Electrohydraulic Brake Valve with Integrated Overpressure Limiting
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Solution Overview
Problem
Electrohydraulic brake valves can experience overpressure issues due to software or valve driver failures, potentially leading to unsafe brake system failures, costly repairs, and increased risks with additional pressure limiting devices.
Innovation Solution
An integrated pressure limiting device is coupled to a modulating valve and a solenoid assembly within the electrohydraulic brake valve, using a pre-loaded spring to mechanically limit output pressure and prevent overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pressure limiting device is added between the electrohydraulic brake valve and the vehicle brakes, then overpressure protection is improved, but device complexity and cost increase
Solution Approach 1:
The pressure limiting device is merged with the electrohydraulic brake valve by integrating the spring mechanism directly into the valve body. The spring is positioned between the solenoid plunger and the valve spool, combining the limiting function with the existing valve structure rather than adding a separate external device.
Solution Approach 2:
The spring mechanism serves multiple functions: it acts as both a return spring for the valve spool and a pressure limiting device. This multi-functionality eliminates the need for separate components, reducing overall system complexity while maintaining overpressure protection.
2Reliability
If the vehicle brakes have a pressure rating equal to or higher than the potential brake pressure, then overpressure protection is improved, but cost increases
Solution Approach 1:
The spring is pre-loaded to a specific force that corresponds to the maximum safe brake pressure. This preliminary setting allows the system to automatically limit pressure at the design stage, eliminating the need for expensive high-pressure brake components while maintaining safety.
3Reliability
If a pre-loaded spring is used to limit pressure, then overpressure protection is improved, but device complexity increases
Solution Approach 1:
The spring mechanism is integrated directly into the valve assembly, with the spring positioned between the solenoid plunger and the valve spool. This merging of functions reduces the need for additional separate components and simplifies the overall structure.
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 effectively limits output pressure to a safe maximum, preventing overpressure and enhancing safety in the brake system while maintaining a compact design integrated into the electrohydraulic brake valve.
Implementation Method 1
When electrical power is supplied to the coil, which surrounds the armature, the coil generates an electromagnetic field through the armature. The plunger is driven by the electromagnetic field in the energized direction.
Implementation Method 2
The overpressure spring includes a spring force that is just above the force required for normal operation of the modulating valve. When the force from the solenoid assembly exceeds this spring force, the overpressure spring begins to compress.
Data Source
AI summary
An improved electrohydraulic brake valve with overpressure protection is provided. The electrohydraulic brake valve includes an integrated pressure limiting device coupled to a modulating valve and a solenoid assembly. The pressure limiting device transmits an axial force from the solenoid plunger to the valve spool up to a set limit, which corresponds to a maximum output pressure. Above this set limit, a pre-loaded spring within the pressure limiting device compresses, thereby isolating further travel of the solenoid plunger from the valve spool. The pressure limiting device mechanically limits the output pressure of the electrohydraulic brake valve to a maximum level to prevent overpressure in the brake system, adding a level of safety not previously available.