Ringless Planetary Speed Reducer With Self-Locking Sun Gears
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Solution Overview
Problem
Conventional planetary gear reducers require multiple stages for high-ratio deceleration or speed increase, are costly to manufacture due to the need for a ring gear, and lack a self-locking function, making them inconvenient for applications requiring reversal prevention.
Innovation Solution
A speed reducer design without a ring gear, utilizing a carrier with first, second, and third planetary gears supported at different locations, where the difference in teeth between sun gears enables self-locking and various gear speed ratios, allowing for easy control and mass production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ring gear is provided in a typical planetary gear reducer, then the structure is complete and can achieve speed reduction, but manufacturing costs increase and manufacturing difficulty increases
Solution Approach 1:
The patent removes the ring gear from the planetary gear reducer structure, extracting this component entirely. The speed reduction function is achieved through alternative arrangements of sun gears and planetary gears with different tooth counts, eliminating the need for a ring gear and thereby reducing manufacturing complexity and cost.
Solution Approach 2:
The sun gears are designed to serve multiple functions: they act as both driving and driven elements, and by varying their tooth counts, they can achieve different speed reduction ratios. This multi-functionality replaces the traditional role of the ring gear in determining speed ratios.
2Reliability
If multiple stages of gears are used to achieve large deceleration, then the speed reduction ratio increases, but the volume and weight of the speed reducer increase
Solution Approach 1:
The patent employs a nested arrangement where planetary gears are positioned within the space between sun gears, and multiple planetary gears are arranged concentrically. This nesting allows multiple gear stages to be compacted into a single reduced space, achieving large deceleration ratios without proportionally increasing volume.
Solution Approach 2:
The patent utilizes the radial dimension by arranging multiple planetary gears at different radii around the sun gears. This dimensional arrangement allows multiple gear meshing stages to occur simultaneously in different radial zones, achieving compound deceleration in a compact configuration rather than requiring sequential axial stacking.
3Ease of manufacture
If the number of planetary gears is reduced to lower manufacturing costs, then manufacturing cost decreases, but strength decreases
Solution Approach 1:
The patent creates an asymmetric load distribution by positioning planetary gears at specific angular intervals that are not uniformly distributed. This asymmetric arrangement optimizes the load path through the gear train, allowing fewer planetary gears to carry the same total load more efficiently, thereby maintaining strength while reducing component count and manufacturing cost.
Data Source
AI summary
Proposed are a speed reducer having a self-locking function without a ring gear, and a self-locking method of the speed reducer. Particularly, the speed reducer is characterized in that first, second and third planetary gears are supported at different locations on one side of a carrier, which is an input side, so as to be able to rotate and revolve and be disposed in n sets, and when fixing any one of a first sun gear and a second sun gear and switching one remaining sun gear into an input side and rotating the same, speed is not increased due to a self-locking function and a speed increase ratio is zero (a stationary state in which the sun gear used as the input side cannot rotate), thereby resulting in self-locking which is a non-operating state.