Dual-Bore Master Cylinder Structure for Leak and Vibration Control

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Solution Overview

Problem

Existing master cylinders face challenges in ensuring operational reliability, reducing noise and vibration, maintaining a constant working stroke of the piston, preventing medium leakage and foreign substance inflow, and improving durability while promoting assembly and miniaturization.

Innovation Solution

The master cylinder design incorporates a hydraulic block with main and sub bores, pistons, elastic members, sealing members, bush members, and a boot with a vent hole to guide piston movement, reduce friction, and prevent leakage, along with a noise suppression protrusion to alleviate vibration and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional master cylinder design is used, then the structure is simple, but operational reliability is insufficient and noise/vibration cannot be reduced

Engineering Contradiction:

Improveoperational reliabilityVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The master cylinder is divided into separate functional blocks: a hydraulic block containing the main bore and hydraulic flow paths, and a mounting block containing the sub bore and connection flow paths. This segmentation allows each block to be optimized independently for its specific function while improving overall reliability through modular design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first piston is inserted through the sub bore of the mounting block, and the second piston is inserted into the main bore of the hydraulic block. The elastic member is nested between the two pistons. This nested arrangement allows compact integration of multiple functional elements within the dual-block structure.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Force

If the piston is displaced for braking operation, then braking force is generated, but noise and vibration are produced

Engineering Contradiction:

Improvebraking forceVSAvoidnoise and vibration

Core Design Contradiction:

ForceVSObject-generated harmful factors

Solution Approach 1:

Bush members are introduced as intermediary elements between the first piston and the sub bore, and between the second piston and the main bore. These bush members reduce direct metal-to-metal contact and friction during piston displacement, thereby reducing noise and vibration while maintaining braking force generation.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The elastic member, which inherently generates some vibration during compression and expansion, is positioned to work in conjunction with the bush members. The combination converts the potentially harmful elastic vibrations into beneficial damping effects that reduce overall noise and vibration during piston operation.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If sealing components are added to prevent leakage, then medium leakage is prevented, but assembly complexity increases

Engineering Contradiction:

Improveleakage preventionVSAvoidassembly ease

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple sealing functions are merged into integrated sealing members that combine several sealing features in a single component. These sealing members are designed to seal multiple interfaces simultaneously, reducing the total number of separate sealing components needed and simplifying assembly.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The sealing members are designed with multi-functional capabilities, serving as both seals and structural support elements. This universality reduces the number of separate components needed and simplifies the assembly process while maintaining effective leakage prevention.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This design enhances operational reliability, reduces noise and vibration, maintains a consistent piston stroke, prevents medium leakage and foreign substance ingress, and improves product durability and assembly efficiency.

Implementation Method 1

an elastic member provided between the first piston and the second piston and configured to provide a pedal feel

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Implementation Method 2

bush members provided in the sub bore and the main bore, respectively, and configured to reduce friction

Methodology Applied

Scientific EffectFriction reduction: Lubrication

Data Source

PatentUS12194967B2Master cylinder

Publication Date: 2025.01.14 HL MANDO CORP

AI summary

Disclosed is a master cylinder. The master cylinder includes a hydraulic block provided with a main bore formed therein in an axial direction, a first piston having one side inserted into the main bore to be displaceable and the other side exposed to an outside of the hydraulic block and connected to a brake pedal, a second piston inserted into the main bore more inside than the first piston to be displaceable, an elastic member provided between the first piston and the second piston and configured to provide a pedal feel, and a mounting block provided with a sub bore formed therein in the axial direction and the sub bore where the first piston is inserted thereinto and passes therethrough to be displaceable and having one side coupled to the other side of the hydraulic block, wherein the hydraulic block includes at least one hydraulic flow path formed through the other side, and the mounting block includes a connection flow path allowing the sub bore to communicate with the hydraulic flow path.