Powder Metal Ring Gear Structure for Improved Concentricity
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Solution Overview
Problem
Conventional ring gears in two-stage gear reduction devices require secondary machining and mechanical connection, leading to high costs and potential eccentricity due to fabrication or assembly errors.
Innovation Solution
A ring gear comprising integrally formed first and second annular bodies with teeth, manufactured from powder metal in a single mold cavity, eliminating the need for secondary machining and improving concentricity by forming a monolithic structure with helical and straight teeth configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If ring gears are separately formed and connected via fasteners, then assembly flexibility is improved, but manufacturing precision deteriorates due to eccentricity between the two ring gears
Solution Approach 1:
The patent merges two separately formed ring gear parts into a single integrally formed ring gear structure. The first and second ring gear parts are formed as one piece through powder metallurgy in a single mold cavity, eliminating the need for separate manufacturing and mechanical connection. This resolves the technical contradiction by prioritizing manufacturing precision (concentricity) over assembly flexibility, as the integral structure inherently prevents eccentricity between parts.
2Ease of manufacture
If ring gears are separately formed with connection portions, then ease of manufacture is improved, but device complexity increases due to secondary machining and mechanical connection
Solution Approach 1:
The patent combines multiple manufacturing operations into a single powder metallurgy process. The mold cavity includes first and second forming regions that simultaneously form both ring gear parts with their respective teeth in one operation. This eliminates secondary machining and mechanical connection steps, resolving the contradiction by maintaining ease of manufacture while reducing device complexity through process integration.
Solution Approach 2:
The single mold cavity serves multiple functions: it forms both ring gear parts, creates their respective teeth patterns, and positions them relative to each other all in one operation. This multi-functionality resolves the technical contradiction by simplifying the overall manufacturing process while reducing structural complexity compared to separate manufacturing and assembly operations.
3Productivity
If ring gears are separately formed and assembled, then productivity is improved through parallel manufacturing, but manufacturing precision deteriorates due to assembly errors
Solution Approach 1:
The patent merges the manufacturing of two ring gear parts into a single powder metallurgy operation within one mold cavity. This simultaneous formation eliminates assembly operations entirely, resolving the contradiction by achieving both high productivity (through single-step manufacturing) and high precision (through inherent positional accuracy of the integral structure).
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 solution reduces manufacturing costs, eliminates eccentricity, and enhances the concentricity of the ring gear parts, resulting in a more efficient and cost-effective gear device with improved assembly precision.
Implementation Method 1
The first ring gear part and the second ring gear part are integrally formed from powder metal
Data Source
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AI summary
The present invention provides a ring gear (100) and a gear reduction device. The ring gear (100) includes a one-piece annular body made from powder metallurgy material, and a first ring gear part and a second ring gear part formed on a surface of the annular body. The first ring gear part and the second ring gear part are arranged along an axial direction of the annular body. The ring gear (100) has a density less than 92% of its theoretical density and a mass of 6.0 to 8.0 grams per cubic millimeter. The present invention further provides a mold for manufacturing the ring gear (100). The ring gear (100) of the present invention includes two ring gear parts (10, 20) integrally formed at once, and the two ring gear parts (10, 20) have improved concentricity.