Double-Flexspline Harmonic Reducer for Low-Backlash Wear Tolerance
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Solution Overview
Problem
Harmonic reducers face issues with backlash and manufacturing accuracy, leading to increased costs and reduced lifespan due to wear and tear, which limits the use of cheaper materials and machining processes.
Innovation Solution
A double-flexspline harmonic reducer is introduced, featuring a strong flexspline and a weak flexspline with different tooth counts, allowing for non-circular elastic deformation, which reduces backlash and enhances wear resistance, enabling the use of cheaper materials and machining processes while maintaining precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the manufacturing accuracy of the harmonic reducer is increased to ensure accurate engagement between the flexspline and circular spline, then the backlash is reduced, but the manufacturing cost increases and the selection of cheaper materials and machining processes is limited
Solution Approach 1:
The invention divides the traditional single circular spline into two separate flexsplines (first and second flexsplines) with different tooth counts. This segmentation allows each flexspline to have relaxed manufacturing tolerances while maintaining accurate engagement through their combined interaction, reducing the need for high-precision machining of individual components.
Solution Approach 2:
The invention changes the fundamental parameter of tooth count between the two flexsplines (N1 and N2, where N1 ≠ N2). This parameter difference creates a mechanical constraint system where the engagement accuracy is determined by the relative motion and wear compensation mechanism rather than by the absolute precision of each individual spline, enabling the use of cheaper materials and machining processes.
2Manufacturing precision
If the manufacturing accuracy is increased to prevent backlash, then the engagement is more accurate, but the complexity of machining processes and material selection is restricted
Solution Approach 1:
By segmenting the circular spline function into two flexsplines with different tooth counts, the system distributes the engagement function across multiple components. This segmentation simplifies the machining requirements for each individual component while maintaining overall engagement accuracy through the combined mechanical interaction of the two flexsplines.
Solution Approach 2:
The first and second flexsplines act as intermediary elements between the wave generator and the output shaft. Their different tooth counts create a mechanical mediation system where wear and manufacturing variations are compensated through their relative motion, reducing the need for complex high-precision machining processes.
3Productivity
If the harmonic reducer operates for an extended period, then the production output increases, but the flexspline and circular spline wear causes increased backlash and reduced accuracy life
Solution Approach 1:
The invention changes the tooth count parameter between the two flexsplines to create a wear-compensation mechanism. As the flexsplines wear during extended operation, their relative motion and the difference in tooth counts ensure that engagement accuracy is maintained through the mechanical constraint system, allowing prolonged operation without significant backlash increase.
Solution Approach 2:
The invention introduces dynamic adaptability through the two flexsplines with different tooth counts. The system dynamically compensates for wear during operation through the relative motion and engagement mechanism, allowing the reducer to maintain accuracy over extended operational periods compared to traditional single-spline designs.
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 double-flexspline design improves the tolerance to machining tolerances and wear, prolongs the service life, and reduces manufacturing costs by allowing the use of lower-cost materials and processes while maintaining high precision and minimizing backlash.
Implementation Method 1
the wave generator causes the weak flexspline to undergo non-circular elastic deformation and then to partially engage with the strong flexspline
Implementation Method 2
a contact portion of the strong flexspline and the weak flexspline undergoes non-circular elastic deformation under a radial pressure from the weak flexspline
Data Source
AI summary
Provided is a double-flexspline harmonic reducer, comprising a strong flexspline (3), a weak flexspline (2) and a wave generator (1). The strong flexspline (3) and the weak flexspline (2) are coaxially fixed in an axial direction and a radial direction, and teeth which can be engaged with each other and are different in the number thereof are provided on the strong flexspline (3) and the weak flexspline (2) respectively. The wave generator (1) causes the weak flexspline (2) to undergo non-circular elastic deformation and then to partially engage with the strong flexspline (3), and a contact portion of the strong flexspline (3) and the weak flexspline (2) undergoes non-circular elastic deformation under a radial pressure from the weak flexspline (2). A wall thickness of the strong flexspline (3) is greater than or equal to 2 times and less than 5 times that of the weak flexspline (2).