Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1996-07-24
1998-02-17
Butler, Douglas C.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
3031131, B60T 836, F16K 3106, F15B 1308, F15B 912
Patent
active
057184895
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is based on a hydraulic unit for slip-controlled motor vehicle brake systems.
One such hydraulic unit is already known (DE 42 02 389 A1), in which the electromagnetically actuated valve is mounted in the valve block as a subassembly comprising a hydraulic and an electric part. The valve block has a deep, sharply stepped receiving bore, into whose bottom, small-diameter portion an inlet conduit and an outlet conduit open out. The hydraulic part of the valve, forming a pre-mounted unit engaging this portion of the bore, has two sealing rings on the circumference of its sleeve that receives a valve body, a magnet armature and a magnet core; of the sealing rings, one is disposed between the conduits and the other is disposed toward the boundary plane of the valve block and is axially supported by the electrical part of the valve. For that purpose, the electrical part engages a large-diameter portion of the receiving bore, on the side toward the boundary plane, and is retained in this bore by a positive connection by means of a retaining ring press-fitted into an undercut of the bore. In this known embodiment, the pressure fluid forces acting on the hydraulic part must be absorbed by the electrical portion and transmitted to the valve block by the positive connection. The electrical part is therefore exposed to relatively major forces. Moreover, the embodiment of this connection is expensive and requires a large amount of space.
A space-saving way that is more favorable in terms of force dissipation to fasten an electromagnet valve and a valve block of a hydraulic unit for traction-controlled brake systems is known from DE-40 30 571 A1. There, the valve comprises a hydraulic part and an electrical part mounted on it. The hydraulic part is not a premounted unit. Instead, it is made up of individual parts installed on the valve block; that is, first a valve body with a valve seat is inserted into a stepped receiving bore and secured by means of a swaged connection. A guide disk for a valve needle is inserted into the bore after that and secured. Near the boundary plane of the valve block, a bushing is then inserted into the receiving bore. The bushing serves to receive a valve sleeve, widened in funnellike fashion on its end, which receives a magnet armature and a magnet core. The valve sleeve is secured in the valve block by a swaged connection, in which material positively displaced from the edge of the receiving bore covers the funnellike sleeve portion supported by the bushing. This swaged connection is heavily loaded hydraulically and requires absolute tightness. It can therefore be achieved only in a valve block made of steel (see DE 38 10 581 A1). Adjusting the valve stroke is made substantially more difficult in this embodiment, however, because the valve stroke is to a great extent dependent on the tolerances of the aforementioned individual parts of the hydraulic part, the tolerances of the receiving bore, and the quality of the swaged connections. Defects in the hydraulic part of the valve that occur after the swaged connections have been made are no longer repairable.
ADVANTAGES OF THE INVENTION
The hydraulic unit according to the invention has the advantage over the prior art that securing of the hydraulic part is done by means of the first swaged connection in a region remote from the mouth of the receiving bore, which reduces the demands made on the material of the valve block and on the swaged connection, so that instead of steel, ductile light metal, for instance, can also be used. Sealing off of the receiving bore from the outside is now done instead by the sealing ring, placed against the boundary plane of the valve block. The load on it by hydraulic forces is advantageously absorbed by the flange secured to the second swaged connection. One quite essential advantage, however, is the use of the hydraulic part as a premounted unit, because it is not subject to any alteration of the preset valve stroke in the course of the joining process in the valve
REFERENCES:
patent: 5324134 (1994-06-01), Kaes et al.
patent: 5333836 (1994-08-01), Fukuyo et al.
patent: 5333946 (1994-08-01), Goossens et al.
patent: 5335984 (1994-08-01), Alaze et al.
patent: 5542755 (1996-08-01), Staib et al.
Friedow Michael
Guggemos Johann
Hoelle Hermann
Hueber Hubert
Lander Juergen
Butler Douglas C.
Robert & Bosch GmbH
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