Cast-Iron Brake Disk Surface Control for Judder Reduction
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Solution Overview
Problem
The judder phenomenon in brake systems occurs due to varying brake torque vibrations, which are exacerbated by inconsistent eutectic cell distributions on brake disk friction surfaces, leading to discomfort for passengers.
Innovation Solution
A brake disk with a friction surface formed of cast iron, featuring an average of no more than 300 eutectic cells per square centimeter and a deviation of no greater than 60 cells per square centimeter, manufactured through a casting and grinding process that controls eutectic cell exposure to minimize vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the brake disk is manufactured using conventional casting methods, then the manufacturing process is simple and cost-effective, but the eutectic cell distribution on the friction surface is inconsistent, leading to high brake torque vibrations and judder phenomenon
Solution Approach 1:
The invention applies preliminary action by performing grinding on the friction surface after casting to control the eutectic cell exposure. The grinding process is designed in advance to achieve the target eutectic cell density (200-400 cells/cm²) by removing a specific amount of material (0.5-3.0 mm), thereby ensuring consistent eutectic cell distribution before the brake disk is put into service. This preliminary treatment eliminates the inconsistency caused by conventional casting alone.
Solution Approach 2:
The invention changes the physical parameter of the friction surface by controlling the eutectic cell density through a combination of casting parameters (cooling rate, composition) and post-casting grinding depth. By adjusting the grinding depth to expose a controlled number of eutectic cells (200-400 cells/cm²), the friction characteristics are optimized to reduce brake torque vibrations. This parameter control transforms the inconsistent casting outcome into a precise friction surface property.
2Force
If the number of eutectic cells on the friction surface is increased, then the friction coefficient may increase, but the brake torque vibrations and judder phenomenon are exacerbated
Solution Approach 1:
The invention optimizes the eutectic cell density parameter to a specific range (200-400 cells/cm²) that balances friction coefficient and vibration reduction. Through controlled grinding, the invention removes excess eutectic cells from the surface while maintaining sufficient friction. This precise parameter control shows that neither too many nor too few eutectic cells are optimal; the specific range achieves the best compromise between friction force and vibration minimization.
Solution Approach 2:
The invention implements feedback by measuring the eutectic cell density on the friction surface and adjusting the grinding depth accordingly. The process monitors the number of eutectic cells exposed and modifies the material removal rate to achieve the target density (200-400 cells/cm²). This feedback mechanism ensures that the friction surface has the optimal eutectic cell distribution that minimizes brake torque vibrations while maintaining adequate friction.
3Object-generated harmful factors
If excessive grinding is applied to the friction surface to reduce eutectic cell exposure, then brake torque vibrations are reduced, but material is wasted and manufacturing cost increases
Solution Approach 1:
The invention optimizes the grinding depth parameter to achieve the minimum effective material removal. By controlling the grinding depth to expose only 200-400 eutectic cells/cm², the invention removes just enough material to reduce vibrations without excessive waste. This precise parameter control minimizes the loss of cast iron material while achieving the vibration reduction goal, representing an optimal balance point.
Solution Approach 2:
The invention applies partial action by performing selective grinding only on the friction surface rather than the entire brake disk. The grinding is limited to removing 0.5-3.0 mm of material specifically from the friction surface to control eutectic cell exposure, leaving the rest of the brake disk structure intact. This partial treatment reduces vibrations effectively while minimizing material waste compared to more extensive material removal approaches.
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 reduces maximum brake torque vibrations, minimizing the judder phenomenon and enhancing passenger comfort by stabilizing friction coefficients and reducing abrasive wear.
Implementation Method 1
an average of numbers per unit area of eutectic cells formed on surfaces of the sections
Implementation Method 2
grinding the friction surface of the brake disk in a thickness direction
Data Source
AI summary
Disclosed are a brake disk and a method for manufacturing the same. In particular, the brake disk may include a friction surface formed of cast iron, and the friction surface of the brake disk is divided into a plurality of sections in a circumferential direction. Preferably, an average of the numbers per unit area of eutectic cells formed on surfaces of the sections may not be greater than 300 ea/cm2.