Eccentric Guide Pin Assembly for Air Disc Brake Drag Reduction
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Solution Overview
Problem
Existing air disc brake systems experience brake drag due to incomplete release of brake pads, leading to premature wear of brake pads and rotors, and increased wear on guide pins and calipers.
Innovation Solution
The air disc brake system incorporates an eccentrically mounted guide pin with longitudinally spaced ends and a through hole with a center axis, allowing for adjustable eccentricity to reduce sliding force between the guide pin and caliper, thereby minimizing brake drag.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the caliper slides on guide pins with fixed distance mounting, then the structure is simple and easy to manufacture, but manufacturing tolerances and carrier flex cause increased slide force leading to brake drag and premature wear
Solution Approach 1:
The guide pin is made adjustable in position along the carrier, transforming from a fixed static mounting to a dynamic adjustable mounting. This allows the installer to optimize the guide pin position to compensate for manufacturing tolerances and carrier flex, reducing slide force and eliminating brake drag while maintaining manufacturing simplicity
Solution Approach 2:
The mounting distance parameter between guide pins and carrier is made variable rather than fixed. By allowing adjustment of this parameter, the system can optimize performance to compensate for tolerance variations without requiring tighter manufacturing tolerances or more complex assembly procedures
2Reliability
If manufacturing tolerances are tightened to reduce guide pin slide force, then brake drag is reduced, but manufacturing cost and complexity increase
Solution Approach 1:
Instead of tightening manufacturing tolerances, the invention changes the mounting parameter from fixed to adjustable. This allows normal tolerance ranges to be used in manufacturing while still achieving optimal performance through post-assembly adjustment, avoiding increased manufacturing precision requirements
Solution Approach 2:
The adjustment mechanism allows preliminary optimization of guide pin position during assembly to compensate for tolerance variations. This preliminary action of adjusting the position eliminates the need for tighter manufacturing tolerances while ensuring proper brake release
Data Source
AI summary
An air disc brake system includes a carrier having a mounting feature and a guide pin having longitudinally spaced first and second ends, a through hold having a first center axis and an outer cylindrical surface having a second center axis. The first and second axes are spaced apart a distance D such that the outer cylindrical surface and through hole are eccentric. A caliper includes a bore with spaced apart first and second ends. The guide pin is received in the bore, and the caliper is slidably mounted on outer cylindrical surface of the guide pin. A fastener is disposed in the through hole and includes a first end engaged with the mounting feature and a second end engaged with the guide pin. An eccentric guide pin, a tool for adjusting the eccentric guide pin, and methods of using and assembling the air disc brake system are also provided.