Drum Brake Shoe Support Structure for Noise Reduction
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Solution Overview
Problem
Drum brakes face challenges during assembly and service due to complex components like springs, clips, and linkages, and suffer from self-excitation issues leading to brake fade and noise, which are exacerbated by variations in friction coefficient and require more sensitivity compared to disc brakes.
Innovation Solution
A drum brake assembly design featuring a brake shoe support structure with a table and web, where the web is perpendicular to the friction lining, allowing secure placement without tools and eliminating complex components, guiding each brake shoe radially to avoid torque amplification and reduce noise and fade.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional drum brake components (springs, clips, linkages, adjusters) are used to hold brake shoes in position, then the brake shoes can be securely positioned, but the assembly and service process becomes complex and time-consuming
Solution Approach 1:
The patent combines multiple separate components (brake shoe, support structure, positioning features) into an integrated assembly where the brake shoe includes integrated positioning features that directly engage with the support structure, eliminating the need for separate springs, clips, linkages, and adjusters. This merging reduces component count and simplifies assembly operations.
Solution Approach 2:
The brake shoe includes self-positioning features such as positioning tabs or protrusions that automatically align and engage with corresponding recesses in the support structure during installation. This self-service mechanism eliminates the need for complex adjustment procedures and multiple components, allowing the brake shoe to position itself correctly without additional fastening operations.
2Power
If drum brake geometry is designed to amplify brake application force through self-excitation, then braking efficiency is improved, but sensitivity to friction coefficient variations increases leading to brake fade
Solution Approach 1:
The patent modifies the geometric parameters of the brake shoe and support structure to change the force transmission mechanism. Instead of relying on self-exciting tangential forces that amplify application force, the design uses directly applied radial forces through modified shoe geometry and positioning features, eliminating the amplification effect while maintaining reliable braking performance across varying friction conditions.
3Power
If drum brake geometry is designed to amplify brake application force through self-excitation, then braking efficiency is improved, but brake noise such as squeal is aggravated
Solution Approach 1:
The patent changes the geometric parameters and force application methodology to eliminate self-excitation. The modified brake shoe geometry and support structure positioning features create a direct force transmission path that avoids tangential braking forces on the lining surface, thereby eliminating the conditions that generate brake noise while maintaining adequate braking power.
4Reliability
If disc brake arrangement is used to avoid amplification effect and reduce sensitivity to friction variations, then brake fade resistance is improved, but cost increases
Solution Approach 1:
Instead of adopting disc brake geometry to eliminate amplification effects, the patent inverts the approach by modifying drum brake geometry to directly apply radial forces without self-excitation. This maintains the cost advantages of drum brake manufacturing while achieving the reliability characteristics of non-amplifying brake systems by fundamentally changing the force application mechanism within the drum brake configuration.
Data Source
AI summary
An illustrative example drum brake device includes a drum having an inner, braking surface. At least one brake shoe includes a friction lining and a support structure for the friction lining. The support structure includes a window having a first portion that is wider than a second portion. A shoe mount is configured to be received through the first portion of the window and engage the support structure adjacent the second portion of the window in a manner that resists movement of the brake shoe in two dimensions and allows selective movement of the brake shoe in a third dimension for allowing the friction lining to selectively engage the braking surface.