Abstract:
An electric motor, includes a stator, which is composed at least of stamp-packed tooth segments, the tooth segments being able to be slid together radially in the manufacture and being able to be held together by retaining elements slid on axially.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to an electric motor and a method for manufacturing an electric motor. 
       BACKGROUND INFORMATION 
       [0002]    European Published Patent Application No. 1 322 021 describes a stator in which the teeth of the stator are axially inserted into a hollow cylindrical annular body. Caps, having electrical plug connections, are plugged onto both ends. The large mass and thus costly manufacture of the motor is a disadvantage. 
         [0003]    U.S. Pat. No. 6,226,856 also describes a stator in which the teeth of the stator are inserted axially into one another. 
         [0004]    U.S. Pat. No. 6,359,355 describes a stator in which the segments are indeed brought together radially, but they are retained by a surrounding “circular pattern  28 ”. 
       SUMMARY 
       [0005]    Example embodiments of the present invention provide a device and a method by which the manufacture of an electric motor and an associated series may be simplified and by which the protection of the environment may be improved. 
         [0006]    According to example embodiments of the present invention, an electric motor includes a stator, which is at least composed of stamp-packed tooth segments, the tooth segments being able to be slid together radially in the manufacture and being able to be held together by holding elements slid on axially. 
         [0007]    An advantage in this regard is that less mass is required for the stator pack, in particular no ring surrounding the tooth segments for retaining the tooth segments by shrink-fitting. Thus the protection of the environment is improved. Moreover, manufacturing is possible quickly and simply and in a highly automated and thus cost-effective fashion. In this regard, the segments are simply slid together radially and retaining elements are then plugged on axially. 
         [0008]    It is furthermore advantageous that the stator pack may be inserted into various housing systems as a preassembled unit, which improves the flexibility and the modular system diversity. In this regard, it is only necessary to keep one stator pack in stock for multiple varying housing types of the electric motor as a whole. 
         [0009]    The stator pack is also referred to as a stator for the sake of simplicity. 
         [0010]    The retaining elements may be connected to the tooth segments in form-locking fashion. An advantage in this regard is that portions of the retaining force are producible by a simple supplementary part that may be plugged on axially. 
         [0011]    The retaining elements may be inserted by pegs into holes of the tooth segments. In particular, the pegs are oriented in the axial direction. An advantage in this regard is that the retaining element is simple to manufacture and that a sufficiently high stability may be produced by simple connecting devices. 
         [0012]    The tooth segments may have groove and tongue for form-locking interconnection in the circumferential direction. An advantage in this regard is that a form-lock may be produced in the circumferential direction by simply shaping the tooth segments. Because of the pegs of the retaining elements, the tooth segments would theoretically only be able to rotate around the pegs. However, since the groove and the tongue are designed such that they are insertible into each other in the circumferential direction, a radial motion is prevented. The results from the fact that the groove-tongue form-lock is situated on both sides in the circumferential direction. 
         [0013]    The retaining elements may include electrical connections for producing the interconnection of the windings of the individual tooth segments. In particular, the retaining elements have a stamped grid extrusion-coated with plastic. An advantage in this regard is that the wiring, that is, the production of the series or parallel connection, may be executed particularly quickly and simply. The retaining element may also be designed to have plug contacts for establishing electrical plug connections to electric lines. In this instance, the tongues of the plug contacts are parts of the bent stamped grid, that is, of a stamped-bent grid instead of a stamped grid. 
         [0014]    Each tooth segment may have an axially slid-on end cap, in particular including grooves for running wires. An advantage in this regard is that the form of the winding may be influenced better and thus a high degree of copper filling may be produced. This yields a high utilization of the motor while minimizing losses of the motor. 
         [0015]    Among features in the method for manufacturing an electric motor are that in the manufacture the tooth segments are radially slid together and subsequently are axially slid on by retaining elements, in particular for holding together the segments. 
         [0016]    An advantage in this regard is a very quick and simple manufacture. The manufacture is thus also cost-effective. 
       LIST OF REFERENCE CHARACTERS 
       [0000]    
       
           1  tooth segment, stamp-packed 
           2  hole 
           3  tongue 
           4  groove 
           5  retaining element 
           6  peg 
           7  stator, complete 
           8  projection 
           9  insulating paper 
           10  end cap 
           11  coil support 
           12  grooves 
           13  wire guide 
           14  winding 
       
     
         [0031]    Example embodiments of the present invention will now be explained in greater detail with the aid of figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0032]      FIGS. 1 through 3  show the assembly of the stator from the tooth segments. 
           [0033]      FIGS. 4 through 11  show the manufacturing steps of the fully wound tooth segment in order. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]    The motor according to example embodiments of the present invention includes a stator made up at least of tooth segments. 
         [0035]      FIGS. 4 through 11  show the manufacturing steps of the fully wound tooth segment in order. 
         [0036]      FIGS. 1 through 3  show the assembly of the stator from the tooth segments. 
         [0037]    In the following, the figures are explained in more detail in sequence. 
         [0038]      FIG. 4  shows a tooth segment  1 . It has a groove  4  and a tongue  3  and a projection  8  produced by the stamp-packing process. In addition, a hole is provided for inserting pegs  6 . 
         [0039]      FIG. 5  show the insulating paper  9  that is slid onto the tooth segment. 
         [0040]      FIG. 6  shows tooth segment  1  having insulating paper  9  slid onto it. 
         [0041]      FIG. 7  shows an end cap  10 , which has grooves  12  for guiding wires and a coil support  11  for securing the winding and recesses as wire guides  13 . 
         [0042]      FIG. 8  shows a tooth segment having slid-on end caps  10 . 
         [0043]      FIG. 9  shows a tooth segment subsequently wound by winding  14 . 
         [0044]      FIG. 10  shows retaining element  5  having pegs  6 . Pegs  6  are shown protruding and oriented in the axial direction. Retaining element  5  may be made of plastic. 
         [0045]      FIG. 11  is a cross-sectional view through fully wound tooth segment  1 . Winding  14  is surrounded by insulating paper  9 . 
         [0046]      FIG. 1  shows stamp-packed, fully wound tooth segments  1 , which are radially slid together when manufacturing the stator. In the process, the respective groove  4  and tongue  3  of adjacent tooth segments meet and thus secure the connection of the two respective tooth segments in the radial direction. 
         [0047]      FIG. 2  shows how retaining elements  5  are slid on in the axial direction on the axial end regions and are connected by their pegs  6  in a form-locking manner to the tooth segments. For this purpose, pegs  6  are inserted into holes  2  of the tooth segments. 
         [0048]    Thus, retaining elements  5  give the stator its cylindrical shape and hold it together. On the one hand, they thereby limit the axial mobility of tooth segments  1 , and, on the other hand, they prevent the tooth segments from radially moving away from pegs  6 . For the pegs are inserted in holes  2 . 
         [0049]      FIG. 3  shows the stator having retaining elements  5  slid on. 
         [0050]    In other exemplary embodiments of the present invention, a differently shaped element provided with additional functions may be used in place of retaining element  5  designed as a ring having pegs. The element may also be executed as a cap, for example. Furthermore, it may also be executed as having electrical connections integrated into the retaining element. Particularly advantageous for this purpose is a design having a stamped grid that is extrusion-coated with plastic and is thus produced as a retaining element. The stamped grid is designed such that the wiring is producible by stamping the retaining element. For this purpose, various regions are respectively stamped out of the retaining element and thus the remaining stamped grid is designed for wiring.