Torque Detection Device with Shaped Annular Frame for Steering Systems

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Solution Overview

Problem

Existing torque detection devices for motor vehicle steering systems require complex and delicate overmolding processes, leading to issues such as high insertion forces, potential damage, and material infiltration, which complicates the manufacturing process and affects the device's functionality.

Innovation Solution

A torque detection device with a shaped annular frame that includes means for hooking and positioning the slip rings and an electromagnetic protection shield, allowing for a single overmolding operation, where the frame's elastic lugs and abutments maintain ring positioning and ensure even plastic distribution, preventing shield crushing and facilitating easier assembly and molding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the collector rings are overmolded by plastic material to form an annular mass, then the structure is integrated, but the process requires two successive molding operations and high insertion force which risks damaging the collector rings

Engineering Contradiction:
Improvestructure integrationVSAvoidmanufacturing process complexity
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The device is divided into separate components: collector rings, electromagnetic protection shield, and flux collector support. Each component is manufactured independently and then assembled together, avoiding the need for complex multi-step overmolding operations while maintaining structural integration through precise positioning means.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The collector rings and electromagnetic protection shield are pre-assembled on the flux collector support with positioning means before the final overmolding operation. This preliminary assembly allows for easier introduction into the mold and reduces insertion force requirements compared to introducing an already-formed annular mass.

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the flux collector support is overmolded with plastic material, then the structure is unified, but material infiltration occurs which masks the collector rings and alters their operation

Engineering Contradiction:
Improvestructural unityVSAvoidcollector ring operation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The collector rings are extracted from the final overmolding process and assembled separately on the flux collector support. The plastic material is then molded in a second operation, filling only the spaces between the rings and shield without penetrating into the rings themselves, thus preventing masking while achieving structural unity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The collector rings are positioned and secured on the flux collector support before the final overmolding operation. This preliminary positioning ensures that the rings are protected from plastic material infiltration during the molding process while still achieving the desired structural integration in the final assembly.

Inventive Principle:
Principle #10Preliminary action

3Productivity

If the flux collector support is introduced into overmolding tooling, then the device is manufactured, but high insertion force is required which risks damaging the collector rings

Engineering Contradiction:
Improvemanufacturing capabilityVSAvoidcollector ring integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The device is segmented into separately manufacturable components that are assembled before final molding. This segmentation allows the flux collector support with attached rings and shield to be introduced as a unit, reducing the insertion force required compared to introducing a solid annular mass while maintaining manufacturing productivity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The collector rings and electromagnetic protection shield are pre-assembled on the flux collector support with positioning means before introduction into the mold. This preliminary assembly creates a more compact and easier-to-introduce configuration that reduces insertion force requirements and protects the collector rings from damage during the molding process.

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 solution simplifies the manufacturing process by reducing the number of overmolding operations, ensuring precise positioning, and preventing material infiltration, resulting in a robust and flexible assembly that maintains the integrity of the components during molding.

Implementation Method 1

The framework comprises on its inner face a set of elastic lugs and abutments, which ensure the maintenance and the positioning, both axial and angular, of the collector rings

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

recessed areas, capable of allowing circulation and penetration of plastic material between the slip rings and the shield, during an overmolding operation of the device in the casing

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 3

the solid parts imposing a constant radial distance between said slip rings and the shield

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Data Source

PatentEP2423655B1Torque detection device with rotating ring for automobile steering system
Publication Date: 2013.08.07 JTEKT EUROPE SAS
  • EP2423655B1 patent drawingFigure 1~2
  • EP2423655B1 patent drawingFigure 3~4
  • EP2423655B1 patent drawingFigure 5

AI summary

The device has an annular magnetic flux collector carrier (1) comprising an annular framework (8) including solid parts formed of a ring gear (11) and straight or oblique elements (12) in the framework between one of collector rings (2, 3) and an electromagnetic protection shield (4) to impose a radial constant distance between the ring and the shield. The framework has recessed areas (18) to allow circulation and penetration of overmolding plastic material between the ring and the shield during overmolding operation of the device in a casing. An independent claim is also included for a method for manufacturing a torque detection device of a steering system of a motor vehicle.