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.
Displacement-controlled assembly
The two-part displacement-controlled design uses axial movement of the pressure ring and bush to generate radial clamping pressure. The catalog describes the TAS 33.. construction as self-locking. Its defined assembly condition is reached when the relevant front faces are flush. This distinguishes the installation criterion from a connection that is controlled only by achieving a screw tightening torque.
Series overview
| Series | Designation | Position in the product family |
|---|---|---|
| 3173 | Mini Series | Compact displacement-controlled design |
| 3371 | Standard Series | Standard displacement-controlled range |
| 3381 | Strengthened Standard Series | Strengthened standard-range version |
| 3391 | Heavy Series | Heavy-range version |
| 3393 | Strengthened Heavy Series | Strengthened heavy-range version |
Published product-group range
| Parameter | Published product-group range / characteristic |
|---|---|
| Transmittable torque | 150–14,730,000 Nm |
| Nominal diameter d | 24–950 mm |
| Clamping arrangement | External clamping; two-part construction |
| Assembly control | Specified axial displacement; front faces flush |
| Product-group features | Reduced weight and suitability for low application temperatures |
| Size-specific limits | Use the selected series and size data sheet |
The diameter and torque figures describe the complete product group. They do not imply that every series covers the entire diameter interval, or that the maximum torque is available at every size. Nominal diameter d identifies the shrink disc and must be distinguished from shaft diameter d_w. A final selection needs both the shrink-disc geometry and the actual shaft-hub arrangement.
Installation and handling
The assembly process places the shrink disc on the hollow shaft and progressively actuates the conical components with the clamping screws. Use the prescribed sequence and displacement criterion for the actual size. Do not substitute the torque-control procedure of a different product family. The self-locking construction also makes the selected release procedure relevant when planning maintenance access and the available space around the connection.
Surface preparation
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.
TAS 3173 Mini-Range construction details
| TAS 3173 Mini-Range characteristic | Catalog detail |
|---|---|
| Finish | Discs and bush galvanized |
| Washers | Without washers |
| Bush | Completely 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 3173-d; example TAS 3173-100 |
The Mini-Range details above apply specifically to TAS 3173. The listed material values are minimum yield-strength requirements for the shaft and hub in that catalog configuration. They should be checked against the actual material certification and any application calculation. Similarly, dimensions marked in the unlocked position must be interpreted in that condition when evaluating space and installation clearances.
Interpreting dimensions and ratings
| 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 |
Maximum transmittable torque M_max and clamping-screw tightening torque M_A are different quantities. The former concerns the capability of the assembled connection; the latter is an installation value where specified. Width H, outer diameter D, bush length and axial excess length affect the machine envelope. The permitted rotational frequency and pressure applied to the hub also require a size-specific check.
Applications
The family is used for backlash-free connections on hollow-shaft gearboxes and industrial drive systems. Listed application areas include wind power, raw-material extraction, conveying, crushing, mixing and process technology. The displacement criterion can be useful where observing the required assembly position is more practical than controlling an installation entirely through a torque wrench. The product group is also described as suitable for low application temperatures; confirm the actual temperature limits for the selected material, lubricant and configuration.
Selection and ordering
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.
Specify the required series and nominal diameter together with the shaft diameter and hub geometry. The catalog gives an ordering pattern such as TAS 3173-d, with TAS 3173-100 as an example. Preserve the complete series number because standard, strengthened and heavy-range constructions are separate selections.