Pneumatic Brake Adjuster with Spring Return

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Solution Overview

Problem

Existing pneumatically actuated disc brake adjustment devices face challenges with large installation space requirements and imprecise clearance settings, as they often depend on brake actuation and are subject to significant tolerances.

Innovation Solution

A pneumatically actuated disc brake adjustment device featuring a non-self-locking threaded drive with a piston and restoring spring, allowing for precise adjustment through defined infeed and return strokes, independent of brake actuation, and utilizing a splined section and axial needle bearings for space-saving design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a mechanically actuated adjusting device is used, then the brake pads can be adjusted to compensate for wear, but the device requires a relatively large amount of installation space

Engineering Contradiction:
Improvebrake pad wear compensationVSAvoidinstallation space
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the mechanically actuated adjusting device with a pneumatically actuated device that uses compressed air to drive a piston. This pneumatic system achieves the same brake pad adjustment function while occupying significantly less installation space, as the pneumatic actuator can be integrated into the existing brake caliper structure without requiring additional external mechanisms.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The invention utilizes the axial dimension within the brake caliper by positioning the piston and threaded drive mechanism along the axial direction of the brake disc. This allows the adjusting device to operate within the existing three-dimensional space of the caliper, effectively reducing the footprint without compromising the adjustment function.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a mechanically actuated adjusting device is used, then the brake pads can be adjusted, but the adjustment function depends on brake application

Engineering Contradiction:
Improvebrake pad wear compensationVSAvoidindependence from brake actuation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The pneumatic actuator is connected to the vehicle's compressed air supply system, allowing the adjusting device to be activated independently of the service brake application. Compressed air can be supplied to the piston through a separate control valve, enabling adjustment operations to be performed at any time without requiring the driver to apply the service brake.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system utilizes the vehicle's existing compressed air infrastructure to power the adjusting mechanism, making the adjustment function self-sufficient and independent of the brake actuation system. The pneumatic supply is already available in the vehicle, eliminating the need for additional power sources or complex control mechanisms.

Inventive Principle:
Principle #25Self-service

3Area of stationary object

If a pneumatically actuated adjustment device is used with smaller installation space, then it can be installed in the caliper back, but the exact clearance adjustment is subject to relatively high tolerances

Engineering Contradiction:
Improveinstallation spaceVSAvoidclearance adjustment precision
Core Design Contradiction:
Area of stationary objectVSMeasurement precision

Solution Approach 1:

The system performs a preliminary coarse adjustment phase where the piston moves the brake pads into approximate contact with the brake disc. Following this, a fine adjustment phase is executed where the threaded shaft mechanism provides precise incremental adjustments. This two-stage approach ensures that the final clearance setting achieves high precision despite the compact installation space and tolerances in component manufacturing.

Inventive Principle:
Principle #10Preliminary action

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

Enables precise adjustment of brake clearance with reduced tolerance influence, allowing for independent activation and compact installation, improving the accuracy and efficiency of brake pad and disc wear compensation.

Implementation Method 1

at least one return spring is provided, with which the piston in the cylinder can be moved in a second direction opposite to the first direction

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

the piston, which can be pressurized with compressed air, is inserted and which can be moved in a first direction by pressurizing with compressed air

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP3317556B1Adjustment device for a disk brake
Publication Date: 2019.09.04 KNORR BREMSE SYSTEME FUER NUTZFAHIZEUGE GMBH
  • EP3317556B1 patent drawingFigure 1

AI summary

The invention relates to an adjustment device (1) for a pneumatically actuatable disk brake for a vehicle, which adjustment device is designed to compensate wear between a brake lining or a plurality of brake linings and/or a brake disk, wherein the adjustment device has at least the following: a pneumatic actuator device (3), which has a cylinder (4), into which an axially movable piston (5) is inserted, to which compressed air can be applied and which can be moved in a first direction by application of compressed air; a non-self-locking threaded drive (10, 13, 14), which has a threaded nut (10) and a threaded shaft (13); wherein the piston (5) is coupled to the threaded nut (13) in a rotationally fixed manner and wherein the threaded shaft (13) rotatably extends through the threaded nut (10). Said adjustment device is distinguished in that at least one restoring spring (27, 41) is provided, by means of which the piston (5) can be moved in the cylinder (4) in a second direction opposite the first direction, and the adjustment device (1) is designed in such a way that the adjustment device performs an advancing stroke as a result of application of compressed air to the piston (5) and performs a restoring stroke in a spring-actuated manner as a result of the spring force of the at least one restoring spring (27, 41).