Linear Motor Thermal Isolation for Precise Transport Positioning
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Solution Overview
Problem
Moving magnet type linear motors face challenges in achieving precise positioning and repeatability due to heat generated by coils, which affects transport speed and inclination, and are prone to dust generation and cable disconnection issues in precision manufacturing environments.
Innovation Solution
Incorporating a heat conduction reduction portion between the excitation and acting units of the linear motor, using thermal insulation materials to minimize heat transfer and separate the coil and permanent magnet components, and configuring the transport apparatus to eliminate the need for cableveyors, thereby reducing dust generation and cable disconnection risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If coils are arranged closer to permanent magnets to reduce motor size, then compactness is improved, but heat conduction from coils to permanent magnets increases causing positioning accuracy degradation
Solution Approach 1:
A heat conduction reduction portion is introduced as an intermediary between the coil and the permanent magnet. This portion has lower heat conduction than direct contact, thereby reducing heat transfer from the coil to the permanent magnet while allowing the components to remain in close proximity for compact motor design.
Solution Approach 2:
The heat conduction reduction portion is specifically positioned only where heat conduction needs to be reduced (between coil and permanent magnet), while other parts of the motor maintain direct contact for structural integrity and magnetic coupling. This localized application allows compactness in most areas while preventing heat transfer at the critical interface.
2Reliability
If connection cables are used for movable track units, then electrical connection is improved, but dust generation and cable disconnection occur due to sliding and bending
Solution Approach 1:
The patent replaces the mechanical cable connection system with a contactless power transmission system using magnetic coupling. This eliminates the mechanical sliding and bending of cables, thereby preventing dust generation from cable wear while maintaining reliable electrical connection through electromagnetic induction.
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 effectively suppresses the impact of heat on positioning accuracy, enhances repeatability, and prevents dust and cable issues, enabling a compact, precise, and reliable transport apparatus suitable for precision manufacturing applications.
Implementation Method 1
an airgap or a heat conduction reduction portion between the excitation unit and the acting unit, wherein the heat conduction reduction portion reduces heat conduction from the excitation unit to the acting unit more than in a case where the excitation unit and the acting unit are in direct contact with each other
Implementation Method 2
a plurality of coils serving as a stator are arranged along a track on which a movable element travels, and controlled drive current is supplied to driving coils to magnetically drive the movable element
Implementation Method 3
an acting unit configured to be magnetically coupled to the excitation unit and cause a magnetic flux applied from the excitation unit to work on the permanent magnet of the movable element
Implementation Method 4
the coils supplied with current in driving generate heat due to Joule heat
Data Source
AI summary
The disclosed linear motor includes a stator having a plurality of cores and coils that excite the plurality of cores, respectively, and a movable element having a permanent magnet and configured to move using electromagnetic force applied from the stator as driving force, each of the plurality of cores has an excitation unit wound with the coil and an acting unit configured to be magnetically coupled to the excitation unit and cause a magnetic flux applied from the excitation unit to work on the permanent magnet of the movable element, and the linear motor includes an airgap or a heat conduction reduction portion between the excitation unit and the acting unit, and the heat conduction reduction portion reduces heat conduction from the excitation unit to the acting unit more than in a case where the excitation unit and the acting unit are in direct contact with each other.