Rigid Internal Gear Manufacturing via Powder Forging
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Solution Overview
Problem
The existing manufacturing methods for rigid internal gears in wave gear devices result in heavy components due to the use of strong and abrasion-resistant materials like iron or copper, compromising the lightweight advantage of the gear device, and require secure joining of components to transmit torque effectively.
Innovation Solution
A method involving the use of aluminum alloy powders for forming the gear main body and internal teeth portions, integrated through powder forging or hot extrusion, where the harder, more abrasion-resistant second alloy is used for the teeth portion and a lighter first alloy for the main body, eliminating the need for additional joining methods like bolts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If iron or copper materials are used for the rigid internal gear to ensure strength and abrasion resistance, then the gear achieves high durability, but the device weight increases significantly
Solution Approach 1:
The patent applies local quality by using different materials for different parts of the gear: iron or copper powder for the internally toothed portion requiring strength and abrasion resistance, and aluminum alloy powder for the gear main body portion where weight reduction is prioritized. This localized material differentiation resolves the contradiction between durability and weight.
Solution Approach 2:
The patent uses composite materials by combining iron or copper powder with aluminum alloy powder in a single forging process. The resulting composite gear structure integrates the high strength and abrasion resistance of iron/copper in the toothed portion with the lightweight properties of aluminum alloy in the main body, simultaneously achieving both durability and weight reduction.
2Reliability
If the internally toothed portion and gear main body are manufactured as separate rings and integrally joined, then the gear achieves optimized material distribution, but the manufacturing complexity and joining difficulty increase
Solution Approach 1:
The patent merges the manufacturing of the internally toothed portion and gear main body into a single powder forging process. By placing both preformed rings or discs into a forging die and applying pressure, the components are integrally joined in one operation, eliminating the need for separate joining processes and reducing manufacturing complexity.
Solution Approach 2:
The patent applies preliminary action by preforming the gear main body ring and internal teeth-forming ring or disc separately before the final forging step. This allows optimal material distribution to be established in advance, while the subsequent single forging operation completes the integration without requiring complex joining procedures.
3Weight of moving object
If aluminum alloy powder is used for the gear main body to reduce weight, then the device achieves lightweight advantage, but the torque transmission capability between components decreases
Solution Approach 1:
The patent uses composite materials to resolve the torque transmission issue. The iron or copper powder embedded within the aluminum alloy matrix during forging creates strong interfacial bonding and mechanical interlocking, enabling effective torque transmission from the aluminum main body to the iron/copper toothed portion while maintaining the lightweight advantage.
Solution Approach 2:
The patent utilizes the spherical shape of powder particles to improve torque transmission. The rounded geometry of iron or copper powder particles embedded in the aluminum alloy allows for better stress distribution and mechanical interlocking under torsional loads, enhancing the torque transmission capability of the composite 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
This approach enables the secure integration of lightweight, durable, and high-strength rigid internal gears with improved torque transmission characteristics, maintaining the lightweight advantage of wave gear devices while ensuring high durability.
Implementation Method 1
the internal teeth-forming ring or disc is fitted inside the gear main body ring and these are integrated by powder forging
Implementation Method 2
an internal teeth-forming ring or disc for forming the internally toothed portion is preformed using a second aluminum alloy powder
Data Source
AI summary
The present invention provides a method for manufacturing a rigid internal gear for a wave gear device comprising an internally toothed portion and a gear main body portion comprised of different materials. In this method, a gear main body ring for forming a gear main body portion is preformed using a first aluminum alloy powder; an internal teeth-forming ring is preformed using a second aluminum alloy powder that has lower processability, is less durable, has higher abrasion resistance, and is harder than the first aluminum alloy powder; the internal teeth-forming ring is fitted inside the gear main body ring and the assembly is integrated by powder forging; and the resulting ring-shaped forging is subjected to post-processing, including cutting teeth. The gear main body portion and internally toothed portion are securely integrated by powder forging, and a lightweight rigid internal gear with high durability can therefore be obtained.