Shaft-hub connections play an important role in drive technology. They are the connecting element between the shaft and the machine elements mounted on the shaft, such as a gear or pulley. The main function is to transmit torque and power. Shaft-hub connections are divided into three groups: positive-locking, friction-locking, material-locking shaft-hub connections and combinations thereof.
In the case of the positive shaft-hub connection, the components are produced by appropriately shaped elements such as a splined shaft or another component such as a key. Power and torque are transmitted via surface pressure.
In case of frictional shaft-hub connections, the components are clamped against each other by means of clamping screws and clamping elements. Power and torque are transmitted by the frictional force.
In case of material-fit shaft-hub connections, the connection is made by gluing, soldering or welding. This type of connection is used rather rarely.
The areas of application for shaft-hub connections are numerous and range from the manufacture of motors and gearboxes to machine tools, printing machines, paper machines, packaging machines, foodstuffs machines, wind power plants, materials handling technology, vehicle technology and railroad technology. In short, they are indispensable in drive technology.
Our ASK shaft-hub connections are friction-locked connections, so-called cone clamping elements. Both cone clamping elements and shrink discs can transmit higher torques compared to positive shaft-hub connections with feather keys. The shaft is pushed through the bore and the hub over the outer diameter of the shaft-hub connection. By tightening the bolts, the shaft-hub connection is pressed against the hub via the conical shape. A frictional connection is created. Compared to positive connections, non-positive connections have the following advantages:
- HIGHER TRANSMITTABLE TORQUES (FORCES)
- VERY GOOD CONCENTRICITY DUE TO AVOIDANCE OF IMBALANCES
- SELF-CENTERING
- FREE OF PLAY
- EASY ASSEMBLY AND DISASSEMBLY
- NO ADDITIONAL MACHINING OF THE SHAFT NECESSARY (ADDITIONAL ELEMENTS SUCH AS FEATHER KEYS ARE NOT REQUIRED)
- VERY LOW NOTCH EFFECT
Technical basics shaft-hub-connections
ASK shaft-hub connections are machine elements with which hubs can be fastened to shafts. The forces and torques are transmitted non-positively. The connections are detachable and can transmit axial forces and torques. The required clamping force is generated by axial displacement of conical rings in the gap between shaft and hub.
The amount of forces that can be transmitted depends, among other things, on the permissible surface pressure, the coefficient of friction and the tightening torque of the clamping screws.
CONSTRUCTION TYPES
ASK 110 ASK 130 ASK 131 ASK 132
ASK 133 ASK 134 ASK 200 ASK 300
The difference between the designs is the contact surface for the hub (ASK 131, 133 and 134) and the required size of the annular gap between the shaft and hub. The forces / torques that can be transmitted depend on the friction surface, the number and size of the clamping screws.
LAYOUT
In the data sheets, the tightening torques of the bolts and the resulting maximum axial force or maximum transmissible torque are specified for each connection.
The values given are calculated from the surface pressure resulting from the bolt pretension. These in combination with the friction values result in a maximum force that can be transmitted. The maximum axial force can only be transmitted if the torque = 0 and the maximum torque only if the axial force = 0.
For combinations of axial force and torque, the resulting force must be calculated; it must be smaller than the maximum transmissible frictional force. This results from the surface pressure and the friction values.
The specifications for the maximum axial force or torque apply to ideal conditions.
In operation, the forces must be significantly lower. Among other things, the following operating conditions must be taken into account by means of appropriate safety margins:
- Starting torques
- Shocks
- Shocks Vibrations
- Settling / Smoothing of the surface
- alternating load direction
The pretensioning force of the screws may decrease due to settling. In any case, it is recommended to check the tightening torques regularly.