Patent Abstract:
A device for optically measuring bores in components, preferably injection bores in fuel injection valves, having a light source and an optical measuring instrument for optically detecting the geometry of the bore. The light source illuminates an opal solid body, which rests on the component on the end of the bore opposite the optical measuring instrument.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a 35 USC 371 application of PCT/DE 02/04367 filed on Nov. 28, 2002. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention is directed to an improved device for optically measuring bores. 
   2. Description of the Prior Art 
   One device known from German Patent Disclosure DE 196 11 613 A1 has a light source that as homogeneously as possible illuminates one end of the bore embodied in a component. On the opposite end of the bore, there is a camera or other optical recording device. 
   The known device includes an optical waveguide, which at its tip opens into a conical face. The light that is fed into the optical waveguide from a light source reaches the tip, where it is scattered by the conical face and thereby illuminates the bore, preferably an injection bore of a fuel injection valve, as known for instance from German Patent Disclosure DE 196 18 650 A1. The conical tip of the optical waveguide, for optimal results, must be calibrated to the particular injection bore so that the optical measurement of the injection bore is sufficiently accurate. This effort and expense for calibration makes the measurement vulnerable to error and means increased expense. 
   SUMMARY AND ADVANTAGES OF THE INVENTION 
   The device of the invention has the advantage over the prior art that the illumination of the bore is done extremely uniformly, without requiring complicated calibration of the lighting device. The illumination of the bore is effected via an optical solid body, which is illuminated by a light source and rests on the component on one end of the bore. Because of the illuminated solid body, one end of the bore is evenly lighted, so that with an optical device, accurate measurement of the bore can be done from the other end of the bore. With the omission of calibration, the measurement can furthermore be done very quickly and hence economically. With the omission of calibration, the measurement can furthermore be done very quickly and hence economically. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other features of the invention will become apparent from the description contained herein below, taken in conjunction with the drawings, in which: 
       FIG. 1  is a first exemplary embodiment of the device of the invention; 
       FIG. 2 , a further exemplary embodiment, with a different light source; 
       FIG. 3 , a further exemplary embodiment with a further light source; 
       FIG. 4 , an exemplary embodiment in which the light source rests directly on the optical solid body; and 
       FIG. 5 , an exemplary embodiment in which the light source is disposed in the optical solid body. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In  FIG. 1 , one exemplary embodiment of the device of the invention is shown schematically. As an example of a bore to be measured, an injection bore of a fuel injection valve will be used here; the fuel injection valve is shown only in its essential parts, since such fuel injection valves are quite well known from the prior art. In a component, in this case a valve body  1 , of a fuel injection valve, there is a central bore  3 , which is bounded on one end by a conical valve seat  5 . Beginning at the valve seat  5 , there are a plurality of bores  7  embodied in the valve body  1 ; they are embodied here as injection bores  7 , and in the installed position of the valve body  1 , they connect the valve seat  5  with a combustion chamber of an internal combustion engine. An optical solid body  10 , embodied here as a glass body  10 , is introduced into the central bore  3 . The glass body  10  has a bottom face  12  and a conical outer shape, and at least in the region in which the bore  7  discharges into the valve seat  5 , the glass body rests by positive engagement with its conical outer shape on the conical valve seat  5 . By means of a light source  15 , the glass body  10  is illuminated from its bottom face  12 . In  FIG. 1 , the light source  15  is embodied as a laser or an LED (light emitting diode), which outputs a light  17  with substantially parallel rays of light that strike the bottom face  12 . From there, the light is fed into the glass body  10  and illuminates the conical outside, so that the injection bores  7  are also illuminated uniformly. It can be provided here that the conical outside of the glass body  10  is roughened, to create an even more markedly diffuse light. A consistency of the glass body  10  that ranges from diffuse to milky is also suitable, in order to achieve pronounced scattering of the light in the glass body  10 . 
   The measuring of the injection bores  7  is done by means of an optical measuring instrument  20 , which can for instance be embodied as a camera  20 . Via a control unit  22 , the camera  20  is triggered and the pictures taken by the camera  20  are stored in memory. The control unit  22  here also includes an electronic computer, which with the aid of a suitable program, on the basis of the pictures taken by the camera  20 , calculates the three-dimensional shape of the injection bore  7 . 
   In  FIG. 2 , a further exemplary embodiment of the device of the invention is shown. Serving as a light source  15  this time is an electrically operated lamp, which projects nondirectional light  17 . In order to concentrate the light  17  on the bottom face  12 , a lens or lens system  24  is disposed between the light source  15  and the glass body  10  and focuses the light  17  of the light source  15  suitably at the glass body  10 . The optical measuring instrument  20  is not shown in  FIG. 2 , for the sake of simplicity. 
   In  FIG. 3 , a further exemplary embodiment is shown. The light source  15  is once again an electrically operated lamp, but the focusing of the light here is done with the aid of a concave mirror  26 . 
   In  FIG. 4 , a further exemplary embodiment is shown. Here, the light source  15  is embodied as an optoelectronic light source and is placed directly on the glass body  10 . Hence no additional optical elements such as mirrors or lenses are needed. In this case, laser diodes or LEDs are suitable above all. 
   In  FIG. 5 , as a further exemplary embodiment, the light source is integrated with the glass body  10 , so that aiming the light source or other optical aids are unnecessary. 
   The optical solid body  10 , besides glass (essentially silicon oxide), can also comprise other opal materials. Materials that can be considered are plastics, such as plexiglass (polymethyl methacrylate), ceramic, or some other diffusing or in other words opal material. 
   The foregoing relates to preferred exemplary embodiments of the invention, it being understood that other variants and embodiments thereof are possible within the spirit and scope of the invention, the latter being defined by the appended claims.

Technology Classification (CPC): 6