Webbed Brace Powertrain Stiffness NVH Reduction
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Solution Overview
Problem
The existing powertrain systems in vehicles with all-wheel drive capability experience noise, vibration, and harshness (NVH) due to torque generation and transfer, leading to driver discomfort and joint fatigue, particularly when the front axle is mounted rearward, requiring a solution to enhance stiffness and reduce these issues.
Innovation Solution
Incorporating a webbed brace directly fastened to the transmission case, transfer case, and front axle housing to form a powerplant system, which increases the bending frequency and stiffness within a predefined range, thereby reducing NVH and dynamic motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the front axle is mounted more rearward adjacent the transmission case, then the packaging and alignment are improved, but the structural strength and stiffness to support the front axle are insufficient
Solution Approach 1:
The patent combines the transmission case, transfer case, and front axle housing into an integrated powerplant system, merging multiple structural components into a unified assembly that shares load paths and structural support, thereby achieving both compact packaging and enhanced structural strength
Solution Approach 2:
The patent introduces a webbed brace structure that adds dimensional complexity to the powerplant assembly, creating a three-dimensional bracing network that reinforces the structure without increasing the overall footprint, thus maintaining compact packaging while improving structural strength
2Device complexity
If traditional powertrain mounting is used, then the device complexity is low, but noise, vibration, and harshness increase due to insufficient stiffness
Solution Approach 1:
The patent modifies the structural parameters of the powerplant system by introducing webbed bracing elements with specific geometric configurations, changing the stiffness characteristics and natural frequencies of the assembly to move away from resonance with engine and drivetrain excitation frequencies, thereby reducing vibration and noise
Solution Approach 2:
The patent employs a composite structural approach by combining rigid casting materials for the housing components with strategically placed webbed brace elements, creating a composite structure that optimizes both stiffness and damping properties to reduce NVH while maintaining manufacturing feasibility
3Object-affected harmful factors
If a webbed brace is added to increase stiffness and bending frequency, then NVH is reduced, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The webbed brace structure is integrated into the existing powerplant housing components during the casting process, merging the brace elements with the transmission case, transfer case, and front axle housing into unified castings, which eliminates separate manufacturing and assembly steps for the bracing elements
Solution Approach 2:
The webbed brace geometry is optimized with specific web patterns and thickness parameters that can be directly formed during the casting process, allowing complex bracing structures to be manufactured using conventional casting techniques without requiring additional machining or assembly operations
Data Source
AI summary
A powertrain includes a transmission case, a transfer case, a front axle housing, and a webbed brace. The transfer case and front axle housing are directly fastened to the transmission case. The webbed brace is directly fastened to the transmission case, the transfer case, and the front axle housing to form a powerplant system. The webbed brace is configured such that a bending frequency of the powerplant system falls within a predefined range.