Core-Type Linear Motor Coil Magnet Ratio Optimization
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Solution Overview
Problem
Existing core-type linear motors face challenges in achieving high motor constants with low cogging force and positive attraction, leading to increased load on linear slide rails and reduced service life due to suboptimal size ratios between coil assemblies and magnet units.
Innovation Solution
The configuration of three coil assemblies corresponding in length to four magnet units, with specific ratios for active and supporting core portions and magnet spacings, optimizes the size relationship to enhance motor constants and reduce attractive force-to-thrust force ratios, thereby extending the service life of linear slide rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the length ratio between coil assemblies and magnet units is not optimized, then the motor constant is reduced, but the attractive force-to-thrust force ratio increases
Solution Approach 1:
The patent applies parameter changes by optimizing the length ratio between coil assemblies and magnet units to a specific range (3:4 to 3:5), and by adjusting the active portion length ratio (0.3-0.5) and supporting portion height ratio (0.28-0.38). These parameter optimizations simultaneously improve the motor constant while reducing the attractive force-to-thrust force ratio, resolving the technical contradiction between power output and force balance.
2Force
If the attractive force-to-thrust force ratio is high, then the motor can generate sufficient thrust, but the load on linear slide rails increases and service life decreases
Solution Approach 1:
By optimizing the geometric parameters including the length ratio of coil assemblies to magnet units (3:4 to 3:5), the active portion length ratio (0.3-0.5), and the supporting portion height ratio (0.28-0.38), the patent reduces the attractive force-to-thrust force ratio. This parameter optimization maintains sufficient thrust force while minimizing the positive attraction that loads the linear slide rails, thereby extending their service life and improving 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 configuration results in a higher motor constant and lower attractive force-to-thrust force ratio, reducing the load on linear slide rails and extending their service life while maintaining low cogging forces.
Implementation Method 1
The rotor is provided opposite the stator and is configured to move linearly in the axial direction. The rotor includes a plurality of coil assemblies arranged side by side in the axial direction. Each coil assembly includes a core and a coil wound around the core.
Data Source
AI summary
A core-type linear motor includes: a stator extending in an axial direction, with magnets arranged at intervals in the axial direction, wherein each magnet and its spacing from an adjacent magnet constitute a magnet unit; and a rotor opposite the stator and linearly movable in the axial direction, with coil assemblies arranged side by side in the axial direction. Each coil assembly includes a core with an active portion wound with a coil and a supporting portion. Three coil assemblies have substantially the same length in the axial direction as four magnet units. When the length of each magnet unit is defined as 1, the length of each active portion is 0.3 to 0.5, and the height of each supporting portion, 0.28 to 0.38. These size ratios help increase the motor constant, lower the cogging force, and reduce positive attraction between the rotor and the stator.