Capacity Control Valve Spring-Biased Bellows for Stable Opening
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Solution Overview
Problem
Existing capacity control valves for variable displacement compressors can malfunction due to sudden increases in control pressure, leading to improper valve opening and potential excessive contraction of the bellows, which affects control fluid flow and precision.
Innovation Solution
A capacity control valve design that includes a pressure drive portion with a bellows core and a coil spring to bias the valve element in the closing direction, preventing malfunction even when control pressure increases, and ensuring stable operation by suppressing inflow to the pressure drive portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the control pressure Pc is applied to the valve element in the opening direction, then the valve element can be opened when needed, but the valve element may open unintentionally when control pressure increases due to outside vibration
Solution Approach 1:
The invention introduces a counter spring that applies a closing force to the valve element in opposition to the control pressure. This counter spring acts as a mechanical counterweight that balances the opening force from control pressure, preventing unintended valve opening while allowing controlled opening when the control pressure overcomes the spring force through the bellows mechanism
2Productivity
If the valve element opens due to high control pressure, then the valve responds to pressure changes, but control fluid flows into the suction chamber causing excessive bellows contraction
Solution Approach 1:
The invention introduces a counter spring as an intermediary element between the control pressure and the valve element. This intermediary absorbs and balances the control pressure through its elastic deformation, preventing direct transmission of excessive pressure to the bellows and suction chamber, thereby protecting the bellows from excessive contraction while still allowing controlled pressure response
3Device complexity
If a simple capacity control valve is used, then the device complexity is low, but the valve may malfunction under sudden pressure increases
Solution Approach 1:
The invention adds a counter spring that provides a closing force to balance the control pressure opening force. This simple mechanical counterweight mechanism prevents valve malfunction under sudden pressure increases without significantly complicating the overall valve structure, maintaining ease of manufacture while improving reliability
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 proposed solution enhances control precision by preventing unintended valve opening and maintaining stable valve states, even under conditions of increased control pressure, thus ensuring reliable operation of variable displacement compressors.
Implementation Method 1
a coil spring which is housed inside the bellows core and is configured to bias the bellows core at all times in a direction in which the bellows core is extended
Implementation Method 2
that receives a force in a contracting direction from the suction fluid, the contracting direction being a direction in which the pressure drive portion is contractable
Implementation Method 3
the valve element receives a force in a valve opening direction of the main valve from the pressure drive portion
Data Source
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AI summary
A capacity control valve in which control precision is high is provided. A capacity control valve V includes a valve housing 10 provided with a suction port 13 through which a suction fluid of suction pressure Ps passes, and a control port 15 through which a control fluid of control pressure Pc passes, a pressure drive portion 61 that receives a force in the contracting direction from the suction fluid, and a main valve 50 formed by a valve element 51 that receives a force in the valve opening direction from the pressure drive portion 61, and a valve seat 53 with and from which the valve element 51 is brought into contact and separated. The valve element 51 is arranged to receive a force in the closing direction from the control fluid.