Stepped Control Piston Geometry for Hydraulic Flow Force Compensation
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Solution Overview
Problem
Existing proportional pressure control valves face inefficiencies in flow force compensation on the control piston, leading to undesirable pressure drops and disruptions in fluid flow, which affect the accuracy and stability of hydraulic systems.
Innovation Solution
The control piston is designed with a hollow end and a step function shape change, dividing the flow attack surface into multiple concentric annular surfaces, creating a fluid space that generates a counterforce to counteract flow forces, optimizing force transmission and fluid flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a simple flow control valve is used, then the device complexity is low, but flow forces act on the closing element causing premature wear and positioning inaccuracy
Solution Approach 1:
The patent introduces a counterbalancing piston that generates a counter force opposing the flow force acting on the closing element. This counter force compensates for the harmful flow forces, allowing the valve to maintain positioning accuracy without requiring an overly complex structure. The counterbalancing mechanism directly addresses the contradiction by neutralizing the problematic flow forces while keeping the overall device complexity manageable.
Solution Approach 2:
The patent employs an intermediary fluid connection between the control chamber and the counterbalancing piston. This intermediary fluid pathway transmits pressure forces to generate the counterbalancing force, allowing the system to achieve precise positioning without direct mechanical complexity. The fluid intermediary enables force transmission while maintaining a relatively simple structural design.
2Reliability
If flow forces are compensated, then the reliability and service life improve, but the device complexity increases due to additional components
Solution Approach 1:
The counterbalancing piston generates a counter force that directly opposes the flow force, preventing premature wear of the closing element. This approach improves reliability and service life by eliminating the harmful effects of unbalanced flow forces, while the piston-based mechanism maintains reasonable structural complexity rather than requiring multiple separate compensation systems.
Solution Approach 2:
The patent merges the flow control function with the force balancing function into a single integrated valve structure. The closing element simultaneously performs flow regulation and experiences force balancing through the connected counterbalancing piston, reducing the need for separate compensation mechanisms and thereby limiting the increase in device complexity while improving reliability.
3Ease of manufacture
If a simple valve structure is used, then the ease of manufacture is high, but wear on the closing element increases due to unbalanced flow forces
Solution Approach 1:
The counterbalancing piston generates a counter force that balances the flow force acting on the closing element, significantly reducing wear. This approach maintains manufacturing simplicity by using a straightforward piston and fluid connection design, rather than requiring complex wear-resistant materials or intricate cooling systems. The force balancing directly addresses the wear issue while keeping manufacturing relatively simple.
Solution Approach 2:
The valve system uses the fluid pressure itself to generate the counterbalancing force through the piston mechanism. The same fluid that drives the flow control also provides the counter force needed to reduce wear, allowing the system to protect itself without requiring external intervention or complex additional components. This self-service approach improves wear resistance while maintaining manufacturing simplicity.
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 design effectively compensates for flow forces, maintaining consistent pressure supply to hydraulic consumers by minimizing disruptive fluid movements and ensuring precise control.
Implementation Method 1
counterbalancing piston (42) arranged to compensate for the flow forces by generating a counter force
Implementation Method 2
valve body (10) with a flow channel (13) running through the valve body (10) in a direction transverse to the closing element (20)
Data Source
Figure 1a~1b
Figure 2a~2c
Figure 3a~3c
AI summary
The invention relates to a device consisting of at least one control piston (12) which is longitudinally displaceable in a housing (10), said housing comprising at least two connection points (A, P, T) for fluid, and which cooperates with a control edge (56), which follows a step function, of the housing (10) at a pressure supply connection point (P) which supplies another connection point (A), serving as a utility connection, with fluid via a fluid connection and with a predefinable pressure in control positions of the control piston (12) and seeks to pull the same as a result of occurring flow forces in the direction of a closing position blocking this fluid connection. According to the invention and in order to compensate the flow force, the control piston (12) has in the region of the control edge (56) of the housing (10) a shape modification (60) of its exterior basic form (50) such that a flow contact surface for fluid is created, which causes a compensating force that acts against the flow force and onto the control piston (12), said compensating force seeking to pull the control piston (12) into an opening position opposed to the closing position, wherein the shape modification (60) also follows a step function, the functional graph of which has at least one more step than the required number of steps for forming the control edge (56).