Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Reexamination Certificate
1999-05-28
2001-02-20
Oberleitner, Robert J. (Department: 3613)
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
C251S129020, C251S367000, C137S550000, C137S599050
Reexamination Certificate
active
06189985
ABSTRACT:
PRIOR ART
The invention is based on a magnet valve, which is intended for insertion into a receiving bore in a hydraulic block of a slip-controlled hydraulic vehicle brake system.
One such valve is known from German Patent Disclosure DE 44 12 648. The known valve has a rodlike base body, which is insertable by one end into a receiving bore of a hydraulic block, so that it can be hydraulically connected to other components of the vehicle brake system. A valve dome, in which an armature is axially displaceably received, is mounted on an end of the base body that protrudes from the hydraulic block. The base body is provided with an axial through bore into which an armature-actuated valve tappet protrudes that in turn actuates a valve closing body. A valve seat part is inserted into the through bore of the base body from another end, located in the receiving bore. For actuation of the known magnet valve, a coil is slipped onto the valve dome.
The base body of the known magnet valve is a turned part; that is, it is produced by metal-cutting machining. To secure it in the receiving bore of the hydraulic block, a radially protruding securing flange is mounted on it; this requires that it be provided with a groove, countersunk feature or the like, or in other words with an undercut. In addition, a transverse bore is provided in the region of the valve closing body and of a valve seat, through which bore fluid can flow out after passing through the valve seat. The transverse bore requires a second work operation, in which the base body has to be clamped to a drilling machine. This makes the base body expensive to manufacture. Another factor is that as the material for the base body, a steel must be used that can be machined well in metal-cutting fashion and that moreover is be readily weldable, to enable the valve dome to be welded on in fluid-tight fashion. For a steel to be both readily machinable by metal cutting and weldable requires meeting two contrary demands. For the base body of the known magnet valve, a special steel is therefore used, which can be both machined by metal cutting and welded, but is consequently relatively expensive.
ADVANTAGES OF THE INVENTION
The base body of the magnet valve of the invention enlarges its cross section from its two face ends up to a point of maximum cross section, for instance in graduated or conical form, or has a constant cross section over a longitudinal portion. The point of maximum cross section may also be located on one face end. It may also be located in the middle region of the base body, for instance in the form of an annular disklike securing flange that is integral with the base body (claim
3
). For the through bore of the base body, the fact that its cross section remains exclusively enlarged or constant from the face ends up to a point of maximum cross section means that the bore cross section remains reduced or constant. The base body of the magnet valve of the invention accordingly has no tapered feature between its face ends and the point of maximum cross section, and thus has no undercut from the direction of its face ends. This has the advantage that the base body can be produced by extrusion, in particular by cold extrusion. This has the advantage on the one hand of employing a fast, economical production process. It has the further advantage that an economical reforming steel with the property of good weldability can be used for the base body.
It is advantageous in accordance with claim
1
to provide grooves, extending longitudinally from the face end to be inserted into the receiving bore of the hydraulic block until the region of the valve closing body and the valve seat, in the form of outlet conduits in the through bore of the base body. These grooves can be produced in the extrusion process, so that no further operation or work step is needed. Another advantage of this feature of the invention is a 180° deflection of the outflow: Fluid flowing through the valve seat axially from the face end located in the receiving bore is deflected by 180° into the grooves acting as outlet conduits in the wall of the through bore of the base body, that is, by 180°. This deflection of the flow through the valve lends an impetus to the valve tappet that reinforces the opening of the magnet valve.
Mounting an end piece on the face end of the base body to be inserted into the receiving bore of the hydraulic block, as defined by claim
7
, has the advantage that the base body itself can be made shorter, thus facilitating its production by extrusion. A further advantage is that the outflow from the axially parallel grooves in the through bore can be deflected radially to the circumference in a simple way, without requiring a further operation on the base body, and at the circumference it reaches an outlet conduit that discharges at the circumference of the receiving bore of the hydraulic block.
REFERENCES:
patent: 4420140 (1983-12-01), Gachot
patent: 4621788 (1986-11-01), DeLew et al.
patent: 4993684 (1991-02-01), Prina
patent: 5356211 (1994-10-01), Fritsch
patent: 5795038 (1998-08-01), Fuller et al.
patent: 5887956 (1999-03-01), Rausch
patent: 5931179 (1999-08-01), Megerle et al.
Fritsch Siegfried
Kirschner Martin
Greigg Edwin E.
Greigg Ronald E.
Nguyen Xuan Lan
Oberleitner Robert J.
Robert & Bosch GmbH
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