Plastic Master Cylinder Piston with Embedded Magnet

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Solution Overview

Problem

The manufacturing of primary pistons for tandem master cylinders is costly and complex, particularly in detecting braking requests through the kinematic chain, as existing solutions rely on expensive materials like aluminum and intricate mechanisms.

Innovation Solution

A primary piston made of plastic material with integrated magnets and fiber reinforcement, incorporating a magnetic crown for movement detection, which simplifies production and enhances rigidity without increasing size or complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a primary piston is made of light metal alloy or aluminum, then the structural strength and rigidity are sufficient, but the manufacturing cost is high and the production process is complex

Engineering Contradiction:

Improvemanufacturing cost and production complexityVSAvoidstructural strength and rigidity

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent uses a composite structure consisting of a plastic piston body reinforced with a metallic skeleton (made of light metal alloy or aluminum). This composite approach combines the cost advantages and ease of molding of plastic with the structural strength and rigidity of metal, resolving the contradiction between manufacturing ease and structural strength

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The metallic skeleton is strategically positioned only in critical areas where strength and rigidity are needed, rather than using metal for the entire piston. This localized reinforcement reduces material costs and manufacturing complexity while maintaining sufficient structural performance

Inventive Principle:

Principle #3Local quality

2Difficulty of detecting and measuring

If movement detection means are integrated into the primary piston, then braking request detection is simplified, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improvebraking request detectionVSAvoidpiston structure complexity

Core Design Contradiction:

Difficulty of detecting and measuringVSDevice complexity

Solution Approach 1:

The detection means (magnet) is merged directly into the piston body during the molding process. The magnet is embedded in the plastic material, eliminating the need for separate detection components and reducing overall device complexity while maintaining effective braking request detection

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces complex mechanical detection mechanisms with a magnetic detection system. The magnet embedded in the piston interacts with external magnetic sensors to detect braking requests, substituting mechanical linkages with a simpler magnetic field-based detection method

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If the piston is made of plastic material, then the manufacturing cost is reduced and production is simplified, but the structural rigidity and strength are insufficient

Engineering Contradiction:

Improvemanufacturing cost and production simplicityVSAvoidstructural rigidity and strength

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The patent creates a composite structure with a plastic piston body reinforced by an integrated metallic skeleton. The plastic provides cost-effective molding and manufacturing simplicity, while the embedded metal skeleton supplies the necessary structural rigidity and strength to withstand hydraulic pressures and mechanical loads

Inventive Principle:

Principle #40Composite materials

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 plastic primary piston reduces manufacturing costs while effectively detecting braking requests through the kinematic chain, maintaining structural integrity and functionality comparable to aluminum pistons.

Implementation Method 1

at least one magnet is incorporated into the body of the piston... incorporates a position detection means that is connected to the kinematic chain associating the primary piston with the brake pedal

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Implementation Method 2

the plastic material is filled with ferrite fibers in the volume surrounding the integrated element

Methodology Applied

Scientific EffectFerromagnetic reinforcement: Ferromagnetic Powder

Implementation Method 3

the plastic material is filled with glass fibers

Methodology Applied

Scientific EffectGlass fiber reinforcement: Composite Materials

Data Source

PatentUS9908517B2Primary piston of a tandem master cylinder

Publication Date: 2018.03.06 ROBERT BOSCH GMBH

AI summary

A primary piston of a tandem master cylinder includes: a body provided with a skirt, having in the rear thereof a cavity for the plunger and the push rod connected to the brake pedal and in the front a cavity defining the primary chamber. The piston is made of a plastic material and at least one magnet is built into the body of the piston.