Fluid-pressure and analogous brake systems – Speed-controlled – Having a valve system responsive to a wheel lock signal
Patent
1991-12-11
1994-11-08
Oberleitner, Robert J.
Fluid-pressure and analogous brake systems
Speed-controlled
Having a valve system responsive to a wheel lock signal
148563, B60T 832
Patent
active
053621417
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The present invention is concerned with a valve block, in particular, for use with slip-controlled brake systems.
For example, DE-OS NO. 37 29 216 discloses a valve block in the valve block housing in which a plurality of hydraulic passageways establish communication between the pressure fluid supply and pressure fluid discharge ports. Valve magnets are provided in the valve block housing and are held on the valve domes, acting as adjusting elements. Passageways completely passing through the valve block housing have a ball element swaged in and acting as a blocking element to seal the passageways.
In the afore-described ball-type seal, there is a great danger of a passageway contamination as a result of abrasion during assembly of the ball. Such contamination has proved to be disadvantageous as having an adverse interfering effect on the magnetic valves during their adjusting movement, and this possible contamination requires that all residues in the passageways be removed during the rinsing operation of the valve block. The use of "king" expanders or plugs of equivalent shape has not proven effective to solve this problem.
Moreover, insertion of the valve domes and associated valve seats into the valve block housing has presented problems as these parts to be inserted also exhibit a surface-damaging force fit and are swaged, so that similarly to the afore-described ball installation, assembly of the valve domes and spots seats can add to contamination of the passageways.
It is, therefore, the object of the present invention to provide a valve block of the afore-mentioned type which, avoiding the afore-described disadvantages, permits an improved fixation of the parts inserted into the valve block without resulting in surface abrasion and thus contamination of the passages.
SUMMARY OF THE INVENTION
This object is achieved, in the practice of the invention, by use of an element constructed of an alloy material capable of having a "memory shape". The "memory shape" is such as to establish a tight fit with the receiving opening. The element is installed in another shape condition different from the memory shape which allows the element to be freely insertable into the receiving opening. Thereafter, the memory shape is restored by heating to exert a substantial pressure on the receiving opening wall. The element is in a martensitic condition when inserted into the valve block housing openings, and takes an irreversible shape condition when heated beyond the starting temperature of the austenite to thereby insure a secure fixing in the valve block housing. The ball-type closure configured as a blocking element in the passageway of the valve block housing creates a substantial thrust insuring as a result of the austenite formation, a permanent and firm fit of the ball-type member in the passageway.
It has proved to be particularly advantageous for the technical end-use application, to provide the insert parts of the valve block with a shape memory alloy of a nickel and titanium composition, enabling in response to the weight percent composition of the intermetal compound a substantial influence of the austenite starting temperature and, hence, of the conversion temperature within a range of, for example, from minus 100 degrees Celsius to plus 100 degrees Celsius. Moreover, binary alloy shape memory compositions exhibit an excellent corrosion resistance.
According to another embodiment of the principle of the invention, the binary alloy of the parts in the valve block is to be extended as the hysteresis thereof with the aid of special thermodynamic processes to realize, after the deep-temperature shaping, a simplified provision at normal room temperatures for the purpose of an easier assembly of ball, valve seat and valve dome.
Alternatively, it is provided by the invention to use a cryogenic shape memory alloy which, with a view to the high sealing and holding forces of the parts to be inserted into the hydraulic assembly, insures a high austenite strength and strong forces of fi
REFERENCES:
patent: 3783037 (1974-01-01), Brook et al.
patent: 4001928 (1977-01-01), Schweiso
patent: 4297779 (1981-11-01), Melton et al.
patent: 4631094 (1986-12-01), Simpson et al.
patent: 4929038 (1990-05-01), Reinartz et al.
Beck Erhard
Otto Albrecht
Alfred Teves GmbH
Lewis J. Gordon
Oberleitner Robert J.
Poon Peter M.
Seitter Robert P.
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