Metering Magnet Coupling Element for Dosing Accuracy

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing dosing magnets used in vending machines for adding concentrates to water suffer from low dosing accuracy due to mechanical reworking requirements and tolerance issues in the non-magnetic section, leading to a high reject rate.

Innovation Solution

A dosing magnet design featuring a coupling element with axially spaced magnetically conductive bushings, where the bushings are fixed on a non-magnetic sleeve, allowing precise adjustment of the air gap and inductance, eliminating the need for mechanical reworking and adhesive, and ensuring consistent dosing accuracy across batches.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If mechanical reworking is performed on the armature hole face to ensure exact position of the dosing pump, then positioning accuracy is improved, but manufacturing complexity and production time increase

Engineering Contradiction:
Improvearmature position accuracyVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The coupling element is designed with integrated positioning features (such as shoulders, recesses, or geometric constraints) that pre-establish the exact position of the dosing pump and armature before final assembly. This preliminary geometric definition eliminates the need for post-assembly mechanical reworking of the armature hole face, as the positioning is achieved during the coupling element manufacturing itself through precision machining or molding of its geometric features.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the non-magnetic section length is adjusted to achieve exact dosing pump position, then dosing accuracy is improved, but the ability to adjust armature position is lost

Engineering Contradiction:
Improvedosing pump position accuracyVSAvoidarmature position adjustability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The coupling element is designed as a separate, modular component that mediates between the armature and the dosing pump. This segmentation allows the non-magnetic section length to be optimized for dosing pump positioning while the coupling element itself provides the adjustment mechanism for armature position through features such as adjustable bushings, movable components, or geometric tolerance zones. The coupling element thus decouples the two positioning functions, enabling both precision and adjustability.

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If adhesive is used to secure the cover with the housing pot, then assembly ease is improved, but dosing accuracy is reduced due to tolerance accumulation

Engineering Contradiction:
Improveassembly easeVSAvoiddosing accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The coupling element is designed with mechanical positioning and securing features (such as interference fits, threaded connections, snap-fits, or geometric locking mechanisms) that replace the adhesive bonding method. This mechanical system provides precise, repeatable positioning of the cover relative to the housing pot without the tolerance accumulation associated with adhesive layers. The mechanical features enable accurate dosing while maintaining ease of assembly through standardized mechanical joining methods.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Ease of manufacture

If a plastic ring is used as the non-magnetic section, then ease of manufacture is improved, but dosing accuracy is reduced due to elasticity and tolerance chain

Engineering Contradiction:
Improvenon-magnetic section manufacturing easeVSAvoiddosing accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The coupling element is designed with controlled material properties and geometric parameters that eliminate the elasticity problem of plastic rings. This may involve using rigid non-magnetic materials (such as non-magnetic metals or rigid plastics), optimizing wall thickness to minimize elastic deformation, incorporating reinforcing ribs or structural features, or designing the geometry to compensate for thermal expansion and manufacturing tolerances. The result is a non-magnetic section that maintains dimensional stability and precise positioning without the tolerance accumulation caused by elastic plastic rings.

Inventive Principle:
Principle #35Parameter changes

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 solution significantly reduces the tolerance chain during production, achieving high dosing accuracy and reducing the reject rate by precisely setting the non-magnetic section length and maintaining it permanently, thus ensuring a constant dosing quantity.

Implementation Method 1

having an exciter coil (3) with an armature bore (5) and a metering pump (6) arranged in the armature bore (5) with an armature (7)

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

two axially connected through a non-magnetic section in the armature bore spaced-apart magnetically conductive bushings (8, 9) are arranged

Methodology Applied
Scientific EffectMagnetic conduction: Magnetism

Data Source

PatentEP2132754B1Metering magnet
Publication Date: 2018.11.07 JOHNSON ELECTRIC GERMANY GMBH & CO KG
  • EP2132754B1 patent drawingFigure 1~2
  • EP2132754B1 patent drawingFigure 3~4
  • EP2132754B1 patent drawingFigure 5

AI summary

The invention relates to a metering magnet (1), which comprises at least one main body (4) placed in a housing (2) and having an exciter coil (3), and further comprises an armature bore (5) and a metering pump (6) disposed in the armature bore (5), said metering pump having an armature (7) operating in the direction of the longitudinal axis of the armature bore (5). Two magnetically conductive bushings (8, 9) are disposed in the armature bore (5), said conductive bushings being axially spaced from one another by a non-magnetic section (10). In addition, a coupling element (11) is provided in the armature bore (5), on or in said coupling element the two bushings (8, 9) located axially at a distance from one another being disposed in a fixed manner and oriented toward one another by means of the geometrically defined non-magnetic section (10).