assures a constant function over its entire life. In particular, the risk of high abrasion at very short strokes at a high relative speed, the influence of production variations that occur in guides disposed close to one another in line, and pulsating impact stress on the fastening of the piston and on the valve member that result from the load pressure should be eliminated.
In a fuel injection valve of the type described at the outset, this object is attained by the characteristics set forth hereinafter.
The piston is embodied as a multi-part structure, including the piston element with a bearing face that rests on a curved contact face embodied on the valve member, and includes the retaining element for fixing the piston element to the valve member. In one version of the invention, the retaining element is connected via an elastic element disposed between the piston element and the retaining element. In another version of the invention, the retaining element rests on a face of the piston element, which face is toward the retaining element. With a bearing face adapted to this face of the piston element, an axial offset of the guides of the valve member, in the shim and of the valve retaining body, is advantageously realized by means of a sufficient relative displaceability of these parts to one another. In particular, incorrect orientations and errors of parallelism of the guides relative to one another can be compensated for in a technically easily achieved way by means of this kind of multi-part piston, with its faces adapted to one another.
In the second version, the two contact faces are advantageously embodied spherically or toroidally with concentric points of symmetry, and the bearing faces are embodied complimentary to the spherical or toroidal faces or are embodied conically. In this way, an axial offset of the guide of the valve member in the shim and of the nozzle body can be compensated for especially effectively by means of very good relative displaceability.
The retaining element is advantageously pressed onto the valve member and secured by a securing ring.
Alternatively, the retaining element can also be welded on and/or secured by positive engagement, preferably by a screw fastening.
In another embodiment, the retaining element is pressed by cold or hot deformation into grooves formed in the valve member.
Furthermore, the retaining element can also be welded to the valve member, preferably by laser welding.
It can also be provided that the retaining element is inserted into a groove, disposed in the valve member, and secured by an annular element surrounding the retaining element.
The elastic element is preferably embodied as an elastomer element, which fills a void formed between the valve member, the piston element and the retaining element.
The invention will be better understood and further objects and advantages thereof will become more apparent from the ensuing detailed description of the preferred embodiments taken in conjunction with the drawings.
REFERENCES:
patent: 2077938 (1937-04-01), Kuttner
patent: 6105879 (2000-08-01), Potz et al.
Haas Stephan
Herrmann Dieter
Kuegler Thomas
Evans Robin O.
Greigg Edwin E.
Greigg Ronald E.
Kashnikow Andres
Robert & Bosch GmbH
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