Floating Caliper Guide Pin Sealing for Low-Friction Travel
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Solution Overview
Problem
Existing floating calipers face challenges in providing adequate sealing for secondary guide pins, leading to dirt ingress and corrosion, while maintaining caliper movement and reducing frictional resistance, especially in vehicles with limited space.
Innovation Solution
A floating caliper design featuring a sealing arrangement with a tubular-shaped sealing boot that creates a channel between the pin seat and guide pin, allowing for reduced size and increased travel, while maintaining guiding and sealing functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a secondary guide pin passes completely through the caliper in a through-hole arrangement, then the caliper can move axially to accommodate pad and disc wear, but dirt and water can ingress along the guide pin surface causing corrosion
Solution Approach 1:
The sealing boot is nested within the caliper body structure, forming a protective envelope around the guide pin. The boot is received by a seat in the caliper body and extends along the guide pin, creating a nested configuration that protects the pin from environmental contaminants while allowing axial movement.
Solution Approach 2:
A flexible sealing boot made of elastomeric material is used to cover the guide pin. This flexible shell conforms to the pin surface and creates an effective seal against dirt and water ingress, while still permitting the guide pin to slide axially within the boot during caliper movement.
2Object-affected harmful factors
If a sliding seal is provided on the secondary guide pin to prevent dirt accumulation, then corrosion is reduced, but frictional resistance increases and the guide pin must be made of expensive stainless steel
Solution Approach 1:
The sealing boot acts as a flexible film that covers the guide pin surface without requiring a sliding seal mechanism. The boot material itself provides the sealing function through its elasticity and conformability to the pin surface, eliminating the need for additional sliding seal components and reducing frictional resistance.
Solution Approach 2:
The sealing boot is made from cost-effective elastomeric material rather than expensive stainless steel. The boot can be replaced if necessary, providing an economical solution that protects the guide pin from corrosion without requiring the guide pin itself to be made of expensive corrosion-resistant material.
3Object-affected harmful factors
If the sealing arrangement is positioned to seal the guide pin throughout the entire stroke, then protection is maximized, but the caliper movement is constrained in vehicles with limited space
Solution Approach 1:
The sealing boot provides protection for the guide pin along its stroke path, but the design accepts that the boot itself does not extend beyond the caliper body in the retracted position. The sealing action is sufficient to protect the pin during movement, and the boot can be positioned to provide adequate sealing without requiring excessive travel distance.
Solution Approach 2:
The sealing arrangement is designed to be dynamic rather than static - the sealing boot flexes and moves with the guide pin during caliper operation. This dynamic configuration allows the seal to maintain contact with the pin throughout the stroke while accommodating the limited space available in the vehicle.
Data Source
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AI summary
A floating caliper (1) comprising a caliper body (2) arranged straddling a brake disc (3), said brake disc (3) rotating about a rotation axis (X-X), which defines an axial direction (A-A), a radial direction (R-R) orthogonal to said axial direction (A-A), and a circumferential direction (C-C) orthogonal to both said axial direction (A-A) and said radial direction (R-R); wherein said caliper body (2) is movably supported in the axial direction (A-A) at least at one guide pin (4); said at least one guide pin (4) comprises a pin sliding portion (5) of predetermined pin axial extension (L); said caliper body (2) comprises a pin seat (6), which slidingly accommodates a portion of said pin sliding portion (5); said pin seat (6) has a predetermined pin seat axial extension (S); said floating caliper (1) further comprises a sealing arrangement (7) interposed between said pin seat (6) and said guide pin (4); said sealing arrangement (4) comprises a tubular-shaped sealing arrangement body (8) made in one piece, which crosses said entire pin seat (6); said sealing arrangement (4) comprises a sealing arrangement outer surface (9) in contact with said pin seat (6); said sealing arrangement (4) comprises a sealing arrangement inner surface (10) in contact with said pin sliding portion (5); wherein at least either of said sealing arrangement outer surface (9) or sealing arrangement inner surface (10) comprises an axial extension (C), which is smaller than the pin seat axial extension (S) or the length of the pin sliding portion (L), respectively, creating, in at least one position of the floating caliper (1) during the axial sliding thereof, at least one sealing arrangement channel (11) between said sealing arrangement (4) and said pin seat (6) or said pin sliding portion (5); and wherein said at least one sealing arrangement channel (11) is open, i.e. it comes out of said pin seat (6).