One-Piece Austempered Brake Element for Lower Unsprung Mass
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Solution Overview
Problem
Conventional brake elements require separate materials for friction and fastening portions, leading to increased unsprung mass and potential screeching in vehicle brakes, while also being heavier and less efficient in terms of damping and strength.
Innovation Solution
A one-piece brake element is produced using a casting method from gray cast iron with lamellar graphite, where both the friction and fastening portions are austempered to form bainite, allowing for a unified component with high tensile strength and inherent damping, reducing weight and minimizing screeching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate materials are used for friction portion and fastening portion, then functional requirements are met, but unsprung mass increases and manufacturing complexity increases
Solution Approach 1:
The patent merges the friction portion and fastening portion into a single monoblock brake disk structure, eliminating the need for separate materials and assembly. This unified structure reduces unsprung mass while maintaining the functional requirements of both portions through optimized material distribution and heat treatment processes.
Solution Approach 2:
The brake disk is designed as a multi-functional component where a single structure performs both friction braking and fastening functions. The monoblock design integrates the friction surface and mounting features into one piece, reducing the number of parts and overall weight while ensuring reliable performance of both functions.
2Ease of manufacture
If conventional heat treatment is used, then manufacturing process is simple, but tensile strength and damping properties are insufficient
Solution Approach 1:
The patent applies specific heat treatment parameters (austenitizing temperature, austempering temperature and time) to transform the microstructure of the brake disk material. By controlling these thermal parameters, the process achieves superior tensile strength and damping properties while maintaining manufacturing feasibility through a standardized heat treatment workflow.
Solution Approach 2:
The heat treatment process utilizes phase transitions of the metal material, specifically transforming austenite to bainite through controlled cooling. This phase transition enables the brake disk to achieve enhanced mechanical properties including high tensile strength and improved damping characteristics, resolving the contradiction between simple manufacturing and superior strength.
3Weight of moving object
If wall thickness is reduced to lower weight, then unsprung mass decreases, but structural stability may be compromised
Solution Approach 1:
By optimizing the wall thickness parameters within specific ranges (friction portion: 2.0-4.0mm, fastening portion: 1.5-4.5mm) and combining them with advanced heat treatment, the patent achieves a balance between weight reduction and structural stability. The controlled microstructure from heat treatment compensates for the reduced thickness, maintaining strength and stability.
Solution Approach 2:
The patent creates a composite microstructure through heat treatment, transforming the homogeneous cast iron into a refined bainitic structure. This microstructural composite provides enhanced strength-to-weight ratio, allowing thinner walls to maintain structural stability while reducing overall brake element weight.
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 method results in a lighter brake element with reduced unsprung mass, enhanced damping, and improved strength, minimizing brake noise and extending service life through the use of a single bainite material for both portions.
Implementation Method 1
the blank is subjected to austenitizing at a predefined austenitizing temperature, and wherein the austenitized blank is subjected to austempering
Implementation Method 2
the austenitized blank is subjected to austempering at a predefined austempering temperature
Data Source
AI summary
A method is disclosed for producing a brake element, in particular a brake disk or brake drum, which has a friction portion and a fastening portion, wherein a blank for at least the friction portion is produced by a casting method from gray cast iron with lamellar graphite, wherein the blank is subjected to austenitizing at a predefined austenitizing temperature, and wherein the austenitized blank is subjected to austempering at a predefined austempering temperature. The friction portion and the fastening portion is produced in one piece, and that the fastening portion is produced with a wall thickness of at least 1.5 and at most 4.5 mm.