Electrohydraulic Brake Release Layout for Intermittent Pressure Hold

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing electro-hydraulic brake release devices are large, heavy, and inefficient due to continuous operation requirements, leading to thermal and maintenance issues, with limited effectiveness in short release and braking intervals.

Innovation Solution

A compact brake release device design where the pump unit is integrated within a functional block, eliminating the need for a separate hydraulic housing and allowing intermittent operation, with a check valve and 2/2-way valves for fail-safe functionality and pressure control, and a pressure relief valve to prevent overloading.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If centrifugal pumps are operated continuously during brake application/release, then the brakes can be kept in the open state, but the device size and weight increase significantly

Engineering Contradiction:
Improvebrake release reliabilityVSAvoidbrake release device weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The pump is operated intermittently rather than continuously. The control unit activates the pump only when the braking element needs to be released, and deactivates it when the release pressure is achieved or when braking is required. This periodic operation eliminates the need for continuous pump rotation, significantly reducing the drive motor size and overall device weight while maintaining reliable brake release functionality.

Inventive Principle:
Principle #19Periodic action

2Reliability

If centrifugal pumps operate continuously to maintain brake release pressure, then brake release is reliable, but thermal problems occur due to constant drive loading

Engineering Contradiction:
Improvebrake release reliabilityVSAvoiddrive motor temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The drive motor operates intermittently based on brake release requirements rather than continuously. The control unit monitors system pressure and activates the pump only when release pressure is needed, allowing the motor to cool down between operations. This eliminates continuous thermal loading and associated thermal problems.

Inventive Principle:
Principle #19Periodic action

3Force

If large effective areas are used on actuating pistons to compensate for low pump pressure, then brake release force is sufficient, but the device volume increases

Engineering Contradiction:
Improvebrake release forceVSAvoidbrake release device volume
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The system generates high pressure through the pump rather than relying on large piston areas. The control unit regulates pump operation to achieve the specific pressure needed for brake release, allowing the use of compact actuators with smaller effective areas while maintaining sufficient release force.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If shaft seals are used in continuous operation, then hydraulic fluid containment is maintained, but seal problems occur requiring maintenance

Engineering Contradiction:
Improvehydraulic fluid containmentVSAvoidmotor serviceability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The pump and its shaft seals operate intermittently rather than continuously. This reduced operational duty cycle significantly decreases seal wear and extends seal life, reducing maintenance frequency. When maintenance is needed, the motor can be accessed more easily since it doesn't require complete hydraulic fluid removal for service.

Inventive Principle:
Principle #19Periodic action

5Reliability

If wet rotor motors are used to minimize shaft seal problems during continuous operation, then seal reliability improves, but hydraulic fluid must be removed before motor servicing

Engineering Contradiction:
Improveshaft seal reliabilityVSAvoidmotor serviceability
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The pump operates intermittently rather than continuously, reducing shaft seal wear and extending maintenance intervals. The reduced operational stress on seals maintains their reliability without requiring wet rotor motor configuration, preserving motor serviceability.

Inventive Principle:
Principle #19Periodic 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

The solution results in a more compact, reliable, and energy-efficient brake release device with reduced maintenance needs, capable of effective pressure control and safe operation, including during power failures, with enhanced operational safety and reduced thermal issues.

Implementation Method 1

a pump unit (113) which is set in motion by the electric drive unit (200), the pump unit (113) being designed to pressurize and convey hydraulic medium into the actuating cylinder arrangement (400)

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

a specific pressure acts on the actuating piston surface, which in turn exerts a specific actuating force on the linkage and neutralizes the (re)actuating force of the brake spring

Methodology Applied
Scientific EffectHydraulic force amplification: Hydraulic Press

Implementation Method 3

After a certain operating pressure has been built up in the cylinder, this pressure is maintained via suitable switching valves

Methodology Applied
Scientific EffectCheck valve pressure retention: Valve

Implementation Method 4

a spring force acts on braking elements via a force-amplifying lever system

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 5

a spring force acts on braking elements via a force-amplifying lever system, which in turn act on a corresponding braking body

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3003807B2Electrohydraulic brake release device and brake system
Publication Date: 2024.07.24 DELLNER BUBENZER GERMANY GMBH
  • EP3003807B2 patent drawingFigure 1A
  • EP3003807B2 patent drawingFigure 2~3
  • EP3003807B2 patent drawingFigure 4A~4B

AI summary

The invention relates to an electrohydraulic brake release device (1) comprising an actuating cylinder arrangement (400), a tank module (300) for receiving a hydraulic medium, an electric drive unit (200) and a functional unit (100) having a pump assembly (113). The pump assembly (113) is arranged in a recess (111) provided in the functional unit (100), which recess is in communication with the tank module (300), is functionally connected to the actuating cylinder arrangement (400) by way of a conduit arrangement (150, 160, 170, 171, 172, 180, 190) and by way of a bearing carrier cover (115) is sealed off from a dry-running drive motor (210, 211) of the electric drive unit (200). The invention further relates to a brake system comprising a brake release device of this kind.