Multi-Material Gear Assembly for Lower Weight and NVH
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Solution Overview
Problem
Conventional gear assemblies are heavy and exhibit suboptimal noise, vibration, and harshness (NVH) characteristics due to their uniform material composition, which limits their performance in applications requiring weight reduction and improved NVH characteristics.
Innovation Solution
A multi-material gear assembly is designed with a ring gear made of stainless steel and a core composed of cast iron or aluminum composite materials, which are joined using methods such as press-fitting, welding, or over-molding, to achieve a lightweight and durable structure with enhanced NVH performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional gear assemblies are made from uniform material composition, then structural integrity is maintained, but weight reduction and NVH performance improvement are limited
Solution Approach 1:
The gear assembly uses different materials for different components: the ring gear is made of stainless steel for strength, while the core is made of cast iron or aluminum composite materials for weight reduction. This local differentiation of material properties allows each component to optimize its characteristics for its specific functional requirements, achieving both weight reduction and maintained structural integrity.
Solution Approach 2:
The invention employs composite material construction by combining dissimilar materials (stainless steel ring gear with cast iron or aluminum composite core) through joining methods such as press-fitting, welding, or over-molding. This composite approach enables the gear assembly to achieve properties that neither material could provide alone, specifically combining the strength of steel with the weight advantages of lighter materials.
2Object-affected harmful factors
If conventional gear assemblies use uniform material composition, then manufacturing simplicity is maintained, but NVH characteristics are suboptimal
Solution Approach 1:
The core is specifically designed with different material properties than the ring gear to provide noise and vibration damping. The cast iron or aluminum composite material in the core absorbs and dampens vibrations and noise generated during gear operation, while the stainless steel ring gear maintains its strength for load-bearing functions. This localized functional differentiation addresses NVH characteristics without requiring complexity throughout the entire assembly.
Solution Approach 2:
The combination of dissimilar materials (steel ring gear with cast iron or aluminum core) creates a composite structure where each material contributes its advantageous properties. The lighter core materials provide inherent damping characteristics that reduce noise and vibration, while the steel ring gear provides structural strength. This composite approach improves NVH performance while maintaining manufacturing feasibility through established joining techniques.
3Weight of moving object
If multi-material construction is used, then weight savings and NVH improvement are achieved, but manufacturing complexity increases
Solution Approach 1:
The gear assembly is segmented into distinct components (ring gear and core) that can be manufactured separately using optimal processes for each material, then joined together. This segmentation allows each component to be optimized for its material properties and manufacturing process, with the ring gear made from stainless steel and the core from cast iron or aluminum composite materials, reducing overall manufacturing complexity compared to attempting to create a monolithic multi-material part.
Solution Approach 2:
The invention merges dissimilar materials (stainless steel ring gear with cast iron or aluminum composite core) through conventional joining methods such as press-fitting, welding, or over-molding. These joining techniques are well-established in manufacturing, allowing the multi-material assembly to be produced using existing manufacturing capabilities without requiring complex or specialized processes, thus maintaining ease of manufacture while achieving weight savings.
Data Source
AI summary
Examples of a multi-material gear assembly include a multi-material gear assembly including a ring gear including a first material, the ring gear having an inner diameter and an outer diameter, and a core coupled to the inside diameter of the ring gear, the core including a second material that is different from the first material. In an example of the above aspect, the first material of the ring gear includes stainless steel. In another example, the second material of the core includes one cast iron and an aluminum composite material. In a further example, the outer diameter of the ring gear includes a plurality of helical gear teeth. In yet another example, the inner diameter of the ring gear has a smooth surface compared to the outer diameter.