Two-Speed Drive Module Radial Dimension Reduction
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Solution Overview
Problem
The existing two-speed drive module in transaxles has a large radial dimension due to the size of the final gear, limiting the output torque and ground clearance, making it unsuitable for vehicles like SUVs.
Innovation Solution
Incorporating a planetary gear set as the final gear in the two-speed drive module, which allows for increased torque amplification and reduced radial dimension, enabling a smaller drive axle case and improved ground clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large diameter final gear is used to increase maximum output torque, then the output torque increases, but the radial dimension of the drive module increases, reducing ground clearance
Solution Approach 1:
The patent applies nesting by placing the two-speed gear set inside the planetary gear set. The two-speed gear set is positioned within the radial space of the planetary gear set, allowing compact arrangement that reduces overall radial dimension while maintaining torque amplification capability through the combined gear systems
Solution Approach 2:
The patent transitions from a single radial gear arrangement to a multi-dimensional layout by introducing axial positioning of the two-speed gear set within the planetary gear set. This spatial reorganization in multiple dimensions (radial and axial) enables compact packaging that reduces the drive module's radial footprint while preserving torque output
2Force
If a large diameter final gear is used to increase maximum output torque, then the output torque increases, but the drive axle case diameter increases, reducing ground clearance
Solution Approach 1:
The two-speed gear set is nested within the planetary gear set structure, allowing both gear systems to share the same radial envelope. This nested arrangement enables the drive axle case to have a smaller diameter since the gear sets are concentric rather than radially stacked, thereby improving ground clearance while maintaining torque amplification
3Length of stationary object
If the radial dimension of the drive module is reduced, then ground clearance improves, but the maximum output torque is limited
Solution Approach 1:
The patent merges the two-speed gear set and planetary gear set into a integrated drive module where both systems work together. The two-speed gear set provides initial torque multiplication, and the planetary gear set provides additional torque amplification, achieving high output torque in a compact radial footprint through combined gear ratios
Solution Approach 2:
The planetary gear set serves multiple functions: it acts as the final reduction stage, provides additional torque amplification, and accommodates the two-speed gear set within its structure. This multi-functionality allows the system to achieve high torque output without increasing radial dimension, as the planetary gear set simultaneously serves as both a functional element and a structural container
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 planetary gear set enhances torque amplification while reducing the radial size of the drive module, increasing ground clearance and allowing for more space, particularly beneficial for vehicles like SUVs.
Implementation Method 1
a planetary gear set, the shift gear pairs is capable of being connected or disconnected from the input shaft drive, to output the rotational speed of the input shaft at different ratios to the planetary gear set
Data Source
AI summary
A transaxle and a two-speed drive module thereof. The two-speed drive module comprises an input shaft, an output shaft, and gear sets used for transmitting power between the input shaft and the output shaft. The gear sets comprise: a two-speed gear set having two groups of shift gear pairs that have different speed ratios, the shift gear pairs being capable of transmittingly connecting to or disconnecting from the input shaft so as to output the rotational speed of the input shaft at different speed ratios; a planetary gear set having an output end thereof being transmittingly connected to the output shaft; and a connecting gear set by which the two-speed gear set is transmittingly connected to the planetary gear set. The two-speed drive module can implement a reduction in the radial dimension, and can reduce the ground clearance of a transaxle.