Target of a flexible shaft is to transmit rotary power or torque. The application of flexible shaft is, it is connected between drive and driven to transmit rotary power where straight line transmission is not possible, or there is a small misalignment between drive and driven elements. The flexible shaft transmission is also utilised to transmit rotary power in hazardous locations or in hot environments where direct handling of driven element is not possible, e.g., hot environments of steel production or in clean room applications. For different applications, special flexible shafts can be designed to meet the requirement at its best. For the design of a flexible shaft it is important to know the torque to be transmitted, the bending radius of the shaft, the maximum RPM required, the environment in which the flexible shaft has to run, the preferred turning direction and the length required.
In the flexible shaft design, the parameters torque, minimum radius, speed and torsion deflection are interdependent and cannot be varied independently. For example, if more torque is required, the minimum radius increases and torsion deflection reduces. The flexible shaft is designed for the required specification by deciding on number of layers, the number of wires per layer, the diameter of the wire, the material of the wire, tensile strength and type of plating.
In the picture, one can see torsion shaft, speedometer shaft and hollow shaft. This indicates the various layers, number of wires in each layer and the direction of lay.
Materials such as high speed spring steel, spring steel coated with the brass, rolled steel of galvanised or non-galvanised with varying diameters are maintained. Coated brass of spring steel is used on the top most layer (one wire) as identification for the Suhner products of flexible shafts, which is also called Tiger Mark. The applications of flexible shaft, are vast. Some of them, to mention a few, are driving speedometers, counters, automotive seat adjustments, window filters, for opening and closing sunroofs and many more. And in case of high speed rotary cores a protective casing is recommended for safety, ability to hold shaft while running, smooth operation and for shock absorption.
The Suhner group is specialised in flexible shaft design and manufacturing and has today more than 100 years experience with the product design and manufacturing equipment.
(Suhner India Pvt Ltd, Bangalore. Tel: 080-27831108. Fax: 91-80-27831109. Email: blroffice.in@suhner.com, transmission.in@suhner.com) |
