Brake Valve Pressure Control for Tractor-Trailer Safety

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Solution Overview

Problem

Existing brake systems in vehicle combinations, particularly agricultural vehicles, face challenges in ensuring safe braking and preventing unexpected braking due to pressure collapses in brake lines, leading to safety concerns.

Innovation Solution

A brake system with a pressure source connected to first and second brake lines, featuring a first clutch for coupling to the towing vehicle and a second clutch for the towed vehicle, along with a first and second shift valve assembly to manage high and low pressure, and a check valve to delay braking onset in case of pressure failure, allowing the driver to adjust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a second brake line is provided as a backup brake system, then braking reliability is improved, but unexpected abrupt braking occurs when pressure collapses

Engineering Contradiction:
Improvebraking reliabilityVSAvoidunexpected abrupt braking
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The control unit monitors pressure in the first brake line and activates the second brake line before pressure collapse occurs. By detecting pressure changes in advance and preemptively engaging the backup brake system, the invention prevents unexpected abrupt braking while maintaining braking reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses pressure sensors to continuously monitor the pressure state in the first brake line and provides feedback to the control unit. This feedback mechanism enables the control unit to detect pressure changes and trigger the second brake line appropriately, preventing harmful abrupt braking while ensuring reliable braking operation.

Inventive Principle:
Principle #23Feedback

2Reliability

If pressure collapse is allowed to occur, then the second brake line activates as backup, but braking becomes uncontrolled and unexpected

Engineering Contradiction:
Improvebackup brake activationVSAvoidcontrolled braking
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control unit activates the second brake line before pressure collapse occurs by monitoring pressure changes in advance. This preliminary activation ensures that the transition to backup braking is controlled and expected by the driver, maintaining ease of operation while ensuring backup brake reliability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Continuous pressure monitoring provides feedback to the control unit, enabling it to detect pressure changes and control the activation of the second brake line. This feedback control ensures that braking remains controlled and predictable, preventing uncontrolled abrupt braking while maintaining backup brake reliability.

Inventive Principle:
Principle #23Feedback

3Object-affected harmful factors

If a check valve is installed to maintain pressure, then gradual braking is achieved, but system complexity increases

Engineering Contradiction:
Improvegradual controlled brakingVSAvoidbrake system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The control unit acts as an intermediary between the pressure monitoring system and the brake lines. It processes pressure information and controls the activation of the second brake line, achieving gradual controlled braking without requiring complex mechanical pressure maintenance devices like check valves in the brake lines themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention replaces mechanical pressure maintenance mechanisms (such as check valves in brake lines) with an electronic control system that uses pressure sensors and a control unit to manage brake activation. This substitution achieves gradual controlled braking while reducing mechanical system complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 system ensures gradual and controlled braking upon pressure collapse, enhancing safety by providing the driver with time to react and preventing abrupt braking interventions.

Implementation Method 1

the check valve allows the high pressure on the second brake line to be maintained at least temporarily

Methodology Applied
Scientific EffectCheck valve pressure retention: Valve

Data Source

PatentEP3632755B1Vehicle and tractor-trailer
Publication Date: 2021.04.28 CLAAS TRACTOR
  • EP3632755B1 patent drawingFigure 1~3

AI summary

A vehicle, in particular a towing vehicle (1), for forming a train with a towed vehicle (2), comprises: - a pressure source (3), - a first and a second brake line (5, 6) connected to the pressure source (3), - a first coupling (15) for coupling the first brake line (5) to a towed vehicle (2), - a second coupling (22) for coupling the second brake line (6) to the towed vehicle (2), - a first switching valve assembly (9) arranged in the first brake line (5) and having a port (12) facing the pressure source (3) and a port (13) facing the first coupling (15) in order to selectively supply the first coupling (15) with fluid under high pressure, - a second switching valve assembly (20) arranged in the second brake line (6) and having a port (33) facing the pressure source (3) and a port (13) facing the second coupling (22).to selectively supply the second coupling (22) with fluid under high pressure. The second switching valve arrangement (20) is configured to assume a closed state when the pressure at the port (33) facing the pressure source (3) is lower than at the port (13) facing the second coupling (22).