Linear Actuator with Integrated Encoder for Position Detection
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Solution Overview
Problem
There is a significant need for an improved actuator that accurately sets and measures distance movement for precise movement applications, as existing technologies lack the necessary precision and reliability in detecting the position of a magnet assembly within a coil.
Innovation Solution
A linear motor with a bobbin having an interior axial opening and coils wound on its exterior, which creates a magnetic field to move a magnet assembly axially, combined with a built-in position sensor or encoder to detect the magnet's position, utilizing a moving magnet with steel pole heads and an encoder strip for precise positioning controlled by a motion controller.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a linear actuator uses a coil and magnet assembly to produce motion, then it achieves linear movement capability, but it lacks accurate position detection capability
Solution Approach 1:
The encoder is integrated directly into the actuator housing, merging the position detection function with the motion production function. The encoder scale is mounted on the magnet assembly while the encoder readhead is positioned in the housing, creating a unified actuator system that both produces motion and measures position accurately without requiring separate detection devices.
Solution Approach 2:
The actuator housing serves multiple functions: it contains the coil assembly, supports the magnet assembly, houses the encoder readhead, and provides structural support. This multi-functionality reduces the need for additional separate components, achieving accurate position detection while maintaining relatively simple device structure.
2Measurement precision
If the actuator includes an integrated encoder for position detection, then measurement precision improves, but device complexity increases
Solution Approach 1:
The encoder components (scale, readhead, housing) are merged into the actuator structure itself rather than being separate add-on components. The encoder scale is mounted directly to the magnet assembly and the readhead is positioned within the existing actuator housing, integrating position detection functionality without significantly increasing overall device complexity.
3Measurement precision
If the encoder scale is affixed to the moving magnet assembly, then position detection accuracy is achieved, but the risk of encoder damage during motion increases
Solution Approach 1:
The encoder scale is nested within the actuator housing structure, with the readhead positioned to read the scale as the magnet assembly moves through the housing. This nested arrangement protects the encoder components from external damage while enabling accurate position detection during magnet assembly motion.
Solution Approach 2:
The encoder scale acts as an intermediary element that translates the physical position of the magnet assembly into detectable signals for the readhead. By positioning the scale on the moving magnet assembly and the readhead in the stationary housing, the system achieves accurate position measurement while protecting the encoder components from direct exposure to external forces.
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 enables precise axial movement and accurate position detection of the magnet assembly, enhancing the precision and reliability of movement in linear actuator applications by utilizing the magnetic field and position sensor integration.
Implementation Method 1
electricity carrying coils wound on an exterior of the bobbin which creates a magnetic field when electricity runs through the wound coils
Implementation Method 2
The bobbin was encapsulated in a housing having one opened end which permitted axial motion of the bobbin when the magnetic field produced by the permanent magnet interacted with an electric current that passed through the wires
Data Source
AI summary
A linear motor which includes a bobbin with an interior lengthwise axial opening with a permanent magnet assembly within the opening and electricity carrying coils wound on an exterior of the bobbin which creates a force when electricity runs through the wound coils as a result of interaction between the magnetic field created by the magnet assembly, and the current passing through the coil wires, that enables the magnet assembly to move in an axial direction within the bobbin. The bobbin includes an encoder within an interior wall and an encoder scale strip affixed to the magnet assembly so that the encoder can detect the position of the magnet assembly.