Multi-turn Absolute Encoder with Gear Brake for Battery-Free Position Storage
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Solution Overview
Problem
Existing motor systems with battery-backed multi-turn absolute encoders require frequent battery replacements due to high current consumption, necessitating a solution for detecting multi-turn positions after startup without continuous power.
Innovation Solution
A motor system incorporating a multi-turn absolute encoder with an absolute angular position detection device and a storage element, along with a gear-type brake mechanism, allowing detection of multi-turn positions at startup even when the encoder is stopped, and eliminating the need for a backup battery by using a nonvolatile storage element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multi-turn absolute encoder is backed up by a battery to detect multi-turn position during stop period, then the detection capability is improved, but the current consumption increases requiring frequent battery replacement
Solution Approach 1:
The position detection function is segmented into two parts: (1) an absolute angular position detection device that detects position within one rotation period, and (2) a storage element that stores the rotation number. This segmentation eliminates the need for continuous battery power while maintaining multi-turn position detection capability.
Solution Approach 2:
The patent replaces the battery-backed continuous power system with a mechanical brake mechanism combined with a nonvolatile storage element. The brake mechanism physically prevents rotation shaft variations during stops, substituting the need for continuous electrical power with a mechanical holding system.
2Use of energy by moving object
If the absolute angular position detection device is stopped while the motor is stopped, then the current consumption is reduced, but the multi-turn position detection becomes inaccurate due to rotation shaft variations
Solution Approach 1:
The brake mechanism is engaged before stopping the absolute angular position detection device to prevent rotation shaft variations. This prior mechanical cushioning ensures that when the detection device restarts, the rotation shaft is in the same position, maintaining detection accuracy without requiring continuous power.
Solution Approach 2:
The brake mechanism acts as an intermediary between the motor and the absolute angular position detection device. It mediates the stopping process by physically holding the rotation shaft in place, allowing the detection device to be stopped without causing position drift.
3Reliability
If a backup battery is used for the storage element, then the rotation number is preserved during stops, but the system complexity and cost increase
Solution Approach 1:
The patent extracts the battery component from the storage element system by using a nonvolatile memory that inherently preserves data without power. This extraction simplifies the system by removing the backup battery while maintaining the rotation number preservation function.
Data Source
AI summary
A motor system includes a motor, and a multi-turn absolute encoder that detects a rotation number and an absolute angular position of a rotation shaft of the motor. The multi-turn absolute encoder includes: an absolute angular position detection device that detects the absolute angular position within one rotation period of the rotation shaft; and a storage element that stores the rotation number of the motor. Even if the driving of the multi-turn absolute encoder is stopped while the motor is stopped, the multi-turn absolute encoder detects the multi-turn position of the rotation shaft after startup. Further, the motor has a brake mechanism including: a gear-type brake wheel that rotates integrally with the rotation shaft; an engagement member capable of engaging with the teeth of the gear-type brake wheel; and an actuator which causes the teeth and the engagement member to engage with each other during braking.