JP3336526B2 - Mold clamping hydraulic circuit for vertical injection molding machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for mold clamping such as a vertical injection molding machine and a press machine, and more particularly to control of a descending speed of a mold clamping cylinder.

[0002]

BACKGROUND ART clamping hydraulic circuit, such as the type of vertical-type injection molding machine or a press machine as shown in FIG. 2, the mold clamping cylinder 1
A piston 5 having a movable plate 4 having a movable mold 3 attached to the tip of a piston rod 2 is slidably fitted in the cylinder, and a cylinder closing oil chamber 6 and a mold opening oil chamber 7 are provided in the cylinder. Is divided into The mold closing oil chamber 6 is provided with a pipe 11 from a hydraulic source 8 via an electromagnetic switching valve 9 and a pilot check valve 10. The mold opening oil chamber 7 is provided with a pipe 16 communicating with the oil tank 15 via the electromagnetic switching valve 9, and a force always acts on the mold opening oil chamber 7 in the mold closing direction based on the weight. Therefore, the piping 16 is blocked by a counterbalance valve 14 whose pressure is controlled by a pilot circuit 13 having a throttle valve 12.

Reference numeral 17 denotes an electromagnetic switching valve for controlling the pilot check valve 10, and reference numeral 18 denotes a check valve.

The operation of the electromagnetic switching valve 9 is described below.
When the electromagnetic switching valve 17 is de-energized as shown in the figure while the solenoid is energized to the position, the hydraulic oil from the hydraulic source 8 is closed from the pipe 11 via the pilot check valve 10 in the open state. Acting on the oil chamber 6, the pressurized oil in the mold opening oil chamber 7 starts the mold clamping at a descending speed by the counterbalance valve 14 controlled by the throttle valve 12.

[0005]

Therefore, the lowering speed of the movable platen 4, that is, the movable mold 3, is controlled by a constant pressure by the throttle valve 12 in the pilot circuit 13 of the counterbalance valve 14, so that the speed of each speed can be varied. Since only control could be performed, for example, high-speed movement, low-speed mold closing, or various changes in speed depending on the resin material and the mold could not be performed.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawback that the descending speed cannot be variously changed as in the prior art, and to remove the disadvantage that the descending speed can be variously changed. An object of the present invention is to provide a tightening hydraulic circuit.

[0007]

According to the present invention, a pipe having a counterbalance valve controlled by a pilot circuit having a throttle valve and a pipe having a pilot check valve are provided in a mold clamping cylinder. 2. Setting of the counter balance valve in a mold clamping hydraulic circuit such as a vertical injection molding machine or a press machine in which two pipes communicate with a hydraulic source and an oil tank via an electromagnetic switching valve.
A hydraulic circuit for mold clamping, such as a vertical injection molding machine, is provided with an electromagnetic relief valve for controlling the pressure in multiple stages.

According to this circuit, it is possible to variously control the Ri <br/> counterbalance valve by the electromagnetic relief valve, it is possible to variously change the descending speed of the mold clamping cylinder.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In the description, the same members as those of the conventional example will be denoted by the same reference numerals, and the description thereof will be omitted. Only the members newly added according to the present invention will be denoted by the new numbers and will be described. According to the present invention, the pilot circuit 13 acting on the counterbalance valve 14 is provided with an electromagnetic relief valve 20 capable of changing the set pressure in various ways. Therefore, the descending speed of the mold clamping cylinder can be variously changed, and it is possible to perform high-speed movement, low-speed mold closing, or multiple speed changes during the mold clamping stroke.

[0010]

As described above, the descent speed can be changed in various ways, and the drawbacks of the conventional circuit initially set forth have been eliminated.

[Brief description of the drawings]

FIG. 1 is a diagram of a mold clamping hydraulic circuit of a vertical injection molding machine or the like showing an embodiment of the present invention.

FIG. 2 is a diagram of a hydraulic circuit for mold clamping of a conventional vertical injection molding machine or the like.

[Explanation of symbols]

 Reference Signs List 1 mold clamping cylinder 2 piston rod 3 movable mold 4 movable plate 5 piston 6 mold closing oil chamber 7 mold opening oil chamber 8 hydraulic power source 9 electromagnetic switching valve 10 pilot check valve 11 piping 12 throttle valve 13 pilot circuit 14 counterbalance Valve 15 Oil tank 16 Piping 17 Solenoid switching valve 20 Solenoid relief valve

Claims (1)

(57) [Claims] A piping having a counterbalance valve controlled by a pilot circuit having a throttle valve and a piping having a pilot check valve are provided in a mold clamping cylinder.
In a mold clamping hydraulic circuit such as a vertical injection molding machine or a press machine in which a pipe communicates with a hydraulic source and an oil tank via an electromagnetic switching valve ,
A hydraulic circuit for mold clamping, such as a vertical injection molding machine, comprising an electromagnetic relief valve for controlling a set pressure in multiple stages.