Injection mechanism of an injection molding machine
AssigneeFanuc Corporation
InventorsSusumu Ito, Koichi Nishimura
Life of this patent
Estimating the term…
Abstract
The tip of a ball screw (28) is mounted so as to be rotatable with respect to a pusher plate (14) but immovable in the axial direction. A ball nut (31), which mates with the ball screw (28), is attached to a rear plate (2) through a load cell (33). Even though a force in the rotating direction is applied to the ball nut (31) through friction as the ball screw (28) rotates, the applied force never acts as a force to rotate the pusher plate (14). Thus, the level of sliding resistances between the pusher plate (14) and guide rods has nothing to do with the magnitude of the rotatory force of the ball screw, so that resin pressure components can accurately be extracted from the output of the load cell (33).
Claims15
An injection mechanism of an injecting molding machine, which comprises:
- an assembly including a front plate, a rear plate, and a pusher plate, wherein the front plate is connected to the rear plate, the pusher plate is guided in the direction of an injection axis to be movable between the front and rear plates, and the pusher plate supports a rear end portion of an injection screw so as to be rotatable with respect to the pusher plate and the pusher plate engages with the tip of a screw;
- a load cell fixed to part of a member, which forms said assembly;
- a nut fixed to said load cell and mating with the screw;
- a first drive source and first rotation transmitting means for rotating said injection screw;
- and
- a second drive source and second rotation transmitting means for rotating said screw to move the screw in the axial direction with respect to the ball nut;
- wherein:
- engagement of said screw with the pusher plate is based on an arrangement such that the screw engages said pusher plate so as to be rotatable with respect to said pusher plate, and
- the load cell is fixed to the rear plate, which forms the assembly, so that the nut is fixed to the rear plate through the load cell.
An injection mechanism of an injection molding machine comprising:
- an assembly including a plurality of parallel guide rods, a front plate and a rear plate fixed individually to the opposite ends of each of these guide rods, and a pusher plate movable between said front and rear plates by being guided with said guide rods, the pusher plate supporting the rear end portion of an injection screw so as to be rotatable with respect to the pusher plate and engaging with the tip of a ball screw;
- a force sensor fixed to said rear plate;
- a ball nut fixed to said force sensor and mating with the ball screw;
- a first drive source and first rotation transmitting means for rotating said injection screw;
- and
- a second drive source and second rotation transmitting means for rotating said ball screw to move the ball screw in the axial direction with respect to the ball nut;
- an injection mechanism of an injection molding machine, and wherein:
- engagement of said ball screw with the pusher plate is based on an arrangement such that the ball screw engages said pusher plate so as to be rotatable with respect to said pusher plate and immovable in an axial direction, wherein said pusher plate includes a main pusher plate and an auxiliary pusher plate mounted integrally on a side of said main pusher plate, said main and auxiliary pusher plates being always kept so as to face each other across the rear plate and a predetermined space;
- a rear end portion of said injection screw is supported on the main pusher plate so as to be rotatable with respect to said main pusher plate such that a screw sleeve attached to the rear end portion of the injection screw is inserted in a through hole formed in the center of the pusher plate, the inserted screw sleeve being supported on the main pusher plate so as to be rotatable with respect to said main pusher plate;
- engagement of said ball screw with said main pusher plate is based on an arrangement such that a tip of the ball screw is inserted in an internal space of said screw sleeve, which is inserted in a center through hole of the main pusher plate, the inserted ball screw being supported in the screw sleeve so as to be rotatable with respect to said screw sleeve and immovable in the axial direction;
- and
- the rear end of said ball screw is rotatably supported by support means attached to said auxiliary pusher plate.
Dependencies are inferred from the claim text.