This mold-clamping device, which is for an injection molding machine in which resin in injected into a cavity of an open mold, after which the mold is closed to carry out molding, is provided with a movable platen capable of moving along an axial direction of tie bars, and a parallelism maintenance mechanism for maintaining parallelism between a fixed mold and a movable mold when the resin is injected. The parallelism maintenance mechanism includes a contraction member which has a spring member and is for generating biasing force causing the fixed mold and the movable mold to separate from each other, and a length adjustment member for adjusting the biasing force generated by the contraction member.

Provided is a mold clamping device that can simplify the component count or structure by including a mold thickness adjustment mechanism that reduces the load on a power source, is easily maintained, and has high design flexibility. Also provided is a mold clamping device that can set a long distance (daylight) between molds without having to upsize the entire mold clamping device and can simplify the component count or structure. A mold clamping device for split molds includes a first platen, a second platen, a pressure receiving platen, and a mold thickness adjustment mechanism disposed on the pressure receiving platen. At least one of the first platen and the second platen is able to move back and forth so as to approach or depart from the other. The pressure receiving platen is located on a side remote from the first platen, of the second platen. The mold thickness adjustment mechanism includes a rod-shaped rotation member, a power source configured to rotate the rotation member around a rotation axis of the rotation member, the rotation axis being parallel to a longitudinal direction of the rotation member, and a pair of converters configured to convert rotation direction of the rotation member into a movement direction of the second platen. A mold clamping device for split molds includes polygonal first and second platens, a pressure receiving platen, and a toggle mechanism. At least one of the first platen and the second platen is able to move back and forth so as to approach or depart from the other. The pressure receiving platen is located on a side remote from the first platen, of the second platen. The toggle mechanism is disposed between the second platen and the pressure receiving platen and on a diagonal line of the second platen and configured to cause the first and second platens to approach or depart from each other.

When an injection molding machine performs molding, the mold clamping force on the mold is adjusted on the basis of a mold displacement of the mold or the injection peak pressure and injection foremost position so that the molding is performed without causing flash and by an appropriate mold clamping force with which energy can be reduced. The amount of mold displacement and also the injection peak pressure and the injection foremost position are monitored during automatic operation. If there occurs no mold displacement change exceeding a threshold or if there occurs no injection peak pressure anomaly or injection foremost position anomaly exceeding thresholds, the automatic operation is continued. If the mold displacement change occurs or if the injection peak pressure anomaly and the injection foremost position anomaly occur, the operation of the injection molding machine is stopped.

A mold clamping mechanism includes a seal member for sealing in lubricant that has leaked from a through-hole, attached to a peripheral side surface of a tie bar exposed from the moving platen, and a housing that is separate from the moving platen, contacts a surface of the moving platen, and covers the tie bar, from the moving platen to the seal member, and the seal member.

A mold clamping device (20) includes a traction platen (29) disposed below a pressure-receiving platen (22), a movable platen (28) disposed above the pressure-receiving platen (22) and configured to be moved up and down by a mold opening and closing mechanism (27), and tie bars (31) extending downward from the movable platen (28) and penetrating the pressure-receiving platen (22) and the traction platen (29). The mold clamping device (20) is configured to clamp molds (12) disposed between the pressure-receiving platen (22) and the movable platen (28). A saw tooth portion (36) is formed at a lower end of each of the tie bars (31), and a half nut (26) that engages with the saw tooth portion (36) is provided under the traction platen (29).

A movable platen according to the present invention includes: a mold clamping platen 42 having a projecting portion 62 in a mold closing direction-side surface; a mold mounting platen 44 mounted to the projecting portion 62 of the mold clamping platen 42; and a guide mechanism 50 fixed to the mold clamping platen 42 and supporting the mold mounting platen 44. Only the mold clamping platen 42 is fixed to the guide mechanism 50, while the mold mounting platen 44 is not fixed but placed on platen surface support portions 52.

A safety apparatus includes a safety bar that is capable of moving in a mold clamping direction and a mold opening direction, in conjunction with a moving platen provided with a movable mold, and a latch that contacts the safety bar when a door, which is provided in a cover of an injection molding device, is open, wherein the latch includes a notch in a surface thereof on the mold-opening-direction side.

A drive mechanism for an injection molding machine that causes a movable object to undergo movement includes a driving motor that generates a driving force, a drive pulley connected to the driving motor, a driven pulley connected to the movable object, and a plurality of belts (a wide belt and a narrow belt) of equal length, the belts being arranged in parallel with each other and trained around the drive pulley and the driven pulley.

A mold clamping apparatus according to the present invention includes: a fixed platen to which one mold of a pair of molds is to be mounted; a movable platen which is disposed opposite the fixed platen and to which the other mold is to be mounted; a pressure-receiving platen connected to the fixed platen via tie bars; a mold opening/closing mechanism including a toggle link mechanism for opening/closing and clamping the molds by moving the movable platen back and forth; a drive mechanism including a servo motor for driving the mold opening/closing mechanism; and a control device for controlling the servo motor, wherein the control device includes an acceleration/deceleration adjustment section capable of adjusting an acceleration time, a deceleration time and a target speed of the servo motor during a mold clamping operation.

An injection molding machine is equipped with a screw having a spline shaft formed with a spline on an outer circumferential surface, a bush having a spline hole formed with a spline on an inner circumferential surface, a linear motion motor for moving the bush in an axial direction of the screw, a rotational motion motor for rotating the bush about an axis of the screw, and a motor control unit which, in the case of fitting the spline shaft in the spline hole, controls the linear motion motor to advance the bush in a direction approaching the screw in a state that the bush and the screw are separated, and which controls the rotational motion motor to rotate the bush when the acquired output torque becomes equal to or larger than a first predetermined torque.