Valve Assembly with Pilot Pump and Pressure Compensator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing valve assemblies require expensive pressure sensors to ensure that the main volume flow from one working connection to another is controlled solely by the electric actuation signal, as the control volume flow depends on the pressure drop which is influenced by both the pilot valve position and pressure at the first working port.
Innovation Solution
Incorporating a positive displacement pump driven by an electric motor, which adjusts its drive speed via an electrical control signal, and a pressure compensator to maintain a constant pressure difference, allowing the main volume flow to be controlled independently of pressure sensors, using an external gear pump with a displacement volume between 0.5 cm³ and 10.0 cm³ per revolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure sensors are used to control the main volume flow solely by electric actuation signal, then the control precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent extracts the pressure sensing function from a separate pressure sensor and integrates it into the force balance mechanism of the valve piston. The valve piston naturally senses pressure differences through the forces acting on its end faces, eliminating the need for external pressure sensors while maintaining control precision.
Solution Approach 2:
The valve piston serves dual functions: it acts as both the control element and the pressure sensing element. By using the force balance on the valve piston to determine the control state, the system makes the component serve itself, removing the need for separate measurement devices and reducing overall system complexity.
2Manufacturing precision
If pressure sensors are used to compensate for pressure drop dependencies, then the volume flow control accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, precisely engineered pressure sensors with a simple force balance mechanism using the valve piston. This cheaper approach achieves comparable control accuracy by utilizing the natural physical forces on the valve piston rather than requiring costly sensing and compensation hardware.
Solution Approach 2:
The invention changes the control parameter from direct pressure measurement to force balance equilibrium. By controlling the valve piston position through electric actuation until forces balance, the system achieves accurate volume flow control without needing to measure or compensate for pressure drops using expensive sensors.
3Speed
If a variable throttle cross-section is used to create volume flow proportionality, then the control responsiveness is improved, but the sensitivity to pressure fluctuations increases
Solution Approach 1:
The valve piston position is determined by the balance of forces from pressure acting on its end faces. This creates a natural feedback mechanism where the valve automatically adjusts to equilibrium positions based on pressure conditions, stabilizing the control against pressure fluctuations while maintaining responsiveness through electric actuation.
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 configuration makes the valve assembly more cost-effective by eliminating the need for precise pressure sensors, as the main volume flow is controlled solely by the electric motor speed and current, with minimal dependency on pressure fluctuations, and allows for efficient operation with reduced leakage behavior.
Implementation Method 1
a positive displacement pump (50) driven by an electric motor (57) is provided, which can deliver hydraulic fluid from a first to a second fluid connection
Implementation Method 2
The positive displacement pump (50) is driven by an electric motor (57)
Implementation Method 3
The positive displacement pump (50) can be connected in series with a pressure compensator (55), which can adjust the pressure difference between the first and the second fluid connection (51; 52) to a predetermined value
Implementation Method 4
The positive displacement pump (50) is driven by an electric motor (57) which in turn is connected to a speed control device (20)
Data Source
Figure 1
Figure 2
AI summary
The valve assembly (10) comprises an adjustable throttle (37), which is provided between a housing (11) and a valve piston (30), where the throttle cross-section continuously varies with displacement of the valve piston. A working connection (12) is connected with a valve chamber (23) through the throttle. A displacement pump (50) is provided, which conveys the hydraulic fluid from a fluid connection (51) to another fluid connection (52). The former fluid connection is connected with the valve chamber. The displacement pump is driven by an electric motor (57). An independent claim is included for a valve arrangement with two valve assemblies and a tank non-return valve.