Floating Caliper Guide Pin Sealing for Compact Axial Travel
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Solution Overview
Problem
In floating calipers, the limited space in vehicles makes it difficult to achieve a reliable seal for the secondary guide pin, leading to dirt ingress and corrosion, while existing solutions either fail to prevent dirt entry or increase frictional resistance.
Innovation Solution
A secondary guide pin sealing arrangement with a reduced inner section and a tubular-shaped sealing boot that creates a free channel, allowing the caliper to move axially with reduced size constraints, improving the guiding function and preventing dirt ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a secondary guide pin is used in a floating caliper, then the caliper can move axially to accommodate pad and disc wear, but dirt and water can ingress through the guide pin causing corrosion
Solution Approach 1:
A sealing boot is introduced as an intermediary component between the guide pin and the environment. The sealing boot includes a sealed cavity that receives the guide pin and extends beyond it, creating a protective barrier that prevents dirt and water from reaching the guide pin while allowing the caliper to move axially along the pin.
Solution Approach 2:
The sealing boot is constructed as a flexible protective shell that envelops the guide pin. This flexible shell allows for the necessary axial movement of the caliper while maintaining a continuous seal that blocks contaminants from penetrating to the guide pin surface.
2Reliability
If the sealing arrangement is made longer to improve sealing, then dirt protection improves, but the caliper size increases and space availability is reduced
Solution Approach 1:
The sealing boot is designed to nest around the guide pin, with the sealed cavity receiving the pin and extending beyond its ends. This nested configuration allows the sealing function to extend beyond the guide pin length without proportionally increasing the overall caliper volume, as the sealing boot utilizes the existing guide pin structure as its core.
Solution Approach 2:
The sealing protection is extended in the radial dimension by having the sealing boot extend beyond the ends of the guide pin, rather than simply lengthening the pin itself. This dimensional approach provides enhanced sealing coverage while maintaining compact caliper dimensions.
3Object-affected harmful factors
If a sliding seal is provided on the guide pin, then dirt entry is limited, but frictional resistance increases and the guide pin must be made of expensive stainless steel
Solution Approach 1:
The harmful sliding seal interface is extracted from the system. Instead of having the caliper slide directly against a sealed surface on the guide pin, the design allows the caliper to move along the exposed guide pin while the sealing boot provides protection. This eliminates the high-friction sliding seal contact while maintaining dirt protection.
Solution Approach 2:
The guide pin can be made of less expensive materials since it is protected by the sealing boot rather than relying on expensive stainless steel to resist corrosion from direct exposure. The sealing boot acts as a sacrificial protective element that can be replaced if needed, while the guide pin itself uses more economical materials.
Data Source
AI summary
A floating caliper may have a caliper body where the caliper body is movably supported in an axial direction on at least at one guide pin. The guide pin may have a pin sliding portion. The caliper body may have a pin seat, which slidingly accommodates a portion of the pin sliding portion. The floating caliper may also have a sealing arrangement between the pin seat and the guide pin. A sealing arrangement outer surface or a sealing arrangement inner surface may have an axial extension, which is smaller than a pin seat axial extension or the length of the pin sliding portion, respectively, creating, in at least one position of the floating caliper during the axial sliding thereof, at least one sealing arrangement channel between the sealing arrangement and the pin seat or the pin sliding portion.