Rear Brake Force Distribution for Smooth Vehicle Stops
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Solution Overview
Problem
Existing brake systems fail to effectively reduce vehicle posture changes during braking, leading to uncomfortable feelings, especially when vehicles are slowly stopped, and may disturb vehicle behavior by reducing total braking force.
Innovation Solution
A brake system with a braking force distribution apparatus that applies more braking force to the rear wheels when the vehicle is slowing down, allowing the front wheels to have minimal braking force, thereby maintaining vehicle stability and reducing posture changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If braking force is applied to all four wheels, then the vehicle stops effectively, but the vehicle posture changes (pitching) causing uncomfortable feeling
Solution Approach 1:
The patent segments the braking function by wheel position, applying different braking strategies to front wheels and rear wheels. The rear wheels (with parking brake mechanisms) maintain braking force to prevent posture change, while front wheels release braking force to allow controlled pitching that reduces uncomfortable feelings.
Solution Approach 2:
Different quality of braking force is applied to different parts of the vehicle. The rear wheels receive sustained braking force to maintain vehicle stability, while the front wheels have reduced braking force to accommodate posture changes. This local differentiation resolves the contradiction between stopping effectiveness and posture stability.
2Stability of the object's composition
If braking force is released from front wheels to reduce posture change, then vehicle comfort improves, but total braking force reduces causing vehicle behavior disturbance
Solution Approach 1:
The parking brake mechanisms on the rear wheels are activated in advance before the front wheel brakes are released. This preliminary action ensures that the rear wheels are already providing sufficient braking force to maintain vehicle stability and prevent posture change, allowing the front brakes to be safely released without causing vehicle behavior disturbance.
Solution Approach 2:
The rear wheel parking brake mechanisms serve as an intermediary to maintain total braking force. When front wheel brakes are released, the rear wheel parking brakes compensate by providing the necessary braking force, thus maintaining overall braking effectiveness while allowing posture changes to be minimized.
3Reliability
If parking brake is actuated after vehicle stop, then vehicle is held stopped, but releasing front wheel braking force causes unconformable feeling
Solution Approach 1:
The braking release process is segmented into two phases: first, the front wheel brakes are released to allow controlled posture adjustment and reduce uncomfortable feelings; second, the rear wheel parking brake mechanisms maintain holding force to ensure the vehicle remains stopped. This segmentation resolves the contradiction between reliability and comfort.
Solution Approach 2:
Instead of releasing all brakes simultaneously after stopping, the patent inverts the sequence by maintaining rear wheel braking force while releasing front wheel braking force. This inverted approach ensures that the vehicle remains reliably stopped through the rear brakes while the front brake release reduces uncomfortable posture changes, improving passenger comfort.
Data Source
AI summary
An ESC 33 increases distribution of a braking force to rear wheels according to a reduction in a speed of a vehicle due to braking, and distributes the braking force so as to allow the vehicle to be kept stopped due to braking forces applied to the rear wheels when the vehicle stopped. Then, a second ECU holds the braking force by driving a parking mechanism with the vehicle kept stopped due to the braking forces applied to the rear wheels.