Strain Wave Gear Layout for Compact Support Strength
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Solution Overview
Problem
Existing strain wave gearings face challenges in maintaining compactness and ensuring sufficient support strength when integrating rotation-transmitting members, often requiring increased axial dimensions or insufficient bearing support.
Innovation Solution
The strain wave gearing incorporates a rigid internally toothed gear, a flexible cup-shaped externally toothed gear capable of radial flexing, a wave generator to induce non-circular shape meshing, and a cover plate to eliminate the need for seals, allowing for a compact and flat design while ensuring support strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a pulley or support mechanism is arranged inside the strain wave gearing, then the device becomes more compact, but sufficient support strength cannot be obtained due to constraints regarding bearing size and arrangement
Solution Approach 1:
The invention changes the arrangement dimension by positioning the rotation-transmitting member and output shaft on the axial-direction side rather than radially inside, allowing sufficient bearing support space while maintaining compact overall structure. The cover plate closes the opposite axial side to maintain compactness in other dimensions.
Solution Approach 2:
The invention segments the support function by providing dedicated bearing arrangements at specific locations (input shaft end supported by boss/cover plate, distal end supported by output shaft), ensuring sufficient support strength independent of the rotation-transmitting member placement.
2Strength
If the axial dimensions are increased to attach the rotation-transmitting member and support mechanism, then sufficient support strength is obtained, but the device dimensions are increased
Solution Approach 1:
Instead of increasing axial dimensions linearly, the invention uses three-dimensional space utilization by arranging components on the axial side with radial clearance, and closes the opposite axial side with a cover plate to maintain compact overall dimensions while providing sufficient support.
Solution Approach 2:
The output shaft is coaxially attached from the axial side to the boss, and the rotation-transmitting member is attached to the protruding input shaft end, creating a nested arrangement where components share space efficiently without increasing overall axial dimension excessively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables a more compact and flatter strain wave gearing while ensuring adequate support strength for the rotation-transmitting member, eliminating the need for additional sealing structures and allowing for efficient rotation transmission.
Implementation Method 1
a flexible externally toothed gear arranged coaxially inside the internally toothed gear, the externally toothed gear being cup-shaped and being capable of flexing in a radial direction
Data Source
AI summary
In a strain wave gearing, both of a pulley for transmitting rotation in a direction orthogonal to a rotation central axis and an output shaft are arranged on an axial-direction first side relative to a cup-shaped externally toothed gear. The input shaft, which transmits input rotation from the pulley to the wave generator, functions as a support shaft for both the pulley and the wave generator and is supported at both ends by the first and second bearings. A mechanism for transmitting rotation from the pulley to the wave generator, and a mechanism for supporting the rotation-transmitting mechanism, can be made compact, and support strength can also be ensured.