Design of Tubular Linear Motors
A tubular linear motor is a linear motor with a cylindrical form, which stator winding envelopes the bar-shaped armature (solenoid winding). The stator winding can be fed by sinusoidal or trapezoidal current and connected as one-phase or multi-phase system. The armature consists of magnets and iron, which produces the radial magnetical flux perpendicular to the stator winding. The translational movement is generated through the armature reaction to the Lorentz force on the winding. The machines are normally used as a direct drive, e.g. in a pick-and-place application or as a shaker system. A tubular linear motor with axial magnetized magnets (2 poles) is shown in the figures: A 3D-illustration of the armature and the stator winding without end winding (left) and the cross section of the machine (right).