Plastic Speed Target Wheel With Embedded Ferrous Regions

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Solution Overview

Problem

Existing metal target wheels for sensors in mechanical devices are heavy, expensive, and require complex manufacturing processes, making them unsuitable for efficient and cost-effective speed measurement in applications like power transmissions.

Innovation Solution

A plastic speed target wheel with integrally formed ferrous regions in the gear teeth, where the ferrous material is embedded within the plastic, allowing for lightweight and cost-effective production through injection molding, and exposed to generate a signal in Hall effect sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metal target wheels are used for speed measurement, then the target wheel has sufficient strength and magnetic properties for sensor detection, but the target wheel becomes heavy and expensive with complex manufacturing requirements

Engineering Contradiction:

Improvesensor detection capabilityVSAvoidtarget wheel weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies composite materials by combining plastic (for lightweight structure) with ferrous particles or coatings (for magnetic detection properties). This creates a hybrid material that achieves both lightweight characteristics and sufficient magnetic response for Hall effect sensor detection, resolving the contradiction between weight and sensor detection capability.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent applies local quality by concentrating ferrous material specifically at the tooth tips rather than throughout the entire wheel. This localized approach provides sufficient magnetic signal at the detection point while minimizing overall weight, as the ferrous material is only placed where it is functionally necessary for sensor interaction.

Inventive Principle:

Principle #3Local quality

2Strength

If metal target wheels are used for speed measurement, then the target wheel provides adequate structural strength, but the manufacturing cost and process complexity increase

Engineering Contradiction:

Improvetarget wheel strengthVSAvoidmanufacturing simplicity

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

The patent uses composite materials where plastic provides the base structural strength and ferrous particles/coatings provide the necessary magnetic properties. This combination allows for simpler manufacturing processes compared to machining metal wheels, as the plastic component can be formed using injection molding or similar techniques.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent replaces traditional mechanical machining of metal wheels with molding processes for the plastic component. This substitution of manufacturing methods significantly reduces process complexity and cost, while the embedded ferrous material maintains the necessary functional properties for sensor detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Weight of moving object

If ferrous material is embedded in plastic gear teeth, then the target wheel becomes lightweight and cost-effective, but the ferrous material must be precisely positioned to generate sensor signals

Engineering Contradiction:

Improvetarget wheel weightVSAvoidferrous material positioning

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-positioning ferrous particles or coatings into the mold cavities before injecting the plastic material. This ensures that the ferrous material is automatically placed in the correct locations (at the tooth tips) during the molding process itself, achieving precise positioning without requiring subsequent machining or assembly operations.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies the nesting principle by embedding ferrous particles within the plastic matrix during the molding process. The ferrous material is nested into predetermined locations in the mold, and the plastic material surrounds and secures it, achieving precise positioning through the integrated molding process rather than separate operations.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 provides a lightweight, cost-effective speed target wheel that effectively generates signals for speed measurement in sensors, reducing manufacturing complexity and costs while maintaining accuracy.

Implementation Method 1

the ferrous region is included in each of the gear teeth in an amount and is disposed at a location that is effective to generate a signal in a Hall effect sensor disposed for reading the movement of the ferrous region

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS9291479B2Plastic speed target wheel and method of manufacture

Publication Date: 2016.03.22 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A speed target wheel includes an annular body portion and a plurality of gear teeth. The annular body portion consists of a plastic material and the plurality of gear teeth project from the annular body portion. Each of the plurality of gear teeth includes a base portion adjacent the annular body portion and a tip portion, where the base portion is integrally formed with the annular body portion and substantially comprises the plastic material, and where the tip portion includes a ferrous region integrally encompassed by the plastic material.