Patent Publication Number: US-2019190329-A1

Title: Rotor of rotary electric machine

Description:
BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a rotary electric machine, and more particularly to a rotor of the rotary electric machine. 
     Description of the Related Art 
     Recently, the rotary motor adopts the embedded magnet technology to fix the permanent magnet within the rotor to prevent from magnet loosening and demagnetization. However, the magnetic flux leakage is found in the embedded magnet structure such that the researchers focus on improving this problem. 
     With respect to the conventional patents concerning to improve magnetic flux leakage, the EP2201663 discloses two irregular pentagonal spaces arranged on one end of each magnet slot, the JP3425176 discloses two triangular spaces arranged on one end of each magnet slot, and the JP5954279 discloses a rotor with multiple planar edges corresponding to the magnet slots respectively. 
     Although the above mentioned technologies can improve magnetic flux leakage, the limited effect still needed to be developed. 
     SUMMARY OF THE INVENTION 
     In view of the disadvantages of prior art, the object of the present invention is to provide a rotor of the rotary electric machine to decrease the iron loss and the torque. 
     To achieve the above object, the present invention provides a rotor of the rotary electric machine comprising a ring, a plurality of magnetic pole portions, a plurality of slots and a plurality of magnets. Each magnetic pole portion comprises two magnetic portions with an angle (C) between 20°  ˜ 90°. The slots are configured between the magnetic pole portions to hold the magnets. 
     In one embodiment of the present invention, the ring comprises a plurality of supports radially configured on the ring. 
     In one embodiment of the present invention, each of the magnetic pole portions comprises two protrusions opposite with each other and extended toward the slots. 
     In one embodiment of the present invention, each of the magnets comprises a first width (W1), and each of the magnetic pole portions comprises a second width (W2); the first width (W1) and the second width (W2) fulfill with the following equation: 
     
       
         
           
             
               
                 W 
                  
                 
                     
                 
                  
                 1 
               
               4 
             
             ≤ 
             
               W 
                
               
                   
               
                
               2 
             
             ≤ 
             
               
                 W 
                  
                 
                     
                 
                  
                 1 
               
               2 
             
           
         
       
     
     In one embodiment of the present invention, each of the magnets comprises a first width (W1) and each of the magnetic pole portions comprises a third width (W3) wherein the third width (W3) is larger than the first width (W1). 
     In one embodiment of the present invention, each of the magnets comprises a first length (L1), and each of the magnetic pole portions comprises a connection portion with a second length (L2) wherein the first length (L1), the second length (L2) and the angle (C) fulfill with the following equation: 
       0.5 L 1×cos( C )≤ L 2
 
     In one embodiment of the present invention, the angle (C) is 25°, 50° or 80°. 
     Accordingly, the rotor of the rotary electric machine provides the angle (C) defined between 20°  ˜ 90° to concentrate the magnetic field of the rotor and decrease the iron loss of the rotor. The relation between the first width W1 of the magnet  40  and the second width W2 of the connection portion  25  is modified to decrease the torque. The relation between the first length L1 of the magnet  40  and the second length L2 of the connection portion  25  is predetermined to raise the flux linkage and decrease the iron loss of the rotor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view of the rotor of the rotary electric machine according to the first embodiment of the present invention; 
         FIG. 2  is an exploded view of the rotor of the rotary electric machine according to the first embodiment of the present invention; 
         FIG. 3  is a cross sectional view of the rotor of the rotary electric machine along the line  3 - 3  of  FIG. 1 ; 
         FIG. 4  is a partial plan view of the rotor of the rotary electric machine according to the first embodiment of the present invention; 
         FIG. 5  is a partial plan view of the rotor of the rotary electric machine according to the second embodiment of the present invention; 
         FIG. 6  is a partial plan view of the rotor of the rotary electric machine according to the third embodiment of the present invention; 
         FIG. 7  is a chart illustrating the relation between the angle and the torque of the present invention; and 
         FIG. 8  is a chart illustrating the relation between the second width W2 and the torque. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Refer to  FIG. 1  to  FIG. 4  which illustrate the rotor of the rotary electric machine according to the first embodiment of the present invention. The rotor of the rotary electric machine includes a ring  10 , a plurality of magnetic pole portions  20 , a plurality of slots  30 , a plurality of magnets  40 , a fixture  50 , a disc  60  and a plurality of connecting units  70 . 
     The magnetic pole portions  20  are positioned on the ring  10  radially wherein the slots  30  are configured between the magnetic pole portions  20 . The ring  10  includes a plurality of supports  11  radially extruded on the ring  10  wherein the supports  11  are configured between the magnetic pole portions  20  and corresponds to the slots  30 . Besides, each magnetic pole portion  20  includes two protrusions  21  opposite with each other and extended toward the slots  30  to provide two protrusions within each slot  30 . The magnets  40  are held within the slots  30  through the supports  11  extruded on the ring  10  and the protrusions  21  extended toward the slots  30 . 
     The fixture  50  is located at one end of the rotor and partially within the rotor. The disc  60  is set against the other end of the rotor. The fixture  50  includes a plurality of first linking holes  51 , and the disc  60  includes a plurality of second linking holes  61  wherein the first linking holes  51  and the second linking holes  61  correspond to the through holes  12  of the ring  10 . The connecting units  70  are secured within the first linking holes  51 , the through holes  12  and the second linking holes  61  to fasten the rotor between the fixture  50  and the disc  60  for assembly. In this embodiment, the connecting units  70  are bolts. In other embodiment, the connecting units  70  are screws and the first linking holes  51 , the through holes  12  and the second linking holes  61  are screw holes to provide another design selection. 
     Specifically, each magnetic pole portion  20  comprises two magnetic portions  22  adjacent to the ring  10 . Each magnetic portion  22  comprises a lateral side  23  and an inclined side  24  wherein an angle C is provided between the lateral side  23  and the inclined side  24 . In this embodiment, the angle C is 25°. With the angle C of the magnetic portion  22 , the magnetic field of the rotor is concentrated and the flux linkage is raised to decrease the iron loss of the rotor. 
     Moreover, each magnet  40  includes a first width W1 defined by two corresponding lateral sides  23  of contiguous magnetic pole portions  20 . Each magnetic pole portion  20  includes a connection portion  25  connected with the ring  10  wherein each connection portion  25  includes two edges defining a second width W2. The first width W1 and the second width W2 fulfill with the following equation: 
     
       
         
           
             
               
                 W 
                  
                 
                     
                 
                  
                 1 
               
               4 
             
             ≤ 
             
               W 
                
               
                   
               
                
               2 
             
             ≤ 
             
               
                 W 
                  
                 
                     
                 
                  
                 1 
               
               2 
             
           
         
       
     
     Each magnetic pole portion  20  includes a third width W3 defined by two lateral sides  23  of each magnetic pole portion  20  wherein the third width W3 of each magnetic pole portion  20  is larger than the first width W1 of each magnet  40 . 
     Each magnet  40  includes a first length L1, and each connection portion  25  of each magnetic pole portion  20  includes a second length L2 wherein the first length L1, the second length L2 and the angle C fulfill with the following equation: 
       0.5 L 1×cos( C )≤ L 2
 
     In this embodiment, the angle C is 25°. In other embodiment, the angle C can be defined between 20° ˜ 90°, such as the angle C of 50° shown in  FIG. 5  and the angle C of 80° shown in  FIG. 6 . 
     Refer to  FIG. 7  showing the chart which illustrates the relation between the angle C of the magnetic portion  22  and the torque wherein the X axis shows the degree of the angle C and the Y axis shows the value of the torque. The chart reveals that the torque decreases as the rise of the angle C. 
     Refer to  FIG. 8  showing the chart which illustrates the relation between the second width W2 of the connection portion  25  and the torque wherein the X axis shows the distance of the second W2 and the Y axis shows the value of the torque. The chart reveals that the torque decreases as the rise of the second W2. 
     Therefore, the rotor of the rotary electric machine of the present invention provides the magnetic pole portions  20  with magnetic portions  22  wherein each magnetic portion  22  comprises an angle C defined by the lateral side  23  and the inclined side  24  and between 20°  ˜ 90° to concentrate the magnetic field of the rotor and decrease the iron loss of the rotor. In addition, each magnetic pole portion  20  includes a connection portion  25  with the second width W2 thereby modifying the relation between the first width W1 of the magnet  40  and the second width W2 of the connection portion  25  to decrease the torque. Furthermore, the relation between the first length L1 of the magnet  40  and the second length L2 of the connection portion  25  is predetermined to raise the flux linkage and decrease the iron loss of the rotor.