Brake Apparatus with Valve Unit for Rear-Wheel Drive Stability
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Solution Overview
Problem
In rear-wheel-drive electric vehicles, regenerative braking cooperative control can lead to increased wheel lock probability and deteriorated vehicle attitude stability due to uneven braking force distribution between front and rear wheels.
Innovation Solution
A brake apparatus with a regenerative brake unit, master cylinder, and valve unit that differentially applies frictional braking force to front and rear wheels, restricting rear wheel braking force through a valve system to maintain preset braking distribution conditions, ensuring greater braking force is applied to the front wheels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If regenerative braking cooperative control is applied to rear-wheel-drive vehicles, then fuel efficiency is improved through energy recovery, but the probability of rear wheel lock increases and vehicle attitude stability deteriorates
Solution Approach 1:
The patent applies different braking force distribution strategies to different wheels based on their specific roles. The rear wheels receive restricted braking force through the valve unit to prevent lock, while front wheels receive full braking force. This local differentiation in braking characteristics resolves the contradiction by allowing regenerative braking energy recovery while maintaining overall vehicle stability through asymmetric braking force management.
Solution Approach 2:
The valve unit acts as an intermediary device between the master cylinder and rear wheel brake system. It mediates the braking force transmission by selectively restricting hydraulic pressure to rear wheels, thereby preventing rear wheel lock while allowing regenerative braking to operate. This intermediary mechanism enables the system to achieve both energy recovery and stability requirements simultaneously.
2Stability of the object's composition
If braking force is increased on rear wheels to match front wheel braking force, then braking balance is improved, but rear wheel lock probability increases and vehicle stability deteriorates
Solution Approach 1:
The patent deliberately creates asymmetric braking force distribution between front and rear wheels through the valve unit. Instead of applying equal braking force to maintain apparent balance, the system applies restricted braking force to rear wheels and full braking force to front wheels. This asymmetric approach actually achieves better overall vehicle stability by preventing rear wheel lock while maintaining adequate total braking capability.
3Reliability
If frictional braking force is differentially applied to front and rear wheels with restriction on rear wheels, then vehicle attitude stability is maintained, but braking system complexity increases
Solution Approach 1:
The braking system is segmented into two independent control paths: one for front wheels and one for rear wheels. The valve unit creates a separate hydraulic control circuit for rear wheels that can be independently regulated. This segmentation allows differential braking force application while maintaining a relatively simple overall system structure that can be integrated into existing braking architectures.
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
This configuration secures vehicle attitude stability by limiting rear wheel braking force, reducing the likelihood of wheel lock and maintaining stable vehicle control without requiring expensive additional devices, while also reducing production costs.
Implementation Method 1
Energy resulting from counter electromotive force generated by the electric motor is stored in a battery
Implementation Method 2
the electric booster braking system boosts the braking hydraulic pressure with the force of an electric booster (i.e., a motor) using electric energy
Implementation Method 3
a valve unit configured to adjust the master braking hydraulic pressure formed by the master cylinder so that the frictional braking force is differentially applied to the front wheels and the rear wheels
Implementation Method 4
frictional braking force determined by subtracting regenerative braking force generated by the regenerative brake unit from braking force demanded by a driver
Data Source
AI summary
A brake apparatus for vehicles may include: a regenerative brake unit configured to perform a regenerative braking operation of a rear-wheel-drive vehicle; a master cylinder configured to form master braking hydraulic pressure using an operation of an actuator to apply, to front wheels and rear wheels of the rear-wheel-drive vehicle, frictional braking force determined by subtracting regenerative braking force generated by the regenerative brake unit from braking force demanded by a driver; and a valve unit configured to adjust the master braking hydraulic pressure formed by the master cylinder so that the frictional braking force is differentially applied to the front wheels and the rear wheels, and to restrict braking force for the rear wheels from being increased by regenerative braking force applied to the rear wheels.