Stroke Simulator Plug Geometry for Brake Pedal Feel
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Solution Overview
Problem
The existing stroke simulators experience an impact issue when the piston bottoms out, impairing the driver's feeling during braking due to a sudden increase in the rate of change of reactive force, particularly when the relationship between piston movement and force is linear.
Innovation Solution
A stroke simulator design that incorporates a piston, reactive rubber, and a plug within a cylinder, where the plug increases sliding resistance as the rubber is compressed, enhancing the friction force and thus the reactive force as the piston approaches the bottoming position, thereby reducing impact and improving the operational feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a linear relationship between piston movement distance and reactive force is used, then the brake pedal operation follows a predictable gradient, but an impact occurs when the piston bottoms out due to sudden increase in rate of change of reactive force
Solution Approach 1:
The plug's inner circumferential surface is designed with a variable radius of curvature, creating a dynamic change in sliding resistance as the piston moves. This dynamic geometry allows the sliding resistance to increase progressively as the reactive rubber compresses, softening the bottoming impact while maintaining predictable operation throughout the stroke range
Solution Approach 2:
The invention changes the geometric parameter of the plug's inner circumferential surface (radius of curvature) to modify the sliding resistance characteristic. By making the radius of curvature variable rather than constant, the system transforms the reactive force profile to reduce the rate of change at bottoming, thereby reducing impact while maintaining operational predictability
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 increased friction force between the reactive rubber and the plug results in a greater increase in reactive force relative to piston movement closer to the bottoming position, reducing impact and enhancing the operational feeling during braking.
Implementation Method 1
a reactive rubber that is disposed inside the cylinder and that applies a reactive force to the piston by being compressed by a movement of the piston to one side
Implementation Method 2
a plug that is disposed inside the cylinder so as to surround an outer circumferential surface of the reactive rubber and that increases a sliding resistance against a movement of the reactive rubber to the one side as the reactive rubber is compressed
Data Source
AI summary
The present disclosure includes: a cylinder; a piston that moves inside the cylinder in response to the operation of a brake pedal; a reactive rubber that is disposed inside the cylinder and that applies a reactive force to the piston by being compressed by the movement of the piston to one side; and a plug that is disposed inside the cylinder so as to surround an outer circumferential surface of the reactive rubber and that increases a sliding resistance against the movement of the reactive rubber to one side as the reactive rubber is compressed.