Fiber-Reinforced Brake Drum for Lower Weight and High Load Capacity

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Solution Overview

Problem

Current brake drums for motor vehicles are heavy, which increases unsprung mass and negatively impacts driving performance and fuel efficiency, while existing lightweight solutions either compromise on load capacity or increase production costs.

Innovation Solution

A brake drum formed partially or entirely from high-temperature-resistant fiber-reinforced plastic with differently aligned fiber layers, incorporating support fibers and a metallic or ceramic friction ring for enhanced mechanical resilience and stability, and a curved transition to prevent fiber deformation, along with a fiber connection for cohesive force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If brake drums are made from traditional heavy materials (steel, cast iron), then load-bearing capacity and structural strength are ensured, but weight increases unsprung mass and reduces fuel efficiency

Engineering Contradiction:
Improvebrake drum weightVSAvoidload-bearing capacity
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The brake drum is constructed from fiber-reinforced plastic composite material consisting of a thermoplastic matrix reinforced with continuous fibers (glass, carbon, or aramid). This composite structure provides high strength-to-weight ratio, achieving both weight reduction and maintained load-bearing capacity. The fibers are embedded in the thermoplastic matrix to create a unified structural component that meets both weight and strength requirements.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameters by transitioning from metallic materials to polymer-based composite materials. The thermoplastic matrix provides ductility and toughness while the fiber reinforcement provides tensile strength, creating a material system with different but superior combined properties compared to traditional metals. This parameter change enables weight reduction while maintaining or improving mechanical performance.

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If brake drums are made from lightweight materials to reduce unsprung mass, then fuel consumption decreases and driving performance improves, but load capacity and structural stability may be compromised

Engineering Contradiction:
Improvefuel consumptionVSAvoidstructural stability
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The fiber-reinforced thermoplastic composite provides both lightweight properties for reduced fuel consumption and high structural stability for reliability. The continuous fiber reinforcement ensures consistent mechanical properties and structural integrity under braking loads, while the thermoplastic matrix binds the fibers into a stable, load-bearing structure that maintains dimensional accuracy and structural reliability.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The brake drum is designed as a one-piece monolithic structure formed from the composite material, eliminating joints, welds, or fasteners that could compromise structural reliability. This seamless construction ensures uniform material properties throughout and eliminates potential failure points, enhancing overall structural stability and reliability while maintaining lightweight characteristics.

Inventive Principle:
Principle #1Segmentation

3Weight of moving object

If fiber-reinforced plastic is used to reduce brake drum weight, then manufacturing cost may increase, but weight reduction benefits driving performance and fuel efficiency

Engineering Contradiction:
Improvebrake drum weightVSAvoidproduction cost
Core Design Contradiction:
Weight of moving objectVSEase of manufacture

Solution Approach 1:

The invention utilizes thermoplastic matrices instead of thermosetting resins, enabling the use of established thermoplastic processing technologies such as injection molding or extrusion. These technologies are well-developed and cost-effective in the plastics industry. The continuous fiber reinforcement can be incorporated using standard composite manufacturing techniques, making the production process economically viable despite the advanced material system.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The brake drum is manufactured as a one-piece molded component, eliminating the need for secondary assembly operations, fasteners, or joining processes. This monolithic construction reduces manufacturing steps, minimizes assembly costs, and improves production efficiency. The integrated design allows the entire brake drum to be formed in a single manufacturing cycle, offsetting the higher material costs through process simplification and reduced labor requirements.

Inventive Principle:
Principle #1Segmentation

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 achieves a significant weight reduction, improving driving performance and reducing fuel consumption while maintaining high load capacity and stability, even at elevated temperatures, without incurring significant cost penalties.

Implementation Method 1

By applying the brake, a brake lining is pressed essentially radially from the inside towards the brake drum, which rotates with the wheel. This dissipates the kinetic energy and converts it into heat.

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The resulting heat is absorbed by the brake drum and released into the surrounding air.

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

The resulting heat is absorbed by the brake drum and released into the surrounding air.

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3707405B1Brake drum for a vehicle drum brake
Publication Date: 2021.07.14 ROBERT BOSCH GMBH
  • EP3707405B1 patent drawingFigure 1
  • EP3707405B1 patent drawingFigure 2~5

AI summary

Disclosed is a brake drum (1) for a drum brake, in particular of a motor vehicle, comprising a cylindrical jacket (2) and a support pot (3) which axially adjoins the jacket and which has a hub ring portion (4) to be secured to a wheel hub, the monolithic brake drum (1) being made at least in part of a fiber-reinforced plastic.