JPH09193220A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mold clamping operation by high pressure contact force without lowering a mold opening and closing speed by a simple structure using an air cylinder in the mold opening and closing drive means opening and closing a fixed mold and a movable mold. SOLUTION: Tie bars 32, 32 pierce a movable plate 26 and the movable plate 26 is made freely separable from one fixed plate 24. A mold opening and closing drive means 29 is arranged between the movable plate 26 and other fixed plate 25 and uses a pair of air cylinders 33, 34. The air cylinders 33, 34 are same in constitution and arranged between the fixed plate 25 and the movable plate 26 up and down. The air cylinders 33, 34 consist of cylinders 35 and the rods 36 inserted into and drawn out of the cylinders 35 and the rear end part of the cylinder 35 is fixed to the other fixed plate 25 and the leading end parts of the rods 36 inserted into and drawn out of the cylinders 35 are connected to the movable plate 26.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an injection molding machine for molding a resin product.

[0002]

2. Description of the Related Art FIG. 9 shows an injection molding machine described in JP-A-61-106221. In the figure, the injection molding machine 1 includes a fixed platen 3 whose four corners are connected by four tie bars 2 and 2 (two of which are shown in the drawing),
The first and second rotating members 5 and 6, the first and second slide members 7 and 8, and the movable platen 9 are arranged between the stationary platen 4 and the stationary platen 4. A fixed die 10 is fixed to the fixed platen 3, and a movable die 11 that is brought into contact with and separated from the fixed die 10 is fixed to the movable platen 9.

The first rotating member 5 is rotatably supported by a cylindrical portion 12 projecting from the stationary platen 4 toward the movable platen 9 side, and a gear part 13 formed on the outer periphery of the first rotating member 5 has a gear wheel 14.
Are engaged. The gear 14 is fixed to the drive shaft of the motor 15. Further, the first rotating member 5 is provided with a long cylindrical portion 16 protruding toward the movable platen 9 side. A ball screw is formed on the outer periphery of the long cylindrical portion 16. Then, the first slide member 7 is engaged with the ball screw. A second rotating member 6 is rotatably supported on the outer circumference of the first slide member 7.

The second rotating member 6 has a gear portion 17 on the outer peripheral side.
And the longitudinal cylindrical portion 1 is formed toward the movable plate 9 side.
8 are formed. The long cylindrical portion 18 is rotatably supported by the second slide member 8. A gear 19 meshes with the gear portion 17. This gear 19
Are fixed to the drive shaft of the motor 20. Motor 20
Is fixed to the second slide member 8. Further, a ball screw is formed on the outer circumference of the long cylindrical portion 18. The cylindrical portion 21 meshes with the ball screw. The cylindrical portion 21 is formed integrally with the movable platen 9.

When the first rotating member 5 is rotated by the rotational driving of the motor 15, the first slide member 7 meshing with the ball screw of the longitudinal cylindrical portion 16 is fixed to the stationary platen 3.
Move to the side. When the first slide member 7 moves to the fixed platen 3 side, the second rotating member 6 moves to the fixed platen 3 side, and the movable platen 9 moves to the fixed platen 3 side. Thereby, the movable mold 11
Comes into contact with the fixed mold 10 and the mold is closed.

When the movable die 11 comes into contact with the fixed die 10, the motor 20 is rotationally driven this time. When the motor 20 is driven to rotate, the second rotating member 6 rotates, the cylindrical portion 21 that meshes with the ball screw of the longitudinal cylindrical portion 18 moves to the fixed platen 3 side, and the movable die 11 comes into close contact with and comes into contact with the fixed die 10. Contact. As a result, the mold clamping operation is performed.

In such an injection molding machine 1, the movable mold 11
The mold opening / closing operation for separating the movable mold 11 from the fixed mold 10 must be performed quickly until the abutting contact with the fixed mold 10, or after molding. Therefore, in the injection molding machine 1, the ball screw provided on the outer periphery of the long cylindrical portion 16 has a long thread pitch so that the first slide member 7 can quickly move to the fixed platen 3 side. It is like this.

On the other hand, the mold clamping force after bringing the movable mold 11 and the fixed mold 10 into contact with each other is sufficient as a pressure contact force against the injection resin pressure injected between the movable mold 11 and the fixed mold 10. The function of tightening is required. Therefore, the injection molding machine 1 described above
In the ball screw provided on the outer periphery of the long cylindrical portion 18, the pitch of the screw thread is set to be short so that high torque can be produced.

When the movable mold 11 and the fixed mold 10 are opened and closed, the motor 15 is driven to quickly open and close the mold.
The motor 2 is used when the movable mold 11 and the fixed mold 10 are clamped.
A high torque is generated by driving 0, and the movable die 11 and the fixed die 10 are brought into close contact with each other with a high pressure contact force.

[0010]

However, since the injection molding machine 1 uses the plurality of motors 15 and 20 and the ball screw, the number of parts is large and the structure is complicated. Further, a control mechanism for controlling the operations of the motors 15 and 20 is also required, which causes a problem of high manufacturing cost.

Therefore, Japanese Patent Application Laid-Open No. 1-326225 proposes an injection molding machine in which one motor and a pair of ball screws and nuts are used to perform a mold opening / closing operation and a mold clamping operation.

However, in this injection molding machine, if the pitch of the thread of the ball screw is lengthened to increase the mold opening / closing speed,
The required pressure contact force at the time of mold clamping cannot be obtained. Conversely, if the pitch of the thread of the ball screw is shortened to increase the pressure contact force at the time of mold clamping, the mold opening / closing speed becomes slow. For this reason, it is not possible to obtain a high mold opening / closing speed and to obtain a high pressure contact force at the time of mold clamping only with a pair of ball screws and nuts, and one of them is sacrificed. Further, if the pitch of the thread of the ball screw is shortened to obtain a high pressure contact force, the mold opening / closing speed is reduced and the molding cycle becomes long, resulting in high manufacturing cost.

It is therefore an object of the present invention to provide an injection molding machine having a simple structure and capable of performing a mold clamping operation with a high pressure contact force without lowering the mold opening / closing speed.

[0014]

In order to achieve the above object, the invention according to claim 1 has a pair of fixed plates fixed at a predetermined interval on a base and one of these fixed plates. A movable plate disposed so as to come in contact with and separated from a fixed plate; a fixed mold fixed to one of the fixed plates; a movable mold fixed to the movable plate so as to face the fixed mold; and the movable plate. Mold opening and closing drive means for opening and closing between the fixed mold and the movable mold by bringing the movable mold into and out of contact with one fixed plate side, and mold clamping for pressing the movable mold toward the solid mold and closely contacting the movable mold with the fixed mold. An injection molding machine having a mechanism, wherein an air cylinder is used as the mold opening / closing drive means.

In this injection molding machine, the movable platen is moved to one fixed platen side by operating the air cylinder to close the gap between the movable mold and the fixed mold. Next, the mold clamping mechanism presses the movable mold toward the solid mold to bring the movable mold into close contact with the fixed mold. In this state, for example, molten resin is press-fitted between the movable die and the fixed die to form a resin product. After molding the resin molded product, the mold clamping mechanism is deactivated, the air cylinder is activated, and the movable platen is separated from one fixed platen to open the space between the movable mold and the fixed mold, Take out the resin product.

In this resin molding machine, since the air cylinder is used as the mold opening / closing driving means for bringing the movable mold into and out of contact with the fixed mold, the structure becomes simple as compared with the mechanism using the motor, the ball screw and the nut. . Further, since the air cylinder is used as the mold opening / closing driving means, the mold opening / closing operation can be performed at high speed. Furthermore, since expensive ball screws and nuts are not used for the mold opening / closing operation, the cost is low. Further, even if the mold opening / closing speed is increased, the pressure contact force between the movable mold and the fixed mold does not decrease.

The invention of claim 2 is characterized in that the air cylinder is arranged between the other fixed plate and the movable plate.

In this injection molding machine, since the air cylinder is arranged between the fixed platen and the movable platen, there is no protrusion outside the space surrounded by the fixed platen and the movable platen. Can be downsized.

The third aspect of the present invention is the first or second aspect.
The injection molding machine described above is characterized in that a pair of the air cylinders is provided on the base in a vertical direction.

In this injection molding machine, a pair of air cylinders are provided above and below, so that the movable platen is stably brought into contact with and separated from one fixed platen.

According to a fourth aspect of the present invention, there is provided the injection molding machine according to the first to third aspects, wherein the mold clamping mechanism is rotatably supported by the other fixed plate, and the ball screw nut. A ball screw shaft that is screwed into the screw nut and moves in the axial direction by the rotation of the ball screw nut,
A motor that rotationally drives the ball screw nut and a movable plate that projects toward the other fixed platen side, and the end part of the ball screw shaft is housed when the movable platen is located on the other fixed platen side when the mold is opened. The stopper plate is provided at the other fixed plate side opening of the stopper cylinder and the stopper cylinder from which the end of the ball screw shaft is pulled out when the mold is closed when the movable plate is located on the one fixed plate side. And a shutter with which the front end of the ball screw shaft abuts when the movable platen is closed.

In this injection molding machine, the end of the ball screw shaft is housed in the stopper cylinder when the movable mold is separated from the fixed mold, and the end of the ball screw shaft is closed when the mold is closed. As the shutter closes the opening of the stopper cylinder and the end of the ball screw shaft abuts, the length between the pair of fixed plates can be shortened and the injection molding machine can be downsized. .

According to a fifth aspect of the present invention, in the injection molding machine according to the fourth aspect, the inner cylinder is inserted between the tip of the ball screw shaft and the shutter, into which the tip of the ball screw shaft is inserted. It is characterized in that it has a slide outer cylinder protruding from the other fixed plate toward the movable plate and supporting the outer periphery of the inner cylinder and supporting the tip end side of the ball screw shaft.

In this injection molding machine, the tip of the ball screw shaft is supported by the slide outer cylinder via the inner cylinder.

According to a sixth aspect of the present invention, there is provided the injection molding machine according to the third or fourth aspect, wherein the shutter includes a guide support frame provided around the opening of the stopper tube, and A pair of slide lids slidably supported by the guide support frame between the front side of the opening and a position retracted from the front side of the opening and capable of closing each half of the opening, and the slide lids are driven. It is characterized by comprising an air cylinder.

In this injection molding machine, by opening and closing the opening of the stopper cylinder with a pair of slide lids, the tip of the ball screw shaft abuts on the slide lid, and the movable plate is pressed toward the fixed plate through the stopper cylinder. Then, the mold clamping operation is performed. In this case, since the opening is opened and closed by the pair of slide lids, the opening can be opened and closed quickly.

The invention according to claim 7 is the injection molding machine according to any one of claims 4 to 6, wherein a speed change mechanism for transmitting the rotational driving force of the motor to the ball screw nut is provided between the motor and the ball screw nut. It is characterized by having means.

In this injection molding machine, since the rotation of the motor is transmitted to the ball screw nut while changing the speed, it is possible to generate high torque with a small motor.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an injection molding machine according to the present invention will be described below with reference to the drawings. 1 is a cross-sectional view showing the configuration of the injection molding machine 22, and FIG. 2 is a left side view of the injection molding machine 22 shown in FIG.

As shown in FIG. 1, the injection molding machine 22 includes a fixed plate 24 fixed on a base 23 at a predetermined interval.
25, a movable plate 26 disposed between these fixed plates 24, 25, and a fixed die 27 fixed to one fixed plate 25.
And a movable die 28 fixed to the movable plate 26 facing the fixed die 27, and the movable plate 26 is moved to one fixed plate 24 side to bring the movable die 28 into contact with the fixed die 27 and move the movable die 28. Mold opening / closing drive means 2 for separating the plate 26 from the fixed plate 24
9 and the movable die 28 toward the fixed die 27 to press the movable die 2
And a mold clamping mechanism 30 for bringing 8 into close contact with the fixed mold 27.

The fixing plates 24 and 25 are fixed on the base 23 with bolts 31 at predetermined intervals, and are connected by four tie bars 32 and 32 having four corners (only two tie bars are shown in the figure). It is fixed. These tie bars 32,
The numeral 32 penetrates the movable platen 26, which allows the movable platen 26 to come into contact with and separate from the fixed plate 24 on one side. A mold opening / closing drive means 29 is arranged between the movable platen 26 and the other fixed platen 25.

The mold opening / closing drive means 29 comprises a pair of air cylinders 33 and 34. The air cylinders 33 and 34 have the same structure, and are arranged above and below the fixed plate 25 and the movable plate 26, respectively. The air cylinders 33 and 34 include a cylinder 35 and a rod 3 that is inserted into and removed from the cylinder 35.
6 and the rear end of the cylinder 35 is the other fixed plate 2
5 is fixed to the rod 35 and is inserted into and removed from the cylinder 35.
Is connected to the movable plate 26. When the rod 36 is inserted into the cylinder 35, the movable platen 26 is separated from the fixed platen 25 and positioned on the fixed platen 24 side, the movable mold 28 and the fixed mold 27 are separated from each other, and the mold is opened. .
Further, when the rod 36 projects from the inside of the cylinder 35, the movable platen 26 is positioned on the other fixed platen 25 side, and the movable mold 28 and the fixed mold 27 come into contact with or come close to each other to be in a mold closed state.

Compressed air is supplied into the cylinders 35 of the air cylinders 33 and 35 by a compressed air supply means (not shown). By changing the pressure of the compressed air, it is possible to change the protruding speed of the rod when protruding from the inside of the cylinder 35 and the insertion speed of the rod when inserting into the cylinder 35.

A shock absorber 67 is fixed on the base 23 between the movable plate 26 and the other fixed plate 25. The shock absorber 67 contacts the movable platen 26 to set the mold opening position of the movable platen 26, and the movable plates 2 are moved by the operation of the air cylinders 33 and 35.
The shock when the 6 moves to the other fixed platen 25 side and stops is buffered.

The mold clamping mechanism 30 includes a ball screw nut 37 rotatably supported on the other fixed platen 25, and a ball screw shaft 38 which is screwed into the ball screw nut 37 and moves in the axial direction by the rotation of the ball screw nut 37.
And a motor 39 for driving the ball screw nut 37 to rotate.
And a stopper cylinder 40 projecting from the movable plate 26 toward the other fixed plate 25 side, and a shutter 42 provided in an opening 41 on the other fixed plate 25 side of the stopper cylinder 40.

In the mold clamping mechanism 30, the tip portion 38a of the ball screw shaft 38 is inserted and the inner cylinder 43 arranged between the tip portion 38a of the ball screw shaft 38 and the shutter 42 and the stationary platen 25 on the other side. And a slide outer cylinder 44 that protrudes toward the movable plate 26 side and that supports the outer circumference of the inner cylinder 43 and supports the tip 38a side of the ball screw shaft 38.

The ball screw nut 37 is integrally assembled with the sleeve 45. The sleeve 45 is rotatably supported on the inner wall of the support hole 47 via bearings 46, 46. The support holes 47 are provided in the fixed platen 25 so as to penetrate through the front and back. Further, it is provided on the outer side of the fixed platen 25 between the ball screw nut 37 and the motor 39, and the rotational driving force of the motor 39 is applied to the ball screw nut 37.
There is provided a speed changing means 66 for transmitting to the.

The speed changing means 66 includes large diameter gears 48, 51.
And small gears 49 and 52. As shown in FIGS. 1 and 2, the gear 45 is integrally fixed to the outside of the other fixed platen 25 on the sleeve 45 to which the ball screw nut 37 is assembled. A gear 49 having a smaller diameter than that of the gear 48 meshes with the gear 48. Small diameter gear 49
Is fixed to a rotary shaft 50 that is provided to project outward from the other fixed platen 25 and is rotatably supported.

A gear 51 having a larger diameter than the gear 49 and a smaller diameter than the gear 48 is fixed to the rotary shaft 50. A small-diameter gear 52 meshes with the gear 51. The small-diameter gear 52 is fixed to a rotary shaft 53 that is rotatably supported by the other stationary platen 25. A pulley 54 is fixed to the rotary shaft 53, and an endless belt 55 is wound around the pulley 54 and a pulley 64 fixed to a drive shaft 39a of the motor 39. The motor 39 is the base 23
It is fixed to the bottom side of the.

Then, the rotational driving force of the motor 39 is transmitted to the rotary shaft 53 via the endless belt 55, and the gear 52,
Transmitted to the sleeve 45 via 51, 49, 48,
The ball screw nut 37 rotates. Ball screw nut 3
When 7 rotates, the ball screw shaft 38 screwed into the ball screw nut 37 moves in the axial direction. In this case, depending on the rotation direction of the motor 39, the ball screw shaft 3
8 moves in the left-right direction in FIG. 1, that is, in the direction toward and away from the fixed platen 24.

A step portion 56 is formed at the end of the ball screw shaft 38 on the movable plate 26 side, and the tip end portion is formed to have a small diameter. A step 57 formed on the inner wall of the inner cylinder 43 is in contact with the step 56.

The inner cylinder 43 is inserted into a slide outer cylinder 44 fixed to the other fixed platen 25. Also, the inner cylinder 4
A slide key 59 is provided between the slide outer cylinder 44 and the inner wall of the slide outer cylinder 44 to restrict rotation of the inner cylinder 43 with respect to the slide outer cylinder 44. Therefore, even if the ball screw shaft 38 rotates, the inner cylinder 43 does not rotate with the rotation. Further, the slide outer cylinder 44 supports the inner cylinder 43, thereby supporting the end portion of the ball screw shaft 38.

On the other hand, a shutter 42 is arranged in an opening 41 on the fixed plate 25 side of a stopper cylinder 40 provided on the movable plate 26. This shutter 42, as shown in FIG.
A rectangular guide support frame 60 provided around the opening 41 of the stopper tube 40, and the opening 41 in the guide support frame 60.
A pair of slide lids 61, 62 slidably supported between the front side of the opening 41 and a position retracted from the front side of the opening 41 and capable of closing each half of the opening 41, and the slide lids 61, 62. A pair of driven air cylinders 63, 63
Consists of Further, arcuate notches 61a and 62a are formed on the mating surfaces of the slide lids 61 and 62, respectively. The inner diameters of the notches 61a and 62a are slightly larger than the outer diameter of the ball screw shaft 38 and smaller than the outer diameter of the inner cylinder 43. The inner diameter of the stopper cylinder 40 is set to be larger than the outer diameter of the slide cylinder 44 so that the end of the slide cylinder 44 can be accommodated in the stopper cylinder 40.

When the movable platen 26 is located on the other fixed platen 25 side and the mold is open, as shown in FIG. 4A, the shutter 42 is open and the end of the slide cylinder 44 is a stopper cylinder. It is inserted in 40. Also, movable plate 2
When 6 is in the mold closed state, which is located on the side of one fixed plate 24,
As shown in FIG. 4B, the shutter 42 is in a closed state, and the end surface 43a of the inner cylinder 43 abuts around the notches 61a and 62a of the slide lids 61 and 62.

In this state, the driving force of the motor 39 causes the ball screw shaft 38 to press the inner cylinder 43 toward the slide lids 61, 61, whereby the stopper cylinder 40 is pressed.
When the stopper cylinder 40 is pressed, the movable platen 26 is pressed toward one of the fixed plates 24, so that the movable mold 28 comes into close contact with the fixed mold 27 with a predetermined pressing force, and the mold clamping operation is performed.

Behind the slide cylinder 44, the movable platen 2
An eject mechanism 65 is formed at 6 to face the tip portion 38 a of the ball screw shaft 38. The eject mechanism 65 includes a push pin 65a capable of projecting to the movable die 28 side and an abutment plate 65b integrally formed on the stopper cylinder 40 side of the push pin 65a, and the end surface of the tip portion 38a of the ball screw shaft 38 is Upon contact, the push-out pin 65a projects into the movable die 28 to push out the resin molded product in the movable die 28.

Next, the operation of the injection molding machine 22 of this embodiment will be described.

In the fixed position state shown in FIG. 5, the movable platen 26 is positioned on the other fixed platen 25 side, and the shock absorber 67 is provided.
And the movable die 28 is separated from the fixed die 27.
Further, in this state, the rods 36 of the air cylinders 33 and 34 are inserted into the cylinder 35. Further, the slide lids 61 and 62 of the shutter 42 are opened, and the end portion of the slide cylinder 44 is inserted into the stopper cylinder 40.

From this state, the air cylinders 33 and 34 are operated and the rod 36 is projected from the inside of the cylinder 35. When the rod 36 is projected from the cylinder 35, as shown in FIG.
As shown in FIG. 5, the movable platen 26 moves to the one fixed platen 24 side, and the movable mold 28 abuts the fixed mold 27 to be in the mold closed state. In this state, as shown in FIG.
The end portion of is pulled out from the stopper tube 40. And
The air cylinder 63 of the shutter 42 is operated, and the opening 41 of the stopper tube 40 is closed by the slide lids 61 and 62.

Next, by driving the motor 39 to rotate the ball screw nut 37, the ball screw shaft 3
8 is moved to the movable plate 26 side. Ball screw shaft 3
When 8 moves to the movable platen 26 side, the inner cylinder 43 moves to the movable platen 26.
And the end surface 43a of the inner cylinder 43 is moved to the slide lid 6
It abuts around the notches 61a and 62a of the first and the second 62. After the end surface 43a of the inner cylinder 43 comes into contact with the slide lids 61 and 62, the end surface 43a of the inner cylinder 43 is further slid through the ball screw shaft 38 by driving the motor 39.
When pressed toward 62, the movable platen 26 is pressed to the fixed platen 24 side, the movable mold 28 is pressed against the fixed mold 27 side, and the mold clamping operation is performed.

Then, from this state, the molten resin is press-fitted between the fixed die 27 and the movable die 28 by a resin supply device (not shown). The mold clamping force between the movable mold 28 and the fixed mold 27 is set to be larger than the resin pressure at this time. After the molten resin is supplied between the fixed die 27 and the movable die 28, the motor 39 is rotated in the reverse direction so that the fixed die 27 of the movable die 28 is rotated.
Release the pressure contact condition to and release the mold clamping operation. next,
The air cylinder 63 is operated to move the slide lids 61 and 62, and the opening 41 of the slipper cylinder 40 is opened.

From this state, the air cylinders 33 and 34 are operated to move the movable platen 26 to the other fixed platen 25 side, and the movable platen 26 is separated from the fixed platen 24, so that the mold is opened. At the same time, as shown in FIG.
The motor 39 is driven to move the ball screw shaft 38 to the movable platen 26 side, and the eject mechanism 65 is operated to push out the product formed on the movable mold 28 from the movable mold 28 by the push pin 65a.

When the movable platen 26 moves to the fixed position,
The end of the slide outer cylinder 44 is inserted into the stopper cylinder 40 together with the inner cylinder 43 and the tip portion 38a of the ball screw shaft 38. At the same time, the motor 39 is rotated in the reverse direction to move the ball screw shaft 38 in the reverse direction, that is, the other fixing plate 25.
Then, the operation of the eject mechanism 65 is stopped. This returns to the initial state shown in FIG. By repeatedly operating the above cycle, resin products are continuously molded.

In the injection molding machine 22 of this embodiment, the movable plate 26 is
In the case of moving the mold to the stationary platen 24 side to perform the mold closing operation, since the air cylinders 33 and 34 are used, the manufacturing cost can be reduced as compared with the case of using the ball screw nut and the ball screw shaft.

The air cylinder 3 is used as a mold opening / closing means.
By using 3, 34, the structure is simplified and its operation can be easily controlled. Further, the movable platen 26 can be stably brought into contact with and separated from the fixed platen 24 by using the pair of air cylinders 33 and 34. Further, the air cylinders 33 and 34 are attached to the fixed plate 25 and the movable plate 2.
Since it is arranged between the fixed plate 25 and the movable plate 2,
Since there is no protrusion outside the space surrounded by 6, the injection molding machine 22 can be downsized.

Further, by using the air cylinders 33 and 34, when the movable platen 26 is moved to the fixed platen 24 side, it can be moved quickly, the mold opening / closing time can be shortened, and the molding cycle can be shortened. Since the length can be shortened, it is possible to reduce the manufacturing cost when molding the resin product.

Further, in the injection molding machine 22 of the present embodiment, since the mold opening / closing operation is driven by the air cylinders 33, 34, the pitch of the screw threads of the ball screw nut 37 and the ball screw shaft 38 for performing the mold clamping operation is lengthened. Since it is not necessary to set it, and it can be set short, a high pressure contact force can be obtained.

In this embodiment, the motor 39, the ball screw nut 37 and the ball screw shaft 3 are used only for the mold clamping operation.
8 and the air cylinders 33 and 34 are used for the mold opening / closing operation, the control becomes simple and the maintenance becomes easy.

Furthermore, since the rotational driving force of the motor 39 is transmitted to the ball screw nut 37 via the speed changing means 66, a high torque can be generated by a small motor. Therefore, the size of the injection molding machine can be reduced also by this.

In the above embodiment, as the mold clamping mechanism 30, the ball screw shaft 38, the ball screw nut 37,
Although the motor 39 is used, a mold clamping mechanism of another form may be used.

[0061]

As described above, according to the first aspect of the invention, since the air cylinder is used for the mold opening / closing operation for bringing the movable mold into and out of contact with the fixed mold, a mechanism using a motor, a ball screw and a nut is used. Compared with, the structure is simpler and the manufacturing at low cost becomes possible. Further, the mold opening / closing operation can be performed at high speed by using the air cylinder as the mold opening / closing driving means. Further, even if the mold opening / closing speed is increased, the mold clamping operation can be performed with a high pressure contact force without lowering the pressure contact force.

According to the second aspect of the invention, since the air cylinder is arranged between the fixed plate and the movable plate, there is no protrusion outside the space surrounded by the fixed plate and the movable plate. Therefore, the molding machine can be downsized.

According to the third aspect of the invention, since the pair of air cylinders is provided above and below, the movable plate can be brought into and out of contact with one fixed plate in a stable manner.

According to the invention of claim 4, the end of the ball screw shaft is accommodated in the stopper cylinder when the movable mold is separated from the fixed mold and is opened, and when the mold is closed, the end of the ball screw shaft is closed. Is removed from the stopper cylinder, the shutter closes the opening of the stopper cylinder and the end of the ball screw shaft abuts, so that the distance between the pair of fixed plates can be shortened, and the injection molding machine can be downsized. .

According to the fifth aspect of the present invention, since the tip of the ball screw shaft is supported by the slide outer cylinder via the inner cylinder, the movable plate is surely pressed to one fixed plate side during the mold clamping operation. You can do it.

According to the sixth aspect of the invention, the opening of the stopper tube can be quickly opened and closed by simultaneously operating the pair of slide lids.

According to the seventh aspect of the invention, the rotation of the motor is transmitted to the ball screw nut while changing the speed, so that it is possible to generate a high torque with a small motor.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of an injection molding machine according to the present invention.

FIG. 2 is a front view showing the relationship between the motor of the injection molding machine and the ball screw shaft as seen from the direction of arrow P in FIG.

FIG. 3 is a partially cutaway perspective view showing a relationship between a tip portion of a ball screw shaft, a shutter, and a stopper cylinder.

FIG. 4 is a front view showing the operation of the shutter, in which (a) is a front view showing a state in which the opening of the stopper tube is opened, and (b) is a front view showing a state in which the opening section of the stopper tube is closed.

FIG. 5 is a partially cutaway side view showing the mold open state.

FIG. 6 is a side view showing a mold closed state.

FIG. 7 is a partially cutaway side view showing a state where the mold clamping mechanism is operated.

FIG. 8 is a side view showing a state in which a mold opening operation and an ejector mechanism are activated.

FIG. 9 is a sectional view showing a conventional injection molding machine.

[Explanation of symbols]

 22 injection molding machine 23 base 24, 25 fixed plate 26 movable plate 27 fixed type 28 movable type 29 mold opening / closing drive means 30 mold clamping mechanism 33, 34 air cylinder 37 ball screw nut 38 ball screw shaft 38a tip portion 39 motor 40 stopper shaft 41 Opening 42 Shutter 43 Inner cylinder 44 Slide outer cylinder 61, 62 Slide lid

Claims (7)

[Claims] 1. A pair of fixed plates fixed on a base at a predetermined interval, a movable plate arranged between these fixed plates so as to come into contact with and separate from one fixed plate, and one. Fixed type fixed to the fixed plate, a movable type fixed to the movable plate facing the fixed type, and a fixed type and a movable type by moving the movable plate to and from one fixed plate. An injection molding machine comprising: a mold opening / closing drive means for opening and closing a space between the mold and a mold clamping mechanism for pressing the movable mold toward the solid mold to bring the movable mold into close contact with the fixed mold. An injection molding machine characterized by using. 2. The injection molding machine according to claim 1, wherein the air cylinder is arranged between the other fixed plate and the movable plate. 3. The injection molding machine according to claim 1 or 2, wherein a pair of the air cylinders are provided on the base in a vertical direction. 4. The injection molding machine according to claim 1, wherein the mold clamping mechanism is a ball screw nut rotatably supported by the other fixed plate, and the ball. A ball screw shaft that is screwed into the screw nut and moves in the axial direction by the rotation of the ball screw nut, a motor that drives the ball screw nut to rotate, and a movable plate that protrudes toward the fixed plate side of the other movable plate. One end of the ball screw shaft is accommodated when the mold located on the other fixed plate side is opened, and the other end of the ball screw shaft is pulled out when the mold is closed when the movable plate is located on the one fixed plate side. A shutter provided in the opening on the other side of the fixed plate, which opens when the mold of the movable plate is opened and closes when the mold of the movable plate is closed so that the tip of the ball screw shaft abuts. An injection molding machine characterized by comprising: 5. The injection molding machine according to claim 4, wherein an inner cylinder, into which the tip of the ball screw shaft is inserted, is arranged between the tip of the ball screw shaft and the shutter, and a stationary plate on the other side. And a slide outer cylinder which is provided so as to project toward the movable plate side and which supports the outer circumference of the inner cylinder and supports the tip end side of the ball screw shaft. 6. The injection molding machine according to claim 4, wherein the shutter has a guide support frame provided around the opening of the stopper cylinder, and an opening formed in the guide support frame. A pair of slide lids slidably supported between the front side of the and the position retracted from the front side of the opening and capable of closing each half of the opening, and an air cylinder for driving the slide lid. An injection molding machine characterized by. 7. The injection molding machine according to claim 4, further comprising: a speed change device for transmitting the rotational driving force of the motor to the ball screw nut between the motor and the ball screw nut. And injection molding machine.