Frustoconical Caliper Guide Pin for Disc Brake Noise Reduction
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Solution Overview
Problem
Disc brake systems with cylindrical columns experience vibration-induced noise due to stress and deformation, as the columns contact the bore walls during braking, leading to incomplete vibration isolation.
Innovation Solution
The columns are given a frustoconical shape with a smaller diameter end sunk deeper into the bore and a guide protuberance at the larger diameter end, which is optionally covered with rubber to reduce noise and ensure smooth guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cylindrical columns are used in the caliper, then the structure is simple and easy to manufacture, but the columns contact the bore walls during braking causing vibrations and noise
Solution Approach 1:
The patent applies asymmetry by transitioning from cylindrical (symmetric) columns to frustoconical (asymmetric) columns. The frustoconical shape creates an increasing gap between the column surface and the bore wall along the sliding direction, preventing contact at the critical region while maintaining guiding function. This asymmetric geometry resolves the contradiction by eliminating noise-generating contacts without compromising manufacturing feasibility.
Solution Approach 2:
The patent applies local quality by modifying only the critical region of the column (the sliding surface) while keeping other parts unchanged. The frustoconical shape specifically addresses the contact issue at the column-bore interface, creating a local geometric modification that prevents vibrations without requiring complete redesign of the entire column structure.
2Object-generated harmful factors
If the gap between columns and bore walls is increased to prevent contact, then vibrations are reduced, but the guiding precision during caliper movement deteriorates
Solution Approach 1:
The frustoconical shape creates an asymmetric gap distribution where the gap increases progressively in the sliding direction. This ensures that the critical region (where vibrations occur) has sufficient clearance, while the guiding region maintains appropriate contact or near-contact for precision.
Solution Approach 2:
The patent transitions from a zero-dimensional point contact (cylindrical column) to a one-dimensional line contact with varying gap (frustoconical column). This dimensional change allows the gap to vary along the sliding direction, simultaneously achieving vibration reduction and guiding precision.
3Object-generated harmful factors
If staircase columns are used to increase the gap, then some vibration contact is prevented, but the stepped structure creates additional stress concentration points
Solution Approach 1:
The patent replaces the stepped (discontinuous) geometry of staircase columns with a frustoconical (continuous curved) geometry. This continuous curvature eliminates stress concentration points at the steps while progressively increasing the gap to prevent vibrations. The smooth transition of the frustoconical surface distributes stresses uniformly, resolving the strength issue.
Solution Approach 2:
The patent changes the geometric parameter of the column from constant diameter (cylindrical) or stepped diameter (staircase) to continuously varying diameter (frustoconical). This parameter change allows smooth transition without abrupt discontinuities, eliminating stress concentrations while achieving the desired gap increase for vibration reduction.
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 frustoconical shape and rubber-covered protuberance effectively dampen vibrations and noise by minimizing contact stress and ensuring proper alignment, reducing mechanical stress and sound emission.
Implementation Method 1
The friction between the rubber and the internal wall of the bore allows for effective damping of the vibrations and noise generated during braking
Implementation Method 2
The frustoconical shape and rubber-covered protuberance effectively dampen vibrations and noise by minimizing contact stress
Data Source
Figure 1
Figure 2~3
AI summary
The device (1) has a cap (4) comprising a bore (13). A disk (3) is rotatably mounted with respect to a floating caliper (5) along a rotational axis (2). The guide pin has an end having a diameter less than a diameter of another end of the guide pin. The caliper has a tapered guide pin (14) inserted deeply in the bore of the cap. The former end of the guide pin is provided with a guiding projection that is covered with a hollow cylindrical rubber piece. A circular passage opening and an evacuation opening are formed on opposite parts of the piece.