Trailer Switchover Valve for Overrun Brake Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle trailer energy recovery systems face challenges in providing sufficient braking force during heavy braking, require oversized and expensive components, and struggle with energy dissipation and control effort, especially when the energy store is full or during uneven road conditions.
Innovation Solution
A vehicle trailer with a hydraulic brake force transmission device featuring a switchover valve that activates or deactivates the overrun braking system based on drawbar thrust forces, combining electronic recuperative braking with an overrun braking system to ensure reliable and efficient braking with minimal control effort, eliminating the need for a clamping device and enhancing operational safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the braking forces of the recuperative braking system alone are used, then the system is simple and cost-effective, but the braking force is insufficient to meet legal requirements during heavy braking
Solution Approach 1:
The braking system is segmented into two independent parts: a recuperative braking system for normal operation and an overrun braking system for heavy braking. The switchover valve divides the brake line into separate pathways, allowing each system to operate independently based on drawbar thrust force levels, thus providing sufficient braking force without requiring an overly complex integrated system
Solution Approach 2:
The system dynamically switches between recuperative and overrun braking modes based on real-time drawbar thrust force conditions. The switchover valve automatically transitions between blocked and through-flow positions depending on whether the thrust force exceeds the limit value, enabling the braking system to adapt its complexity and capacity to actual operating conditions
2Reliability
If oversized generators and motors are used to provide sufficient braking force, then the braking reliability is improved, but the weight and cost increase significantly
Solution Approach 1:
Instead of using one oversized generator/motor unit, the system segments the braking function into two smaller systems: a standard-sized recuperative braking system for normal operation and a mechanically-actuated overrun braking system for heavy braking. This segmentation allows each component to be optimally sized for its specific function, reducing overall weight while maintaining braking safety
Solution Approach 2:
The overrun braking system replaces the need for oversized electromagnetic braking components with a mechanically-actuated system that uses the drawbar thrust force itself to activate the wheel brakes. This mechanical substitution eliminates the need for heavy-duty generators and motors, significantly reducing weight and cost while ensuring sufficient braking force during heavy braking conditions
3Reliability
If the clamping device is used to block the drawbar, then the braking control is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The mechanical clamping device is replaced with a hydraulically-controlled switchover valve that responds to drawbar thrust force conditions. The valve automatically switches between blocked and through-flow positions based on hydraulic pressure changes caused by variations in drawbar thrust, providing reliable braking control without the complexity of mechanical clamping mechanisms and their associated mounting and adjustment requirements
Solution Approach 2:
The system uses hydraulic pressure as an intermediary to detect drawbar thrust force conditions and automatically control the switchover valve position. This hydraulic control mechanism provides precise and reliable braking control while being simpler to manufacture and integrate than mechanical clamping devices, as it leverages the existing hydraulic brake system infrastructure
4Measurement precision
If the electronic control device operates at extremely high speed, then the control precision is improved, but the system complexity and cost increase
Solution Approach 1:
The switchover valve automatically responds to drawbar thrust force conditions through inherent hydraulic pressure changes, eliminating the need for high-speed electronic control devices. The system uses the physical principles of hydraulic pressure transmission and valve response to self-regulate braking mode transitions, providing precise control based on actual thrust force levels without requiring complex electronic measurement and control systems
Solution Approach 2:
High-speed electronic control and measurement systems are replaced with a mechanically-responsive hydraulic valve system. The switchover valve directly responds to hydraulic pressure changes caused by drawbar thrust force variations through purely mechanical/hydraulic means, providing accurate and timely braking mode transitions without the complexity, cost, and power requirements of high-speed electronic control devices
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 provides a reliable, cost-effective, and simple braking system that ensures high operational safety and efficiency by automatically switching between recuperative and wheel brakes based on drawbar thrust forces, maintaining braking performance even when the energy recovery system fails, and allowing safe reversing without the overrun brake system interference.
Implementation Method 1
a brake line (14) which is connected to the brake cylinder (13), in which a switchover valve (17) is arranged that can be switched between a blocked position, in which the brake line (14) is closed, and a through-flow position, in which the brake line (14) is open for the transmission of brake pressure
Implementation Method 2
a switchover valve (17) arranged in a brake line (14) which connects the brake cylinder (13) to the wheel brakes (7), the switchover valve (17) being switched to a blocked position, in which the brake line (14) is closed, when the energy recovery device (21, 22) is functioning properly
Data Source
Figure 1~3
Figure 4
Figure 5~6
AI summary
A vehicle trailer (1) with an overrun brake system and a hydraulic brake force transmission device has a changeover valve (17) for activating and deactivating the overrun brake system, which is switched to a locking position when the vehicle trailer (1) is moving forward and the drawbar thrust force is below a certain drawbar thrust force limit value, in which it closes a brake line (14) between a brake cylinder (13) and wheel brakes (7), while when moving forward and the drawbar thrust force is above this drawbar thrust force limit value it is switched to a flow position in which the brake line (14) is open to transmit brake pressure to the wheel brakes (7).