Variable Effort Steering Actuator With Symmetric Pole Teeth

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Solution Overview

Problem

Current magnetic actuators for power steering systems are larger in size and more difficult to manufacture due to inefficient magnet utilization and complex tooth designs, making them costly and challenging to produce.

Innovation Solution

A compact magnetic actuator design featuring symmetrically arranged inner and outer pole teeth of varying widths, with optional grooves, and a magnetic ring composed of permanent magnets, optimized for efficient torque delivery and simplified manufacturing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If teeth in magnetic actuators are arranged in groups with different profiles, mis-aligned inner and outer teeth, and asymmetrical arrangement, then desired torque can be achieved, but manufacturing becomes difficult and expensive

Engineering Contradiction:
ImprovetorqueVSAvoidmanufacturing complexity
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The patent applies asymmetry in reverse by using symmetrical arrangements. The inner pole teeth and outer pole teeth are arranged symmetrically with respect to the magnetic ring, creating identical or mirror-image patterns on both sides. This symmetrical design simplifies manufacturing while maintaining the required torque characteristics through balanced magnetic field distribution.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The magnetic actuator is segmented into distinct components: inner pole teeth, outer pole teeth, and magnetic ring segments. Each segment can be manufactured separately using standardized processes, then assembled together. This segmentation allows for simpler individual component manufacturing while achieving the desired complex torque characteristics through the combination of segments.

Inventive Principle:
Principle #1Segmentation

2Force

If complex tooth arrangements are used to achieve desired torque, then torque specifications are met, but magnet utilization becomes inefficient and size increases

Engineering Contradiction:
ImprovetorqueVSAvoidactuator size
Core Design Contradiction:
ForceVSVolume of moving object

Solution Approach 1:

The patent optimizes torque output by changing geometric parameters of the pole teeth, such as tooth width, tooth pitch, and pole arc ratios. By carefully selecting these parameters, the design achieves desired torque characteristics with more efficient magnet utilization, reducing the overall actuator size while meeting performance specifications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Different regions of the magnetic actuator are designed with locally optimized characteristics. The inner and outer pole teeth have specific width variations and positioning that create localized magnetic field enhancements, allowing efficient torque generation in specific areas without requiring the entire actuator to be oversized.

Inventive Principle:
Principle #3Local quality

3Force

If inner and outer teeth are mis-aligned and profiled differently, then torque characteristics are achieved, but manufacturing precision requirements increase

Engineering Contradiction:
ImprovetorqueVSAvoidtooth alignment precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The patent uses symmetrical arrangements of inner and outer pole teeth relative to the magnetic ring, creating balanced designs that are more tolerant to manufacturing variations. The symmetrical geometry provides self-aligning features and reduces sensitivity to misalignment, lowering the required manufacturing precision while maintaining torque performance.

Inventive Principle:
Principle #4Asymmetry

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 results in a smaller, more efficient, and cost-effective magnetic actuator that is easier to manufacture, improving robustness and reducing production costs while maintaining desired torque specifications.

Implementation Method 1

A current can be applied to the exciting coil to induce an electromagnetic torque between the pole piece and the permanent magnetic ring

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The magnetic actuator includes permanent magnets arranged around a ring that is attached to the valve spool

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP2028081B1Variable effort steering actuator
Publication Date: 2014.09.03 STEERING SOLUTIONS IP HOLDING CORP
  • EP2028081B1 patent drawingFigure 1
  • EP2028081B1 patent drawingFigure 2
  • EP2028081B1 patent drawingFigure 3~4

AI summary

A magnetic actuator (10), comprising, an inner ring (20), an outer ring (30) disposed around the inner ring, a first pair of inner teeth (21) disposed on the inner ring (20) that partially define a gap (23) between the first pair of inner teeth (20) having a first angular dimension, a second pair of inner teeth (Design 2) disposed on the inner ring (20) that partially define a gap between the second pair of inner teeth (Design 2) having a second angular dimension, a first pair of outer teeth (31) disposed on the outer ring (30) that partially define a gap (33) between the first pair of outer teeth (31) having a third angular dimension and a second pair of outer teeth (Design 2) disposed on the outer ring that partially define a gap between the second pair of outer teeth (Design 2) having a fourth angular dimension.