Air Disc Brake Pad Geometry to Prevent Misassembly and Slipping
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Solution Overview
Problem
Existing air disc brake pad assembly methods fail to prevent incorrect insertion into brake calipers without adding weight or cost to the brake caliper, and can result in slipping due to wear, leading to misalignment and reduced brake performance.
Innovation Solution
The air disc brake pad features a thickened edge and a rear protrusion that opposes the friction material, preventing back-to-front insertion and mitigating slipping risks, without requiring additional material on the brake caliper, and includes abutment tabs for horizontal engagement to maintain alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a finger and notch arrangement is provided on the brake caliper to prevent incorrect insertion, then incorrect assembly is prevented, but the weight and cost of the brake caliper increases due to additional cast material
Solution Approach 1:
The brake pad is designed with an asymmetric rear protrusion that extends from the backplate in a direction opposing the friction material. This protrusion creates a one-way engagement feature that allows correct insertion into the brake caliper while preventing back-to-front insertion, eliminating the need for additional asymmetric features on the brake caliper itself
Solution Approach 2:
Instead of adding prevention features to the brake caliper (the receiving component), the invention inverts the approach by adding the prevention feature to the brake pad (the inserted component). The rear protrusion on the pad engages with a corresponding recess or space in the caliper, reversing which component carries the complexity
2Reliability
If additional cast material is added to the brake caliper carrier to create a finger for prevention, then incorrect insertion is prevented, but the cost of manufacturing increases
Solution Approach 1:
The asymmetric rear protrusion on the brake pad backplate creates a simple geometric feature that can be manufactured using standard pad forming processes, avoiding the need for additional casting operations or complex tooling modifications on the brake caliper
Solution Approach 2:
The invention transfers the manufacturing complexity from the brake caliper to the brake pad. Since brake pads are typically manufactured as complete assemblies with the friction material already bonded to the backplate, adding the rear protrusion during pad manufacturing is more cost-effective than modifying the caliper carrier
3Reliability
If a finger is added to the brake caliper carrier to prevent incorrect insertion, then assembly correctness is ensured, but material stresses during brake operation increase, reducing carrier life
Solution Approach 1:
The invention extracts the prevention function from the brake caliper carrier structure and relocates it to the brake pad. By removing the need for additional carrier material, the original carrier design maintains its optimized stress distribution and structural integrity during brake operation
Solution Approach 2:
The prevention feature is inverted from being part of the stationary carrier to being part of the moving pad assembly. This eliminates stress concentration points that would otherwise be created in the carrier by additional cast fingers or notches
4Reliability
If a non-symmetrical pad or carrier is used to prevent incorrect insertion, then assembly correctness is improved, but unusual pad wear patterns or non-uniform stresses occur during braking
Solution Approach 1:
The brake pad maintains overall symmetry for uniform wear and stress distribution, with the asymmetric rear protrusion being a localized feature confined to the backplate area. This localized asymmetry provides prevention functionality without affecting the symmetric contact surfaces that engage the brake disc
Solution Approach 2:
The rear protrusion creates a minimal asymmetric element on the otherwise symmetric pad design. This localized asymmetry is sufficient to prevent back-to-front insertion while maintaining symmetric braking surfaces for uniform wear patterns
Data Source
AI summary
An air disc brake pad 10 for inserting into a brake pad carrier 12, the brake pad 10 including a backplate 14 and a friction material 16 mounted on one side of the backplate 14, the pad periphery 30 including an inner side 20, an outer side 18 and first and second ends 22, 24; in which at least a portion of the pad periphery 30 includes a thickened edge 36, 38, the thickened edge 36, 38 extending in a direction opposing the friction material 16; and at least one rear protrusion 26, 28 is provided, the at least one rear protrusion 26, 28 extending from the backplate 14 in a direction opposing the friction material 16; and in which the depth of the at least one rear protrusion 26, 28 being greater than the depth of the thickened edge 36, 38. See FIG. 3.