Abstract:
An accident sensor having a fastening arrangement is provided, the fastening arrangement allowing an affixation of the accident sensor on a wall in a vehicle. The accident sensor has at least one bore hole, which has a stud in an elastic sleeve as a fastening arrangement. The stud with the sleeve is configured so that the accident sensor having the stud with the sleeve is affixed in the wall by a clamp.

Description:
FIELD OF THE INVENTION 
     The present invention relates to an accident sensor. 
     BACKGROUND INFORMATION 
     A sensor assembly in which the housing of an air-pressure sensor used for sensing side impacts is mounted on a wall in the vehicle with the aid of fastening arrangement, e.g., screws, is discussed in DE 199 23 985 A1. DE 191 06 311 A1 likewise teaches that an air-pressure sensor is installed in the wall of a partition wall between wet area and dry area in the door. The pressure channel projects into the wet area while the air-pressure sensor itself is situated in the dry area. A sealing cushion is provided, which seals the housing interior from the pressure sensor and also the housing from the partition wall. 
     SUMMARY OF THE INVENTION 
     In contrast, the accident sensor according to the present invention having the features of the independent claim, has the advantage that the accident sensor hat as at least one bore hole, which has a stud in an elastic sleeve as the fastening arrangement. The stud with the sleeve is designed in such a way that the accident sensor with the stud in the sleeve is fixed in place in the wall by clamping. This allows an uncomplicated installation of the accident sensor on the wall in the vehicle, e.g., a door panel, no tools being required for the installation. In particular, this fastening method according to the present invention enables a one-handed installation since the other hand is not required for holding a tool. The stud with the sleeve simultaneously seals the hole in the wall so as to seal the dry space in which the accident sensor is located, from the wet space in an efficient manner. This simple method makes it possible to dispense with bushings in the sensor, in particular mechanical outer supports, as in the case of, for example, the screwing technology known from the related art. Due to the elastic shape of the sleeve, the fastening force and the mechanical hardness in the connection to the door panel, and thus also the resonance, can be influenced or specified, as well. In particular, high-frequency mechanical resonances are able to be damped in efficient manner in the process. On account of its design, the accident sensor according to the present invention provides considerable cost savings. 
     According to the exemplary embodiments and/or exemplary methods of the present invention, the accident sensor is either an acceleration sensor, structure-borne noise sensor or air pressure sensor. It is also possible to install a surround sensor system utilizing the fastening arrangement according to the present invention. Among such surround sensors are video, radar, ultrasound or lidar sensors. 
     The wall may be a door panel, which separates the wet area from the dry area inside the vehicle door. A vehicle door usually has a wet area, which is on the side on which the window of the vehicle can be lowered. 
     The stud is usually made of metal, but could also be made of plastic. The stud provides the clamping as a result of its shape, which then leads to an expansion by the sleeve, so that the affixation of the accident sensor is achieved when the stud with the sleeve is guided through the bore hole in the wall. The sleeve has an elastic design, so that it is typically made of a rubber-type or other pliable plastic material, such as silicon. The stud can be preassembled inside the elastic sleeve in the delivery state. Depending on the exact design, the affixation is implemented in such a way, for instance, that the sleeve in its original state, e.g., with preassembled stud, is first slid through the anchoring hole whereupon the stud is pressed into the elastic sleeve, up to an end position, which causes an expansion of the sleeve and thus clamping of the sensor. Because of the clamping, it is impossible for the sleeve with stud, and thus the sensor itself, to simply fall out once it has been pushed through the bore hole in the wall, but instead can be pulled out only with great force. 
     Advantageous further developments can be gathered from the further description herein. 
     It is especially advantageous that the stud is designed in such a way that the bolt causes the sleeve to widen and/or spread apart when inserted into the sleeve, the widening or spreading ultimately bringing about the clamping. In other words, the stud can be guided through the wall by itself, but with the sleeve, which is elastic, this can be done only by the use of force in order to compress the sleeve when passing it through, the sleeve relaxing again after the through-feeding and thereby generating resistance against a retraction. This resistance may be produced by widening, i.e., expansion, or by spreading, for instance in that the stud breaks through the sleeve and thereby widens it at the tip. 
     Furthermore, it is advantageous that the stud has at least one first section for the clamping, and a subsequent second section, which is thinner than the first section. This makes it easy for one section of the sleeve to enlarge or spread apart but the next section then not to do so. This considerably facilitates the manageability of the fastening arrangement according to the exemplary embodiments and/or exemplary methods of the present invention. 
     In an advantageous manner, the stud can also have a third section, which third section has at least one barb. This barb makes it more difficult for the stud to be pushed out of the sleeve. Other geometric designs of the stud that do not constitute a barb yet nevertheless offer resistance against retraction are possible here as well. This third section may largely be identical to the first section since the enlargement may simultaneously be designed as a barb as well. 
     In an advantageous manner, the stud elongates the sleeve in its length when inserted into the sleeve. This leads to excellent sealing of the sleeve at the door panel because the sleeve expands in length upon insertion of the stud into the sleeve. As soon as enough tension has then been generated, the constriction of the sleeve slides over the stud, the diameter of the sleeve increases, and the force elongating the sleeve diminishes at the same time, so that the plug of the stud is pulled toward the hole to be sealed and is pressed against it. Given adequate dimensioning, this ensures or improves the sealing effect of the stud. 
     In an advantageous manner, the sleeve has at least one rib or at least one detent that prevents the sleeve from sliding back once it has been threaded through the door wall. 
     As mentioned earlier, the stud can be designed in such a way that it penetrates the sleeve when being inserted, so that the sleeve is forced apart or engages behind the stud, and thereby also prevents the stud from being pushed out of the sleeve. The spreading results in an effective clamping effect. 
     The accident sensor is designed in such a way that the accident sensor releases a plug for the connection of cables only if the stud with the sleeve has been slipped into an end position for an affixation of the accident sensor. This end position means that the stud or the sleeve rests against the accident sensor, so that the clamping effect retains the accident sensor on the wall in an optimal manner. If the stud with the sleeve is not yet resting against the accident sensor, then the stud with the sleeve blocks the access to affix the cables on the accident sensor. This provides an additional safety mechanism, so that the accident sensor is safely installed by the installer. 
     Exemplary embodiments are depicted in the drawing and are explained in greater detail in the description below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows an installation position of the accident sensor according to the present invention. 
         FIG. 2   a ,  FIG. 2   b , and  FIG. 2   c  show the installation position or the manner in which the stud is inserted into the sleeve. 
         FIG. 3   a ,  FIG. 3   b , and  FIG. 3   c  show three examples of one development of the stud-sleeve system. 
         FIG. 4  shows an additional example for the manner in which a stud is inserted into the sleeve. 
         FIG. 5   a ,  FIG. 5   b , and  FIG. 5   c  show spreading of the sleeve when the accident sensor is fixed in place. 
     
    
    
     DETAILED DESCRIPTION 
     According to the exemplary embodiments and/or exemplary methods of the present invention, an accident sensor with a stud and a sleeve, which are guided through a bore hole in the accident sensor, is fixed in place on a wall in the vehicle in that the stud with the sleeve is threaded through a hole in the wall and supports the accident sensor by a clamping effect. Studs or screws may be used in addition so as to define the installation position more precisely. The more precise installation position can also be aptly defined by the use of the use of a plurality of studs with sleeves. In this context it is possible that the stud is already inside the sleeve before it is fixed in place in the wall or that it is inserted into the sleeve only for the mounting in the wall, after the sleeve has already been passed through the hole in the wall and the clamping effect is produced by an expansion of the sleeve behind the hole in the wall. 
       FIG. 1  schematically illustrates how an air pressure sensor  10  is installed in a vehicle door  11  with the aid of the affixation concept according to the present invention. Inserted through the upper opening in wall  11  is a pressure channel  12  of air pressure sensor  10 , in order to be able to measure the air pressure inside the wet space. A bolt  15  with an elastic sleeve  16  is threaded through a second opening of wall  11 , bolt  15  causing an expansion  14  in sleeve  16  after having been passed through the opening in the wall, thereby producing a clamping effect that retains sensor  10  on wall  11 . In the installed state, stud  15  with sleeve  16  releases a plug or a socket  13  on air pressure sensor  10  to which the signal-conveying cables are able to be connected. This results in an efficient protection against a faulty installation in that the electric connection to air pressure sensor  10  is released only if stud  15  with sleeve  16  is installed correctly. 
       FIG. 2   a  once again shows the installed state of air pressure  23  with sleeve  24  and stud  20 , sleeve  24  having an expansion  22  behind the opening in the wall. The sleeve is denoted by  24  in this instance, and sleeve  24  has expansions  21  that engage behind air pressure sensor  23  and in the mounted state retain the air pressure sensor in this manner by the contact pressure by stud  20 . Sleeve  24  is able to be appropriately adjusted with regard to hardness in order to absorb a corresponding force. 
       FIG. 2   b  illustrates how stud  20  is partly inserted into sleeve  24 . In the process, a first section  25  is guided through a constriction  22 , tip  25  of stud  20  being followed by a section that narrows again. This is followed by an expansion  26  in the stud, which will result in the widening of constriction  22 . This expansion  26  is in turn followed by a narrowing  27  and then by another expansion  28 , which then also functions as barb. Next is a section  29  with a uniform thickness until the end. 
       FIG. 2   c  now illustrates how stud  20  has shifted further and causes widening of sleeve  24  in constriction  22  by its expansions  26  and  28 . Identical reference numerals are used for the same elements. 
       FIGS. 3   a  to  c  show possible realizations for the one-handed installation stud having an integrated barb, made up of an elastic sleeve and rigid locking stud. In the upper drawing,  FIG. 3   a  shows the manner in which the stud is threaded through constriction  33 , that is to say, by its tip  35 , which will not cause an expansion yet. In the lower figure, expansion  34  with the barb then causes widening of constriction  33 . Adjacent is a uniform cylinder  37  up to the end of stud  30 . Between constriction  33 , a section  36  that is relatively thin, is provided as well. In this case, too, identical elements are denoted by the same reference numerals. 
       FIG. 3   b  shows an additional configuration, in which tip  35  penetrates the sleeve more deeply.  FIG. 3   c , on the other hand, shows a puncture through sleeve  31 , with section  36  engaging behind tip  35  of stud  30 , thereby making it effectively impossible to slide the stud back. 
       FIG. 3   a  thus shows a simple development in which the bolt is covered.  FIG. 3   b  shows a production-optimized design for the sleeve, and  FIG. 3   c  shows a design that provides additional mechanical resistance. 
       FIGS. 4   a  through  c  show a realization of the sealing function of the stud. The bolt as a whole is denoted by reference numeral  40  throughout, and the sleeve by  41 ; the section engaging behind the wall by  47 ; the expansion of the stud by  45 ; the constriction of the sleeve by  43 , and the tip of the bolt by  42 . The section following the expansion of bolt  45  is denoted by  46 . When sleeve  41  slips over the stud and the expansion builds up at constriction  43 , the expansion in the sleeve relaxes, and the expansion is drawn into the anchoring hole in the vehicle panel. In this way the hole in the panel is securely sealed by the combination of stud and sleeve. Here, too, identical elements are denoted by the same reference numerals. The arrows indicate the direction of force. 
       FIGS. 5   a  to  c  show different configuration options of the affixation arrangement according to the exemplary embodiments and/or exemplary methods of the present invention. According to  FIG. 5   a , the fastened state of stud  50  with sleeve  53  in wall  51  is illustrated, the pressure sensor being denoted by  52 . Tip  55  of the sleeve and the expansion at former constriction  54  are illustrated. In  FIG. 5   b  it can be seen that expansion  54  is inside the anchoring hole. The affixation then essentially takes place by frictional force and less by tractive force in the sleeve.  FIG. 5   c  shows the complete expansion of sleeve  53 , which is illustrated by expansion elements  55 . In this way, stud  50  retains accident sensor  52  on wall  51 .