Nested Planetary Gear Driving Module for Compact Motion Assist
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Solution Overview
Problem
Existing motion assist apparatuses face challenges in achieving miniaturization, reduced weight, and high reduction gear ratios, which are essential for comfortable and efficient human body integration.
Innovation Solution
A driving module design incorporating a gear train with a first and second planetary gear set, where the second planetary gear has a larger diameter and more teeth than the first, and is integrated with a reduction gear system to minimize volume and weight while achieving a high gear reduction ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional reduction gear system is used, then the gear ratio can be achieved, but the volume and weight of the driving module increase
Solution Approach 1:
The patent applies nesting by placing the first planetary gear set inside the driving source housing and the second planetary gear set outside, with the second gear set nested around the first. This concentric arrangement allows both gear sets to occupy overlapping spatial zones, significantly reducing the overall volume of the driving module while maintaining the required reduction gear ratio.
Solution Approach 2:
The reduction gear system is segmented into two separate planetary gear sets with different functions. The first planetary gear set is positioned inside the driving source to reduce volume, while the second planetary gear set is positioned outside to achieve the required reduction ratio. This segmentation allows optimization of each gear set's location and size independently.
2Volume of moving object
If the gear train is miniaturized, then the volume is reduced, but the reduction gear ratio decreases
Solution Approach 1:
The patent merges two planetary gear sets into a single integrated transmission system. The first planetary gear set inside the driving source and the second planetary gear set outside work together in series to achieve the cumulative reduction effect. This combination allows the system to maintain high reduction gear ratio while keeping the overall volume compact through the nested arrangement.
Solution Approach 2:
The patent utilizes the radial dimension by arranging the two planetary gear sets at different radial positions - one inside the driving source housing and one outside. This three-dimensional spatial arrangement allows both gear sets to contribute to the reduction ratio without increasing the axial length or overall footprint of the driving module.
3Force
If a high reduction gear ratio is achieved, then the torque is increased, but the weight of the driving module increases
Solution Approach 1:
The patent replaces a single large planetary gear set with two smaller planetary gear sets arranged in series. This substitution achieves the same torque multiplication effect through combined gear ratios while reducing the overall weight, as multiple smaller gears are lighter than one large gear set capable of providing the same reduction ratio.
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 design allows for a compact and lightweight motion assist apparatus that reduces the load on the human body and efficiently transmits power with a high reduction gear ratio, enhancing user comfort and functionality.
Implementation Method 1
a sun gear coupled to the driving source to rotate by power transmitted from the driving source; and a first planetary gear engaged with the sun gear to revolve around the sun gear
Implementation Method 2
a second planetary gear coupled onto the first planetary gear at a side opposite to the driving source. Also, the first planetary gear revolves around the axis by the driving source, and the second planetary gear is engaged with the ring gear to revolve around the axis together with the first planetary gear
Implementation Method 3
the second planetary gear is engaged with the ring gear to revolve around the axis together with the first planetary gear
Data Source
AI summary
Provided is a driving module including: a driving source for generating power; a ring gear disposed coaxially with the driving source; and a gear train disposed between the driving source and the ring gear. Here, the gear train includes: a first gear set of which at least a portion is inserted into the driving source; and a second gear set, the first gear set includes: a sun gear coupled to the driving source to rotate by power transmitted from the driving source; and a first planetary gear engaged with the sun gear to revolve around the sun gear, the second gear set includes a second planetary gear fixed and coupled onto the first planetary gear at a side opposite to the driving source, and the second planetary gear is engaged with the ring gear.