JPH0255214B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field to which the Invention Pertains] The present invention relates to the structure of a drive section of an electric motor-driven injection molding machine, and particularly relates to a rotary drive shaft and an electric motor used for mold opening/closing operations or injection operations of an injection molding machine. This relates to a structure in which the rotor is integrated.

[Prior art and its drawbacks]

The mold opening/closing operation or injection operation in conventional motor-driven injection molding machines converts the rotary motion of the electric motor into linear motion or approximate linear motion using ball screws and link mechanisms, and power transmission mechanisms such as gear trains, chains, and sprockets. is driven by. The same goes for the screw rotation drive, in which power is transmitted from the rotation of the electric motor to the screw drive shaft via a transmission mechanism such as a gear train or a chain sprocket.

Therefore, not only the mechanical structure becomes large, but also
This has the disadvantage that the rotational inertia of the drive system increases, which reduces the responsiveness of not only starting and stopping the operation but also controlling acceleration and deceleration. [Object of the Invention] It is an object of the present invention to provide an electric motor-driven injection molding machine which eliminates the above-mentioned drawbacks, makes the apparatus compact, reduces rotational inertia, and improves control responsiveness.

[Key points of the invention]

In order to achieve the above-mentioned purpose, the rotational motion of the electric motor is converted into linear motion or approximate linear motion by a screw transmission mechanism or link mechanism, or directly transmitted to the drive system as rotational motion. In this injection molding machine, a rotor of an electric motor is integrally connected to a rotary drive shaft of a drive system for at least one operation of each operation such as , screw rotation, etc.

〔Example〕

Next, one embodiment of the present invention will be described with reference to FIG. 1. Reference numeral 11 is a screw fitted into the heating cylinder 12 so as to be rotatable and movable forward and backward. Said screw 11
is integrally attached to the drive shaft 13 with a key 14 and a split collar 15. The stator coil 1 16 is integrally connected to the rotor 17 by a ball screw, so that the stator coil 1 is integrally disposed on the injection bracket 18.
It is rotated by the rotational force generated in response to the change in the magnetic field due to the control of energization to 9. A nut 20 is engaged with the ball screw 16, and moves forward and backward on the ball screw 16 as the ball screw 16 rotates. 21 is a thrust box with the nut 20 and thrust bearing 22 inside.
is housed therein, and is adapted to receive a thrust load from the screw 11 and a thrust load from the forward movement of the nut 20 (moving to the left in the figure).

Therefore, when the ball screw 16 rotates, the same screw 1
When the nut 20 moves forward, the screw 11 moves forward, and when the nut 20 moves backward (moves to the right in the figure), the thrust box 21 moves forward and backward on the ball screw 16. Screw 1 integrally attached to the drive shaft 13
It is designed to pull back 1. Reference numeral 23 denotes a guide shaft that prevents rotation of the thrust box 21 and guides movement of the thrust box 21 due to the rotation of the nut 20 and the screw described later. A rotor 24 is integrally attached to the drive shaft 13, and generates rotational force in response to changes in the magnetic field by controlling the energization of a fixed coil 25 integrally attached to the thrust box 21, thereby rotating the screw 11. It is something. 26 is a fixed die plate, 27
are movable die plates, each of which has a fixed mold 28 and a movable mold 29 attached thereto, and both molds 28 and 29.
When they are joined at the mold joint surface A, a mold cavity is formed. 30 is a screw shaft attached to the movable die plate 27, and when the nut 31 meshed with the screw shaft 30 rotates, the screw shaft 30,
That is, the movable die plate 27 moves back and forth, and the mold 2
8 and 29 are opened and closed.

A rotor 32 is integrally attached to the nut 31 and is rotated by controlling the supply of electricity to a stator coil 34 integrally attached to an end plate 33. 35 is a brake shoe for locking the outer periphery of the screw shaft 30; 36 is a wedge for pressing the brake shoe 35 against the outer periphery of the screw shaft 30; 37 is the wedge 36 for locking the brake shoe 35;
This is an electric or hydraulic cylinder unit for pressing or releasing.

[Action action]

The structure is as described above, and its operation will be explained next. When the stator coil 34 attached to the end plate 33 is energized, the nut 31 to which the rotor 32 is attached rotates.
The screw shaft 30, that is, the movable die plate 27 moves forward (rightward in the figure), and the molds 28 and 29 are joined at the mold joint surface A. At this time, the energization to the stator coil 34 is controlled so that both the molds 28 and 29 are clamped with a predetermined pressing force, and when the molds 28 and 29 are joined, the cylinder unit 37
pushes the wedge 36, and the brake shoe 35 locks the screw shaft 30. Therefore, stator coil 3
Even if the power supply to 4 is stopped, the necessary mold clamping force is maintained and does not loosen.

On the other hand, on the injection side, the stator coil 25 integrally attached to the thrust box 21 is energized to rotate the drive shaft 13 to which the rotor 24 is attached, that is, the screw 11, melting the material supplied from the hopper. The inside of the heating cylinder 12 is transferred and the screw 11
Accumulate measurements in front of the. During this time, the screw 11 is at the retracting limit position, and when the mold clamping described above is completed, it moves forward in order to inject the measured material.
(Moves to the left in the figure.) This forward movement rotates the ball screw 16 by controlling the energization of the stator coil 19 attached to the injection bracket 18, and the nut 20 that meshes with the screw 16, that is, the screw 11 connected to it, rotates. It is designed to be pushed forward (leftward in the figure).
Injection is carried out as described above, and when the material in the cavity has finished cooling and solidifying, the cylinder unit 37 pulls out the wedge 36 and the brake shoe 35 unlocks the screw shaft 30. Next, stator coil 34
Then, electricity is applied in the opposite direction to that during the mold clamping described above, the screw shaft 30 is moved back, and the mold is opened.

[Effects] As explained above, the mold opening/closing, injection operation, screw rotation operation, etc. are driven by an electric motor, and the rotary drive shaft of the operation drive system is the rotor of the electric motor, so the device is compact and rotational. The inertia is small, and the responsiveness of acceleration and deceleration control as well as starting and stopping of operation is good, eliminating the drawbacks listed at the beginning.

[Brief explanation of drawings]

FIG. 1 is a diagram showing one embodiment of the present invention. 11... Screw, 13... Drive shaft, 16... Ball screw, 17, 25, 32... Rotor, 18... Injection bracket, 19, 25, 34... Stator coil, 2
0,31...Natsuto, 21...Thrustbox, 2
2... Thrust bearing, 26... Fixed die plate, 27... Moving die plate, 30... Screw shaft, 3
3... End plate, 35... Brake shoe.

Claims (1)

[Scope of Claims] 1. A first stator coil that is rotatably and freely movable back and forth and is integrally disposed on an injection bracket that firmly holds a heating cylinder into which a screw is inserted;
a first rotor facing the stator coil and integrally connected to a first ball screw rotatably disposed within the injection bracket; a second stator coil that is integrally attached to a thrust box that integrally fixes and houses a first nut that meshes with the first ball screw; An electric motor-driven injection molding machine characterized by having a plasticizing drive electric motor constituted by a second rotor that is rotatably housed in the screw and is integrally attached to a screw drive shaft connected to the screw. 2. A first stator coil which is integrally disposed on an injection bracket which firmly holds a heating cylinder into which a screw is fitted, so as to be rotatable and movable back and forth;
a first rotor facing the stator coil and integrally connected to a first ball screw rotatably disposed within the injection bracket; a second stator coil that is integrally attached to a thrust box that integrally fixes and houses a first nut that meshes with the first ball screw; a plasticizing drive electric motor constituted by a second rotor which is rotatably housed in the screw and is integrally attached to the screw drive shaft connected to the screw; and a second rotor which is integrally attached to the movable die plate. a third stator coil integrally attached to the end plate; a third stator coil integrally attached to the end plate; a third stator coil integrally attached to the end plate; 1. A motor-driven injection molding machine characterized by having a mold clamping drive motor configured by a third rotor facing the stator coil and integrally attached to the second nut.