Voice Coil Gimmick Actuator With Integrated Position Sensing
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Solution Overview
Problem
Existing gimmick devices in game machines face challenges with smooth linear motion due to backlash in rotation-to-linear conversion mechanisms and temperature-related deviations, leading to increased costs and drive mechanism enlargement when using voice coil motors.
Innovation Solution
A gimmick device incorporating a voice coil motor with a differential transformer configuration, where the drive and primary coil serve as both the drive mechanism and displacement sensor, utilizing two secondary coils to detect position without altering the motor's axial or radial size, and a drive control device that corrects target positions using high-frequency currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotation-to-linear movement conversion mechanism (rack and pinion or cam) is used with a rotary stepping motor, then the drive mechanism can operate the gimmick, but backlash in the conversion mechanism causes non-smooth operation and fails to achieve smooth floating motion
Solution Approach 1:
The patent replaces the rotation-to-linear movement conversion mechanism (rack and pinion or cam) with a voice coil motor that directly converts electrical energy to linear motion. This eliminates the mechanical backlash inherent in gear and cam systems, achieving smooth floating motion without position accuracy loss.
Solution Approach 2:
The voice coil motor integrates both drive and detection functions within a single component. The motor's coil and magnetic field structure enable it to both actuate the gimmick and detect its position, eliminating the need for separate conversion mechanisms and sensors.
2Ease of operation
If a linearly movable voice coil motor is used, then smooth reversal of linear direction is achieved, but temperature changes or component variations cause deviation between target and operating positions
Solution Approach 1:
The patent implements a feedback control system where the voice coil motor detects its own position through the differential transformer mechanism and compares it with the target position. The control unit adjusts the drive signal based on the detected deviation, compensating for temperature-induced drift and component variations to maintain accurate positioning.
Solution Approach 2:
The patent replaces separate mechanical position sensing mechanisms with an electromagnetic detection system integrated into the voice coil motor. The differential transformer uses electromagnetic induction to detect position without mechanical contact, eliminating mechanical wear and improving precision.
3Measurement precision
If a displacement sensor is provided to detect operating position and control to eliminate deviation, then position accuracy is improved, but the drive mechanism enlarges and cost increases
Solution Approach 1:
The patent merges the drive mechanism and position detection function into a single integrated voice coil motor assembly. The coil structure serves dual purposes: generating electromagnetic force for actuation and forming part of the differential transformer for position sensing. This eliminates the need for separate displacement sensors and reduces overall mechanism size.
Solution Approach 2:
The voice coil motor is designed to perform multiple functions simultaneously: it acts as both the actuator that moves the gimmick and the sensor that detects its position. The same magnetic field and coil structure enable both drive and detection, reducing component count and system complexity.
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
Enables consistent, smooth motion of gimmicks without enlarging the drive mechanism or increasing costs, achieving accurate position control and reducing temperature-related deviations.
Implementation Method 1
when a drive current is fed to the drive and primary coil, a thrust (Lorentz force) is generated in an axial direction of the drive and primary coil in accordance with Fleming's left-hand rule
Implementation Method 2
a position of the magnet side relative to the coil side is detected from a difference between voltages induced in the two secondary coils
Data Source
AI summary
A gimmick device according to one or more embodiments may include a gimmick and a voice coil motors (VCM). The VCM includes a casing, a permanent magnet, a yoke and iron-core, a bobbin, and a coil part. The gimmick is mounted to the casing on a movable side. The coil part includes a drive and primary coil serving as a drive coil and a primary coil of a displacement sensor including a differential transformer, the drive and primary coil being interlinked with a magnetic flux by the permanent magnet, and two secondary coils of the displacement sensor. The yoke and iron-core may be disposed in a central space defined in the coil part, and serves as an iron core of the displacement sensor.