JPS59152832A - Injection molder - Google Patents

Abstract

PURPOSE:To obtain an injection molder that would not cause defective molding or damage to a mold due to deflection of a support post, by extending a support beam that supports an injection unit in a direction away from the position of the support post, and providing a balance cylinder to the extended end of the support beam. CONSTITUTION:The support beam 6 attached to the upper end of the support post 5 is extended in a direction away from the position of an end 6a where a clamping cylinder 7 is attached and the balance cylinder 15 is attached to the extended end 6b. The lower end of a piston rod 16 of the balance cylinder 15 is secured to a frame 1. The relation between the attaching position x2 of the balance cylinder 15 and the attaching position x1 of the clamping cylinder 7 must be such that the moments of the cylinders are equal.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to an injection molding machine in which an upper mold is directly attached to an injection unit that is connected to a mold clamping cylinder and can be raised and lowered, and in particular, an upper mold is mounted on the opposite side of a column that supports the injection unit. This invention relates to an injection molding machine equipped with a balance cylinder.

In recent years, injection molding machines suitable for the intermittent production of a wide variety of small molded products in small quantities have been developed. A type has been proposed in which the attached upper mold is brought into contact with the lower mold together with the injection unit, the mold is closed and clamped, and the injection operation is performed as is.

FIG. 1 shows an injection molding machine of the above type. Type 4
is installed. On the other hand, on the frame 1 is a support column 5.
is erected, and a support rod 6 is provided in the shape of a cantilever at the upper end. The tip end 6a of the support beam 6
A mold clamping cylinder 7 is attached to the mold clamping cylinder 7, and an injection unit 9 is connected to the piston rod 8 of the mold clamping cylinder 7.The injection unit 9 is guided by the support 5 by a guide arm 10 and can move up and down. There is. Injection unit 9
An upper mold 12 is directly attached to the heating cylinder 11 at the tip, and faces the lower mold 4 at the injection position.

In the above configuration, during injection molding, the injection unit 9 is lowered by the mold clamping cylinder 1, the upper mold 12 at the tip is closed and clamped with respect to the lower mold 4, and then the injection work is performed. After the injection work is completed, a predetermined holding pressure is maintained.
After a cooling period, the injection unit 9 is raised by the mold clamping cylinder 7, the upper mold 12 is separated from the lower mold 4, and the mold is opened.

According to the above-mentioned prior art, the upper mold plate is omitted and the upper mold is directly attached to the tip of the injection unit.
There is no need to provide a nozzle at the tip of the heating cylinder (and the resin passage is correspondingly short), which reduces the chance of the resin deteriorating and hardening due to overheating, and allows for consistently uniform molded products during intermittent production. Moreover, the elimination of the upper template had the advantage of simplifying the structure.

However, in the above-mentioned prior art, since the injection unit 9 is supported by the support beam 6 at the upper end of the support column 5, the reaction force of the mold clamping pressure during mold clamping acts on the tip 6a of the support beam 6. Since the reaction force acts on the upper end of the column 5 via the support beam 6 as a moment in the clockwise direction in the figure, the upper end of the column 5 will be deflected in the clockwise direction.

If the above-mentioned support is bent, uniform contact cannot be obtained between the mold mating surfaces of the upper and lower molds 12.4 (and a gap is created between them, making it impossible to secure sufficient mold clamping pressure, resulting in defects). It had the disadvantage of producing molded products.In addition,
Since the contact between the molds is not uniform, there is also the disadvantage that the mold mating surfaces are scratched and the molds are damaged.

The object of the present invention is based on the above-mentioned prior art (in view of problems such as deflection of the support due to structural constraints of an injection molding machine, a support beam that supports an injection unit is extended to the opposite side with respect to the support, and the extended end By providing a balance cylinder in the support section, the above-mentioned drawbacks and disadvantages are eliminated, and an excellent injection molding machine that is free from molding defects and mold damage caused by deflection of the support can be provided. That is.

In accordance with the above object, the structure of the present invention is to counter the moment acting on the upper end of the column due to the reaction force against the mold clamping pressure during mold clamping during injection work, and automatically equalize the moment with the balance cylinder. The gist of this method is to apply moments in opposite directions to the column that are equal to each other, thereby canceling out the moments acting on the column and preventing the column from becoming deflected.

Next, an embodiment of the present invention will be described below based on FIGS. 2 and 3.

A support beam 6 attached to the upper end of the support column 5 is extended in a direction opposite to the end 6a of the support beam 6, and a balance cylinder 15 is attached to the extended end 6b. As is clear from FIG. 3, the lower end of the balance cylinder 15 and the histone rod 16 are fixed to the frame 1. The head side chamber 15a of the balance cylinder 15 is communicated with the head side chamber 7a of the mold clamping cylinder 7 through a common pipe L]. Similarly, both rod side chambers 15b and 7b are communicated through a common pipe L2. The mounting distance of the mold clamping cylinder 7 from the pillar 5 to the position is XI,
The relationship between the distance KA x 2 to the cylinder 15 is determined by both cylinders γ and the cross-sectional area of the cylinder 15.

Note that the other components are the same as those indicated by the same reference numerals in FIG.

In the above configuration, when clamping the mold during injection work,
High-pressure hydraulic oil is supplied to the head side chamber 7a of the mold clamping cylinder T, and the upper mold 12 and the lower mold 4 are clamped.
The reaction force acts on the column 5 as a clockwise moment.
acts on the upper end of At this time, at the same time, hydraulic oil of the same pressure is supplied to the head side chamber 15a of the balance cylinder 15 through piping. However, the cylinder 15
Since the piston rod 16 is fixed to the frame 1 and cannot be moved, the reaction force that supports the hydraulic pressure acts on the support beam 6 via the cylinder 15, and the reaction force causes a counterclockwise moment. This will act on the upper end of the column as follows. These two moments in opposite directions cancel each other out, and in the end, no bending moment acts on the support column 5.

In this case, the mounting position of the balance cylinder 15 'Rx
2, the mounting of the mold clamping cylinder 7 is set in relation to the position Xi so that the above two moments are equal. For example, when the cylinder diameters of both cylinders 15 and T are the same, are attached at equal distances (xl=x2), but the invention is not necessarily limited to this.

As described above, according to the present invention, the injection unit is connected to the mold clamping cylinder attached to the support beam provided on the support column and supported so as to be able to rise and fall freely, and the upper mold is directly attached to the injection unit, and the mold clamping cylinder is attached to the support beam provided on the pillar. In an injection molding machine in which upper and lower molds are clamped by lowering an injection unit by a cylinder, the support beam is extended in a direction opposite to the end of the clamping cylinder with respect to the support beam, and a balance cylinder is attached to the extended end. By doing this, when the mold is clamped, the moment that acts on the column based on the reaction force that moves all at once on the support beam via the mold clamping cylinder, is simultaneously applied to the column based on the reaction force that acts on the opposite end of the support beam by the balance cylinder. This is canceled out by the moment acting in the opposite direction, so in the end, no bending moment is generated on the column, and the column has the excellent effect of not bending in the slightest even under intense mold clamping pressure. .

Therefore, molding defects and damage to the mold due to the deflection of the support can be completely avoided.

Since the head side chamber and rod side chamber of both cylinders are piped in common, the mold clamping pressure and balance pressure automatically become the same pressure, and in order to apply the same moment, the cylinder diameter and mounting of both cylinders must be adjusted. Since it is sufficient to consider the position, it has the advantage that the moment to the column can be balanced very easily.

In addition, since the balance cylinder is simply added to the conventional device, there is a practical benefit in that the conventional device can be used as is and only minor modifications are required.

[Brief explanation of drawings]

FIG. 1 is a side view showing a conventional technique, and FIG. 2 and subsequent figures show embodiments of the present invention. FIG. 2 is a side view, and FIG. 3 is a sectional view of a main part. 1... Frame 4... Lower mold 5.
...Strut 6...Support beam 7...
... Mold clamping cylinder 9 ... Injection unit 12 ... Upper mold 15
...Balance cylinder 16 ...Piston rod Patent applicant Yamaguchi Seiki Seisakusho Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] A lower mold 4 disposed on a frame 1, a support beam 6 provided on a post 5 erected on the frame, a mold clamping cylinder 7 attached to an end of the support beam, and a mold clamping cylinder 7 attached to an end of the support beam. In an injection molding machine consisting of an injection unit 9 that is connected to a cylinder and can be raised and lowered, and an upper mold 12 that is directly attached to the injection unit, the support beam 6 is extended in the opposite direction with respect to the support column, and the extension end is The balance cylinder 15 is attached to the cylinder 6b, the lower end of the piston rod 16 is fixed to the frame, and the head side chambers 7a, 15a and the rod side chambers 7b, 15b of the two cylinders 7.15 are connected in common, respectively. injection molding machine.