Speed-Dependent Trailer Brake Control Valve
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Solution Overview
Problem
Conventional braking systems for work vehicles do not allow independent control of trailer brakes at low speeds, as they are typically actuated simultaneously with service brakes, limiting the ability to steer the vehicle without engaging trailer brakes.
Innovation Solution
A system and valve assembly that utilize a pilot-operated check valve and control valve to regulate the flow of pressurized hydraulic fluid to trailer brakes, allowing actuation when both brake pedals are depressed at low speeds and when either pedal is depressed at high speeds, enabling independent control of service brakes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If trailer brakes are coupled to the same hydraulic circuit as service brakes, then trailer brakes can be actuated via brake pedals, but trailer brakes cannot be independently controlled at low speeds for steering purposes
Solution Approach 1:
The system dynamically switches between two operational modes based on vehicle speed: at low speeds, the trailer brake is decoupled from the service brake circuit to allow independent steering; at high speeds, the trailer brake is coupled to the service brake circuit for coordinated braking. This dynamic reconfiguration resolves the contradiction by adapting the system behavior to the operational context.
Solution Approach 2:
A control valve acts as an intermediary between the service brake circuit and the trailer brake, selectively connecting or disconnecting them based on speed-dependent control signals. This intermediary component enables the system to achieve both independent low-speed steering and coordinated high-speed braking without direct permanent coupling.
2Reliability
If trailer brakes are actuated simultaneously with service brakes, then braking effectiveness is improved at high speeds, but steering capability is reduced at low speeds
Solution Approach 1:
The system dynamically adjusts the connection state between service brakes and trailer brakes based on vehicle speed. Below a threshold speed, the trailer brake is disconnected to enable steering; above the threshold, it is connected to ensure braking effectiveness. This dynamic adaptation resolves the contradiction between steering capability and braking effectiveness.
Solution Approach 2:
The system changes the operational parameter of the trailer brake (from connected to disconnected) based on the vehicle speed parameter. This parameter change allows the system to optimize performance for different operating conditions: steering at low speeds and braking at high speeds.
3Device complexity
If conventional braking systems are used, then system simplicity is maintained, but speed-dependent control functionality is lacking
Solution Approach 1:
A control valve is introduced as an intermediary component between the existing service brake circuit and trailer brake. This valve adds speed-dependent control functionality without requiring complete redesign of the conventional braking system, thus balancing the addition of versatility with minimal increase in complexity.
Solution Approach 2:
The control valve serves multiple functions: it acts as a coupling device, a speed-dependent switch, and a coordinator between service brakes and trailer brake. This multi-functionality allows the system to gain advanced control capabilities while minimizing the number of additional components required.
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
Enables safe and efficient operation by allowing independent actuation of service brakes at low speeds without engaging trailer brakes, improving steering capabilities and reducing the risk of unintended trailer brake activation.
Implementation Method 1
a pilot-operated check valve provided in operative association with the secondary supply line. The pilot-operated check valve may be configured to be actuated from a closed position to an opened position to provide a flow path through the secondary supply line from the first input line to the control valve
Implementation Method 2
a control valve provided between an output line and the primary and secondary supply lines. The control valve may be movable between a first position, wherein the output line is in fluid communication with the primary supply line, and a second position, wherein the output line is in fluid communication with the secondary supply line
Implementation Method 3
pressurized fluid is supplied to the output line from the primary supply line for actuating the brake of the unit hauled by the work vehicle
Data Source
AI summary
A system for controlling a brake of a unit hauled by a work vehicle may generally include a valve assembly. When a speed of the work vehicle exceeds a predetermined speed threshold, the valve assembly may be configured to allow the brake to be actuated when first and second brake pedals of the work vehicle are depressed, either individually or simultaneously. However, when the speed of the work vehicle is less than the predetermined speed threshold, the valve assembly may only be configured to allow the brake to be actuated when both of the first and second brake pedals are depressed simultaneously.