Brake Simulator Elastic Portion Segmentation for Smooth Reaction Force
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Solution Overview
Problem
The existing vehicular brake systems with by-wire technology experience a feeling of strangeness due to a singularity of dogleg shape at the switching point where the reaction force linear characteristics switch between different elastic moduli, affecting the brake operation experience.
Innovation Solution
A vehicular hydraulic-pressure generation device with a reaction force generation section that includes a simulator piston and elastic portions with varying elastic moduli, specifically a first, second, and third elastic portion, to smooth the transition of reaction force characteristics, reducing the strangeness felt during brake operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If two elastic members with different elastic moduli are disposed serially to create reaction force characteristics, then appropriate reaction force corresponding to brake operation amount is achieved, but a singularity of dogleg shape is generated at the switching point causing a feeling of strangeness
Solution Approach 1:
The elastic portion is segmented into three distinct elastic members (first, second, and third elastic portions) with different elastic moduli arranged in series. This segmentation allows the reaction force characteristic to be divided into multiple stages, with each stage providing a different level of stiffness. The three-stage segmentation smooths the transition between stiffness levels, preventing the sharp singularity that would occur with only two stages, while still achieving the desired progressive reaction force characteristic.
Solution Approach 2:
The invention changes the parameter of elastic modulus by using three different elastic moduli (first elastic modulus, second elastic modulus larger than the first, and third elastic modulus smaller than the second) instead of just two. This parameter variation creates a more gradual transition in the reaction force characteristic, reducing the sharpness of the switching point singularity and improving the overall smoothness of the brake operation feeling.
2Force
If elastic members with different elastic moduli are used to match reaction force to operation amount, then small reaction for small operation and large reaction for large operation is achieved, but the transition between different elastic modulus characteristics creates a noticeable singularity
Solution Approach 1:
The elastic portion is segmented into three distinct elastic members (first, second, and third elastic portions) with different elastic moduli arranged in series. This segmentation allows the reaction force characteristic to be divided into multiple stages, with each stage providing a different level of stiffness. The three-stage segmentation smooths the transition between stiffness levels, preventing the sharp singularity that would occur with only two stages, while still achieving the desired progressive reaction force characteristic.
Solution Approach 2:
The invention changes the parameter of elastic modulus by using three different elastic moduli (first elastic modulus, second elastic modulus larger than the first, and third elastic modulus smaller than the second) instead of just two. This parameter variation creates a more gradual transition in the reaction force characteristic, reducing the sharpness of the switching point singularity and improving the overall smoothness of the brake operation feeling.
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 the feeling of strangeness by smoothing the reaction force characteristic transition at the switching point, providing a more conventional brake-like experience in by-wire systems.
Implementation Method 1
an elastic portion provided on a side of the forward direction of the simulator piston, and wherein the elastic portion is formed by a first elastic portion having a first elastic modulus, a second elastic portion having a second elastic modulus larger than the first elastic modulus, and a third elastic portion having a third elastic modulus smaller than the second elastic modulus
Data Source
AI summary
A vehicular hydraulic-pressure-generation device wherein a first bush compressively deforms due to pressure from a simulator piston that moves when hydraulic pressure produced when a brake pedal is depressed is transmitted into a cylinder part. Said vehicular hydraulic-pressure-generation device thus creates artificial reaction-force characteristics with respect to the position of the brake pedal. The aforementioned first bush has a third elastic modulus, which is smaller than a second elastic modulus, and is provided in parallel with a first return spring. The compressive deformation of the first bush occurs over a second region that overlaps a first region in which compressive deformation of the return spring primarily occurs. This makes the brake pedal move more smoothly, reducing the feeling of incongruity resulting from a V-shaped singularity in the reaction-force characteristics with respect to brake pedal position.