Membrane Disk Coupling for Belt Conveyor Drive Shaft Deformation
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Solution Overview
Problem
High-performance belt conveyors exceeding 4,000 kW face challenges in transmitting power due to deformation of the drive drum shaft under high belt tension, which conventional gear motor combinations and gearless drives struggle to compensate for, especially in large-scale opencast mining applications.
Innovation Solution
A novel displacement concept for the rotor of the slow-running electric motor, featuring a motor bearing on the motor side and a torsionally rigid coupling between the motor and drive drum, utilizing a membrane disk and screw connections to compensate for axial and deflection movements, ensuring both elasticity and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a gearless direct drive is used with high power (4,000 kW and more), then the need for reduction gears is eliminated, but the drive drum shaft deforms significantly under high belt tension and torque
Solution Approach 1:
The coupling is segmented into multiple functional components: a rigid part for torque transmission and a flexible membrane disk part for accommodating shaft deformations. This segmentation allows the coupling to simultaneously provide rigid torque transmission while compensating for shaft deflections caused by high belt tension and torque loads.
Solution Approach 2:
The membrane disk's physical parameters (thickness, material properties, geometry) are specifically designed to provide the required flexibility in axial and radial directions while maintaining torsional rigidity. By changing the parameters of the membrane disk, the coupling can accommodate shaft deformations without compromising torque transmission capability.
2Power
If the rotor is rigidly connected to the drive drum shaft, then torque transmission is efficient, but the air gap between rotor and stator varies excessively due to shaft deformations
Solution Approach 1:
The membrane disk coupling acts as an intermediary element between the rotor and drive drum shaft. It transmits torque from the shaft to the rotor while simultaneously compensating for shaft deformations, thereby maintaining a stable air gap. The coupling mediates between the rigid torque transmission requirement and the flexible accommodation of shaft movements.
Solution Approach 2:
The coupling incorporates dynamic flexibility through the membrane disk, which can adapt its deformation state in response to varying shaft positions and loads. This dynamic behavior allows the coupling to maintain optimal torque transmission while accommodating real-time changes in shaft alignment and air gap dimensions.
3Adaptability or versatility
If conventional elastic connections are used to compensate for shaft movements, then axial and radial deformations are accommodated, but torsional rigidity is insufficient for high torque applications
Solution Approach 1:
The coupling exhibits different mechanical properties in different directions: it is flexible in axial and radial directions to accommodate shaft movements, but torsionally rigid to transmit high torques. This local differentiation of mechanical properties is achieved through the specific geometry and material characteristics of the membrane disk, which provides directional flexibility and rigidity as required.
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 effectively compensates for significant deformations and high torques in high-performance belt conveyors, eliminating the need for reduction gears and providing a reliable connection suitable for high-torque applications.
Implementation Method 1
Flange and support disk have threads, which are used to fasten a membrane disk on both sides with screws. The properties of the steel of the membrane disc, the width of its deformable ring and its thickness determine the properties of the membrane action. They are adapted to the respective operating conditions, so that the relative movements between the output shaft of the electric motor and the drive shaft of the drive drum can be compensated for both in the axial direction and the deflection of both shafts by compensating movements.
Data Source
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AI summary
The invention relates to the arrangement and design of a connection between a gearless drive and the drive drum of a belt conveyor. Such a solution is particularly suitable for belt conveyors subjected to extremely high operating loads. To reduce deformation of the drive shaft, the rotor is supported on the side facing away from the drive drum by a motor bearing. The connection between the rotor (1) and the drive drum is provided by a novel coupling that can compensate for the deformation of the drum shaft (2). For such a coupling, the output shaft of the drive and the axially arranged drive shaft (2) of the drive drum are each designed as flanges (7, 9) with different outer diameters. Both flanges (7, 9) are connected to each other by means of screw connections via an annular diaphragm (8).A coupling designed in this way is able to compensate for relative movements of the motor output shaft and the drive shaft (2) of the drive drum both in the axial direction and in the deflection of both shafts (1, 2).