Multi-Axis Linear Motor Layout With Hall Sensor Position Detection
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Solution Overview
Problem
The high cost of position detection methods for multi-axis linear motor actuators limits their widespread adoption in applications requiring independent control of multiple axes, as existing solutions rely on expensive linear scales for position control.
Innovation Solution
A multi-axis linear motor actuator design incorporating a circuit board with Hall sensors and magnetic shielding plates, where the sensors are strategically placed to detect the position of linear shaft motors, allowing for cost-effective position control without reducing the pitch or size of the motor components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If linear scales are used for position detection in multi-axis linear motor actuators, then position control precision is improved, but device cost increases significantly
Solution Approach 1:
The patent replaces the mechanical linear scale system with a magnetic field-based detection system using Hall sensors. The Hall sensors detect the position of the shaft by sensing the magnetic field distribution generated by permanent magnets, eliminating the need for mechanical contact and complex scale mechanisms. This substitution significantly reduces device cost while maintaining position detection capability.
Solution Approach 2:
The patent introduces magnetic shielding plates as intermediaries to manage magnetic field distribution. These plates guide and shape the magnetic field to ensure accurate position detection by Hall sensors, while also preventing magnetic field interference between adjacent linear motors. The shielding plates act as a mediator between the permanent magnets and sensors, enabling precise measurement without direct mechanical interaction.
2Measurement precision
If Hall sensors are placed close to linear motors for position detection, then detection precision is improved, but magnetic field interference between adjacent motors increases
Solution Approach 1:
Magnetic shielding plates are positioned between adjacent linear motors to block and guide magnetic field lines. These plates prevent magnetic field leakage from one motor from interfering with the Hall sensors of adjacent motors, enabling close placement of sensors while maintaining detection precision. The shielding plates effectively segment the magnetic field zones of adjacent motors.
Solution Approach 2:
The patent applies magnetic shielding selectively at specific locations where magnetic field interference occurs between adjacent motors. The shielding plates are positioned only in the regions between motors, allowing the Hall sensors to remain close to the linear motors for high precision detection, while locally managing the magnetic field distribution to eliminate interference.
3Area of stationary object
If the pitch between adjacent linear motors is reduced for compactness, then device size is reduced, but magnetic field interference between motors increases
Solution Approach 1:
Magnetic shielding plates are introduced as intermediaries between adjacent linear motors to manage magnetic field interaction. These plates guide the magnetic field lines and prevent them from extending into adjacent motor regions, enabling reduced pitch between motors without suffering from magnetic field interference. The shielding plates effectively contain the magnetic field within each motor's designated zone.
Solution Approach 2:
The patent addresses the magnetic field interference problem by adding a spatial dimension solution - placing magnetic shielding plates in the third dimension (perpendicular to the motor axis) to block and redirect magnetic field lines. This allows the pitch between motors to be reduced in the horizontal plane without increasing magnetic interference, as the shielding plates create vertical barriers to field line propagation.
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 inexpensive position detection for multiple axes, reducing the overall cost of the multi-axis linear motor actuator while maintaining the necessary thrust force and compactness, thereby enhancing the efficiency and reliability of position control.
Implementation Method 1
a pair of Hall sensors installed in the circuit board in each of regions corresponding to the shafts
Implementation Method 2
a thrust force for driving the shaft in a center axis direction thereof is obtained by an action of a magnetic field generated by the permanent magnets and the currents flowing through the coils
Data Source
AI summary
A multi-axis linear motor actuator has a circuit board having a size covering coil portions in linear shaft motors arranged in a row, and combined with the linear shaft motors to be adjacent thereto and parallel to its arrangement direction; and magnetic shielding plates, longer than the coil portions, arranged and fixed along an axial direction at positions corresponding to positions between adjacent coil portions. Hall sensors are installed in the circuit board in each region corresponding to each linear shaft motor at intervals in a moving direction of a shaft of each linear shaft motor. Each magnetic shielding plate has a wide portion with a width greater than a diameter of the coil portion at a part corresponding to the region where the Hall sensors are installed. The circuit board has first slits for inserting the wide portions. The Hall sensors are installed adjacent to the wide portion.