Torsionally Rigid Flexible Coupling Torque Transmission
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Solution Overview
Problem
Conventional torsionally rigid flexible shaft couplings face limitations in transmitting high torque while maintaining sufficient misalignment capabilities, leading to increased bending torques that can cause disengagement and potential fractures under dynamic loads, and result in frictional corrosion and slip.
Innovation Solution
The solution involves reducing misalignment by 50% to 75% to minimize clearances, using high-strength heat-treated steel flanged sleeves with increased surface friction through abrasive blasting or coating, and thicker plates to enhance stiffness and torque transmission, while maintaining the same bolt dimensions and radiussed geometry for easy replacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If sufficient clearances are provided between plate packs and hub to accommodate misalignment, then misalignment capability is improved, but torque transmission capability deteriorates due to reduced stiffness and increased bending torques
Solution Approach 1:
The patent changes the clearance parameter from conventional large clearances (ratio 1:40 or smaller) to reduced clearances (ratio 1:60 to 1:100), thereby increasing stiffness and torque transmission capability while still accommodating misalignment through the flexible plate pack design
Solution Approach 2:
The patent introduces radiussed engagement surfaces with specific radius ratios (r1/d = 0.05 to 0.15, r2/d = 0.02 to 0.05) to reduce stress concentration and bending torques, allowing for reduced clearances without compromising misalignment capability
2Adaptability or versatility
If high bending torques are transmitted through flanged sleeves and bolts to accommodate misalignment, then misalignment capability is improved, but reliability deteriorates due to potential fracture of bolts or sleeves
Solution Approach 1:
The patent reduces the lever arm parameter (distance between hub face and plate pack) by reducing clearances, thereby directly reducing the bending torque parameter acting on flanged sleeves and bolts, eliminating the risk of fracture
Solution Approach 2:
The radiussed engagement surfaces distribute the bending loads more evenly across the contact area, reducing stress concentration points and preventing localized failure of bolts and sleeves
3Ease of operation
If low coefficient of friction is present between flanged sleeve and hub, then ease of assembly is improved, but torque transmission capability deteriorates due to slip and frictional corrosion
Solution Approach 1:
The patent changes the friction coefficient parameter from conventional low values (0.1) to enhanced values (0.3 or higher) through surface treatment, thereby increasing the frictional torque transmission capability and preventing slip and frictional corrosion
Solution Approach 2:
The patent applies surface treatment (abrasive blasting or coating) locally to the engagement surfaces of the flanged sleeve, creating high-friction zones only where needed for torque transmission while maintaining ease of assembly
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 approach increases torque transmission by a factor of 1.8 to 2, reduces bending torque, and minimizes micromovements, thereby preventing fractures and frictional corrosion, while allowing for efficient power density with reduced flange clearance.
Implementation Method 1
At a coefficient of friction equal to 0.1 between flanged sleeve 6 and hub 1, the torque acting between the sleeve and the hub is transmitted via combined frictional and positive (i.e. shape-locked) engagement
Implementation Method 2
The surface roughening may be obtained by abrasive blasting (e.g. sand blasting) or by coating (e.g. Durni Disp SiC or Ekagrip)
Data Source
AI summary
A torsionally rigid flexible shaft coupling, in particular, fully-steel shaft coupling, for transmitting torques between shafts, in particular shafts with axes which are offset relative to one another, having one or two plate packs (5) which are placed on flange sleeves (6) and on the latter, are clamped by means of a ring (4) against an end-side flange (65b) of the flange sleeve (6), wherein the plate packs are clamped in an alternating fashion in the peripheral direction to the sleeves (8) or second hubs (9), which face one another, by means of screws (7) which extend through the flange sleeves (6) and have nuts (2). In order to considerably increase the torque which can be transmitted, it is provided that the flange sleeve (14) is shorter in the axial direction than the known flange sleeves, and that, in order to increase the torque component which can be transmitted in a frictionally locking manner, the flange sleeve is rounded in a chamfered manner, and contains a coated radius geometry (6e), in its transition region to the planar face of the hub (1).