JPH0736732Y2 - Clamping device for injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a mold clamping device of an injection molding machine.

(Prior Art) In a conventional mold clamping device for an injection molding machine, a tie bar is fastened to a movable plate with a nut, and a mold clamping cylinder, a split nut, and a mold thickness adjusting device are provided on a fixed platen. The movable platen was supported by linear bearings.

(Problems to be solved by the invention) In the mold clamping device of the conventional injection molding machine, since the tie bar is fastened to the movable plate, the tie bar acts as a load on the linear motion bearing that supports the movable plate (mold Tie bar weight is about 20 tons in a 4000 ton class injection molding machine. Therefore, there is a drawback that wear of the linear motion bearing is increased and life is shortened. Similarly, the power required to open and close the movable plate also increases with the weight of the tie bar, and when fastening the tie bar to the movable plate, the tightening force of the nut must exceed the mold clamping force. In an injection molding machine, seizure or the like occurs in a screw portion, which makes it difficult to tighten the screw. Therefore, it is necessary to use a tightening tool. However, in this case, there is a problem that the structure, dimensions, etc. are restricted due to the restriction of the tightening tool.

The present invention is intended to solve the above conventional problems by providing a tie bar and a mold thickness adjusting device on the stationary platen side.

(Means for Solving the Problem) For this reason, the present invention is an injection molding method in which a male screw or groove provided at the end of a tie bar is meshed with a female screw provided at a split nut to apply a mold clamping force to the tie bar. In a mold clamping device of a machine, a split nut is provided on the movable platen side, and a tie bar and a mold thickness adjusting device are provided on the fixed platen side, which is a means for solving the problem.

(Operation) Move the mold thickness adjustment stopper on the fixed platen side by the amount determined by the known mold thickness, and move the tie bar with the ram of the mold clamping cylinder until the stopper contact plate hits the stopper. . As a result, the split nut on the movable platen side and the groove or ridge of the tie bar are aligned with each other so that they can be engaged. Further, the movable platen and the tie bar are coupled by meshing the split nut and the tie bar, and the tie bar is transmitted by applying a hydraulic mold clamping force to the ram inside the mold clamping cylinder on the fixed platen side. When the mold clamping force is transmitted to the tie bar, the gap between the split nut and the groove or screw of the tie bar and the extension of the tie bar become
The sliding support bearing of the fixed plate for holding the tie bar is slidably moved. The deviation between the tie bar and the split nut due to the application of the mold clamping force is returned to its original state by pushing the ram of the mold clamping cylinder back until the stopper contact plate comes into contact with the mold thickness adjusting stopper, and thereafter the above operation is repeated.

(Embodiment) The present invention will be described below with reference to the embodiments of the drawings. FIGS. 1 to 4 show an embodiment of the present invention. In the figure, the injection molding machine mold clamping mechanism is used for injection molding of plastic or the like by clamping the mold 11 with the movable platen 3 and the fixed platen 10. Further, a male groove or a screw is provided on the end of the tie bar 1 on the movable plate side, and a female groove or a screw is provided on the split nut 2 forming a pair therewith. Then, by engaging them with the split nut opening / closing cylinder 5, the tie bar 1 and the movable platen 3 are connected. In addition, the mold clamping force is applied to the ram 9 in the outer cylinder of the mold clamping cylinder that is integrated with the fixed platen 10 (the tie bar 1 is pushed to the fixed platen 10 side).
As a result, the mold clamping force is transmitted to the tie bar 1 fitted in the ram 9, so that the movable platen 3 and the fixed platen 10 clamp the mold 11. The mold thickness adjusting stopper 8 can be expanded and contracted (for example, the fourth
The cap nut 8A and the bolt 8B are as shown in the figure, and the length (dimension B in FIG. 3) is determined by the thickness of the mold (dimension A in FIG. 2). Tie bar 1 fitted into ram 9
When is pushed by applying a returning force to the ram 9 on the movable platen 3 side, the stopper contact plate 7 attached to the end of the tie bar 1 on the fixed platen 10 side hits the stopper 8 for die thickness adjustment and stops.

Then, at this stopped position, the groove or screw of the tie bar 1 and the groove or thread ridge of the split nut 2 are exactly aligned with each other, and normal meshing is possible. The tie bar 1 moves slightly when the mold clamping force is applied and when it is returned to the movable platen 3 side.
The movable platen 3 is supported by sliding support bearings 12 of 10 and the movable platen 3 is made to travel by expansion and contraction of the mold opening / closing cylinder 6. Movable plate 3 and mold 11
The weight of the movable half of the above is supported by the linear bearing 4. When the movable platen 3 is run, the tie bar 1 and the split nut 2 do not mesh with each other, so the tie bar 1 is supported by the sliding support bearings 12 of the fixed platen 10 and does not act as a load on the linear motion bearing 4.

(Effect of the Invention) As described above, in the present invention, since the tie bar and the mold thickness adjusting device are provided on the fixed plate side, the weight of the tie bar does not become a load on the linear motion bearing that supports the movable plate, and the tie bar does not compare to the conventional machine Wear is reduced and a long life can be achieved. Similarly, the power required to open and close the movable plate added to the mold opening / closing cylinder can be reduced, and the operating cost can be reduced. Further, since it is not necessary to fasten the tie bar to the movable plate, a fastening nut is unnecessary and the assembly cost required for fastening can be reduced. Also, there is no risk of seizure between the tie bar and the fastening nut.

[Brief description of drawings]

FIG. 1 is a side sectional view of a mold clamping device according to an embodiment of the present invention when a mold is opened, FIG. 2 is a side sectional view of the same mold clamping, and FIG. 3 shows a relationship between a tie bar and a split nut during mold clamping. Side view showing, No. 4
The figure is a detailed sectional side view of the stopper for adjusting the mold thickness. Description of main parts of the figure 1 tie bar 2 ...... split nut 3 ...... movable plate 4 …… linear motion bearing 5 …… split nut opening / closing cylinder 6 …… mold opening / closing cylinder 7 …… stopper contact plate 8 …… mold thickness Adjusting stopper 9 …… Mold clamping cylinder inner ram 10 …… Fixed plate 11 …… Mold 12 …… Sliding support bearing 8A …… Mold thickness adjusting stopper cap nut 8B …… Mold thickness adjusting stopper bolt

Claims (1)

[Scope of utility model registration request] 1. A male screw or groove provided at the end of the tie bar,
In a mold clamping device of an injection molding machine that engages a female screw provided on a split nut and applies mold clamping force to a tie bar, a split nut is provided on the movable plate side, and a tie bar and a mold thickness adjusting device are provided on the fixed plate side. A mold clamping device for an injection molding machine, which is provided.