Linear Actuator with Moving Coil and Permanent Magnets
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Solution Overview
Problem
Current linear actuators, particularly those used in electronic assembly, face challenges with high manufacturing costs and the need for small diameters to accommodate tight spaces, as well as potential damage to fragile components due to friction forces from pneumatic slides, which have limited lifetimes.
Innovation Solution
A low-cost, reduced-diameter linear actuator design featuring a base and top housing with recesses for magnets, a piston assembly with coil bobbins and a linear encoder scale, and a method of manufacturing that includes steel casting and plastic molding to reduce parts and machining costs, utilizing flat coils for reduced thickness and increased durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pneumatic slides are used for manipulation, then the actuators are inexpensive, but the friction forces cause damage to small and fragile components
Solution Approach 1:
The patent replaces the pneumatic mechanical system with a magnetic field-based system. Magnets are embedded in the housing to create magnetic fields that interact with a coil assembly, eliminating the need for pneumatic components and their associated friction forces that damage fragile electronic parts.
Solution Approach 2:
The patent eliminates pneumatic slides entirely and replaces them with an electromagnetic actuation system using magnets and coil bobbins, thereby removing the source of friction-based damage to components while maintaining actuation functionality.
2Ease of manufacture
If pneumatic slides are used, then the actuators are inexpensive, but the lifetime is limited to less than 10M cycles
Solution Approach 1:
The patent replaces wear-prone pneumatic mechanical components with a magnetic field-based system that has no contacting moving parts, thereby eliminating mechanical wear and extending actuator lifetime beyond 10M cycles while maintaining cost-effectiveness.
3Duration of action of stationary object
If magnetic actuators are used to reduce friction and extend lifetime, then the lifetime increases beyond 10M cycles, but the manufacturing cost increases
Solution Approach 1:
The patent divides the magnetic actuator system into discrete magnet assemblies embedded in the housing and separate coil bobbins mounted on the piston, allowing independent manufacturing and assembly of components to reduce overall manufacturing cost while maintaining extended lifetime benefits.
Solution Approach 2:
The patent designs the magnet assemblies to serve multiple functions: generating magnetic fields for actuation, providing structural support, and enabling soft-landing capability, thereby reducing the need for additional components and lowering manufacturing cost.
4Volume of moving object
If the actuator diameter is reduced to less than 8 mm for tight spaces, then the actuator can be used in electronic assembly, but the manufacturing precision requirements increase
Solution Approach 1:
The patent nests the coil bobbins within the piston assembly and the magnet assemblies within the housing, allowing compact arrangement of components that achieves sub-8mm diameter while maintaining adequate manufacturing tolerances through efficient space utilization.
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 cost-effective, long-lasting linear actuator that can handle small components with reduced risk of damage, offering a viable replacement for pneumatic slides with a tenfold increase in cycle life and manufacturing costs reduced by 75%.
Implementation Method 1
one or more wire coils of the at least one coil bobbin are in one or more planes parallel to a line of motion of the movable assembly
Implementation Method 2
at least one recess configured to restrain at least one magnet in three dimensions
Data Source
AI summary
A linear actuator, comprising a base housing, a top housing, and a piston assembly. The base housing may include at least one recess configured to restrain at least one magnet in three dimensions and a channel configured to receive a linear guide. The top housing may be fixedly attached to the base housing and may include at least one recess configured to restrain another at least one magnet in three dimensions. The piston assembly may include at least one coil bobbin, a shaft, a linear encoder scale, and a flex cable, wherein the piston assembly may be positioned between the base housing and the top housing.