Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1996-06-12
1997-11-04
Butler, Douglas C.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
3031131, 303900, B60T 836, F15B 13044, F16K 3106
Patent
active
056831510
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention is based on a hydraulic unit for traction-controlled brake systems of motor vehicles, as generically defined by the preamble to the main claim.
German Patent Application DE 38 10 581 A1 has already disclosed making such a hydraulic unit with a valve block from steel, making stepped receiving bores for the hydraulic portion of electromagnetically actuated valves in the block, providing securing flanges for the valves, introducing the flanges into the stepped bores, and caulking the steel material of the valve block against the securing flanges in order to positionally secure the valves in a pressure-tight manner. DE 38 10 581 A1 expressly points out that the caulking process makes it indispensible that only steel be used as the material. It says that this makes such hydraulic units heavy and makes the caulking expensive and not without problems, especially with respect to the sealing. Instead, for a light structure of aluminum, it proposes fastening at least one electromagnet valve between two aluminum plates by means of tension screws. In the state of the art that is discussed in DE 38 10 581 A1 as being disadvantageous, the securing flange of the applicable electromagnet valve is made by funnel-like flaring of the open end of a capsule-like valve dome which contains magnetically operative elements, such as the armature and magnet core. Depending on the shape of the securing flange, the counterpart face of the step of the receiving bore is embodied expensively. The material of the valve block positively displaced by the caulking surrounds the entire circumference of the securing flange. Nevertheless, this embossed connection clearly does not meet the demands made of it in terms of strength, because German Patent Application DE 40 30 571 A1 describes letting a bushing, adapted to the shape of the securing flange, into the receiving bore of the valve block and providing not only the frictionally engaged fastening of the flange attained by the embossed connection but also a positive connection, so as to counteract the thrust force acting between the contact faces of the aforementioned elements. However, this makes it more expensive to secure the hydraulic part of the electromagnet valve in the valve block.
In electromagnetically actuated valves for brake systems of the type described at the outset, known from German Patent Application DE 41 42 004 A1, the valve dome has a radially protruding securing flange, which is retained in sealed fashion in a valve block by means of a screw sleeve slipped onto the valve dome. Securing in this way, by means of the screwed sleeve and an insertion thread disposed for it in the valve block, is expensive. Moreover, such insertion threads are harder to clean than smooth stepwise recessing of the diameter of bores. Yet careful cleaning is indispensible, because unremoved chips cause leakage between the securing flange and the valve block or can get into the hydraulic circuit, which can result in severe damage or loss of function of the hydraulic unit.
ADVANTAGES OF THE INVENTION
The hydraulic unit according to the invention as defined by the body of the main claim has the advantage over the prior art that not only can the at least one valve be connected to the valve block in a way that can be achieved economically, but also a considerable savings in weight is attained because of the choice of material which is substantially lighter than steel.
By the provisions recited in the dependent claims, advantageous further features of and improvements to the hydraulic unit defined by the main claim are possible.
With the embodiment defined by claim 2, on the one hand a diversion of forces acting upon the hydraulic portion of the valve to the valve block is attained in a simple way; on the other, deformation of the valve dome is avoided, and the freedom of motion of the elements disposed inside the valve dome is reinforced by the shaping of the bushing and by caulking of the securing flange, which can be done in an intrinsically arbitrary wa
REFERENCES:
patent: 4312380 (1982-01-01), Leiber et al.
patent: 5324134 (1994-06-01), Kaes et al.
patent: 5335984 (1994-08-01), Alaze et al.
patent: 5374116 (1994-12-01), Burgdorf et al.
Patent Abstracts of Japan, vol. 16, No. 438 (M-1309) 11 Sep. 1992.
Friedow Michael
Lander Jurgen
Mueller Klaus
Staib Helmut
Butler Douglas C.
Greigg Edwin E.
Greigg Ronald E.
Robert & Bosch GmbH
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