The miniature GVCM-019-032-02 Linear Voice Coil Servo Motor has been released by Moticont. It is only three-quarters of an inch (19.0 mm) in diameter and features a 0.875 in. (22.2 mm) stroke.  Also called an electric cylinder, this miniature linear servomotor, features a continuous high-force-to-size ratio of 7.4 ounces (2.1 N) and 23.3 ounces (6.5 N) of peak force at a 10 percent duty cycle. Featuring: High reliability, high speed, zero cogging, high acceleration/deceleration, and when used in a servo loop, very high accuracy, and repeatability, these non-commutated, brushless miniature linear servomotors are clean, and quiet.  They are an ideal choice for: Haptic feedback, pipetting, medical devices, laser machining and drilling, workholding and clamping, scanners, laser beam steering and filtering, optical focusing, dynamic vibration absorption, testing, sorting, and assembly.  

The housing is only 1.250 in. (31.8 mm) long and combined with coil end the total length is 1.438 in. (36.6 mm).  In the fully extended position, the threaded shaft extends 1.156 in. (29.4 mm) beyond the face of the housing and the end of the shaft has a 2-56 UNC-2A thread 0.156 in. (4.0 mm) long for backlash free connections. Both the housing and coil ends of the actuator have two 4-40 UNC-2B threaded mounting holes on 0.313 (7.9 mm) bolt circles for easy integration into an application, they should be considered as low-cost replacements for pneumatic linear actuators.