Disc Brake Caliper Pad Locking to Prevent Parasitic Drag

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Solution Overview

Problem

Existing disc brake calipers with free-floating outer brake pads suffer from noise, heat generation, and premature wear due to inadequate clearance between the brake pad and disc, leading to parasitic drag.

Innovation Solution

A vehicle calliper disc brake system with a mechanical locking means using a dove tail sheet metal part and projections to securely attach the outboard brake pad to the calliper bridge, ensuring proper positioning and clearance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the outer brake pad is made free-floating to allow movement during braking, then the brake application force is improved, but the brake pad fails to return to its original position causing noise, heat generation, and parasitic drag

Engineering Contradiction:

Improvebrake application forceVSAvoidbrake pad return position reliability

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The brake pad assembly serves itself by integrating the retaining function directly into the pad structure through the dome-shaped protrusion and recess mechanism. The outboard brake pad's dome-shaped protrusion automatically engages with the recess in the calliper bridge, eliminating the need for separate retaining components and enabling the pad to self-return to its correct position after braking without manual intervention or additional springs.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The retaining function is merged with the brake pad structure itself by forming a dome-shaped protrusion on the pad and a corresponding recess in the calliper bridge. This integration combines the braking surface and positioning mechanism into a unified assembly, allowing the pad to both apply braking force and maintain proper clearance through its own geometric features rather than requiring separate retaining components.

Inventive Principle:

Principle #5Merging (Combining)

2Stability of the object's composition

If sheet metal springs are used to secure and spread the brake pads, then the brake pad positioning is improved, but the springs are prone to wear and cause rattling and parasitic drag

Engineering Contradiction:

Improvebrake pad positioning stabilityVSAvoidspring durability and noise-free operation

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The problematic sheet metal springs are completely extracted from the brake assembly and replaced by a geometric engagement mechanism. The dome-shaped protrusion on the outboard brake pad and the corresponding recess in the calliper bridge eliminate the need for separate spring components, removing the source of wear, rattling, and parasitic drag while maintaining stable brake pad positioning through direct geometric contact.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the wear-prone sheet metal springs with a simple geometric engagement feature that has no moving parts to wear. The dome-shaped protrusion and recess create a fixed, maintenance-free connection that eliminates the need for replaceable spring components, reducing long-term maintenance requirements and improving reliability.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Device complexity

If the outer brake pad is free-floating, then the device complexity is reduced, but insufficient clearance between brake pad and disc causes parasitic drag and premature wear

Engineering Contradiction:

Improvebrake assembly complexityVSAvoidparasitic drag and premature wear

Core Design Contradiction:

Device complexityVSObject-generated harmful factors

Solution Approach 1:

The brake pad assembly is segmented into distinct functional features: the dome-shaped protrusion on the outboard brake pad and the corresponding recess in the calliper bridge. This segmentation allows the pad to maintain a fixed, precise position relative to the disc while still allowing controlled movement during braking, eliminating parasitic drag from insufficient clearance without requiring complex retaining mechanisms.

Inventive Principle:

Principle #1Segmentation

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution ensures the outer brake pad automatically returns to its original position after brake actuation, preventing noise, heat, and parasitic drag, while reducing wear and eliminating the need for sheet metal springs.

Implementation Method 1

The protrusion is arranged to form a snap-fit connection with a recess in the calliper bridge when the brake pad is mounted in use

Methodology Applied

Scientific EffectSnap-fit mechanical connection: Mechanical Fastener

Implementation Method 2

The brake pads comprise a brake lining arranged for frictional contact with the brake disc

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS12292091B2Vehicle disc brake arrangement, brake pad, and vehicle

Publication Date: 2025.05.06 VOLVO TRUCK CORP

AI summary

A vehicle calliper disc brake comprising a brake disc connected to a vehicle wheel and having inboard and outboard side surfaces and a rotational axis; an actuator arranged in a calliper housing to displace at least one piston to actuate the disc brake; the calliper housing having facing first and second side walls on opposite sides of the brake disc, where the first side wall has at least one piston slidably mounted in a cavity between the side walls and where the second side wall is part of a calliper bridge extending from the first wall and spanning the brake disc.