TAS Schäfer shrink discs create an external frictional connection between a shaft and a hollow shaft or hub. Axial actuation of conical components generates radial pressure, compressing the hub onto the shaft. The resulting shaft-hub interface transmits the load without backlash. The shrink disc supplies the clamping force; it does not itself carry the torque through the shaft-to-hub power path.
Torque-controlled clamping
The two-part design develops radial pressure through the axial movement of conical components. For torque-controlled sizes, the clamping screws are tightened progressively and evenly around the assembly until the specified screw torque is reached. This procedure allows fitting clearance to be taken up within the permitted design limits. The catalog torque rating applies to the correctly installed connection, so the final screw condition is part of the product specification.
Series overview
| Series | Designation |
|---|---|
| 3171 | Standard Series |
| 3181 | Strengthened Standard Series |
| 3191 | Heavy Series |
| 3193 | Strengthened Heavy Series |
Published product-group range
| Parameter | Published product-group range / characteristic |
|---|---|
| Transmittable torque | 36–3,356,000 Nm |
| Nominal diameter d | 14–660 mm |
| Clamping arrangement | External clamping; two-part construction |
| Assembly control | Specified clamping-screw tightening torque, subject to size-specific exceptions |
| Fit accommodation | Compensation for increased fitting clearance |
| Options | Different designs and special surface finishes |
The group ranges cover multiple constructions and sizes. The nominal diameter is the shrink-disc dimension, not an interchangeable description of the shaft diameter. Use the complete series and size designation to obtain the correct load capacity, outer diameter, width, clamping length, screw quantity and tightening values.
Important assembly distinction for the heavy ranges
The catalog identifies the TAS 31.. range as self-locking and generally controlled through the screw forces. It also states an exception for types 3191 and 3193 up to 185 mm: these use path control with the front faces flush. This size-dependent exception matters when preparing installation instructions. The product-group name must therefore be read together with the exact series and nominal size.
TAS 3171 construction and ordering details
| TAS 3171 Standard-Range characteristic | Catalog detail |
|---|---|
| d < 120 mm | Discs lightly oiled; without washers |
| d ≥ 120 mm | Discs painted; with washers |
| d ≥ 195 mm | Cone of bush not slit |
| Dimensions H and e | Stated in the unlocked position |
| Minimum yield strength Rp0.2 — solid shaft | 290 N/mm² |
| Minimum yield strength Rp0.2 — hub | 350 N/mm² |
| Ordering pattern | TAS 3171-d; example TAS 3171-200 |
The finish and washer arrangement in the TAS 3171 catalog change with nominal diameter. At d ≥ 195 mm, the listed bush cone is not slit. These details affect identification of the selected assembly and should be retained when comparing replacements. The minimum shaft and hub yield strengths listed above refer to the shown TAS 3171 catalog configuration; verify the materials and the connection calculation for the actual application.
Installation surfaces and lubrication
The shaft-to-hub contact surfaces must be clean, dry and free of grease. This requirement differs from the preparation of the shrink-disc functional surfaces and the interface between the hub and the shrink-disc bush or inner ring, which require the specified lubrication. Keep those surface requirements separate during preparation. The catalog identifies lubrication at screw threads and under screw heads; use the lubricant and procedure specified for the selected design.
Assembly, removal and access
Before tightening, confirm the shaft-hub fit, the position of the shrink disc and the required contact length. Apply the procedure for the actual series, including its specified tightening or path-control criterion. Because the two-part construction is self-locking, plan for the documented release arrangement and access to the relevant screws. A procedure from a non-self-locking three-part shrink disc should not be transferred directly to this construction.
Dimension and torque terminology
| Symbol | Meaning | Unit |
|---|---|---|
| d | Nominal diameter of the shrink disc | mm |
| d_w | Shaft diameter | mm |
| D | Outer diameter | mm |
| H | Shrink-disc width | mm |
| M_max | Maximum transmittable torque | Nm |
| M_A | Clamping-screw tightening torque | Nm |
| p_N | Average pressure applied to the hub | N/mm² |
| n_max | Permitted rotational frequency | min⁻¹ |
Do not confuse M_A, the clamping-screw tightening torque, with M_max, the maximum transmittable torque of the assembled shaft-hub connection. The bush and hub dimensions determine how the radial clamping load acts on the connection. A different shaft diameter or material can require a revised assessment even when the same nominal shrink-disc diameter appears suitable.
Applications and selection
Typical duties include hollow-shaft gearboxes, wind-power drives, raw-material handling, conveying, crushing and mixing equipment. Options include different constructions and special surface finishes. Select the finish according to the environment and verify that the exact design remains suitable for the machine load and assembly method.
Ordering information
Selection requires more than a nominal diameter and a torque value. Record the shaft diameter, hub outside diameter, clamping length, available axial and radial space, shaft and hub material properties, operating speed, load history and environmental conditions. Include simultaneous axial force, radial loading or bending where present so the complete connection can be assessed. Verify the selected size against its data sheet and installation instructions before specifying screw tightening or releasing the assembly.
Include the full type, nominal size, shaft and hub dimensions, materials, surface requirements and maintenance access in the enquiry. The catalog uses the pattern TAS 3171-d and gives TAS 3171-200 as an example. Confirm any reinforced or heavy-range alternative against its own data sheet.