Extruded Ring Gear Shaping for Precision and Strength
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Solution Overview
Problem
Conventional methods for manufacturing ring gears, such as cutting or powder metallurgy, are either expensive and time-consuming or result in gears with low mechanical strength and geometrical precision.
Innovation Solution
A method involving metal extrusion to form a hollow tube with gear teeth, using a shaping tool with tool teeth to exert a radially outward force and fix the outer perimeter, followed by anodizing and refining the gear teeth, and integrating the ring gear into a planetary gear system with plastic planet gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional cutting methods are used to manufacture ring gears, then manufacturing precision can be achieved, but the process becomes expensive and time-consuming
Solution Approach 1:
The invention changes the manufacturing parameter from conventional cutting methods to metal extrusion process. The extrusion process forms gear teeth by forcing metal through a die with gear tooth profiles, fundamentally changing how gear teeth are created. This parameter change enables high precision gear teeth to be formed during the extrusion process itself, eliminating subsequent costly and time-consuming cutting operations while maintaining manufacturing precision.
2Productivity
If powder metallurgy is used to manufacture ring gears, then production cost and time are reduced, but mechanical strength and geometrical precision deteriorate
Solution Approach 1:
The invention changes the material processing parameter from powder metallurgy to solid metal extrusion. By using solid metal extrusion, the gear teeth are formed from solid metal stock rather than compacted powder, inherently providing superior mechanical strength. The extrusion process maintains metallurgical continuity and grain structure integrity, eliminating the weakness associated with powder metallurgy while preserving production efficiency.
Solution Approach 2:
The invention employs composite material structure by combining the extruded metal tube material with precisely formed gear teeth geometry. The integration of gear teeth directly into the extruded tube creates a composite structure where the base metal provides strength and the formed teeth provide precise geometrical engagement, achieving both high mechanical strength and geometrical precision simultaneously.
3Productivity
If metal extrusion is used to form ring gears, then production cost and time are reduced, but initial manufacturing precision may be insufficient without additional shaping
Solution Approach 1:
The invention applies preliminary shaping action during the extrusion process itself. The extrusion die is designed with precise gear tooth profiles that pre-form the gear teeth geometry as the metal is being extruded. This preliminary action ensures that gear teeth are formed with correct geometry during the primary forming process, eliminating the need for subsequent precision cutting or machining operations.
Solution Approach 2:
The invention introduces an intermediary shaping tool or mandrel that works in conjunction with the extrusion process. This intermediary tool helps refine the outer perimeter and gear tooth geometry during or immediately after extrusion, acting as a mediator between the rough extruded form and the final precision requirement, thereby achieving high manufacturing precision without sacrificing production 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
This method enables the production of high-quality ring gears with improved mechanical strength and precision at a lower cost, suitable for use in planetary gear systems, enhancing operational efficiency and reducing production time.
Implementation Method 1
the tube being a hollow tube formed by extrusion
Implementation Method 2
The method may further comprise anodizing the gear teeth
Data Source
AI summary
There is provided a method of forming a ring gear, including providing a tube having an inner surface comprising gear teeth, the tube being a hollow tube formed by extrusion. The method also includes inserting a shaping tool into the tube, the shaping tool having tool teeth to mate with the gear teeth, and extended and retracted configurations. The shaping tool may be inserted into the tube in its retracted configuration. Moreover, the method includes extending the shaping tool into its extended configuration to cause the tool teeth to mate with the gear teeth and to exert a radially outward force on the tube. Furthermore, the method includes fixing a shape of an outer perimeter of the tube, retracting the shaping tool into its retracted configuration to reduce the radially outward force exerted by the shaping tool on the tube, and removing the shaping tool from the tube.