Strain wave gearing

Patent metadata

Field	Value
Publication number	US-2024410457-A1
Application number	US-202118699493-A
Country	US
Kind code	A1
Filing date	Nov 5, 2021
Priority date	Nov 5, 2021
Publication date	Dec 12, 2024
Grant date	—

Abstract

A strain wave gearing includes a wave generator that creates a state in which a flexible externally toothed gear is flexed into a non-circular shape and partially meshes with a rigid internally toothed gear, and that includes a wave plug having a non-circular outer peripheral surface and a wave bearing attached to the non-circular outer peripheral surface of the wave plug. The wave bearing includes an outer ring having an inner peripheral surface and an outer-ring-side raceway surface formed on the inner peripheral surface, an inner ring having an outer peripheral surface and an inner-ring-side raceway surface formed on the outer peripheral surface, and a plurality of rolling elements rotatably inserted between the outer-ring-side raceway surface and the inner-ring-side raceway surface,

First claim

1 - 10 . (canceled)

11 . A strain wave gearing comprising:
a wave generator that creates a state in which a flexible externally toothed gear is flexed into a non-circular shape and partially meshes with a rigid internally toothed gear, the wave generator including
a wave plug having a non-circular outer peripheral surface, and
a wave bearing attached to the non-circular outer peripheral surface of the wave plug, and including
an outer ring having an inner peripheral surface and an outer-ring-side raceway surface formed on the inner peripheral surface,
an inner ring having an outer peripheral surface and an inner-ring-side raceway surface formed on the outer peripheral surface, and
a plurality of rolling elements rotatably inserted between the outer-ring-side raceway surface and the inner-ring-side raceway surface,

wherein each of the outer ring and the inner ring is a component made of a super engineering plastic, wherein the plurality of rolling elements is cylindrical rollers arranged at equal angular intervals in a circumferential direction of the wave bearing, the number of cylindrical rollers is an odd number of 13 or greater, and a relationship,
D≤PCD× 0.2
is satisfied, where D is a roller diameter of each of the cylindrical rollers and PCD is a raceway groove diameter of the wave bearing prior to being flexed into the non-circular shape, wherein the internally toothed gear and the externally toothed gear are gears having modulus m, a difference in the number of teeth between the internally toothed gear and the externally toothed gear is 2n, n being a positive integer, the externally toothed gear is flexed into an ellipsoidal shape by the wave generator, and a relationship,
df≥ 2 n×m
is satisfied, where df is an amount of flexure of the externally toothed gear as an ellipticity of the ellipsoidal shape, wherein a pressure angle of each of teeth of the internally toothed gear and the externally toothed gear is a low pressure angle equal to or less than 20 degrees, and wherein the inner-ring-side raceway surface and the outer-ring-side raceway surface are formed thereon with a transfer film made of fine powder of an ionic crystalline layered compound and are coated with grease.

12 . The strain wave gearing of claim 1 , wherein
the outer ring is integrally formed on the externally toothed gear, and the externally toothed gear is a component made of the super engineering plastic.

13 . The strain wave gearing of claim 1 , wherein
the inner ring is integrally formed on the wave plug, and the wave plug is a component made of the super engineering plastic.

Assignees

• Harmonic Drive Systems

Inventors

• Kobayashi Masaru

Classifications

• F16H2049/006

  Wave generators producing a non-elliptical shape of flexsplines, i.e. with a qualified different shape than elliptical · CPC title

• F16H2049/003

  Features of the flexsplines therefor · CPC title

• F16H1/32 Primary

  in which the central axis of the gearing lies inside the periphery of an orbital gear · CPC title

• F16H49/001 Primary

  Wave gearings, e.g. harmonic drive transmissions · CPC title