In-Vehicle Actuator Nonmagnetic Metal Cover Layout

Solution Overview

Problem

Existing motor controllers for in-vehicle units face challenges in size and ease of layout due to the combination of metal motor housings and resin covers, which can compromise airtightness and layout flexibility.

Innovation Solution

An actuator design featuring a nonmagnetic metal cover that covers the magnet and motor shaft through-hole, allowing for a smaller size and improved layout ease by using a metal cover made from the same material as the motor housing, such as aluminum alloy, to reduce thermal stress and rust, and incorporating a seal agent for enhanced sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resin cover is used to cover the magnet and motor shaft through-hole, then airtightness is improved, but the device size increases and ease of layout deteriorates

Engineering Contradiction:

ImproveairtightnessVSAvoiddevice size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent merges the cover function with the existing metal housing structure by adding a flange portion to the metal cover that integrates with the housing. This eliminates the need for a separate resin cover while maintaining airtightness through the metal-metal interface and seal agent, thereby reducing overall device size and improving ease of layout.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a composite sealing approach using both a metal cover with flange and a seal agent (rubber or resin material) to achieve airtightness. This composite solution combines the structural integrity and compactness of metal with the sealing effectiveness of elastomeric materials, avoiding the need for a bulky all-resin cover.

Inventive Principle:

Principle #40Composite materials

2Reliability

If a resin cover is used to cover the magnet and motor shaft through-hole, then airtightness is improved, but ease of layout deteriorates

Engineering Contradiction:

ImproveairtightnessVSAvoidease of layout

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent merges the cover function with the existing metal housing structure by adding a flange portion to the metal cover that integrates with the housing. This eliminates the need for a separate resin cover while maintaining airtightness through the metal-metal interface and seal agent, thereby reducing overall device size and improving ease of layout.

Inventive Principle:

Principle #5Merging (Combining)

3Volume of moving object

If a metal cover is used instead of resin cover, then device size is reduced and ease of layout is improved, but thermal stress and rust issues may arise

Engineering Contradiction:

Improvedevice sizeVSAvoidthermal stress and rust resistance

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

The patent uses a metal cover made from the same material as the motor housing (aluminum alloy), ensuring homogeneous material properties. This eliminates galvanic corrosion between dissimilar metals and ensures consistent thermal expansion characteristics, reducing thermal stress while maintaining the compact metal construction.

Inventive Principle:

Principle #33Homogeneity

Solution Approach 2:

The patent employs a composite sealing approach using both a metal cover with flange and a seal agent (rubber or resin material) to achieve airtightness. This composite solution combines the structural integrity and compactness of metal with the sealing effectiveness of elastomeric materials, avoiding the need for a bulky all-resin cover.

Inventive Principle:

Principle #40Composite materials

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 more compact and easily layout-able actuator with reduced foreign substance ingress and minimal magnetic field interference, while maintaining structural integrity and preventing thermal and rust-related issues.

Implementation Method 1

a cover made of nonmagnetic metal and structured to cover the motor shaft through-hole of the partition wall

Methodology Applied

Scientific EffectMagnetic field blocking: Magnetic Field

Implementation Method 2

a rotation sensor configured to monitor a rotational position of the motor shaft, based on variation in magnetic field from the magnet due to rotation of the magnet

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS11251673B2Actuator for in-vehicle unit

Publication Date: 2022.02.15 ASTEMO LTD

AI summary

A motor is contained in a motor container space. A controller is contained in a controller container space. The motor container space and the controller container space are arranged in series in a direction of a rotation axis of a motor shaft, while interposing a partition wall therebetween. The motor shaft is inserted in a motor shaft through-hole of the partition wall. A magnet is disposed at an end of the motor shaft, in the controller container space. A rotation sensor is disposed in the controller container space oppositely to the magnet, for monitoring a rotational position of the motor shaft on the basis of variation in magnetic field due to rotation of the magnet. A cover made of nonmagnetic metal is disposed between the magnet and the rotation sensor so as to cover the motor shaft through-hole.