Abstract:
A motor-adjustable rear-view mirror has a housing, a mirror glass assembly, at least one mirror adjustment drive that effects alignment of the mirror adjustment drive to the reinforcement plate, in which the fastening device has at least one section for transmission of electrical energy and/or electrical signals to the mirror adjustment drive.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a motor-adjustable vehicle rear-view mirror, and more particularly to an arrangement that includes a housing that contains at least one mirror glass assembly, a mirror adjustment drive and a reinforcing plate, wherein the mirror adjustment drive acting on the alignment of the mirror glass assembly is mounted to the reinforcing plate by means of a fastening device. 
     2. Discussion of Relevant Prior Art 
     Vehicle rear-view mirrors that are motor-adjustable are well known in this field. The mirror adjustment drive is electrically connected to a power supply by very varied designs. 
     For example, connecting leads can be soldered to the respective connecting terminals of the mirror adjustment drive. The other ends of the connecting leads are brought out of the mirror housing and are connected to the power supply by means of a connector. The necessary soldering process increases the number of time consuming work steps during the assembly of the mirror. Furthermore, when mounting of the mirror, there is a great danger that the electrical leads will be crushed during the fastening of the mirror adjustment drive to the reinforcing plate. 
     In another embodiment according to the state of the art, the contacts are made by means of plug connectors that are arranged on the drive. Such plug connectors at this exposed place have to be made moisture-tight, which considerably increases their volume and makes mounting additionally difficult. Furthermore, the danger still exists that cables will be crushed, and in the worst case even parted, during mounting. 
     SUMMARY OF THE INVENTION 
     The object of the invention is to provide a secure and simple structure for the electrical connection of electrical components within a vehicle rear-view mirror. 
     This is effected surprisingly simply by a motor-adjustable rear view mirror having the following features: 
     a housing, a mirror glass assembly, at least one mirror adjustment drive that effects alignment of the mirror glass assembly, a reinforcing plate, and a fastening device that fastens the mirror adjustment drive to the reinforcement plate, in which the fastening device has at least one section for transmission of electrical energy and/or electrical signals to the mirror adjustment drive. 
     According to the present invention, the electrical energy and/or electrical signals to the mirror adjustment drive are conducted by means of at least a section of the fastening device that is made conductive. The conventionally necessary additional connection between the mirror adjustment drive and the wire harness is dispensed with. Crushing cables between the mirror adjustment drive and the reinforcing plate is avoided. Because an additional electrical connection is dispensed with, the work cost and the space requirement in the mirror housing during mounting are decreased. 
     To securely seat the mirror adjustment drive on the reinforcing plate, the fastening device can include at least three connecting elements. If these connecting elements are themselves arranged to be electrically conductive and electrically insulated from each other, the three electrical connections that are usual at the present time can be completely effected by means of the fastening device. For electrical contacting, the connecting elements can be electrically connected in the vicinity of (i.e. at or the neighborhood of) a first end with the respective connecting leads of the motor, for example in the form of contact strips, and in the vicinity of a second end with the wiring harness that supplies power and/or data signals. 
     In order to insure a compact construction, the at least sectionally conductive connecting elements extend in passage openings in the mirror adjustment drive. 
     Many conventional connecting devices can be used as the connecting elements, and if necessary can be modified as regards their electrical conductivity. For example, the connecting element can include in a simple structure a screw with a nut that holds the mirror adjustment drive and the reinforcing plate in abutment between the screw head and the nut. To insure easy mounting, the connecting element can also consist of two parts, with interengaging sections of the two parts forming a rotary snap-on closure, and with at least the mirror adjustment drive and the reinforcing plate held in abutment between the two ends of the connecting element. 
     The usual diecast parts, or else plastic parts, can be used as the reinforcing plate. Plastic reinforcing plates have the advantage, in contrast to diecast reinforcing plates, that no electrical insulation of the feedthroughs of the mirror adjustment drive, for example, in the form of sleeves introduced into the feedthroughs, is necessary. 
     The invention can also be applied to the newer vehicle rear-view mirrors that use intelligent electronics in the mirror glass housing, with analog and/or digital control. 
     The printed circuit board that receives the electronics can be directly or indirectly seated on the reinforcing plate, and the connecting elements can be connected with contact places on the printed circuit board. The contact places can be electrically connected to the wiring harness that provides the current supply and/or the digital data signals. In this manner, a digitally controllable mirror adjustment drive, which requires two digital signal leads (digital signal/ground) and two leads for the voltage supply (analog plus/ground) can be connected according to the invention by means of four conductive connecting elements. Furthermore, by combining the digital and analog ground, there is the possibility of working with only three connecting elements, which according to the invention simultaneously serve as electrical connections. 
     In order to produce a contact of the at least sectionally electrically conductive screw to the printed circuit board, an electrically conductive nut, for example a rivet nut, can be arranged in the printed circuit board, and the screw is screwed or turned onto it, while the electrically conductive rivet nut is connected on the printed circuit board to the corresponding lead of the wiring harness. 
     The provision of a printed circuit board seated on the reinforcing plate furthermore offers the possibility of contacting the heating leads of the mirror glass through the mirror adjustment drive in a similar manner to the connecting elements. In this case also, the mounting of an additional cable pair is dispensed with, and the risk of crushing an electrical connection during assembly is avoided. 
     For this purpose, two spring contact pins project through the mirror adjustment drive from the printed circuit board, and press on associated contacts of the heating system on the back side of the mirror glass carrier. 
     To protect the electrical contacts or the electronics against moisture, and in particular against corrosion-promoting salt water, the printed circuit board can be protected in the vehicle exterior mirror. The usual processes for sealing electronic components, as regards the dimensions of the sheathing structure, the setting time, and the setting temperature, do not satisfy the requirements to be placed on components in a vehicle outer mirror. Various processes for the sealing of electronic assemblies are known in the state of the art, such as molding and casting. However, this does not hold for the specific application to the exterior mirror region of motor vehicles. According to the invention, an effective protection, particularly also against vibration, can be provided by molding around the printed circuit board, for example with an elastic material, applied by an injection molding process and sheathing and sealing the printed circuit board. A melt adhesive can be used as the material, for example. The advantage of such a material also consists in that it is easy to process, requires only a short setting time and low setting temperature, and can be applied in a sufficient thickness. An effective and permanent sealing of the electronic components is thereby also insured. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is described hereinbelow in preferred embodiments, with reference to the accompanying drawings, in which: 
     FIG. 1 shows, in an exploded diagram, the individual component elements of a vehicle rear-view mirror of a first embodiment according to the invention, by way of example; 
     FIG. 2 shows in detail, the connection of the mirror adjustment drive to the plastic reinforcing plate, and the respective electrical contacts for the first embodiment; 
     FIG. 3 shows, in an outline of principles in an exploded diagram, the individual component elements of a vehicle rear-view mirror of a second embodiment according the invention, by way of example; and 
     FIG. 4 shows in detail, the screw connection of the second embodiment, with a rivet nut arranged in the printed circuit board. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 1 shows a first embodiment of the invention in an exploded diagram. According to this embodiment, the motor-adjustable vehicle rear-view mirror according to the invention includes a housing  1  that receives a mirror glass assembly, a mirror adjustment drive  3  that acts on the alignment of the mirror glass assembly, and a reinforcing plate  4  to which the mirror adjustment drive  3  is attached by means of a fastening device. The mirror glass assembly includes a mirror glass carrier  10  with a mirror glass  11  fitted onto it and a casing  17 . The fastening device at least sectionally conducts electrical energy to the mirror adjustment drive. In the embodiment shown, the fastening device includes three elements, of which only two are shown in the diagram, for the sake of clarity. These fastening elements in the form of screws  5  are inserted through corresponding openings in the mirror adjustment drive. The mirror adjustment drive  3  and the reinforcing plate  4  are brought into mutual abutment, and the screws  5  are turned through openings in the reinforcing plate  4  into nuts  7  placed behind the openings. The screws and the nuts are made of a conductive metal, copper in the present example. The reinforcement plate  4  is produced from an impact-resistant, non-conductive plastic and thus insures the electrical insulation of the three nuts  7 . In another arrangement the reinforcing plate  4  includes a diecast aluminum part, insulators being interposed between the diecast aluminum part and the screws, and between the diecast part and the nuts  7  positioned against it, in order to prevent short circuits. 
     The electrical contact of the mirror adjustment drive  3  to the side of the screw head, and the electrical contact to a power supply on the side of the nuts  7  behind the reinforcing plate, is shown in FIG. 2 for the screw connection of the first embodiment. This screw connection holds the mirror adjustment drive  3  in abutment on the reinforcing plate  4  and passes through the mirror adjustment drive  3 . A contact strip  14  is brought into direct abutment with the electrically conductive screw  5 , to produce the associated electrical contact to the drive. In this embodiment according to the invention, the screw  5  passes through the flat contact strip  14  and, with the screw head, presses the contact strip  14  against the mirror adjustment drive, so that electrical contact is produced at the same time between the contact strip  14  and the screw  5 . The respective contact strip furthermore leads to the corresponding drive connection, which is not shown. 
     On the other side of the connection, a thin metal plate  18  is arranged between the electrically conductive nut  7  and the reinforcing plate  4 , and produces an electrical contact to the corresponding lead of the wiring harness. In a further arrangement of the invention, the sections of the reinforcing plate with which the nuts are in contact are coated with a conductive material, and the associated leads of the wiring harness are electrically connected to the respective sections. 
     After the mounting of the mirror adjustment drive  3  on the reinforcing plate  4 , and the production of the necessary connections, the mirror glass assembly is clipped onto the mirror adjustment drive  3 . For this purpose, the glass carrier plate  10  to which the mirror glass  11  is adhered includes clip elements in the form of fingers  13  that are brought into engagement with the edge of the mirror adjustment drive  3 , an optical casing  17  being furthermore arranged between the mirror adjustment drive  3  and the glass carrier plate  10 . 
     In another arrangement of the invention, instead of a screw and a nut, the connecting element used is two connecting parts with interengaging sections, which together form a bayonet closure. 
     FIG. 3 shows a second embodiment of the invention, in an exploded view; here, in contrast to the first-described embodiment, a printed circuit board  8  is arranged on the back side of the reinforcing plate  4 . The electrical contact to the wiring harness is made by fitting on the printed circuit board  8  a socket into which the plug of the wiring harness can be inserted. According to this embodiment of the invention, the leads are electrically connected to the printed circuit board  8  either directly with the fastening nuts  7 , or after first passing through electrical switching circuits on the printed circuit board. In the latter case, two leads insure the power supply of the vehicle rear-view mirror, while the third lead is used as the digital signal lead for controlling and adjusting the mirror adjustment drive  3 , the digital ground of the control lead being combined with the analog ground. 
     In a further arrangement of the invention, the digital ground is provided to the mirror adjustment drive  3  separately from the analog ground. In this case, instead of three connecting elements in the form of electrically conductive fastening screws  5 , four screws pass through the mirror adjustment drive  3  and simultaneously serve to fasten the mirror adjustment drive  3  to the reinforcing plate  4  and to place the four connections of the mirror adjustment drive  3  in contact with the associated connections on the printed circuit board  8 . 
     FIG. 4 shows in a detail the electrical contact of a fastening screw  5  to the printed circuit board  8  via a nut  7 . To produce the electrical contact, and to fasten the drive  3 , the screw  5  is screwed into a nut  7 , which is riveted into the printed circuit board  8 . In order to insulate the screw from the metallic reinforcing plate  4 , an insulating sleeve  9  through which the screw  5  extends is arranged in the through-opening of the metallic reinforcing plate  4 . 
     The embodiment of the invention shown in FIG. 3 has a mirror glass heating system  12 . This is adhered to the back side of the mirror glass  11  between the mirror glass and the mirror glass carrier  10 . Heating contacts  16  are passed through the glass carrier  10  to its back side. 
     The electrical connection to the mirror heating  12  is provided by two contact pins  15 , which extend from the printed circuit board  8 , to the associated contacts  16  on the glass carrier plate  10 . These contact pins  15  are designed to be resilient, and after mounting press on the associated contacts  16 . 
     According to this embodiment of the invention, a permanently elastic material, for example, a melt adhesive, is injected around the whole printed circuit board or partial regions of it. For this, the printed circuit board is placed in an aluminum mold and the melt adhesive is injected into the mold by means of compressed air at a pressure of up to 4 bar and a temperature of about 120° C.