Reduction gear and geared motor

Patent metadata

Field	Value
Publication number	US-11578784-B2
Application number	US-202117157012-A
Country	US
Kind code	B2
Filing date	Jan 25, 2021
Priority date	Jan 31, 2020
Publication date	Feb 14, 2023
Grant date	Feb 14, 2023

Abstract

A reduction gear configured to decelerate and output rotation of a motor includes two-stage planetary gear mechanisms that are provided side by side in an axial direction of the motor and are each configured of helical gears, and a case made of resin and formed into a cylindrical shape, the case incorporating the two-stage planetary gear mechanisms. At least one of an inner engagement ratio of a sun gear and a pinion gear of the planetary gear mechanism in a first stage and an outer engagement ratio of the pinion gear and a ring gear of the planetary gear mechanism in the first stage is 3.0 or more, and both the inner engagement ratio and the outer engagement ratio are larger than an engagement ratio of the planetary gear mechanism in a second stage.

First claim

What is claimed is:

1. A reduction gear configured to decelerate and output rotation of a motor, the reduction gear comprising:
two-stage planetary gear mechanisms that are provided side by side in an axial direction of the motor and are each configured of helical gears; and
a case made of resin and formed into a cylindrical shape, the case incorporating the two-stage planetary gear mechanisms,
wherein at least one of an inner engagement ratio of a sun gear and a pinion gear of the planetary gear mechanism in a first stage and an outer engagement ratio of the pinion gear and a ring gear of the planetary gear mechanism in the first stage is 3.0 or more, and both the inner engagement ratio and the outer engagement ratio are larger than an engagement ratio of the planetary gear mechanism in a second stage.

2. The reduction gear according to claim 1 , wherein both the inner engagement ratio and the outer engagement ratio are 3.0 or more.

3. The reduction gear according to claim 2 , wherein a torsion angle of the ring gear of the planetary gear mechanism in the first stage is larger than a torsion angle of a ring gear of the planetary gear mechanism in the second stage.

4. The reduction gear according to claim 2 , wherein the case has a bottomed cylindrical shape having a bottom portion at one axial end and a 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.

5. The reduction gear according to claim 1 , wherein a torsion angle of the ring gear of the planetary gear mechanism in the first stage is larger than a torsion angle of a ring gear of the planetary gear mechanism in the second stage.

6. The reduction gear according to claim 1 , wherein the case has a bottomed cylindrical shape having a bottom portion at one axial end and a 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.

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

8. The reduction gear according to claim 5 , wherein the case has a bottomed cylindrical shape having a bottom portion at one axial end and a 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.

9. A geared motor comprising:
a reduction gear configured to decelerate and output rotation of a motor, the reduction gear comprising:
two-stage planetary gear mechanisms that are provided side by side in an axial direction of the motor and are each configured of helical gears; and
a case made of resin and formed into a cylindrical shape, the case incorporating the two-stage planetary gear mechanisms,
wherein at least one of an inner engagement ratio of a sun gear and a pinion gear of the planetary gear mechanism in a first stage and an outer engagement ratio of the pinion gear and a ring gear of the planetary gear mechanism in the first stage is 3.0 or more, and both the inner engagement ratio and the outer engagement ratio are larger than an engagement ratio of the planetary gear mechanism in a second stage; and
the motor having a shaft integrally rotating with the sun gear of the planetary gear mechanism in the first stage of the reduction gear.

10. The geared motor according to claim 9 , wherein both the inner engagement ratio and the outer engagement ratio are 3.0 or more.

11. The geared motor according to claim 9 , wherein a torsion angle of the ring gear of the planetary gear mechanism in the first stage is larger than a torsion angle of a ring gear of the planetary gear mechanism in the second stage.

12. The geared motor according to claim 9 , wherein the case has a bottomed cylindrical shape having a bottom portion at one axial end and a 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 geared motor according to claim 12 , wherein the lid portion is press-fitted into an opening at the other axial end of the case.

Assignees

• Mabuchi Motor Co

Inventors

• Suwa Masakazu
• Mitsumizo Takao

Classifications

• F16H57/021

  Shaft support structures, e.g. partition walls, bearing eyes, casing walls or covers with bearings · CPC title

• F16H57/028

  characterised by means for reducing vibration or noise · CPC title

• F16H2001/327

  with the orbital gear having internal gear teeth · CPC title

• F16H57/08

  of gearings with members having orbital motion · CPC title

• F16H57/023

  Mounting or installation of gears or shafts in the gearboxes, e.g. methods or means for assembly · CPC title