Brake Disc Braking Band Recess Layout for Squeal Reduction
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Solution Overview
Problem
Existing braking bands for motor vehicles suffer from high-frequency noise or squeal during braking, and previous solutions with large windows or constant-height surfaces are not effectively adapted for vehicles other than motorcycles, as they reduce the braking surface area and do not completely eliminate squeals.
Innovation Solution
The braking band features radially outer edges with angularly offset radial recesses, which distribute pressure and friction forces, providing additional damping and modifying the mass distribution and stiffness to reduce vibrations and eliminate squeals, while maintaining the braking surface area for motor vehicles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If large windows are drilled in the braking band to reduce squeal, then high-frequency noise is reduced, but the braking surface area is considerably reduced
Solution Approach 1:
The patent applies local quality by creating radial recesses only at specific locations (radially outer edges) of the braking band rather than drilling large windows throughout. This localized modification reduces squeal by affecting vibration modes in specific areas while preserving the overall braking surface area for effective braking action.
Solution Approach 2:
The patent employs asymmetry by positioning radial recesses at radially outer edges with angular offset between opposite sides of the braking band. This asymmetric configuration disrupts the symmetry of vibration modes that cause squeal, while maintaining sufficient braking surface area unlike the symmetric large windows in prior art.
2Area of stationary object
If constant-height braking surfaces are used, then the braking surface area is maintained, but squeals are not completely eliminated
Solution Approach 1:
The patent modifies the constant-height surface by introducing local variations through radial recesses at the radially outer edges. These localized modifications are sufficient to disrupt squeal-generating vibrations while maintaining the overall constant height and maximum braking surface area.
Solution Approach 2:
The patent directly addresses mechanical vibration by designing radial recesses that modify the vibration modes of the braking band. The recesses create additional damping and alter mass distribution to suppress the high-frequency vibrations that cause squeal during braking.
3Object-generated harmful factors
If radial recesses are provided in radially outer edges, then squeals are eliminated and disc stability is enhanced, but the structural complexity increases
Solution Approach 1:
The patent segments the braking band structure by introducing discrete radial recesses at specific locations rather than modifying the entire structure. This segmentation approach eliminates squeal through targeted modifications while keeping the overall structure simple and manufacturable.
Solution Approach 2:
The patent changes geometric parameters by introducing radial recesses with specific dimensions and angular offsets. These parameter modifications are sufficient to eliminate squeal and enhance stability while maintaining a relatively simple structure that does not require complex manufacturing processes.
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 effectively reduces high-frequency squeals and vibrations, enhances disc stability, and maintains the braking surface area, thereby improving braking performance without compromising pad interaction.
Implementation Method 1
A distribution variation of the pressure and friction forces which disturbs the pad movement, by bringing about an additional damping also, for example, in the disc plane
Implementation Method 2
In the high-frequency squeals generated by the band, a considerable vibration of the disc in its plane is detected which, thanks to the proposed solutions, is surprisingly obviated
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A braking band (1) of a disc for brake disc, surprisingly capable of a particularly noiseless braking action, comprises a body (2) having a pre-established rotation axis (a), said body being restrained in the axial direction by a first braking surface (3) adapted to be rubbed by a brake pad, and a second braking surface (4), opposed to the first one, and adapted to be rubbed by a brake pad, in order to exert a braking action on a vehicle; said braking surfaces (3, 4) axially define a braking volume (5) of said body; said first braking surface comprising a first radially inner edge (6) which radially defines said surface on the rotation axis side, said first inner edge being inscribed by a first inner edge line (7) which is closed and lying on a circumference with radius (R1i) of a pre-established dimension; said first braking surface comprising a first radially outer edge (8) which radially defines said surface on the opposed side to the rotation axis, said first outer edge being circumscribed by a closed first outer edge line (9); said second braking surface comprising a second radially inner edge (10) which radially defines said surface on the rotation axis side, said second inner edge being inscribed by a second inner edge line (11) which is closed and lying on a circumference with radius (R2i) of a pre-established dimension; said second braking surface comprising a second radially outer edge (12) which radially defines said surface on the opposed side to the rotation axis, said second outer edge being circumscribed by a closed second outer edge line (13); said first and second outer edges being parts of a disc outer edge (14) which radially defines said disc on the opposed side to said rotation axis; where at least one axial portion (15) of said disc outer edge being circumscribed by a closed disc edge line (16) comprises at least one angular portion (A, B, C, D) which is radially recessed towards the rotation axis to form an edge outer recess (17) entering said braking volume.