Planetary Gear Ratio Switching Using Magnetic Braking Force
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Solution Overview
Problem
Existing speed reduction ratio automatic switching devices are prone to performance changes due to environmental conditions and degradation over time, leading to unstable switching points.
Innovation Solution
A speed reduction ratio automatic switching device utilizing a planetary gear mechanism with helical gears and a magnet as the resisting element, which generates a magnetic braking force to switch the speed reduction ratio based on load changes, ensuring stable operation regardless of environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If viscous resisting substance is used to generate thrust force between internal gear and planetary gears, then speed reduction ratio switching is achieved, but switching point stability deteriorates due to environmental changes and degradation over time
Solution Approach 1:
The patent replaces the mechanical viscous resisting substance system with a magnetic field-based resisting element system. The magnet generates magnetic braking force without physical contact, eliminating degradation issues associated with viscous substances while maintaining the thrust force generation function for speed reduction ratio switching.
Solution Approach 2:
The patent changes the physical state and properties of the resisting element from a viscous substance to a magnetic field. This parameter change allows the resisting force to be generated through magnetic interaction rather than mechanical friction, improving stability and durability without sacrificing the switching function.
2Force
If viscous resisting substance is provided between internal gear and planetary gears, then thrust force is generated for switching, but performance changes due to temperature and degradation occur
Solution Approach 1:
The patent substitutes the temperature-sensitive viscous resisting substance with a temperature-insensitive magnet. The magnetic field strength remains stable across temperature variations, ensuring consistent thrust force generation for speed reduction ratio switching regardless of environmental temperature changes.
3Extent of automation
If conventional resisting elements are used, then speed reduction switching is achieved, but switching point drifts over time due to degradation
Solution Approach 1:
The magnet as a resisting element requires no maintenance or replacement, providing self-service operation over extended periods. The magnetic field remains stable without degradation, ensuring the automatic switching function operates reliably at the designed switching point throughout the device's service life.
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 device maintains a stable switching point over years, unaffected by temperature changes or degradation, allowing for reliable automatic switching of the speed reduction ratio.
Implementation Method 1
the resisting element comprises a magnet provided between the internal gear and the carrier made of a hysteresis material
Implementation Method 2
the carrier made of a hysteresis material, the carrier is coupled to the output shaft
Data Source
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AI summary
A speed reduction ratio automatic switching device (10) includes a planetary gear mechanism (16). The planetary gear mechanism (16) includes a sun gear (32) provided for an input shaft (30), planetary gears (34a, 34b, 34c) in mesh with an outer circumferential side of the sun gear (32), an internal gear (36) in mesh with an outer circumferential side of the planetary gears (34a, 34b, 34c), and first and second carriers (38, 40) made of a semi-rigid magnetic material. The first and second carriers (38, 40) support the planetary gears (34a, 34b, 34c) in a rotatable manner, and rotate together with the planetary gears (34a, 34b, 34c) along with revolution of the planetary gears (34a, 34b, 34c). Each of the sun gear (32), the planetary gears (34a, 34b, 34c) and the internal gear (36) is a helical gear. First and second magnets (52, 54) for generating a thrust force in an axial direction are provided between the first and second carriers (38, 40) and the internal gear (36).