Wave Motion Speed Reducer Radial Support Stiffness
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Solution Overview
Problem
Existing speed reduction and increase apparatuses face limitations in rotational stiffness due to small diameter spline joints and suffer from poor gear efficiency due to triangular or trapezoidal tooth shapes leading to slipping rather than rolling.
Innovation Solution
A speed reduction or increase apparatus with a support unit placed radially outward to allow wave motion of the first crown gear and featuring convex and concave cone-shaped top and bottom portions on the gears for smooth engagement, enhancing rotational stiffness and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the spherical spline joint is placed radially inward of the first crown gear, then the device complexity is reduced, but the rotational stiffness of the speed reduction apparatus cannot be increased
Solution Approach 1:
The support unit is inverted from the conventional radial inward placement to a radial outward placement relative to the first crown gear. This inversion allows the spline joint to be positioned at a larger diameter, increasing the rotational stiffness of the speed reduction apparatus while maintaining structural feasibility through the spherical support configuration
2Ease of manufacture
If the teeth of the first and second crown gears are formed into a triangular or trapezoidal shape, then the ease of manufacture is improved, but the gear efficiency deteriorates due to slipping rather than rolling
Solution Approach 1:
The gear teeth are transformed from angular triangular or trapezoidal shapes to curved spherical segment shapes. This curvature enables rolling contact between engaging teeth, eliminating slipping and improving gear efficiency, while the spherical geometry remains compatible with standard manufacturing processes for crown gears
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 apparatus achieves increased rotational stiffness and improved gear efficiency through enhanced support and smooth rolling contact between gears, addressing the limitations of existing technologies.
Implementation Method 1
the first crown gear is caused to undergo wave motion in such a manner that the location of contact moves
Implementation Method 2
The first crown gear is supported by a spherical spline joint placed radially inward of the first crown gear in such a manner as to be capable of wave motion
Implementation Method 3
the first crown gear and the second crown gear alternately include a top portion and a bottom portion in a circumferential direction, the top portion is of a convex shape based on a side surface of a cone, and the bottom portion is of a concave shape based on a side surface of a cone
Data Source
AI summary
Provided is a speed reduction or speed increasing apparatus where the rotational stiffness can be increased, including a housing, a first crown gear, a support unit placed radially outward of the first crown gear to support the first crown gear to be capable of wave motion and incapable of rotation with respect to the housing, a second crown gear configured to be rotatable with respect to the housing, the second crown gear having a different number of teeth from the first crown gear, the second crown gear facing the first crown gear, and a cam unit configured to incline the first crown gear with respect to the second crown gear in such a manner that the first crown gear engages with the second crown gear, and to cause the first crown gear to undergo wave motion in such a manner that the location of contact moves.