Core piece, stator core, stator, and rotary electric machine
View Patent ↗A core piece that is circularly arranged to construct a stator core of an axial gap type rotary electric machine includes: a first member in a column form extending in an axial direction of the stator core; a second member in a plate form disposed on a first end side of the axial direction in the first member; and a third member in a plate form disposed on a second end side of the axial direction in the first member, the first member has a peripheral surface connecting with the second member and the third member, the second member has a protruding portion projecting outwardly from the peripheral surface of the first member, the third member has a protruding portion projecting outwardly from the peripheral surface of the first member, and the first member, the second member, and the third member are configured by an integrally molded green compact.
1. A green compact that is circularly arranged and used in an axial gap type rotary electric machine, the green compact comprising:
an outer peripheral surface located on an outer peripheral side of the green compact;
an inner peripheral surface located on an inner peripheral side of the green compact;
a first lateral surface located on a first direction side of a circumferential direction of the green compact, and connecting with the outer peripheral surface and the inner peripheral surface; and
a second lateral surface located on a second direction side of the circumferential direction of the green compact, and connecting with the outer peripheral surface and the inner peripheral surface, wherein
a length between the first lateral surface and the second lateral surface in the outer peripheral surface is longer than a length between the first lateral surface and the second lateral surface in the inner peripheral surface,
each of the first lateral surface and the second lateral surface has:
a first parallel face connecting with the outer peripheral surface;
a second parallel face connecting with the inner peripheral surface; and
a first inclined face connecting with the first parallel face and the second parallel face,
the first parallel face of the first lateral surface and the first parallel face of the second lateral surface are parallel with each other,
the second parallel face of the first lateral surface and the second parallel face of the second lateral surface are parallel with each other, and
the first parallel face of the first lateral surface and the second parallel face of the first lateral surface are parallel with each other.
2. The green compact according to claim 1 , wherein
an angle formed by an extended plane of the first parallel face and the first inclined face in the first lateral surface is greater than or equal to 5° and less than or equal to 20°, and
an angle formed by an extended plane of the first parallel face and the first inclined face in the second lateral surface is greater than or equal to 5° and less than or equal to 20°.
3. The green compact according to claim 1 , wherein
the outer peripheral surface has a curved surface that is convex toward the outer peripheral side, and
the inner peripheral surface has a curved surface that is convex toward the inner peripheral side.
4. The green compact according to claim 1 , wherein among sites obtained by dividing the green compact into three parts with an imaginary plane along the second parallel face of the first lateral surface, and with an imaginary plane along the second parallel face of the second lateral surface, difference in relative density between a first site on the first direction side of the circumferential direction and a second site on the second direction side of the circumferential direction, and a third site between the first site and the second site is less than or equal to 5.0%.
5. The green compact according to claim 1 , wherein the green compact has a relative density of greater than or equal to 85%.
6. The green compact according to claim 1 , wherein
the green compact is configured by an aggregate of a plurality of coated soft magnetic particles having insulating coating on surfaces of soft magnetic particles, and
the soft magnetic particles are iron-based particles formed of at least one metal selected from the group consisting of pure iron, an Fe—Si-based alloy, an Fe—Al-based alloy, and an Fe—Si—Al-based alloy.
7. A core of an axial gap type rotary electric machine, the core having a plurality of green compacts that are circularly arranged, each of the plurality of green compacts being the green compact according to claim 1 .
8. A stator of an axial gap type rotary electric machine, the stator comprising:
the core according to claim 7 , and
a coil arranged on the core.
9. An axial gap type rotary electric machine comprising a rotor and a stator,
the rotor and the stator being arranged to face with each other in an axial direction,
the stator being the stator according to claim 8 .