Wave Gear Internal Tooth Surface for Graphite Lubricity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wave gear devices in robots, despite using spherical graphite cast iron for the internal gear, fail to provide sufficient lubricity due to insufficient exposure of graphite particles at the meshing positions, leading to reduced lifespan and efficiency.
Innovation Solution
A gear device design featuring an internal gear with a convex pattern and graphite particles, where the average particle diameter and separation distance between convex parts are optimized (10≤D≤40 and S−D≤20) to increase the exposure of graphite particles, enhancing lubricity and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the internal gear material is designed to provide lubrication, then lifespan can be extended, but without sufficient graphite particle exposure, the lubrication effect is insufficient and lifespan extension fails
Solution Approach 1:
The convex patterns are formed in advance on the tooth surfaces to pre-position graphite particles for optimal exposure during operation. This preliminary structuring ensures that lubrication is immediately effective when the gear begins to operate, preventing wear from the start and thereby extending the overall lifespan of the wave gear device.
Solution Approach 2:
By applying convex patterns locally at critical meshing positions, the invention ensures graphite particles are exposed where they are most needed for lubrication. This localized treatment maximizes the lubrication effectiveness at the tooth contact zones, directly contributing to reduced wear and extended device lifespan.
2Loss of energy
If graphite particles are present in the internal gear, then lubricity should be improved, but without proper exposure at meshing positions, friction remains high and efficiency is reduced
Solution Approach 1:
The convex patterns are formed beforehand to pre-position graphite particles at locations that will be exposed during meshing. This ensures that when the gear operates, graphite particles are immediately available to reduce friction, minimizing energy loss from the start of operation rather than requiring wear to first expose the particles.
Solution Approach 2:
The convex patterns create localized zones with exposed graphite particles at the tooth contact surfaces where friction occurs. By concentrating the lubrication function at these specific locations, the invention maximizes the reduction of friction loss at the meshing positions, directly improving energy efficiency.
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 optimized gear device achieves extended lifespan and improved torque transmission efficiency by increasing the probability of graphite particle exposure, reducing friction, and enhancing lubricity at the meshing positions.
Implementation Method 1
Spherical graphite cast iron includes graphite particles and can impart satisfactory lubricity by the graphite particles to a meshing position of the internal gear and the external gear
Data Source
AI summary
A gear device includes an internal gear, an external gear having flexibility configured to partially mesh with the internal gear and rotate, and a wave generator provided on an inner side of the external gear and configured to move a meshing position of the internal gear and the external gear in a circumferential direction around the rotation axis. A main material of the internal gear includes graphite particles. A tooth surface of an internal tooth of the internal gear has a convex pattern including a first convex part and a second convex part extending in a first direction having a component along the rotation axis and arranged side by side in a second direction crossing the first direction, and 10≤D≤40 and S−D≤20, wherein D [μm] is an average particle diameter of the graphite particles and S [μm] is a separation distance between the first convex part and the second convex part in the second direction.