Brake Pedal Stroke Simulator With Recessed Elastic Member

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Solution Overview

Problem

Existing stroke simulators for brake systems face challenges in providing a moderate operation feel while ensuring a sufficient stroke, as reducing clearance between the control piston and elastic member to increase simulative reaction force leads to rapid compression suppression, limiting the brake pedal's stroke.

Innovation Solution

A stroke simulator design featuring a piston and elastic member with outer circumferential recesses on the elastic member, allowing gradual compression and increased spring constant, enabling further piston movement and maintaining a moderate operation feel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the clearance between the control piston and elastic member is reduced to increase simulative reaction force, then the operation feel on the brake pedal becomes harder, but the stroke of the brake pedal is reduced

Engineering Contradiction:
Improvesimulative reaction forceVSAvoidstroke of brake pedal
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The elastic member is designed with an annular recess at its center portion, creating local structural differentiation. This allows the central region to be more compliant while the outer regions maintain contact with the control piston, enabling the system to provide both hard operation feel and sufficient stroke

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The elastic member's cross-section is effectively segmented into a central recessed portion and outer contact portions. This segmentation allows different regions to perform different functions: the outer portions contact the piston for force transmission, while the central recessed portion deforms to accommodate piston movement

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If the clearance between the control piston and elastic member is reduced to obtain a hard operation feel, then the elastic member comes into contact with the control piston in an early stage, but the compression is rapidly suppressed leading to reduced stroke

Engineering Contradiction:
Improveoperation feelVSAvoidstroke
Core Design Contradiction:
Ease of operationVSLength of moving object

Solution Approach 1:

The annular recess at the center of the elastic member creates local quality differentiation, making the central region more compliant while maintaining outer region contact. This allows the elastic member to gradually increase spring constant through controlled deformation rather than rapid suppression

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The elastic member transitions from a static uniform structure to a dynamic structure where the effective contact area changes during compression. As the piston moves, the elastic member deforms radially outward, dynamically adjusting the contact interface between the piston and elastic member

Inventive Principle:
Principle #15Dynamics

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 design enhances the brake operation's stroke and stability by allowing the elastic member to deform radially outward, ensuring a moderate operation feel and sufficient pedal stroke, while also facilitating easy piston return.

Implementation Method 1

the inner surface of the outer circumferential recess is allowed to be deformed in the radially outward direction of the elastic member, so that the elastic member can continue to be compressed

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

by operating the brake operation member to generate a fluid pressure in a master cylinder and transmit this fluid pressure to the cylinder body, thereby deforming the elastic member through the piston

Methodology Applied
Scientific EffectHydraulic pressure transmission: Pascal's Law

Data Source

PatentEP2168824B1Brake pedal stroke simulator
Publication Date: 2013.05.01 HONDA MOTOR CO LTD
  • EP2168824B1 patent drawingFigure 1
  • EP2168824B1 patent drawingFigure 2(a)~2(b)
  • EP2168824B1 patent drawingFigure 3~4

AI summary

Object To provide a stroke simulator in a brake system which can make the operation feel on a brake operation member moderately hard and can also ensure the stroke of the brake operation member. Solving Means Disclosed herein is a stroke simulator (28) in a brake system including a cylinder body (101), a piston (102) movably inserted in the cylinder body (101), and a second elastic member (154) adapted to be pressed by the piston (102), and functioning to give a simulative operation feel to a brake lever by operating the brake lever to generate a fluid pressure in a front wheel master cylinder and transmit this fluid pressure to the cylinder body (101), thereby deforming the second elastic member (154) through the piston (102), wherein recesses (154d) are formed on the outer circumferential surface (154g) of the second elastic member (154). With this arrangement, the elastic member (154) is pressed by the piston (102) to increase in diameter in the cylindrical body (101), so that the outer circumferential surface (154g) of the elastic member (154) comes into contact with the inner circumferential surface (101a) of the cylindrical body (101) to thereby gradually increase the spring constant of the elastic member (154).