Composite Speed Reducer Casing for Strength and Inner Tooth Slidability
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Solution Overview
Problem
Existing speed reducer casings face a trade-off between maintaining strength and improving slidability, as forming the casing entirely of aluminum alloys degrades slidability while forming it entirely of engineering plastics compromises strength.
Innovation Solution
A speed reducer casing design where the inner tooth portion is made of a material with higher slidability and the casing body portion is made of a material with higher hardness and melting point, allowing for separate optimization of strength and slidability, with the casing body portion covering the radially outer region of the inner tooth portion and manufactured using injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the entirety of the casing is formed of an aluminum alloy to improve the strength of the casing, then the strength of the casing is improved, but the slidability of the pin grooves (inner teeth) is degraded
Solution Approach 1:
The patent applies local quality by forming the pin grooves (inner teeth) as a distinct portion with different material properties than the main casing body. Specifically, the pin grooves are formed by injection molding a resin material that provides superior slidability, while the main casing body maintains the high strength characteristics of aluminum alloy. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements.
Solution Approach 2:
The patent employs composite materials by combining aluminum alloy for the casing body with resin material for the pin grooves. The aluminum alloy provides the necessary structural strength and rigidity of the overall casing, while the resin material in the pin grooves provides enhanced slidability for the inner teeth. This composite approach allows simultaneous achievement of both strength and slidability requirements.
2Ease of operation
If the entirety of the casing is formed of an engineering plastic to improve the slidability of the pin grooves (inner teeth), then the slidability of the pin grooves is improved, but it is difficult to maintain a sufficiently high strength of the entirety of the casing
Solution Approach 1:
The patent applies local quality by forming the pin grooves (inner teeth) as a distinct portion with different material properties than the main casing body. Specifically, the pin grooves are formed by injection molding a resin material that provides superior slidability, while the main casing body maintains the high strength characteristics of aluminum alloy. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements.
Solution Approach 2:
The patent employs composite materials by combining aluminum alloy for the casing body with resin material for the pin grooves. The aluminum alloy provides the necessary structural strength and rigidity of the overall casing, while the resin material in the pin grooves provides enhanced slidability for the inner teeth. This composite approach allows simultaneous achievement of both strength and slidability requirements.
3Stability of the object's composition
If the pin grooves (inner teeth) are formed integrally with the inner peripheral surface of the speed reducer casing, then the structural integration is improved, but the slidability of the pin grooves is degraded when using high-strength materials
Solution Approach 1:
The patent applies local quality by forming the pin grooves (inner teeth) as a distinct portion with different material properties than the main casing body. Specifically, the pin grooves are formed by injection molding a resin material that provides superior slidability, while the main casing body maintains the high strength characteristics of aluminum alloy. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements.
Solution Approach 2:
The patent merges two different materials (aluminum alloy and resin) into a single integrated structure through injection molding. The resin material is injected into the mold that defines the pin groove geometry, creating a seamless integration between the casing body and the pin grooves. This merging maintains structural integrity while achieving the desired slidability through material differentiation.
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 design effectively minimizes the reduction in overall strength while enhancing the slidability of the inner teeth, ensuring both high accuracy and durability in speed reduction mechanisms.
Implementation Method 1
forming the inner tooth portion by injection molding
Data Source
AI summary
A speed reducer casing of the present invention has inner teeth on an inner periphery thereof. The speed reducer casing includes an inner tooth portion and a casing body portion, the inner tooth portion including the inner teeth, the casing body portion supporting the inner tooth portion. The inner tooth portion is formed of a material having a higher slidability than the casing body portion. The casing body portion is formed of a material having a higher hardness than the inner tooth portion.