Keyless element works based on wedge friction theory. By tightening clamping screw, clamp force generated. Due to taper geometry, clamp force is transmitted in radial direction to other member which induced contact pressure on hub and shaft. Due to interference between two bonded parts at shaft and hub, torque can be transmitted from shaft to hub through keyless elements.
Keyless transmission elements which have varied and versatile applications on almost all engineering fields.The elements have great absorbing capacity of kinetic energy by elastic radial deformation of tapered rings. The method is also very simple. By expansion of the outer ring & shrinkage of inner rings, frictional shaft & hub connections are established, which transmits highest torques free from backlash.
Drawbacks Of KEY
Though apparently seems simple but preparing keyway is one of the difficult machining operations:
Increase in cost due to various operation involved – setting & down time + machining time,
Lateral shifting of Keyways: in process it is extremely difficult to set the centre line of the keyway exactly symmetrical and parallel with respect to the radial plane,
Heavy torsional stresses are concentrated at the corner of the keyway so shaft is weakened,
Deviation in keyway width,
Not parallel to the axis
The cumulative effect of the all above (operational) errors, is really calls for an alternative system-keyless Transmission.
NMTG Keyless Transmission Elements Entirely eliminates drawbacks of key transmission and conventional shrink connections and also involved calculations, extremely close machining tolerances - creating problems while fitting & removing parts and during repair work - adjustment, exchanging, etc. It efficiently replaces, key & polygon connections, splined shafts, etc.
Benefits of KTE
Keyless elements are most suitable for securing all types of bosses and hubs on shafts and axles:
No Keyway, No extra machining, No notch effect,
Perfect true running,
Easy adjustability / Easy exchangeability,
Need no stops,
Easy mounting : Elements are tightened using standard screws and standard tools. Extra machining or fitting work is not required,
Easy removal : provision of release tapped - saving much time, the double tapers prevent self-locking and ensures the the element can be released without difficulty,
Freedom from wear - having no moving parts,
Overload protection effect - When the permissible load is exceeded, elements will slip
In this way, they can safeguard valuable machine components against damage. However the slip causes fretting of the contact surfaces, so elements should not be used as slip clutch.