High-torque motor eliminates couplings

At the EMO 2001 show in Hanover in September, Siemens is unveiling a permanent magnet, synchronous motor for three-phase machine tool drives that can deliver torque values of up to 4,100Nm.

The high level of torque is produced using a fixed stator that transmits the torque directly to the rotor via the airgap, in a similar way to a linear motor. Siemens says that this approach results in a wear- and maintenance-free drive that eliminates the need for inaccurate mechanical transmission elements.

The torque motors are said to offer high levels of precision and dynamics and can be used both for positioning and for continuous path control involving the interpolation of several dynamic axes. Siemens suggests that the motors will be particularly suitable for machine tools with rotary tables or swiveling axes, such as in high-speed cutting centres, or profile milling systems with swiveling heads. They can also be used on quick run-up axes on turning machines, for tool magazines in machining centres, for robot applications, and in injection moulding machines.

The motors will be available with an external cooling jacket, or in a precision version which uses a built-in cooler to produce a precise temperature profile. The motors can also be used without cooling although this reduces their constant torque abilities.