DC motor linear actuators – soaring forces on a tiny scale.
Advancements in brushless dc motor technology are transforming linear actuation.
Shown here is an example of an 8mm diameter brushless DC motor fitted with an 8mm diameter planetary gearhead. The gearhead output flange contains not only the standard set of preloaded radial ball bearings, but also an additional set of bearings mounted between the radial bearings configured as an axial thrust block. By mounting the gearbox thrust bearings between the radial set, it provides additional separation and increased radial capability. The importance of this bearing system is intrinsically related to the shaft. Close scrutiny of the shaft on this tiny gearmotor reveals its true function – linear movement. The ceramic thread is manufactured with tight tolerances on runout and pitch and with extremely smooth surfaces.
On this example a thread of only 3mm diameter provides up to 27N. This, combined with the precise position control capabilities of DC servo motors, is what enables this device in a world of miniaturisation and automation. All combinations of motor gearhead and actuator are meticulously customised to suit the application and avoid any unnecessary size or weight compromises.
Contact maxon motor Australia for engineering and design assistance on +61 2 9476 4777.