4WD Transfer Layout for Wide Torque Split Control
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Solution Overview
Problem
Existing four-wheel drive vehicle transfer systems struggle to control a wide range of power distribution ratios both on straight travel and during cornering, and often require a complex configuration that is not compact enough.
Innovation Solution
The system incorporates a first and second distribution mechanism, each with a clutch and a planetary gear set, allowing for continuous control of power distribution between the front and rear wheels by adjusting the engagement state of the clutches and gear ratios, enabling a wide range of power distribution from 100:0 to 0:100, and maintaining stability through internal circulation torque management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single distribution mechanism with one clutch is used, then the device complexity is reduced, but the adaptability to control wide range power distribution ratios is insufficient
Solution Approach 1:
The transfer mechanism is divided into a first distribution mechanism and a second distribution mechanism, each capable of independently controlling power distribution to front and rear wheels. This segmentation allows each mechanism to handle specific power distribution tasks, enabling a wider overall control range while keeping individual mechanism complexity manageable
Solution Approach 2:
Both distribution mechanisms share common components such as the input shaft and clutch assembly, allowing them to perform multiple functions. The first clutch can control both distribution mechanisms simultaneously, and the planetary gear sets serve dual purposes in power distribution and torque management, reducing overall system complexity while maintaining adaptability
2Adaptability or versatility
If multiple clutches and planetary gear sets are added to expand power distribution control, then the adaptability improves, but the device complexity increases
Solution Approach 1:
The first and second distribution mechanisms are merged into a unified structure where they share the input shaft, clutch housing, and planetary gear carrier. This combining approach allows two distribution functions to coexist while minimizing the number of separate components, thus improving adaptability without proportionally increasing complexity
Solution Approach 2:
The planetary gear sets are nested within the clutch assembly structure, with the sun gear, planet gears, and ring gear arranged in a compact configuration. The first and second distribution mechanisms are nested side-by-side, sharing common structural elements, which reduces overall device complexity while maintaining the capability for wide range power distribution control
Data Source
AI summary
A transfer for a four wheel drive vehicle includes first and second distribution mechanisms. The first distribution mechanism includes a first clutch and is configured to distribute a portion of power from a power source to a second transmission mechanism through the first clutch. The second distribution mechanism includes a planetary gear set and a second clutch, and is configured to distribute a portion of power from the power source to a second transmission mechanism through the planetary gear set and the second clutch in order. The first and second clutches are configured to be controlled to a half-engaged state between engagement and disengagement. An input shaft of the first distribution mechanism and an input shaft of the planetary gear set are unitized.