ZF has pooled its comprehensive knowhow for the new hollow shaft drives from the Duoplan model range. Consequently, the ZF-Duoplan 2K 150 HS that was already presented in 2012 features a top speed of 18,000 revolutions per minute with up to 24 kilowatt (kW) drives with 600 newton meters (Nm) of nominal output torque. Now, two further versions for higher performance ranges are almost ready for the start of production at ZF: The 2K 280 HS/HWG is predestined for up to 44 kW or 1,400 Nm and, thus, scores with a maximum of 16,000 revolutions. In addition, there is the 2K 380 HS/HWG that excels with up to 12,500 revolutions with 60 kW motors or 1,900 Nm engines.
The special features of the ZF hollow shaft drives can be attributed to the innovative design for which there is a patent pending: The extremely compact planetary gear set is only active when it is actually required. In the event of high speeds in direct drive (gear ratio 1:1), it remains decoupled which drastically reduces the rotating masses. The resulting advantages over conventional planet or spur gear drives go far beyond high rotation speeds: They range from the short ramp-up times to the excellent efficiency and the low temperature level of a maximum of 37 degrees to vibration values that always remain below one millimeter per second.
The ZF hollow shaft drives increase the spread between the torque and the speed for machine tools, irrespective of whether they are operated with a DC or AC drive. In doing so, the new Duoplan variants increase the bandwidth of possible applications and consequently improve the workload of each machine. Furthermore, they can be vertically or horizontally docked in a direct manner to highly dynamic spindle motors in a flange design that enable shorter cycle times. For the first time, the ZF two-speed drives are therefore also an option for machines that were previously only suitable for direct drives. A further advantage: The hollow shaft design allows pushrods for release units or even coolants to be passed through the drive. As it is the case with all other products from the Duoplan family, these innovations are also maintenance-free and particularly durable.
The new Duoplan 2K 450 and 2K 600 two-speed manual transmissions now complete ZF's product range. The transmissions that can be delivered as of now are designed for nominal input torques of 450 or 600 Nm and thus complete the 2K series which already covers torques up to 300 and over 800 Nm.
ZF now offers more than ten different transmission variants for several applications and installation positions with the expanded product range. With their help, motors with installation dimensions of 100 to 280 millimeters axle height can be operated; the range of the transferred power is between 19 and 120 kW, the range of the nominal input torques is between 120 and 1,200 Nm.
For mechanical engineering companies, this extensive range of transmissions offers the advantage to further increase their efficiency and their cost-effectiveness, because an optimally adjusted motor/transmission unit also reduces energy consumption.
In addition, there are the proven advantages of the shiftable two-speed transmission: If hard materials are to be machined, the ZF Duoplan 2K transmissions transfer high torques at low rotational speeds. If soft materials must be processed, the ZF machine drives supply high speeds in the upper speed range. These and many more innovations will be on-hand as ZF displays its products and technologies at Booth E-4868 in the Motion, Drive and Automation show taking place at IMTS 2014 in Chicago.