Plastic Primary Piston with Metal Insert for Brake Master Cylinder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing master cylinders experience noise issues due to rapid piston movement, leading to brake fluid pressure dropping below atmospheric pressure, and current solutions require complex and costly production methods for improved performance.
Innovation Solution
A plastic primary piston with a metal insert, molded in phenolic resin filled with glass fibers, is used, featuring a spherical cap shape for push rod accommodation and spring centering, allowing for overmolding and enhanced mechanical resistance, reducing material thickness, and enabling complex shape production through injection molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If aluminum pistons with special shapes are used to improve performance, then braking performance is improved, but production cost and complexity increase significantly
Solution Approach 1:
The patent uses a composite structure combining plastic material for the piston body with a metal insert (spherical cap and centering portion) embedded within. This allows the piston to achieve the necessary mechanical strength and specific shapes for performance while being manufactured through injection molding, significantly reducing production complexity compared to traditional aluminum pistons with complex machining requirements.
2Ease of manufacture
If piston material thickness is reduced to lower cost, then production cost decreases, but mechanical resistance and strength are compromised
Solution Approach 1:
The composite structure of plastic body with metal insert provides high strength-to-thickness ratio. The metal insert (spherical cap and centering portion) reinforces critical areas, allowing the overall piston wall thickness to be reduced while maintaining or improving mechanical resistance. This enables cost-effective manufacturing with thinner walls that still meet strength requirements.
Solution Approach 2:
The metal insert is strategically placed only in critical areas (spherical cap for push rod contact and centering portion for spring alignment) rather than throughout the entire piston. This localized reinforcement provides necessary mechanical strength where needed while keeping overall material usage and cost low, allowing thin-walled construction in non-critical areas.
3Speed
If rapid piston movement is allowed for responsive braking, then braking response speed improves, but noise generation increases due to water hammer effect
Solution Approach 1:
The patent changes the material parameters of the piston by using plastic material with specific viscoelastic properties instead of traditional aluminum. This material substitution provides natural damping characteristics that absorb shock waves and reduce the water hammer effect, allowing rapid piston movement for responsive braking while significantly reducing noise generation. The plastic material's inherent damping capacity transforms the harmful noise-generating rapid movements into quieter operation.
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 provides a cost-effective, mechanically robust, and noise-dampening primary piston that reduces material usage and production complexity, while maintaining mechanical strength and allowing for easy assembly and surface rectification, effectively addressing noise issues and improving brake master cylinder performance.
Implementation Method 1
The body of the piston is easily produced by injection molding in plastic material which allows the damping of the noise generated by the brake fluid (water hammer)
Implementation Method 2
The primary piston is preferably made of a thermosetting plastic and even more preferably of phenolic resin filled with glass fibers
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The subject of the invention is a master cylinder mounted primary piston (20) comprising at least one primary piston and one secondary piston mounted in the bore of the master cylinder. These pistons allow a pressure to be created. The primary piston (20) with a body (21) made of moulded plastic is fitted with a functional metal insert (22) and the said insert has the shape of a spherical cap (30) capable of accepting a push rod.