Harmonic Drive Roller Carrier for Simpler Flex Spline Assembly
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing strain wave gearing systems, such as harmonic drives, face challenges in assembly complexity due to the need for numerous rollers and separate components, leading to increased time, cost, and potential failure points, while also being bulky and heavy.
Innovation Solution
A drive mechanism for harmonic gear assemblies that integrates an epicyclic carrier unit with pre-mounted rollers and bearings, forming an elliptical shape via a roller carrier, allowing for simplified assembly and reduced contact stress between the wave generator and flex spline.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple rollers and separate bearing components are used to drive the flex spline, then the harmonic drive provides high gear ratio and compact design, but the assembly complexity increases significantly
Solution Approach 1:
The patent combines multiple rollers and bearing components into a single integrated epicyclic carrier unit. The carrier unit includes a carrier with interior circumference matching the shaft, multiple rollers mounted on roller shafts extending parallel to the shaft axis, and bearings facilitating rotation. This integration reduces the number of separate components that need to be assembled while maintaining the high gear ratio functionality through the epicyclic arrangement of rollers at different locations around the carrier circumference.
2Reliability
If numerous rollers are assembled into rows to drive the flex spline, then the drive mechanism achieves proper engagement, but the assembly time and cost increase
Solution Approach 1:
Multiple rollers that would traditionally be assembled separately into rows are now pre-mounted on roller shafts as part of the integrated epicyclic carrier unit. The carrier unit is designed as a single assembly that can be installed as one component, dramatically reducing assembly time and cost while ensuring proper engagement reliability through the predetermined epicyclic arrangement of rollers.
Solution Approach 2:
The rollers and bearings are pre-assembled onto the carrier shafts during manufacturing, creating a pre-assembled epicyclic carrier unit. This preliminary assembly ensures proper positioning and engagement geometry is achieved without requiring time-consuming on-site assembly of individual rollers into rows during system installation.
3Power
If traditional roller and bearing components are used, then the flex spline can be driven, but the overall assembly size and weight increase
Solution Approach 1:
The integration of rollers and bearings into the epicyclic carrier unit eliminates the need for separate bearing races and cages that would add weight. The carrier unit itself serves as the structural element that holds and positions the rollers, creating a more weight-efficient design while maintaining full drive capability for the flex spline through the epicyclic roller mechanism.
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
Simplifies assembly, reduces component count, and minimizes contact stress, resulting in a more compact and reliable drive system suitable for applications requiring high gear ratios and reduced weight.
Implementation Method 1
a first roller rotatably mounted around the first rotor shaft, and a second roller rotatably mounted around the second rotor shaft
Data Source
AI summary
A drive for a harmonic gear assembly, comprising an input shaft having a shaft axis (A) and an epicyclic carrier unit removably mounted around, and coaxial with the input shaft, the epicyclic carrier unit comprising a carrier having an interior circumference designed to match the outer circumference of the shaft and further comprising a first roller assembly mounted at a first location around the circumference of the carrier unit and comprising a first roller shaft extending substantially parallel to the shaft axis and a first roller rotatably mounted around the first rotor shaft, and a second roller assembly mounted at a second location around the circumference of the carrier unit and comprising a second roller shaft extending substantially parallel to the shaft axis and a second roller rotatably mounted around the second rotor shaft, the first and second rollers extending radially outwards from the carrier to define a major axis between the radially outer surfaces of the first and second rollers, and wherein the outer surface of the carrier unit at locations other than the first and second locations defines a minor axis.