Linear Motor Movable Element with Segmented Nonmagnetic Holder
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Solution Overview
Problem
Conventional linear motors face challenges in achieving high-speed and high-acceleration movement while maintaining weight reduction, as weight reduction leads to reduced rigidity and deflection deformation, causing gaps between the movable element and stator to become uneven, which hampers movement and shortens the lifespan of guided parts and guide rails.
Innovation Solution
The linear motor design includes a stator with magnetic pole teeth and a movable element with a nonmagnetic holder featuring holding holes and thinning holes along the movement direction, which function as positioning parts to maintain a uniform gap and enhance rigidity, allowing for higher speeds and acceleration without increasing the size of guided parts and guide rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the movable element is reduced in weight to enable high-speed and high-acceleration movement, then the speed and acceleration improve, but the rigidity decreases causing deflection deformation and uneven gaps between the movable element and stator
Solution Approach 1:
The movable element is segmented into a magnetic pole tooth portion and a holder portion, allowing independent optimization of each component's properties for weight reduction and rigidity maintenance
Solution Approach 2:
The holder is made of nonmagnetic material with higher rigidity than conventional movable elements, creating a composite structure that achieves both weight reduction and enhanced rigidity to prevent deflection at high speeds
2Productivity
If the movable element is reduced in weight, then the movement performance improves, but the gap uniformity between the movable element and stator deteriorates due to deflection
Solution Approach 1:
The bottom surface of the magnetic pole tooth is formed with a curved shape that compensates for the deflection of the holder, ensuring that the gap between the movable element and stator remains uniform even during high-speed operation
Solution Approach 2:
The curvature radius of the bottom surface is specifically designed to match the expected deflection amount, dynamically compensating for deformation under different operating conditions
3Reliability
If the size of guided parts and guide rails is increased to support high-speed movement, then the reliability improves, but the device complexity and size increase
Solution Approach 1:
The holder is designed with a nonmagnetic material that has higher rigidity than conventional movable elements, converting the potential harm of weight reduction into a benefit of enhanced rigidity that reduces the load on guided parts, allowing smaller guided parts to be used while maintaining reliability
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
This design enables the movable element to maintain proper positional relationships at high speeds and accelerations, preventing deflection and deformation, thereby extending the lifespan of guided parts and guide rails while allowing for a reduction in size and weight.
Implementation Method 1
stators as primary side magnetic field generating members having coils; a movable element as a secondary side member disposed at a position opposing to the stator via a prescribed gap
Implementation Method 2
stators having first magnetic pole teeth capable of forming a magnetic field; movable element including a second magnetic pole tooth capable of forming a magnetic field
Data Source
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AI summary
A linear motor (L) provided with: a stator (2, 3) in which first magnetic pole teeth (22, 32) are disposed at a prescribed pitch along the movement direction (A) of a movable element (4); and the moveable element (4), which has second magnetic pole teeth (41) disposed at a prescribed pitch along the movement direction (A), and a nonmagnetic holder (42) for holding the second magnetic pole teeth (41), wherein thinning holes (422) and holding holes (421) capable of holding the second magnetic pole teeth (41) are alternatingly formed in the holder (42) along the movement direction (A), the boundary portions (423) of the holding holes (421) and the thinning holes (422) adjacent in the movement direction (A) in the holder (42) being caused to function as positioning parts in the movement direction (A) for the second magnetic pole teeth (41), whereby the magnetic pole teeth of the moveable element can be continually held in the prescribed position even during motion of the moveable element at high speed and high acceleration, and correct action of the linear motor can be secured, while reducing the weight of the moveable element.