Rear Wheel Driving Device Power Loss Reduction
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Solution Overview
Problem
Conventional 4-wheel drive electric vehicles experience power loss due to slip in clutches and load-generated losses from differential gears during 4-wheel and 2-wheel driving modes.
Innovation Solution
A driving device for rear wheels that uses a disconnector input shaft instead of a clutch to synchronize the rotating speed with the hub, minimizing power loss by connecting the differential device between the reduction gear group and the disconnector input shaft to prevent load generation during 2-wheel driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a clutch is used to transfer drive power to rear wheels, then 4-wheel driving capability is achieved, but drive power loss occurs due to clutch slip
Solution Approach 1:
The patent extracts and removes the clutch component from the power transmission system. Instead of using a clutch to engage/disengage power to rear wheels, the invention uses a disconnector input shaft that can be directly connected or disconnected from the hub, eliminating the slip loss inherent in clutch mechanisms while maintaining 4-wheel driving capability.
Solution Approach 2:
The patent replaces the mechanical clutch system with a different mechanical approach using a disconnector input shaft and hub connection mechanism. This substitution eliminates the friction-based slip of clutches while achieving the same functional goal of selective power transmission to rear wheels.
2Adaptability or versatility
If a differential device is connected between reduction gear group and disconnector input shaft, then 4-wheel drive power distribution is enabled, but load-generated loss occurs during 2-wheel driving
Solution Approach 1:
The patent implements a dynamic connection system where the differential device can be selectively connected or disconnected based on driving mode. During 2-wheel driving, the differential device is disconnected to prevent load-generated losses, while during 4-wheel driving, it is connected to enable proper power distribution. This dynamic configuration allows the system to adapt its structure to operational requirements.
3Loss of energy
If clutch is replaced with disconnector input shaft, then drive power loss is minimized, but speed synchronization control complexity increases
Solution Approach 1:
The patent incorporates a feedback control system using a wheel speed sensor to detect the rotating speed of the hub, and a controller that compares this speed with the motor's rotating speed. Based on this feedback, the controller adjusts the motor's output to synchronize speeds before connecting the disconnector input shaft to the hub, ensuring smooth engagement while maintaining speed synchronization.
Data Source
AI summary
Provided is a driving device for rear wheels of a 4 wheel driving electric vehicle, which can minimize a loss in the drive power during 4-wheel by transmitting the drive power to the rear wheels based on a disconnector input shaft, rather than a clutch, after synchronizing a rotating speed of the disconnector input shaft based on a first motor with a rotating speed of a hub based on rear wheels. Other aspects of the present invention provide a driving device for rear wheels of a 4 wheel driving electric vehicle, which can prevent a loss in the drive power during 2-wheel driving by preventing a load based on a differential device from being generated by connecting the differential device between a reduction gear group and the disconnector input shaft.