The roller mill according to the invention substantially comprises at least one grinding roller and a grinding table, the grinding table having a grinding table inner space which is open in a downward direction, at least one grinding roller drive system for driving the grinding roller and a grinding table drive system for driving the grinding table. The grinding table drive system further has a gearless direct drive which is arranged in the grinding table inner space.
1. Roller mill having
a. at least one grinding roller,
b. a grinding table, the grinding table having a grinding table inner space which is open in a downward direction,
c. at least one grinding roller drive system for driving grinding table, such that the total installed drive power of the roller mill is divided over a plurality of drives, the roller mill characterized in that:
1) the grinding table drive system has a gearless direct drive which is arranged in the grinding table inner space,
2) the gearless direct drive has from 15% to 30% of the total installed drive power of the roller mill, and
3) the grinding table includes a lower portion that is constructed in a bell shaped or cylinder shaped manner, and the gearless direct drive is arranged inside the lower portion of the grinding table.
2. Roller mill according to claim 1 , characterised in that the grinding table has a grinding table support and the gearless direct drive has a rotor which is supported via the grinding table support.
3. Roller mill according to claim 2 , characterised in that the grinding table support is arranged on a base plate of the roller mill and the gearless direct drive has a stator which is supported on the base plate.
4. Roller mill according to claim 1 , characterised in that the gearless direct drive has a rotor which is connected to the grinding table in a rotationally secure manner.
5. Roller mill according to claim 1 , characterised in that the gearless direct drive is formed by a transverse flux motor.
6. Roller mill according to claim 1 , characterised in that the gearless direct drive is formed by a high torque motor having an inner stator and an outer rotor.
7. Roller mill according to claim 6 , the high torque motor having a rotor with permanent magnets.
8. Roller mill according to claim 1 , characterised in that the gearless direct drive is connected to an adjustment device for adjusting the direct drive to a predetermined drive torque.
9. Roller mill according to claim 1 , characterised in that the gearless direct drive is connected to an adjustment device which adjusts the direct drive to a predetermined proportion of the total power input of the roller mill.
10. Roller mill according to claim 1 , characterised in that there is provided for the grinding roller drive system an adjustment device which is also connected to the gearless direct drive and which adjusts it to a predetermined proportion of the total power input of the roller mill.
11. Roller mill according to claim 1 , characterised in that the gearless direct drive is connected to a frequency converter for the control thereof.
12. Roller mill according to claim 1 , characterised in that the gearless direct drive is directly connected to an electrical power supply network.