WE CLAIM:
1. A rotor (1) for a rotary electric machine, comprising:
a shaft (3);
a rotor core (2) through which the shaft (3) passes, for rotating integrally with the
shaft (3); and
a plurality of permanent magnets (4), each being extended in an axial direction of
the rotor core (2) and being fixed to the rotor core (2) along a circumferential
direction of the rotor core (2),
wherein the rotor core (2) comprises:
a first core portion (20) comprising a plurality of core pieces (5, 6) joined together through caulking portions (2a), and a hollow first lightening portion (20a) separated away from the shaft (3) in a radial direction of the rotor core (2); and
a second core portion (21) comprising a plurality of core pieces (7, 8) joined together through caulking portions (2a), and a press-fit portion (21b) held in close contact with the first core portion (20), into which the shaft (3) is press-fitted,
wherein a radial width of a magnetic path of a ring-shaped outer circumferential portion formed by laminating the first core portion (20) and the second core portion (21) changes along the circumferential direction, and
wherein the shaft (3) passing through a center axis line of the hollow first lightening portion (20a) of the first core portion (20) is surrounded by a ring (10) through a gap portion therebetween.
2. The rotor (1) for a rotary electric machine as claimed in claim 1, wherein the second core portion (21) comprises second core portions (21) arranged on both sides of the shaft (3).
3. The rotor (1) for a rotary electric machine as claimed in claim 1 or 2, wherein the second core portion (21) has hollow second lightening portions (21a) formed around the press-fit portion (21b).
4. The rotor (1) for a rotary electric machine as claimed in claim 3, wherein the hollow second lightening portions (21a) are formed equiangularly so that a number of the hollow second lightening portions (21a) is the same as a number of the plurality of permanent magnets (4).

5. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 4, wherein the radial width of the magnetic path of the ring-shaped outer circumferential portion is larger at a portion between adjacent permanent magnets (4) than a portion immediately below each of the plurality of permanent magnets (4).
6. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 5, wherein the radial width of the magnetic path of the ring-shaped outer circumferential portion changes equiangularly.
7. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 6, wherein the caulking portions (2a) are each formed in a portion immediately below the portion between the adjacent permanent magnets (4).
8. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 7, wherein the caulking portions (2a) of the second core portion (21) are formed in portions connecting the press-fit portion (21b) and the ring-shaped outer circumferential portion, whereas the caulking portions (2a) of the first core portion (20) are formed coaxially with the caulking portions (2a) of the second core portion (21).
9. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 7, wherein the caulking portions (2a) of the first core portion (20) and the caulking portions (2a) of the second core portion (21) are formed in the ring-shaped outer circumferential portion.
10. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 7, wherein the caulking portions (2a) of the second core portion (21) are formed in portions of the press-fit portion (21b), whereas the caulking portions (2a) of the first core portion (20) are formed coaxially with the caulking portions (2a) of the second core portion (21).
11. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 10, wherein the plurality of core pieces (5, 6) of the first core portion (20) and the plurality of core pieces (7, 8) of the second core portion (21) comprise two types of core pieces corresponding to a large core piece and a small core piece having outer circumferential piece portions (5b, 6b) of different width dimensions, the

outer circumferential piece portions (5b, 6b) serving as components of the magnetic path, and
wherein each of the first core portion (20) and the second core portion (21) comprises a laminate of the single large core piece and the single small core piece or a set of a plurality of the large core pieces and a plurality of the small core pieces laminated alternately.
12. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 10, wherein the plurality of core pieces (5, 6) of the first core portion (20) and the plurality of core pieces (7, 8) of the second core portion (21) respectively include outer circumferential piece portions (5b, 6b, 7b, 8b) having the same width dimension, the outer circumferential piece portions (5b, 6b, 7b, 8b) serving as components of the magnetic path.
13. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 12, wherein the rotor core (2) comprises cover pieces (9) for covering both sides of the rotor core (2).
14. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 12, wherein the first core portion (20) comprises first core portions (20), and wherein the second core portion (21) interposed between the first core portions (20) comprises cover pieces (9) for covering both sides of the second core portion (21).
15. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 14, wherein the rotor for a rotary electric machine comprises an IPM-type rotor.
16. The rotor (1) for a rotary electric machine as claimed in any one of claims 1 to 14, wherein the rotor for a rotary electric machine comprises a consequent-pole rotor.
Dated this 17th day of February, 2016
DIGITALLY SIGNED
(RP Bhattacharya)
REG. NO.: IN/PA-60
Of De Penning & De Penning
Agent for the Applicants