| 摘要 |
<p>An electro-mechanical injection actuator (20) as arranged to controllably rotate and translate a feedscrew relative to a frame (28) to express plastic material into a mold. The improved actuator includes a ball-screw (24) mounted on the frame, the ball-screw having a nut (26) matingly engaging a screw (25), the screw being attached to the feedscrew (F); an electric metering motor (21) mounted on the frame and having a rotatable output shaft (22), the rotational movement of the output shaft being transmitted to the screw through a splined connection (40, 41); an injection motor (45) mounted on the frame and operatively arranged to selectively rotate the nut relative to the frame; and a unidirectional clutch or brake (29) operatively arranged between the nut and frame for permitting the nut to rotate relative to the frame only in the angular direction needed to translate the feedscrew in a direction to express plastic material into the mold. The clutch/brake prevents the nut from being moved in the opposite angular direction under the influence of pressurized plastic material in the mold.</p> |
