Shimless Brake Pad With High Loss Factor Layers
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Solution Overview
Problem
Conventional vehicle brake pads with shims have limited vibration damping capacity outside a narrow temperature range, leading to deteriorated noise, vibration, and harshness (NVH) characteristics, and require additional components that increase production costs and complexity.
Innovation Solution
A vehicle brake pad design without a shim, featuring a back plate layer made of a Fe—Mn-based damping alloy, an acryl-based adhesive layer, and an underlayer with specific compositions, all with a loss factor of 0.2 or higher, ensuring effective noise damping across a wide temperature range of -100 to 300°C and improved bonding force between layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a shim is used to improve noise damping, then vibration damping capacity is improved within a narrow temperature range, but the temperature range for effective damping is limited and NVH characteristics deteriorate outside this range
Solution Approach 1:
The patent combines the damping functions of the shim, underlayer, and back plate into an integrated multi-layer structure. The underlayer (first damping layer) and back plate (second damping layer) work together to provide continuous damping across a wide temperature range, eliminating the need for a separate shim component while maintaining and extending damping effectiveness.
Solution Approach 2:
The patent employs composite material design with the underlayer containing rubber particles (10-30 parts by weight) dispersed in a resin matrix, creating a viscoelastic composite that maintains damping properties across extreme temperatures from -100°C to 300°C, far exceeding the narrow temperature range of conventional shims.
2Object-generated harmful factors
If a shim is added to improve vibration damping, then noise characteristics are improved, but device complexity and production cost increase
Solution Approach 1:
The damping function previously requiring a separate shim component is merged into the existing underlayer and back plate structure. The underlayer serves dual purposes as both a bonding interface and a primary damping layer, while the back plate provides secondary damping, eliminating the need for an additional shim part and simplifying the overall structure.
Solution Approach 2:
The underlayer is designed to perform multiple functions: it acts as an adhesive bonding layer between the friction material and back plate, serves as the primary damping layer with high loss factor, and provides thermal insulation. This multi-functionality eliminates the need for separate shim components while maintaining noise damping performance.
3Ease of manufacture
If conventional materials are used for the underlayer and back plate, then manufacturing is simple, but bonding force between layers is insufficient and durability is reduced
Solution Approach 1:
The underlayer uses a composite material system consisting of a resin base (polyester resin, polyurethane resin, or acrylic resin) with dispersed rubber particles (10-30 parts by weight per 100 parts resin). This composite provides both high bonding strength to the back plate and friction material, and high damping capacity through the viscoelastic rubber particles.
Solution Approach 2:
The patent optimizes specific material parameters including rubber particle content (10-30 parts by weight per 100 parts resin), rubber particle size (0.1-10 μm), and resin type selection to achieve the optimal balance between bonding force, damping capacity, and thermal stability across the -100°C to 300°C temperature range.
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 design enhances noise damping capacity over a broader temperature range, reduces production costs, and improves braking accuracy and stability by increasing the shear strength of the brake pad without the need for a shim, thus simplifying the structure and maintaining damping performance.
Implementation Method 1
at least one of the back plate layer, the adhesive layer, and the underlayer has a loss factor of 0.2 or higher... to damp noise of a frequency range of 200 to 20,000 Hz
Implementation Method 2
The underlayer may contain 10 to 30 wt % of binder, 20 to 30 wt % of filler, 5 to 20 wt % of reinforcing agent, 15 to 40 wt % of elastomer
Implementation Method 3
a friction material layer combined with a front surface of the underlayer and generating friction by coming into contact with the disk of the brake
Data Source
AI summary
A vehicle brake pad includes a back plate layer, an underlayer, an adhesive layer that mediates between the back plate layer and the underlayer, and a friction material layer, wherein the vehicle brake pad does not include a shim and wherein at least one of the back plate layer, the adhesive layer, and the underlayer has a loss factor of 0.2 or higher, calculated according to the following Equation 1, at temperatures from −100 to 300° to damp noise of a frequency range of 200 to 20,000 Hz at temperatures from −100 to 300°: (Equation 1) Loss factor η=(f2−f1)/f0, where η is a loss factor, f0 is a noise frequency, f1 is a minimum value of amplitude of a noise frequency when a noise level is reduced by 3 dB, and f2 a maximum value of amplitude when the noise level is reduced by 3 dB.