Machining Apparatus Using Magnetic Repulsion for Thrust Ripple Reduction
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Solution Overview
Problem
High-speed machining of diffraction gratings and light guide plates requires precise linear motion with minimal vibration and heat generation, as existing solutions like linear motors generate significant thrust ripples and cogging, affecting precision and efficiency.
Innovation Solution
A machining apparatus with a sliding member and guide member supported by a fluid dynamic bearing, utilizing repulsive forces from strategically placed permanent magnets to reduce the thrust force required for reciprocating motion, combined with a linear motor and a piezoelectric device for precise cutting depth control, minimizing heat generation and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a linear motor is used to reciprocate the sliding member at high speed, then productivity is improved, but heat generation increases and machining precision deteriorates
Solution Approach 1:
The patent utilizes the repulsive force generated by permanent magnets at the reversal points to convert the harmful effect of high acceleration (which causes heat generation) into a beneficial force that assists the linear motor in reversing the sliding member's motion. The permanent magnets are positioned to repel each other when the sliding member approaches the ends of its stroke, providing an additional driving force that reduces the burden on the linear motor and minimizes heat generation while maintaining high-speed reciprocating motion.
2Speed
If a linear motor is used to generate high thrust force, then speed is improved, but thrust ripples and cogging occur affecting straightness accuracy
Solution Approach 1:
The patent positions permanent magnets on the sliding member and guide member to generate repulsive forces that counteract the thrust ripples and cogging effects of the linear motor. The repulsive force from the permanent magnets provides a smoothing effect on the driving force, eliminating the periodic variations in thrust that cause vibration and affect straightness accuracy during high-speed reciprocating motion.
3Productivity
If high acceleration is applied at reversal points to maintain high speed reciprocating motion, then productivity is improved, but heat generation from the driving unit increases
Solution Approach 1:
The patent strategically positions permanent magnets to generate repulsive forces precisely when the sliding member approaches the ends of its stroke. This repulsive force provides additional acceleration assistance at the critical reversal points, enabling high reciprocating frequency without requiring excessive thrust from the linear motor, thereby reducing heat generation while maintaining high productivity.
4Force
If additional permanent magnets are placed at both ends of the array to reduce thrust force at reversal, then force requirement is improved, but device complexity increases
Solution Approach 1:
The patent combines the functions of the permanent magnets into a unified magnetic field system where the first and second permanent magnets work together to generate the repulsive force. The magnets are positioned to create a coordinated magnetic interaction that reduces thrust force requirements while maintaining a relatively simple overall structure. The merging of magnetic fields from multiple magnets creates a synergistic effect that achieves force reduction without proportionally increasing device complexity.
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
Enables high-speed, high-precision linear grooving with reduced heat generation and vibration, preventing thrust ripples and cogging, thus improving machining accuracy and efficiency.
Implementation Method 1
a guide member that supports the sliding member in a linearly movable manner via a bearing
Implementation Method 2
the first and second permanent magnets repel one another, exerting a repulsive force in the sliding member in an axial direction of the guide member
Implementation Method 3
a linear driving unit that includes a sliding member to which a tool is attachable and a guide member that supports the sliding member in a linearly movable manner via a bearing
Implementation Method 4
combined with a linear motor and a piezoelectric device for precise cutting depth control
Data Source
AI summary
A sliding member having an attached tool reciprocates along a guide member. Permanent magnets are placed at both ends of the reciprocating motion path of the sliding member and permanent magnets are also placed in positions on the guide member that correspond to stroke ends of the sliding member. At the points at which the motion of the sliding member reverses, the permanent magnets approach one another and generate a repulsive force, thereby accelerating the sliding member.