JPS60199560A - Molding machine mold clamping device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention is a molding machine such as a die casting machine or an injection molding machine for plastics, in which a movable platen is moved by a hydraulic device to maintain a fixed mold and a movable mold at a predetermined pressure. This invention relates to a mold clamping device for crimping.

[Prior art]

Molding machines such as die casting machines and plastic injection molding machines perform molding by injecting molten metal or molten resin into the cavity of a fixed mold and a movable mold whose cavity surfaces are pressed together and solidifying it. These are constructed as shown in a schematic side view in FIG.

That is, a fixed platen 2 is fixed on the machine base 1 in the vicinity of an injection device (not shown), and a cylinder platen 3 is fixed on the other end of the machine base 1 in the distance direction with respect to the fixed platen 2. It is formed and fixed so that it can be moved and adjusted freely. Both platens 2,304 corners are nuts 4,5
The platens 2 and 3 are connected by a threaded tie bar 6, and by rotating the nut 4 back and forth on the tie bar 6, the distance between the two platens 2 and 3 can be adjusted. A movable platen T is connected to a tie bar 6 between both platens 2.3.
The fixed platen 2 and the movable platen 7 are supported by the fixed platen 2 and movable platen 7.
In this case, a fixed mold 8 and a movable mold 9 are respectively fixed with their cavity surfaces facing each other.

A hydraulic cylinder 10 is attached to the cylinder platen 3, and a piston rod 11 of the hydraulic cylinder 10 is attached to the center of a link-shaped toggle mechanism 12 that connects the cylinder platen 3 and the movable platen 7. Fixed.

During molding, when the piston rod 11 of the hydraulic cylinder 10 is moved forward, the movable platen 7 is moved via the toggle mechanism 12, and a pressure force is applied between the two molds 8.9 to perform mold clamping. . After clamping, the molding cycle is completed by pouring molten metal into the cavities of the molds 8 and 9 and solidifying it, then retracting the piston rod 11 of the hydraulic cylinder 10, opening the mold, and taking out the molded product. .

In the mold clamping operation of such a molding operation, by providing the toggle mechanism 12, a large mold clamping force can be obtained with a small capacity hydraulic cylinder 10, but due to its characteristics, the toggle mechanism 12 Since the full pressing force is exerted only when the link expands to a predetermined position, the cylinder platen 3 is rotated by rotating the nut 4 according to the thickness t of the molds 8 and 9.
It is necessary to precisely adjust the distance between the platen and the fixed platen 2 by moving the platen.

However, even if the mold size is the same, the thickness t will change if the heating temperature is different, and the tie bar 6 will expand due to the reaction force of the mold line during mold clamping, and the amount of elongation will change depending on the overall length. A predetermined mold clamping force cannot be obtained by simply moving the cylinder platen 3 by a thickness change of 8°9. Therefore, in the past, the tie bar 6 was calculated in advance.
The mold clamping force is adjusted by taking the amount of elongation into consideration with the change in the thickness of the molds 8 and 9 and rotating the nut 4 by an angle corresponding to this, but there is a difference between the calculated amount and the actual amount of adjustment. The disadvantage is that it is often not possible to obtain a predetermined mold clamping force, and it takes a long time to reset the mold clamping force.

[Summary of the invention]

The present invention has been made in view of the above points, and involves fitting an annular member on the cylinder platen side into an annular groove provided at the tie bar butt part of a nut that engages in a recessed part of the cylinder platen. By forming an oil chamber between the bottom surface of the annular member and the end surface of the annular member into which the pressure oil regulated by the relief valve is introduced, the error in mold clamping force due to the elongation of the tie bars during mold clamping can be reduced. The present invention provides a mold clamping device for a molding machine that makes it possible to set a highly accurate mold clamping force in a short time by absorbing it with hydraulic pressure in an oil chamber. Embodiments of the present invention will be described in detail below with reference to the drawings.

〔Example〕

FIG. 2 is a sectional view of the vicinity of a tie bar nut and its hydraulic circuit diagram, showing an embodiment of the mold clamping device of a molding machine according to the present invention. Since the structure of the entire molding machine is the same as the conventional one shown in FIG. 1, a detailed explanation thereof will be omitted, and the explanation will be given later using the same figure when necessary. Although the one shown in FIG. 1 shows an example in which four nuts 4 are rotated individually, in this embodiment, a chain is stretched around a sprocket that is integrated with each of the four nuts, and the four nuts 4 are rotated by a motor. An example is shown in which the two parts are rotated at the same time. In the figure, a cylinder platen 3 to which a hydraulic cylinder 10 is fixed and a movable platen 7 are connected by a link-like toggle mechanism 12, and both platens 3 and 7 are supported on a base 1 so as to be able to move forward and backward. . Further, four tie bars 6 fixed to the fixed platen 2 with nuts 5 are passed through holes in the movable platen T, and further penetrated through holes 3& in the cylinder platen 3 to be projected outward. The tie bar 6 fitting part of the cylinder platen 3 is provided with a stepped recessed part 3b, and the large diameter part thereof has an annular member 21 formed in a stepped annular shape and a washer 22. These members 21 and washers 22 are integrally fixed to the cylinder platen 3 by a presser plate 24 fixed to the end face of the cylinder platen 3 with bolts 23. 25 is a nut screwed onto the threaded portion of the tie bar 6, into which a sprocket 26 is fitted and integrated with a knock pin 27, and a chain (not shown) is installed between the tin rockets 26 of each nut 25. The four nuts 25 are configured to rotate at the same time by rotating a driving tin rocket with a chain stretched thereon by a motor. The threaded portion of the nut 25 with the tie bar 6 is engaged in the recessed portion 3b of the cylinder platen 3, and this engaged portion is slidably fitted into the inner hole of the annular member 21. . In addition, a current groove 25a is provided in this insertion part, and a part of the annular member 21 is fitted into this current condition @25a, and between the bottom surface of the annular groove 25& and the insertion end surface of the annular member 21. An annular oil chamber 28, which is a space, is formed. 29 is a stopper provided on the outer periphery of the nut 25.

30 is a hydraulic device that introduces pressure oil from the oil hole 25b of the oil chamber 28 and the nut 25, and is equipped with a four-way valve 33 connected to a hydraulic pump 31 and a hydraulic tank 32. and the oil hole 25b are connected by a flexible hose 34.

Note that, since the hydraulic device 30 is stationary and the nut 25 rotates, a valve plate made of rotary pulp or the like is provided at the joint between the flexible hose 34 and the oil hole 25b. An accumulator 35 is connected to the four-way valve 33.
A check valve 36 is provided between the direction valve 33 and the hydraulic pump 31. 37 and 38 are relief valves that respectively adjust the oil pressure in the accumulator 35 and the oil pressure in the oil chamber 28.

The mold clamping operation of the molding machine configured as above will be explained.

During molding, a fixed mold 8 is mounted on the fixed platen 2, and a movable mold 9 is mounted on the movable platen 7. Then, the nut 25 is rotated according to the thickness of the molds 8, 9 to perform a conventional so-called die-hide adjustment. Next, the link of the toggle mechanism 12 is folded, the four-way valve 33 is energized, and the pressure oil in the accumulator 35 is introduced into the oil chamber 28 through the flexible hose 34 and the oil hole 25b. As a result, the annular member 21 moves and the cylinder platen 3 also moves in the mold clamping direction.

In this case, the capacity of the accumulator 35 and the position of the stopper 29 are designed so that the amount of movement of the cylinder platen 3 is the maximum amount of extension of the tie bar 6 in this molding machine. Therefore, after demagnetizing the four-way valve 33, the piston rod 11 of the hydraulic cylinder 10 is moved forward, and the toggle machine +
? The mold is clamped by extending the link 912. In this case, the mold clamping force is defined as the projected area of F1 oil pressure 28, A1 oil chamber 2B
If the internal pressure is P, when there are four tie bars 6, F
The formula =4A-P holds true. Therefore, by setting the pressure of the relief valve 38, which determines the pressure P in the oil chamber 28, to a predetermined pressure, the desired mold clamping force can be obtained.

That is, if the set pressure of the IJ leaf valve 38 is low, a lot of the oil in the oil chamber 28 will escape from the IJ leaf valve 38, so the initial movement amount will be reduced.
Eventually, when the desired mold clamping force is reached, oil no longer escapes from the relief valve 38. In this way, the mold clamping force is always determined by the set pressure of the relief valve 38, and remains constant regardless of temperature changes in the molds 8 and 9 and the thickness t of the molds 8 and 9.

After mold clamping, molten metal or resin is supplied into the cavities of the molds 8 and 9 to perform casting or molding, and then the piston rod 11 of the hydraulic cylinder 10 is moved back to open the molds. The four-way valve 33 may be energized for the next inspection at any time, such as before, during, or after opening the mold.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, in the mold clamping device of a molding machine, the annular member on the cylinder platen side is inserted into the annular groove provided in the tie bar threaded portion of the nut that engages in the concave portion of the cylinder platen. By fitting them together and forming an oil chamber between the bottom surface of the annular groove and the end surface of the annular member into which pressure oil regulated by the relief valve is introduced, temperature changes in the mold and Even if there is a change in the elongation of the tie bar due to a change in thickness, this is absorbed by the hydraulic pressure in the oil chamber, and the mold clamping force is determined by the set pressure of the relief valve and always maintains a constant value, resulting in extremely good molding. At the same time, mold clamping force setting time is shortened and productivity is improved.

[Brief explanation of the drawing]

FIG. 1 is a schematic side view of a molding machine shown for explaining the structure and clamping operation of the molding machine, and FIG. 2 is a cross-sectional view of the vicinity of the tie bar nut showing an embodiment of the mold clamping device of the molding machine according to the present invention. Figure 1 and its hydraulic circuit diagram. 2...Fixed platen, 3...Cylinder platen, 3b...O, concave portion, 6...Tie bar, T/fist/movable platen, 8...Fixed mold, 9... ...Movable mold, 12 fists...Toggle mechanism, 21...Reward member, 25...Nut, 25&...Annular groove, 25b
...Oil hole, 28 Φ book/oil chamber, 33, Q...4-way valve, 34e @, e flexible hose, 35-...accumulator, 38...relief valve. Patent applicant Ube Industries Co., Ltd. agent Masaki Yamakawa (T3 or 2 people) :;' I II+

Claims (1)

[Claims] A movable platen and a cylinder platen connected by a toggle mechanism and slidably mounted on a tie bar, and a nut screwed onto the tie bar to restrict movement of the platens due to a reaction force of the mold clamping force, In a molding machine that adjusts the mold clamping force by rotating this nut,
An annular groove into which an annular member on the cylinder platen side is slidably fitted is provided in the tie bar threading part of the nut that engages in the concave part of the cylinder platen, and the bottom surface of the annular groove and the paulownia wood part are connected to each other. A mold clamping device for a molding machine, characterized in that an oil chamber is formed between an end face and into which pressure oil whose pressure is regulated by a relief valve is introduced.