External Direct Drive Motor for Compact Roller Conveyor
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Solution Overview
Problem
Commercially available motorized rollers are too large and heavy for narrow conveyors, and their reliability is limited due to gear failure, making them unsuitable for small packages and requiring frequent maintenance.
Innovation Solution
A compact, externally mounted, low-voltage, brushless DC motor with a large diameter and short axial length drives the rollers directly, eliminating the need for a gearbox and using elastomeric drive belts to connect the motor to the rollers, reducing noise and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If motorized rollers are made compact to fit narrow conveyors, then the conveyor space utilization is improved, but the reliability deteriorates due to gear failure in small-scale mechanisms
Solution Approach 1:
The motorized roller is divided into separate modular components: the drive mechanism is separated from the roller itself, allowing the roller to be compact while the drive mechanism can be positioned externally or in a dedicated space. This segmentation enables compact roller design without compromising drive mechanism reliability.
Solution Approach 2:
The drive mechanism is repositioned from an internal axial stacking arrangement to an external or side-mounted configuration. This dimensional change allows the roller to maintain a compact form factor while the drive mechanism operates from a different spatial plane, avoiding the reliability issues of miniaturized internal gears.
2Device complexity
If motorized rollers are designed with internal drive mechanisms, then the integration is improved, but the minimum length increases to 28cm preventing use in narrow conveyors
Solution Approach 1:
The integrated motorized roller is segmented into a compact roller unit and a separate drive unit. The drive unit can be mounted externally on the conveyor frame or on select rollers, allowing the main roller body to be shortened to fit narrow conveyor spaces while maintaining functional integration through the separate drive mechanism.
Solution Approach 2:
An intermediary drive mechanism is introduced that can be positioned between the motor and the roller, or mounted on the conveyor frame rather than integrated within the roller. This intermediary approach allows the roller length to be reduced while the drive function is maintained through the intermediary positioning.
3Power
If gear reducers are used in motorized rollers, then the torque control is improved, but the maintenance requirements increase due to gear failure
Solution Approach 1:
The gear reducer is extracted from the internal roller structure and positioned externally or integrated into the motor assembly separately. This extraction eliminates the need for maintenance of internal gears within the roller, as the drive mechanism can be accessed, serviced, or replaced independently without disassembling the roller itself.
Solution Approach 2:
The mechanical gear reduction system is replaced with an alternative mechanism such as a direct-drive motor with electronic torque control, or a belt-driven system that requires less maintenance. This substitution eliminates or reduces the maintenance burden associated with traditional gear reducers while maintaining torque control capability.
4Use of energy by moving object
If traditional motorized rollers are used, then the power consumption is reduced compared to AC motors, but the noise generation remains an issue
Solution Approach 1:
The mechanical gear transmission system is replaced with a direct-drive configuration or belt-driven system that eliminates gear meshing noise. This substitution maintains the low power consumption advantage of DC motors while significantly reducing noise generation by removing the primary noise source (gear engagement).
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 solution allows for smaller, more reliable rollers with reduced maintenance needs, improved efficiency, and increased reliability, enabling the use of motorized rollers in narrower spaces and with smaller packages while minimizing mechanical losses and gear-related issues.
Implementation Method 1
elastomeric drive belts to connect the motor to the rollers
Implementation Method 2
elastomeric drive belts to connect the motor to the rollers
Data Source
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AI summary
A conveyor that is powered by a drive unit is disclosed. The conveyor includes a frame (16), and the drive unit includes a gearless external drive motor (20) that is configured to fit within the footprint defined by the conveyor frame. The conveyor includes a series of conveying members, such as rollers (18), that are rotatably supported by the frame. The motor includes an output member that is engaged with a driven one of the rollers, and the driven roller is mechanically linked to an adjacent one of the rollers so that the adjacent roller is driven into rotation in response to rotation of the driven roller. The conveyor is constructed as a conveyor section or zone, which is adapted to be used with a series of similarly constructed conveyor sections or zones to form an overall conveyor system.