TAS Schäfer lists an FK configuration for connections with a large difference between shaft diameters. The catalog explains that matching shaft sizes are generally the initial target, while adapted flange hubs and different shrink discs can accommodate unequal shaft ends. This allows the connection to be developed around the actual machine interfaces.
Connection principle and load path
TAS Schäfer rigid flange couplings connect shaft ends through backlash-free frictional shaft-hub connections. Each shrink disc supplies the radial clamping force that presses a flange hub onto its shaft. Torque passes through the shaft-to-flange friction interface and the bolted flange connection; the shrink disc itself is outside that load path. The flange connection can be separated directly at the mating faces, which supports assembly and maintenance of the drive.
Configuration and identification
| Configuration item | Details |
|---|---|
| Configuration | FK with a large difference in shaft diameter |
| Design method | Adapted flange hubs with appropriate shrink discs |
| Shaft identification | Specify d_w1 and d_w2 separately |
| Load assessment | Check each shrink connection and the flange joint |
| Dimensional basis | Application-specific coupling drawing |
| Ordering requirement | Both shaft dimensions, tolerances, materials and loads |
Adapting the two shaft connections
Each flange hub must suit its own shaft diameter and clamping requirements while remaining compatible with the mating flange joint. The appropriate shrink disc and tightening condition may differ between sides. Check the smaller shaft, the larger hub, material strength, contact pressure and the flange bolting rather than assigning the entire assembly the rating of one standard shrink disc.
Published product-group range
| Characteristic | Published flange-coupling product-group information |
|---|---|
| Transmittable torque | 830–2,742,000 Nm across the product group |
| Nominal diameter | 38–500 mm across the product group |
| Load duties | Torque and dynamic loads; assess axial force and bending where present |
| Connection | Rigid, backlash-free frictional shaft-hub connection |
| Special options | Application-specific designs and corrosion protection |
| Range interpretation | Confirm the actual series, size and configuration rating |
The published group range covers several sizes and constructions. It does not mean that every nominal size or special configuration achieves the maximum listed torque. Brake-disc options, half couplings, different shaft diameters and adapted hubs require the values for their exact assembly.
Drawing and torque terminology
| Symbol | Meaning |
|---|---|
| d_w1 / d_w2 | Shaft diameters at flange sides 1 and 2 |
| M_t,max | Maximum transmittable torque for the specified connection |
| A / D / D_z | Pitch-circle diameter / outer diameter / flange-centering diameter |
| L / a / b / z | Coupling width / shrink-disc width / flange thickness / centering depth |
| Z / S / M_A | Bolt quantity / bolt size / required tightening torque |
| I | Mass moment of inertia |
The tightening values for the shrink-disc screws and for the flange bolts belong to separate fastener groups. Use the actual size-specific value for each. Mass moment of inertia I is expressed in kgm², while weight is listed in kg; these are different selection parameters.
Surface preparation and assembly
Keep the shaft-to-hub contact surfaces and the mating flange faces clean, dry and free of grease. This differs from the functional surfaces of the shrink disc, its screw threads and under-head bearing surfaces, which require the specified lubricant. The flange-hub-to-shrink-disc contact surfaces are oiled as described in the installation documentation. Mixing these surface-preparation requirements can change the intended friction conditions.
Combined loads and operating conditions
Check the shrink connection and the flange bolting separately. Torque, bending moment and axial force may act together at the shaft-hub interface, while the flange bolts and flange body must also be assessed for their actual load. A static torque check alone does not cover cyclic bending or other dynamic duties. Provide the load spectrum and operating speed so the complete assembly can be evaluated.
Configuration and ordering example
The general ordering example TAS FK-090/085/095 illustrates separate identification of two shaft diameters. A large-difference configuration requires its own approved design, so this example is a coding illustration rather than a rating for every unequal-shaft connection. Provide both shaft drawings, the available space and the expected combined loads when preparing an enquiry.
Application information
Listed application areas include marine drives, wind-power equipment, conveying systems, mixing and process machinery, hydropower, crushing plants and elevators. The appropriate configuration depends on the machine interface and operating duty. Special corrosion protection and individual designs can be specified, and hydraulic shrink-disc arrangements are also available as a separately defined configuration.
Selection and ordering
Specify the complete coupling type, nominal size, both shaft diameters, shaft tolerances, material properties, speed, torque and any axial or bending loads. Include available space, tool access, assembly sequence, surface protection and maintenance requirements. Confirm the type-specific drawing and the required screw tightening values before finalizing the selection.