General purpose engine with axial gap type motor/generator

1. A general purpose engine, comprising:

an engine main body;

a rotary shaft which is rotated by a driving force of said engine main body; and

an axial gap type motor/generator attached integrally to said rotary shaft,

wherein said axial gap type motor/generator comprises:

a power generating rotor that rotates integrally with said rotary shaft;

a stator that is attached to said engine main body, a distance between said power generating rotor and the engine main body being greater than a distance between said stator and the engine main body, wherein a central portion of said stator comprises a hollow site for air to flow from said power generating rotor toward said stator; and

a fin member inserted into the hollow site of said stator.

2. The general purpose engine according to claim 1 , wherein a plurality of magnets are attached, in circumferential direction series, to an opposing face of said power generating rotor opposing said stator, and

wherein a plurality of coils are attached and connected to said stator.

3. The general purpose engine according to claim 1 , further comprising a back yoke disposed on said rotary shaft on a side closer to said engine main body than said stator and at a predetermined distance from said stator.

4. The general purpose engine according to claim 3 , further comprising an attachment member that extends in a substantially linear form,

wherein an outer diameter of said stator is larger than an outer diameter of said back yoke, and

wherein one end of said attachment member is attached to said engine main body and another end of said attachment member is attached to a site of said stator having a larger diameter than said back yoke.

5. The general purpose engine according to claim 1 , further comprising a plurality of first fins provided on said power generating rotor and arranged in said circumferential direction.

6. The general purpose engine according to claim 5 , further comprising an air vent provided in said power generating rotor on an inside of said first fins so as to penetrate said power generating rotor in an axial direction of said rotary shaft.

7. The general purpose engine according to claim 6 , wherein the fin member rotates integrally with said rotary shaft, and a plurality of second fins are arranged on the fin member in said circumferential direction.

8. The general purpose engine according to claim 7 , wherein said fin member is formed integrally with said power generating rotor or a back yoke disposed on said rotary shaft.

9. The general purpose engine according to claim 1 , wherein said power generating rotor functions as a flywheel for stabilizing a rotary force of said rotary shaft, using self-generated inertial force.

10. The general purpose engine according to claim 1 , wherein an ignition magnet for detecting a rotation angle of said rotary shaft is attached to said power generating rotor.

11. The general purpose engine according to claim 1 , further comprising a recoil starter that is disposed on a side farther away from said engine main body than said power generating rotor and forcibly rotates said rotary shaft upon start-up of said engine main body.

12. A general purpose engine, comprising:

an engine main body;

a rotary shaft which is rotated by a driving force of said engine main body; and

an axial gap type motor/generator attached integrally to said rotary shaft,

wherein said axial gap type motor/generator comprises:

a first flywheel that rotates integrally with said rotary shaft and stabilizes a rotary force of said rotary shaft, using self-generated inertial force;

a stator which is attached to said engine main body, a distance between the first fly wheel and the engine main body being greater than a distance between the stator and the engine main body, and to which a plurality of coils are connected and attached, wherein a plurality of magnets is attached, in circumferential direction series, to an opposing face of said first flywheel opposing said stator, and wherein a central portion of said stator comprises a hollow site for air to flow from said first flywheel toward said stator; and

a fin member inserted into the hollow site of said stator.

13. The general purpose engine according to claim 12 , further comprising a second flywheel, which is disposed on said rotary shaft on a side closer to said engine main body than said stator and at a remove from said stator, and which functions as a back yoke.

14. The general purpose engine according to claim 13 , further comprising an attachment member that extends in a substantially linear form, wherein an outer diameter of said stator is larger than an outer diameter of said second flywheel, and

wherein one end of said attachment member is attached to said engine main body and another end of said attachment member is attached to a site of said stator having a larger diameter than said second flywheel.

15. The general purpose engine according to claim 12 , further comprising a plurality of first fins provided on said first flywheel and arranged in said circumferential direction.

16. The general purpose engine according to claim 15 , further comprising an air vent provided in said first flywheel on an inside of said first fins so as to penetrate said flywheel in an axial direction of said rotary shaft.

17. The general purpose engine according to claim 16 , wherein the fin member rotates integrally with said rotary shaft, and a plurality of second fins are arranged on the fin member in said circumferential direction.

18. The general purpose engine according to claim 17 , wherein said fin member is formed integrally with said first flywheel or said second flywheel.

19. The general purpose engine according to claim 12 , wherein an ignition magnet for detecting a rotation angle of said rotary shaft is attached to said first flywheel.

20. The general purpose engine according to claim 12 , further comprising a recoil starter that is disposed on an outside of said first flywheel and forcibly rotates said rotary shaft upon start-up of said engine main body.