Electric Valve Constricted Surface for Low-Flow Control
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Solution Overview
Problem
Conventional electric valves face challenges in managing rising flow rates and controllability in low flow ranges, particularly with the use of R32 refrigerant and increased partial load operations, due to complex dimensional measurements and potential corner generation during machining, leading to insufficient flow rate reduction and resolution issues.
Innovation Solution
The electric valve design incorporates a constricted surface portion with a smaller outer diameter between the seating and curved surface portions, along with a straight portion of constant diameter, to suppress corner generation and maintain a larger outer diameter for the curved surface, thereby reducing rising flow rates and improving controllability in low flow ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If a straight portion with constant outer diameter is provided between the seating surface portion and the curved surface portion, then dimensional measurement is simplified, but a region with no flow rate change is generated causing decline in resolution
Solution Approach 1:
The constricted surface portion creates a localized change in outer diameter between the seating surface portion and the curved surface portion. This local geometric feature provides a measurable reference point while maintaining the necessary flow rate characteristics, thus simplifying dimensional measurement without creating a region with no flow rate change.
2Object-generated harmful factors
If the outer diameter of the curved surface portion is reduced to avoid corner R seating, then rising flow rate reduction is achieved, but manufacturing complexity increases
Solution Approach 1:
The valve body surface is segmented into distinct portions: the seating surface portion, the constricted surface portion, and the curved surface portion. This segmentation allows each portion to have optimized dimensions independent of the others, enabling the curved surface portion to maintain a larger outer diameter for easier manufacturing while the constricted surface portion controls the rising flow rate characteristic.
3Ease of manufacture
If the outer diameter of the curved surface portion is maintained large, then manufacturing is simplified, but corner R generation occurs causing seating issues
Solution Approach 1:
The constricted surface portion is extracted as a separate geometric feature between the seating surface portion and the curved surface portion. This extracted feature serves to eliminate corner R generation at the intersection, allowing the curved surface portion to maintain a large outer diameter for manufacturing simplicity while the constricted surface portion ensures proper seating performance by preventing corner R issues.
Data Source
AI summary
An electric valve includes a seating surface portion attached to a valve seat and a curved surface portion inserted into a valve port that are disposed in a valve body. A constricted surface portion smaller in outer diameter than an upper end portion of the curved surface portion is provided between the seating surface portion and the curved surface portion. As a result, a rising flow rate can be sufficiently reduced and controllability in a low flow range can be effectively improved with management of the rising flow rate simplified.