Multiple phase claw pole type motor
In a multiple phase claw pole type motor which includes: a plurality of claw poles including a claw portion extending in an axial direction and having a magnetic pole surface facing a rotor in a state of being separated from the rotor by a small gap, a radial yoke portion extending radially outwardly from this claw portion, and an outer peripheral yoke extending from this radial yoke portion in the same direction as the direction of extension of the claw portion; a stator core formed by alternately placing the claw poles in a circumferential direction so that a distal end of each claw portion faces the outer peripheral yoke of an adjacent one of the claw poles; and a stator constructed by sandwiching an annular coil with the adjacent claw poles of this stator core, a multiple phase claw pole type motor characterized in that the claw poles are formed by compacting a magnetic powder and are formed of a magnetic compact having a DC magnetizing property of its flux density becoming 1.7 teslas or more when 10000 A/m of magnetic field is applied.
1. A multiple phase claw pole type motor comprising:
a rotor;
a U-phase stator core, a V-phase stator core and a W-phase stator core, wherein
each of the U, V and W-phase stator cores includes a plurality of claw poles each including:
a claw portion extending in an axial direction and having a magnetic pole surface facing the rotor in a state of being separated from the rotor by a gap,
a radial yoke portion extending radially outwardly from the claw portion, and
an outer peripheral yoke extending from this radial yoke portion in the same direction of extension of the claw portion;
wherein each of the U, V and W-phase stator cores is formed by alternately placing the claw poles in a circumferential direction so that a distal end of each claw portion is adjacent to the radial yoke of a radially adjacent claw pole; and
wherein each of the U, V and W-phase stator cores is constructed by sandwiching an annular coil with the adjacent claw poles of the stator core, wherein:
the claw poles are formed by compacting a magnetic powder to form a magnetic compact having a DC magnetizing property of its flux density becoming 1.7 teslas or more when 10000 A/m of magnetic field is applied, and
the respective claw portions of the U, V and W-phase stator cores are superposed relative to each other so that the magnetic surfaces facing the rotor of the respective claw portions of the U, V and W-phase stator cores are arranged in the axial direction relative to one another,
wherein the annular coil and the plurality of claw poles are unified by being encapsulated together in resin molding after the annular coil is wound.
2. The multiple phase claw pole type motor according to claim 1 , wherein, in each of the U, V and W-phase stator cores, two pairs of the claw poles are formed axially so as to be identical in shape.
3. The multiple phase claw pole type motor according to claim 1 , wherein, each of the U, V and W-phase stator cores, inner corner portions between the claw portion of the claw pole and the radical yoke portion, and between the radical yoke portion and the outer periphery yoke are formed in a concave portion and are constructed of polygonal surfaces.
4. The multiple phase claw pole type motor according to claim 1 , wherein a portion of each claw pole facing an adjacent one of the claw poles is parallel to an axial direction.
5. The multiple phase claw pole type motor according to claim 1 , wherein, in each of the U, V and W-phase stator cores, each of the claw poles has a fitting portion for positioning in an opposite portion to an adjacent one of the claw poles.
6. The multiple phase claw pole type motor according to claim 1 , wherein, in each of the U, V and W-phase stator cores, the claw portion is formed so that its radial thickness increases gradually toward the radial yoke portion from a distal end.
7. The multiple phase claw pole type motor according to claim 1 , wherein the rotor comprises a plurality of permanent magnets facing magnetic pole surfaces of the claw poles, in a circumferential direction; and
wherein the permanent magnets are formed so that gaps between with the magnetic pole surfaces become narrow in their center portions and wide in both sides in a circumferential direction.
8. The multiple phase claw pole type motor according to claim 1 , wherein the claw poles are constructed with being divided every one pole or every two or more poles.
9. The multiple phase claw pole type motor according to claim 1 , wherein the rotor is a rotor which is a salient pole type, a rotor which has a cage type inductor, or a rotor which has both of a cage type inductor and magnets.
10. The multiple phase claw pole type motor according to claim 1 , wherein the motor is adapted to be driven by PWM (Pulse Width Modulation) control.
11. A claw pole type motor according to claim 1 ,
wherein individual magnets formed on said motor are each common to all of the U-phase stator core, the V-phase stator core and the W-phase stator core.
12. A claw pole type motor according to claim 1 , wherein the plurality of claw poles includes recesses, and projections formed on the outer peripheral yoke.