Waveform Metallic Brake Shim for Squeal Damping
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Solution Overview
Problem
Conventional brake systems experience brake squeal and vibration due to uneven friction material contact, leading to hot spots and inconsistent brake torque, which existing shims attempt to address but often require viscoelastic layers with limited thermal durability and adaptability.
Innovation Solution
The introduction of shim structures made from high-temperature tempered metallic materials with waveform cross-sections, such as sinusoidal, triangular, or saw-tooth designs, that provide selective damping and thermal dissipation without viscoelastic layers, allowing for tunable characteristics to adapt to different braking pressures and applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional brake pads with friction material are used, then braking function is achieved, but brake squeal and vibration occur due to uneven contact
Solution Approach 1:
A shim is introduced as an intermediary component between the brake pad and caliper. This shim acts as a mediator that modifies the contact interface, providing a more uniform distribution of contact pressure and reducing the force-coupled excitation that causes brake squeal and vibration.
Solution Approach 2:
The shim changes the physical parameters of the contact interface by distributing contact pressure more evenly across the friction material. This parameter modification prevents uneven contact regions from developing, thereby eliminating the source of vibration and squeal while maintaining consistent brake torque.
2Force
If brake pads operate under high braking pressure, then braking force is sufficient, but hot spots develop on the rotor causing inconsistent brake torque
Solution Approach 1:
The shim serves as a thermal intermediary that helps distribute heat more evenly across the brake pad contact surface. By preventing localized high-pressure contact regions, the shim reduces the formation of hot spots on the rotor and ensures more uniform temperature distribution during high-force braking operations.
Solution Approach 2:
The shim modifies the pressure distribution parameter at the contact interface, which directly influences heat generation and distribution. By creating a more uniform pressure field, the shim prevents localized overheating and maintains consistent thermal conditions across the rotor surface.
3Object-affected harmful factors
If viscoelastic damping materials are used in brake shims, then noise and vibration are reduced, but high temperature durability is compromised
Solution Approach 1:
The invention uses a simple metallic shim without expensive viscoelastic coatings. While the shim itself is a durable metallic component, it provides sufficient damping through its geometric design and material properties, eliminating the need for temperature-sensitive viscoelastic materials that would degrade under high thermal conditions.
Solution Approach 2:
The patent replaces the viscoelastic material-based damping mechanism with a metallic shim that relies on geometric damping and rigid body mechanics. This substitution eliminates the temperature sensitivity of viscoelastic materials while maintaining effective noise and vibration reduction through alternative mechanical means.
4Object-affected harmful factors
If brake linings are made denser, then brake squeal is reduced, but manufacturing complexity and cost increase
Solution Approach 1:
Instead of modifying the backing plate structure or material density, the invention introduces a shim as an intermediary component that achieves squeal reduction. This approach maintains the simplicity of the backing plate manufacturing process while effectively addressing brake squeal through the added shim layer.
Solution Approach 2:
The solution segments the brake assembly into distinct functional components: the brake pad, the shim, and the caliper. By separating the damping function into a dedicated shim component rather than integrating it into the backing plate, the manufacturing process remains simple while achieving the desired noise reduction effect.
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
These shim structures effectively reduce brake squeal and vibration, maintain durability at high temperatures, and ensure consistent thermal dissipation, improving brake system performance across various vehicle types and operating conditions.
Implementation Method 1
shims add mass, even if minimally, to the brake linings which, in turn, dampens vibrations and oscillations by reducing reaction forces transmitted back into the brake piston
Implementation Method 2
the brake shim can act as a thermal barrier to ensure consistent temperatures across the entire face of the pad, minimizing rotor hot spots and uneven lining wear
Implementation Method 3
The shim structures described herein provide high temperature durability, superior thermal dissipation characteristics
Data Source
AI summary
Provided is a shim structure adapted to be interposed between a friction member and a forcing member configured to urge the friction member against a rotating member of a brake system. The shim structure includes a sheet member having opposing first and second surfaces defining a substantially uniform thickness of sufficient magnitude to not deform during urging of the friction member. There is no viscoelastic layer on the first or second surfaces. The first and second surfaces also define a waveform cross-section having an amplitude and a wavelength extending substantially the entire length of the sheet member; the amplitude and wavelength are of sufficient ratio to provide selective noise and vibration damping, isolation, and thermal dissipation for the brake system. Additionally, the amplitude and wavelength are configured to be variably tunable, providing different predetermined levels of noise and vibration absorption and attenuation. The wave-form cross-section is preferably sinusoidal.