Hydraulic Disc Brake Parking Lock With Secondary Piston Actuation

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Solution Overview

Problem

Existing hydraulically controlled disc brakes with parking brakes require high electrical energy consumption and prolonged time to achieve locking with high hydraulic forces, which is inefficient and not optimal for quick engagement.

Innovation Solution

The design incorporates a secondary hydraulic cavity and piston that applies additional axial thrust to the primary piston, combined with a non-reversible mechanical transmission for the locking wheel, allowing for efficient locking with minimal electrical energy using a controlled electric motor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main hydraulic chamber is used for parking brake actuation with electromechanical locking, then the brake can be locked in parking position, but high electrical energy consumption and prolonged locking time occur

Engineering Contradiction:

Improveparking brake lockingVSAvoidelectrical energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The hydraulic system is segmented into two independent chambers: the main hydraulic chamber for service braking and a secondary hydraulic chamber for parking brake actuation. This segmentation allows the parking brake to use a dedicated hydraulic circuit with a secondary piston, eliminating the need for high electrical energy consumption associated with electromechanical locking of the primary piston while maintaining reliable parking brake functionality.

Inventive Principle:

Principle #1Segmentation

2Reliability

If the main hydraulic chamber is used for parking brake actuation, then the brake can be locked in parking position, but prolonged locking time occurs

Engineering Contradiction:

Improveparking brake lockingVSAvoidlocking time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The hydraulic system is segmented into two independent chambers: the main hydraulic chamber for service braking and a secondary hydraulic chamber for parking brake actuation. This segmentation allows the parking brake to use a dedicated hydraulic circuit with a secondary piston, enabling rapid hydraulic actuation without the prolonged locking time associated with electromechanical systems.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses hydraulic actuation through a secondary hydraulic chamber and secondary piston to apply the parking brake force. Hydraulic systems provide rapid and forceful actuation, significantly reducing the locking time compared to electromechanical means, while maintaining reliable and secure parking brake engagement.

Inventive Principle:

Principle #29Pneumatics and hydraulics

3Force

If high hydraulic forces are applied to the piston for parking brake, then secure locking is achieved, but high electrical energy consumption is required

Engineering Contradiction:

Improvehydraulic force on pistonVSAvoidelectrical energy consumption

Core Design Contradiction:

ForceVSUse of energy by moving object

Solution Approach 1:

The invention uses hydraulic actuation through a secondary hydraulic chamber and secondary piston to apply the parking brake force. Hydraulic systems provide rapid and forceful actuation, significantly reducing the locking time compared to electromechanical systems, while maintaining reliable and secure parking brake engagement.

Inventive Principle:

Principle #29Pneumatics and hydraulics

Solution Approach 2:

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

This solution enables the disc brake to lock in the parking position with minimal electrical energy consumption and in the shortest time, maintaining high hydraulic forces, thus improving energy efficiency and engagement speed.

Implementation Method 1

a secondary piston (82) mounted to slide axially in a sealed manner in a secondary hydraulic cavity (24S) in which it delimits a secondary hydraulic chamber (24S) and capable of cooperating with the piston rod (120) to apply to the primary piston (16) an additional hydraulic force for actuating the parking brake

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a primary piston (16) mounted to slide axially in a sealed manner in a primary hydraulic cavity (24P) in which it delimits a primary hydraulic chamber (24P) and capable of cooperating with an associated brake pad to apply to the latter a primary braking effort when the primary hydraulic chamber (24P) is supplied with pressurized fluid

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Data Source

PatentEP3087288B1Hydraulic control disk brake comprising a hydraulic actuation parking brake

Publication Date: 2021.02.24 CHASSIS BRAKES INT BV

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AI summary

The invention relates to a disk brake that comprises a caliper (12), a main piston that is slidably mounted in a main hydraulic cavity of the caliper, a piston rod (120), and a wheel (140) for axially locking the piston rod (120). Said disk brake is characterized in that the locking wheel (140) is rotated by an electric motor (166) via an irreversible mechanical transmission (176, 144) in such a way that the locking wheel (140) is kept rotationally stationary when an output shaft (168) of the electric motor (166) is not rotated.