Abstract:
A solenoid valve having a magnet assembly and an injector body connected thereto, the magnet assembly and the injector body being joined together using a crimped retaining ring as the connecting element.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a solenoid valve.  
         BACKGROUND INFORMATION  
         [0002]    Such a solenoid valve is referred to, for example, in European Published Patent Application No. 0 690 223, in which the solenoid valve is used to control an electrically controlled fuel injector.  
           [0003]    Such a solenoid valve is also referred to, for example, in German Published Patent Application No. 196 50 865, in which the solenoid valve has an armature having a multi-part construction. To avoid post-pulse oscillation of an armature plate after the solenoid valve has closed, a damping device is provided on the armature.  
           [0004]    In solenoid valves, a magnet assembly, for example, maybe screwed to an injector body or fuel injector housing using a magnet lock nut. The relatively complex and costly mounting required for this screw connection may be disadvantageous. In addition, magnet lock nuts may loosen during operation of the solenoid valve, which may impair the reliability and effectiveness of the solenoid valve. Magnet lock nuts should be manufactured from a relatively hard material, such as steel alloys, for example, ETG 100.  
         SUMMARY An object of the present invention is to provide an improved option for connecting the magnet assembly and injector body of a solenoid valve.  
         [0005]    Using an exemplary approach according to the present invention, it is believed that an injector body may be mounted on a magnet assembly more simply and less costly, compared with conventional approaches. An installation tool, which is required for this operation, may be easier and more economical to provide, compared to open-end wrenches (controlled via a screw station having a force transducer) customarily used for tightening magnet lock nuts. During installation according to the present invention, the connecting element is uniformly deformed, whereas with tightened magnet lock nuts, an oval or non-uniform deformation has been observed. To achieve the connection according to the present invention, bolts may be used which, in a uniform manner or in segments of equal size, exert pressure circumferentially on the retaining ring used as the connecting element. The described connection according to the present invention may allow the cycle time to be reduced during the manufacture of solenoid valves, so that exemplary solenoid valves according to the present invention may, for example, be suitable for mass production.  
           [0006]    The retaining ring may, for example, include two crimped edges that cooperate with the corresponding grooves and/or projections of the injector body or magnet assembly, respectively. The two crimped edges help assure a firm connection between the magnet assembly and the injector body, in a robust and reliable manner.  
           [0007]    According to one exemplary solenoid valve of the present invention, the retaining ring is more elastic than the magnet lock nuts. The required elasticity is determined by particular circumstances, and the connecting ring may include, for example, stainless steel alloys, such as 1.4303 or 1.4301 alloys.  
           [0008]    The retaining ring may include a lateral recess. Such a recess may, for example, be used as a rupture point or break point, so that the retaining ring may be easily detached, to loosen the connection between the magnet assembly and the injector body. This helps ensure that no contaminations appear when the solenoid valve is disassembled. For example, the formation of particles or shavings, which may appear when loosening conventional magnet lock nuts, may be prevented. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]    [0009]FIG. 1 is a side view of a conventional solenoid valve, in which the magnet assembly and the injector body are joined together by a magnet lock nut.  
         [0010]    [0010]FIG. 2 is a schematic side view of a first exemplary solenoid valve according to the present invention.  
         [0011]    [0011]FIG. 3 is a non-cutaway side view of the solenoid valve illustrated in FIG. 2. 
     
    
     DETAILED DESCRIPTION  
       [0012]    [0012]FIG. 1 shows a conventional solenoid valve  11 . Solenoid valve  11  has a magnet assembly  12  enclosed by a sleeve  12   a.  The operating principle of the magnet assembly is not described here in detail. Magnet assembly  12  is connected to an injector body  13  via magnet lock nut  14 , which includes a screw station (not shown) on which an open-end wrench may be placed to tighten the magnet lock nut. Magnet lock nut  14  may disadvantageously deform into an oval shape during tightening. Plastic deformation of sleeve  12   a  may also result. In addition, the interaction between the nut and the wrench may produce particle deposits, thereby creating the risk of contamination of the solenoid valve and the assembly lines.  
         [0013]    An exemplary solenoid valve  21  according to the present invention is illustrated in FIGS. 2 and 3. The solenoid valve  21  includes a magnet assembly  22 , an injector body  23 , and a connecting part  28  situated on the injector body, for example, to join a pressure borehole in the solenoid valve to a high pressure accumulator.  
         [0014]    Magnet assembly  22  and injector body  23  are joined together by a retaining ring  24 , which has a first crimped edge  24   a  and a second crimped edge  24   b.  Crimped edge  24   a  cooperates with a lower groove  23   a  in injector body  23 , and the retaining ring  24  is crimped into groove  23   a  of injector body  23  to form crimped edge  24   a.    
         [0015]    Second crimped edge  24   b  surrounds a shoulder support  22   b  of a sleeve  22   a  on magnet assembly  22 . Sleeve  22   a  may, for example, be a deep-drawn component.  
         [0016]    The solenoid valve may be installed, for example, by first placing retaining ring  24  on injector body  23 , and then crimping the retaining ring into lower groove  23   a  of injector body  23 . Magnet assembly  22  is then mounted or joined to the injector body. For example, magnet assembly  22  is then pressed tightly against injector body  23 , using a hold-down, while the second crimping procedure forms second crimped edge  24   b.  It may be advantageous for shoulder support  22   b  to be elastically deformable during the second crimping procedure, thereby simplifying the creation of second crimped edge  24   b.  Plastic deformation of shoulder support  22   b  does not occur.  
         [0017]    The retaining ring thus holds the magnet assembly and the injector body together. Crimped edges  24   a  and  24   b  engage in groove  23   a  of injector body  23  and around shoulder support  22   b  of sleeve  22   a,  respectively.  
         [0018]    Finally, FIG. 3 illustrates a non-cutaway side view of the solenoid valve illustrated in FIG. 2. The components already described with reference to FIG. 2 are provided here with the same reference numbers. In this illustration, a recess  27  is provided on the outside of retaining ring  24 , which may be detached by breaking at the lateral recess  27 .