Flat Strain Wave Gearing with Profile-Shifted Flexspline Teeth
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Solution Overview
Problem
Compact flat gearings experience increased stresses on the toothed components near the plane between the circular spline and the dynamic spline, leading to reduced performance and load capacity.
Innovation Solution
The flexspline's toothing in the flank direction is modified with a profile-shifted design, featuring a radially reduced region that axially recedes from the plane between the circular spline and dynamic spline, distributing the load more evenly over the tooth flanks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexspline uses a conventional uniform toothing design, then the manufacturing is simpler, but increased stresses occur on the toothed components near the plane between the circular spline and dynamic spline leading to reduced performance
Solution Approach 1:
The patent applies local quality by modifying the toothing profile specifically in the region affected by high stresses (near the plane between circular spline and dynamic spline). The axial course of the radial position of the tooth is changed only in this critical zone while maintaining uniform toothing in other regions, thus improving reliability where needed without unnecessarily increasing overall device complexity
Solution Approach 2:
The patent changes the geometric parameters of the tooth profile by modifying the axial course of the radial position of the tooth. This parameter change creates a radially reduced region that redistributes stresses and improves the load-bearing capacity of the flexspline, directly addressing the reliability issue while maintaining manufacturability
2Strength
If the radially reduced region is positioned at the plane between circular spline and dynamic spline, then stress peaks are reduced most effectively, but the manufacturing precision requirements increase
Solution Approach 1:
The patent defines specific parameter ranges for the axial course of the radial position of the tooth, with the radially reduced region positioned at the plane between circular spline and dynamic spline. By controlling the parameters within defined ranges (e.g., the axial extent of the radially reduced region), the patent achieves optimal stress reduction while maintaining manufacturability and reasonable precision requirements
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 design reduces stress peaks, enhancing the load capacity and service life of the gearing by at least 25%.
Implementation Method 1
a flexible flexspline arranged within the circular spline and dynamic spline with at least one outer toothing and a wave generator arranged within the flexspline for deforming the flexspline in the radial direction
Implementation Method 2
via a bearing, in particular a thin-section rolling bearing
Data Source
AI summary
A flat gearing in the form of a strain wave gearing includes a circular spline having an inner toothing; a dynamic spline which is axially adjacent to the circular spline and has an inner toothing; a flexible flexspline which is arranged inside the circular spline and dynamic spline and has at least one outer toothing; and a wave generator which is arranged inside the flexspline for deforming the flexspline in the radial direction. An interlocking, torque-transmitting connection is established between the circular spline and the flexspline at two opposing points on the flexspline and between the flexspline and the dynamic spline at four positions on either side of the contact with the circular spline. The axial course of the radial position of the tooth transverse of the at least one outer toothing of the flexspline has a region which is reduced radially in the direction of a center axis of the flat gearing.