Rieter

Drives

Index

Of the various drives in an automated ring spinning machine, those for the rotors, the opening rollers and spinning vacuum account for the majority of energy consumption. Fig. 38 shows the proportion of energy consumed by the main drives of a rotor spinning machine.

The rotors and opening rollers are usually driven by tangential belts, with a growing trend toward synchronous drives. Individual drives provide advantages in flexibility, but entail high costs and very complex controls. Major aspects when considering drives are smooth running, the cost factor and energy consumption.

The settings for draft (ratio nfeedcylinder/ ndeliverycylinder), yarn twist (ratio nrotorspeed /ndeliverycylinder) and winding tension (ratio ndeliverycylinder/nwindingshaft) are made via the drives for the feed cylinder, the take-off rollers and the winding shaft. The interaction of the drives for draft, twist and winding tension is shown schematically in Fig. 39. Settings are made either via infinitely adjustable inverter drives or conventionally via change gears.

The use of infinitely adjustable inverter drives reduces both operator effort when changing setting parameters and machine downtimes, since gear wheels no longer have to be changed with this concept. The settings for draft, yarn twist and tension can be individually entered directly at the machine control panel, as can the values for rotor and opening roller speed (optional in some cases) with inverter drives.

The package conveyor belts (one conveyor belt on each side of the machine) are driven from the tailstock. The package conveyor belt starts automatically when a preset number of completed packages have been placed on the belt. The conveyor belt transports the packages to the end of the machine, where the packages are ready for removal. When all packages have been removed the package conveyor belt drive is switched off. Various concepts are offered for package doffing (refer to section  Package transport between the rotor spinning machine and subsequent zones).

Empty tubes are transported (to the operating robot) by narrow conveyor belts arranged in pairs (Fig. 40), which are driven by a separate motor. Each side of the machine is equipped with a pair of belts operating independently of each other. The package handling system of the tube magazine places an empty tube on each of the pair of conveyor belts. As soon as the spinning robot requests an empty tube, the conveyor belt starts and delivers the empty tube to the robot‘s empty tube holder.

The drives for the trash conveyor belt (one on each side of the machine) are designed so that the belts are moved alternately forward and backward (Fig. 41). The reversal point is controlled by a sensor. Suction units which extract the trash removed from the  spinning box and transport it to the central filter are located at the reversal points.

Power for all control units is supplied by an externally driven motor via a generator. The motor and generator are in the headstock. The flywheel mass of the three-phase motor generates enough power to bridge short-term power failures lasting a few seconds, without causing the machine to shut down.

Fig. 38 – Breakdown of energy consumption for the various drives of a rotor spinning machine

Fig. 39 – Infinitely adjustable inverter drives for draft, twist and winding tension

Fig. 40 – Supplying empty tubes via conveyor belts

Fig. 41 – Trash removal belt with suction units