Load-Dependent Brake Force Regulator for Agricultural Trailers

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Solution Overview

Problem

Agricultural trailers with higher axle and trailer loads, and increased driving speeds pose challenges for braking systems, as existing pneumatic brake systems require manual adjustment and lack load-dependent control, risking over-braking or inadequate braking, especially when trailers are lightly loaded or empty, and are not easily compatible with all tractor-trailer combinations.

Innovation Solution

A mechanically controlled, automatically load-dependent braking force regulator (ALB) is introduced, allowing manual adjustment of brake pressure through a connecting link and lever system, which can be easily adapted to different load conditions and equipment configurations, eliminating the need for complex input variables like suspension compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If manual brake force actuators with predefined switching positions are used, then the braking system can be operated without complex electronic components, but the operator must manually readjust the brake force when loading state changes, reducing ease of operation

Engineering Contradiction:
Improvebrake system complexityVSAvoidmanual readjustment requirement
Core Design Contradiction:
Device complexityVSEase of operation

Solution Approach 1:

The braking system automatically adjusts brake force based on axle load detection without requiring operator intervention. The control unit continuously monitors the axle load sensor and autonomously regulates brake pressure, eliminating the need for manual readjustment while maintaining system simplicity

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates a feedback mechanism where the axle load sensor continuously provides load information to the control unit, which then adjusts the brake force actuator accordingly. This closed-loop control enables automatic adaptation to changing load conditions without complex electronics

Inventive Principle:
Principle #23Feedback

2Ease of operation

If pneumatic brake systems with automatic load-dependent braking force control are used, then load status is automatically determined, but the system requires complex input variables such as suspension compression which are not available for certain working machines

Engineering Contradiction:
Improveautomatic load-dependent controlVSAvoidinput variable requirements
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention extracts the essential function of load detection by using only the axle load sensor, removing the requirement for suspension compression or other complex input variables. This simplified approach maintains automatic load-dependent control while making the system compatible with working machines that lack traditional suspension systems

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The system focuses on detecting load at the critical location where it directly affects braking - the axle load - rather than requiring system-wide measurements like suspension compression. This localized measurement approach simplifies the input requirements while maintaining effective load-dependent braking control

Inventive Principle:
Principle #3Local quality

3Reliability

If brake force actuator maximum value is set to limit braking pressure for lightly loaded trailers, then over-braking is prevented, but the trailer cannot be braked within desired limits when the towing vehicle is braked with medium or less pedal pressure

Engineering Contradiction:
Improveover-braking preventionVSAvoidbraking effectiveness
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system dynamically adjusts the brake force actuator maximum value based on real-time axle load detection. When the trailer is lightly loaded, the maximum value is reduced to prevent over-braking; when fully loaded, the maximum value is increased to ensure adequate braking effectiveness. This dynamic adaptation resolves the contradiction between preventing over-braking and maintaining braking effectiveness

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit changes the maximum brake force actuator value parameter based on detected axle load conditions. For lightly loaded trailers, the parameter is set to a lower value to prevent wheel locking; for heavily loaded trailers, the parameter is set to a higher value to ensure sufficient braking force, thereby maintaining both safety and effectiveness across different load conditions

Inventive Principle:
Principle #35Parameter changes

4Productivity

If higher axle and trailer loads with increased driving speeds are used, then transport capacity and efficiency are improved, but the braking system performance and reliability requirements increase significantly

Engineering Contradiction:
Improvetransport capacity and speedVSAvoidbraking system performance
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system uses continuous feedback from the axle load sensor to the control unit, which automatically adjusts brake force based on the detected load and speed conditions. This enables the braking system to maintain optimal performance and reliability even when transport capacity and driving speeds are increased

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The braking system autonomously adapts to varying load and speed conditions without operator intervention. The control unit continuously monitors axle load and automatically regulates brake pressure to match the current operating conditions, ensuring reliable braking performance across the full range of transport capacities and speeds

Inventive Principle:
Principle #25Self-service

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 provides stable and proportional braking across varying load conditions, ensuring the trailer remains within the desired brake band, reducing the risk of over-braking or under-braking, and allows easy retrofitting of existing systems without the need for expensive electronic components.

Implementation Method 1

a brake force actuator (4-1, 4-2, 4-3, 4-4) for reducing a control pressure (14) from a reservoir pressure connection (16) to a lower value, depending on a position of an adjusting lever (50)

Methodology Applied
Scientific EffectPressure reduction: Pressure Drop

Data Source

PatentEP3744590B1Brake system for an agricultural trailer and agricultural track assembly comprising a tractor and at least one trailer coupled with same
Publication Date: 2023.03.29 HORSCH MASCHEN
  • EP3744590B1 patent drawingFigure 1
  • EP3744590B1 patent drawingFigure 2A~2B
  • EP3744590B1 patent drawingFigure 3A~3B

AI summary

A pneumatically operated braking system (10) for a trailer or agricultural machinery is disclosed. The braking system (10) has a trailer brake valve (24) for applying an actuating force to brake cylinders (38, 40) assigned to at least two wheels of a trailer or agricultural machinery axle, depending on the braking force. An input control variable for load-dependent variation and/or throttling of a control pressure of the wheel brake cylinders (38, 40) can be manually set by means of an adjustable, automatically load-dependent brake force regulator (22), particularly depending on the load condition of the trailer or agricultural machinery. The invention also relates to an agricultural trailer having at least one axle and at least two braked wheels, and equipped with a pneumatically operated braking system (10).Furthermore, the invention relates to an agricultural work machine equipped with a braking system (10) operating with pneumatic pressure.