Abstract:
A centrifugal pump motor comprising a permanent magnet rotor, a wound stator that is separated from the permanent magnet rotor by means of a containment shell, a circuit board having a large electronic component electrically connected to it, and a motor housing with a plug connection. The centrifugal pump motor provides a robust design for a generic centrifugal pump motor, so as to prevent damage during installation and operation, as well as additionally ensuring a space-saving and compact arrangement of the electronic components, in order to enable optimal heat dissipation of the electronic components. Furthermore, a simple way of manufacturing is provided.

Description:
BACKGROUND OF THE INVENTION 
     (1) Field of the Invention 
       [0001]    The invention relates to a centrifugal pump motor comprising a permanent magnet rotor, a wound stator that is separated from the permanent magnet rotor by means of a containment shell, a circuit board having a large electronic component electrically connected to it, and a motor housing with a plug connection. The large electronic component can be a round or non-round component having a diameter and/or a thickness/width that is many times bigger than the circuit board thickness. Likewise, more than one large component can be connected to the circuit board. 
       (2) Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 1.98 
       [0002]    In combustion engines in the field of motor vehicles, mechanical centrifugal pumps driven by the crankshaft via a gear belt are generally provided as the main cooling water pump. As a support or an alternative in a shut-off combustion engine, electric ancillary cooling water pumps are used, which are generally designed as electronically commutated direct-current motors. Main cooling water pumps can also be electrically driven. Due to constricted installation conditions, high thermal stresses as well as the use inside the engine compartment, particularly high requirements must be met regarding robustness, heat dissipation characteristics and a compact installation space utilization. Likewise, cooling water pumps are used with hybrid vehicles and electric vehicles. In the latter, they are used predominantly in the cooling circuit of a battery cooling system. Usually, with electronically commutated direct-current motors, circuit boards with a plurality of electronic components are required, which often results in difficulties of finding enough space to fit them on a limited circuit board surface. Furthermore, often plug-in connectors are provided that have to absorb significant forces during the installation of a mating plug, which, in the case of plug-in contacts that are mechanically and electrically fixed directly on a circuit board, can result in damage. 
       BRIEF SUMMARY OF THE INVENTION 
       [0003]    Thus, the invention seeks to solve the problem of providing a robust design for a centrifugal pump motor, so as to prevent damage during installation and operation, as well as additionally ensuring a space-saving and compact arrangement of the electronic components, in order to enable optimal heat dissipation of the electronic components. Furthermore, a simple way of manufacturing is to be ensured. 
         [0004]    By arranging large electronic components in a second plane, the circuit board surface underneath the said components can be utilized for smaller SMD components. This allows the possibility of extremely compact circuitry. Receiving theses components on the support plate makes it possible to exert a pressure force onto these components and to clamp them between the motor housing and the support plate. This favors the heat transfer and a compact design with few hollow spaces. Furthermore, the electrical contacts on the circuit board are not damaged by this. 
         [0005]    A particularly advantageous refinement consists in providing a limit stop for at least one contact element, which contact element must receive mounting forces. In a further refinement of this idea, the contact element has two angled portions, whereby one section between the two angled portions abuts against the limit stop, or is adapted to abut against the limit stop when force is exerted onto the contact element, particularly during assembly of a mating plug. The limit stop absorbs the mechanical forces, so that no damage can be inflicted on the electrical connection between the contact element and the circuit board. 
         [0006]    A further key aspect of the invention is reflected in the fact that the support plate between the circuit board and the motor housing is held without any play. This precludes any vibration-induced damage during operation and enhances the compactness of the structure. The support plate and the circuit board are held without play between the stator and the motor housing. Thus, the circuit board is also mounted in a vibration-proof and compact manner respectively. For this purpose, the stator is provided with an insulating element that directly abuts against the circuit board in the direction parallel to the axis. 
         [0007]    Preferably, this insulating element abuts against the edge region of the circuit board at least in three points. This results in defined conditions by forming a three-point support and excludes any tolerance-related vibration sources that might surface due to undefined gap distances between the joining partners. 
         [0008]    A particularly preferred refinement of the invention provides for the insulating element to be welded to the motor housing. This enables the support plate and the circuit board to be permanently fixed in the intermediate position taken during assembly. 
         [0009]    Preferably, the support plate has several protrusions abutting against the insulating element, which protrusions define the distance between the stator and the support plate as well as the circuit board. For a radial limitation of the installation space for the circuit board, several receiving elements are provided on the support plate. In addition, the radial installation space for the insulating element is also limited by the receiving elements. 
         [0010]    The support plate ( 10 ) fulfills a centering function for the circuit board ( 5 ), which centering function can be provided in particular by means of receiving elements ( 17 ) and/or scraper ribs ( 61 ). In this way, the circuit board is held and clamped. 
         [0011]    For stiffening purposes of the support plate, an at least partly circumferential collar is integrally formed at the edge of a base plate. Moreover, stiffening ramps are provided, which cause a radial stiffening of the collar. 
         [0012]    For optimal heat dissipation and secure mechanical connection of the electronic component, the receiving geometries are integrally formed with the support plate, which receiving geometries are preferably adapted to the geometry of the electronic component. 
         [0013]    In order to be able to construct as compactly as possible, a recess is provided for the electronic component, which recess allows the electronic component to sink deeper into the support plate. Thus, the axial space requirement is minimized. 
         [0014]    A particularly effective heat dissipation via the motor housing is favored by the fact that the motor housing features a bulge in its bottom area, which bulge is adapted to the electronic component. In order to enhance the heat transfer, a heat conduction agent, in particular, a thermally conductive paste, can be incorporated between the electronic component and the bulge. By means of the mechanical pressure that can be exerted due to the sandwich-like structure, the heat conduction agent can be pressed into all remaining gaps. 
         [0015]    Both one electronic component and also multiple electronic components can be fitted onto the support plate and held by respective receiving geometries. Preferably, at least one electrolytic capacitor and one inductor are provided. As the electrolytic capacitor usually has a bigger diameter, the corresponding bulge in the bottom part of the motor housing and the receiving geometry on the support plate have bigger dimensions respectively. 
         [0016]    A second solution for the problem is proposed by the method claim that features the following assembly order: a) providing a motor housing; b) providing a pre-assembled unit comprising the stator, the circuit board and the support plate; c) inserting the pre-assembled unit into the motor housing; d) holding down the assembly and welding an insulating element of the stator onto the motor housing, thereby exerting a force; e) assembling the containment shell and the permanent magnet rotor; and f) assembling the pump head. 
         [0017]    In a refinement of this method, it is proposed for the welding of the insulating element to the motor housing to be performed via laser transmission welding. This is a proven method for connecting plastic materials. For this purpose, the housing material consists a material that is transparent for laser light, while the insulating element consists of material that absorbs this laser light. One insulating element is welded onto the motor housing in three welding regions. Another insulating element is welded to the motor housing with a largely continuous weld seam. The three welding regions are connected to the insulating element in a resilient manner, thus providing a possibility for length compensation. The insulating element that is arranged close to the circuit board is designed to receive a bigger axial force and is therefore welded over a larger circumferential region or over the full circumference. 
         [0018]    In the region of the weld connection, the outer diameter of the insulating element is bigger than the inner diameter of the motor housing. This results in a press fit between the motor housing and the insulating element. A laser beam that is directed from the outside onto the motor housing penetrates it and strikes the welding region of the insulating element in only slightly weakened condition, where it is largely absorbed and thus heats the welding region and the adjoining motor housing, until the plastic material melts. Due to the press fit, the motor housing and the insulating element move slightly towards each other in the welding region and form a very close connection. In order to create a good weld connection, the whole region where the welding partners abut against each other must be heated. For this purpose, the width of the welding region is adapted to the diameter of the laser beam. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0019]    The invention is better understood by reading the following Detailed Description of the Preferred Embodiments with reference to the accompanying drawing figures, in which like reference numerals refer to like elements throughout, and in which: 
           [0020]      FIG. 1 , a sectional view of the centrifugal pump motor according to the invention, 
           [0021]      FIG. 2 , an enlarged section A of  FIG. 1 , 
           [0022]      FIG. 3 , a front view of a support plate, 
           [0023]      FIG. 4 , a first section A-A through  FIG. 3 , 
           [0024]      FIG. 5 , a second section B-B through  FIG. 3 , 
           [0025]      FIG. 6 , a top view of the support plate, 
           [0026]      FIG. 7 , a back view of the support plate, 
           [0027]      FIG. 8 , a three-dimensional representation of the centrifugal pump motor, 
           [0028]      FIG. 9 , a front view of an alternative support plate, 
           [0029]      FIG. 10 , a three-dimensional representation of the alternative support plate, 
           [0030]      FIG. 11 , a side view of the alternative support plate and 
           [0031]      FIG. 12 , a top view of an alternative support plate. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0032]    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. 
         [0033]      FIG. 1  shows a sectional view of a centrifugal pump motor  1  according to the invention, having a wound stator  4 , a permanent magnet rotor  2 , a containment shell  3 , a pump head  22 , a circuit board  5 , a support plate  10  and a motor housing  8 . The stator  4 , the circuit board  5  and the support plate  10  are positioned in a dry space  25 . The permanent magnet rotor  2  is pivot-mounted in a wet space  26  about an axis  27 , which is, on the one hand, fixed in the containment shell  3 , and on the other hand, in the pump head  22 . The containment shell  3  is provided with a containment shell flange  47 , and the pump head  22  is provided with a pump head flange  48 . The motor housing  8  is formed in a pot-shaped manner and is provided with a housing flange  28  and a connector chamber  29 . The pump head flange  48  and the containment shell flange  47  as well as the housing flange  28  are provided with screw holes  49 , with screws  51 , which serve the purpose of screwing the pump head  22  and the containment shell  3  onto the motor housing  8 . On both sides of the containment shell flange  47 , O-rings  54  are arranged as sealing elements. The circuit board  5  is equipped with a plurality of SMD components. Larger components like an electrolytic capacitor  6  and an inductor  7  are held mechanically on the support plate  10 , but are contacted electrically on the circuit board  5 . 
         [0034]    The circuit board  5  and the support plate  10  are axially fixed between the stator  4  and the motor housing  8 . The circuit board  5  is axially and radially fixed between the stator  4  and the support plate  10 . In the support plate  10 , a contact element  12  is mechanically received, which contact element is also electrically connected to the circuit board  5 . A bottom  30  of the pot-shaped motor housing  8  is provided with a bulge  21 , which is adapted to the shape of the electrolytic capacitor  6 . Between the electrolytic capacitor  6  and the bulge  21 , a heat conduction agent  31  is incorporated. Further, a pump impeller  52  that is integrally formed with a hollow shaft  53  are shown in  FIG. 1 . The pump impeller  52  is provided with a cover disc  55 . The permanent magnet rotor  2 , along with the pump impeller  52 , is rotatably mounted via a first fixed bearing  56  and a second spherical bearing  57  on the axis  27  and between the pump head  22  and the containment shell  3 . The fixed bearing  56  is arranged between the axis  27  and a plastic-bonded ring magnet  58  that is molded around the hollow shaft  53 , and bears the pump impeller  52  radially as well as axially via the end of the hollow shaft  53  and a stop disc  20 , which abuts against a fastening sleeve  59  that is integrally formed with the containment shell  3  (see  FIG. 2 ). 
         [0035]      FIG. 2  shows an enlarged section A from  FIG. 1 , with the stator  4 , the motor housing  8 , the circuit board  5 , the support plate  10 , the inductor  7  that is received within a receiving geometry  19 , the connector chamber  29 , the contact element  12 , the containment shell  3  and the permanent magnet rotor  2 . The stator  4  consists of a laminated core  32 , an insulating element  15  and a winding  33 . A protruding region  34  of the insulating element  15  abuts against the edge region of the circuit board  5  in three places. A receiving element  17  of the support plate  10  radially limits the installation space of the insulating element  15  in the area of the protruding region  34 . In a similar way, the installation space of the circuit board  5  is radially limited by the receiving element  17  of the support plate  10 . The contact element  12  is held in a positive-locking manner between a limit stop  11  of the support plate  10  and a housing protrusion  35  in the bottom  30  of the motor housing in axial direction. In addition to that, the contact element  12  is also held in radial direction between the housing protrusion  35  and a radial boundary  36  of the support plate  10 . 
         [0036]    The contact element  12  is provided with angled portions  13 . A region  14  between the angled portions  13  abuts on the one hand against the limit stop  11  and, on the other hand, against the housing protrusion  35 . The contact element  12  is received within a contact channel  44 , which enables the connection with the circuit board  5 . The containment shell  3  is provided in its wet space with cooling pins  64 , and in its dry side with recesses  65 , which can be filled with a heat conduction agent  31 , e.g. a heat conducting paste. The motor housing  8 , the insulating element  15 , the support plate  10 , the containment shell  3  and the pump head  22  consist of a material that can be processed via injection molding. Furthermore, the housing material consists of material that is transparent for laser light, while the insulating element  15  consists of material that absorbs this laser light. The insulating element  15  is welded onto the motor housing via three welding areas or regions  37  by means of a laser transmission welding method. For this purpose, the outer diameter of the insulating element  15  is bigger than the interior diameter of the motor housing  8  in the welding region  37 . This results in a press fit between the motor housing  8  and the insulating element  15 . 
         [0037]    A laser beam that is directed from the outside onto the motor housing  8  penetrates it and strikes the welding region  37  of the insulating element  15  in only slightly weakened condition, where it is largely absorbed and thus heats the welding region  37  and the adjoining motor housing  8 , until the plastic material melts. Due to the press fit, the motor housing  8  and the insulating element  15  move slightly towards each other in the welding region  37  and form a very close connection. In order to create a good weld connection, the whole region where the welding partners abut against each other must be heated. For this purpose, the width of the welding region  37  is adapted to the diameter of the laser beam. Furthermore, the fastening sleeve  59 , the stop disc  20  and the ring magnet  58  can be seen. 
         [0038]      FIG. 3  shows the support plate  10  with its component side. At the edge, the support plate  10  is provided with a collar  18  that is joined by stiffening ramps  38 , which are directed radially inward and stiffen a base plate  39 . From the base plate  39 , receiving geometries  19  protrude, which geometries are largely adapted to the components that are to be assembled. Inside the receiving geometries  19 , recesses  40  are provided, which enable a slight sinking of the components to be assembled, thus saving installation space. Furthermore, several feedthroughs  41  and add-ons  42  to the recess  40  in the base plate  39  are provided, through which connection wires of the components to be assembled can be led. The add-ons  42  serve the purpose of leading the connection wires of an inductor  7  through them, which is why they are arranged on opposite sides of the recess  40 . The limit stop  11  is arranged on a protruding plateau  43  and is designed to receive mounting forces of the contact element  12  (see  FIGS. 1 and 2 ). Here, the three contact elements are provided, which are mounted in different misalignment directions (misalignment between plug contact position and circuit board contact position). On the outer edge of the support plate  10 , three indentations  45  are formed that engage with respective counter-contours of the motor housing  8  (longitudinal ribs), thus ensuring security against rotation of the support plate  10 . 
         [0039]      FIG. 4  shows a first section A-A through the support plate  10 , along with the base plate  39 , the receiving elements  19 , the feedthroughs  40 , the collar  18 , the protrusions  16 , the receiving elements  17 , the limit stop  11 , a contact channel  44 , in which a contact element  12  can be mounted. The protrusions  16  serve as butting surface for the circuit board  5 . The receiving element  17  limits the receiving space for the circuit board  5  in radial direction. A supporting pin  46  arranged approximately in the center of the support plate  10  serves as additional butting region on the circuit board  5 . This supporting pin  46  prevents the circuit board from bending during assembly from the pressure of a heat conduction agent. The recess  45  is provided in the region of the projection  16  and the receiving element  17 . The circuit board  5  is also provided with recesses in which the receiving elements  17  engage. This also serves to ensure that the circuit board  5  is secured against rotation. Tool recesses  60  along the edge of the support plate  10  allow for an assembly tool to be put through for supporting the circuit board  5 . Furthermore, scraper ribs  61  are shown, which scraper ribs serve the purpose of receiving the circuit board. These scraper ribs  61  are dimensioned in such a way that they give in, or can be scraped back, if the circuit board  5  is oversized, so that a connection without play is achieved. 
         [0040]      FIG. 5  shows a section B-B through the support plate  10 , along with the base plate  39 , the receiving elements  19 , the recesses  40 , the collar  18 , the protrusions  16 , the receiving elements  17 , the scrape ribs  61  and the supporting pin  46 . 
         [0041]      FIG. 6  shows a top view of the support plate  10  with a receiving element  19 , the collar  18 , the protrusions  16 , the receiving elements  17 , one scraper rib  61 , the recesses  45  and the supporting pin  46 . 
         [0042]      FIG. 7  shows a back view of the support plate  10 , with the base plate  39 , the recesses  40 , the feedthroughs  41 , the add-ons  42 , the protrusions  16 , the receiving elements  17 , the scraper ribs  61 , the recesses  45 , the tool recesses  60 , the contact channels  44  for receiving the contact elements  12  and the supporting pin  46 . 
         [0043]      FIG. 8  shows a three-dimensional representation of the centrifugal pump motor  1 , with the pump head  22 , with suction port  23  and pressure port  24  and a pump head flange  48 , a containment shell flange  47  that is integrally formed with the containment shell  3 , the motor housing  8 , with the housing flange  28 , the bottom  30 , the connector chamber  29  and the bulge  21  for receiving an electrolytic capacitor  6 . Further, screw holes  49  can be seen, which are formed as add-ons in the pump head flange  48 , the containment shell flange  47  and the housing flange  28 , and enable screw connections. On the motor housing  8 , an axial securing shape  50  is formed, which serves the purpose of axially securing a ring-shaped attachment system arranged around the motor housing  8 . 
         [0044]      FIG. 9  shows a front view of an alternative support plate  10   a  with its component side. At the edge, the support plate  10   a  is provided with a collar  18   a  that is joined by stiffening ramps  38   a,  which are directed radially inward and stiffen a base plate  39   a.  From the base plate  39   a,  receiving geometries  19   a  protrude, which geometries are largely adapted to the components that are to be assembled. Inside the receiving geometries  19   a,  recesses  40   a  are provided, which enable a slight sinking of the components to be assembled, thus saving installation space. Furthermore, several feedthroughs  41   a  and add-ons  42   a  to one of the recesses  40   a  in the base plate  39   a  are provided, through which connection wires of the components to be assembled can be led. The add-ons  42   a  serve the purpose of leading the connection wires of an inductor through them, which is why they are arranged on opposite sides of the recess  40   a.    
         [0045]    The limit stop  11   a  is arranged on a protruding plateau  43   a  and is designed to receive mounting forces. Here, three contact elements  12  can be received, which can be mounted in different misalignment directions (misalignment between plug contact position and circuit board contact position). On the outer edge of the support plate  10   a,  three indentations  45   a  are formed that engage with respective counter-contours of the motor housing (longitudinal ribs), thus ensuring security against rotation of the support plate  10   a.  A stiffening wall  62   a  enhances the bending strength of the support plate  10   a.  The difference with respect to the first embodiment lies in the fact that the support plate  10   a  has a base form that resembles a D. Thus, areas of the support plate  10   a  that are not used are left out. This makes the required injection molding tool simpler and reduces shrinkage problems associated with the injection molding process. 
         [0046]      FIG. 10  shows a three-dimensional representation of the alternative support plate  10   a,  with the collar  18   a,  the base plate  39   a,  stiffening ramps  38   a  between the collar  18   a  and the base plate  39   a,  the receiving geometries  19   a  for an electrolytic capacitor on the one hand and an inductor on the other hand, joining aids  63   a  with cone-shaped chamfers for easier insertion of the electrolytic capacitor, the tool recesses  60   a,  protrusions  16   a,  receiving elements  17   a,  the plateau  43   a  and the recesses  45   a.    
         [0047]      FIG. 11  shows a side view of the alternative support plate  10   a,  with the collar  18   a,  the protrusions  16   a,  the receiving elements  17   a,  scraper ribs  61  on the receiving elements  17   a,  which have a tapering, the recesses  45   a  and the supporting pin  46   a.    
         [0048]      FIG. 12  shows a top view onto the alternative support plate  10   a,  with the collar  18   a,  the receiving geometries  19   a,  the protrusions  16   a,  the receiving elements  17   a,  the scraper ribs  61   a,  the recesses  45   a,  the tool recesses  60   a  and the supporting pin  46   a.    
         [0049]    It is to be understood that the present invention is not limited to the illustrated embodiments described herein. Various types and styles of user interfaces may be used in accordance with the present invention without limitation. 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 described. 
       LIST OF REFERENCE SYMBOLS: 
       [0050]      
         [0000]    
       
         
               
               
             
           
               
                   
               
             
             
               
                 1 
                 Centrifugal pump motor 
               
               
                 2 
                 Permanent magnet rotor 
               
               
                 3 
                 Containment shell 
               
               
                 4 
                 Stator 
               
               
                 5 
                 Circuit board 
               
               
                 6 
                 Electrolytic capacitor 
               
               
                 7 
                 Inductor 
               
               
                 8 
                 Motor housing 
               
               
                 9 
                 Plug connection 
               
               
                 10 
                 Support plate 
               
               
                 11 
                 Limit stop 
               
               
                 12 
                 Contact element 
               
               
                 13 
                 Angled portion 
               
               
                 14 
                 Section 
               
               
                 15 
                 Insulating element 
               
               
                 16 
                 Protrusion 
               
               
                 17 
                 Receiving element 
               
               
                 18 
                 Collar 
               
               
                 19 
                 Receiving geometry 
               
               
                 20 
                 Stop disc 
               
               
                 21 
                 Bulge 
               
               
                 22 
                 Pump head 
               
               
                 23 
                 Suction port 
               
               
                 24 
                 Pressure port 
               
               
                 25 
                 Dry space 
               
               
                 26 
                 Wet space 
               
               
                 27 
                 Axis 
               
               
                 28 
                 Housing flange 
               
               
                 29 
                 Connector chamber 
               
               
                 30 
                 Bottom 
               
               
                 31. 
                 Heat conduction agent 
               
               
                 32 
                 Laminated core 
               
               
                 33 
                 Winding 
               
               
                 34 
                 Protruding region 
               
               
                 35 
                 Housing protrusion 
               
               
                 36 
                 Radial boundary 
               
               
                 37 
                 Welding region 
               
               
                 38 
                 Stiffening ramp 
               
               
                 39 
                 Base plate 
               
               
                 40 
                 Recess 
               
               
                 41 
                 Feedthrough 
               
               
                 42 
                 Add-on 
               
               
                 43 
                 Plateau 
               
               
                 44 
                 Contact channel 
               
               
                 45 
                 Recess 
               
               
                 46 
                 Supporting pin 
               
               
                 47 
                 Containment shell flange 
               
               
                 48 
                 Pump head flange 
               
               
                 49 
                 Screw hole 
               
               
                 50 
                 Axial supporting shape 
               
               
                 51 
                 Screw 
               
               
                 52 
                 Pump impeller 
               
               
                 53 
                 Hollow shaft 
               
               
                 54 
                 O-Ring 
               
               
                 55 
                 Cover disc 
               
               
                 56 
                 Fixed bearing 
               
               
                 57 
                 Spherical bearing 
               
               
                 58 
                 Ring magnet 
               
               
                 59 
                 Fastening sleeve 
               
               
                 60 
                 Tool recess 
               
               
                 61 
                 Scraper rib 
               
               
                 62 
                 Stiffening wall 
               
               
                 63 
                 Joining aid 
               
               
                 64 
                 Cooling pins 
               
               
                 65 
                 Recess