Abstract:
A rotor for brushless motor is disclosed to use locating blocks for securing magnetic plates to peripheral flanges of silicon steel plates being arranged in a stack and sleeved onto a shaft and weight(s) for insertion into peripheral notches of the silicon steel plates to adjust the center of gravity and to keep the rotor in balance.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a motor and more particularly, to a rotor for brushless motor, which produces a great horsepower and reduces the vibration effect. 
         [0003]    2. Description of the Related Art 
         [0004]    A motor is generally comprised of a rotor, and a stator with a winding. When the winding is electrically connected, a magnetic field is produced to bias the rotor. A conventional rotor  10  for brushless motor, as shown in  FIGS. 1˜3 , comprises a shaft  11 , a stack of silicon steel plates  12  sleeved onto the shaft  11 , a plurality of magnetic plates  13  respectively covered on the polar protrusions of the silicon steel plates  12 , and end caps  14  sleeved onto the shaft  11  and secured to two opposite sides of the stack of silicon steel plates  12 . 
         [0005]    This design of rotor still has drawbacks as follows: 
         [0006]    1. The magnetic plates  13  are respectively bonded to the silicon steel plates  12  with an adhesive. After a long use, the adhesive will be aged, resulting in dropping of the magnetic plates  13  from the silicon steel plates  12 . 
         [0007]    2. When the magnetic plates  13  and the silicon steel plates  12  are bonded together, there is no gap in the assembly of magnetic plates  13  and the silicon steel plates  12  for ventilation, resulting in low heat dissipation efficiency of the rotor  10 . 
         [0008]    3. If the center of gravity is not accurately located on the geometrical center after the rotor  10  has been assembled, the position of the center of gravity of the rotor  10  is not adjustable, and the rotor  10  may be unstable during operation. 
       SUMMARY OF THE INVENTION 
       [0009]    The present invention has been accomplished under the circumstances in view. It is therefore one object of the present invention to provide a rotor for brushless motor, which allows adjustment of the position of the center of gravity. It is another object of the present invention to provide a rotor for brushless motor, which facilitates circulation of air for quick dissipation of waste heat. 
         [0010]    To achieve these and other objects of the present invention, the rotor comprises a shaft; a plurality of silicon steel plates arranged in a stack and sleeved onto the shaft, each silicon steel plate comprising a plurality of peripheral notches and peripheral flanges alternatively and equiangularly spaced around the periphery thereof; a plurality of magnetic plates respectively attached to the peripheral flanges of the silicon steel plates and arranged in parallel around the shaft; a plurality of locating blocks respectively inserted into the periphery notches of the silicon steel plates to secure the magnetic plates to the silicon steel plates; counterweight means selectively inserted into the peripheral notches of the silicon steel plates to adjust the center of gravity of the rotor; and two end caps sleeved onto the shaft to secure the silicon steel plates to the shaft. 
     
    
     
       DESCRIPTION OF THE RELATED ART  
         [0011]      FIG. 1  is an exploded view of a rotor for brushless motor according to the prior art. 
           [0012]      FIG. 2  is a cross-sectional view of the rotor for brushless motor according to the prior art. 
           [0013]      FIG. 3  is a sectional side view of the rotor for brushless motor according to the prior art. 
           [0014]      FIG. 4  is an exploded view of a rotor for brushless motor according to the present invention. 
           [0015]      FIG. 5  is an elevational assembly view of the rotor for brushless motor according to the present invention. 
           [0016]      FIG. 6  is a cross-sectional view of the rotor for brushless motor according to the present invention. 
           [0017]      FIG. 7  is a sectional side view of the rotor for brushless motor according to the present invention. 
           [0018]      FIG. 8  corresponding to  FIG. 6 , showing a weight set in the peripheral notches of the silicon steel plates. 
           [0019]      FIG. 9  is an elevational assembly view of an alternate form of the rotor for brushless motor according to the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Referring to  FIGS. 4˜8 , a rotor  20  in accordance with the present invention is shown comprised of a shaft  21 , a stack of silicon steel plates  22  sleeved onto the shaft  21 , a plurality of magnetic plates  25  respectively covered on the silicon steel plates  22 , and end caps  26  sleeved onto the shaft  21  and secured to two opposite sides of the stack of silicon steel plates  22 . Each silicon steel plate  22  has a plurality of peripheral notches  23  and peripheral flanges  24  alternatively and equiangularly arranged around the periphery. The magnetic plates  25  are respectively attached to the peripheral flanges  24  of the silicon steel plates  22  and arranged in a parallel manner around the shaft  21 . 
         [0021]    Further, a plurality of locating blocks  30  are respectively mounted in the peripheral notches  23  of the silicon steel plates  22  and arranged in multiple series around the shaft  21  to secure the magnetic plates  25  to the peripheral flanges  24  of the silicon steel plates  22 . Each locating block  30  has two locating grooves  31  symmetrically disposed at two opposite lateral sides for insertion into one peripheral notch  23  of each of the silicon steel plates  22  and coupling to the corresponding peripheral flanges  24  of the silicon steel plates  22 . 
         [0022]    Further, a weight or weights  40  may be selectively inserted into the peripheral notches  23  of the silicon steel plates  22  (see  FIG. 8 ) to adjust the position of the center of gravity, keeping the rotor  20  in balance. Further, each end cap  26  has a plurality of air holes  27  corresponding to the peripheral notches  23  of the silicon steel plates  22  for guiding currents of air through the peripheral notches  23  of the silicon steel plates  22  for quick dissipation of waste heat. 
         [0023]    Referring to  FIGS. 4 and 6  again, each peripheral notch  23  of each silicon steel plate  22  has an inverted-C configuration defined between two adjacent peripheral flanges  24  of the respective silicon steel plates  22 . Further, the locating blocks  30  have a substantially I-shaped cross section. When inserting the locating blocks  30  into the peripheral notches  23  of the silicon steel plates  22 , the locating grooves  31  of the locating blocks  30  are respectively forced into engagement with the respective peripheral flanges  24  of the respective silicon steel plates  22  and the respective magnetic plates  25 , thereby securing the respective magnetic plates  25  to the respective silicon steel plates  22  firmly. Therefore, it is not necessary to apply an adhesive to the magnetic plates  25  and/or the peripheral flanges  24  of the respective silicon steel plates  22  for bonding the magnetic plates  25  to the respective silicon steel plates  22 . 
         [0024]    Subject to the aforesaid arrangement, the rotor  20  further the advantages as follows: 
         [0025]    1. If the center of gravity of the rotor  20  is biased toward one side, one weight  40  or a number of weights  40  can be inserted into the peripheral notches  23  of the silicon steel plates  22  to adjust the center of gravity of the rotor  20  to the geometrical center of the rotor  20  (as shown in  FIG. 8 ), keeping the rotor  20  in balance and avoiding vibration or noises during operation of the rotor  20 . 
         [0026]    2. As shown in  FIG. 7 , each end cap  26  has a plurality of air holes  27  corresponding to the peripheral notches  23  of the silicon steel plates  22  for guiding currents of air through the peripheral notches  23  of the silicon steel plates  22  for quick dissipation of waste heat. 
         [0027]      FIG. 8  shows an alternate form of the present invention. This alternate form is substantially similar to the embodiment shown in  FIGS. 4˜8  with the exception that this alternate form has two sets of silicon steel plates and magnetic plates arranged on one common shaft, and the magnetic plates of the first set are respectively biased from that of the second set. 
         [0028]    Although particular embodiment of the invention have been described in detail for purposes of illustration, various modifications and enhancements may be made without departing from the spirit and scope of the invention. Accordingly, the invention is not to be limited except as by the appended claims.