Vehicle Driving Force Distribution Device Drag Torque Reduction
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Solution Overview
Problem
Existing vehicle driving force distribution devices experience drag torque issues in two-wheel drive mode, leading to power loss and reduced fuel economy due to lubricating oil viscosity between clutch plates.
Innovation Solution
A vehicle driving force distribution device with a differential gear and a driving force transmission system that includes flow passages to manage lubricating oil flow between accommodating chambers, reducing drag torque by adjusting oil distribution based on shaft rotation directions, thereby minimizing frictional resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lubricating oil is present between clutch plates to reduce abrasion and achieve smooth frictional sliding, then reliability is improved, but drag torque increases in two-wheel drive mode causing power loss
Solution Approach 1:
The accommodating chamber is divided into a first accommodating chamber for the differential gear and a second accommodating chamber for the driving force transmission device, with separate flow passages controlling lubricating oil distribution to each chamber based on operational mode
Solution Approach 2:
The system dynamically adjusts lubricating oil distribution based on rotation direction detection. When the intermediate shaft and second output shaft rotate in opposite directions (two-wheel drive mode), lubricating oil is directed away from the clutch plates to minimize drag torque. When rotating in the same direction (four-wheel drive mode), lubricating oil is supplied to ensure smooth operation and reduce abrasion
2Reliability
If the propeller shaft and differential case rotate in two-wheel drive mode to maintain gear lubrication, then reliability is improved, but fuel economy deteriorates due to unnecessary rotation and stirring resistance
Solution Approach 1:
Different parts of the system are treated differently based on operational requirements. The differential gear receives continuous lubrication regardless of mode, while the clutch system selectively receives lubricating oil only when needed (in four-wheel drive mode), optimizing both reliability and fuel economy
Solution Approach 2:
The system uses the rotation direction itself as the control signal to automatically switch lubricating oil flow paths, eliminating the need for external sensors or control systems. The flow passages are designed to automatically direct lubricating oil based on the rotational state of the shafts
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 solution effectively reduces drag torque in two-wheel drive mode, enhancing fuel economy by optimizing lubricating oil distribution and minimizing frictional losses within the clutch system.
Implementation Method 1
Lubricating oil is present between the outer and inner clutch plates in order to reduce abrasion and achieve smooth frictional sliding
Implementation Method 2
drag torque is generated between the plurality of outer clutch plates and the plurality of inner clutch plates of the multi-plate clutch by viscosity of the lubricating oil
Implementation Method 3
The multi-plate clutch is formed by alternately arranging a plurality of outer clutch plates and a plurality of inner clutch plates in the axial direction... When the multi-plate clutch is pressed by the pressing mechanism, the clutch housing is coupled to the inner shaft, and a driving force is transmitted to the right and left rear wheels
Data Source
AI summary
A vehicle driving force distribution device includes: a differential gear; a driving force transmission device; and a case member having a first accommodating chamber accommodating the differential gear and a second accommodating chamber accommodating the driving force transmission device. The case member has a first flow passage that allows lubricating oil to flow from the first accommodating chamber into the second accommodating chamber, and a second flow passage that allows lubricating oil to flow from the second accommodating chamber into the first accommodating chamber. In a two-wheel drive mode, lubricating oil flows from the second accommodating chamber into the first accommodating chamber through the second flow passage. In a four-wheel drive mode, lubricating oil flows from the first accommodating chamber into the second accommodating chamber through the first flow passage.