Air Disc Brake Pad Geometry for Insertion and Slip Prevention

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Solution Overview

Problem

Existing air disc brake pad assembly methods are prone to incorrect insertion and wear-related issues, leading to increased material stress, weight, and cost, as well as potential slipping of brake pads due to non-uniform wear patterns and excessive wear allowance.

Innovation Solution

The air disc brake pad features a thickened edge and a rear protrusion on its backplate, which prevents incorrect insertion by abutting the brake disc if inserted incorrectly and mitigates slipping by providing additional engagement with the brake caliper, reducing material stress and weight while maintaining alignment even when abutment tabs fracture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a finger and notch arrangement is provided to prevent incorrect insertion, then assembly correctness is improved, but carrier weight and cost increase due to additional cast material

Engineering Contradiction:
Improveassembly correctnessVSAvoidcarrier weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The brake pad is designed with asymmetric features: a thickened edge at the front and a rear protrusion at the back. This asymmetry ensures that the pad can only be inserted in the correct orientation, as the thickened edge and protrusion will not align with the carrier's receiving features when inserted incorrectly. This eliminates the need for additional material on the carrier while maintaining foolproof assembly.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

Instead of modifying the carrier to prevent incorrect insertion (the conventional approach), the invention inverts the approach by modifying the brake pad itself. The thickened edge and rear protrusion on the pad create a mechanical interference that prevents incorrect insertion, transferring the complexity from the carrier to the pad.

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If additional cast material is added to the carrier to create a finger for prevention, then assembly correctness is improved, but material stresses during brake operation increase, reducing carrier life

Engineering Contradiction:
Improveassembly correctnessVSAvoidcarrier life
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The asymmetric design of the brake pad with its thickened edge and rear protrusion prevents incorrect insertion without requiring additional material on the carrier. This maintains the carrier's original structural integrity and stress distribution, preserving its service life while ensuring assembly correctness.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The invention extracts the prevention function from the carrier and relocates it to the brake pad. By placing the thickened edge and rear protrusion on the pad, the carrier is relieved of the need to have additional material or features, thereby maintaining its original strength and durability characteristics.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a non-symmetrical pad or carrier is used to prevent incorrect insertion, then assembly correctness is improved, but unusual pad wear patterns and non-uniform stresses occur during braking

Engineering Contradiction:
Improveassembly correctnessVSAvoidunusual wear patterns
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The brake pad maintains overall symmetry for uniform wear and stress distribution, but introduces localized asymmetric features (thickened edge and rear protrusion) only where needed for prevention. The symmetric portions of the pad continue to provide uniform contact with the disc, while the localized asymmetric features prevent incorrect insertion without affecting wear patterns.

Inventive Principle:
Principle #3Local quality

4Reliability

If the permissible pad and disc wear allowance is exceeded, then the worn pad can slip between the disc and brake pad carrier, but providing a thicker edge and rear protrusion mitigates this risk

Engineering Contradiction:
Improveprevention of slippingVSAvoidpad structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The brake pad uses localized thickening at the edge and a rear protrusion feature only where needed to prevent slipping, rather than increasing the thickness of the entire pad. This maintains simplicity while providing the necessary mechanical interference to prevent the pad from slipping out during excessive wear.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP4428388A1Air disc brake pad
Publication Date: 2024.09.11 MEI BRAKES LTD
  • EP4428388A1 patent drawingFigure 1
  • EP4428388A1 patent drawingFigure 2a~2b
  • EP4428388A1 patent drawingFigure 3

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.