Geared Speed Reducing Unit with Nested Planetary Modules
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Solution Overview
Problem
Existing geared speed reducing units face challenges in achieving a high speed reducing ratio while maintaining a compact and simple structure, often requiring complex designs and expensive cycloid gears, which limits flexibility and increases manufacturing costs.
Innovation Solution
A geared speed reducing unit with a coaxial arrangement of first and second rotary shafts, featuring internal contact type planetary gear sets with a fixed first sun gear and adjustable gear ratios between sun and ring gears, allowing for a wide range of speed reducing ratios without the need for complex structures or expensive cycloid gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If complex planetary gear units or magical planetary gear speed reducing mechanisms are used to achieve large reduction ratios, then the speed reducing ratio is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The planetary gear set is divided into multiple independent planetary modules, each consisting of a sun gear, planet gears, and ring gear. These modules are arranged in series to achieve cumulative reduction ratios while maintaining a relatively simple overall structure compared to traditional complex planetary mechanisms.
Solution Approach 2:
Multiple planetary modules are nested within each other radially, with each subsequent module positioned inside the previous one. This nested arrangement allows for compact design and achieves large reduction ratios without proportionally increasing the overall device size or complexity.
2Productivity
If cycloid gears are used to achieve high reduction ratios, then the speed reducing ratio is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive cycloid gears with standard involute spur gears and helical gears that are cheaper to manufacture using conventional gear cutting processes. The design accepts slightly larger size in exchange for significantly reduced manufacturing costs and improved ease of production.
Solution Approach 2:
The patent changes the gear type parameter from cycloid to involute/helical gears, and adjusts the number of teeth and module parameters to achieve the desired reduction ratio. This parameter optimization allows using standard, cost-effective gear manufacturing processes while maintaining high reduction ratios.
3Productivity
If the number of planetary modules is increased to achieve larger reduction ratios, then the speed reducing ratio is improved, but the radial size of the gear unit increases
Solution Approach 1:
Multiple planetary modules are arranged in a nested configuration where each module is positioned radially inside the previous one. This allows the gear unit to achieve large reduction ratios by stacking modules in the radial direction rather than increasing the overall radial footprint, effectively utilizing the axial space.
Solution Approach 2:
Instead of arranging planetary modules side-by-side in the radial plane, the patent transitions to a three-dimensional nested arrangement where modules are stacked along the axial direction. This dimensional change allows for compact radial size while achieving cumulative reduction ratios through the series arrangement of multiple modules.
4Ease of manufacture
If standard spur gears are used instead of cycloid gears, then the manufacturing cost is reduced, but the achievable reduction ratio is limited
Solution Approach 1:
The patent combines multiple planetary modules with standard spur gears and helical gears in a series configuration. Each module provides a moderate reduction ratio, and the cumulative effect of stacking multiple modules achieves overall high reduction ratios comparable to or exceeding cycloid gear systems, while maintaining the manufacturing advantages of standard 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 solution enables a high speed reducing ratio with a simplified structure, allowing for easy adjustment of gear ratios and reduced manufacturing costs, while stabilizing rotations with counterbalance weights, facilitating downsizing of geared motors and increased flexibility in design.
Implementation Method 1
stabilizing rotations with counterbalance weights
Implementation Method 2
stabilizing rotations with counterbalance weights
Implementation Method 3
internal contact type planetary gear sets with a fixed first sun gear and adjustable gear ratios between sun and ring gears
Implementation Method 4
an eccentric carrier that is arranged around the common rotational axis to support the third gear and the fourth gear such that the third gear and the fourth gear rotate around an eccentric axis offset from the common rotational axis and revolve around the common rotational axis
Data Source
AI summary
A compact geared speed reducing unit having a simple structure that can establish a large speed reducing ratio. The geared speed reducing unit comprises: a first rotary shaft and a second rotary shaft arranged coaxially; a fixed first sun gear; a second sun gear rotated integrally with the second rotary shaft; a first ring gear meshing with the first sun gear; a second ring gear rotated integrally with the first ring gear and meshed with the second sun gear; and an eccentric carrier supporting the ring gears such that the ring gears rotate around an eccentric axis and revolve around a common rotational axis of the rotary shafts. A gear ratio between the first sun gear and the first ring gear and a gear ratio between the second sun gear and the second ring gear are set to different values.