Toothless Frictional Wave Reducer for Backlash-Free Robot Joints
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Solution Overview
Problem
Conventional strain wave gearing in industrial robots faces challenges such as high manufacturing costs, precision processing difficulties, decreased rotation accuracy, vibration, noise, and backlash due to tooth formation and friction issues.
Innovation Solution
A frictional wave reducer with a conic pressurizing face and toothless flex and circular splines that utilize surface-to-surface frictional contact instead of teeth, incorporating a pressurizing or pulling mechanism to achieve a reduction gear ratio, allowing for controlled frictional force application without the need for precise tooth formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If teeth are formed in the flex spline and circular spline, then a reduction gear ratio is achieved, but manufacturing costs increase and manufacturing precision becomes difficult
Solution Approach 1:
The patent removes the teeth structure from the flex spline and circular spline, extracting the essential function of tooth engagement and replacing it with friction-based surface contact. This eliminates the need for complex tooth formation processes while maintaining the reduction gear ratio functionality through the interaction between the wave generator's conic pressurizing face and the friction surfaces.
Solution Approach 2:
The patent substitutes the mechanical tooth engagement system with a friction-based contact system. Instead of relying on interlocking teeth, the reduction mechanism achieves its function through frictional contact between the conic pressurizing face of the wave generator and the conic friction surfaces of the flex spline and circular spline, eliminating the need for precise tooth machining.
2Power
If teeth are formed in the splines, then a reduction gear ratio is achieved, but rotation accuracy decreases due to abrasion and processing errors
Solution Approach 1:
By removing the teeth structure entirely, the patent eliminates the sources of abrasion and processing errors associated with tooth formation. The friction-based contact between smooth conic surfaces avoids the wear and precision degradation that occur in toothed mechanisms, thereby maintaining higher rotation accuracy over time.
Solution Approach 2:
The patent changes the contact mechanism from discrete tooth engagement to continuous surface friction contact. This parameter change from point/line contact to surface contact distributes the mechanical interaction more evenly, reducing localized wear and improving the consistency of the reduction ratio, which enhances rotation accuracy.
3Power
If teeth are formed in the splines, then a reduction gear ratio is achieved, but vibration and noise are generated due to friction and processing errors
Solution Approach 1:
The patent replaces the tooth engagement mechanism with a friction-based contact system, substituting the impulsive forces generated by tooth impact with continuous frictional forces. This substitution eliminates the vibration and noise associated with tooth meshing and engagement, as the conic surface friction contact operates more smoothly and quietly.
4Power
If teeth are formed in the splines, then a reduction gear ratio is achieved, but backlash occurs due to rotation clearance
Solution Approach 1:
By removing the teeth structure, the patent eliminates the gaps and clearances that necessarily exist between mating tooth surfaces. The friction-based contact between the conic surfaces maintains continuous engagement without the backlash inherent in toothed mechanisms, as the friction contact adapts to the wave generator's deformation without discrete engagement points.
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 solution reduces manufacturing costs, enhances rotation accuracy, minimizes vibration and noise, and eliminates backlash, while enabling miniaturization and improved durability through surface friction, eliminating the need for expensive lubricants and precise machining.
Implementation Method 1
a frictional wave reducer having an operating principle modified from that of a conventional strain wave gearing... utilize surface-to-surface frictional contact instead of teeth... generating frictional force between the conic friction tube and the internal conic friction face
Data Source
AI summary
The present disclosure relates to a frictional wave reducer mainly used for industrial robot joints and having an operating principle modified from that of a conventional strain wave gearing, which includes a wave generator having a conic pressurizing face on the outermost side, a toothless flex spline having a conic friction tube in which the wave generator is accommodated with the conic pressurizing face inscribed in the conic friction tube, and a toothless circular spline accommodating the toothless flex spline and having an internal conic friction face in which the conic friction tube is inscribed at a plurality of axially symmetrical points to form an internal friction wheel with the toothless flex spline. Accordingly, disadvantages of the conventional strain wave gearing are overcome to provide a reducer having high productivity and high rotation accuracy without generation of vibration and noise.