Adjusting drive for a steering column and steering column for a motor vehicle

A motor-adjustable steering column for a motor vehicle comprising:

• an adjusting drive comprising:
• a motorized drive unit;
• an external threaded spindle which has an external thread and a coaxial internal thread;
• and
• an internal threaded spindle disposed within the external threaded spindle and engaged with the coaxial internal thread;
• wherein the external threaded spindle and the internal threaded spindle are configured to be driven in rotation relative to one another about an axis by the drive unit;
• wherein the external threaded spindle engages with its external thread in a drive nut, wherein the drive nut or the internal threaded spindle is configured to be driven in rotation by the drive unit and is supported relative to the drive unit in the direction of the axis;
• and
• wherein the motorized drive is arranged between casing tubes of a casing unit which are axially adjustable relative to one another telescopically and which bear a steering spindle and/or which is arranged between a support unit which is able to be connected to the motor vehicle and a casing unit rotatably receiving a steering spindle.