Totally enclosed motor

1. A totally enclosed motor, comprising:

a rotor disposed inside a housing, and configured to transfer heat of the rotor to the housing, wherein the rotor has a shape different between one end side and the other end side, in an extending direction of a rotary shaft of the rotor;

a stator disposed inside the housing, and configured to transfer heat of the stator to the housing; and

an inner fin disposed in the rotor, and configured to agitate air inside the housing, wherein the inner fin has a height in the axis direction of the rotary shaft that is smaller than a height of a coil at the stator in the axis direction of the rotary shaft;

wherein the totally enclosed motor is cooled by a forced convection by an outer fan disposed outside the housing, or by a natural convention in the vicinity of an outer surface of the housing;

wherein at least two wind holes, other than a gap between the rotor and the stator, passing through between the both end sides in the extending direction of the rotary shaft of the rotor are disposed in at least one of: the rotor, the stator, the rotary shaft, or the housing; and

wherein a wind hole is formed to be inclined from the extending direction of the rotary shaft on an outer surface of the rotor or within the rotor.

2. The totally enclosed motor according to claim 1 ,

wherein the inner fin constitutes at least one fin disposed on one end side, or a plurality of fins disposed on opposite end sides of the rotor in the extending direction of the rotary shaft of the rotor, and each inner fin comprises at least one fin inclined from a radial direction centered around a rotation center of the rotary shaft.

3. The totally enclosed motor according to claim 2 ,

wherein the at least one fin constituting the inner fin is inclined from the radial direction so that pressure distributions of air, which are generated by a rotation of the rotor, in spaces on the respective end sides in the extending direction of the rotary shaft of the rotor are different to each other.

4. The totally enclosed motor according to claim 3 ,

wherein the at least one fin of the inner fin on the one end side and the at least one fin of the inner fin on the other end side in the extending direction of the rotary shaft of the rotor are inclined from the radial direction at the same angle in directions opposite to each other.

5. The totally enclosed motor according to claim 1 ,

wherein the constituent which constitutes the totally enclosed motor is an end ring or a conductor each constituting the rotor, or other constituents of the rotor other than the end ring and the conductor.

6. The totally enclosed motor according to claim 1 ,

wherein the wind hole is formed in, or as, a spiral groove on the outer surface of the rotor.

7. The totally enclosed motor according to claim 6 ,

wherein for a first and a second location disposed on the wind hole, on opposite sides of the rotor in an axial direction, a distance between a rotary shaft disposed orthogonal to the rotor and the first location on the wind hole is greater than a distance between the rotary shaft disposed orthogonal to the rotor and the second location on the wind hole.

8. The totally enclosed motor according to claim 7 ,

wherein the first location on the wind hole is disposed in a no-load side of the totally enclosed motor, and the second location on the wind hole is disposed in a load side of the totally enclosed motor.

9. The totally enclosed motor according to claim 8 , further comprising:

an additional wind hole, other than a gap between the rotor and the stator, disposed in the stator;

wherein the wind hole formed as a spiral groove on the outer surface of the rotor is configured to enable an air flow in the axial direction of the rotor, from the no-load side of the totally enclosed motor to the load side of the totally enclosed motor; and

wherein the additional wind hole is configured to enable a return air flow in the axial direction of the rotor, from the load side of the totally enclosed motor to the no-load side of the totally enclosed motor.