Parallel Pinion Drive Axle System for NVH Reduction
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Solution Overview
Problem
Existing tandem axle configurations in vehicles face inefficiencies due to limitations in torque transmission and gear configurations, leading to issues with noise, vibration, and harshness (NVH), as well as potential frictional drag and operational inefficiencies.
Innovation Solution
A drive axle system with a first and second drive axle assembly, each featuring distinct pinion and ring gear configurations, allowing for parallel alignment of pinions and optimized gear ratios, which reduces NVH and enhances operational efficiency by positioning components to minimize frictional drag and improve gear operating efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If traditional tandem axle configurations are used, then structural simplicity is maintained, but noise, vibration, and harshness (NVH) increase along with frictional drag
Solution Approach 1:
The drive axle system is divided into two distinct drive axle assemblies (first and second assemblies), each with separate pinion and ring gear configurations. This segmentation allows each assembly to be optimized independently for NVH reduction while maintaining overall system functionality.
Solution Approach 2:
Each drive axle assembly features locally optimized gear configurations with specific tooth counts and geometric parameters tailored to minimize NVH. The first pinion has a first number of teeth and the second pinion has a second number of teeth, creating local variations that reduce vibration and noise throughout the system.
2Productivity
If conventional gear configurations are used, then manufacturing simplicity is maintained, but gear operating efficiency decreases due to frictional drag
Solution Approach 1:
The patent applies specific parameter changes to the gear configurations, including optimized tooth counts, pressure angles, and helix angles for both pinions and ring gears. These parameter optimizations reduce frictional drag and improve gear operating efficiency while remaining manufacturable using conventional processes.
Solution Approach 2:
The gear designs incorporate dynamic considerations in their configuration, with tooth profiles and spacing optimized to minimize impact loads and friction during operation. This dynamic optimization improves efficiency without significantly complicating manufacturing.
3Object-affected harmful factors
If parallel pinion alignment is implemented, then NVH reduction is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent employs asymmetric gear configurations where the first pinion and second pinion have different numbers of teeth and different geometric parameters. This asymmetry in design allows the parallel alignment to be achieved more easily while still providing NVH reduction benefits.
Solution Approach 2:
The parallel alignment of the first pinion axis and second pinion axis creates an equipotential configuration that balances the NVH characteristics of both drive axle assemblies. This balanced arrangement reduces vibration while maintaining reasonable manufacturing tolerances.
4Speed
If optimized gear ratios are used, then speed performance improves, but component stress increases
Solution Approach 1:
The patent optimizes the gear ratios by carefully selecting the number of teeth on each pinion and ring gear combination. The first pinion with its first number of teeth meshing with the first ring gear, and the second pinion with its second number of teeth meshing with the second ring gear, creates optimized speed ratios that balance performance with stress reduction.
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
The system achieves reduced noise, vibration, and harshness, along with improved gear operating efficiency and faster gear ratios, while maintaining structural integrity and reducing stress on components, thus enhancing overall vehicle performance.
Implementation Method 1
The first pinion rotates about a first pinion axis and provides torque to the first ring gear. The driven gear may be disposed on the first pinion and may engage the drive gear. The second pinion rotates about a second pinion axis and is operatively connected to the output shaft. The second pinion provide torques from the output shaft to the second ring gear.
Data Source
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AI summary
A drive axle system 24 that may have a first drive axle assembly 30 and a second drive axle assembly 32. The first drive axle assembly may have a first pinion 74 that may rotate about a first pinion axis 90. The second drive axle assembly may have a second pinion 134 that may rotate about a second pinion axis 140. The first pinion axis 90 may be disposed substantially parallel to the second pinion axis 140.