Pole Core Insert Bonding for Gas-Tight Damper Actuators

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Solution Overview

Problem

Prior art pole cores, used in electromagnetic actuators for vibration dampers, suffer from cohesive connection wear due to internal stresses and thermal expansion differences, leading to potential failure of the damper valve and vibration damper.

Innovation Solution

A manufacturing method for a pole core involving a magnetic workpiece with a groove, where non-magnetic inserts and a connecting means, such as copper, are inserted and melted to form a capillary connection, balancing material stresses and ensuring a cohesive, gas-tight seal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a non-magnetic insert is bonded to both the first and second sections by brazing, then the interruption is sealed gas-tight and liquid-tight, but the bonded connection is subject to wear due to residual stresses and different thermal expansion coefficients

Engineering Contradiction:
Improvetightness of interruptionVSAvoidservice life of bonded connection
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent changes the material parameters of the connecting means by selecting a material with specific properties: melting point between 900-1100°C, thermal expansion coefficient matched to the magnetic material (0.9-1.2×10^-6/K), and Young's modulus of 200-250 GPa. This parameter optimization ensures the connecting means can withstand thermal cycling and mechanical stresses without failing, resolving the contradiction between maintaining tightness and ensuring long-term durability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs a composite structure consisting of magnetic material sections (first and second sections) connected by a non-magnetic connecting means. This composite design allows each material to be optimized for its specific function: the magnetic materials provide magnetic flux conduction while the specially selected connecting means provides mechanical strength and thermal stability, preventing the wear and failure issues associated with conventional brazing connections.

Inventive Principle:
Principle #40Composite materials

2Reliability

If the outlet opening is closed more to increase throttling effect, then the damping behavior becomes harder, but the electromagnetic actuator must overcome higher forces

Engineering Contradiction:
Improvedamping control capabilityVSAvoidforce on electromagnetic actuator
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent applies local quality by creating a non-uniform magnetic field distribution through the specifically designed pole core geometry. The pole core concentrates magnetic flux at critical locations (such as the damper valve outlet opening) to maximize the electromagnetic force where it is most needed. This localized flux concentration allows the actuator to effectively control high-throttling positions without requiring proportionally higher overall actuator forces.

Inventive Principle:
Principle #3Local quality

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 method produces a long-term stable pole core with a balanced connection, reducing the risk of failure and maintaining tightness, thus enhancing the reliability of electromagnetic actuators and vibration dampers.

Implementation Method 1

when the bonding agent melts, capillary forces distribute the molten bonding agent over the contact surfaces between the workpiece and the inserts, completely wetting the contact surfaces, thereby creating an intermetallic bond

Methodology Applied
Scientific EffectCapillary action: Capillary Action

Implementation Method 2

materially connecting the at least two inserts to one another and/or the at least two inserts to the workpiece by preferentially melting the connecting means

Methodology Applied
Scientific EffectMelting: Melting

Implementation Method 3

due to its material properties, has a high level of elasticity, which allows tensions due to different thermal expansions of the inserts and the workpiece to be compensated

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 4

copper has a low viscosity in its molten state, which is why the melt of the connecting means completely wets the inserts in the groove due to capillary forces

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4115433B1Method for producing a pole core, pole core, electromagnetic actuator and vibration damper
Publication Date: 2024.09.11 KENDRION (VILLINGEN) GMBH
  • EP4115433B1 patent drawingFigure 1~2

AI summary

The present invention relates to a method for producing a pole core (1), comprising the following method steps: providing a magnetic workpiece (10), which has a first side (11) and a second side (12), the first side (11) having a groove (15) directed toward the second side (12); inserting at least two inserts (20) and at least one connecting means (25) into the groove (15), the at least one connecting means (25) being arranged between the two inserts (20); and integrally bonding the at least two inserts (20) to each other and/or the at least two inserts (20) to the workpiece (10).