Disc Brake Pad Retention Spring Layout to Prevent Pad Rotation

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Solution Overview

Problem

Existing pad retention systems for disc brakes in motor vehicles fail to effectively prevent the rotation of brake pads during braking, leading to unwanted wear adjustments due to torque transmission and production-related tolerances.

Innovation Solution

The pad retention system positions pad retention springs radially outward, securing the brake pad in a form-fitting contact with the brake carrier horns, shifting the pivot point during torque application to prevent rotational movement and allowing for thermal expansion compensation and installation tolerance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the brake pad is allowed to move around a pivot point during braking, then the brake pad can accommodate torque transmission, but this leads to unwanted wear adjustment due to rotational movement

Engineering Contradiction:
Improvebrake pad movement capabilityVSAvoidwear stability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention inverts the conventional approach by positioning the pivot point not at the outlet-side carrier horn but at the inlet-side carrier horn. This reversal changes the rotational behavior during braking, allowing the brake pad to pivot in a controlled manner that prevents unwanted wear adjustment while maintaining adaptability to torque transmission.

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

Solution Approach 2:

The invention establishes a predetermined pivot point location at the inlet-side carrier horn before braking occurs. This preliminary positioning of the pivot point ensures that during braking, the brake pad rotates around a fixed reference point, preventing uncontrolled rotational movement and associated wear issues.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a positive locking mechanism is used to hold the brake pad in the brake pad channel, then rotational movement is restricted, but manufacturing tolerances require minimum clearance that reduces effectiveness

Engineering Contradiction:
Improvebrake pad positioning stabilityVSAvoidclearance requirement
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention introduces a pivot point as an intermediary element between the brake pad and the carrier horns. This pivot point acts as a mediator that allows controlled movement while maintaining stable positioning, effectively bridging the gap between the need for positioning stability and the reality of manufacturing tolerances requiring clearance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the parameter of pivot point location from the conventional outlet-side carrier horn to the inlet-side carrier horn. This parameter change fundamentally alters the behavior of the brake pad during braking, enabling it to accommodate manufacturing tolerances while maintaining positioning stability and preventing unwanted wear.

Inventive Principle:
Principle #35Parameter changes

3Strength

If the pad retention spring presses the brake pad towards the bridge part, then the brake pad is secured to the brake carrier, but this prevents form-fitting contact with the carrier horns

Engineering Contradiction:
Improvebrake pad retention forceVSAvoidform-fitting contact
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention inverts the direction of the retention spring force by positioning the pivot point at the inlet-side carrier horn instead of the outlet-side carrier horn. This inversion causes the spring force to press the brake pad against the inlet-side horn, creating form-fitting contact while maintaining secure retention.

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

Solution Approach 2:

The invention applies local quality by creating form-fitting contact specifically at the inlet-side carrier horn through the pivot point mechanism. This localized contact ensures reliable retention and prevents unwanted wear at the critical interface between the brake pad and the carrier horn.

Inventive Principle:
Principle #3Local quality

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

This configuration effectively inhibits brake pad rotation during braking by utilizing frictional forces and maintains a secure, form-fitting contact with the carrier horns, ensuring proper brake function and wear prevention.

Implementation Method 1

The pad retainer spring presses the brake pad against the brake carrier with a force FF

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

which, however, is prevented by the frictional force FR prevailing at the outlet-side brake carrier horn by the contact of the brake pad side against the outlet-side brake carrier horn

Methodology Applied
Scientific EffectFriction force: Friction

Data Source

PatentEP2812595B1Pad retention system of a disc brake of a motor vehicle
Publication Date: 2022.01.05 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP2812595B1 patent drawingFigure 1
  • EP2812595B1 patent drawingFigure 2
  • EP2812595B1 patent drawingFigure 3

AI summary

A pad retention system of a disc brake of a motor vehicle, in particular of a utility vehicle, has a brake caliper (1) which engages over a brake disc, a brake carrier (1) which is positionally fixed on the vehicle, said brake carrier having entry-side and exit-side carrier lugs (2, 3) and having a bridge part (4) which connects the carrier lugs (2, 3) to one another, at least one brake pad (5) which is provided with a pad carrier plate (51) and a friction pad fastened thereto and which is guided in a pad slot (7) formed by the carrier lugs (2, 3) and by the bridge part (4), wherein at least one of the carrier lugs (2, 3) of the pad carrier (1) and the support surface, adjacent thereto, of the pad carrier plate (51) can be fixed to one another in a positively locking manner with play, wherein the at least one brake pad (5) is held in the pad slot (7) under spring loading exerted by a pad retention spring (6) which extends transversely with respect to the axial direction of the brake disc and which is radially deflectable on the brake pad (5), wherein the at least one pad retention spring (6) is arranged such that the pad retention spring (6), in the assembled state, presses the brake pad (5) away from the bridge part (4) of the brake carrier (1) and against the carrier lugs (2, 3) without play.