Mold clamping apparatus having ballscrew directly connected to rotor of servo motor

A mold clamping apparatus for clamping a mold consisting of a stationary mold half and a movable mold half, said mold clamping apparatus comprising:

• a stationary plate to which said stationary mold half is to be fixed;
• a movable plate to which said movable mold half is to be fixed and which is disposed so as to be opposed to said stationary plate in a predetermined direction;
• and a moving device which moves said movable plate toward and away from said stationary plate in said predetermined direction, so as to close and open said mold, wherein said moving device comprises:
• a plurality of ballscrew shafts each of which extends in said predetermined direction from said stationary plate toward said movable plate, and each of which is supported at one of axially opposite end portions thereof by said stationary plate, so as to be rotatable relative to said stationary plate and so as not to be displaceable relative to said stationary plate in an axial direction thereof;
• a plurality of servo motors which drive the respective ballscrew shafts, and which are disposed on one of opposite sides of said movable plate remote from said stationary plate, each of said servo motors having a rotor which is connected to the other of said axially opposite end portions of the corresponding one of said ballscrew shafts such that said rotor and the corresponding ballscrew shaft are rotatable together;
• and
• a plurality of ballscrew nuts which engage the respective ballscrew shafts and are fixed to said movable plate, so as to be moved in said axial direction by rotations of said respective ballscrew shafts, for thereby moving said movable plate toward and away from said stationary plate in said axial direction.