Axial Optical-Magnetic Encoder Layout for Compact Servo Motors
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Solution Overview
Problem
There is a demand for further miniaturization of encoder devices to improve their compactness and efficiency in servo systems.
Innovation Solution
The encoder system includes a rotating body with a disk having a ring-shaped scale, an optical module for detecting the scale, a magnet, and a magnetic detector, which together enable the detection of position, speed, and acceleration, while being compactly designed to fit within a servo motor system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the encoder device is miniaturized, then the compactness and integration efficiency are improved, but the detection precision and operational reliability may deteriorate
Solution Approach 1:
The encoder is divided into functionally independent modules: optical detection module (for position), magnetic detection module (for speed and acceleration), signal processing module, and power supply module. Each module is optimized independently, allowing the optical module to maintain high position detection precision while the magnetic module handles dynamic parameters, thus preserving measurement precision during miniaturization.
Solution Approach 2:
The patent utilizes the axial dimension (thickness direction) of the encoder to arrange components in layers rather than spreading them radially or circumferentially. The optical module is positioned on one face of the disk while the magnetic detector is positioned on the opposite face, effectively using the third dimension to reduce the encoder's radial and circumferential footprint while maintaining functional performance.
2Volume of moving object
If the encoder device is miniaturized, then the compactness is improved, but the power consumption management becomes more challenging
Solution Approach 1:
The patent implements periodic power supply to the optical detection system using a battery-powered intermittent operation mode. The optical module is activated only when position detection is required, while the magnetic detection system operates continuously for speed and acceleration monitoring. This periodic activation significantly reduces average power consumption, enabling miniaturization without compromising operational reliability.
Solution Approach 2:
The encoder incorporates an integrated battery and power management circuit that autonomously supplies power to the optical module when needed, without requiring external power sources. The magnetic detector uses passive magnetic field detection that consumes minimal power, and the system self-regulates power distribution based on operational requirements, reducing overall power consumption for the miniaturized device.
3Volume of moving object
If the encoder device is miniaturized, then the integration efficiency is improved, but the structural complexity increases
Solution Approach 1:
The patent combines multiple detection functions into a single integrated encoder disk structure. The optical scale is etched directly onto the disk surface, and the magnetic detector is mounted on the opposite face of the same disk, merging position and dynamic parameter detection into one unified component. This integration reduces the number of separate parts and simplifies assembly, offsetting the increased functional complexity through structural consolidation.
Solution Approach 2:
The encoder disk serves multiple functions simultaneously: it acts as the mounting substrate for the optical scale, provides the rotating element for position detection, and supports the magnetic detector for speed and acceleration measurement. The single disk structure performs what would traditionally require multiple separate components, reducing overall structural complexity despite the multi-functional requirements.
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 allows for the miniaturization of encoder devices, enhancing their integration within servo systems and improving detection accuracy while maintaining operational efficiency.
Implementation Method 1
an optical module that is disposed to face the disk and detects the scale
Implementation Method 2
a first magnetic detector that is disposed on the other side from the disk in the direction of the rotation axis and detects magnetism of the first magnet
Data Source
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AI summary
An encoder includes a rotating body that is rotatable around a rotation axis; a disk that is fixed to the rotating body and has a scale formed in a ring shape; an optical module that is disposed to face the disk and detects the scale; a first magnet that is disposed on one side from the disk in a direction of the rotation axis and fixed to the rotating body; and a first magnetic detector that is disposed on a remaining side from the disk in the direction of the rotation axis and detects magnetism of the first magnet.