Disc Brake Outboard Pad Locking for Reliable Pad Return

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Solution Overview

Problem

In vehicle disc brake systems, the outer brake pad often fails to return to its original position after brake actuation, leading to noise, heat generation, and premature wear due to insufficient clearance, and existing solutions relying on sheet metal springs are prone to wear and rattling.

Innovation Solution

A vehicle calliper disc brake with a mechanical locking mechanism using a dove tail sheet metal part and projections to securely attach the outboard brake pad to the calliper bridge, ensuring it returns to its original position and maintaining adequate clearance, eliminating the need for sheet metal springs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the outer brake pad is free floating and slides towards the brake disc during brake application, then the brake pad can contact the disc for braking, but the brake pad may not return to its original position after brake actuation causing noise, heat generation and premature wear

Engineering Contradiction:
Improvebrake pad contact with discVSAvoidbrake pad return position
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The brake pad assembly serves itself by integrating the retaining function directly into the pad structure through the dove tail profile. The brake pad maintains its own position relative to the calliper bridge without requiring external springs or separate retaining components, eliminating parasitic drag while ensuring proper contact during braking.

Inventive Principle:
Principle #25Self-service

2Reliability

If sheet metal springs are used to secure and spread the brake pads, then the brake pads can be held in position, but the sheet metal springs are prone to wear and may cause rattling and parasitic drag

Engineering Contradiction:
Improvebrake pad positioningVSAvoidwear and rattling
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The invention extracts and eliminates the sheet metal spring component from the brake pad assembly. By integrating the retaining function directly into the brake pad structure through the dove tail profile engagement with the calliper bridge, the harmful sheet metal springs that caused wear and rattling are completely removed from the system.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The retaining function previously performed by separate sheet metal springs is merged into the brake pad structure itself. The dove tail profile is an integral part of the brake pad assembly that provides both structural support and retention functionality, eliminating the need for separate spring components.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a mechanical locking means with dove tail sheet metal part and projections is used to attach the outboard brake pad, then the brake pad returns to its original position and clearance is maintained, but the device complexity increases

Engineering Contradiction:
Improvebrake pad return positionVSAvoidlocking mechanism structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The mechanical locking function is merged into the brake pad assembly itself through the dove tail profile. This integrated approach provides reliable positioning and return characteristics while avoiding the complexity of separate locking mechanisms, springs, or external retaining components.

Inventive Principle:
Principle #5Merging (Combining)

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 prevents parasitic drag and noise by ensuring the brake pad returns to its original position, reducing wear and eliminating the need for sheet metal springs, thus enhancing brake performance and longevity.

Implementation Method 1

The side sections are arranged to be resiliently displaced away from each other when contacted by the at least one projection to form a snap-on mechanical locking means

Methodology Applied
Scientific EffectMechanical Fastening: 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

Implementation Method 3

The at least one fluid actuator is arranged in the calliper housing to displace the at least one piston in order to actuate the disc brake

Methodology Applied
Scientific EffectHydraulic Pressure: Hydraulic Press

Implementation Method 4

The actuating means can be a hydraulically or pneumatically powered cylinder connected to a source of fluid power on-board the vehicle

Methodology Applied
Scientific EffectPneumatic Pressure: Pressure Increase

Data Source

PatentEP4100659B1Vehicle disc brake arrangement, brake pad and vehicle
Publication Date: 2024.05.22 VOLVO TRUCK CORP
  • EP4100659B1 patent drawingFigure 1
  • EP4100659B1 patent drawingFigure 2
  • EP4100659B1 patent drawingFigure 3

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. A first brake pad mounted to the at least one piston on the calliper piston side and a second brake pad (222) mounted to the second wall on the calliper bridge side. A mechanical locking means provided on the calliper bridge, whereby the second brake pad (222) is releasably attached to the second side wal on the calliper bridge side. The mechanical locking means comprises a dove tail sheet metal part (224) on the second brake pad (222) and at least one projection on the second wall of the calliper bridge).