Electric Drive Axle Gear Train With Nested Intermediate Gears
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Solution Overview
Problem
Previous electric drive axle gear trains face challenges in achieving precise gear grinding and compact packaging due to manufacturing techniques, leading to conflicts between gear precision and space efficiency.
Innovation Solution
The gear train design includes an intermediate shaft with gears of different sizes, where a larger gear is coupled to a sleeve of a smaller gear, allowing for high accuracy and compact arrangement, and a method of manufacturing involving forming a first gear on the outer surface of the intermediate shaft, press-fitting a second gear, and installing a third gear onto an axial section, enabling high-speed operation with reduced noise, vibration, and harshness (NVH).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional manufacturing techniques are used for gear grinding, then gear precision can be achieved, but the packaging space increases and compact arrangement becomes difficult
Solution Approach 1:
The patent applies nesting by placing the axial extension of the third gear inside the interior space of the second gear. The axial extension protrudes axially from the third gear and is surrounded by the interior surface of the second gear, creating a nested configuration that reduces overall packaging space while maintaining gear precision through conventional manufacturing techniques
Solution Approach 2:
The patent utilizes the axial dimension by extending the third gear axially to create an axial extension that fits within the radial space of the second gear. This dimensional arrangement allows gears to be packed more efficiently in the radial direction while maintaining precision manufacturing capabilities
2Volume of moving object
If gears are arranged in a compact configuration, then space efficiency increases, but manufacturing precision and gear grinding accuracy become more difficult to achieve
Solution Approach 1:
The nested configuration allows the axial extension of the third gear to be positioned within the interior space of the second gear, achieving compact packaging without compromising the ability to manufacture each gear with high precision using conventional grinding techniques
3Object-affected harmful factors
If gear accuracy is increased to reduce NVH, then noise and vibration decrease, but the complexity of gear arrangement and manufacturing increases
Solution Approach 1:
The nested arrangement of the axial extension within the second gear's interior space achieves a compact configuration that reduces NVH through improved gear meshing accuracy, while the manufacturing process remains relatively simple by using conventional forming and press-fitting techniques
4Ease of manufacture
If conventional gear manufacturing methods are used, then ease of manufacture is maintained, but the ability to achieve high-speed operation with low NVH is compromised
Solution Approach 1:
The nested configuration enables high-speed operation with reduced NVH by improving gear meshing accuracy, while maintaining ease of manufacture through conventional processes including forming gears on shafts, press-fitting gears onto shafts, and assembling gear trains using standard manufacturing techniques
Data Source
AI summary
Methods and systems for an electric drive axle of a vehicle are provided. A gear train in an electric drive axle system includes, in one example, an input shaft configured to rotationally couple to an electric motor-generator and including a first gear and an intermediate shaft including a second gear rotationally coupled to the first gear and a third gear and a fourth gear each configured to rotationally couple to a separate gear on an output shaft. In this example, the second gear, the third gear, and the fourth gear have different sizes, the third gear includes an axial extension having at outer surface, and an interior surface of the second gear circumferentially surrounds at least a portion of the outer surface of the axial extension.