US 7,404,709 B2Granted

Injection unit of injection molding machine

AssigneeFanuc Corporation

InventorsKoichi Nishimura, Koji Shima, Yasuo Naito

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Abstract

The invention provides an injection molding machine injection unit that eliminates adverse effects on the load cell of belt tension due to belt drive. A load cell that detects resin pressure is mounted on a pusher plate and a rotation-transmitting member, on which an injection screw is fixedly mounted, is axially supported by an inner annular part of the load cell. The shaft of a pulley is axially supported on the pusher plate and coupled by splines to the rotation-transmitting member. A screw rotation motor is mounted on motor mounts of a housing mounted on the rear surface of the pusher plate. Tension on a belt run between the pulley and a pulley mounted on the motor output shaft concentrates a force at the base of the motor mounts. However, the housing is separate from the pusher plate and fixedly mounted on the pusher plate at a location other than that occupied by the base of the motor mounts. Therefore, the belt tension does not adversely affect the load cell, thus enabling high-accuracy resin pressure detection.

Claims2

Dependent claims

An injection unit for rotating and axially moving an injection screw of an injection molding machine, comprising:

a first member arranged linearly movable and having a front face closer to the injection screw and a rear face remote from the injection screw;
a pulley shaft rotatably supported by said first member and having a pulley fixed thereon on a rear side of said first member;
a rotation-transmitting member connected with said pulley shaft such that a relative axial displacement therebetween between is allowed, and connected with a rear end of the injection screw, for transmitting rotation of said pulley shaft to the injection screw;
a load detection member mounted on the front face of said first member and having an inner annular portion supporting said rotation-transmitting member rotatably such that a relative axial displacement in between is inhibited, for measuring a resin pressure acting on the injection screw;
a second member not integrally formed with said first member and attached to the rear face of said first member;
a screw-rotation motor mounted on said second member for rotating the pulley fixed on said pulley shaft through a belt;
and
thrust force applying means for applying a thrust force to said second member so that the injection screw is axially moved.

5 more elements

Dependencies are inferred from the claim text.