Capacity Control Valve Magnetic Core Taper for Smooth Stroke Holding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing capacity control valves face challenges in smoothly controlling the valve element and stably holding it at the maximum stroke position due to issues with magnetic force distribution and size, requiring either a large structure or insufficient axial thrust force.

Innovation Solution

The capacity control valve features a design with projected portions on the iron cores formed in a tapered shape, allowing for a radial component of magnetic force to be minimized initially while ensuring a rapid increase in axial thrust force near the maximum stroke position, using a normal open type configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If both iron cores are formed with flat surfaces orthogonal to the axial direction, then the structure is simple, but magnetic force rapidly increases when iron cores are brought close, making fine adjustment difficult

Engineering Contradiction:
Improvestructural simplicityVSAvoidfine adjustment capability
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent applies different surface geometries to different regions of the iron cores. The movable iron core has a flat opposing surface for stable holding, while the fixed iron core has a tapered projected portion that provides gradual magnetic force increase during approach, enabling fine adjustment. This local differentiation resolves the contradiction between structural simplicity and fine adjustment capability.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If one iron core has a circular-conical opposing surface and the other has a complementary recessed shape, then fine adjustment is enabled, but axial thrust force becomes small requiring a large solenoid

Engineering Contradiction:
Improvefine adjustment capabilityVSAvoidaxial thrust force
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The patent segments the magnetic interaction surface into two functional zones: a tapered projected portion for fine adjustment during approach, and a flat opposing surface for generating strong axial thrust force when closed. This segmentation allows each zone to optimize its function without compromising the other, resolving the contradiction between fine adjustment and thrust force.

Inventive Principle:
Principle #1Segmentation

3Force

If the separation distance between iron cores at maximum stroke position is small, then axial thrust force increases, but fine adjustment of opening and closing becomes difficult

Engineering Contradiction:
Improveaxial thrust forceVSAvoidfine adjustment capability
Core Design Contradiction:
ForceVSEase of operation

Solution Approach 1:

The patent introduces a radial dimension to the magnetic interaction through the tapered projected portion. During approach, the radial taper provides gradual magnetic force increase for fine adjustment. When closed, the flat opposing surface ensures small separation distance for strong axial thrust force. This dimensional approach resolves the contradiction between thrust force and fine adjustment.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 design enables smooth control of the valve element and stable holding at the maximum stroke position with a large axial thrust force, maintaining a closed state under pressure, thus enhancing the operational efficiency and reliability of the valve.

Implementation Method 1

the position of the valve element is changed by drawing the movable iron core to the fixed iron core with magnetic force generated in accordance with energization of the electromagnetic coil

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3951169B1Capacity control valve
Publication Date: 2026.02.18 EAGLE INDS
  • EP3951169B1 patent drawingFigure 1
  • EP3951169B1 patent drawingFigure 2
  • EP3951169B1 patent drawingFigure 3

AI summary

A capacity control valve with which a valve element can be smoothly controlled and the valve element can be stably held at a maximum stroke position is provided. In a capacity control valve V, a position of a valve element 51 is changed by drawing a movable iron core 84 to a fixed iron core 82 with magnetic force by energization of an electromagnetic coil 86. The iron core 82 on one side includes a projected portion 90 on the radially outer side, the iron core 84 on the other side includes a projected portion 92 on the radially inner side, and these projected portions are capable of being loosely fitted to each other when the movable iron core 84 is drawn to the fixed iron core 82. The projected portion 90 is formed to be smaller than an opposing surface 93 of the iron core 84 facing an effective magnetic force surface 90a of a distal end of the projected portion and formed in a tapered shape.