Abstract:
Two parts which form a device and are joined together according to the related art are joined in a complex manner and require additional elements to produce a tight joint.  
     A device ( 1 ) is described which has two parts ( 3, 6 ), has welding pockets ( 9 ) which are capable of receiving material during the welding operation for producing a joint.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention is directed to a device.  
         BACKGROUND INFORMATION  
         [0002]    Joining two parts by a threaded joint is generally known. Thus, for example, an insertion probe of a device for determining a parameter of a medium flowing in the duct is placed in a duct at least partially by being screwed onto a wall of the duct. In addition, further sealing elements such as rubber rings for example must be present on the insertion probe to seal the duct outward. Screwing in is an additional process step after the installation of the insertion probe in the duct. In addition, a further component, namely the sealing element, must be installed. Such a device is shown in U.S. Pat. No. 5,804,718, for example.  
         SUMMARY OF THE INVENTION  
         [0003]    The device according to the present invention has the advantage over the related art that a joint, which is moisture- and air-tight without additional means, is easily established between two parts.  
           [0004]    The presence of welding pockets when two parts are welded together is advantageous, because material from at least one of the parts enters the welding pocket and is thus unable to affect the joining process between the two parts. In addition, the material which flows or is deformed during the welding operation cannot reach the environment because it is held in the welding pocket.  
           [0005]    The at least one welding pocket may advantageously be present on one or on both parts. Furthermore, the interaction of the two parts may also result in the formation of an advantageous welding pocket.  
           [0006]    It is advantageous if a second part has a first projection, on which the first part rests during welding, because a defined welding pocket which produces a tight joint between the parts is thus produced.  
           [0007]    It is advantageous if the parts are joined by orbital vibration welding, because this method subjects the parts and/or components situated on the parts to less thermal and mechanical stress compared to ultrasound welding. Thus, for example, a heat-sensitive and/or vibration-sensitive electronic component may be placed on at least one part before the welding operation without being damaged by the welding operation. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0008]    [0008]FIG. 1 shows a first exemplary embodiment of a device designed according to the present invention.  
         [0009]    [0009]FIG. 2 a  shows another exemplary embodiment of a device designed according to the present invention.  
         [0010]    [0010]FIG. 2 b  shows another exemplary embodiment of a device designed according to the present invention.  
         [0011]    [0011]FIG. 3 shows a device designed according to the present invention having a first projection.  
         [0012]    [0012]FIG. 4 a  shows a device designed according to the present invention having a second projection.  
         [0013]    [0013]FIG. 4 b  shows a device in which the two parts are welded together. 
     
    
     DETAILED DESCRIPTION  
       [0014]    [0014]FIG. 1 shows a first part  3  and a second part  6  of a device  1  designed according to the present invention.  
         [0015]    The two parts  3 ,  6  are welded together.  
         [0016]    Device  1  has, for example, a duct forming second part  6  and an insertion probe  3  forming first part  3 , which is inserted into the duct through an insertion opening  7 , at least one parameter of a medium flowing in the duct being determined using a sensor in insertion probe  3 . Such a device is known, for example, from German Patent Application 198 27 375 A1 and should be part of this disclosure.  
         [0017]    Parts  3 ,  6  are made, for example, but not necessarily, of plastic and have a central axis  21 , for example. One axial end  4  of first part  3  is designed with a T-shaped cross section, for example. First part  3  is situated at least partially in second part  6 , for example, and rests on second part  6 , part  6  having a tubular design in the area of T-shaped end  4  of part  3 .  
         [0018]    In a radial direction  27  between first part  3  and second part  6 , there is a distance d different from zero, whereby a cavity acting as a welding pocket  9  is formed between first part  3  and second part  6 .  
         [0019]    During the welding operation, material may be eroded from or pressed off at a contact surface  33  between T-shaped end  4  of first part  3  and second part  6 . This material enters the at least one welding pocket  9  and no longer interferes with the welding operation between first part  3  and second part  6 .  
         [0020]    Vibration welding, in particular orbital vibration welding, which is based on friction heating and plasticizing of parts  3 ,  6  in the area of contact surface  33 , by may be used as the welding process. It is carried out via a unidimensional, oscillating or biaxial relative motion having adjustable amplitudes of 0.25 to 2.5 mm and frequencies between 80 and 300 Hz, for example, under a simultaneously acting pressure of P=0.5 to 8.0 MPa exerted perpendicularly to contact surface  33 .  
         [0021]    [0021]FIG. 2 a  shows an additional exemplary embodiment of a device  1  designed according to the present invention.  
         [0022]    Welding pocket  9  is formed, for example, only on second part  6  by introducing a depression in an inner wall  10  of second part  6  in the proximity of contact surface  33  to form welding pocket  9 .  
         [0023]    This depression to form welding pocket  9  may also be only on first part  3  in an outer wall  11  in the proximity of contact surface  33  (FIG. 2 b ). Distance d in the radial direction between first part  3  and second part  6  may then be zero or very small.  
         [0024]    [0024]FIG. 3 shows an additional exemplary embodiment of a device  1  designed according to the present invention.  
         [0025]    Second part  6  has a first projection  12 , which extends in the axial direction, i.e., runs parallel to central axis  21  and has contact surface  33  at an axial end. First projection  12  extends centrally, for example, from a base surface  22  of part  6 .  
         [0026]    Welding pocket  9  is delimited in radial direction  27  by first projection  12  and an outer wall  11  of first part  3 , which is opposite first projection  12  in radial direction  27 . In axial direction  21 , welding pocket  9  is delimited by base surface  22  of part  6  and the T head of axial end  4  of part  3 .  
         [0027]    The space facing outward in radial direction  27  of first projection  12  also forms a welding pocket  9 .  
         [0028]    [0028]FIG. 4 a  shows an additional exemplary embodiment of a device  1  designed according to the present invention.  
         [0029]    Second part  6  has a second projection  15 , which is situated on the outer radial edge of second part  6 , i.e., on the outside opposite first projection  12  in radial direction  27  and extends in axial direction  21 . Contact surface  33  of second part  6  with first part  3  is formed on first projection  12  and not on second projection  15 . During the welding operation, the axial end of first projection  12  and first part  3  in the area of contact surface  33  are heated and plasticized, so that material  18  enters welding pockets  9  radially inward and outward.  
         [0030]    Part  18  of first projection  12  which is deformed is identified by cross-hatching.  
         [0031]    [0031]FIG. 4 b  shows the two parts  3 ,  6  of a device  1  designed according to the present invention when welded together.  
         [0032]    Contact surface  33  forms a sealing surface  24  against air and moisture.  
         [0033]    Second projection  15  of second part  6  may, but does not need to, rest on first part  3  and prevents material  18 , which is present in outer welding pocket  9 , from escaping out of outer welding pocket  9  to the outside.