Abstract:
An electrically commutated DC motor ( 1 ) for a liquid pump ( 2 ) with a pump housing ( 3 ) with a suction connector ( 4 ) and a pressure connector ( 5 ) for connection to a hydraulic circuit, an essentially disk-like pump rotor ( 6 ) mounted to rotate in the pump housing, consisting of an impeller ( 7 ) with several pump vanes and a permanent magnet ( 8 ), a partition ( 11 ) separating a pump space ( 9 ) from a dry space ( 10 ), in which the partition is arranged in an axial gap ( 12 ) between the pump rotor ( 6 ) and several axially aligned wound stator poles ( 14 ) of the DC motor. The present invention configures a DC motor, so that it can be installed simply and reliably, is designed particularly robust and therefore has a very long operating lifetime.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
     The invention concerns an electrically commutated DC motor for a liquid pump with a pump housing with a suction connector and a pressure connector for connection to a hydraulic circuit, an essentially disk-like pump rotor mounted to rotate in the pump housing, consisting of an impeller with several pump vanes and a permanent magnet, and a partition separating a pump space from a dry space, the partition being arranged in an axial gap between the pump rotor and several axially aligned wound stator poles of the DC motor. 
     (2) Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98 
     A generic electronically commutated DC motor for a liquid pump is known from DE 196 46 617 A1. The connections in the known DC motor are only held in a plug cover without special securing measures and are in direct contact with a circuit board. The same circuit board is directly connected to winding connections. This structure is not stable and, under extreme loads and after a longer running time, leads to damage and failures. 
     An object of the present invention is to configure a DC motor, so that it is simple and reliable to install, is designed particularly robust and therefore has a very long lifetime. 
     BRIEF SUMMARY OF THE INVENTION 
     The object is met solved according to the invention in a commutated DC motor for a liquid pump having a pump housing with a suction connector and a pressure connector for connection to a hydraulic circuit. The DC motor comprises a motor shaft; an essentially disk-shaped pump rotor mounted to the motor shaft to rotate in the pump housing, the rotor having of an impeller with several pump vanes and a permanent magnet; a plurality of axially aligned wound stator poles; an axial air gap between the pump rotor and the axially aligned wound stator poles; a partition separating a pump space from a dry space, the partition being arranged in the axial gap; a plurality of insulation elements having moldings, the insulation elements being provided on the poles; a plurality of stator windings each having first and second winding ends, the stator windings being wound on the poles, the first and second winding ends being mechanically fastened to the moldings; a first circuit board mechanically and electrically connected to the first winding ends and arranged in a first plane parallel to the partition, the first circuit board having conductor tracks for interconnection of the first winding ends of the stator windings; a second circuit board mechanically and electrically connected to one part of the second winding ends and provided with a control circuit arranged in a second plane parallel to the partition; and a contact support arranged between the insulation elements and the first circuit board, the contact support having contact receptacles for mechanical fastening of connection contacts. 
     By separation of the individual functional planes, a situation is achieved in which mechanical loads and electronic interferences are kept away from sensitive components and contacts on the equipped circuit board. The plug connections are secured on their own support plate and fixed in the stator, so that mechanical loads can be excellently diverted. The first circuit board is designed very simply and produced, mounted and contacted with known processes. High reliability in the assembly process is therefore guaranteed. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       A practical example of the invention is explained below further below with reference to the drawing. In the drawing: 
         FIG. 1  shows a three-dimensional view of a pump housing, 
         FIG. 2  shows the pump housing from  FIG. 1  with an assembled pump rotor, 
         FIG. 3  shows the arrangement from  FIG. 2  with a mounted partition, 
         FIG. 4  shows the arrangement of  FIG. 3  with mounted wound stator poles, 
         FIG. 5  shows the arrangement from  FIG. 4  with a mounted stator return, 
         FIG. 6  shows the arrangement from  FIG. 5  with the mounted contact support, 
         FIG. 7  shows the arrangement from  FIG. 6  with a mounted circuit board, 
         FIG. 8  shows the arrangement from  FIG. 7  with a mounted heat conducting element, 
         FIG. 9  shows the arrangement from  FIG. 8  with an equipped circuit board, 
         FIG. 10  shows the arrangement from  FIG. 9  with a mounted motor housing, 
         FIG. 11  shows a view of the partition from an opposite perspective, 
         FIG. 12  shows a view of the stator poles from the same perspective, 
         FIGS. 13   a ,  13   b  show views of the heat conducting element, 
         FIGS. 14   a ,  14   b  show views of the circuit board, 
         FIGS. 15   a ,  15   b  show views of the contact support, 
         FIG. 16  shows a view of a stator pole, 
         FIG. 17  shows the stator pole from  FIG. 16  with mounted insulation elements, 
         FIG. 18  shows the arrangement from  FIG. 17  with a winding, 
         FIG. 19  shows the arrangement from  FIG. 18  from another perspective, 
         FIG. 20   a  shows a second variant of the heat conducting element and 
         FIG. 20   b  shows a third variant of the heat conducting element. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In describing preferred embodiments of the present invention illustrated in the drawings, specific terminology is employed for the sake of clarity. However, the invention is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. 
       FIG. 1  shows a three-dimensional view of a pump housing  3 , consisting of plastic material with a suction connector  4 , a pressure connector  5  and screw mounting eyes  36 . 
       FIG. 2  shows the pump housing  3  from  FIG. 1  with a pump rotor  6  mounted in a pump space  9 , which is mounted to rotate on a shaft. The pump rotor  6  consists essentially of a permanent magnet  8  in the form of an alternating magnetized permanent magnet ring connected to an impeller  7 . 
       FIG. 3  shows the arrangement from  FIG. 2  with a mounted partition  11  that separates the pump space from a dry space  10 . The partition  11  also has screw mounting eyes  37  corresponding to the screw mounting eyes  36  of the pump housing  3 . The partition  11  has recesses  13  to accommodate stator poles, especially their pole shoes. The partition is also in one piece with three fastening bushings  30  provided with internal thread  42 , which extend parallel around a motor shaft  41  from the partition plane  11 . 
       FIG. 4  shows the arrangement from  FIG. 3  with six mounted wound stator poles  14  aligned axially and parallel and uniformly distributed around the motor shaft  41 . The stator poles  14  are each enclosed by an insulation element  15  provided with a stator winding  16 . The windings are mechanically fastened to the insulation element  15  and their ends  17 ,  18  extend parallel to motor shaft  41 . First winding ends  17  end in a first plane, whereas second winding ends  18  are designed longer than the first winding ends  17  and end in a second plane. The insulation elements  15  are in one piece with receptacles  21   a ,  21   b  that extend pin-like axially and parallel from the side facing away from the pump. Further description of the stator poles occurs relative to  FIGS. 16 to 19 . 
       FIG. 5  shows the arrangement of  FIG. 4  with a mounted stator return  20 , which consists of a laminated core of several identically designed return sheets. This stator return  20  has fastening devices  29 , consisting of three radial protrusions with disk-like punch-outs that are covered with the inside thread  42  of the fastening bushings  30 . Protrusions are provided on two fastening bushings  30 , in addition to inside thread  42 , which are dimensioned differently and are supposed to prevent incorrect assembly of the stator return  20 . Each pole has a mounting pin  19 , which engages in a correspondingly designed recess of the stator return  20 . The stator return  20  is designed ring-like and runs within the circle described by the receptacles  21   a  and  21   b . The stator return  20  is secured against loosening with the stator poles  14  by a deformation process, like caulking. 
       FIG. 6  shows the arrangement from  FIG. 5  with a mounted contact support  22 , consisting of plastic material. The contact support  22  is in one piece with contact receptacles  43 , mounting pins  23 , openings for the receptacles  21   a  and  21   b  of the insulation elements, openings for the winding end  17  with recesses  45  in the area of the fastening bushings  30 , with a central recess  47  and centering pins  44   a ,  44   b . The mounting pins  23  are designed hollow and accommodate the second winding ends  18 , which, in the assembled state of the contact support, protrude significantly from the hollow mounting pins  23 . The contact supports are shaped so that U-shaped bent contacts can be sealed in them. Part of the U-shaped connection contacts  26  and, on one side, on a first side directed toward the motor shaft, and on the other side in a plug plane, and another part of the U-shaped connection contacts  26  and, on the one side, on a second side facing away from the motor shaft, and on the other side in the plug plane. 
       FIG. 7  shows the arrangement in  FIG. 6  with a mounted circuit board  24 , which is essentially formed with the same passages and recesses as the contact support  22 . In particular, the circuit board  24  has recesses  46  in the area of the fastening bushings  30 , central recess  48  and different openings for the receptacles  21   a ,  21   b  of the insulation elements, for the hollow mounting pins  23  of the contact support and for contact openings for electrical and mechanical connection of the first shorter winding end  17  to the circuit board, especially with soldering eyes that are partially connected to each other via conductor tracks  27 . An opening for the contact receptacles  43  and the centering pins  44   a  is also present. The receptacles  21   a  and  21   b  are shaped according to a heat deformation process, so that the circuit board  24  and the contact support  22  are firmly connected to the six insulation elements in shape-mated fashion, the receptacles  21   a ,  21   b  being deformed in the fashion of rivet heads. 
       FIG. 8  shows the arrangement of  FIG. 7  with a mounted heat conducting element  25 . The heat conducting element  25  consists of aluminum and is provided with recesses for hollow mounting pins  23 , centering pins  44   a  and the contact receptacles  43 . The heat conducting element  25  is also in one piece with spacers  31   a , which engage in recesses  45  of the contact support  22  and recesses  46  of circuit board  24  and extend up to the return  20 . On the side of the heat conducting element opposite the spacers  31   a , additional spacers  31   b  are provided, which serve to accommodate an additional circuit board. The heat conducting element consists of a first essentially disk-like area and a second essentially hollow cylindrical area, which is centrally connected to the disk-like area and extends over the central recess  48  of the circuit board  24  and the central recess  47  of contact support and a central recess of the stator return up to the partition  11 . 
       FIG. 9  shows the arrangement from  FIG. 8  with an equipped circuit board  28 . The circuit board  28  has contact openings for passage of the winding ends  18 , which are electrically and mechanically connected at soldering eyes to circuit board  28 . This circuit board  28  also has an opening for the contact receptacles  43 . The circuit board  28  lies axially against the spacers  31   b  and radially against the centering pins  44   a ,  44   b  and is screwed to the fastening bushings  30  with screws  49 , so that they also fasten heat conducting element  25  and the stator return, in addition to the circuit board  28 . 
       FIG. 10  shows the arrangement from  FIG. 9  with mounted motor housing  50 , which is in one piece with a plug housing  51 , into which a plug  52  is inserted. The motor housing is also in one piece with screw fastening eyes  38 , in which these coincide with the screw fastening eyes  37  of partition  11  and the screw fastening eyes  36  of the pump housing. 
       FIG. 11  shows a view from the opposite perspective of the partition  11  with the motor housing connected to it. The partition  11  and the motor housing delimit the dry space, in which the stator of the DC motor is situated. The partition  11  is in one piece with a bearing mount  53  to accommodate an axial bearing to support the pump rotor. 
       FIG. 12  shows a view from the same perspective of the stator poles  14 , with the insulation elements  15 , windings  16  and the hollow cylindrical area of the heat conducting element  25 . 
       FIGS. 13   a ,  13   b  show views of the heating conducting element  25  with an opening  55   a  for the centering pins  44   a , three openings  56   a  for the mounting pins  23  of the contact support, a plug recess  33 , spacers  31   a  and  31   b  and a hollow cylindrical area  54  arranged centrally on the heat conducting element. 
     In  FIG. 13   b , large recesses  57  and small recesses  58  are also provided for the soldering sites and rivet heads. 
       FIGS. 14   a ,  14   b  show views of the circuit board  24  with conductor tracks  27 , openings  59   a  for internal mounting of the insulation element, openings  59   b  for outer mounting of the insulation element, central recess  48 , opening  55   b  for the centering pins  44   a , openings  56   b  for the mounting pins  23  of the contact support, recesses  46  for the spacers of the heat conducting element, a plug recess  34  and additional openings for the winding ends. 
       FIGS. 15   a ,  15   b  show views of the contact support  22  with centering pins  44   a ,  44   b , the hollow mounting pins  23 , the contact receptacles  43  that are in one piece with the contact support, recesses  45  for the spacer of the heating conducting element, the central recess for accommodating the cylindrical part of the heat conducting element, openings  60   a  for the internal receptacles of the insulation elements, openings  60   b  for the external receptacles of the insulation elements and openings for the winding wire ends. Inner centering devices  61   a , outer centering devices  61   b  for mounting on the stator return and joining aids  62 , designed essentially conical, in order to be able to join the winding ends more simply during assembly of the contact support, are also shown in  FIG. 15   b.    
       FIG. 16  shows a view of a stator pole  14 , comprising a mounting hole  19  for connection to the stator return and a pole shoe  63 , having a roughly circular segment-like cross-sectional surface. The stator pole  14  in the present practical example consists of a magnetically conducting material pressed and sintered from the powder form. 
       FIG. 17  show the stator pole from  FIG. 16  with the mounted insulation element  15 , with the contact flange  67 , a collar  35 , grooves  64  in the base of the insulation element, which serve to achieve regular arrangement of the winding wires, a wire guide  65 , in order to bring the wire ends in defined fashion against molding  66  after the winding process, and then to wind around the corresponding fastening devices, in which one winding is sufficient. After production of the winding, both winding ends  17  are aligned axial and parallel to the pole axis, and later also the motor axis. The insulation element also has receptacles  39  and  40  to accommodate the stator return  20 . The inner pin-like receptacle  21   a  and the outer pin-like receptacle  21   b  are connected to the receptacles  39  and  40 . Both are aligned axial and parallel. 
       FIG. 18  shows the arrangement from  FIG. 17  wound with a winding  16 . It is readily apparent here how the wire guide is positioned with the winding wire and how the winding wire end is wound around the fastening device. 
       FIG. 19  shows the arrangement from  FIG. 18  from another perspective. It is readily apparent here that the pole has a polygonal cross section  12 . This primarily serves to prevent rotation and finally also for better utilization of space. 
       FIG. 20   a  shows a second variant of the heat conducting element  25 , in which the disk-like area  69  is provided centrally with a central opening  72  and the hollow cylindrical area  54  is closed by a bottom  70  on its side facing the pump impeller. Through this embodiment, the possibility is obtained of accommodating a capacitor  68  arranged on circuit board  28  in space-saving fashion in a mounting space  74  of the heat conducting element  25 . 
       FIG. 20   b  shows a third variant of the heat conducting element  25 , in which the hollow cylindrical area  54  is open on both sides, but a partition  71  is provided in its center area, which separates the dry space from the wet space. In this variant, the partition  11  (not shown here) is also perforated, so that an additional wet space  75  extends to partition  71 . The third variant combines the first two variants of the heat conducting element  25  with each other. In the first place, an installation space for the capacitor  68  is present and, in the second place, part of the hollow cylindrical area  54  can also be used as a cooling channel. On the end of the hollow cylindrical area  54 , there is a receiving space  73  for a bearing. 
     Modifications and variations of the above-described embodiments of the present invention are possible, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims and their equivalents, the invention may be practiced otherwise than as specifically disclosed. 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 LIST OF REFERENCE NUMBERS 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                  1 
                 DC motor 
               
               
                   
                  2 
                 Liquid pump 
               
               
                   
                  3 
                 Pump housing 
               
               
                   
                  4 
                 Suction connector 
               
               
                   
                  5 
                 Pressure connector 
               
               
                   
                  6 
                 Pump rotor 
               
               
                   
                  7 
                 Pump impeller 
               
               
                   
                  8 
                 Permanent magnet 
               
               
                   
                  9 
                 Pump space 
               
               
                   
                 10 
                 Dry space 
               
               
                   
                 11 
                 Partition 
               
               
                   
                 12 
                 Polygonal cross section 
               
               
                   
                 13 
                 Recesses 
               
               
                   
                 14 
                 Stator pole 
               
               
                   
                 15 
                 Insulation element 
               
               
                   
                 16 
                 Stator winding 
               
               
                   
                 17 
                 First winding end 
               
               
                   
                 18 
                 Second winding end 
               
               
                   
                 19 
                 Mounting pin 
               
               
                   
                 20 
                 Stator return 
               
               
                   
                 21a 
                 Receptacle 
               
               
                   
                 21b 
                 Receptacle 
               
               
                   
                 22 
                 Contact support 
               
               
                   
                 23 
                 Hollow mounting pin 
               
               
                   
                 24 
                 First circuit board 
               
               
                   
                 25 
                 Heat conducting element 
               
               
                   
                 26 
                 Connection contact 
               
               
                   
                 27 
                 Circuit 
               
               
                   
                 28 
                 Conductor track 
               
               
                   
                 29 
                 Equipped circuit board 
               
               
                   
                 30 
                 Fastening device 
               
               
                   
                 31 
                 Fastening bushing 
               
               
                   
                 31a 
                 Spacer 
               
               
                   
                 31b 
                 Spacer 
               
               
                   
                 33 
                 Plug recess 
               
               
                   
                 34 
                 Plug recess 
               
               
                   
                 35 
                 Collar 
               
               
                   
                 36 
                 Screw connection eye 
               
               
                   
                 37 
                 Screw connection eye 
               
               
                   
                 38 
                 Screw connection eye 
               
               
                   
                 39 
                 Receptacles for return 
               
               
                   
                 40 
                 Receptacles for return 
               
               
                   
                 41 
                 Motor shaft 
               
               
                   
                 42 
                 Internal thread 
               
               
                   
                 43 
                 Contact receptacle 
               
               
                   
                 44a 
                 Centering pin 
               
               
                   
                 44b 
                 Centering pin 
               
               
                   
                 45 
                 Recesses in contact support 
               
               
                   
                 46 
                 Recesses in circuit board 
               
               
                   
                 47 
                 Central recess in support 
               
               
                   
                 48 
                 Central recess in circuit board 
               
               
                   
                 49 
                 Screw 
               
               
                   
                 50 
                 Motor housing 
               
               
                   
                 51 
                 Plug housing 
               
               
                   
                 52 
                 Plug 
               
               
                   
                 53 
                 Bearing mount 
               
               
                   
                 54 
                 Hollow cylindrical area 
               
               
                   
                 55a 
                 Opening for centering pin 
               
               
                   
                 55b 
                 Opening for centering pin 
               
               
                   
                 56a 
                 Opening for mounting pin 
               
               
                   
                 56b 
                 Opening for mounting pin 
               
               
                   
                 57 
                 Large recess 
               
               
                   
                 58 
                 Small recesses 
               
               
                   
                 59a 
                 Opening for receptacle inside 
               
               
                   
                 59b 
                 Opening for receptacle outside 
               
               
                   
                 60a 
                 Opening for receptacle inside 
               
               
                   
                 60b 
                 Opening or receptacle outside 
               
               
                   
                 61a 
                 Internal centering device 
               
               
                   
                 61b 
                 External centering device 
               
               
                   
                 62 
                 Joining aid 
               
               
                   
                 63 
                 Pole shoe 
               
               
                   
                 64 
                 Groove 
               
               
                   
                 65 
                 Wire guide 
               
               
                   
                 66 
                 Moldings 
               
               
                   
                 67 
                 Contact flange 
               
               
                   
                 68 
                 Capacitor 
               
               
                   
                 69 
                 Disk-like area 
               
               
                   
                 70 
                 Bottom 
               
               
                   
                 71 
                 Partition 
               
               
                   
                 72 
                 Central opening 
               
               
                   
                 73 
                 Receiving space for bearing 
               
               
                   
                 74 
                 Receiving space for capacitor 
               
               
                   
                 75 
                 Additional wet space