Abstract:
A claw pole rotor with at least one motor module is indicated, the claw pole rotor having a stator ( 11 ) and an external rotor ( 12 ). Stator ( 11 ) and rotor ( 12 ) are configured conical in shape to achieve cost and installation space advantages with the preferred use of the claw pole motor in a fan for a blower for an air conditioning system.

Description:
BACKGROUND INFORMATION  
       [0001]     The invention is based on a claw pole motor according to the definition of the species in claim  1 .  
         [0002]     A known, four-pole claw pole motor of this type designed as an outer rotor motor (Günter Kastinger: “Beiträge zu Ringspulenkleinantrieben”, Diss. May 2001, Johannes Kepler Universität Linz, page 8) has a hollow-cylindrical stator that is concentrically surrounded by a cylindrical rotor with an annular air gap between the two. The rotor is composed of a permanent-magnet ring magnetized in the radial direction and an iron ring serving as magnetic flux return. The stator has a cylindrical ring coil that is wound on a coil shell having an I-shaped cross section. The coil shell is slid onto a sleeve and clamped between two yokes that are pressed onto the sleeve. Two claws extend outwardly from each yoke over the ring coil, whereby the four claws, in total, interlock. The concentric ring coil mounted in the center generates a flux that creates the field in all four claws, so that a total of two pole pairs is formed. Starting at the inner sleeve, the coil flux travels across the claw poles, the air gap and the permanent magnets to the outer magnetic flux return ring. In this ring, the flux continues to flow tangentially and reconnects with the starting point via the geometrically staggered adjacent claws. In the sleeve, the flux lines flow in the direction of the longitudinal axis.  
       ADVANTAGES OF THE INVENTION  
       [0003]     The claw pole motor according to the invention having the features of claim  1  has the advantage that it can be integrated very well into the interior of a device to be driven, in particular a fan wheel of a fan or blower, and therefore requires no additional installation space. Due to its conical form, it may be advantageously slid axially into the device and easily mounted on said device with its rotor, so that a separate rotor shaft can be eliminated and an axially compact design is attainable. When the claw pole motor is used, in particular, to drive the fan wheel of a fan, e.g., in a blower for an air-conditioning system, the advantages offered by the claw pole rotor may be realized in optimum fashion, because the claw pole motor makes maximum use of the space that exists anyway in the interior of the fan wheel, and does not require that changes be made to the fan dimensions. Compared to conventional fans for blowers for air conditioning systems, when a fan wheel having the same dimensions is used, a marked reduction in the overall length of the fan is attained, which is now determined only by the axial width or depth of the fan wheel. If the structure of the fan wheel is modified slightly, it can be used simultaneously to cool the claw pole motor, so that the claw pole motor can be designed to be more powerful yet have the same dimensions.  
         [0004]     Advantageous further developments and improvements of the claw pole motor indicated in claim  1  are made possible by the measures listed in claims  2  through  10 .  
         [0005]     A fan with integrated claw pole motor is indicated in claims  11  through  14 .  
         [0006]     A particularly space-saving twin fan for a blower for an air conditioning system may be attained with the features of claim  15 . 
     
    
     DRAWING  
       [0007]     The invention is explained in greater detail in the description hereinbelow with reference to the drawing.  
         [0008]      FIG. 1  is a perspective depiction of a claw pole motor, partially cut away, schematically depicted,  
         [0009]      FIG. 2  is an exploded view of a fan with integrated claw pole motor,  
         [0010]      FIG. 3  is a perspective depiction of a twin fan for a blower for an air conditioning system,  
         [0011]      FIG. 4  is a longitudinal sectional view of the twin fan in  FIG. 3 . 
     
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS  
       [0012]     The claw pole motor—shown in an exploded view in  FIG. 2  and assembled in  FIG. 1 , partially cut away, schematically depicted—has a stator  11  and a rotor  12  situated coaxially thereto, the rotor surrounding stator  11  with an air gap  13  between the two. Stator  11  and rotor  12  form a motor module having a conical shape, whereby the outer diameter of stator  11  and the inner and outer diameter of rotor  12  taper continually in the axial direction. It is understood that the conical shape of stator  11  and rotor  12  must not extend strictly in a straight line, but that they can also deviate therefrom. For example, the conical shape and/or outer shape can be arched outwardly or inwardly. It is also possible that the outer shapes of stator  11  and rotor  12  taper in a stepwise, corresponding manner.  
         [0013]     Stator  11  includes two axially separated yokes  14 ,  15  with integral claw poles  16  and/or  17  and an integral, central sleeve  18  and/or  19  for slipping on and securing yoke  14  and/or  15  to an axis to be described hereinbelow, and a conical ring coil  20  located between yokes  14 ,  15 . As an alternative, ring coil  20  can also be cylindrically wound, if adequate installation space is available given the specified power of the motor and if the motor can be designed less compact in size. Yokes  14 ,  15  with claws  16 ,  17  and sleeves  18 ,  19  are fabricated out of magnetically conductive material. Ring coil  20  is wound on a coil shell  21  that includes a central, hollow-cylindrical core  211  for sliding onto sleeves  18 ,  19  of yokes  14 ,  15 , and two radial flanges  212  and  213  that limit core  211  on the end faces of core  211 , the shape of each of the radial flanges designed to match the shape of adjacent yoke  14 ,  15 . In the claw pole motor having a four-pole configuration as an example, each yoke  14  and/or  15  carries two diametrically situated claws  16  and/or  17 . The two yokes  14 ,  15  are joined such that they are staggered in relation to each other by 90°, so that claws  16 ,  17  extending over ring coil  20  interlock. To manufacture ring coil  20 , coil shell  21  with radial flange  212  is slid into yoke  14  that carries claws  16 , whereby core  211  of coil shell  21  slides onto sleeve  18 . Coil shell  21  is then rotated by 90°, so that radial flange  212  is aligned with yoke  14 . Yoke  15  that carries claws  17  is then slid, with its sleeve  19 , into core  211  of coil shell  21  in such a manner that claws  17  come to rest between claws  16 . The winding wire is then wound onto coil shell  21 , thereby producing conical ring coil  20 .  
         [0014]     In the exemplary embodiment, outer rotor  12  includes a conical magnetic flux return ring  22  that concentrically surrounds stator  11 , and a number of permanent-magnet poles  23 —four permanent-magnet poles  23  in the exemplary embodiment—that corresponds to the number of claws  16 ,  17 , the permanent-magnet poles bearing against inner wall  221  of magnetic flux return ring  23  facing toward claws  16 ,  17 . As shown in  FIG. 2 , permanent-magnet poles  23  are formed by permanent-magnetic shell segments that are joined in the circumferential direction to form a hollow cone. Each of the shell segments is radially magnetized, with adjacent shell segments having opposing directions of magnetization. As an alternative, permanent-magnet poles  23  can also be realized using a closed, conical permanent-magnet ring that is magnetized accordingly. In a modified embodiment, magnetic flux return ring  23  can be eliminated. The permanent-magnet shells are then magnetized in a pole-oriented manner.  
         [0015]     In the single-strand embodiment of claw pole motor depicted in  FIG. 1 , it is advantageous to design claws  16 ,  17  to be asymmetrical, to ensure a defined start-up of the claw pole motor. Ring coil  20  is driven in a bipolar manner. If a unipolar driving of ring coil  20  is desired, then ring coil  20  is composed of two windings that are wound in the opposite direction, the windings being wound on coil shell  21 .  
         [0016]     The single-strand claw pole motor described herein can also be designed with a multiple-strand configuration, e.g., a two or three-strand configuration having any number of strands, by situating a number of motor modules corresponding to the number of strands—the motor modules being composed of stator  11  and rotor  12 , as shown in  FIG. 1 —behind each other in the axial direction. In this case, stators  11  in the adjacent motor modules are staggered in relation to each other; in fact, when two motor modules are involved, they are staggered by 90 electrical degrees, and when m&gt;2 motor modules are involved, they are staggered by 360 electrical degrees/m. Rotors  12  are coupled with each other in torsion-proof fashion. An axial clearance between the individual motor modules ensures magnetic decoupling. As an alternative, instead of stators  11 , rotors  12  carrying permanent-magnet poles  23  can be staggered in relation to each other by the stated angle of rotation.  
         [0017]     The claw pole motor described is used preferably as a drive motor for a fan wheel  25  of a fan configured as a radial fan or an axial-diagonal fan. A fan configured as a radial fan is shown in a perspective view in  FIG. 2 . The claw pole motor is situated in the interior of fan wheel  25 , so that it does not require any additional installation space in the fan. Fan wheel  25  according to  FIG. 2 , which is shown in the right half of  FIG. 4  in a sectional view, has a dish-shaped hub  26  with a conical dish wall  262  and an annular opening edge  261  that surrounds dish opening  263 . Hub  26  is rotationally supported on a fan axis  28  by a bearing  27  ( FIG. 4 ). Fan vanes  29  extend from opening edge  261  of hub  26  parallel to fan axis  28  past dish wall  262 . Fan vanes  29  are stiffened by a circumferential ring  30  on their exposed end furthest from dish opening  263 .  
         [0018]     To install the claw pole motor in the fan wheel  25 , rotor  12  is inserted into hub  26  and secured against the inner surface of conical dish wall  262 . Fan wheel  25  is manufactured as a plastic injection-molded part, whereby the permanent magnet and, if available, magnetic flux return ring  22 , are advantageously formed in hub  26  via injection molding at the same time, using the two-component injection-molding method. This results in a substantial advantage in terms of cost and installation space. Stator  12  is slid with the two central sleeves  18 ,  19  on yokes  14 ,  15  onto fixed fan axis  28  and secured thereto. Fan blades  31  are evenly distributed around the circumference on the opening edge  261  of dish-shaped hub  26 , the fan blades serving to cool the claw pole motor.  
         [0019]     With a two-strand configuration of the claw pole motor, two motor modules that are situated axially behind each other, each of which is composed of a stator  11  and a rotor  12  as described, are inserted into fan wheel  25 . The motor modules are sized in such a manner that they adapt to the conical shape of hub  26 . As a result, the conical motor module in the front—relative to the direction of insertion into hub  26 —has a smaller diameter than the rear conical motor module. The axial length of the motor modules is adjusted accordingly to make the torque produced by the two motor modules the same.  
         [0020]     A fan configured as a twin fan, which is used preferably for blowers for air conditioning systems, is shown in a perspective view in  FIG. 3 . In this case, two identical fans of the type described hereinabove are situated on a common fan axis  28  with axial clearance in such a manner that the opening edges  261  of dish-shaped hubs  26  of fan wheels  25  face toward each other. Corresponding components are labeled with the same reference numerals. A mounting plate  32  is situated between the separated fan wheels  25 , to which the common fan axis  28  is secured. Mounting plate  32  serves to fasten the twin fan in the blower for the air conditioning system and to accommodate electronics for motor control.  
         [0021]     In the depicted exemplary embodiment of the twin fan, one motor module is inserted in each fan wheel  26 , so that each fan wheel  26  is therefore driven by a single-strand claw pole motor. In this case, a two-stranded design of the motor arrangement—with the advantage of defined start-up—may be easily achieved by staggering stators  11  of the two motor modules in relation to each other by 90 electrical degrees, and by coupling the two rotors  12  with each other in torsion-proof fashion. As an alternative, stators  11  can also remain oriented in the same direction relative to each other, of course, and the two fan wheels  26  can be staggered in relation to each other by 90° before they are rigidly connected with each other.