Reduction gear and geared motor

1. A reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction, the reduction gear comprising:

a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and

a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case and extends along at least a part of an inner peripheral surface in an axial central portion of the case.

2. The reduction gear according to claim 1 , wherein the reinforcing component has a ring shape extending over an entire circumference of the case in the axial central portion of the case.

3. The reduction gear according to claim 2 , wherein the reinforcing component is located between pinion gears of the two-stage planetary gear mechanisms.

4. The reduction gear according to claim 2 ,

wherein the inner peripheral surface of the case includes a small-diameter inner peripheral surface and a large-diameter inner peripheral surface having different inner diameters from each other in the axial direction, and a tapered surface connecting the small-diameter inner peripheral surface and the large-diameter inner peripheral surface and inclined in the axial direction, and

the reinforcing component is press-fitted into the case and disposed at a position in contact with a boundary line between the large-diameter inner peripheral surface and the tapered surface.

5. The reduction gear according to claim 2 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side.

6. The reduction gear according to claim 5 , wherein the lid portion is press-fitted into an opening at the other axial end of the case.

7. The reduction gear according to claim 1 , wherein the reinforcing component is located between pinion gears of the two-stage planetary gear mechanisms.

8. The reduction gear according to claim 7 ,

wherein the inner peripheral surface of the case includes a small-diameter inner peripheral surface and a large-diameter inner peripheral surface having different inner diameters from each other in the axial direction, and a tapered surface connecting the small-diameter inner peripheral surface and the large-diameter inner peripheral surface and inclined in the axial direction, and

the reinforcing component is press-fitted into the case and disposed at a position in contact with a boundary line between the large-diameter inner peripheral surface and the tapered surface.

9. The reduction gear according to claim 7 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side.

10. The reduction gear according to claim 9 , wherein the lid portion is press-fitted into an opening at the other axial end of the case.

11. The reduction gear according to claim 1 ,

wherein the inner peripheral surface of the case includes a small-diameter inner peripheral surface and a large-diameter inner peripheral surface having different inner diameters from each other in the axial direction, and a tapered surface connecting the small-diameter inner peripheral surface and the large-diameter inner peripheral surface and inclined in the axial direction, and

the reinforcing component is press-fitted into the case and disposed at a position in contact with a boundary line between the large-diameter inner peripheral surface and the tapered surface.

12. The reduction gear according to claim 11 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side.

13. The reduction gear according to claim 12 , wherein the lid portion is press-fitted into an opening at the other axial end of the case.

14. The reduction gear according to claim 1 , wherein the case has a bottomed cylindrical shape having the bottom portion at one axial end and the lid portion at another axial end, and is attached to the motor in a direction in which the bottom portion is located on a motor side.

15. The reduction gear according to claim 14 , wherein the lid portion is press-fitted into an opening at the other axial end of the case.

16. A geared motor comprising:

a reduction gear configured to decelerate and output rotation of a motor by two-stage planetary gear mechanisms disposed side by side in an axial direction, the reduction gear comprising:

a case made of resin, the case being formed into a cylindrical shape in which the two-stage planetary gear mechanisms are incorporated, and having at least one of a lid portion and a bottom portion provided at each of both axial ends; and

a reinforcing component that is formed of a material having a Young's modulus higher than a Young's modulus of a material of the case and extends along at least a part of an inner peripheral surface in an axial central portion of the case; and

the motor having a shaft integrally rotating with a sun gear of the planetary gear mechanism in a first stage of the reduction gear.