Braking Band Ventilation Duct Surface Structure

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Solution Overview

Problem

Existing ventilated disk brake bands experience inadequate air flow on the inner surfaces during braking, leading to inefficient cooling due to flow resistance and an attached air layer that reduces air contact with the surface.

Innovation Solution

A surface structure with alternating ridges and valleys on the inner surfaces of the ventilation duct, increasing air speed and reducing flow resistance by promoting turbulence and air mixing, with impressions having depths exceeding 0.3 mm and diameters between 2-5 mm, arranged to form various patterns such as grid-like or honeycomb.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the ventilation duct has a smooth inner surface, then the flow resistance is lower, but the air layer remains attached to the surface reducing cooling efficiency

Engineering Contradiction:
Improvesmooth surface manufacturingVSAvoidcooling efficiency
Core Design Contradiction:
Ease of manufactureVSTemperature

Solution Approach 1:

The patent applies local quality by creating impressions (local modifications) on specific portions of the inner surface of the ventilation duct. These impressions are not uniformly distributed but are strategically placed to create alternating ridges and valleys that locally disturb the air flow, promoting turbulence and mixing while maintaining smoother areas elsewhere.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent replaces the conventional smooth mechanical surface with a structured surface featuring impressions, ridges, and valleys. This substitution transforms the laminar flow regime into a turbulent one, enhancing heat transfer efficiency without requiring active mechanical intervention.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Productivity

If the air flow speed through the ventilation duct is increased, then the total flow rate increases, but the air layer detachment reduces the amount of air contacting the inner surface

Engineering Contradiction:
Improveair flow rateVSAvoidsurface cooling
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The patent creates mechanical disturbances in the air flow through the impressions, ridges, and valleys structure. These geometric features induce turbulence and periodic flow separation, which enhance mixing between the air layers and increase the amount of air contacting the inner surface, thereby improving cooling efficiency.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent changes the physical parameters of the air flow by introducing turbulence through the structured surface. This transforms the flow regime from laminar to turbulent, altering the flow characteristics to enhance heat transfer while maintaining acceptable flow resistance.

Inventive Principle:
Principle #35Parameter changes

3Temperature

If impressions with depth exceeding 0.3 mm are created on the inner surface, then air speed and turbulence increase, but the manufacturing complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidsurface structure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent applies partial action by creating impressions with specific depth ranges (exceeding 0.3 mm, preferably exceeding 0.5 mm, most preferably ranging between 0.5 mm and 1.0 mm) rather than modifying the entire surface uniformly. This targeted approach achieves the desired turbulence effect while limiting the overall structural complexity and manufacturing difficulty.

Inventive Principle:
Principle #16Partial or excessive action

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

Significantly increases the amount of air blowing on the inner surfaces, enhancing cooling efficiency and kinetic energy dissipation during braking.

Implementation Method 1

This speed increase entails an increase in the kinetic energy of the air, which results in small turbulences and local detachments of the air from the surface

Methodology Applied
Scientific EffectTurbulence: Turbulence

Implementation Method 2

This speed increase entails an increase in the kinetic energy of the air

Methodology Applied
Scientific EffectKinetic energy increase:

Implementation Method 3

the cooling effect of the internal ventilation of the ventilated braking bands depends, besides on the area of the inner surface of the ventilation duct, also and mainly on the amount of fresh air that blows on said inner surface during a braking action

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2102523B1Braking band of a disk for a disk brake
Publication Date: 2012.01.11 FRENI BREMBO SPA
  • EP2102523B1 patent drawingFigure 1
  • EP2102523B1 patent drawingFigure 2
  • EP2102523B1 patent drawingFigure 3a~3b

AI summary

A braking band (2) of a brake disk (1) comprises two plates (3, 3') which are connected by means of connecting elements (4) such as to internally form a ventilation duct (7) that is at least partially defined by inner surfaces (8, 81) of the plates (3, 31) and that extends from an inlet opening (10) that is radially internal relative to an axis of rotation (S) of the braking band (2) to an outlet opening (11) that is radially external relative to the axis of rotation (S). At least one of the inner surfaces (8, 81) comprises a plurality of impressions (15) that are arranged such as to define a surface structure with alternated ridges (16) and bottoms (17) in the flow direction from the inlet opening (10) to the outlet opening (11).