JP3524621B2 - Mold clamping device of injection molding machine - Google Patents

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 for a mold clamping tie bar of an injection molding machine.

[0002]

2. Description of the Related Art Generally, in a mold clamping device of an injection molding machine, a large mold clamping force is required during mold clamping in order to prevent the mold from opening due to the pressure in the mold during injection. It is required to open the mold as quickly as necessary when removing the product. The hydraulic drive source is downsized, the operation speed is increased, the manufacturing cost and the operating cost are reduced, and the die movement and the die clamping are not performed by a single hydraulic cylinder, but the hydraulic cylinder with a small diameter and a long stroke is used. Open and close the mold,
A method of clamping a movable die plate by applying a strong pressure to a fixed die plate by another plurality of large-diameter, short-stroke mold clamping cylinders has been implemented.

FIG. 5 is a vertical sectional view showing a typical structure of such a mold clamping device. Reference numeral 10 is a support frame, and a fixed die plate 14 to which a fixed mold 12 is attached is fixed to one end of the support frame. At the other end of the support frame 10, a movable die plate 18 to which a movable die 16 is attached is movably placed so as to face the fixed die plate 14. The fixed die plate 14 is provided with a plurality of hydraulic cylinders 20,
A tie bar 24 is directly connected to one side surface of a piston 22 that slides in the hydraulic cylinder 20.
Penetrates through the insertion hole 36 of the moving die plate 18 which is opposed to the movable die plate 18, and the tip end thereof is connected and fixed to the support plate 26. A movable cylinder 28 is fixed to one side of the fixed die plate 14, and the tip of a rod 32 directly connected to the piston 30 inside the movable cylinder 28 is appropriately fixed to the side surface of the movable die plate 18. A part of the tie bar 24 has a threaded portion 34 formed therein, and the insertion hole 3 through which the tie bar 24 is inserted.
On the side of the moving die plate 18 close to 6, the tie bar 2
A half nut 38 that meshes with the screw portion 34 of No. 4 is provided so as to be movable in the direction perpendicular to the axis of the insertion hole 36. A shaft 40 penetrating the support plate 26 is provided at the center of the movable die plate 18, and a stop ring 42 is provided at the tip of the shaft 40 so that its axial position can be adjusted. That is, the shaft 40 is appropriately provided with a plurality of circumferential grooves 44 for changing the position of the stop ring 42.

In the mold clamping device of this structure, first, the movable die plate 18 is fixed to the fixed die plate 1 by the moving cylinder 28.
Move to 4 side. Immediately before the mold closing of the fixed mold 12 and the movable mold 16 is completed, the stop ring 42 positioned on the shaft 40 protruding from the movable die plate 18 engages with the support plate 26. At this time, the half nut 38 is moved and screwed into the thread portion 34 of the tie bar 24. Next, pressure oil is supplied to the hydraulic cylinder 20, the moving die plate 18 is moved to the fixed die plate 14 side via the tie bar 24, and the fixed die 12 and the moving die 16 can be clamped.

In the above-mentioned conventional example, the movement of the mold is not shared by the single hydraulic cylinder, but the function is divided between the opening / closing cylinder and the other multiple short-stroke mold clamping cylinders. Although the mold clamping device is downsized and the installation area is saved, the injection molding machine tends to increase in size, and various proposals have been made to further reduce the structure.
FIG. 6 shows an example proposed in Japanese Patent Application Laid-Open No. 60-82309. In this example, the shaft 40 protruding from the central portion of the movable die plate 18 and the tie bar 24 in the above-mentioned conventional example. Plate 26 fixed to the end of the
The length of the mold clamping device is shortened by changing the locking means of the moving die plate 18 constituted by and so as to be able to perform around the insertion hole 36 of the moving die plate, and its outline will be described.

In FIG. 6, 50 is a support frame, and 5
Reference numeral 4 is a fixed die plate to which a fixed mold 52 is attached.
Reference numeral 58 is a moving die plate to which the moving die 56 is attached. The fixed die plate 54 has a plurality of hydraulic cylinders 60.
A tie bar 64 is directly connected to one side of the piston 62 that slides in the hydraulic cylinder 60. A moving cylinder 66 is fixedly provided on one side of the fixed die plate 54, and the tip of a rod 70 directly connected to the piston 68 inside the moving cylinder 66 is appropriately fixed to the side surface of the moving die plate 58. A part of the tie bar 64 forms a threaded portion 72, and a half nut 76 that meshes with the threaded portion 72 of the tie bar 64 is provided on the side surface of the moving die plate 58 provided with an insertion hole 74 through which the tie bar 64 is inserted. It is provided so as to be movable in a direction perpendicular to the axis of the insertion hole 74.

The structure up to this point is the same as that of the mold clamping device of the first conventional example, but the locking means at the open limit of the moving die plate 58 is changed from the stroke limit of the moving cylinder 66. In the mold open state of the movable die plate 58, each dimension is set so that the tip of the tie bar 64 slightly enters the insertion hole 74 of the movable die plate 58, and the position of the stop ring 78 can be adjusted on a part of the tie bar 64. It is provided. In the standby state of the tie bar 64, the tie bar 64 is moved immediately before the movable die plate 58 moves and the fixed die 52 and the movable die 56 complete the die closing.
A stop ring 78 provided on the die lock surface of the movable die plate 58 on the die mounting surface side of the insertion hole 74, and the tie bar 64
The threaded portion 72 provided on the moving die plate 58 and the half nut 76 provided on the movable die plate 58 are positioned so as to mesh with each other.

In the mold clamping device having this structure, the movable die plate 58 is first moved to the fixed die plate 54 side from the opened state by the movable cylinder 66. Immediately before the mold closing of the fixed mold 52 and the moving mold 56 is completed, the tie bar 64 is
The stop ring 78 provided at the position engages with the open end of the insertion hole 74 of the movable die plate 58. At this time, the half nut 76 is moved to mesh with the screw portion 72 of the tie bar 64. Next, pressure oil is supplied to the hydraulic cylinder 60, the movable die plate 58 is moved to the fixed die plate 54 side through the tie bar 64, and the fixed die 52 and the movable die 56 can be clamped.

[0009]

A hydraulic cylinder for directly driving a mold clamping tie bar of a conventional mold clamping device requires a maximum and minimum difference between the thicknesses of various molds to be used, even if the stroke is small. The cylinder volume increases,
It takes time to pressurize the hydraulic oil, and the space occupied by the mold clamping cylinder becomes too large.

In one of the injection molding methods, after the mold is closed, the mold is once opened and then the mold is re-clamped after injection. In the injection compression molding process of injection molding, a half nut engages the mold tie bar. When locking, the stop ring provided on the tie bar engages with the open end of the insertion hole of the movable die plate, and then the half nut is moved to mesh with the threaded portion of the tie bar. After that, a dimensioning process using the hydraulic cylinder 60 is required, so that extra time is required for the mold clamping process and the process time becomes long.

[0011]

In order to solve the above problems, a fixed die plate for holding a fixed die, a movable die plate for holding a movable die, and a movable die plate for advancing and retracting with respect to the fixed die plate. A tie bar that has a moving means for operating and a means for connecting and fixing the moving die plate and the fixed die plate after the moving die plate approaches the fixed die plate and the fixed die and the moving die are closed. In the mold clamping device, the coupling and fixing means is provided on the surface of the moving die plate opposite to the mold mounting surface and is movable substantially at right angles to the axis of the tie bar insertion hole, and the tie bar is movable. Half nuts that perform positioning operations in both mold opening and closing directions and half nuts that are provided on the outer periphery of the tip of the tie bar that is directly connected to the ram of the mold clamping cylinder built into the fixed mold. It is composed of a threaded portion that meshes with each other or a plurality of ring grooves with an equal pitch, and a detecting means for detecting the relative position between the moving die plate and the tie bar, and a signal from the detecting means to stop the moving die plate at a predetermined position. The moving die press is performed by the hydraulic cylinder that is the moving means.
The tie bar when moving the
-Phase matches the screw (or ring groove) of the half nut
Clamp the mold so that the tie bar position is moved in advance.
It is characterized by having a control device for controlling the operation of the cylinder .

Further, in the above mold clamping device, the relative position detecting means for the moving die plate and the tie bar is a position sensor fixed to the tie bar, and a detecting graduation groove or a detecting graduation magnet attached to the moving die plate in the moving direction. When the moving die plate is moved by the moving cylinder, the relative position between the moving die plate and the tie bar is detected by the number of scales detected from the reference position of the scale by the position sensor, and a control device is provided. Move with the moving cylinder while collating with the designated position value entered in
When the moving die plate is moved to the position just before the completion of mold closing
The tie bar and half nut screw (or ring groove)
Move the position of the tie bar in advance so that the phases match.
Operate the mold clamping cylinder and place the tie bar at the required position.
You may make it have a function to stop. Again
In the above mold clamping device, the moving die plate and the tie bar
The relative position detection means is attached to the moving die plate.
The thread part of the tie bar or multiple ring groove parts of equal pitch.
It is a position sensor that detects the position in the controller.
Transfers the detection signal of the sensor to the phase of the moving die plate and tie bar.
Move die play by counting from the reference position
The specified position that is detected by detecting the position of the
Move the die plate with the moving cylinder while checking the value.
When moving to the position just before the mold closing is completed,
-The phase matches the screw (or ring groove) of the shaft nut.
To move the tie bar in advance.
Activate the cylinder and stop the tie bar at the required position
You may make it have a function.

[0013]

According to the present invention, by the above means, the mold clamping ram is positioned at the pushing end of the tie bar before the operation of the injection molding machine.
Operate the moving cylinder manually to move the moving die plate, stop the moving die plate at the mold open position calculated by the predetermined mold thickness, and detect the position by the position detection means (position sensor and scale). , The mold opening reference position is designated and stored in the control device. Next, the moving cylinder moves the moving die plate in the mold closing direction, the moving die plate approaches the fixed die plate, and the mutual screw or ring groove is engaged so that the tie bar can be connected to the half nut. The position detecting means detects the scale along the stroke, counts it, and stores the count number of the position in the control device.

In the mold clamping process during the operation of the machine, the position detecting means and the control device automatically move the die plate to the position immediately before the completion of the mold closing, and the half nut is engaged with the screw or ring groove of the tie bar. After coupling, pressure oil is sent to the hydraulic cylinder in the fixed die plate to raise the pressure and clamp the die. When releasing the mold, pressure oil is applied to the head side of the mold clamping cylinder to release the mold while the half nut is closed in the required range of force. After that, the half nut is opened to release the connection with the tie bar, and the moving cylinder is used to open the mold. The movable die plate is completely opened and stopped at a predetermined position by the action of the position detecting means and the control device.

[0015]

Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a mold clamping device of an injection molding machine according to an embodiment of the present invention, and FIG. 2 is a side view of FIG. Figure 3
FIG. 4 is an enlarged view of a relative position detection unit between the moving die plate and the tie bar of the mold clamping device of FIG. 1, and FIG. 4 is an enlarged view of another example of the relative position detection unit between the moving die plate and the tie bar. .

Reference numeral 1 is a support frame, and a fixed die plate 5 to which a fixed mold 3 is attached is fixed to one end of the support frame.
At the other end of the support frame 1, a movable die plate 9 having a movable die 7 attached is movably mounted so as to face the fixed die plate 5. Reference numeral 39 is a rail fixed to the support frame, and a linear bearing 35 guided by the rail 39 supports the movable die plate 9 via a base 37. The fixed die plate 5 is provided with a plurality of mold clamping cylinders 11 each having a smaller stroke and a smaller volume than the conventional example (four in this example), and the mold clamping ram 13 sliding in the hydraulic cylinder 11 has one side surface. The tie bar 15 is directly connected to
The tie bar 15 is held by penetrating the insertion hole 27 of the movable die plate 9 which faces the tie bar 15. Fixed die plate 5
A moving cylinder 17 is fixedly installed on one side of the rod 23. The rod 23 is directly connected to the piston 21 inside the moving cylinder 17.
Is fixed to the side surface of the movable die plate 9 as appropriate.
A part of the tie bar 15 forms a threaded portion 15a or a ring groove portion, respectively, while the side surface of the moving die plate 9 near the insertion hole 27 through which the tie bar 15 is inserted has a tie bar 1
A pair of half nuts 29 that mesh with the threaded portion 15a of No. 5 or the ring groove portion is provided movably in a right angle direction so as to be sandwiched by the cylinder 31 with respect to the axis of the insertion hole 27. The left half, which is partitioned by the center line BB in FIG. 2, shows the state in which the half nut 29 is open and the tie bar 15 is free, and the right half is that the cylinder 31 operates and the half nut 2 is open.
9 shows the state in which 9 is closed and engaged with the tie bar 15 to fix it. Reference numeral 33 is a support member that supports the half nut 29 when hydraulic pressure acts on the head side of the mold clamping ram 13 of the tie bar 15 with the half nut 29 closed and the tie bar is pushed leftward in FIG. Reference numeral 19 represents an injection cylinder. The chain double-dashed line in FIG. 1 shows the position of the movable die plate 9 when the mold is closed.

FIG. 3 shows the movable die plate 9 and the tie bar 15.
The enlarged view of the relative position detection part with is shown. 43 is a tie bar 1
5 is a proximity position sensor, and 47 is a detection graduation groove or detection graduation magnet 47 attached to the moving die plate 9.
is a scale with a. In the control device (not shown), the detection position at the fully open limit of the movable die plate 9 (the end surface of the movable die plate 9 is at the position S) is used as a reference point,
A moving distance m of the moving die plate 9 from the reference point to a position just before the molds 3 and 7 come into close contact with each other until the half nut 29 meshes with the screw 15a of the tie bar 15 (or the ring groove 25a) is calculated in advance. The number of scales corresponding to the position C of the moving die plate 9 that has moved the distance m is stored in the control device. While the movable die plate 9 is moving, a counter included in the control device records the number of graduations detected by the position sensor 43, and when this reaches the stored number of graduations, gives an instruction to stop the moving cylinder 17, The control circuit can control the moving cylinder 17 to stop at that position.

FIG. 4 shows an enlarged view of another example of the relative position detecting portion between the movable die plate and the tie bar. The tie bar 25 shows an example in which ring grooves 25a of equal pitch are provided (the screw 15a also has a similar function). In this case as well, similarly to the above, in the control device (not shown), the moving die plate 9
The detection position of the ring groove 25a at the full open limit S of is the reference point, and the position of the moving die plate 9 up to the position where the half nut 29 meshes with the ring groove 25a of the tie bar 25, slightly before the reference point, at which the die is in close contact. The moving distance m is calculated in advance, and the number of ring grooves corresponding to this moving distance m is stored in the control device. (At the position where the position sensor 41 detects the ring groove 25a and stops, the half nut 29 is at the tie bar 2
It is necessary to adjust the mounting position of the position sensor 41 with the adjusting plate 49 so that the position of the position sensor 41 is adjusted so as to be engaged with the screw 25a of No. 5. )
While the moving die plate 9 is moving, the counter of the control device records the number of ring grooves 25a (or the number of screw 15a grooves) detected by the position sensor 41, and when the number reaches the memorized scale number, the moving cylinder is moved. The control circuit can control the moving cylinder 17 to stop at that position by issuing an instruction to stop the moving cylinder 17. FIG. 4 shows a state in which the movable die plate 9 has moved a distance m and stopped at the position C.

The operation of this embodiment will be described. First, the mold clamping ram 13 is positioned at the pushing end of the tie bar 15 (the state of FIG. 4 shows this position), the moving cylinder 17 is operated, and the predetermined movement is performed. The movable die plate 9 is stopped at the mold open position calculated from the mold thickness (the inner surface of the movable die plate 9 shown by the solid line in FIG. 3 is at the position S), and the scale detected by the position sensor 43 at that time 47 scale 47a
The position is stored in a controller (not shown) as a relative reference position between the movable die plate 9 and the tie bar 15. Next, the moving cylinder 17 is actuated in the mold closing direction, and the half nut 29, slightly before the molds 3 and 7 come into close contact with the reference point, is moved.
Is the screw 15a of the tie bar 15 (or the ring groove 25
The moving distance m of the moving die plate 9 to the position meshing with a) is calculated in advance, and the number of graduations corresponding to this distance m is stored in the control device (the movement indicated by the chain double-dashed line in FIG. 3). The inner surface of the die plate 9 is at position C).

When the injection molding machine operates and enters the mold clamping process, the movable die plate 9 is stopped at the S position, and when a mold clamping command is issued, the movable die plate 9 is fixed by the operation of the movable cylinder 17. It approaches the die plate 5 and stops at the position C under the control of the controller. Here, the half nut 29 is screwed into the tie bar 15 (or the ring groove 25a).
Then, pressure oil is sent to the hydraulic cylinder 13 in the fixed die plate 5 to raise the pressure and clamp the die.

When the mold is released after the injection and cooling steps, while the half nut 29 is still connected to the tie bar 15, pressure oil is applied to the head side of the mold clamping ram 13 to push the movable mold 7 and release it. The mold is opened, the half nut 29 is opened to release the connection with the tie bar 15, the moving cylinder 17 is operated in the opposite direction to open the mold, and the molded product is taken out. When the screw 15a or the ring groove 25a of FIG. 4 is used as the scale to be detected, the operation is the same as above.

First, the mold clamping ram 13 is positioned at the pushing end of the tie bar 15, the moving cylinder 17 is operated, and the moving die plate 9 is moved to the mold opening position calculated by the predetermined mold thickness.
(In FIG. 4, the inner surface of the moving die plate 9 shown by the chain double-dashed line is at the position S), and the position sensor 4 at that time
The ring groove 25a detected by 1 is stored in a controller (not shown) as a relative reference position between the moving die plate 9 and the tie bar 25. Next, the moving cylinder 17 is actuated in the mold closing direction, and the half nut 29, which is located just before the molds 3 and 7 are in close contact with each other from the reference point, moves the ring nut 25 of the tie bar 25.
The moving distance m of the moving die plate 9 to the position meshing with a
Is calculated in advance, and the number of graduations corresponding to this distance m is stored in the control device (in FIG. 4, the inner surface of the movable die plate 9 indicated by the solid line is the position C).

When the injection molding machine operates and enters the mold clamping process, the movable die plate 9 is stopped at the S position, and when a mold clamping command is issued, the movable die plate 9 is fixed by the operation of the movable cylinder 17. It approaches the die plate 5 and stops at the position C under the control of the controller. Here, the half nut 29 is coupled to the ring groove 25a of the tie bar 25, and then pressure oil is sent to the mold clamping ram 13 in the fixed die plate 5 to raise the pressure and clamp the mold.

When the mold is released after the injection and cooling steps, the half nut 29 is kept connected to the tie bar 25, pressure oil is applied to the head side of the mold clamping cylinder 11, and the movable mold 7 is pushed and released. The mold is opened, the half nut 29 is opened to release the connection with the tie bar 25, the moving cylinder 17 is operated in the opposite direction to open the mold, and the molded product is taken out.

[0025]

As described above, the connecting and fixing means for connecting and fixing the moving die plate for holding the moving die and the fixed die plate for holding the fixed die are opposite to the die mounting surface of the moving die plate. Side nut, which is movable almost at right angles to the axis of the tie bar insertion hole and positions the tie bar in both directions of mold opening and closing, and the ram of the mold clamping cylinder built into the fixed mold. Since it is composed of a screw portion or a plurality of ring groove portions of equal pitch which mesh with the half nut provided on the outer periphery of the tip portion of the tie bar directly connected to, the volume of the mold clamping cylinder can be reduced and the boosting time can be shortened. Also, since the stop position of the moving die plate is automatically controlled, the end frame that supports the tip of the tie bar is not required, which contributes to space saving and cost reduction.
Furthermore, the relative stop position of the moving die plate with respect to the tie bar can be freely selected, so various mold thicknesses can be accommodated and the half nut and tie bar screw (or ring groove) can be used at any position.
This has the effect of facilitating compatibility with injection compression cloth pasting molding that requires the engagement of the above.

[Brief description of drawings]

FIG. 1 is a side view of a mold clamping device of an injection molding machine according to an embodiment of the present invention.

FIG. 2 is a side view of FIG. 1 taken along arrow A.

FIG. 3 is an enlarged view of a relative position detection unit between a moving die plate and a tie bar of the mold clamping device in FIG.

FIG. 4 is an enlarged view of another example of the relative position detection unit between the moving die plate and the tie bar.

FIG. 5 is a side sectional view showing a configuration example of a conventional mold clamping device.

FIG. 6 is a plan sectional view showing another configuration example of the conventional mold clamping device.

[Explanation of symbols]

3 fixed mold 5 Fixed die plate 7 Moving mold 9 Moving die plate 11 Mold clamping cylinder 13 Ram 15, 25 tie bar 17 Moving cylinder 29 Half Nut 41, 43 Position sensor 47 scale

Front page continuation (72) Inventor Saburo Fujita No. 1 Takamichi, Iwazuka-machi, Nakamura-ku, Nagoya, Aichi Prefecture Mitsubishi Heavy Industries, Ltd. Nagoya Machinery Works (72) Inventor Katsumi Nagasaki Iwatsuka, Nakamura-ku, Nagoya, Aichi Prefecture Highway No. 1 Mitsubishi Heavy Industries, Ltd. Inside Nagoya Machinery Works (72) Inventor Ryoichi Inoue 1 Kutabishi Engineering Co., Ltd., 60 Kutani Office, Iwatsuka-cho, Nakamura-ku, Nagoya-shi, Aichi (56) References Flat 4-18310 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B29C 45/66-45/68 B29C 45/76 B22D 17/26

Claims (3)

(57) [Claims] 1. A fixed die plate for holding a fixed die, a movable die plate for holding a movable die, moving means for moving the movable die plate forward and backward with respect to the fixed die plate, and the movable die plate. A mold clamping device comprising a tie bar for clamping a movable die plate and a fixed die plate after the fixed die plate and the movable die are closed by approaching the fixed die plate.
The coupling and fixing means is provided on the surface of the moving die plate opposite to the die mounting surface, and is movable substantially at right angles to the axis of the tie bar insertion hole, so that the tie bar can be positioned in both directions of mold opening and closing. Half nut, and a threaded portion or a plurality of ring groove portions of equal pitch that mesh with the half nut provided on the outer periphery of the tip portion of the tie bar directly connected to the ram of the mold clamping cylinder built in the fixed mold. , A detecting means for detecting the relative position between the moving die plate and the tie bar, and a hydraulic cylinder which is the moving means so as to stop the moving die plate at a predetermined position by a signal of the detecting means. When moving to the position of tie bar, move the position of tie bar beforehand so that the phase matches the screw (or ring groove) of the half nut and mold clamping. Mold clamping apparatus of an injection molding machine, characterized in that it comprises a control device for controlling the operation of the cylinder. 2. The mold clamping device according to claim 1, wherein a relative position detecting means for the movable die plate and the tie bar is fixed to the tie bar, and a detecting scale attached to the movable die plate in the moving direction. It is composed of a scale having a groove or a detection scale magnet, and when the moving die plate is moved by the moving cylinder, the relative position of the moving die plate and the tie bar is the number of scales detected from the reference position of the scale by the position sensor. When the moving die plate is moved to the position just before the completion of mold closing with the moving cylinder while detecting and collating with the designated position numerical value input in advance in the control device, the tie bar and half nut screw (or ring groove) and phase Operate the mold clamping cylinder to move the position of the tie bar in advance so that it matches, and stop the tie bar at the required position. A mold clamping device for an injection molding machine, which has a function. 3. The mold clamping apparatus according to claim 1, wherein the relative position detecting means between the moving die plate and the tie bar detects a screw portion of the tie bar attached to the moving die plate or a plurality of ring groove portions having an equal pitch. Is a position sensor,
The position of the moving die plate is detected by counting the detection signal of the position sensor in the control device from the relative reference position between the moving die plate and the tie bar, and the moving cylinder is collated with the designated position numerical value previously input to the control device. Move the moving die plate to the position immediately before the completion of mold closing. Move the tie bar in advance so that the tie bar and the half nut screw (or ring groove) are in phase. A mold clamping device for an injection molding machine, which has a function of operating and stopping a tie bar at a required position.