New SRP direct drive from HEIDENHAIN with integrated motor and sensing delivers smooth motion

Now SRP series integrated direct drives from HEIDENHAIN integrate MRP series angle-encoder modules with ETEL torque motors having very low detent torque. These direct drives deliver smooth motion control for exacting positioning and measuring tasks.Precision rotary axes are complex, which is why integrated designs with tested and specified properties (instead of those made by machine builders of numerous separate components) excel.

SRP series direct drives have compact dimensions and large hollow shafts. They include HEIDENHAIN angle encoder modules and ETEL integrated torque motors for precise drive, control, and measurement of motion tasks. Click to enlarge.

This higher performance (from integrated options) is what drove HEIDENHAIN to offer integrated MRP angle-encoder modules — including a bearing with high guideway accuracy and high rigidity as well as low and consistent moment of friction for steady rotary motion. Now taking it a step further is the pairing of this angle-encoder module with a torque motor to make the rigid and compact SRP series.

There’s far less installation and calibration time; a simple mechanical interface eliminates critical mounting tasks and elaborate matching of subcomponents otherwise needed to complete the assembly.

The SRP series drives are particularly well suited to the requirements of metrology applications. Here, high motor torque is generally unimportant — but high resolution and repeatability (even under varying operating temperatures) is paramount. Custom modifications are possible.

HEIDENHAIN-manufactured bearings and the encoders are matched to the ETEL torque motors. More specifically, the specially designed rolling bearings outperform conventional bearings with special adaptation to rotary-axis requirements. Emphasis was placed on a compact and lightweight design; high-speed and load-bearing capacities were deemphasized. HEIDENHAIN verifies the bearing accuracy at the actual guideway to quantify the deviation between the actual rotary axis and target nominal rotary axis. So radial and axial guideway accuracy (and wobble) are all well-defined … and there’s distinction between reproducible and non-reproducible error.

SRP series direct drives include bearings that HEIDENHAIN designs, manufactures, and verifies. Shown here is simplified schematic of bearing-guideway measurands and measured locations that HEIDENHAIN quantifies to supply exact accuracy values.

The encoders are available in absolute and incremental versions with high line count and minimal interpolation error, positioning noise, and drift instability.

The ETEL torque motor is a slotless type that combines high torque density and low detent torque with a symmetrical construction and modal coil. It has none of the slots of motors with classic windings, as its design includes an airgap winding that allows rotor de-energization and a constant magnetic field through te rotor rotation.

Noise has minimal effect on control and measuring accuracy. AccurET controllers from ETEL are compatible with the SRP series direct drives where applications need maximal dynamics and position stability. For more information, visit heidenhain.us/resources-and-news/integrated-drive-motor-smooth-motion-control.