Spiral Drive and Helical Driven Gear Layout for Compact Reduction
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Solution Overview
Problem
Conventional gear reduction mechanisms with noncoplanar rotation axes, such as those involving worms, face challenges in increasing the diameter of the drive gear without significantly increasing manufacturing costs and accommodating limited radial space, which hinders compatibility with application targets.
Innovation Solution
A gear reduction mechanism featuring a drive gear with spiral teeth having a constant radial pitch and a helical driven gear with a helix angle within a specified range, allowing for increased diameter without the need for rotation removal and improved spatial adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the diameter of the drive gear is increased to reduce rotational speed more effectively, then the gear reduction ratio is improved, but the manufacturing cost increases due to rotation removal requirements for worm molding
Solution Approach 1:
The patent inverts the conventional worm gear configuration by making the drive gear a spiral face gear instead of a worm, and the driven gear a helical gear instead of a worm wheel. This inversion eliminates the need for rotation removal in resin molding while achieving the same gear reduction function, thereby reducing manufacturing costs.
Solution Approach 2:
The patent changes the fundamental geometric parameters of the gear system by adopting spiral teeth with constant radial pitch on the drive gear and corresponding helical teeth on the driven gear. This parameter change enables larger drive gear diameters without the manufacturing cost penalty associated with conventional worm gears.
2Power
If the diameter of the drive gear is increased to improve gear reduction performance, then the rotational speed reduction is enhanced, but the radial space requirement increases making it difficult to adapt to application targets with limited space
Solution Approach 1:
The patent transitions from the conventional radial arrangement of worm gears to a configuration where the driven gear is arranged in the axial direction of the drive gear. This dimensional change allows the drive gear to have a larger diameter for better gear reduction performance without proportionally increasing the radial space footprint, as the space utilization extends into the axial dimension.
3Power
If the drive gear diameter is increased while maintaining conventional worm geometry, then the gear reduction capability is improved, but the compatibility with application targets is reduced due to space constraints
Solution Approach 1:
By inverting the conventional worm gear configuration to use spiral face gears and helical gears, the patent achieves better gear reduction capability with improved adaptability. The new configuration allows flexible arrangement in limited spaces while maintaining effective gear reduction, thereby enhancing compatibility with various application targets.
Data Source
AI summary
A gear reduction mechanism (1) includes a drive gear (10) having a rotation axis (L1), and a driven gear (20) driven in mesh with the drive gear (10) and having a rotation axis (L2) that is noncoplanar with the rotation axis (L1). The drive gear (10) is provided with spiral teeth, each having a tooth trace of a spiral curve having a spiral center on the rotation axis (L1) and a constant radial pitch, when viewed in the direction of the rotation axis (L1). Furthermore, the tooth profile of the driven gear (20) is set, considering a tangent angle that changes momentarily as the drive gear (10) rotates.