JPH079619Y2 - Clamping device for injection molding machine - Google Patents

Description

[Detailed description of the device]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device for an injection molding machine, which has a small-diameter large-stroke mold opening / closing cylinder, a large-diameter small-stroke mold clamping cylinder, and a movable mold clamping cylinder at a mold closing position. The present invention relates to a so-called mechanical lock direct pressure type mold clamping device including a lock mechanism that mechanically engages with a board.

[0002]

2. Description of the Related Art A mechanical locking direct pressure type mold clamping device of an injection molding machine is equipped with a fixed plate, a movable plate and a support plate (also called a mold thickness adjusting plate). Both the mold clamping cylinder and the mold opening / closing cylinder are provided on the support board to enable the operation and to avoid the supply of the hydraulic pressure to the movable member as much as possible.

Examples of this type of mold clamping device are, for example, Japanese Examined Patent Publication No. 2-42022, Japanese Utility Model Publication No. 3-16211,
Japanese Unexamined Patent Application Publication No. 3-35859 discloses that the mold clamping cylinder is arranged at the center of the support plate, the mold opening / closing cylinders are arranged on both sides of the support plate, and the mold clamping cylinder is directed toward the ram of the mold clamping cylinder on the back face of the movable plate. A mold clamping force transmission rod is provided, a cavity for accommodating the mold clamping force transmission rod is provided in the mold clamping ram, and a lock that engages the tip of the mold clamping ram and the tip of the mold clamping force transmission rod in the mold closed state. A mechanism is provided.

In FIG. 5 of Japanese Utility Model Laid-Open No. Hei 3-16211, a mold clamping cylinder is used as a ring-shaped cylinder to form a through hole at the center of the mold clamping piston and a mold clamping force provided on the movable plate at the time of mold opening. The structure in which the transmission rod is inserted into this through hole is shown as a conventional structure.

[0005]

The conventional mechanical locking direct pressure type mold clamping device has the following problems because the movable platen is opened and closed by two mold opening and closing cylinders. The first problem is due to the secular change of the sealing material inserted in the sliding part.
This is a problem that the balance of the force of the die opening / closing cylinder is disturbed and the smooth operation of the movable plate is impaired. Once such an imbalance occurs, an uneven driving force is applied to the movable plate, which accelerates the uneven wear of the tie bar bushes and further promotes the imbalance.

The second problem is that the repeatability of the stop position of the movable plate becomes low, and there is a problem especially when a three-plate type mold is used. In addition, when the mold is closed, the parallelism between the mating surfaces of the fixed mold and the movable mold becomes irregular, and the mold protection pressure for detecting foreign matter adhering to the mating surfaces does not act evenly on the mating surfaces. Occurs.

The third problem is that it is difficult to use the cylinder with a cushion because it is difficult to adjust the throttle amounts of the cushions of the two mold opening / closing cylinders to be the same. Therefore, it is necessary to reduce the amount of oil on the hydraulic circuit side to avoid impact at the stroke end,
The hydraulic circuit becomes complicated.

The present invention has been made to solve the above problems.

[0009]

In the mold clamping device of the present invention, a ring-shaped mold clamping cylinder 10 is arranged in the center of a support plate 3, and a mold extending from the back of the movable plate 2 in the center of the mold clamping piston 11. A through hole 12 for inserting the clamping force transmission rod 8 is provided, and the mold opening / closing cylinder 25 is attached to the mold clamping cylinder 10.
It is arranged on the central axis of the above and has a structure in which the support plate 3 and the mold clamping force transmitting rod 8 are connected by the piston rod 26 penetrating the through hole 12. A mechanical lock device 24 that engages the tip of the mold clamping force transmission rod 8 and the tip of the mold clamping piston 11 when the movable platen 2 moves to the mold closing position is provided.

As the locking device 24, the male spline 9 is used.
And a structure utilizing the engagement of the spline teeth by the rotational movement of the female spline 16, and the piston rod 26 of the mold opening / closing cylinder can pass between the tip of the mold clamping force transmission rod 8 and the tip of the mold clamping piston 11. A structure in which the mold clamping force transmission plate 37 provided with the notch 38 is inserted can be adopted.

[0011]

According to the above structure, since both the mold clamping and the mold opening / closing are performed by the single cylinder 10, 25 arranged at the center of the movable platen 2, not only the mold clamping force but also the mold opening / closing force and the mold protection. All the pressure acts on one center of the movable platen 2. Since there is only one mold opening / closing cylinder 25, no imbalance of force, stop position, or speed acts on the movable platen 2.
Further, as the mold opening / closing cylinder 25, a cylinder having a normal structure including a cushion mechanism can be used.

[0012]

1 to 8 show a first embodiment of the present invention, in which 1 is a fixed platen, 2 is a movable platen, 3 is a support platen, 4
Is a tie bar, 5 is a fixed mold, 6 is a movable mold, and 7 is an ejector built-in portion integrated with the movable platen 2.

A mold clamping force transmission rod 8 having a compressive strength capable of withstanding the mold clamping force is provided behind the center of the movable platen 2, and a short male spline 9 is provided at the tip thereof. A ring-shaped mold clamping cylinder 10 having a large diameter and a small stroke is formed at the center of the support board 3, and a male spline 9 can pass through the axis center of a mold clamping piston 11 fitted therein. A through hole 12 having a diameter is provided.
Reference numeral 13 denotes a cylinder cover of the mold clamping cylinder 10, and a mold clamping side oil chamber 14 and a return side oil chamber 1 are provided before and after the mold clamping piston 11.
5 is formed.

The tip of the mold clamping piston 11, that is, the movable platen 2
A female spline 16 fitted to the male spline 9 of the mold clamping force transmission rod is rotatably attached to the end portion on the side by pressing the plate 17 and the lock cylinder bracket 18 for axial movement. There is.

As shown in FIGS. 1 and 2, the mold clamping piston 11
3 is projected from the cylinder cover 13, and shallow parallel chamfered portions are provided on both sides in the left-right direction of FIG. The cylinder cover 1 is attached to the parallel chamfer.
A guide block 19 fixed to 3 is in sliding contact with the mold clamping piston 11 to prevent it from rotating around its axis. A slide key can also be used as this rotation preventing means.

As shown in FIG. 3, a lock cylinder 21 having a trunnion structure is attached to the lock cylinder bracket 18 fixed to the end surface of the mold clamping piston 11. The lock cylinder 21 has a rod end and a female end. The tip of the arm 22 fixed to the end surface of the spline 16 is connected by a pin 23 in a direction parallel to the spline axis. Therefore, the female spline 16 reciprocally rotates as the rod of the lock cylinder 21 moves back and forth. The rotation angle at this time is an angle corresponding to 1/2 of the pitch of the teeth of the splines 9 and 16. Although FIG. 3 shows a spline having six teeth with a coarse pitch, a spline having a finer pitch is actually used.

At the rear end of the central portion of the support board 3, one die opening / closing cylinder 25 is mounted. The piston rod 26 of the mold opening / closing cylinder is located on the central axis of the support plate 3, and thus of the movable plate 2, and the through hole 12 of the mold clamping piston 11 is formed.
The front end is connected to the front end of the mold clamping force transmission rod 8 through.

4 to 8 are detailed views showing the connecting structure of the piston rod 26 and the mold clamping force transmitting rod 8 of the mold opening / closing cylinder. As shown in FIGS. 4 and 5, the parallel chamfered portion 4 is provided at the tip of the piston rod 26 of the mold opening / closing cylinder.
1 and a screw part 42 are provided, and a locking block 43 formed by removing both opposing peripheral surfaces of the disk to form a rectangular shape having a short arc side is screwed to the screw part 42, and a lock nut 44 is used. The screwing position is fixed.

On the other hand, at the tip of the mold clamping force transmitting rod 8, as shown in FIGS. 6 and 7, a spline plate 30 which is substantially integrated with the mold clamping force transmitting rod 8 by an anchor 46, a knock pin 47 and a bolt 48. The spline plate is provided with an insertion opening 49, which is larger than the above-described locking block 43 by an amount of clearance, and a circular engagement groove 50, which is connected to the insertion opening 49, at the axial center of the spline plate. An escape hole 51 for accommodating the lock nut 44 is provided in the center of the tip of the tightening force transmission rod 8.

At two locations near the peripheral surface of the engaging groove 50, stopper pins 53 in the axial direction are mounted with both ends supported by the spline plate 30 and the tip of the mold clamping force transmitting rod 8, and are substantially mounted. A set screw 55 facing the direction of the stopper pin 53 is screwed and mounted on the spline plate 30 so as to be screwed into the engagement groove 50.

As shown in FIGS. 1 and 2, the mold opening / closing cylinder 25 is fixed by providing a projecting portion 56 at the rear end of the support board 3, and a working opening 57 shown in FIG.
6 are provided on both side surfaces. When the movable platen 2 is moved to the maximum retracted end, the connecting portion between the piston rod 26 and the mold clamping force transmitting rod 8 is located at the portion where the opening 57 is provided, and the parallel chamfered portion of the piston rod is formed. Four
1 and the set screw 55 can be operated from the working opening 57.

The connecting work between the piston rod 26 and the mold clamping force transmitting rod 8 of the mold opening / closing cylinder configured as described above is performed as follows. First, the mold opening / closing cylinder 25 is fixed to the support plate 3, and the movable platen 2 is then moved in a state where the locking block 43 at the tip of the piston rod 26 and the insertion port 49 at the tip of the mold clamping force transmission rod are in phase. After moving to the retracted end, the locking block 43 is inserted into the engagement groove 50 through the insertion port 49. At this time, the locking block 43 and the insertion port 49 are phase-aligned with each other by stopping the movable platen 2 at a position immediately before the insertion so as to bring the two in close proximity to each other, and then applying a spanner to the parallel chamfered portion 41 to cause the piston to move. It can be easily performed by rotating the rod 26.

After inserting the locking block 43 into the circular engagement groove 50, a spanner is applied to the parallel chamfer 41 to rotate the piston rod 26 by about 90 degrees, and the locking block 43 is brought into contact with the stopper pin 53. . Then, the set screw 55 is advanced so that the locking block 43 is fixed by being sandwiched between the stopper pin 53 and the set screw 55. At this time, it is preferable to apply an adhesive or the like that solidifies in the anaerobic atmosphere to the set screw 55 to prevent it from loosening. The piston rod 26 and the mold clamping force transmission rod 8 may be separated in the reverse order of the above.

Piston rod 26 and mold clamping force transmitting rod 8
The connecting structure with the above is not limited to the above structure, but by adopting the above connecting structure, the piston rod 26 and the mold clamping force of the mold opening / closing cylinder 25 in a state where the mold opening / closing cylinder 25 is mounted on the support board 3 in advance. The connection work with the transmission rod 8 can be performed, and the workability at the time of assembling the mold clamping device can be significantly improved.

Next, the operation of the mold clamping device configured as described above will be described. FIG. 1 shows a state when the mold is clamped, and FIG. 2 shows a state when the mold is opened. From the mold opened state of FIG. 2, hydraulic pressure is supplied to the head side of the mold opening / closing cylinder 25 to extend the piston rod 26. , The movable platen 2 is moved forward until the mating surfaces of the fixed mold 5 and the movable mold 6 come into close contact with each other. The position of the movable platen (or movable mold) at the time of mold closing is detected by an encoder (not shown), and if the mold closing position is not reached, it is considered that foreign matter has caught the mating surface of the mold. It is judged that the mold clamping operation is not started to protect the mold.

During the mold closing operation, hydraulic pressure is supplied to the return side oil chamber 15 of the mold clamping cylinder 10 and the mold clamping piston 11 is moved to the side opposite to the movable platen. On the other hand, the female spline 16
The teeth of the male spline 9 are rotated to an angle that passes through the groove of the female spline 16. Accordingly, the male spline 9 is not blocked by the female spline 16 and
When the movable platen 2 reaches the mold closing position after passing through 6,
A slight play is formed between the tip of the mold clamping force transmission rod 8 (correctly, the end surface of the spline plate 30) and the end surface of the female spline 16.

Next, the hydraulic pressure is supplied to the lock cylinder 21 to rotate the female spline 16 so that the teeth of the male spline 9 and the teeth of the female spline 16 are in the same phase.
And the hydraulic pressure is supplied to the mold clamping side oil chamber 14 of the mold clamping cylinder 10. A large mold clamping force generated by the mold clamping cylinder 10 having a large diameter is transmitted to the movable platen 2 via the female spline 16, the male spline 9 and the mold clamping force transmission rod 8.

After the molding work is performed in this mold clamping state, hydraulic pressure is supplied to the return side oil chamber 15 of the mold clamping cylinder 10 to retract the mold clamping piston 11, and the tip of the mold clamping force transmitting rod 8 and the female end. After the pressing force with the end surface of the spline 16 is released, the lock cylinder 21 rotates the female spline 16 in a phase in which the teeth of the male spline 9 and the grooves of the female spline 16 match, and then the rod of the mold opening / closing cylinder 25. The hydraulic pressure is supplied to the side, the movable platen 2 retracts, and the mold open state shown in FIG. 2 is restored.

By applying a force to the center of the movable platen 2 with one mold opening / closing cylinder 25 as described above, the mold opening / closing operation does not occur as in the conventional two-cylinder without imbalance in force and position. Can be controlled smoothly, and the mold protection operation and stop position will be accurate. Furthermore, since a well-known cushion function can be added to the mold opening / closing cylinder 25, the impact at the time of stop can be mitigated without adding a meter-out throttle valve to the hydraulic circuit, and the stop position can be controlled with higher accuracy. Like

In the structure of the above-described embodiment in which the mold opening / closing cylinder 25 is projected to the rear of the support board 3, a screw rod for stroke adjustment is axially screwed into the head end of the mold opening / closing cylinder 25, and It is possible to adopt a structure in which the opening / closing stroke of the die is regulated by mechanically regulating the retracted end of the piston by advancing and retracting the screw rod.

The lock device 24 of the first embodiment uses a spline, but a lock device having a structure as shown in FIGS. 9 to 11 can be adopted as a simpler structure. 9 to 11, the mold clamping force transmitting plate 37 is inserted laterally between the end surface 35 of the mold clamping force transmitting rod 8 advanced to the mold closing position and the tip end surface 36 of the mold clamping piston 11. , Through the mold clamping force transmission plate 37, the mold clamping piston 1
The fastening force of 1 is transmitted to the movable platen 2. In the structure of the present invention, since the piston rod 26 extending from the tip of the mold clamping force transmitting rod 8 to the through hole of the mold clamping piston 11 is present, the mold clamping force transmitting plate 37 includes the piston rod 2
It is necessary to provide a notch 38 for avoiding interference with 6.

As a structure for advancing and retracting the mold clamping force transmitting plate 37 between the mold clamping piston 11 and the mold clamping force transmitting rod 8, as shown in FIG. 10, a mold pivotably attached to the support plate 3 is used. A structure in which the tightening force transmission plate 37 is rocked by a rocking cylinder 39,
As shown in FIG. 11, various structures such as a structure in which the mold clamping force transmission plate 37 is connected to the rod of the direct acting type cylinder 40 and moved forward and backward by linear movement can be adopted.

In the first embodiment, the mold opening / closing cylinder 25 is provided at the rear of the support board 3. However, as shown in FIG.
The tip of a piston rod 26, which is built into the mold clamping force transmitting rod 8 and extends rearward from the tip of the mold clamping force transmitting rod 8, passes through the through hole 12 of the mold clamping piston 11 and is coupled to the flange 58 of the support plate 3 on the side opposite to the lock mechanism. A structure can be adopted.

In this structure, the supply of hydraulic pressure to the mold opening / closing cylinder 25 becomes a little troublesome and the mold clamping force transmission rod 8 also becomes thicker, but since the mold opening / closing cylinder 25 does not project to the rear of the support board 3, the mold clamping is performed. This is effective when you want to make the device compact.

[0035]

According to the structure of the present invention described above,
Not only the mold clamping force but also the mold moving force from the mold opening / closing cylinder and the mold protection pressure always act on the center of the movable platen, so that the movable platen moves smoothly and the stopping accuracy is high. Also, the mold opening / closing cylinder can have a cushioning function to absorb the shock when the movable platen is stopped, so that the movable platen can be smoothly stopped without shock and the hydraulic circuit is simplified. Also, control of the hydraulic system becomes easier.

Further, by adopting the connecting structure of the piston rod of the mold opening / closing piston and the mold clamping force transmitting rod on the movable plate side shown in the embodiment, the connecting work between the two can be easily performed. .

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing a mold clamping state of a first embodiment.

FIG. 2 is a side view showing the mold open state of the first embodiment.

FIG. 3 is a front view showing the lock mechanism of the first embodiment.

FIG. 4 is an enlarged side view of the rod tip of the mold opening / closing cylinder.

FIG. 5 is an enlarged front view of the rod tip of the mold opening / closing cylinder.

FIG. 6 is an enlarged cross-sectional view of the tip of the mold clamping force transmission rod.

FIG. 7 is an enlarged front view of the tip of the mold clamping force transmission rod.

FIG. 8 is an enlarged sectional view showing a connecting structure of a piston rod and a mold clamping force transmission rod.

FIG. 9 is a partial cross-sectional side view of a main part showing another example of the lock mechanism.

FIG. 10 is a view on arrow A in FIG.

FIG. 11 is a view on arrow A of FIG. 9 showing another structural example.

FIG. 12 is a partial cross-sectional side view showing the main part of the second embodiment.

[Explanation of symbols]

 2 Movable plate 3 Support plate 8 Mold clamping force transmission rod 9 Male spline 10 Mold clamping cylinder 11 Mold clamping piston 12 Through hole 16 Female spline 21 Lock cylinder 24 Lock device 25 Mold opening / closing cylinder 26 Piston rod 37 Mold clamping force transmission plate 38 Notch 39 Oscillating cylinder 40 Direct acting cylinder 43 Locking block 49 Insertion port 50 Engaging groove 53 Stopper pin 55 Set screw

Claims (4)

[Scope of utility model registration request] 1. A mold clamping cylinder (1) is provided with a mold clamping cylinder (10) and a mold opening / closing cylinder (25) individually on a support board (3).
In a mold clamping device equipped with a lock mechanism that selectively transmits the thrust of (0) to the movable platen (2), the mold clamping cylinder (10) is formed in a ring shape at the center of the support plate (3), and the mold clamping piston The clamping force transmission rod is located at the axis of (11).
There is a through hole (12) through which (8) can pass, the mold opening and closing cylinder (25) is located at the axis of the mold clamping cylinder (10), and the piston rod ( The mold of the injection molding machine is characterized in that the support plate (3) and the mold clamping force transmission rod (8) are connected to each other through the through hole (12) of the mold clamping piston (11). Fastening device. 2. The locking device (24) is a mold clamping force transmission rod.
A male spline (9) formed on the tip peripheral surface of (8) and a female spline (16) rotatably fitted to the mold clamping piston (11).
The mold clamping device according to claim 1, comprising a rotary drive device (21) for the female spline (16). 3. A mold clamping force transmitting plate (37) which is inserted between the tip of the mold clamping force transmitting rod (8) and the tip of the mold clamping piston (11) when the mold is closed. , This clamping force transmission plate (37)
And a drive device (39) or (40) for moving the mold clamping force transmitting plate (37) through which the piston rod (26) of the mold opening / closing cylinder can pass in the notch (38). The mold clamping device according to claim 1, further comprising: 4. A piston rod (2) of a mold opening / closing cylinder (25).
6) and the mold clamping force transmission rod (8) are connected by the piston rod.
An axisymmetric and non-circular locking block (43) fixed to the tip of (26) and an insertion opening opened at the tip of the mold clamping force transmission rod (8) in the same shape as the locking block (43). (49), a circular engagement groove (50) provided on the back side of the insertion block (43) connected to the insertion port (49) in a size such that the locking block (43) can rotate about the axis, and the insertion port. Locking block inserted into engagement groove (50) through (49)
The mold clamping device according to claim 1, 2 or 3, further comprising fixing means (53), (55) for fixing the rotation of the (43) at a position out of phase with the insertion opening (49).