Valve Assembly With Preloaded Oil Return for Stable Position Control
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Solution Overview
Problem
Existing valve assemblies in vehicles require separate pressure regulating devices for different hydraulic consumers, leading to inefficiencies and increased costs due to varying supply pressures needed for proper function.
Innovation Solution
Incorporating a check valve connected to the control oil return via a preloaded spring, which utilizes existing leakages to maintain a defined opening pressure, allowing the valve assembly to function optimally across different pressure levels by ensuring only the pressure difference affects the position control, and using a common check valve for multiple valve disks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate pressure regulating devices are used for different hydraulic consumers, then each consumer receives the required supply pressure, but the device complexity and cost increase
Solution Approach 1:
The patent combines multiple pressure regulating functions into a single valve assembly. The main slider valve integrates control for multiple hydraulic consumers, allowing different supply pressures to be achieved through a unified structure rather than separate pressure regulating devices for each consumer.
Solution Approach 2:
The valve assembly is designed with multi-functionality to serve multiple hydraulic consumers simultaneously. The main slider can position multiple spool valves that control different hydraulic circuits, enabling one device to perform what previously required multiple separate pressure regulating devices.
2Adaptability or versatility
If a check valve with preloaded spring is used to maintain opening pressure, then the valve assembly can operate at higher supply pressures, but the construction becomes more complex
Solution Approach 1:
The check valve with preloaded spring automatically maintains the opening pressure in the control oil return without requiring external control mechanisms. The spring preload creates a predetermined opening pressure that self-regulates the system, eliminating the need for complex active pressure control systems.
Solution Approach 2:
The patent converts the leakage flow, which was previously considered a harmful effect, into a beneficial function. The leakage flow through the pilot valve is used to keep the check valve open, ensuring the opening pressure is maintained even when the pilot valve is in the zero position where theoretically no volumetric flow should occur.
3Reliability
If leakage flows are utilized to keep the check valve open, then the opening pressure is maintained at zero position, but the position control precision may be affected
Solution Approach 1:
The patent extracts and separates the pressure maintenance function from the position control function. The check valve with preloaded spring handles pressure maintenance independently, while the pilot valve handles position control. This separation allows the leakage flow to be used for pressure maintenance without significantly affecting position control precision.
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 operation at higher supply pressures with simplified construction, reducing the need for separate pressure reduction valves and allowing adaptation to varying hydraulic consumer pressures, ensuring optimal position control regardless of inlet pressure levels.
Implementation Method 1
the check valve is preloaded to a closed position by means of a first spring
Implementation Method 2
the check valve only permits fluid flow from the pilot valve toward the control oil return
Implementation Method 3
the leakages at the pilot valve from the control oil inlet toward the check valve are designed to be so large that if the pressure at the control oil inlet exceeds the opening pressure by at least 2 bar, the opening pressure of the check valve is present immediately upstream of the check valve
Data Source
AI summary
A valve assembly includes a linearly moving main slider, a pilot valve, a control oil inlet, and a control oil return. The pilot valve is designed as a 4/3 proportional directional valve, via which a first end face and an opposite second end face of the main slider can be fluidly connected selectively to the control oil inlet or the control oil return so that the main slider (20) is hydraulically movable by adjusting the pilot valve. The pilot valve is electrically adjustable depending on a target current. A position sensor is provided, with which an actual position of the main slider can be measured. A positioner is provided, with which the actual position can be regulated by adjusting the target current to a predefinable target position. The pilot valve is connected to the control oil return via a check valve. The check valve only permits fluid flow from the pilot valve toward the control oil return. The check valve is preloaded to a closed position by means of a first spring so that it opens at a predetermined opening pressure. The leakages at the pilot valve from the control oil inlet toward the check valve are designed to be so large that if the pressure at the control oil inlet exceeds the opening pressure by at least 2 bar, the opening pressure of the check valve is present immediately upstream of the check valve.