Friction connections and locking assemblies

Our partner TAS Schäfer is a market leader in the production of mechanical and hydraulic friction-locked shaft-hub connections. In addition to mechanical shrink discs and clamping sets, the family-owned company is a global leader in the market for hydraulic shrink discs. The company's own state-of-the-art and certified production guarantees high-quality products. A customer-oriented, flexible and qualified team implements customer wishes quickly and professionally. Reliable technical advice from the design department is an essential component in this.

For optimum delivery capability, we keep all essential diameters in stock for our customers as raw material - forged blanks. Despite the high capital commitment, we decided to take this step in order to ensure optimum availability even for special drive elements.

Our frictional connections are considered state of the art. In particular, our various shrink disc models have long since established themselves in drive technology. They realise maximum energy density in the shaft-hub connection and are insensitive to shocks, impacts and corrosion. Therefore, they work absolutely reliably even under extreme conditions. Of course, we also recommend our range to you because we are convinced of its bandwidth. But if there is no perfect model for your individual application, we will optimise any shaft-hub unit using the latest design and calculation methods - until it meets your requirements 100%. Because customised solutions are our speciality.

All frictional connections are based on the same principle. In their simplest form, they consist of an inner and an outer ring with opposite conical surfaces. Axial displacement (mechanical or hydraulic) of the outer ring against the inner ring creates pressure. This causes the outer ring to expand outwards, while the inner ring is compressed inwards. The existing friction of the pressure occurring between the hub and the shaft means that a torque and/or an axial force can be transmitted. These depend on the coefficient of friction, the fit clearance, the clamping length and the shaft diameter.

Friction lock connections are versatile and can be used in almost all drive trains as well as in many other applications. Element sizes range from a few mm to more than 1,000 mm, with transmission torques from a few Nm to more than 18,000,000 Nm.

In a frictional connection, components are held together by static frictional forces in which they are axially braced against each other by conical friction surfaces. The radial pressure creates the bodies of the connection that are elastically braced in the direction of the shaft. The at least two bodies are moved axially against each other by screws, whereby the interference fit transmits ever greater radial forces through the surface pressure. The friction force generated opposes the displacement forces acting from the outside.

The special feature of the shaft-hub connection is the pure frictional connection. There does not have to be any weakening of the shafts to be connected in order to transmit the torque. Decisive for a reliable connection is the quality of the components used in terms of both material and workmanship. The connections are used wherever forces are to be introduced or torques transmitted and quick and easy assembly and disassembly are required. Friction connections can be found, among other things, in winches, various energy systems, in ship drives, in conveying and crushing technology in rolling mills and everywhere where torques have to be reliably transmitted.

A frictional shaft-hub connection from the field of mechanical engineering is also called a clamping set. In practice, you have to imagine that a machine element connects a hub, which can be a gear wheel, for example, with a shaft so that a torque and axial forces can be transmitted between these two elements without a form fit. At the same time, the hub is secured against axial displacement on the shaft.

A distinction can be made between self-centring and non-centring clamping sets. Self-centring clamping sets are able to centre a hub on a shaft with a high degree of accuracy and thus ensure correspondingly good concentricity. If non-centring clamping sets are used, a sufficiently long centring between a shaft and a hub is necessary, which should be at least twice as long as the width of the clamping set. The advantage of non-centring clamping sets is that they have the ability to compensate for larger differences in fit between a shaft and a hub.