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Miki Pulley Step-Flex and Jaw Spider Couplings


Miki Pulley have an excellent reputation for producing high quality products such as their speed chargers and electromagnetic clutches. They are also expert coupling manufacturers and here we will take a closer look at a couple of their innovative products.

Miki Pulley Step-Flex Couplings

The Miki components known as Step-Flex couplings are designed to improve ball screw performance while simultaneously reducing problems caused by vibration and resonance. The Step-Flex is a particularly innovative type of shaft coupling, with its construction featuring a combination of two elastomer elements.

The elastomer elements help dampen vibration caused by the actuator carrier, which usually occurs when there is some misalignment and the carrier is forced to make multiple minor adjustments in quick succession in order to find its ‘home’ position.

Miki Pulley design the Step-Flex coupling with one harder element, usually coloured black, that is separated from the aluminium alloy hubs by the softer elastomer disc, usually coloured green. The torsional stiffness is then maintained for optimum performance and positional accuracy while minimal angular and parallel misalignments can be easily tolerated and subsequent vibrations absorbed.

The power-transmitting element features different layers of hardness and also helps reduces the counter force generated by misalignment. The heat load is then minimised during operation thanks to the overall load on the bearing being reduced.

Another benefit of the elastomer elements for rotary motion applications is the electric and temperature isolation which lessens the conductive heat that inevitably transfers from the motor to the connected output shaft. The elastomer also prevents stray voltage transmitting along the shaft.

The Miki Step-Flex coupling remains one of the most popular Miki components and is available in nine sizes ranging from 3mm to 30mm.

Miki Components: ALS Coupling (Jaw Spider)

The ALS couplings are power transmission couplings that are able to transmit torque via two shafts while damping vibrations and accommodating any misalignment.

The design of these Miki Pulley couplings feature a polyurethane elastomer element called a ‘spider’ which sits between two aluminium hubs which decrease moments of inertia caused when the application starts and stops. Torsional stiffness is maintained by the spider element keeping the aluminium hubs separate which also enhances the positional accuracy. This design also accommodates minimal angular and parallel misalignment and absorbs impacts and vibrations, dissipating heat in the process.

The three components of the coupling are assembled together with a jaw from each hub fitting snug with the ‘legs’ of the spider element, with each spider leg having a slight curve which enables pre-compression without backlash. The ALS elastomer spider elements can come with various hardness values according to the requirements of the application. The hubs are also clamped easily onto both connecting shafts, locking the coupling in position with recessed tightening screws.

Different hub-types are available too, such as keyed-style and pilot bore. Overall there are eight models of the ALS coupling with a bore size range between 3mm and 60mm.

If you require any Miki components such as the Step-Flex coupling or any of their speed chargers and electromagnetic clutches, then contact YB Components who are the UK’s leading couplings suppliers.