Vertical BLDC Swivel Actuator Layout for Low Backlash Torque Drive
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Solution Overview
Problem
Conventional actuators face issues with complex assembly structures, increased costs, and difficulty in securing assembly space due to the use of DC motors with external casings, as well as challenges in precise position control and vibration due to multiple spur gears and Hall sensors.
Innovation Solution
A swivel actuator with a BLDC motor vertically integrated into the housing, featuring a power transmission structure where a worm wheel and worm gear are integrally formed on a power transmission shaft, minimizing the number of coupling gears and incorporating a symmetrical gear train design to reduce backlash and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a DC motor with external casing is used, then the motor structure is simple and cost-effective, but the assembly space requirement increases and housing height increases
Solution Approach 1:
The patent merges the motor and gear train into a single integrated unit. The DC motor casing directly houses the gear train components, eliminating the need for separate motor housing and reducing overall assembly space. The worm gear shaft is directly coupled to the motor shaft, and the planetary gear mechanism is positioned within the motor casing, achieving compact integration.
2Power
If multiple spur gears are used for torque conversion, then the reduction ratio is achieved, but the device complexity increases and backlash increases
Solution Approach 1:
The patent combines a worm gear mechanism with a planetary gear mechanism into a single integrated gear train. The worm gear provides both torque multiplication and self-locking capability, while the planetary gear mechanism provides additional reduction ratio. This merged approach achieves high torque output with fewer components compared to using multiple separate spur gears.
Solution Approach 2:
The worm gear in the patent serves multiple functions: it provides torque conversion through reduction, acts as a brake mechanism due to its self-locking property, and eliminates the need for separate braking components. This multi-functionality reduces overall device complexity while maintaining high torque capability.
3Measurement precision
If a Hall sensor is used for position sensing, then precise position control is achieved, but the connection structure becomes complicated
Solution Approach 1:
The patent integrates the Hall sensor directly into the motor assembly, positioning it within the motor casing near the rotor magnets. This integration eliminates the need for external sensor mounting and complex wiring connections. The sensor signals are directly routed to the control circuit board through the motor housing, simplifying the overall connection structure.
4Length of stationary object
If the housing height is reduced for compact design, then the product size is minimized, but the assembly space for motor and gear train is insufficient
Solution Approach 1:
The patent employs a nested arrangement where the gear train components are positioned inside the motor casing. The planetary gear mechanism is located within the motor housing, and the worm gear shaft passes through the motor shaft. This nesting approach allows the gear train to occupy the internal volume of the motor housing, effectively utilizing the available space and reducing overall housing height.
Solution Approach 2:
The patent transitions from a horizontal layout to a vertical arrangement of components. The motor shaft is oriented vertically, and the gear train is arranged along the vertical axis within the motor casing. This dimensional change allows for more efficient space utilization and reduces the horizontal footprint and housing height.
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 achieves a compact and slim actuator design with reduced backlash and vibration, enhancing assembly efficiency and reducing costs while providing precise position control.
Implementation Method 1
a stator arranged on the bottom of the housing to rotate the rotor by generating a rotating magnetic field
Implementation Method 2
a first worm gear integrally formed on an outer circumferential portion of an extension unit extending to an upper portion of the rotor support
Data Source
AI summary
Provided is a drive motor having a slim BLDC motor vertically mounted in a housing and a swivel actuator using same. A swivel actuator includes: a cylindrical housing where a hollow cylindrical portion protrudes from a bottom of a center thereof and first and second step portions protrude from an inner side wall thereof; a drive motor arranged on the bottom surface of the housing and providing rotational power to a rotor support extending upward; a cylindrical first worm gear integrally formed on the outer circumference of the rotor support; and first and second three-stage gear mechanisms coupled to opposite outer circumferences of the first worm gear, and rotating a rotating table with increased torque by reducing a rotation speed of the first worm gear.