Harmonic drive gears and industrial robots

The harmonic drive gear system addresses adhesive strength and thrust force issues by using a flange-shaped restricting portion on the cam to uniformly restrict the bearing's movement, preventing damage and ensuring stable operation.

JP7841932B2Active Publication Date: 2026-04-07NABTESCO CORP
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Patent Information

Authority / Receiving Office
JP · JP
Patent Type
Patents
Current Assignee / Owner
Filing Date
2022-04-28
Publication Date
2026-04-07

AI Technical Summary

Technical Problem

Conventional harmonic gear devices face issues with adhesive strength between the cam and bearing due to oil intrusion and foreign matter, leading to potential damage from thrust forces, and the use of flanges can hinder lubrication and cause cage deformation.

Method used

A harmonic drive gear system with a bearing that includes a restricting portion formed as a flange-shaped protrusion on the cam's outer surface, ensuring uniform radial protrusion length across the circumference to prevent axial movement and contact with the cage, thereby preventing bearing damage.

Benefits of technology

The system effectively restricts the bearing's axial movement, preventing damage to the cage and ensuring stable operation by maintaining uniform contact and avoiding localized stress on the inner ring.

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Abstract

To provide a wave gear device which can restrict movement of a bearing in a rotation axis direction to prevent damage to the bearing, and to provide an industrial robot.SOLUTION: A wave gear device of an embodiment includes an internal gear 3, an external gear 5, and a wave generator 6. The wave generator 6 has: a cam 31 having a non-circular outer peripheral surface 31a; and a fourth bearing 32 positioned between an inner peripheral surface 21a of the external gear 5 and an outer peripheral surface 31a of the cam 31. The fourth bearing 32 has an outer ring 33, an inner ring 34, a plurality of balls 35, and a retainer 36. The wave gear device includes a restricting portion 37 which comes into contact with the inner ring 34 in such a way as to avoid contact with the retainer 36 and restricts the fourth bearing 32 from moving in a direction of a rotation axis C. The restricting portion 37 is formed such that a radial projection length from the outer peripheral surface 31a of the cam 31 is uniform over the entire periphery of the outer peripheral surface 31a.SELECTED DRAWING: Figure 2
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Citation Information

Patent Citations

  • Harmonic gear transmission wave generator

    JP1991119645U

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    JP2020197264A

  • Wave motion generator for wave motion gear device

    WO2020044524A1

  • Harmonic drive for a robot, and robot comprising a harmonic drive

    WO2022012712A1