Electricity: electrical systems and devices – Housing or mounting assemblies with diverse electrical... – For electronic systems and devices
Reexamination Certificate
1998-07-28
2001-01-30
Picard, Leo P. (Department: 2835)
Electricity: electrical systems and devices
Housing or mounting assemblies with diverse electrical...
For electronic systems and devices
C361S800000, C361S677000, C439S005000, C439S132000, C439S196000
Reexamination Certificate
active
06181574
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a control device, in particular for an automatic motor vehicle transmission, including an electronic circuit, the electronic circuit is mounted on a substrate and accommodated in a housing that is sealed with respect to a surrounding fluid, and the electronic circuit is connected to electrical conductors that run outside the housing.
Such control devices are used in motor vehicles, in particular as control devices for automatic transmissions. Advanced electronic transmission control devices are integrated directly into the transmission for reasons of costs and quality. For that purpose, a housing containing the transmission controller is integrated into the transmission housing. Such a transmission controller, which is also referred to as being fully integrated, is described in Published European Patent Application 0 758 726 A2, corresponding generally to U.S. application Ser. No. 09/042,449, filed Mar. 16, 1998.
In order to be suitable for installation in a transmission housing, the control device must be capable of functioning over a wide temperature range, for example from −40° C. to 140° C. In addition, it must be sealed with respect to all customary types of transmission oil (so-called ATF oils), and finally it must be sufficiently vibration-proof (for example up to accelerations of 20 g).
It is known to seal components which are accommodated on a carrier plate mounted in the interior of the housing of the control device with a silicone rubber in commercial practice. The sealing compound is introduced at room temperature and then cured at an elevated temperature (for example at 110° C. for one hour). The housing of the control device must be very carefully sealed in order to reliably prevent the ingress of transmission oil. The ingress of transmission oil into the control device would cause the silicone rubber to swell up, as a result of which, in particular, bonding wires could be damaged, leading to a failure of the control device.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a control device, in particular for an automatic motor vehicle transmission, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type, which is reliably protected against ambient influences and which is simple to manufacture.
With the foregoing and other objects in view there is provided, in accordance with the invention, a control device, in particular for an automatic motor vehicle transmission, comprising a housing sealed against surrounding fluid; a substrate; an electronic circuit mounted on the substrate and accommodated in the housing; electrical conductors connected to the electronic circuit and running outside the housing; and a filler contained in the housing and formed of a viscous fluid compatible with the surrounding fluid.
In accordance with another feature of the invention, the filler is transmission oil.
In accordance with a concomitant feature of the invention, there are provided connection lugs connected to the electronic circuit and led out of the housing in a pressure-tight manner. The connection lugs may be connected to the electrical connecting conductors.
The advantages of the invention lie in particular in the fact that the expenditure on the manufacture of the control device is lower since the curing process for the silicone rubber is dispensed with. In addition, it is considerably simpler to introduce a viscous fluid which is compatible with transmission oil into the housing of the control device, than to seal it with silicone rubber. Finally, the invention reduces the expenditure on the sealing of the control device since, in the event of a leak, transmission oil which possibly penetrates the control device cannot bring about a functional failure of the control device. The reliability of the control device is considerably increased.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a control device, in particular for an automatic motor vehicle transmission, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
REFERENCES:
patent: 3727735 (1973-04-01), La Flame
patent: 4779460 (1988-10-01), Cruickshank
patent: 5392197 (1995-02-01), Cuntz et al.
patent: 5941137 (1999-08-01), Beer et al.
patent: 9307228 (1993-08-01), None
patent: 19501895A1 (1996-07-01), None
patent: 0758726A2 (1997-02-01), None
Duong Hung Van
Greenberg Laurence A.
Lerner Herbert L.
Picard Leo P.
Siemens Aktiengesellscahft
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