Gear device and actuator

Patent metadata

Field	Value
Publication number	US-12352336-B2
Application number	US-202418967846-A
Country	US
Kind code	B2
Filing date	Dec 4, 2024
Priority date	Dec 8, 2023
Publication date	Jul 8, 2025
Grant date	Jul 8, 2025

Abstract

A gear device according to the disclosure includes an internal gear having a pin groove, a pin rotatably supported by the pin groove, an external gear oscillatorily rotating while its external tooth is engaging with the pin, and a speed reduction unit. The speed reduction unit decelerates a rotational driving force of an electric motor and transmits the decelerated rotational driving force to a rotating drive unit. The speed reducer includes a first reduction unit disposed on the input side and a second reduction unit disposed coaxially with the first reduction unit on the output side. A gap is formed between the external gear and the pin when the center of the pin groove, the center of the pin, and the tooth bottom of the external gear are aligned. The first gap in the first reduction unit is larger than the second gap in the second reduction unit.

First claim

What is claimed is:

1. A gear device, comprising:
an internal gear having a pin groove on its inner circumference;
a pin rotatably supported by the pin groove;
an external gear oscillatorily rotating while its external tooth is engaging with the pin; and
a speed reduction unit for decelerating a rotational driving force of an electric motor from an input side to an output side and transmitting the decelerated rotational driving force to a rotating drive unit,
wherein the speed reduction unit includes:
a first reduction unit disposed on the input side; and
a second reduction unit disposed coaxially with the first reduction unit on the output side,

wherein a gap is formed between the external gear and the pin when a center of the pin groove, a center of the pin, and a tooth bottom of the external gear are aligned, and
wherein a first gap formed in the first reduction unit is larger than a second gap formed in the second reduction unit.

2. The gear device of claim 1 , wherein a curvature radius of the pin groove is larger than a radius of the pin in the first reduction unit.

3. The gear device of claim 1 , wherein a backlash between the internal gear and the external gear in the first reduction unit is larger than a backlash between the internal gear and the external gear in the second reduction unit.

4. The gear device of claim 1 , wherein a case housing both the first reduction unit and the second reduction unit,
wherein a space in the case is filled with lubricant when a rotation axis of the electric motor is horizontal, and
wherein a filling height of the lubricant is situated above a center shaft of the first reduction unit and at a position where the first reduction unit is not fully filled with the lubricant.

5. The gear device of claim 1 , wherein the gap is formed between the external gear and the pin when the center of the pin groove, the center of the pin, and the tooth bottom of the external gear are aligned, and
wherein the first gap formed in the first reduction unit is larger than the second gap formed in the second reduction unit,
wherein a curvature radius of the pin groove is larger than a radius of the pin in the first reduction unit,
wherein a case housing both the first reduction unit and the second reduction unit is provided,
wherein a space in the case is filled with lubricant when a rotation axis of the electric motor is horizontal, and
wherein a filling height of the lubricant is situated above a center shaft of the first reduction unit and at a position where the first reduction unit is not fully filled with the lubricant.

6. The gear device of claim 3 , wherein a case housing both the first reduction unit and the second reduction unit is provided,
wherein a space in the case is filled with lubricant when a rotation axis of the electric motor is horizontal, and
wherein a filling height of the lubricant is situated above a center shaft of the first reduction unit and at a position where the first reduction unit is not fully filled with the lubricant.

7. A gear device, comprising:
an internal gear; and an external gear oscillatorily rotating while a tooth of the external gear is engaging with a tooth of the internal gear; and a speed reduction unit for decelerating a rotational driving force of an electric motor from an input side to an output side and transmitting the decelerated rotational driving force to a rotating drive unit comprising:
wherein the speed reduction unit includes:
a first reduction unit disposed on the input side; and
a second reduction unit disposed coaxially with the first reduction unit on the output side,
wherein the first reduction unit further includes a carrier holding the external gear,
a case housing both the first reduction unit and the second reduction unit is provided,
wherein the case has a partition wall separating a first space in which the first reduction unit is disposed from a second space in which the second reduction unit is disposed, the partition wall being penetrated via an oil seal by a shaft, which is an output shaft of the first reduction unit,
wherein the first space and the second space are filled with lubricant, and
wherein an inner diameter of the oil seal is smaller than an outer diameter of the carrier.

8. An actuator comprising:
an electric motor; and
the gear device of claim 1 ,
wherein the gear device includes a two-stage speed reduction unit as the reduction unit,
wherein the two-stage speed reduction unit includes the first reduction unit disposed on the input side and the second reduction unit disposed coaxially with the first reduction unit on the output side,
wherein the gap is formed between the external gear and the pin when the center of the pin groove, the center of the pin, and the tooth bottom of the external gear are aligned, and
wherein the first gap formed in the first reduction unit is larger than the second gap formed in the second reduction unit.

9. The actuator of claim 8 , wherein a backlash between the internal gear and the external gear in the first reduction unit is larger than a backlash between the internal gear and the external gear in the second reduction unit.

10. An actuator, comprising:
an electric motor; and
the gear device of claim 7 ,
wherein the gear device includes a two-stage speed reduction unit as the reduction unit,
wherein the two-stage speed reduction unit includes the first reduction unit disposed on the input side and the second reduction unit disposed coaxially with the first reduction unit on the output side,
wherein the first reduction unit further includes the carrier holding the external gear,
wherein the case housing both the first reduction unit and the second reduction unit is provided,
wherein the case has the partition wall separating the first space in which the first reduction unit is disposed from the second space in which the second reduction unit is disposed, the partition wall being penetrated via the oil seal by the shaft, which is the output shaft of the first reduction unit,
wherein the first space and the second space are filled with the lubricant, and
wherein the inner diameter of the oil seal is smaller than the outer diameter of the carrier.

Assignees

• Nabtesco Corp

Inventors

• Yamada Eisuke
• Hatanaka Katsuyuki
• Sakurai Kazuhiko
• Nakamura Koji

Classifications

• F16H2057/02034

  Gearboxes combined or connected with electric machines · CPC title

• F16H57/042

  Guidance of lubricant · CPC title

• F16H57/04

  Features relating to lubrication or cooling {or heating} (control of lubrication or cooling in hydrostatic gearing F16H61/4165) · CPC title

• F16H57/023

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

• F16H57/022

  Adjustment of gear shafts or bearings (for compensating misalignment of axes of toothed gearings without orbital motion F16H1/26; for compensating misalignment of axes of planetary gears F16H1/48) · CPC title