Abstract:
The invention relates to a blower ( 99 ), in particular for an engine cooling blower in a motor vehicle, comprising a N housing ( 10 ) having a cooling air guide device ( 200 ), wherein the housing ( 10 ) is designed for mounting a drive unit ( 102, 103 ) and the cooling air guide device ( 200 ) in the motor vehicle, and for guiding a cooling air flow ( 20, 30, 31, 32 ) to the drive unit ( 102, 103 ), wherein the cooling air guide device ( 200 ) is designed as one piece with the housing ( 10 ).

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The invention relates to a fan unit, particularly for an engine cooling fan in a motor vehicle, exhibiting a housing with a cooling air flow device, wherein the housing is designed to secure a drive unit and the cooling air flow device in the motor vehicle and to direct a cooling air flow at the drive unit. 
         [0002]    Drives with an electric motor are known in the art, said motor exhibiting a housing with a rotor and a stator and a mounting for the rotor. The housing comprises a housing cover which is axially disposed on one side of the housing and closes off a housing interior. DE 10 2006 015 064 A1 proposes in this respect that a fan should be disposed at each front end of the rotor, wherein a cooling channel in the rotor is assigned to each segment of the fan, in order to convey cooling air into the rotor. This involves the air flow passing via several separately mounted components. 
       SUMMARY OF THE INVENTION 
       [0003]    The problem addressed by the invention is that of providing a fan unit with an improved cooling air flow. 
         [0004]    It was recognized in the invention that the cooling air flow in a fan unit can be improved by making the housing integral with a cooling air flow device, which directs a cooling air flow at a drive unit. 
         [0005]    On account of the integral design, as compared with a customary multi-piece embodiment, the housing can be simply and quickly mounted along with the cooling air flow device during assembly of the fan unit. 
         [0006]    In a further embodiment of the invention, the cooling air flow device exhibits at least one cooling fin and a deflecting mechanism, wherein the cooling fin is designed to guide the longitudinal direction of the cooling air flow and the deflecting mechanism is designed to determine the transverse direction of the cooling air flow, wherein the cooling fin is designed integrally with the deflecting mechanism. This has the advantage that there are no gaps between the cooling fin and the deflecting mechanism through which the cooling air can pass, so that leakage losses in the cooling air flow mechanism are reduced. 
         [0007]    In a further embodiment of the invention, the cooling fin exhibits a horizontal cooling fin section, which is inclined in the alignment of its longitudinal axis, in order to provide the cooling air flow with a swirl effect. The advantage of this is that the rotating cooling air flow exhibits a greater cooling effect at the surface of the housing over which the flow passes. 
         [0008]    In a further embodiment of the invention, the cooling fins are disposed at least peripherally on the housing, wherein the deflecting mechanism is disposed in an end section of the cooling fin, in order to direct the cooling air flow at the interior of the housing. The advantage of this is that the cooling air flow passes over a greater radiating surface for the dissipation of heat. 
         [0009]    In a further embodiment of the invention, the housing is produced along with the cooling air flow device by die-casting. The advantage of this is that the housing and the cooling air flow device can be produced together cost-effectively. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The invention is described in greater detail below with the help of drawings. In these: 
           [0011]      FIG. 1  shows a schematic 3D representation of a fan unit for an engine cooling system with a housing according to a first embodiment; 
           [0012]      FIG. 2  shows a schematic 3D view of the housing shown in  FIG. 1 ; 
           [0013]      FIG. 3  shows a top view of a section of the housing shown in  FIG. 2  according to a first embodiment; 
           [0014]      FIG. 4  and  FIG. 5  show sectional views of the sectional planes shown in  FIG. 3 ; 
           [0015]      FIG. 6  shows a top view of a section of the housing shown in  FIG. 2  according to a second embodiment; and 
           [0016]      FIG. 7  shows a side view through the cooling air flow device shown in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0017]      FIG. 1  shows a schematic 3D representation of a fan unit  99  for an engine cooling system with a housing  10  according to a first embodiment. The fan unit  99  comprises an electric motor  100  to drive a cooling fan  140  in a motor vehicle. The electric motor  100  in this case exhibits a stator  102  and a rotor  103  as the drive unit, which is disposed on the rotor shaft  104 . The electric motor  100  has a brushless design as the external rotor. In this case the windings  110  used to generate an alternating magnetic field are disposed on the stator  102 . The magnets  108  moving in the alternating magnetic field are disposed on the inner peripheral surface of a yoke housing  101  of the rotor  103 . In addition, a fan  106  is disposed on the outside of the yoke housing  101 . The fan  106  exhibits fins  118  disposed peripherally and also radially disposed fins  119  on the end face. The cylindrical yoke housing  101  is closed off at one front end by the housing  10 , wherein a control unit  160  may be disposed on the housing  10  opposite the drive unit. In this case, the housing  10  with the control unit  160  may be closed by means of a housing cover  115 . The housing  10  optionally exhibits a multiplicity of cooling studs  9  on a surface  91  of the end face turned towards the electric motor  100 . In addition, several cooling air flow devices  200  are disposed integrally with the housing  10 , ventilating an interior space  113  of the electric motor  100 . On the periphery, the cooling air flow device  200  of the housing  10  is surrounded by a frame  150 , which serves to secure the fan unit  99 . There is a gap  111  between the fan  106  and the frame  150 . 
         [0018]    In order to eliminate the waste heat produced during running from the electric motor  100  and the control unit  160 , the fan  106  is designed to convey cooling air through the housing  10  into the interior space  113  of the electric motor  100 . In this case, the fan  106  is designed to convey the cooling air particularly to temperature-critical points of the drive unit, for example the windings  110  of the stator  102  and the magnets  108 . In order to eliminate heat, the stator  102  has a multiplicity of through-holes  109 , through which the cooling air is conveyed through the stator. In addition, the yoke housing  101  exhibits a multiplicity of openings, through which the cooling air leaves the yoke housing  101 . 
         [0019]    In order to supply the electric motor  100  with cooling air while running, the fan  106  draws in cooling air by creating negative pressure in the interior space  113  through the cooling air flow device  200 . The cooling air flow device  200  deflects the flow direction of the cooling air into an inner area  112  of the electric motor  100 . This involves the cooling air flowing around the cooling studs  9  before it flows in the direction of the windings  110  of the stator  102 . The cooling air passes through the stator  102  via the through-holes  109  and leaves the interior space  113  of the yoke housing  101  via the openings  114  on the front end of the yoke housing  101  and enters the area of the radial fins  119  of the fan  106 . The cooling air is conveyed radially outward by the radial fins  119 , wherein the fins  118  disposed peripherally convey the cooling air to the gap  111 . The fan  106  conveys the heated cooling air through the gap  111  between the fan  106  and the frame  150  out of the electric motor  100 . The creation of negative pressure in the interior space  113  takes place essentially in the area of the fins  119  disposed radially on the front end of the yoke housing  101 . However, other types of design for the fan  106  are also conceivable, axial fans, for example. 
         [0020]      FIG. 2  shows a schematic 3D representation of the housing  10  shown in  FIG. 1 . In this case the same components are identified below using the same reference numbers. A circle is used to mark a section of the housing  10  and of the cooling air flow device  200 , in order to show this in two different embodiments in  FIG. 3  and  FIG. 6 . For a clearer depiction of the cooling air flow device  200 , the remaining components of the electric motor  100  are not shown. 
         [0021]    The housing  10  has a connection  8  for the supply of electricity to the electric motor  100 . The housing  10  is roughly cup-shaped and several cooling air flow devices  200  are disposed on its periphery. The housing  10  optionally exhibits several cooling studs  9  on its end surface, which project from the surface  91  of the housing  10 . Between the individual cooling air flow devices  200 , several first cooling fins  22  are also disposed, which run along at least part of the periphery of the housing  10  and along the surface  91  of the housing  10 , depending on the type of design. 
         [0022]    The cooling air flow device  200  has a multiplicity of second cooling fins  2  and a deflecting mechanism  3 . On the cooling air flow device  200  there is furthermore a fixing opening  6  for the screw-attachment of the housing  10  to the frame  150 . The cooling air flow devices  200  are disposed offset at an angle of roughly 90°. However, they may also be disposed in accordance with another cooling air requirement. The angle offset enables cooling air to flow over large parts of the surface  91  of the housing  10 . 
         [0023]    The fan  106  shown in  FIG. 1  is driven by the rotor  103  and is designed to produce negative pressure in an interior space  113  of the electric motor  100 . Cooling air is thereby drawn via the cooling air flow device  200  and along the first cooling fins  22  into the interior space  113  of the electric motor  100 . In this case, the cooling air flows along the first cooling fins  22  into the yoke housing and straight into one of the external radial areas  116  of the rotor  103  shown in  FIG. 1 , without any significant deflection, so that the magnets  108  are cooled. The cooling air is likewise drawn in by the cooling air flow device  200 , but the cooling air flow is not conveyed by the deflecting mechanism  3  to the rotor  103  without any significant deflection, as in the case of the first cooling fins  22 , but its flow direction is deflected by roughly 50 to 80°, so that the inner areas  112  of the stator  102  are also thereby supplied with cooling air. To increase the area of the surface  91  of the housing  10 , cooling studs  9  are disposed in the area of the cooling air circulation, which project into the cooling air flow, so that a greater amount of heat is thereby released by the heated housing  10  into the cooling air flow. The second cooling fins  2  of the cooling air flow device  200  also run in an area of the front of the surface  91  of the housing  10 . This has the advantage that the deflected cooling air flow continues to be conveyed in its flow direction, in order to penetrate deeper into the inner areas  112  of the electric motor  100  close to the axis  104  of the rotor  103  and avoid creating a swirl effect in the cooling air flow. 
         [0024]    The cooling air flow is usually guided by means of several components, which are disposed on the housing  10 . Apart from the cost involved in assembling individual components, the multi-part design leads to gap losses and swirl effects, which can be avoided if the deflecting mechanism  3  of the cooling air flow device  200  is integral with the second cooling fins  2 . In order to guarantee that the housing  10  has high thermal conductivity, the material used for the housing  10  is aluminum. The housing  10  may, however, exhibit other materials too, such as copper, iron, nickel, magnesium or plastic, in order to influence both the thermal conductivity and also the strength of the housing  10 . The integral design means that the housing  10  can be produced cost-effectively along with the cooling air flow device by means of die-casting, compression-moulding or extrusion. Likewise, assembly of the electric motor  100  to the frame  150  along with the housing  10  is made easier. 
         [0025]      FIG. 3  shows a top view of a section of the housing  10  shown in  FIG. 2 . The figure shows two sectional planes B-B and C-C standing perpendicular to one another. A cooling air flow  31  is thereby drawn in by the fan  106  shown in  FIG. 1  through the cooling air flow device  200 , wherein the cooling air flow  31  is deflected by the deflecting mechanism  3 , so that the cooling air flow  31  passes over the front of the housing  10  and over the cooling studs  9 . Since the second cooling fins  2  run parallel to one another, the cooling air flow  31  is guided through the deflecting mechanism  3  in its flow direction following the deflection, so that a swirl effect is avoided at the deflecting mechanism  3 . The advantage of this is that the flow direction of the cooling air flow  31  can be determined simply and reliably. It would also be conceivable for the second cooling fins  2  to be fanned or inclined at the front end of the housing  10 , in order to distribute the cooling air flow  31  accordingly over the surface  91  of the housing  10 . 
         [0026]      FIG. 4  and  FIG. 5  show sectional views of the sectional planes B-B and C-C shown in  FIG. 3 . In this case,  FIG. 4  shows a cross-section through the housing  10  along the sectional plane B-B and  FIG. 5  shows a longitudinal section through the cooling air flow device  200  along the sectional plane C-C. An incoming cooling air flow  30  is guided in a longitudinal direction by a vertical cooling fin section  40  until the cooling air flow  30  is deflected by the deflecting mechanism  3 , which is disposed in the end section of the cooling fin  2 . The vertical cooling fin section  40  is also designed such that heat is emitted into the cooling air flow  30  as soon as it is sucked into the housing of the electric motor  100 . Following the deflection of the cooling air flow  30  by the deflecting mechanism  3 , the deflected cooling air flow  31  is guided by the horizontal cooling fin axis  42  of the cooling fin part  21  running perpendicular to the surface  91  of the housing  10 . The same alignment of the horizontal cooling fin section  21  and the vertical cooling fin section  40  on one plane, as shown, causes a particularly low-swirl effect in the cooling air flow  30 ,  31 . 
         [0027]      FIG. 6  shows a top view of a section of the housing  90  in accordance with a second embodiment.  FIG. 7  shows a sectional view through a cooling air flow device  201  shown in  FIG. 6  along the sectional plane C-C. In this case, a cooling fin axis  42  of a vertical cooling fin section  40  with a cooling fin  22  is inclined at angle α relative to the surface  91  of the housing  10 . Unlike the embodiment shown in  FIG. 3  to  FIG. 5 , the vertical cooling fin sections  40  are not perpendicular to the surface  91  of the housing  90 . This means that the cooling air is no longer drawn through the cooling air flow device  201  parallel to the rotor axis  104  by the fan  106  in the electric motor  100 , but instead suction takes place in this embodiment inclined at an angle α relative to the housing  10 . 
         [0028]    The horizontal cooling fin sections  21  also correspond in terms of their alignment to the configurations shown in  FIG. 1  to  FIG. 5  of the horizontal cooling fin sections  21 . The incline of the vertical cooling fin sections  40  will provide a cooling air flow  32  with a swirl effect following deflection by the deflecting mechanism  3 , so that a rotating cooling air flow  20  develops a greater cooling effect on the top  91  of the housing  90  or on the cooling studs  9 . The desired rotation of the cooling air flow  32  is thereby defined by the incline of the vertical cooling fin sections  40 . In this case, the rotation of the cooling air flow  32  is increased with a smaller angle α. 
         [0029]    In order to produce the housing  90  by die-casting, the vertical cooling fin sections  40  can only be inclined at an angle α relative to the housing  90  insofar as the semicircular pieces needed for production are able to simulate the geometry of the vertical cooling fin sections. 
         [0030]    The embodiments shown in  FIG. 1  to  FIG. 7  are also suitable, for example, for supplying the brush area of an electric motor with an adequate flow of cooling air. It is also conceivable for further components of a fan unit shown by way of example to be supplied with an adequate flow of cooling air, depending on the application involved.