JP2000351141A - Mold clamping apparatus for vertical injection molding machine, etc. - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mold clamping apparatus for a vertical injection molding machine, etc., wherein the number of parts is less, piping work is simple, cost is cheap, a space for fitting a boost cylinder is unnecessary, and a single-acting mold clamping cylinder is provided. SOLUTION: A vertical single-acting mold clamping cylinder 20, a mold clamping ram 22 on one end of which a movable base for fitting a movable mold is fitted and which has an oil through-hole 35 communicated with an inner oil room from the outer peripheral face and is freely slidably inserted in the inner diameter face of the mold clamping cylinder, an overhead tank 24 with a purpose of prefill into the mold clamping cylinder 20 during mold clamping and fitted to the mold clamping cylinder 20, a prefill valve 28 for controlling opening/closing of an oil path between the mold clamping cylinder 20 and the overhead tank 24 and a boost cylinder 30 wherein an oil through-hole 29 which passes through in the axial direction is provided and one end is fixed on the opposite side of the mold fitting side of the mold clamping cylinder 20 and a piston head 31 at the apex part of another end is freely slidably inserted in the oil room of the mold clamping ram 22, are provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device such as a vertical injection molding machine having a single-acting mold clamping cylinder having an overhead tank.

[0002]

2. Description of the Related Art Conventionally, a mold clamping apparatus for a vertical injection molding machine or a die casting machine (hereinafter referred to as an injection molding machine) having a single-acting mold clamping cylinder of this kind is well known.
The clamping device of the vertical injection molding machine as shown in FIG. 1 will be described. A single-acting mold clamping cylinder 3 can move forward and backward with respect to a fixed mold 2 attached to a fixed platen 1 indicated by a chain line (vertical direction in the figure). The movable mold 6 fixed to the movable platen 5 attached to one end of the mold clamping ram 4 fitted to the end of the mold 2 is advanced and retracted.
The oil chamber 9 and the boost cylinder 10 are respectively opened and closed from a pressure source (not shown) via a pipe 7 and a pipe 8.
The mold is closed and clamped by applying pressure oil to the forward-side oil chamber 11.

[0003] An overhead tank 12 is mounted on the upper part of the mold clamping cylinder 3, and when the mold clamping ram 4 advances (moves in the downward direction in the figure) at the time of mold clamping, a prefill valve is provided by pressure oil from a pipe 13. 14 is an overhead tank 12
Open the oil passage 16 between the oil chamber 9 and
5 is introduced into the oil chamber 9 of the mold clamping cylinder 3, and when the mold is opened, the prefill valve 14 keeps the oil passage 16 open, and retreats with the retraction of the boost cylinder 10 (moves upward in the drawing). The working oil 15 in the mold cylinder oil chamber 9 is returned to the overhead tank 12 by the mold clamping ram 4.

Since the mold clamping cylinder 3 is a single-acting type in which the mold clamping ram 4 only advances when the mold is clamped, the mold clamping ram 4 is opened when the mold is opened.
The boost cylinder 10 is attached for the purpose of retracting the boost cylinder.

Unlike the double-acting type, such a single-acting type clamping cylinder 3 has no packing provided on the piston and has a low resistance when the clamping ram 4 rises (retreats) when the mold is opened, so that the ascending operation is smooth. Although performed, a boost cylinder 9 is required for retracting the mold clamping ram.

[0006]

However, as shown in the figure, the boost cylinder is an external component of the single-acting type clamping cylinder, and is operated synchronously with the left and right sides.
It was necessary to mount them individually, which not only increased the number of parts, but also complicated the piping and increased the cost.
Further, there is a disadvantage that a space for mounting the boost cylinder must be secured.

An object of the present invention is to remove the above-mentioned drawbacks, to reduce the number of parts, to simplify the piping work and to reduce the cost, and to further eliminate the need for space for mounting a boost cylinder. It is an object of the present invention to provide a mold clamping device such as a vertical injection molding machine having a cylinder.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention relates to a vertical clamping device such as a vertical injection molding machine having a single-acting clamping cylinder having an overhead tank mounted on a clamping cylinder. A single-acting mold clamping cylinder and a movable plate for attaching a movable mold at one end, and an oil conduction hole communicating from the outer peripheral surface to the internal oil chamber, slidably fitted to the inner surface of the clamping cylinder. The clamp ram attached, an overhead tank attached to the top of the mold clamping cylinder for prefilling the mold cylinder during mold clamping, and a prefill valve that controls the opening and closing of the oil passage between the mold cylinder and the overhead tank And an oil passage hole penetrating in the axial direction, one end of which is fixed to the opposite side of the mold clamping cylinder from the die, protrudes into the mold clamping cylinder, and the piston head at the tip of the other end is a clamping ram. of And a mold clamping apparatus, such as a vertical-type injection molding machine having a single-acting clamping cylinders comprising and a boost cylinder that fits slidably into the room.

According to this device, the boost cylinder is located inside the mold clamping ram, so that there is no need to worry about space, the movable plate can be retracted evenly on the left and right sides, the number of parts is small, and piping work is reduced. Simple and cost-effective.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The single-acting mold clamping cylinder 20 has an inner diameter oil chamber 2
A mold clamping ram 22 is slidably fitted to 1 and an overhead tank 24 containing hydraulic oil 23 is mounted on the upper part for the purpose of prefilling at the time of mold clamping. A prefill valve 28 is provided in an oil passage 27 between the oil chamber 21 and the overhead tank 24, and a prefill valve control pipe 2 is provided.
The oil passage 27 is controlled to open and close by the pressure oil from 5 and 26.

One end of a boost cylinder 30 having an oil passage hole 29 penetrating in the axial direction is fixed to an end of the single-acting mold clamping cylinder 20 opposite to the mold mounting side, and a piston head 31 at the other end is fixed to the clamping cylinder. After passing through the oil chamber 21 of the mold 20, the mold clamping ram 2
2 is slidably fitted to an oil chamber inside the oil chamber 2 and is divided into an oil chamber 32 for advance and an oil chamber 33 for retreat.

An oil passage hole 35 for guiding pressure oil from a hydraulic source (not shown) through a pipe 34 from the outer peripheral surface to the retraction oil chamber 33 inside the mold clamping ram 22 communicates with the forward oil chamber 32. Through the through hole 29 of the boost cylinder 30
From the pressure oil.

An example of a hydraulic circuit for performing the operation described above will be described with reference to FIG. 2. The prefill valve control pipes 25 and 26 are provided with an electromagnetic switching valve 37. The oil passage 27 communicates with the hydraulic pump 38 and the oil tank 39 via the oil tank 39, and controls opening and closing of the oil passage 27 between the overhead tank 24 and the mold clamping cylinder 20.

The pilot pressure of the prefill valve control oil passages 25 and 26 acts on the oil chamber 21 of the mold clamping cylinder 20 via a pilot circuit 40, and a switching valve 44, which is switched by an electromagnetic switching valve 41, is checked. Oil tank 39 and hydraulic pump 3 via valve 42 and electromagnetic switching valve 43
A pipe 45 communicating with 8 is provided.

The boost cylinder 30 has an electromagnetic switching valve 43
Prefill valve control pipe 25 provided in pipe 36
Of the boost cylinder 3 via a pilot check valve 47 in which the pilot pressure of
The pilot pressure of the circuit for communicating with the forward oil chamber 32 of the mold clamping ram 22 through the through hole 29 of the mold clamping ram 22 and the pilot pressure of the same prefill valve control pipe 25 provided on the pipe 34 by the electromagnetic switching valve 43 via the pilot circuit 46. The oil communication hole 35 of the boost cylinder 30 via the pilot check valve 48
And a circuit communicating with the retreating oil chamber 33 of the mold clamping ram 22 through the control unit for controlling the movement of the mold clamping ram 22.

The operation is described below. When the mold is closed, the electromagnetic switching valve 37 is excited to the position a, the electromagnetic switching valve 43 is set to the position b, and the electromagnetic switching valve is set to the position b. When the pump 41 is energized, the hydraulic pump 38
From the electromagnetic switching valve 37a to the pre-fill valve 28 via the pipe 25, and the pre-fill valve 2
8 opens the oil passage 27, the pilot pressure from the pipe 25 acts on the switching valve 44 via the electromagnetic switching valve 41 via the pilot circuit 40, and connects the left chamber of the switching valve 44 to the pipe 45. , Boost cylinder control piping 34
And 36 act on the pilot check valves 48 and 47 to open the pipeline, so that the hydraulic oil from the hydraulic pump 38 is conducted from the oil passage 45 via the electromagnetic switching valve 43 to the oil chamber 21 of the mold clamping cylinder 20. At the same time, the hydraulic oil in the retraction oil chamber 33 is guided from the pipe 36 to the forward oil chamber 32 via the oil communication hole 29, and the hydraulic oil in the retraction oil chamber 33 passes through the pilot check valve 48 and the electromagnetic switching valve 43 opened from the communication hole 35. Since the return to the oil tank 39, the mold clamping ram 22 moves forward (moves downward in the drawing).

As the mold clamping ram 22 moves forward, the oil pressure in the oil chamber 21 becomes negative as the mold clamping ram 22 moves forward.
7 flows into the oil chamber 21 with a large capacity at a time.

When the mold clamping ram 22 reaches the forward limit and the mold closing is completed, the electromagnetic switching valve 37 switches to the position b, the prefill valve 28 closes, the electromagnetic switching valve 41 becomes non-excited, and The pilot pressure from 26 is
The pressure oil from the hydraulic pump 38 acts in the oil chamber 21 to perform mold clamping.

When the mold is opened, the electromagnetic switching valve 37 switches to the neutral position, and when the pilot pressure of the pilot circuit 40 no longer acts on the switching valve 44, the switching valve 44 switches to the right chamber, and the pressure oil in the oil chamber 21 is changed. Flows into the oil tank 39 via the electromagnetic switching valve 41, and when the pressure is released, the electromagnetic switching valve 37 is excited to the position a, the prefill valve 28 opens the oil passage 27, and both pilot check valves 47 and 48 Opens,
Since the electromagnetic switching valve 43 is at the position a, the pressure oil from the hydraulic pump 38 is guided from the electromagnetic switching valve 43 to the pipe 34, then to the oil conduction hole 35 and the retraction oil chamber 33, and the hydraulic oil in the forward oil chamber 32 is moved. Flows from the pipe 36 to the oil tank 39 via the pilot check valve 47 and the electromagnetic switching valve 43, so that the mold clamping ram 2
2 moves upward in the figure, and the hydraulic oil in the oil chamber 21 is returned to the overhead tank 24 from the oil path 27 in the open state.

[0020]

As described above, the number of parts is small,
Piping work is simple and inexpensive, and a mold clamping device such as a vertical injection molding machine having a single-acting mold clamping cylinder that does not require space for mounting a boost cylinder is provided.

[Brief description of the drawings]

FIG. 1 is a view of a mold clamping device such as a vertical injection molding machine having a single-acting mold clamping cylinder according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an example of a hydraulic circuit for controlling a mold clamping device of a vertical injection molding machine having a single-acting mold clamping cylinder according to an embodiment of the present invention.

FIG. 3 is a view of a mold clamping device of a conventional vertical injection molding machine having a single-acting mold clamping cylinder.

[Explanation of symbols]

 Reference Signs List 20 mold clamping cylinder 21 mold clamping oil chamber 22 mold clamping ram 23 hydraulic oil 24 overhead tank 25, 26 prefill valve control pipe 27 oil passage 28 prefill valve 29 through hole 30 boost cylinder 31 piston head 32 forward oil chamber 33 Retraction oil chamber 34 Piping

Claims (1)

[Claims] 1. A mold clamping device such as a vertical injection molding machine having a single-acting mold clamping cylinder having an overhead tank mounted on a mold clamping cylinder, comprising: a vertical single-acting mold clamping cylinder;
A mold clamping ram slidably fitted to an inner surface of a mold clamping cylinder, having a movable plate for attaching a movable mold at one end and having an oil conducting hole communicating from an outer peripheral surface to an internal oil chamber; An overhead tank attached to the top of the mold clamping cylinder for prefilling the mold clamping cylinder during clamping, a prefill valve for controlling the opening and closing of the oil passage between the mold clamping cylinder and the overhead tank, and an oil passage penetrating in the axial direction It has a hole and one end is fixed to the opposite side of the mold clamping cylinder from the mold and protrudes into the mold clamping cylinder, and the piston head at the other end is slidably fitted into the oil chamber of the mold clamping ram. A mold clamping device such as a vertical injection molding machine having a single-acting mold clamping cylinder having a mounted boost cylinder.