Drum Brake Installation Member Frequency Detuning
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Solution Overview
Problem
Existing drum brake systems in straddle-type vehicles, such as motorcycles and snowmobiles, suffer from brake squeal due to resonance between the brake drum and brake shoe, and existing solutions are complex, difficult to attach, and require multiple parts, making them cumbersome and inefficient.
Innovation Solution
A drum brake system featuring an installation member with distinct first and second portions, where the natural frequency between these portions differs from the shoe plate, allowing frictional vibration energy to be converted into heat energy, thereby attenuating vibrations and preventing brake squeal, with a simple construction that can be easily attached and retrofitted.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vibration-suppressing members are fitted around the brake drum using a band of annular elastic material, then brake squeal is prevented, but the device becomes difficult to service or replace after wheel assembly and requires multiple parts increasing complexity
Solution Approach 1:
The installation member is divided into a first portion fixed to the shoe plate and a second portion fixed to or pressed against the shoe plate, with a vibration-dampening portion between them. This segmentation allows the device to be attached using existing fastening structures without requiring additional bands or elastic materials, simplifying the overall construction while maintaining vibration suppression functionality
Solution Approach 2:
The installation member integrates multiple functions into a single component: it serves as both the mounting structure (replacing separate bands and elastic materials) and the vibration-dampening element. By merging the attachment mechanism and vibration suppression function into one piece, the device complexity is reduced from multiple parts to a single integrated component
2Object-affected harmful factors
If vibration-suppressing members are made larger to increase the weight of the brake drum, then brake squeal is prevented, but the available outside round surface area of the brake drum is limited
Solution Approach 1:
Instead of distributing weight uniformly around the brake drum, the vibration-dampening portion is strategically positioned at specific locations on the shoe plate where it most effectively interrupts vibration transmission. This localized approach achieves vibration suppression without requiring large surface area or excessive weight, fitting within the limited space available
3Object-affected harmful factors
If the natural frequency of brake components is adjusted by changing weights, then brake squeal is prevented, but the construction becomes complex requiring multiple components
Solution Approach 1:
The installation member is designed with specific dimensional parameters (length, width, thickness of the vibration-dampening portion) that directly determine its natural frequency. By adjusting these geometric parameters during manufacturing, the desired frequency characteristics are achieved without adding complex multi-component assemblies, maintaining ease of manufacture while preventing brake squeal
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
Effectively prevents brake squeal by converting vibration energy into frictional heat energy, simplifying the construction and attachment process, and reducing the number of parts required, while maintaining effective vibration attenuation.
Implementation Method 1
the natural frequency of a portion of the installation member between the first portion and the second portion is different from the natural frequency of the shoe plate... converting vibration energy into frictional heat energy
Data Source
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AI summary
A drum brake, and a straddle-type vehicle provided with a drum brake, has a simple construction that is capable of effectively preventing brake squeal. An installation member 80 is positioned adjacent a brake drum 30 in the wheel shaft direction. A shoe plate 40 is provided and brake shoes 50 are pivotable relative thereto. The installation member 80 has a first portion 81A and a second portion 81B. The first portion 81A is fixed to the shoe plate 40 or another member. The second portion 81B is fixed to or pressed against the shoe plate 40. The natural frequency of a portion of the installation member between the first portion 81A and the second portion 81B is different from the natural frequency of the shoe plate 40.