Nissei Plastic Industrial Co., Ltd.

Kinji Yokoya

Hiroshi Yamaura

Atsushi Koide

Hiroo Okubo

Keizou Shimizu

A screw shaft for driving an injection screw driving body in a motor-driven injection device is coupled to a motor shaft of an electric motor in engagement of splines. A spline for the motor shaft engaging with a spline disposed at the outer periphery at a shaft end of the screw shaft is fitted into a recess formed inside of a motor shaft end. A flange formed around the spline is clamped at end face of the motor shaft via a bolt, and is formed at the inner periphery of a bearing sleeve detachably mounted to the motor shaft. An annular groove is formed at the inner periphery of an opening of the bearing sleeve for the side of the screw shaft. A ring member for air-tightly sealing a clearance formed between the screw shaft and the bearing sleeve is fitted into the annular groove. The spline for the motor shaft engaging with the spline on the screw shaft is disposed at the inner periphery of the bearing sleeve independent of the motor shaft, thus achieving the coupling via the respective splines of the motors.

Coupling structure between injection driving screw shaft and electric motor in injection device

Centering of an injection heating cylinder and screw driver is provided even after assembly, using an electric injection mechanism with height adjustment for the screw driver. A front plate is provided with an injection heating cylinder having a screw installed inside at the front middle and a rear plate is provided with are electric motor for injection-driving. The plates are affixed to an installation member. The front and rear plates are linked by guide bars installed between them. The screw driver is inserted into the guide bar and movably disposed between the plates. A driving mechanism connected to an electric motor is composed of a ball screw shaft and a ball nut member, and is installed over the screw driver and the rear plate. A centering member slidably supports the screw driver and, moreover, provides height adjustment, and is installed at the sides of the screw driver.

Electric injection mechanism

The present invention reduces an excessive gnawing force at the thread engagement region of a ball screw portion with the ball nut member that tends to be generated in the electric injection mechanism and prevents an abnormal wear or break of the ball screw shaft by installing a stress relaxation means of annular groove at the shaft portion of the ball screw shaft. A ball nut member is engaged by threads with a pair of right and left ball screw shafts rotatably provided in parallel with guide bars over front and rear plates. The shaft portion between the front plate of the ball screw shaft and the ball screw portion is partially formed with a diameter smaller that the root diameter of the ball screw shaft, and a stress relaxation groove with a concave curved surface having a flat bottom is disposed in the shaft portion.

A pressure detection apparatus of an injection molding machine composed of a drive mechanism and a movable member includes a pressure reception member disposed in the drive mechanism in such a manner as to be movable in a reciprocating direction of the movable member while being guided by a guide member. A ball screw or nut of a ball screw mechanism of the drive mechanism is fixedly attached to the pressure reception member. A load cell is disposed between the drive mechanism and the movable member in such a way as to be fixedly attached to one of a bearing ring retainer facing the movable member and the pressure reception member while abutting the other. The pressure reception member receives stress (load) directed in a rotation direction and arising from the ball screw or nut, thereby preventing imposition of the stress (load) on the load cell.

Growing community of inventors

Nagano-ken, Japan

Kinji Yokoya