Internal Meshing Gear Pair Layout for Low-Friction Tooth Contact
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Solution Overview
Problem
Conventional gear design methods limit design freedom for gear characteristics such as friction loss and abrasion, as they primarily determine the tooth profile curve of one gear first, restricting the optimization of gear pairs.
Innovation Solution
The approach involves determining the contact point locus and pitch point as conditions for defining gear curves, allowing for higher design freedom and optimizing gear efficiency and reducing abrasion by positioning the pitch point radially inside the tooth tip circles and ensuring the contact point locus is within a specific angle range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional gear design methods are used to determine tooth profile curves, then the design process is simplified, but design freedom for gear characteristics such as friction loss and abrasion is limited
Solution Approach 1:
The patent inverts the conventional design approach by not starting with the tooth profile curve of one gear, but rather determining the contact point locus and pitch point first. This inversion allows for greater design freedom in optimizing gear characteristics such as friction loss and abrasion, while still enabling a systematic design process.
Solution Approach 2:
The patent changes the fundamental parameters used in gear design from tooth profile curves to contact point locus and pitch point positioning. By controlling the position of the pitch point radially inside the tooth tip circles and defining the contact point locus within specific angle ranges, the design enables optimization of gear meshing characteristics including reduced friction and abrasion.
2Reliability
If the pitch point is positioned at conventional locations, then standard gear meshing is achieved, but gear efficiency is reduced and abrasion increases
Solution Approach 1:
The patent optimizes gear efficiency and reduces abrasion by changing the positional parameters of the pitch point and contact point locus. Specifically, the pitch point is positioned radially inside the external and internal tooth tip circles, and the contact point locus is constrained within angle ranges of 0 to π/2 radians from the gear center line, achieving co-rotating meshing that reduces friction loss.
Solution Approach 2:
The patent converts the potential harm of non-standard pitch point positioning into benefit by deliberately placing the pitch point inside the tooth tip circles. This unconventional positioning, when combined with proper contact point locus design, creates co-rotating meshing that reduces abrasion and improves lubrication, turning a potentially problematic configuration into an advantageous one.
Data Source
AI summary
An internal meshing type gear device includes: an internal gear; and an external gear that meshes with the internal gear, in which, when a straight line passing through an external gear center and an internal gear center is defined as a gear center line, a pitch point between the external gear and the internal gear is positioned radially inside an external tooth tip circle and an internal tooth tip circle, an intersection point between a normal line to a contact point locus between the external gear and the internal gear and the gear center line is positioned between the pitch point and the external gear center, and the contact point locus is positioned in a meshing region between the external and internal tooth tip circles within an angle range in which an angle centered on the pitch point from the gear center line is 0 to π/2 [rad].