×

Permanent magnet type rotating electrical machine and electric power steering device

  • US 8,648,513 B2
  • Filed: 09/26/2008
  • Issued: 02/11/2014
  • Est. Priority Date: 11/15/2007
  • Status: Active Grant
First Claim
Patent Images

1. A permanent magnet type rotating electric machine, comprising:

  • a rotor comprisinga rotor core having a polygonally shaped periphery,a rotating shaft,a plurality of equiangularly arranged reference positions each of which is located in a center of a side of the polygonally shaped periphery at a same radial distance from a center of the rotating shaft, anda plurality of permanent magnets which form magnetic poles, which are arranged on the periphery of the rotor core, and which are shifted in circumferential directions according to a shift pattern which defines shifts of each of the plurality of permanent magnets which specifically target an N-th (N is an integer) order component of a cogging torque and predominantly reduce said N-th order component of the cogging torque; and

    a stator comprising a stator core, slots, and armature windings located in the slots,wherein, when a number of the magnetic poles is M (M is an integer) and a number of the slots is N, M permanent magnets are sequentially numbered from first to M-th in a circumferential direction and are shifted according to the shift pattern, and a positional shift amount from a corresponding one of the equiangularly arranged reference positions for an i-th (i=1, 2, . . . , M) permanent magnet is hi (i=1, 2, . . . , M) (including a sign), M unit vectors in total, each being in an angular direction of 2π

    N(i−

    1)/M (rad), are defined, and a sum of M vectors obtained by multiplying the unit vectors respectively by the positional shift amount hi is smaller than a maximum value of an absolute value of the positional shift amount hi.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×