Integrated Valve Needle and Spring for Expansion Valve Cost Reduction
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Solution Overview
Problem
Existing electric expansion valves in air-conditioning systems of motor vehicles have complex and expensive designs due to their elaborate structure, which increases assembly, storage, and logistical costs.
Innovation Solution
The development of a valve body with an integral valve needle and spring, which simplifies the design and reduces the number of parts, allowing for a more cost-effective and easier assembly process. The spring is designed with meander-shaped arms for adjustable spring force and a support ring for low contact pressure with the permanent magnet body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the valve body is designed with separate valve needle and spring components, then assembly and maintenance are more flexible, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the valve needle and spring into a single integrated valve body component manufactured as one piece using injection molding. This merging eliminates the need for separate assembly of these parts, reducing the total number of components while lowering manufacturing costs through a single production process.
Solution Approach 2:
The integrated valve body serves multiple functions simultaneously: it acts as the structural housing, contains the valve needle for flow control, incorporates the spring for return force, and includes the support ring for positioning. This multi-functionality reduces the number of separate parts needed in the expansion valve assembly.
2Productivity
If the valve needle and spring are assembled separately, then replacement and maintenance are easier, but assembly costs and tolerance accumulation increase
Solution Approach 1:
By integrating the valve needle and spring into a single molded component, the patent eliminates the assembly step between these parts, thereby eliminating the tolerance chain that would accumulate from separate manufacturing and assembly operations. This single-piece construction ensures consistent positioning and reduces assembly costs.
3Reliability
If a traditional coil spring is used, then the spring force is reliable, but the contact pressure with the permanent magnet body is too high causing twisting
Solution Approach 1:
The patent replaces the traditional coil spring with a flexible membrane spring formed as an integrated part of the valve body. This membrane structure provides the necessary spring force while distributing the contact pressure over a larger area, preventing excessive localized pressure on the permanent magnet body and eliminating the twisting problem.
Solution Approach 2:
The patent changes the physical form and material properties of the spring element from a metal coil spring to an elastomeric membrane structure. This parameter change in material and geometry allows the spring to provide reliable force while reducing contact pressure through increased surface area distribution.
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 solution reduces assembly, storage, and logistical costs by simplifying the design and reducing the number of parts, while also ensuring reliable refrigerant flow and maintaining a stable spring force around a predefined operating point.
Implementation Method 1
the spring comprises two meander-shaped arms which at the one end are integrally connected to the valve needle and on the other hand to a support ring
Implementation Method 2
the refrigerant, which usually enters the expansion valve as almost boiling liquid. In the process, it is subjected to an isenthalpic change of state, since the refrigerant on passing through the expansion valve expands (pressure drop from for example 10 bar to 1 bar with simultaneous drop of the liquid temperature)
Implementation Method 3
the refrigerant enters the evaporator, in which the evaporation process of the liquid fraction of the refrigerant absorbs heat from the surroundings and thereby evaporates. The fluid or air flowing through the evaporator (heat exchanger) is cooled in the process.
Data Source
AI summary
A valve body of an expansion valve for an air-conditioning system, a battery cooler, and/or an oil cooler of a motor vehicle may comprise a valve needle and a spring. The valve needle and the spring may be integrally provided as a single component.