Electromagnetic Actuating Unit Bearing Alignment

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Solution Overview

Problem

Existing electromagnetic control units for hydraulic directional valves in internal combustion engines suffer from increased wear and reduced functionality due to eccentricity of the magnet armature, caused by misalignment between armature and pole core bearings, leading to lateral forces and progressive wear, which affects the precise adjustment of control times.

Innovation Solution

The electromagnetic control unit features a central magnet with an armature unit supported by two bearing points, where at least one bearing point is 'floating' during assembly, allowing for coaxial alignment and subsequent fixation, ensuring axial displacement and reducing lateral forces through a centering sleeve or assembly device, and a compact design with rotationally symmetrical components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the armature and pole core are mounted using fixed bearing points with standard tolerances, then the manufacturing cost is reduced and assembly is simplified, but misalignment occurs leading to eccentricity and increased wear

Engineering Contradiction:
Improvemanufacturing costVSAvoidservice life
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent makes one bearing point (the pole core bearing) dynamically adjustable during assembly rather than fixed. The pole core can be positioned and adjusted to achieve perfect coaxiality with the armature bearing, then fixed in the correct position. This dynamic adjustment process resolves the contradiction by allowing cost-effective standard tolerances in manufacturing while ensuring precise alignment through the adjustment step, thereby preventing eccentricity and extending service life.

Inventive Principle:
Principle #15Dynamics

2Reliability

If tight tolerances are used for bearing point alignment, then concentricity and service life are improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveservice lifeVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a preliminary alignment action using a centering sleeve or assembly device before final fixation. The centering sleeve is temporarily inserted to guide and align the pole core and armature coaxially during assembly. This preliminary alignment action ensures perfect concentricity without requiring tight manufacturing tolerances, as the alignment is achieved through the centering aid rather than precision machining. After alignment, the pole core is fixed in position, leaving the assembly with both high reliability and ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

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 enhances the concentricity of bearing points, reduces wear, and extends the service life of the control unit while allowing for cost-effective production and precise adjustment of control times in internal combustion engines.

Implementation Method 1

an armature, which is arranged in an axially displaceable manner within an armature space, and a pole core, which is arranged in a receptacle and delimits the armature space in a direction of movement of the armature. The electromagnetic actuator includes a coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The bearing points are aligned using a centering sleeve (19) which is introduced into the coil (01) as a centering aid

Methodology Applied
Scientific EffectMechanical alignment:

Data Source

PatentEP2370675B1Electromagnetic actuating unit for a hydraulic directional control valve and method for the assembly thereof
Publication Date: 2014.12.10 SCHAEFFLER TECHNOLOGIES AG & CO KG
  • EP2370675B1 patent drawingFigure 1
  • EP2370675B1 patent drawingFigure 2~5
  • EP2370675B1 patent drawingFigure 6~8b

AI summary

The invention relates to an electromagnetic actuating unit for a hydraulic directional control valve and to a method for the assembly thereof. The actuating unit comprises a coil (01) for generating a magnetic field; a yoke unit having a yoke (04) and a yoke plate (06, 31), and a pole core unit having a pole core (07) and a housing (08) for conducting a magnetic flux; and an armature unit which is arranged in the magnetic field of the coil (01) and has an armature (09) and a pressure pin (11) as an actuator. The armature unit can be displaced in the direction of the longitudinal axis thereof in a first bearing point (16) in the yoke unit and in a second bearing point (17) in the pole core unit. According to the invention, at least one of the bearing points (16, 17) can be displaced in the radial direction during assembly of the actuating unit and can be fixed after a coaxial orientation of both bearing points.