Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1992-05-27
1994-08-02
Oberleitner, Robert J.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
25112915, B60T 836
Patent
active
053339460
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention is concerned with an electromagnetic valve, especially for hydraulic brake systems having a slip control.
In conventionally used electromagnetic valves of the type as set out, for example, in DE-OS 37 29 216, valve sleeves are inserted into a valve housing of a steel valve block configuration and formed to be friction locked and sealed therein. When using electromagnetic valves closed in the de-energized normal condition, the valve sleeve forms the actual magnetic core of the magnetic coil. Located in the inner chamber of the valve sleeve is the magnetic armature actuating the needle valve. When used as an electromagnetic valve open in the de-energized basic position, a bushing provided at the fixing seam of the valve sleeve assumes the function of the magnetic core.
The forming of the sleeve is accomplished by means of a tool driven into the valve block housing to establish the friction-locking connection of the valve sleeve, which is thereby clamped between the valve housing and the bushing.
Especially when considering the relatively high hydraulic test pressures within the valve sleeve, the conventional friction-locking fixation of the valve sleeve requires some improvement in order to prevent the valve sleeve from loosening as a result of pressure induced thrust strain occurring between the contact surfaces.
It is, therefore, the object of the invention to enhance the holding force on the contact faces, while at the same time maintaining the friction-locking connection between valve housing, valve sleeve and bushing.
SUMMARY OF THE INVENTION
This problem, in the practice of the invention, is solved by forming interlocking features into the mating surfaces of the valve sleeve, housing and bushing, configured to resist the pressure induced separating forces on the valve sleeve.
Hence, the invention solves the problem by augmenting the friction-locking connection by a form interlock effective between the contact faces for better resisting the thrust forces within the mounting.
In one embodiment applying the principle of the invention, it has proved to be extremely effective to provide a recess in a cylindrical surface of the bushing adjacent the conventional frusto-conical surface, the recess receiving an extended length end portion of the valve sleeve, also of cylindrical shape acting as an interlocking feature.
Alternatively, the frusto-conical surface of the bushing, in the area overlain by the valve sleeve, may be provided with a fillet-type circumferential radius. The alternating bending of the clamped-in valve sleeve forms a corrugation shape establishing the interlocked shape, and hampers slipping of the valve sleeve out of the formed connection, thereby enabling high thrust forces to be transferred.
The valve sleeve is preferably constructed by deep drawing of stainless steel so that together with cold forming of the bushing connection, work hardening results in a high strength valve sleeve.
The invention will now be described in greater detail with reference to a variety of examples of embodiment.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partially sectional view of the electromagnetic valve according to the invention and a fragmentary portion of the housing in which the valve is mounted.
FIG. 2 shows an enlarged section of the valve sleeve for fixing to the valve housing according to FIG. 1 showing the formed connection of the valve sleeve.
FIG. 3 shows another embodiment of the valve sleeve formed connection to the valve housing according to the invention.
DETAILED DESCRIPTION
Referring to the drawings, FIG. 1 shows, in cross-section, the valve sleeve 3 cold formed onto the bushing 1 in the valve housing 2. As shown, the bushing 1 has one end received against a step 16 of a counterbore 17 in the valve housing 2. The valve sleeve 3 is made of non-magnetic stainless steel by deep drawing. The valve sleeve 3, in the cavity thereof, accommodates the magnetic armature 5 with the needle valve as well as the magnetic core 7. Located in a steppe
REFERENCES:
patent: 3707992 (1973-01-01), Ellison et al.
patent: 3865140 (1975-02-01), Greenwood
patent: 4624282 (1986-11-01), Fargo
Goossens Andre F. L.
Lauer Josef
Seitz Karlheinz
Alfred Teves GmbH
Lewis J. Gordon
Oberleitner Robert J.
Seitter Robert P.
Young Lee W.
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