Magnetic Shielding Shell for Interference-Resistant Non-Contact Control

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Solution Overview

Problem

Existing non-contact control switches for electric tools are susceptible to external magnetic interference, leading to inaccurate speed regulation, reduced control accuracy, unstable operation, and safety risks, particularly in high-precision applications.

Innovation Solution

A non-contact control assembly with a magnetic shielding shell having a three-dimensional closed loop structure that encases a magnetic sensor and element, allowing the sensor to move within the shell to effectively shield against external magnetic interference, ensuring precise speed and torque control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an outer shielding cover is used to block external magnetic interference, then magnetic shielding capability is improved, but device volume increases and manufacturing complexity increases

Engineering Contradiction:

Improveexternal magnetic interferenceVSAvoiddevice volume

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The magnetic shielding element is nested within the control assembly housing, integrating the shielding function into the existing structure rather than adding an external cover. This allows the shielding capability to be embedded within the device boundaries, avoiding volume increase while maintaining protection against magnetic interference.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

The control assembly housing serves multiple functions: it provides structural support, houses control components, and acts as a magnetic shielding barrier. By making the housing multi-functional, the patent eliminates the need for separate shielding covers, thereby avoiding increased device volume and manufacturing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If an outer shielding cover is used to block external magnetic interference, then magnetic shielding capability is improved, but manufacturing processes become more complex

Engineering Contradiction:

Improveexternal magnetic interferenceVSAvoidmanufacturing processes

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The control assembly housing is designed to simultaneously provide structural support, component housing, and magnetic shielding functions. This multi-functionality reduces the total number of parts and assembly steps, simplifying manufacturing processes while maintaining effective magnetic interference protection.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The magnetic shielding function is merged with the control assembly housing structure, eliminating the need for separate shielding cover manufacturing and assembly. This consolidation reduces manufacturing complexity by decreasing the number of discrete components and assembly operations required.

Inventive Principle:

Principle #5Merging (Combining)

3Object-affected harmful factors

If magnetic shielding material is increased to improve shielding effectiveness, then magnetic shielding capability is improved, but device volume and material usage increase

Engineering Contradiction:

Improveexternal magnetic interferenceVSAvoidmagnetic shield materials

Core Design Contradiction:

Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The magnetic shielding capability is applied locally where most needed - within the control assembly housing surrounding the sensitive components. This localized approach provides effective shielding against magnetic interference while minimizing the total quantity of magnetic shield materials required, avoiding unnecessary material usage and volume increase.

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 magnetic shielding design significantly reduces external magnetic interference, enhancing the precision and reliability of electric tool operation while maintaining a compact size and reducing manufacturing complexity.

Implementation Method 1

uses a magnetic sensor (such as a linear Hall effect sensor or a magnetoresistive effect sensor)

Methodology Applied

Scientific EffectHall effect: Hall Effect

Implementation Method 2

a magnetic shielding shell, operably connected to the actuator, and the magnetic element being mounted to the actuator and located in the magnetic shielding shell

Methodology Applied

Scientific EffectMagnetic shielding: Magnetic Field

Data Source

PatentUS20250364934A1Non-contact control assembly for controlling operation of electrical device

Publication Date: 2025.11.27 DEFOND ELECTECH CO LTD

AI summary

The present application relates to a non-contact control assembly using a magnetic sensor, including a control assembly housing; a magnetic sensor; a magnetic element; an actuator; a connection port, for establishing a power and signal connection with a motor control module; and a magnetic shielding shell, operably connected to the actuator, and the magnetic element being mounted to the actuator and located in the magnetic shielding shell. The magnetic shielding shell includes a three-dimensional closed loop structure having two open surfaces, in response to the movement of the actuator relative to the control assembly housing, the magnetic sensor is able to enter an interior of the magnetic shielding shell through one of the open surfaces of the magnetic shielding shell and move towards the other of the open surfaces of the magnetic shielding shell relative to the magnetic element in the interior of the magnetic shielding shell.