Plastic and nonmetallic article shaping or treating: processes – Mechanical shaping or molding to form or reform shaped article – To produce composite – plural part or multilayered article
Patent
1997-03-20
2000-05-02
Snow, Walter E.
Plastic and nonmetallic article shaping or treating: processes
Mechanical shaping or molding to form or reform shaped article
To produce composite, plural part or multilayered article
26427217, 264278, 425125, 425117, B29C 4514, G01P 102, B29F 110
Patent
active
060569093
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to electronic circuits joined to an external fixture so as to precisely locate the circuit.
TECHNICAL FIELD
The invention relates to an electronic circuit arranged sealed in a case, whereby at least a part of the electronic circuit is to be arranged at a very small distance precisely aligned on the outer surface of the cast envelope. Such an electronic circuit can, for example, be a gear sensor with Hall IC, or an ABS sensor with Hall IC, which, to measure a rotation, must be tightly connected to a rotating system. The information thus obtained can be used to measure speed in the case of tachometers or to measure steering angle in the case of steering gears. On the one hand, such sensors are required to be very rugged and thus must be well sealed off from environmental factors. But on the other hand, the distance between the Hall IC and the rotating system must also be very small to achieve a sufficiently strong, precise signal through the Hall ICs used. This means that the case wall must be extremely thin, at least at the point of connection between the rotating system and the electronic circuit.
The problems dealt with here are dealt with in German patent disclosures DE-OS 41 42 727 and DE-OS 41 41 958, among others. To meet the above-mentioned requirements, the Hall IC was previously held in a holder which, if necessary, also received other sections of an electronic circuit at another point and the thus equipped holder was inserted centered into a case. In that example, the case itself could in turn consist of several parts which on the one hand provided, in the form of a metal sleeve or plastic sleeve, for example, for a secure, thin-walled casing of the circuit, while the case part where wall-thickness was not critical was formed by a plastic section.
The technical objective of the invention is thus to create an electric circuit that is aligned precisely in its ruggedly constructed case, whereby the circuit equipped with the case should also be economical to produce. In particular, the technical problem of the invention is to enable the case walls to be very thin if necessary and, especially in the area of this thin case-wall, to enable an electric component to be aligned very precisely on this wall.
The technical objective of the invention is furthermore to indicate a method to produce such an electric circuit as well as to disclose a mechanism with which this method can be executed.
The inventive method thus consists, in principle, in casing the electric circuit by casting round it with a slow-setting plastic. In the process, the electric circuit, which can be attached on a printed circuit board, is held in the desired position via the centering holder during the casting process and during hardening. At a time when the plastic is still soft, the centering holder is then withdrawn, whereby the electric circuit is held in the desired position by the not yet completely hardened plastic. Because the soft plastic largely fills in the resulting impression while the centering holder is withdrawn, it is thereby achieved on the one hand that the electric circuit remains in its position in the plastic case, while, on the other hand, the circuit is completely enveloped by plastic. The enveloping process can be even further improved in that, in the injection molding process, during turning back, the injection pressure is maintained in such a way that not only the recesses resulting from the withdrawal are filled in by suction forces and gravity, but at the same time the injection pressure also contributes to filling up the recesses.
The electric circuit, which is preferably attached on a printed circuit board, is centered by means of the centering holder in such a way that centering fingers spread over its surface and/or its periphery hold the board in its position during the casting and/or injection process. However, a certain displacement can occur because, due to the casting or injection pressure that acts on the printed board, it becomes warped and ther
REFERENCES:
patent: 3363040 (1968-01-01), Aoki
patent: 4470786 (1984-09-01), Sano et al.
patent: 4555086 (1985-11-01), Kiyotomo
patent: 4629597 (1986-12-01), Charlebois et al.
patent: 4888307 (1989-12-01), Spatrisano et al.
patent: 5137677 (1992-08-01), Murata
Search Report of the German Patent Office for Application P4422739.6 (no translation) May 1995.
Japanese Abstract 3-220738, Dec. 1991.
English Translation of the International Preliminary Examination Report for Application PCT/EP95/02497, Mar. 1997.
Patent Document SEL/Reg. 11 441 dated Feb. 22, 1968 (no translation).
Patent Document PA291019 dated May 14, 1959 (no translation).
Kuhn Joachim
Stumpe Reinhard
Wehling Hans Wilhelm
ITT Manufacturing Enterprises Inc.
Lewis J. Gordon
Snow Walter E.
LandOfFree
Casting mold for precisely aligning an electronic circuit with a does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Casting mold for precisely aligning an electronic circuit with a, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Casting mold for precisely aligning an electronic circuit with a will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1591720