JPH11198192A - Injection mold - Google Patents

Abstract

(57) [Problem] To provide an injection molding die in which a hydraulically driven slide core structure can be incorporated without increasing the size of the die. A cylinder chamber including a cylinder and a bush is provided inside a slide core. There is a piston 5b and a cylinder rod 5c in the cylinder chamber. One end of the cylinder rod 5c is connected and fixed to a fixing plate 6 adjacent to the slide core 2. A hydraulic pump 10 capable of generating hydraulic pressure, a flow path switching valve 9 capable of switching the direction of generation of hydraulic pressure in the cylinder chamber, and a controller 8 capable of interlocking the operation of the molding machine and the driving of the slide core 2 Hydraulic pressure generating device 11 The cylinder chamber is partitioned by the piston 5b, and the slide core 2 is driven by injecting or discharging pressure oil 7 from the hydraulic pressure generating device 11 to the front and rear of the piston 5b in the cylinder chamber.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection mold having a hydraulically driven slide core mechanism.

[0002]

2. Description of the Related Art Conventionally, a slide core is generally used for injection molding a molded article having an undercut. As a method of driving the slide core, a method of operating with an angular pin is often used. However, when moving a slide core with a long stroke, such as when molding a pipe joint,
The drive stroke for removing the core must be long. When a large number of slide cores need to be moved in order, a mechanism such as an angular pin is complicated and unsuitable.

One of the methods for driving such a slide core is to operate a hydraulic cylinder with a solenoid valve,
There is a method in which the mold opening, the core pulling out, and the ejecting operation are interlocked with the limit switch electrically (“Injection molding die design example 102 selection”, P250-P253, Industrial Research Institute).

The structure of a mold used in this method is, for example, as shown in FIG. 4, a slide core block 20 is provided between a movable mold plate 4 and a fixed mold plate 1 of an injection mold. The slide core block 20 has a core 3 at the tip, and a piston rod 5c connected to the rear end of the slide core block 20 passes through a fixed plate 60 with an O-ring attached to the movable mold plate 4. It is connected to the piston 5b in the cylinder block 50.

[0005] A hydraulic pressure generating device 11 is provided outside the mold, whereby the piston 5 b in the cylinder block 50 can be moved forward and backward by the pressurized oil 7. FIG. 4 is a view showing the mold open state of the mold, and the piston 5b
Is at the most retracted position of the cylinder block 50, that is, at the retreat limit. FIG. 5 is a diagram showing a position in which the piston 5b has moved forward by the pressurized oil and is most advanced, that is, a state in which the piston 5b is at the forward limit. In the slide core block 20 in which the piston 5b is positioned at the forward limit, the core 3 forms a cavity together with the fixed mold plate 1 and the movable mold plate 4 by closing the mold.

[0006]

However, in this mold, since the cylinder block 50 is installed outside the movable mold plate 4, the amount of protrusion from the mold is large, and the outer size is increased, so that the mold is mounted on a molding machine. Sometimes it is difficult to pass between the tie bars of the molding machine.
A special molding machine capable of removing the tie bar was required. Therefore, manufacturing equipment tends to be expensive in order to use this method. An object of the present invention is to provide an injection molding die in which a hydraulically driven slide core structure can be incorporated into an injection molding die without increasing the size of the die in view of the above points.

[0007]

According to the present invention, there is provided a fixed mold plate, a movable mold plate and a slide core, wherein the slide core is provided between the fixed mold plate and the movable mold plate, and the mold is closed. Forming a cavity portion in the cylinder chamber inside the slide core, having a piston rod and a piston, the piston rod is connected and fixed to the mold body,
Injection molding characterized in that the cylinder chamber is partitioned by the piston, and the piston can be moved forward and backward by injecting pressurized oil from outside the mold to one of the front and rear sides of the piston and discharging it from the other side to the outside of the mold. It is a mold.
The pressure oil used in the present invention is oil having a pressure for driving a piston in a cylinder chamber.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an open state of an injection mold according to an embodiment of the present invention. A slide core 2 is provided between the fixed mold plate 1 and the movable mold plate 4, and a core 3 which forms a cavity in a mold closed state is provided at an end of the slide core 2. A cylinder 5 is provided inside the slide core 2. The cylinder chamber is formed by closing the cylinder 5 with a bush 5e, and includes a piston 5b and a piston rod 5c in the cylinder chamber. The cylinder chamber is partitioned by a piston 5b, and an O-ring 5 attached to the piston 5b is provided.
a prevents oil leakage between the front and rear of the piston 5b.

[0009] The tip of a piston rod 5c is connected to the piston 5b.
e. Piston rod 5c and bush 5e
There is a hydraulic seal 5d between them so that even if the bush 5e slides, no oil leaks from the bush 5e. The piston rod 5c passes through the bush 5e and is connected to a fixed plate 6 attached to an end of the movable mold plate 4.

Outside the mold, there is a hydraulic pump 10 and a hydraulic pressure generator 11 comprising a flow path switching valve 9 capable of switching the direction of pressure oil injection. The hydraulic pump 10 can generate pressurized oil by supplying and discharging oil at a constant pressure. The flow path switching valve 9 connects the oil path in the forward direction, disconnects the oil path,
It is possible to switch between three types of connection in the reverse method. Between the cylinder 5 and the hydraulic pump 10, a forward oil pipe 12 and a backward oil pipe 13
Connected by In addition, the forward oil pipe 1 of the slide core 2
2. It is preferable to provide a flow control valve on both the retreat oil pipe 13. Thus, the movement speed of the slide core 2 can be adjusted by adjusting the flow rate of the oil. Controller 8
Is connected to the flow path switching valve 9 and a control signal generator (not shown) of the molding machine, and interlocks the oil passage of the flow path switching valve 9 with a desired operation signal such as opening / closing of the mold of the molding machine, and protruding of a product. Can be switched.

Next, the operation of the slide core 2 of the injection mold according to the embodiment of the present invention will be described. Upon receiving a mold opening completion signal output from a control signal generator (not shown) when the mold opening process is completed from the molding machine, the controller 8 determines that the mold opening is completed, and connects the flow path switching valve 9 in the reverse direction. Pressure oil 7 from hydraulic pump 10 to retreat oil pipe 1
3, the hydraulic oil is discharged from the cylinder 5 to the hydraulic pump via the forward oil pipe 12, and the slide core 2 is retracted. FIG. 1 shows a state after the slide core 2 has retreated.

Further, when the product ejection process of the molding machine is completed, the controller 8 which has received the ejection completion signal output from the control signal generator (not shown) judges that the ejection is completed, and switches the flow path switching valve 9. The connection is made in the forward direction, and the pressure oil 7 is injected from the hydraulic pump 10 into the cylinder 5 through the forward oil pipe 12, and at the same time, the pressure oil 7 is discharged from the cylinder 5 to the hydraulic pump through the retreat oil pipe 13 to advance the slide core 2. . FIG. 2 shows a state after the slide core 2 has moved forward. When the forward movement of the slide core 2 is completed, a forward completion signal of the slide core 2 is output from the controller 8, and the mold closing process of the molding machine is started. FIG. 3 is a diagram when the mold closing is completed.

By performing such an operation, the slide core 2 can be retracted to a position where it comes off from the undercut portion of the molded product. It can also be advanced to the position where the cavity is formed. The flow path switching valve 9
The slide core 2 can be stopped at a predetermined position when the injection of the pressure oil 7 is stopped by setting the connection state to the non-connection state.

[0014]

According to the present invention, the size of the injection mold having the slide core structure can be reduced. Therefore, a small-sized molding machine can be used and manufacturing equipment can be made appropriate.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a mold open state according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a slide core in an advanced state according to the embodiment of the present invention;

FIG. 3 is a sectional view showing a mold closed state in the embodiment of the present invention.

FIG. 4 is a sectional view of a conventional hydraulically driven slide core structure of an injection molding die in an open state.

FIG. 5 is a cross-sectional view showing a conventional hydraulically driven slide core structure of an injection molding die in a slide core advanced state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fixed-side template 2 Slide core 3 Core 4 Movable-side template 5 Cylinder 5a, 5d O-ring 5b Piston 5c Piston rod 5e Bush 6 Fixing plate 7 Pressure oil 8 Controller 9 Flow control valve 10 Pump 11 Oil pressure generating device 12 Forward Oil pipe 13 Retreat oil pipe 20 Slide core block 50 Cylinder block 60 Fixed plate with O-ring

Claims (1)

[Claims] 1. A fixed mold plate, a movable mold plate and a slide core, wherein the slide core is provided between the fixed mold plate and the movable mold plate to form a cavity in a mold closed state. A piston rod and a piston are provided in a cylinder chamber inside the slide core, and the piston rod is connected to and fixed to a mold body; the cylinder chamber is partitioned by the piston; Wherein the piston can be moved forward and backward by injecting pressurized oil into the mold and discharging the oil from the other side to the outside of the mold.