Circular Wave Drive Reduces Vibration and Wear
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Solution Overview
Problem
Current power transmission and speed reduction devices, such as harmonic and cycloidal drives, face issues like material fatigue, complex construction, high vibration, and wear due to their design, which limits their performance and lifespan.
Innovation Solution
The circular wave drive, featuring a ring-shaped wheel with internal and external friction elements and a wave generator with an eccentric input shaft, provides a simpler, compact design with adjustable speed reduction ratios and minimal backlash, utilizing friction between components to achieve efficient power transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a harmonic drive is used for power transmission and speed reduction, then power transmission capability is improved, but the flexspine material fatigue limits the speed reduction ratio and torque transfer
Solution Approach 1:
The patent removes the flexspine component from the harmonic drive system and replaces it with a rigid ring gear that has teeth engaging with a wave generator. This extraction eliminates the material fatigue problem inherent in flexspines while maintaining the core function of speed reduction and power transmission through the tooth engagement mechanism.
Solution Approach 2:
The patent substitutes the flexible deformation mechanism of the harmonic drive with a rigid tooth engagement mechanism. Instead of relying on elastic deformation of the flexspine, the system uses mechanical tooth-to-tooth engagement between the wave generator and ring gear, replacing the mechanical principle from elastic deformation to rigid body mechanics.
2Force
If a cycloidal drive is used for speed reduction, then torque transfer is improved, but the construction becomes complex with many moving parts
Solution Approach 1:
The patent combines the input and output shafts into a single common axis, eliminating the need for separate input and output shafts that are characteristic of cycloidal drives. This merging of shafts simplifies the overall construction while maintaining the torque transfer capability through the wave generator and ring gear engagement.
Solution Approach 2:
The wave generator serves multiple functions: it provides the input rotation, engages with the ring gear teeth to achieve speed reduction, and the output is taken from the same axis. This multi-functionality reduces the number of separate components needed compared to traditional cycloidal drives that require distinct input and output shafts.
3Force
If a cycloidal drive is used for speed reduction, then torque transfer is improved, but vibration is produced through eccentric rotation
Solution Approach 1:
The patent introduces asymmetry through the wave generator, which has an asymmetric cross-section that engages with the ring gear teeth in a controlled manner. This asymmetric engagement allows for smooth torque transfer while the symmetric arrangement of teeth around the circle balances out vibrations, unlike the single-point eccentric contact in traditional cycloidal drives.
4Force
If a cycloidal drive is used for speed reduction, then torque transfer is improved, but wear occurs at contact points between rollers and receiving holes
Solution Approach 1:
The patent replaces the roller-to-hole contact mechanism of cycloidal drives with a tooth-to-tooth engagement system. The wave generator teeth engage with the ring gear teeth through rolling and sliding contact that is distributed across multiple tooth pairs, eliminating the concentrated wear points at roller-receiving hole interfaces and significantly extending component life.
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
The circular wave drive offers a wide range of speed reduction ratios from 30:1 to 10,000:1 with reduced vibration and wear, providing a more reliable and long-lasting solution compared to existing technologies.
Implementation Method 1
a ring-shaped wheel residing in the chamber, wherein the ring-shaped wheel includes both an external friction element and an internal friction element... wherein the circular wall includes a friction element... a peripheral face of the wheel-driven portion includes a friction element being in contact with the internal friction element of the ring-shaped wheel
Data Source
AI summary
A circular wave drive system, and a method for use of a circular wave drive, are provided. In one embodiment, a circular wave drive is provided, the circular wave drive comprising: a substantially enclosed housing having a chamber therein, a ring-shaped wheel residing in the chamber, a wave generator having a wheel-driving portion that is oriented within the hollow central portion of the ring-shaped wheel; and an output element having a wheel-driven portion that is oriented within the hollow central portion of the ring-shaped wheel opposite the wheel-driving portion of the wave generator.