Valves and valve actuation – Electrically actuated valve – Including solenoid
Patent
1993-04-14
1994-11-01
Rivell, John
Valves and valve actuation
Electrically actuated valve
Including solenoid
251337, 2395854, F16K 3102, F02M 5106
Patent
active
053601971
DESCRIPTION:
BRIEF SUMMARY
PRIOR ART
The invention is based on an electromagnetically operated injection valve as set forth hereinafter. The opening movement of a valve closing member which acts in conjunction with a valve seat is effected by an armature within the magnetic field of an energized coil, via a needle bushing connected with the same, while the closing movement is generated by a return spring which acts via the needle sleeve on the valve closing member, which is fixedly connected with the sleeve.
A return spring is known (U.S. Pat. No. 4,944,486), which is supported on a flat front face of a setting bushing which is pressed into the flow hole of the valve core and acts on the valve closing member via the needle sleeve, in which arrangement a standard cylindrical coil spring is used, both ends of the coil are ground flat in order to obtain even wear of the support faces. The return spring is subjected to compression and, like the needle sleeve and the valve closing member, is arranged so that it can be rotated relative to the core in the flow hole.
The hydraulic forces acting on the valve closing member in the circumferential direction effect a twisting movement relative to the valve seat body, which is only partially prevented by the frictional forces which occur on the relevant contact surfaces between, the rotatable return spring and the fixed setting bush, and the return spring and the needle sleeve, and which occur due to the movement of the components concerned relative to each other.
Due to the twisting of the valve closing member relative to the valve seat body, the seating surfaces have to adapt continuously to each other, which leads to a change of the initially set valve stroke. The change of the valve stroke causes the amount of fuel which is injected per stroke to vary, thereby worsening the running behaviour and fuel consumption of the internal combustion engine.
ADVANTAGES OF THE INVENTION
In contrast, the electromagnetically operated injection valve in accordance with the invention has an advantage that twisting of the valve closing member relative to the valve seat body is prevented in a simple manner by a form-fit connection in the circumferential direction of the return spring with the fixed setting bushing and the needle sleeve.
The valve seat body and the valve closing member are thus arranged to maintain the same angle relative to each other, so that the valve stroke remains unchanged once the two sealing surfaces have adapted to each other. The amount of fuel injected per stroke remains constant over the entire life of the valve.
The measures listed herein facilitate advantageous developments and improvements of the injection valve specified hereinafter.
An embodiment of particular advantage is one in which the ends of the return spring are bent towards the longitudinal valve axis, so that the sharp edged spring ends, when inserted into the flow hole, do not scrape along its upper surface, thereby eliminating the risk of any fragments impairing the function of the injection valve. A complete U-shaped bending of the spring ends in the direction of the valve's longitudinal axis prevents the return springs from hooking into each other, for example in transport containers, which would necessitate their disentanglement prior to assembly.
DRAWING
Embodiment examples of the invention are shown simplified in the drawing and are more closely described in the description which follows.
FIG. 1 shows a fuel injection valve designed in accordance with the invention, FIGS. 2 to 5 show an embodiment example of different embodiments of a return spring in accordance with the invention.
DESCRIPTION OF THE EMBODIMENT EXAMPLES
The injection valve, shown in FIG. 1 of the drawing as an example of an electromagnetically operated injection valve for fuel injection units, in particular of mixture compressing spark ignited internal combustion engines has a core 2 which is surrounded by the magnetic coil 1 and which is used as a fuel filler neck. The magnetic coil 1 with a coil body 3 is provided with a plastic moul
REFERENCES:
patent: 189153 (1877-04-01), Towle et al.
patent: 4944486 (1990-07-01), Babitzka
patent: 5301874 (1994-04-01), Vogt et al.
Maier Martin
Reiter Ferdinand
Greigg Ronald E.
Griegg Edwin E.
Rivell John
Robert & Bosch GmbH
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