Abstract:
The invention relates to a cooling circuit pump for a motor vehicle, having a stator which is arranged in a motor housing ( 14 ) and in which a rotatably mounted rotor is received. It is proposed that the stator ( 12 ) is received in the motor housing ( 14 ) in a positively locking manner.

Description:
[0001]    The invention relates to a cooling circuit pump for a motor vehicle. 
         [0002]    The German patent publication DE 10 2009 028 144 A1 discloses a cooling circuit pump for a motor vehicle, the former having a hydraulic part as well as an electric motor. When such water pumps are used in the automotive field, said pumps are exposed to considerable vibration and temperature loads. This results, for example, during use as a so-called auxiliary water pump which increases the climate comfort in the motor vehicle, improves the flow of the coolant and supports the heating circuit. In so doing, the use of residual heat is facilitated when the engine is turned off. It is known from the prior art how to fasten the stator of the electric motor to the motor housing by means of screw or adhesively bonded connections. 
       SUMMARY OF THE INVENTION 
       [0003]    It is the aim of the present invention to mount the stator of the electric motor such that said stator is sufficiently fixed when inertia forces resulting from vibration loads occur and is simultaneously able to compensate for the dimensional tolerances caused by temperature. 
         [0004]    In contrast to the solutions known to date, it is now proposed according to the invention that the stator is received in the motor housing in a positively locking manner. As a result, complicated production equipment is no longer required as is the case for bonding or screwing operations. 
         [0005]    The stator which is constructed from a laminated core is preferably fastened by means of a snap hook device on or in the motor housing. 
         [0006]    To this end, snap hooks are disposed on the inside of the laminated core radially around the circumference of the motor housing in a distributed manner, said snap hooks engaging around the laminated core in a positively locking manner with the aid of latching lugs formed on the ends thereof. The snap hooks are thereby attached to a support ring, wherein support ring and snap hooks are preferably configured as one piece with the motor housing, e.g. manufactured by means of an injection molding process. 
         [0007]    A tolerance compensation element is disposed between support ring and the laminated core of the stator, which element, as previously mentioned, ensures that expansions due to temperature can be absorbed. In addition, the tolerance compensation element allows the stator to be easily mounted in the motor housing. 
         [0008]    In a second advantageous embodiment, the snap hooks are fastened to a rotor can. 
         [0009]    A further modified embodiment consists of the laminated core having a step or ledge on which the latching lugs of the snap hooks engage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  shows a cross section through an electric motor of a cooling circuit pump. 
           [0011]      FIG. 2  shows a corresponding top view of the electric motor. 
           [0012]      FIG. 3  shows a cross section through an electric motor of a cooling circuit pump in a second embodiment and 
           [0013]      FIG. 4  shows a cross section through an electric motor of a cooling circuit pump in a third embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In  FIG. 1 , an electric motor is depicted in cross section, which preferably is used in cooling circuit pumps in the automotive field. Design and function of such cooling circuit pumps are generally known, for example from the German patent publication DE 10 2009 028 144 A1 cited at the beginning of the application. The disclosure content of said patent publication will be explicitly referred to if necessary. 
         [0015]    Only the components of the cooling circuit pump are however described below which are necessary to explain the invention. The stator  12  comprising a laminated core is received in a motor housing  14  of the electric motor  10 . In order to mount the stator  12  in a positively locking manner, six snap hooks  16  are provided which are uniformly distributed on the circumference of the motor housing  14 . The snap hooks  16  attach thereby in the region of a support ring  18  which is preferably manufactured as one piece together with the snap hooks  16  and the motor housing  14  in an injection molding process. The snap hooks  16  have corresponding latching lugs  20  on the free ends thereof, said latching lugs engaging in a positively locking manner around the uppermost lamella  13  of the laminated core in the installed state; thus enabling the entire laminated core to be reliably fixed in the motor housing  14 . A tolerance compensation element  22  which is correspondingly matched to the diameter of the lamellae or the support ring  18  is disposed between support ring  18  and the lowermost lamella  15  of the laminated core, said tolerance compensation element being embodied as an elastomer ring or as a metal corrugated washer. 
         [0016]    Because the electric motor  10  has to be reliably sealed off from the hydraulic part of the cooling circuit pump during installation, a rotor can or pot  24  is introduced into the motor housing  14  as depicted in  FIG. 1  which is concentrically enclosed by the stator  12  on the outside and the interior  26  of which accommodates the rotor (not depicted) of the electric motor  10 . 
         [0017]    The assembly takes place by the mating of the stator  12  and the engaging of the latching lugs  20  on the uppermost lamella  13  of the laminated core after excessive pressure has been applied to the elastic tolerance compensation element  22 . In comparison to a radial mounting of the stator, for example by means of screws or adhesive bonding, the axial bracing of the rotor  12  achieved in the process does not have to absorb any tolerances in the circumferential direction. 
         [0018]    In a second exemplary embodiment pursuant to  FIG. 3  in which identical components are provided with the identical reference numerals, the snap hooks  16 , in contrast to the first exemplary embodiment, are configured on or fastened to a flange ring  28  formed from the pot  24 . 
         [0019]    In a third exemplary embodiment (see  FIG. 4 ), in which identical components are once again provided with identical reference numerals, the length of the snap hooks  30  and thus the required tolerance compensation is reduced in contrast to the first and second exemplary embodiment. In this case, the laminated core of the stator  12  is configured in a stepped manner in the axial extension thereof, and the latching lugs  32  of the snap hooks  30  engage on a ledge  34  in the assembled state. The ledge  34  is thereby formed by means of the selection of two different sheet metal ring thicknesses. 
         [0020]    The mounting of a stator described above is, of course, not limited to the installation in a coolant pump but can be universally used for electric motors in a variety of applications.