Drum Brake Airflow Path for Stable Shoe-to-Drum Clearance
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Solution Overview
Problem
Drum brakes in vehicles experience non-symmetrical pressure application, leading to inconsistent distance between brake shoes and the drum, causing partial contact and resulting in incorrect braking performance during vehicle travel.
Innovation Solution
Incorporating an air flow path within the drum brake system to maintain a constant distance between the brake shoes and the drum using aerodynamic effects, with varying air flow path diameters and arrangements to separate the linings from the friction surface, and utilizing a restoring member to provide elastic force for maintaining this distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional drum brake structure is used, then braking force is generated by friction, but non-symmetrical pressure is applied to the drum causing inconsistent distance between brake shoes and drum
Solution Approach 1:
An air layer is introduced as an intermediary substance between the brake shoe lining and the drum friction surface. This air layer acts as a mediator that maintains a consistent gap, preventing direct contact and ensuring symmetrical pressure distribution during braking operations.
Solution Approach 2:
The patent utilizes pneumatic principles by creating an air flow path between the brake shoe and drum. The air pressure and flow characteristics are controlled to maintain a stable air cushion, ensuring consistent spacing and symmetrical force application during brake operation.
2Productivity
If brake shoes are positioned close to drum for effective braking, then braking efficiency improves, but partial contact occurs during travel causing drag torque
Solution Approach 1:
The patent replaces the traditional mechanical contact-based braking system with a pneumatic field-based system. Instead of direct mechanical contact between brake shoes and drum, an air layer is used to transmit force, eliminating friction-based drag torque during non-braking travel conditions while maintaining braking efficiency when activated.
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 ensures a consistent distance between brake shoes and the drum, reducing residual drag torque, improving fuel efficiency, preventing premature wear, and eliminating the need for complex mechanical parts, while also supporting cooling and dust removal through air flow.
Implementation Method 1
the drum has an air flow path allowing air flow formed inside the friction surface such that the lining and the friction surface are separated by the air flow
Data Source
AI summary
A brake apparatus for a vehicle includes a drum configured to rotate together with a wheel of the vehicle, a pair of brake shoes to which linings for rubbing against a friction surface on an inner circumferential side of the drum are attached, and a wheel cylinder disposed to contact one end of each of the pair of brake shoes and configured to operate the pair of brake shoes outwardly by receiving braking hydraulic pressure, and the drum has an air flow path allowing air flow formed inside the friction surface such that the lining and the friction surface are separated by the air flow.