Stroke Simulator Cup Seal Axial Centering

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Solution Overview

Problem

The piston in existing stroke simulators can become inclined due to a small gap between the piston and the sliding surface, leading to increased sliding friction and a change in the operation feeling of the brake pedal.

Innovation Solution

A stroke simulator design that includes a cup seal attached to the axial center of the sliding surface, preventing the piston from inclining by maintaining contact at the axial center, thus reducing sliding friction and maintaining consistent operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a small gap is formed between the piston and the sliding surface, then the piston can move smoothly, but the piston becomes inclined and sliding friction increases

Engineering Contradiction:
Improvepiston movement smoothnessVSAvoidsliding friction
Core Design Contradiction:
SpeedVSForce

Solution Approach 1:

A cup seal is introduced as an intermediary component between the piston and the sliding surface. The cup seal is attached to the sliding surface and contacts the piston at its axial center, preventing piston inclination while maintaining smooth movement. This mediator resolves the contradiction by eliminating the harmful inclination effect while preserving the beneficial smooth movement capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the piston is inclined with respect to the sliding surface, then the gap allows movement, but the operation feeling of the brake pedal changes

Engineering Contradiction:
Improvebrake pedal operation feelingVSAvoidpiston alignment stability
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The cup seal serves as a mediator that contacts the piston at its axial center, preventing inclination and maintaining stable piston alignment. This ensures consistent brake pedal operation feeling while allowing necessary piston movement through the sealed gap.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the cup seal is attached at the axial center of the sliding surface, then piston inclination is suppressed, but the seal structure becomes more complex

Engineering Contradiction:
Improvepiston alignment stabilityVSAvoidseal structure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The cup seal is positioned specifically at the axial center of the sliding surface, applying the sealing function locally where it is most needed to prevent piston inclination. This localized approach maintains overall system simplicity while achieving the desired stability improvement.

Inventive Principle:
Principle #3Local quality

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 suppresses piston inclination, ensuring consistent brake pedal operation and maintaining the intended operation feeling by ensuring the cup seal is in contact with the piston at the axial center, thereby reducing sliding friction.

Implementation Method 1

the inner peripheral portion is deformed in response to the hydraulic pressure in the first cylinder and the second cylinder

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

a hydraulic pressure which is generated by a hydraulic pressure generating unit due to an operation of a brake operating element

Methodology Applied
Scientific EffectHydraulic pressure: Pascal's Law

Implementation Method 3

a reaction force generating unit which applies a reaction force corresponding to a displacement of the simulator piston to the simulator piston

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP2835294B1Stroke simulator
Publication Date: 2018.05.09 HONDA MOTOR CO LTD
  • EP2835294B1 patent drawingFigure 1
  • EP2835294B1 patent drawingFigure 2A~2B
  • EP2835294B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a stroke simulator capable of suppressing occurrence of inclination of a piston with respect to a sliding surface formed in a cylinder. The stroke simulator includes a simulator piston (2a) which is displaced by sliding on a sliding surface (205) formed in a first cylinder (201), in response to a hydraulic pressure which is generated in a master cylinder due to an operation of a brake pedal by a driver, and a first return spring which is housed in the first cylinder (201) and applies, to the simulator piston (2a), a reaction force which is generated by an elastic deformation of the spring under a pressing force due to a displacement of the simulator piston (2a), and generates the reaction force which is applied to the simulator piston (2a) as a brake reaction force for a brake operating element. The stroke simulator is characterized in that a cup seal (201b) for sealing a gap formed between the sliding surface (205) and the simulator piston (2a) is mounted in the center (CL) in the axial direction of the sliding surface (205).