Friction Welding Rib for Motor Vehicle Sensor Stator

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Solution Overview

Problem

Existing torque sensor devices for motor vehicles, particularly those used in steering systems, face challenges in the complex and costly laser welding process for attaching the magnetic stator part to the holder, which requires precise diameter matching and complex process control.

Innovation Solution

The use of a holder with a welding rib for friction welding, specifically ultrasonic welding, to securely attach the stator part, offering a simpler, less expensive, and more robust attachment method that prevents deformation and eliminates diameter tolerance issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If laser welding is used to attach the fastening element to the holder, then secure attachment is achieved, but the process becomes technologically demanding and complex

Engineering Contradiction:
Improveattachment strengthVSAvoidwelding process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent replaces the laser welding process with a press-fit mechanical assembly method. The fastening element is inserted into the holder through radial pressing rather than laser welding, eliminating the need for complex laser welding equipment and process control while achieving secure attachment through precise dimensional matching and interference fit

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

2Strength

If laser welding is used to attach the fastening element, then secure attachment is achieved, but expensive equipment is required

Engineering Contradiction:
Improveattachment strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent substitutes expensive laser welding equipment with simple press-fit assembly machinery. The fastening element is mechanically pressed into the holder using standard pressing equipment, dramatically reducing manufacturing costs while maintaining attachment strength through precise interference fit design

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

Solution Approach 2:

The patent employs a cost-effective fastening element design that can be manufactured using inexpensive materials and simple processes. The fastening element serves as a disposable or replaceable component that achieves its function through economical means rather than expensive welding processes

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Strength

If the fastening element diameter is precisely matched to the holder for press fit, then secure attachment is achieved, but the process becomes complex and demanding

Engineering Contradiction:
Improveattachment strengthVSAvoiddiameter tolerance precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The patent modifies the dimensional parameters of the fastening element and holder to create an optimized interference fit. By carefully selecting the press-fit tolerance range and dimensional ratios, the patent achieves secure attachment without requiring extremely tight tolerances, balancing manufacturing feasibility with attachment strength

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

This approach simplifies the attachment process, reduces costs, ensures secure fastening without deformation, and provides reliable connection through evenly distributed forces, enhancing the overall reliability and efficiency of the torque sensor device.

Implementation Method 1

The holder has a welding rib by means of which the holder is connected to the mounting element by friction welding

Methodology Applied
Scientific EffectFriction welding: Friction Welding

Implementation Method 2

specifically ultrasonic welding, to securely attach the stator part

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP2912425B1Sensor device for a motor vehicle and motor vehicle
Publication Date: 2019.03.27 VALEO SCHALTER & SENSOREN GMBH
  • EP2912425B1 patent drawingFigure 1
  • EP2912425B1 patent drawingFigure 2~3

AI summary

The invention relates to a sensor device (1) for measuring a variable that characterizes a rotational state of a shaft part in a motor vehicle, in particular a steering shaft in the motor vehicle. Said sensor device comprises a holder (2) that can be connected to the shaft part in the motor vehicle, and a magnetic stator part (3) that is arranged on the holder (2), is designed to conduct magnetic flux from a magnet to a magnet sensor, and has an annular radial base element (5), the axial front side (12) of which is axially supported on the holder (2). The sensor device further comprises a fastening element (4) which allows the stator part (3) to be secured at least in the axial direction to the holder (2) from its axial rear side (13) located across from the front side (12). The holder (2) has at least one welding rib (18), by means of which the holder (2) is connected to the fastening element (4) in a friction welding process.