Simplify the assembly of torque motors

Ringspann offers a wide range of shaft-hub connections of different types for frictionally engaged power transmission in the drive trains of machines and systems. The clamping systems of the RTM family play a special role here. They are specially designed for the safe and precise assembly of torque motors on solid and hollow shafts. Their particular strengths include backlash-free and torsionally stiff torque transmission, excellent concentricity and a design that takes into account the design specifications of leading motor manufacturers.

Torque motors belong to the group of electric servomotors and have proven themselves today as high-torque direct drives in many applications in mechanical and plant engineering. They have proven to be particularly advantageous in the design of gearless drive systems that have to flexibly implement high dynamic requirements at rather low speeds. Concrete fields of application are, for example, extruders in plastics technology, film stretching machines, slitter rewinders in paper processing, rotary indexing tables in machine tool and assembly technology, the lifting units of powerful servo presses as well as numerous automation applications. In order to enable machine and system manufacturers to easily integrate modern complete and built-in torque motors into their drive systems, Ringspann now offers four friction clamping systems. They are combined in the RTM series and are all suitable for fastening and simultaneously centring torque motors on shafts and hollow shafts. Their advantages include backlash-free, torsionally stiff transmission of the torque exerted by the motor, high concentricity and application-compliant loading of the connection components. "Depending on the version, they also provide support for the torque motor in addition to the mechanical connection and centring and are designed for the standard motors of leading manufacturers. In addition, they are easy to install thanks to their clever design and reduce the maintenance effort," says RINGSPANN product manager Marvin Raquet.

Optimised for Siemens motors

The RTM 601 clamping system from Ringspann is specifically designed for mounting compact built-in torque motors. It consists of a flanged taper ring and a taper ring. They are frictionally fixed to the shaft with clamping screws and transmit the torque generated by the motor into the machine shaft without backlash or loss. Both the maximum transmittable torque and the shaft diameter can be adapted to the customer or project. The design of the more complex RTM 607 clamping system, which is tailor-made for fastening, supporting and centring the widely used 1FW3 complete torque motors from Siemens, is similar. It consists of a steel cone clamping element and a centring bush with aluminium flange. The clamping element ensures the transmission of the motor torque to the machine shaft and centres the torque motor on the drive side. The centring bush also supports the optimal alignment of the motor to the machine shaft. Rods and a retaining ring fix its axial position. The RTM 607 from Ringspann can be customised with regard to shaft diameters in a range of approximately 60 to 125 mm.

"Flying" centring possible

As a further solution for fastening, supporting and centring complete torque motors on solid shafts, Ringspann recommends the RTM 608 type clamping systems. They are also configured to customer specifications and allow the motor to be centred "on the fly". Here, a flange ring takes over the connection of the motor to the machine shaft; torque transmission is ensured either with a two-part shrink disc or with a tapered flange ring. The RTM 608 thus enables the connection of a torque motor without any pressure being applied to the rotor of the torque motor.

In addition to the flange ring and the shrink disc, the RTM 608 from Ringspann has a sliding bush. It serves as a second support point. In combination with a centring device, this ensures the required concentricity. For very short shaft ends, a cone clamping element is mounted as a second support instead.

Easy to release - even after a long time

As a further alternative for the frictionally engaged, supported and centred assembly of complete torque motors, Ringspann offers the RTM 134 type clamping systems. Depending on the height of the torque, one or two cone clamping elements are used here between the machine (hollow) shaft and the motor to transmit the torque. A centring ring serves as a second support point. As Marvin Raquet explains, "these cone clamping elements were developed specifically for the special requirements of torque motors. Their taper angle is designed in such a way that they remain easily detachable even after long operation and do not leave any expansion or plasticisation in the mostly thin-walled rotor shafts of the torque motors."