Spring Brake Release Pressure Control for Vehicle Towing Braking

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Solution Overview

Problem

Existing vehicle braking systems face challenges during towing, particularly when rapid braking occurs, as the pressure in the main air line escapes, causing the spring brake to be applied, which interferes with the pneumatic anti-skid's ability to optimize braking force, leading to suboptimal performance.

Innovation Solution

A device that incorporates both HL pressure-dependent and speed-dependent control of the spring storage release pressure, allowing the spring brake to be automatically applied during rapid braking while towing, preventing the spring brake from engaging when the vehicle is in motion by using a supply pressure from a compressed air device, and featuring an overlay protection mechanism to prevent braking force superimposition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the spring brake is controlled only by HL pressure during towing, then the brake release is simple, but the spring brake may engage during rapid braking while towing, interfering with pneumatic anti-skid performance

Engineering Contradiction:
Improvebrake release controlVSAvoidbraking performance during towing
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The control system monitors both HL pressure and vehicle speed parameters, and switches the spring brake release pressure source based on the vehicle state. When towing is detected (via speed signal), the system switches to supply pressure from the compressed air supply device, preventing spring brake engagement during rapid braking while maintaining simple HL-pressure-controlled release during normal operation.

Inventive Principle:
Principle #35Parameter changes

2Force

If the spring brake engages during rapid braking while towing, then braking force is increased, but the pneumatic anti-skid cannot optimize braking force, leading to suboptimal performance

Engineering Contradiction:
Improvebraking forceVSAvoidbraking optimization
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The control system uses feedback from the vehicle speed signal to determine whether the vehicle is in towing mode. When towing is detected, the system activates the supply pressure path from the compressed air supply device to prevent spring brake engagement, ensuring that the pneumatic anti-skid system can fully optimize braking force without interference from spring brake engagement.

Inventive Principle:
Principle #23Feedback

3Force

If both pneumatic brake and spring brake act on the same lever mechanism, then braking force is amplified, but mechanical load on the lever mechanism increases

Engineering Contradiction:
Improvebraking forceVSAvoidmechanical load on lever mechanism
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The control system preemptively prevents spring brake engagement by supplying pressure to the spring brake cylinder when towing is detected, before any potential brake force superimposition can occur. This preliminary anti-action avoids the harmful effect of excessive mechanical load on the lever mechanism while preserving the benefit of amplified braking force when needed.

Inventive Principle:
Principle #9Preliminary anti-action

4Reliability

If the spring brake is prevented from engaging during towing, then braking performance is optimized, but additional control complexity is introduced

Engineering Contradiction:
Improvebraking performanceVSAvoidcontrol system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control system uses the existing vehicle speed signal, already present for other vehicle functions, to detect towing mode. This multi-functional use of the speed signal avoids adding dedicated sensors or complex control logic, achieving optimized braking performance during towing while minimizing additional control complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Ensures optimal braking performance during towing by preventing the spring brake from engaging during rapid motion and reducing the mechanical load on the lever mechanism, thereby minimizing the risk of wheel blockage and ensuring effective braking force application.

Implementation Method 1

the spring force of the spring-loaded spring takes effect automatically

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

compressed air, which acts on the spring-loaded brake piston of the spring-loaded brake actuator via a flow path fed by a compressed air supply device, creates a spring-loaded release pressure

Methodology Applied
Scientific EffectCompressed air pressure: Pressure Increase

Implementation Method 3

at least one friction brake element with a brake pad

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4098500B1Spring storage control device and spring storage control method for vehicle braking device
Publication Date: 2024.03.13 SIEMENS MOBILITY GMBH
  • EP4098500B1 patent drawingFigure 1~2
  • EP4098500B1 patent drawingFigure 3

AI summary

The invention relates to a spring accumulator control device (214) for a device (201) for braking a vehicle (F), comprising a pressure control means (214a) configured to control a towing operation spring accumulator release pressure (pFSa) for at least one spring accumulator brake actuator (11) of a spring accumulator brake of the vehicle as a function of the pressure (pHL) in a main air line (HL) of the vehicle (F). To improve the operation of the vehicle during a towing operation, the pressure control means (214a) is also configured to control the towing operation spring accumulator release pressure (pFSa) as a function of a vehicle-related speed signal (Sv;Sn). The invention also relates to a corresponding spring accumulator control method.