Brake Shoe Friction Lining Assembly with Wear-Limited Projections

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The assembly of two-part friction linings on drum brake brake shoes is prone to errors, and there is a risk of the radial projection contacting the brake drum's friction surface during severe wear, leading to improper alignment and potential braking issues.

Innovation Solution

The brake shoe and friction lining design incorporates recesses and radial projections on the lining carrier and partial linings, respectively, where the radial extent of the projection is equal to or less than the lining thickness difference, ensuring correct assembly and preventing contact with the brake drum during wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If radial projections are provided on the lining carrier to engage with recesses in partial linings for assembly guidance, then assembly precision is improved, but there is a risk that the radial projection may contact the brake drum's friction surface during severe wear of the friction lining

Engineering Contradiction:

Improveassembly precisionVSAvoidprojection contact with brake drum

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The radial extent of the projection is specifically dimensioned to be equal to or less than the lining thickness difference between new and worn conditions. This parameter change ensures that as the lining wears down, the projection recedes from the friction surface rather than contacting it, eliminating the harmful effect while preserving the assembly guidance function

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The design anticipates severe wear conditions beforehand by sizing the projection to be non-intrusive even when the lining is completely worn. This prior cushioning approach prevents the projection from ever contacting the brake drum friction surface, eliminating potential harmful effects before they can occur

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Ease of repair

If the friction lining is constructed in two parts for easier replacement, then ease of repair is improved, but assembly errors may occur during installation

Engineering Contradiction:

Improvelining replacementVSAvoidassembly accuracy

Core Design Contradiction:

Ease of repairVSManufacturing precision

Solution Approach 1:

The radial projections and recesses are positioned asymmetrically relative to the partial linings, creating a unique orientation for each piece. This asymmetry ensures that the partial linings can only be assembled in the correct position, eliminating assembly errors while maintaining the ease of replacement benefit

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The radial projections on the lining carrier nest into corresponding recesses in the partial linings, creating a precise interlocking fit. This nesting mechanism guides the partial linings into their correct positions during assembly, ensuring high assembly accuracy while allowing easy installation and replacement

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentEP1748211B1Brake shoe for a vehicle drum brake and a corresponding two piece friction lining

Publication Date: 2010.02.24 BPW BERGISCHE ACHSEN KG

Figure 1~4

AI summary

The brake unit comprises a curved carrying element (1) and a friction lining attached to its outer surface. The friction lining is assembled of two identical parts (10a,10b) which can be interchanged if required and are positioned beside each other. The parts (10a,10b) are provided with recesses (21a,21b) or projections (20) to be engaged with complementary recesses (21a,21b) or projections (20) located at the outer surface of the carrying element (1).