Rotor

1. A rotor for a wind or water power machine, the rotor comprising a hub, supported by a main shaft, and a blade, having a root end connected to the hub, wherein,

in a projection plane perpendicular to a rotational center axis of the rotor, a leading edge of the blade has leading edge bulge portions only at two different locations in a rotor radial direction, the leading edge bulge portions each protrudes in a bulge shape forward in a rotor rotational direction, wherein

in the projection plane,

when a tangent line of the hub at a central point in a rotor circumferential direction of the root end of the blade is defined as a first virtual line VL 1 , and

when a virtual line that is parallel to the first virtual line VL 1 and is located on an opposite side of the hub by a distance of 0.50 times a length of the blade BL from the first virtual line VL 1 is defined as a second virtual line VL 2 ,

the leading edge of the blade has a protrusion tip of one of the leading edge bulge portions located inward in the rotor radial direction relative to the second virtual line VL 2 and a protrusion tip of the other leading edge bulge portion located outward in the rotor radial direction relative to the second virtual line VL 2 , and wherein

in the projection plane,

when virtual lines that are parallel to the first virtual line VL 1 and are located on the opposite side of the hub by distances of 0.25 times, 0.75 times and 1.00 times the length of the blade BL from the first virtual line VL 1 are defined as a third virtual line VL 3 , a fourth virtual line VL 4 and a fifth virtual line VL 5 , respectively,

a width BW 1 of the blade along the first virtual line VL 1 , a width BW 2 of the blade along the second virtual line VL 2 , a width BW 3 of the blade along the third virtual line VL 3 , a width BW 4 of the blade along the fourth virtual line VL 4 and a width BW 5 of the blade along the fifth virtual line VL 5 satisfy inequalities of:

BW1<BW3, and

BW3>BW2>BW4>BW5.

2. The rotor according to claim 1 , wherein,

in the projection plane,

a protrusion tip of the leading edge bulge portion located more inward in the rotor radial direction, out of the two leading edge bulge portions, is located forward in the rotor rotational direction with respect to a first line segment L 1 connecting an inward end in the rotor radial direction of the leading edge of the blade and a protrusion tip of the leading edge bulge portion located more outward in the rotor radial direction, out of the two leading edge bulge portions.

3. The rotor according to claim 1 , wherein,

in the projection plane,

a protrusion tip of the leading edge bulge portion located more outward in the rotor radial direction, out of the two leading edge bulge portions, is located forward in the rotor rotational direction with respect to a second line segment L 2 connecting a protrusion tip of the leading edge bulge portion located more inward in the rotor radial direction, out of the two leading edge bulge portions, and an outward end in the rotor radial direction of the leading edge of the blade.

4. The rotor according to claim 1 , wherein,

in the projection plane,

a trailing edge of the blade intersects with a third line segment L 3 at one point, the third line segment L 3 connecting an inward end and an outward end in the rotor radial direction of the trailing edge of the blade,

a portion of the trailing edge of the blade located inward in the rotor radial direction relative to an intersection of the trailing edge of the blade and the third line segment L 3 is located rearward in the rotor rotational direction relative to the third line segment L 3 , and

a portion of the trailing edge of the blade located outward in the rotor radial direction relative to the intersection of the trailing edge of the blade and the third line segment L 3 is located forward in the rotor rotational direction relative to the third line segment L 3 .