Flow Control Valve Throttle Geometry for Fluid Force Balancing
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Solution Overview
Problem
Existing flow control valves in hydraulic circuits of construction machines suffer from deteriorated displacement characteristics due to fluid forces, making it difficult to control the opening amount of the main valve throttle and fluid forces effectively, while also requiring larger parts that increase manufacturing costs.
Innovation Solution
The main valve throttle is configured with a lateral hole and a groove portion, allowing the jet flow direction to align parallel to the center axis, reducing fluid forces and enabling independent control of the opening amount, without increasing the pressure receiving diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the main valve throttle is configured with a lateral hole, then the opening amount can be controlled, but fluid forces act on the main valve in the valve opening direction which deteriorates displacement characteristics
Solution Approach 1:
The patent introduces a groove portion that generates a counteracting fluid force to cancel the harmful fluid force from the lateral hole. The groove portion allows hydraulic fluid to flow and generate a force in the valve closing direction that opposes the fluid force from the lateral hole, thereby converting the harmful fluid force into a balanced system where the net fluid force is reduced or eliminated.
Solution Approach 2:
The patent modifies the throttle configuration by adding the groove portion with specific geometric parameters (depth, width, position) to change the fluid flow characteristics. By adjusting the parameters of the groove portion, the fluid force generated can be optimized to counterbalance the harmful fluid force while maintaining the desired opening amount control.
2Object-generated harmful factors
If the pressure receiving diameter is increased to reduce fluid forces, then fluid forces are reduced, but the valve size increases which increases manufacturing costs
Solution Approach 1:
Instead of increasing the overall valve size, the patent applies the groove portion locally at the throttle region where the fluid force problem occurs. This localized modification allows the generation of counteracting fluid force without increasing the pressure receiving diameter or the overall valve dimensions, thereby reducing fluid forces while maintaining a compact valve size.
3Ease of operation
If the main valve is displaced in the valve closing direction to reduce opening amount, then the opening amount decreases, but the jet flow direction changes causing rapid displacement which deteriorates displacement characteristics
Solution Approach 1:
The groove portion generates a stabilizing fluid force that counteracts the change in jet flow direction during valve displacement. As the main valve moves and the jet flow direction changes, the groove portion continues to provide a counteracting force that opposes the harmful fluid force, thereby stabilizing the displacement characteristics and preventing rapid displacement.
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 improves displacement characteristics by reducing fluid forces, allowing for precise control of the opening amount and fluid forces, while maintaining a smaller valve size, suitable for conventional products with minimal modifications.
Implementation Method 1
a groove portion (53C) communicating the inlet side flow passage (25) with the outlet side flow passage (27) via an outer peripheral portion of the main valve (43). In this case, the direction of a jet flow passing through the main valve throttle (53) can approach the direction parallel to the center axis of the main valve (43)
Data Source
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AI summary
A main valve throttle (53) of a main valve (43) is configured by a lateral hole (53A) communicating an inlet side flow passage (25) and an outlet side flow passage (27) through the inside of the main valve (43) and a groove portion (53C) communicating the inlet side flow passage (25) and the outlet side flow passage (27) via an outer peripheral portion of the main valve (43). The groove portion (53C) is located such that a hydraulic fluid spurting from the groove portion (53C) changes the direction of a flow of a hydraulic fluid spurting from the lateral hole (53A) . In this case, the direction of a flow of a hydraulic fluid F2 spurting from the lateral hole (53A) can be changed to approach the direction parallel to the center axis of the main valve (43) by a hydraulic fluid F1 spurting from the groove portion (53C).