Harmonic Drive Flexible Spline Disc Geometry for Compact Packaging
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Solution Overview
Problem
Conventional harmonic drive apparatuses are limited in achieving even more compact and thinner packaging, which is desirable for applications requiring unique space constraints while maintaining efficient speed reduction.
Innovation Solution
The harmonic drive apparatus incorporates a conical or flat flexible spline disc with a wave generator disc and roller bearings, along with a rigid fixed spline disc, allowing for a compact design by utilizing a saddle-shaped wave surface and rolling engagement with radial gear teeth to achieve reduced size without compromising performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional cylindrical flexible spline is used in a harmonic drive apparatus, then the apparatus achieves standard speed reduction with acceptable backlash, but the packaging envelope cannot be made thinner or more compact
Solution Approach 1:
The patent transitions from a conventional cylindrical flexible spline to a disc-shaped flexible spline with conical or flat configuration. This dimensional change from a cylindrical geometry to a disc geometry with radial gear teeth arranged on a disc surface enables a thinner packaging envelope while maintaining the speed reduction function and acceptable backlash through the radial tooth arrangement engaging with the wave generator disc
Solution Approach 2:
The patent changes the geometric parameters of the flexible spline by introducing a conical or flat disc configuration with radial gear teeth, rather than using the traditional cylindrical configuration. This parameter change allows the apparatus to achieve a reduced packaging envelope volume while maintaining functional performance
2Volume of moving object
If the flexible spline is made thinner to achieve compact packaging, then the packaging envelope volume is reduced, but the structural integrity and gear engagement may be compromised
Solution Approach 1:
The patent employs a flexible spline disc with radial gear teeth that can flex and deform to engage with the wave generator disc. This flexible disc structure maintains structural integrity through its material properties and geometric design, enabling compact packaging while preserving the necessary strength for gear engagement and load transmission
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 thinner packaging solution while maintaining efficient speed reduction, addressing the need for smaller size without increasing backlash or reducing performance.
Implementation Method 1
A plurality of roller bearings are arranged circumferentially around the center axis. The plurality of roller bearings are configured in rolling engagement with the wave generator disc wave surface.
Implementation Method 2
The pair of crests on the wave generator disc push a first and a second group of the flexible gear teeth on the flexible spline disc axially into engagement with a first and a second group of the rigid gear teeth on the fixed spline disc.
Data Source
AI summary
A harmonic drive apparatus (also known as a strain wave gear) is constructed with a circular, flexible spline disc having a generally flat configuration or a slightly conical configuration.