Metal working – Method of mechanical manufacture – Electrical device making
Reexamination Certificate
2000-01-19
2001-10-23
Sax, Steven (Department: 2773)
Metal working
Method of mechanical manufacture
Electrical device making
C198S345300
Reexamination Certificate
active
06305075
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains to a shifting device for the transmission of a motor vehicle with a curved printed circuit board inserted under the curved cover and to a process for manufacturing this curved printed circuit board with inserted components.
BACKGROUND OF THE INVENTION
The shifting movements performed at the gearshift lever of the shifting device may be electronically transmitted to the transmission.
Shifting devices whose gearshift lever passes through a cover, at which the shift positions are optically displayed, have been known. The existing shift position symbols are usually illuminated permanently, and the corresponding symbol is illuminated more strongly in order to show to the driver of the vehicle which gear has been selected.
Such a shift position display is disclosed in, e.g., DE 296 06 501.3. Fatigue phenomena occur in the cables moved along with the gearshift lever, and the illumination of the shift position symbols is not perfectly homogeneous.
Shifting devices which transmit a signal corresponding to the shift position of the gearshift lever to a control unit of the transmission via sensors have been known, e.g., from DE 196 08 981.6. The function of detecting the signal, of coding, of processing and of transmitting are carried out at different points of the shifting, and the signals are transmitted via cables, plugs and additional elements. This design is error-prone and cost-intensive because of the many interfaces.
Printed circuit boards which can be assigned to one of two groups are currently known in the state of the art. Distinction is made between flexible printed circuit boards and rigid printed circuit boards.
Flexible printed circuit boards are difficult to handle because of the flexibility of the material of the printed circuit board during the insertion of components and mounting, and their dimensional stability is insufficient in the particular case. They are very expensive and are therefore unacceptable in the automobile industry because of the large numbers needed.
Rigid printed circuit boards are less expensive than flexible printed circuit boards and can be processed in a simpler manner.
They have a flat surface shape and can be provided with conductor strips on the top side and the underside. The components are inserted on these printed circuit boards in the flat state, soldered, and cooled after soldering.
So-called SMD (surface mounted devices) components have already proved successful for insertion on the printed circuit boards. These are components that are placed on the surface.
They require no holes in the printed circuit board any more to position and insert them, but they are placed on the solder paste applied to the printed circuit board beforehand by screen printing and are held in the position into which they are brought by an automatic inserting unit by the adhesive forces of the solder paste until the final soldering.
Printed circuit boards may be through hole plated, i.e., they may have conductor strips on both sides of the printed circuit board, wherein the conductor strips are connected to one another at desired points by the conductor strips having through holes, which pass through the corresponding conductor strips to be connected and the printed circuit board, wherein this hole is lined with conductive material in order to establish the conductive connections between the perforated conductor strips to be connected. These rigid, flat printed circuit boards are installed in the flat state.
It is disadvantageous that a rigid printed circuit board cannot be bent later, i.e., after the components have already been inserted and it has been soldered, in order to adapt it, e.g., to a desired mounting situation, which would require a curved printed circuit board.
Even though a rigid printed circuit board is flexible to some extent, this flexibility is not sufficient to impart a permanent curvature to the printed circuit board; stresses, which would be transmitted to the conductor strips and to the terminals of the components, are generated in the material during the subsequent bending of the printed circuit board after soldering and the complete insertion of the components. A printed circuit board thus bent would display stresses in its material and could not withstand the loads occurring in the vehicle due to the prevailing operating conditions, such as vibrations, variations in temperature, etc.; the stress load of the components would unavoidably lead to preprogrammed failure of the printed circuit boards, the components or both together.
For example, small glow lamps, light-emitting diodes, etc., which are installed on flat printed circuit boards and are used to illuminate the shift position symbols, may be located under the cover of shifting devices, which usually have a bent or curved surface contour in order to optically better harmonize with the pivoting movement of the gearshift lever. However, problems linked with the gaping of the contour of the cover of the shifting device and the contour of the installed printed circuit board keep occurring in this case; e.g., the distance between the illuminating means and the symbols to be illuminated is not equal, which may lead to an undesired difference in the intensity of the illumination.
SUMMARY AND OBJECTS OF THE INVENTION
The primary object of the present invention is to provide a shifting device that has no cables and connectors moving along with the gearshift lever, requires a minimum number of components and makes possible an optimal illumination of the shift position symbols.
This object is accomplished according to the present invention by the shifting device having a curved printed circuit board, which is adapted to the curvature of the cover of the shifting device and accommodates all the necessary electronic components of a circuit, e.g., sensors, light-emitting diodes and processors on this one printed circuit board.
The shifting device according to the present invention has a curved printed circuit board, which is optimally adapted to the curvature of the cover of the shifting device and is mounted at a short distance of less than 10 mm under the cover of the shifting device. It may be locked, e.g., in a transparent plastic plate, which may be provided with the shift position symbols. In addition, space can be saved in the shifting device due to the compact design, and the weight can be reduced.
Due to the curvature of the printed circuit board being substantially exactly adapted to the curvature of the cover of the shifting device, it can be achieved that a homogeneous, diffuse illumination of the individual shift position symbols can be seen on the curved cover of the shifting device. This advantage results from the distance between the light-emitting diodes installed on the printed circuit board and the shift position symbols being substantially constant.
All the electronic components that are necessary for the detection of the position of the gearshift lever and for the illumination of the shift position symbols are installed in this one printed circuit board. At least one activating element, e.g., a magnet, is carried by the gearshift lever. During the selection of the gears, the magnet is moved along the sensors installed on the printed circuit board, and it induces in them a signal, which can be subjected to further processing in a processor. The activating elements corresponding to the sensors may be installed directly at the gearshift lever or be preferably arranged at a blind-type cover of the shifting device, which is carried by the gearshift lever during the movement.
The sensors are preferably installed such that they pass through the printed circuit board, i.e., the printed circuit board has openings at these points, i.e., holes, via which or in which the sensors can be installed. The electronic components are installed on one side of the printed circuit board, called the top side. At least one activating element is carried by the pivoting of the gearshift lever and is moved along the sensors, which pass through the pri
Ersoy Metin
Gassmann Hans-Joseph
Lemforder Metallwaren AG
McGlew and Tuttle , P.C.
Sax Steven
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