Compact Speed Reducer With Movable Internal Gear for High Reduction
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Solution Overview
Problem
Existing speed reducers with high reduction ratios are too large and complex, making them unsuitable for miniaturized and refined equipment, and they face manufacturing and operational challenges due to the need for precise tooth profiles and interference elimination.
Innovation Solution
A compact speed reducer design featuring a drive gear, two planetary gears, a fixed internal gear, and a movable internal gear, where the planetary gears are hollow rings with deformation elasticity, allowing for a high reduction ratio without the need for a planetary carrier and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional compound planetary gears are used to achieve high reduction ratio, then the reduction ratio is improved, but the device size and complexity increase significantly
Solution Approach 1:
The patent merges the functions of multiple planetary gear sets into a single planetary gear system by utilizing a movable internal gear with variable number of teeth. This integration eliminates the need for separate planetary carriers and multiple gear sets, achieving high reduction ratio while reducing device complexity and size.
Solution Approach 2:
The patent introduces a movable internal gear whose number of teeth can be dynamically adjusted or selected. This dynamic characteristic allows the system to achieve different reduction ratios without changing the overall structure, thereby maintaining compact configuration while providing high reduction capability.
2Ease of manufacture
If standard involute tooth profile is used for internal gear, then manufacturing is simplified, but interference with planetary gears occurs preventing smooth operation
Solution Approach 1:
The patent applies local quality modification to the internal gear tooth profile. Instead of using a uniform standard involute profile throughout, the tooth profile is locally modified in specific regions to eliminate interference with planetary gears while maintaining manufacturability. This localized adjustment ensures smooth operation without sacrificing ease of manufacture.
3Productivity
If multiple planetary gear sets are combined to increase reduction ratio, then the reduction ratio is improved, but the axial length increases making miniaturization difficult
Solution Approach 1:
The patent employs a nested configuration where the movable internal gear is positioned within the space defined by the fixed internal gear and planetary gears. This nesting allows the high reduction ratio mechanism to be compacted axially, reducing the overall length while maintaining the required reduction capability for miniaturized applications.
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 achieves a high reduction ratio in a compact configuration, simplifies assembly, reduces backlash, and provides precise transmission and accurate positioning, while also enabling self-locking and reducing power loss and noise.
Implementation Method 1
The planetary gears are each in the form of a hollow ring. The planetary gears extend into the movable internal gear and mesh with the movable internal gear, respectively
Data Source
AI summary
A speed reducer includes a drive gear, at least two planetary gears and a fixed internal gear that are arranged in sequence in an inside-out direction and mesh with one another. A movable internal gear is coaxially arranged beside the fixed internal gear. The number of teeth of the movable internal gear is different from the number of teeth of the fixed internal gear. The planetary gears extend into the movable internal gear and mesh with the movable internal gear, respectively. The drive gear is arranged along an axis for driving the planetary gears to rotate between the drive gear and the fixed internal gear. Due to the difference in the number of teeth between the fixed internal gear and the movable internal gear, when the planetary gears are rotated, the movable internal gear is pushed and moved by the planetary gears to perform a reduction output.