Capacity Control Valve with Austenitic Stainless Steel Bellows
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Solution Overview
Problem
Existing capacity control valves for variable-capacity compressors, such as those used in automobile air-conditioning systems, face challenges in achieving size reduction and weight reduction due to the limitations of phosphor bronze bellows, which require increased diameter and thickness to ensure long stroke, leading to poor formability and increased diameter of the valve element and valve body.
Innovation Solution
The capacity control valve features a formed bellows made of material with higher yield stress than phosphor bronze, eliminating internal springs and using austenitic stainless material, with a hollow cylindrical adapter and partition adjustment member formed from non-magnetic materials, fixed by electron beam welding to maintain an absolute vacuum state, allowing for reduced diameter and improved stroke, resulting in a lighter, more space-saving design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If phosphor bronze bellows are used with increased diameter and thickness to ensure long stroke, then the stroke reliability is improved, but the valve diameter and weight increase
Solution Approach 1:
The patent changes the material parameter from phosphor bronze to austenitic stainless steel, which has superior mechanical properties including higher elastic limit and fatigue strength. This material substitution allows the bellows to achieve the required stroke duration with reduced diameter and thickness, directly resolving the contradiction between stroke reliability and weight.
Solution Approach 2:
The patent employs austenitic stainless steel as a composite material solution that combines multiple desirable properties: high elasticity, corrosion resistance, and structural strength. This composite material approach enables the bellows to maintain long stroke capability while significantly reducing the overall valve diameter and weight compared to traditional phosphor bronze constructions.
2Duration of action of moving object
If phosphor bronze bellows are used with increased diameter and thickness to ensure long stroke, then the stroke reliability is improved, but the manufacturing complexity increases
Solution Approach 1:
By changing the material parameter to austenitic stainless steel, the patent improves formability during manufacturing. The austenitic structure provides excellent plastic deformability, allowing the bellows to be formed into complex shapes with smaller diameters and thinner walls while maintaining the required stroke length, thus resolving the manufacturing complexity issue.
Solution Approach 2:
The patent applies local quality optimization by using austenitic stainless steel specifically for the bellows component where high formability and structural integrity are simultaneously required. This localized material selection enables precise control over the bellows geometry and stroke characteristics without compromising manufacturing ease.
3Reliability
If internal springs are included in the bellows to generate bias force, then the valve control reliability is improved, but the device complexity and weight increase
Solution Approach 1:
The patent extracts and eliminates the internal spring component from the bellows structure. Instead of using a separate spring mechanism, the bias force is generated directly by the elastic deformation capability of the austenitic stainless steel bellows material itself. This extraction simplifies the internal structure, reduces weight, and maintains valve control reliability.
Solution Approach 2:
The austenitic stainless steel bellows serves multiple functions simultaneously: it provides the structural housing, generates the bias force through its elastic properties, and maintains the vacuum seal. This multi-functionality eliminates the need for separate internal springs, thereby reducing device complexity while preserving control reliability.
4Weight of stationary object
If the bellows diameter is reduced to achieve size reduction, then the valve body diameter is reduced, but the stroke length may be compromised
Solution Approach 1:
The patent changes the material parameters of the bellows to austenitic stainless steel, which has superior elastic properties and higher allowable stress. This enables the bellows to achieve the required stroke length even with a reduced diameter, as the material can sustain greater elastic deformation within a compact geometry, thus resolving the contradiction between size reduction and stroke maintenance.
Solution Approach 2:
The patent performs preliminary material selection and structural optimization to ensure that the reduced-diameter bellows can still achieve the required stroke length. By pre-calculating and pre-designing the wall thickness and expansion ratio based on austenitic stainless steel properties, the bellows is configured to maintain adequate stroke capability despite the smaller overall diameter.
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 reduces the diameter and weight of the valve body, enhances vibration resistance, and improves durability by allowing a longer stroke with a smaller diameter, contributing to size and weight reduction of the compressor and vehicle, while also improving manufacturing ease and sensing accuracy.
Implementation Method 1
a pressure-sensitive body positioned in the third valve chamber to apply, by extending, a bias force in the direction of opening the first valve part, and also to contract as the surrounding pressure increases
Implementation Method 2
a solenoid that applies an electromagnetic drive force to the valve element in the direction of closing the first valve part
Implementation Method 3
the formed bellows, adapter, and partition adjustment member are fixed by electron beam welding
Data Source
Figure 1
Figure 2
Figure 3(a)~3(b)
AI summary
{Technical Problem} Provided is a capacity control valve that has no internal spring positioned in the bellows of the pressure-sensitive unit and also reduces the diameter of the valve element and that of the bellows to achieve size reduction and weight reduction. {Solution to Problem} The capacity control valve comprises: a pressure-sensitive body 50 positioned in the third valve chamber 38 to apply a bias force, by extending, in the direction of opening the first valve part 41, and also to contract as the surrounding pressure increases; an adapter 53 provided on the free end of the pressure-sensitive body in the extending/contracting directions and having a circular seating surface; a third valve part 43 that moves integrally with the valve element 40 in the third valve chamber 38 and has a circular engagement surface that opens/closes the intake-side passages 34 by engaging with and separating from the seating surface of the adapter; and a solenoid 60 that applies an electromagnetic drive force to the valve element 40 in the direction of closing the first valve part 41; wherein such capacity control valve is characterized in that: the pressure-sensitive body 50 is formed by a formed bellows made of material having greater yield stress than phosphor bronze; and the formed bellows has its diameter set smaller and its stroke longer than the diameter and stroke of a phosphor bronze bellows.