Gear Unit Parking Lock Layout for Compact EV Drive Packaging
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Solution Overview
Problem
Existing vehicle driving units with integrated electric motors and reduction gear sets face challenges in compact design, leading to issues such as elongated lateral dimensions or elevated center of mass, which affect ride quality and stability.
Innovation Solution
A gear unit with a differential gear set and counter shaft, integrated with a parking lock mechanism, is designed to minimize axial and lateral dimensions by using a hollow output shaft and strategically arranging components within a housing, including a parking gear opposite the first gear and utilizing a compact actuator for the pawl mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If elements are added alongside the electric motor having a laterally directed shaft, then the driving unit can accommodate all components, but the driving unit becomes elongated in the lateral direction requiring shorter axles which have insufficient capacity for rocking and adversely affect ride quality
Solution Approach 1:
The patent repositions the parking lock unit from a lateral arrangement to an axial arrangement along the output shaft. The parking gear is disposed axially opposite to the first gear beyond the second gear, utilizing the axial dimension instead of lateral space. This dimensional shift allows the driving unit to remain compact laterally while accommodating all necessary components.
2Volume of moving object
If the driving unit dimensions are increased in the height direction, then more space is available for components, but the center of mass is set upward and vehicle stability is damaged
Solution Approach 1:
The patent utilizes the axial dimension along the output shaft to accommodate the parking lock unit and other components, rather than increasing the height direction. By arranging the parking gear axially opposite to the first gear and positioning components along the axial direction, the design maintains a low center of mass while providing sufficient internal space for all components.
3Adaptability or versatility
If a parking lock unit is built-in to the reduction gear set, then the driving unit becomes more integrated and compact, but the arrangement of additional elements within the housing becomes more complex
Solution Approach 1:
The patent integrates the parking lock unit with the reduction gear set by disposing the parking gear in mesh relationship with the counter shaft gears. The parking gear is positioned axially opposite to the first gear beyond the second gear, allowing the parking lock mechanism to share the same spatial envelope as the reduction gear set. This merging approach achieves compact integration while managing complexity through systematic component arrangement.
Data Source
AI summary
A gear unit to be used in combination with a power source having a hollow output shaft, is provided with a differential gear set having a rotation axis in common with the output shaft, a counter shaft fixedly including a first gear in mesh with the output shaft, and a second gear in mesh with the differential gear set. The first gear and the second gear constitutes a reduction gear set, a housing including an outer wall parting the differential gear set and the counter shaft from an exterior, and a parking gear disposed axially opposite to the first gear beyond the second gear and fixed to the counter shaft.