Internal Meshing Planetary Gear Structure Without Inner Rollers
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Solution Overview
Problem
The miniaturization of internal-meshing planetary gear devices is hindered by the difficulty in miniaturizing the inner pin holes due to the need for inner rollers to reduce frictional resistance, leading to challenges in centering precision and increased size in the axial direction.
Innovation Solution
The design eliminates the need for inner rollers by allowing inner pins to self-rotate within the inner pin holes, reducing frictional resistance and enabling miniaturization by using a support body to constrain and center the inner pins, thereby improving centering precision and reducing the device's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If inner rollers are used to reduce frictional resistance in inner pin holes, then frictional resistance is reduced, but the device size increases in the axial direction and miniaturization is hindered
Solution Approach 1:
The invention extracts and eliminates the inner rollers from the system, allowing the inner pins to self-rotate directly within the inner pin holes. This removal of unnecessary components reduces the axial direction size while the self-rotation mechanism maintains sufficient friction reduction for the application.
Solution Approach 2:
The inner pins are designed to self-rotate within the inner pin holes without requiring separate inner rollers. The pins themselves perform the rotation function, eliminating the need for additional friction-reducing components and enabling miniaturization in the axial direction.
2Ease of operation
If inner rollers are used to reduce frictional resistance, then rotation is facilitated, but centering precision becomes more difficult to maintain
Solution Approach 1:
By removing the inner rollers, the invention eliminates the centering issues associated with them. The direct self-rotation of inner pins within the pin holes provides inherent centering stability while still facilitating rotation through the self-rotation mechanism.
Solution Approach 2:
The inner pins self-center through their own rotational motion within the pin holes, eliminating the need for separate centering mechanisms. This self-centering capability maintains precision while facilitating smooth rotation.
3Strength
If the input shaft outer diameter is increased to fix an object member, then the object member can be securely fixed, but miniaturization of the planetary gear device is hindered
Solution Approach 1:
The bushing with the fixing structure is nested on the input shaft, allowing the object member to be fixed without increasing the shaft's outer diameter. The bushing provides the necessary fixing capability while maintaining a compact overall structure that enables miniaturization.
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
This configuration allows for the miniaturization of the planetary gear device while maintaining efficient rotation transmission and reducing the risk of vibration and transmission efficiency losses, achieving a compact and precise gear mechanism.
Implementation Method 1
reducing frictional resistance
Implementation Method 2
The input shaft swings the planetary gear eccentrically
Data Source
AI summary
An internal meshing planetary gear apparatus and a robotic joint device. The internal meshing planetary gear apparatus includes an internally toothed gear, a planetary gear, a plurality of inner pins, an eccentric shaft which acts as an input shaft, and a bushing. The plurality of inner pins is respectively inserted into a plurality of inner pin holes formed in the planetary gear, and is configured to revolve in the inner pin holes while rotating relative to the internally toothed gear about a rotation axis. The eccentric shaft is configured to cause the planetary gear to oscillate eccentrically. The bushing includes a fixing structure configured to fix an object member, and the bushing is combined with the eccentric shaft and configured to rotate together with the eccentric shaft.