JP2665303B2 - Mold movement control device for hollow 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 moving device for a hollow molding machine.

[0002]

2. Description of the Related Art FIGS. 8 and 9 show a conventional mold moving device for a hollow molding machine. The mold moving device of the hollow molding machine shown in FIG.
The molten resin is extruded downward from the extruder 50 through the crosshead 52 as a cylindrical parison 54, and when the resin reaches a predetermined length, the hydraulic cylinder 60 is driven. The mold 58 in the mold open state waiting at the air blowing position indicated by the solid line is moved to the parison receiving position indicated by the imaginary line in the figure, and is closed and clamped by the mold clamping mechanism (not shown). The mold 58 sandwiching the parison 54 by the hydraulic cylinder 60
To move to the air blowing position indicated by the solid line in FIG. Thereby, the mold 5
8 is reciprocated between the air blowing position and the parison receiving position. The operation of the hollow molding machine is as follows. At the parison receiving position, the parison 54 sandwiched between the molds 58 is cut to a predetermined length by the parison cutting device 56, and the mold 5 is held in a state where the parison 54 is held.
8 is moved to the air blowing position as described above, and at this position, a container having a shape corresponding to the cavity shape of the mold 58 is formed by blowing air into the parison 54 from an air blowing device (not shown). You. Next, the mold 58 is opened by a mold clamping mechanism through a cooling process. Thereby, the container in the mold is taken out as a hollow molded product, and the next molding preparation is completed.

[0003]

However, the above-described conventional mold moving device of a hollow molding machine includes a hydraulic cylinder 60 which changes in oil temperature during molding, that is, changes in oil viscosity. Since the flow speed of the inflowing oil changes, the moving speed of the mold 58 changes accordingly, and the timing of returning the mold 58 to the air blowing position and starting the operation of the air blowing device is out of order, resulting in molding failure. There is a problem that sometimes. If the oil temperature becomes abnormally high and the viscosity of the oil becomes unnecessarily low, the flow velocity of the oil flowing into the hydraulic cylinder 60 increases, and the piston of the hydraulic cylinder 60 moves at high speed. At the stop position, the apparatus receives a large impact, and the parison 54 swings, and the position relative to the mold 58 located at the parison receiving position is not constant, so that a pinching failure is likely to occur, and a molding failure is likely to occur. . In order to prevent such a problem, it is necessary to maintain the temperature of the oil supplied to the hydraulic cylinder 60 within a predetermined temperature range. In order to stabilize the oil temperature, an oil temperature adjusting device is required, and in any case, there is another problem that the product cost increases.
An object of the present invention is to solve such a problem.

[0004]

According to the present invention, a mold is moved by using a servomotor, a rotary member for converting a rotary motion of the servomotor into a linear motion, and a meshing member engaged with the servomotor, instead of the hydraulic cylinder. The above problem is solved by controlling the moving speed of the mold to be gradually changed. That is, the present invention includes a mold (34), a mold clamping device (26) for opening and closing the mold (34), a parison cutting device (42), and an air blowing device (28). A cylindrical parison (44), which has been extruded downward through the crosshead (36) through the crosshead (36), is inserted into the mold (34) and cut to a predetermined length by the parison cutting device (42). Parison (4)
4) A mold moving device of a hollow molding machine for molding a hollow molded product by blowing air from an air blowing device (28), wherein the mold (34) reciprocates between a parison receiving position and an air blowing position. In the apparatus for driving this, the mold moving device includes a servomotor (14), a rotating member (12) driven by the servomotor (14), and a rotating motion of the rotating member (12) engaged with the servomotor (14). (18), and a lower frame (10) for supporting them, the mold clamping device (26) and the metal held by the same.
The mold (34) is placed on the mold release position side of the mold clamping device (26),
And fixed at a position protruding toward the parison receiving position,
Eccentric load is applied to the closed position and the parison receiving position.
A moving table (24), a plurality of fixing portions (32) arranged parallel to the axis of the engagement member (18) , and a plurality of guide bars (22) supported by the fixing portions (32). ,
Connection member (20) located between a plurality of fixing parts (32 )
And a sliding portion (24a) having a cylindrical hole shape is formed in the moving table (24).
The guide bar (22) is fitted into the lower frame (10), and is installed on the lower frame (10).
4) and the meshing member (18) are connected by the connecting member (20) so as to be integrally movable, and a position detector (15) capable of detecting the position of the mold (34).
And a controller (46) for inputting a signal from here on and outputting a control signal to the servomotor (14).
The controller (46) is configured such that the mold (34) is
Both stops when approaching the take-up position and air blowing position
When the mold (34) stops at the position, the mold is moved.
Reduce the speed of the mold so that the impact
You and controlling the so that. The rotating member is a ball screw (12), the engaging member is a ball nut (18), and the lower frame (1
0) can be configured to have a bearing bracket (30) that rotatably supports the end of the ball screw (12). Further, the rotating member is a pinion (72), the engaging member is a rack (74), and the lower frame (10) reduces the rotation of the servomotor (14) to the pinion (72). Transmission reducer (7
0). Further, the rotating member is a first sprocket (76), the engaging member is a roller chain (82), and the lower frame (10) reduces the rotation of the servomotor (14) to reduce the first rotation. Reducer (70) transmitting to sprocket (76)
And a second sprocket disposed at a position facing the first sprocket (76) and engaged with the roller chain (82).
It may be configured to include a sprocket (78) and a bearing bracket (80) for rotatably supporting the sprocket (78).
In addition, the rotating member is a first toothed pulley (88), the engaging member is a toothed belt (94),
The lower frame (10) is connected to the servo motor (1).
4) a speed reducer (70) for reducing the rotation and transmitting the rotation to the first toothed pulley (88); and a toothed belt (94) arranged at a position facing the first toothed pulley (88). It may have a second toothed pulley (90) to be engaged and a bearing bracket (92) rotatably supporting the second pulley (90). In addition, the code | symbol in a parenthesis shows the corresponding member of an Example.

[0005]

The mold is reciprocated between an air blowing position and a parison receiving position by being driven by a servomotor via a rotating member and a meshing member. The position of the mold is detected by a position detector, and a position signal from the position detector is input to the controller. The rotation speed of the servomotor corresponding to the position of the mold is controlled by the controller. Since the rotation speed of the servomotor is gradually reduced near the stop position, the movable portion can be stopped at a predetermined position without impact. Also,
The time required for moving the mold can be made constant. As a result, it is possible to prevent the occurrence of a defective molded product due to a defective sandwiching of the mold due to the swing movement of the parison, a defective air blowing due to an irregular molding timing, and the like.

[0006]

【Example】

(First Embodiment) FIGS. 1 and 2 show a first embodiment of the present invention. The lower frame 10 is attached to a fixed portion of the blow molding machine. Bed 10 at the lower end of lower frame 10
a, two bearing brackets 3 each having a bearing;
0 is fixed. The ball screw 12 is rotatably supported by the dual bearing bracket 30. A bracket 48 is fixed to a right end side of the bed portion 10a of the lower frame 10 in FIG. The AC servomotor 14 is attached to the bracket 48. The AC servomotor 14 is arranged so that its axis coincides with the axis of the ball screw 12. AC servo motor 14
The ball screw 12 and the ball screw 12 are interconnected by a coupling 16. A rotary encoder (position detector) 15 is attached to the AC servomotor 14. The rotary encoder 15 is an AC servo motor 14
, That is, the position of the mold 34 described later can be detected. A ball nut 18 is screwed into the ball screw 12. The connection member 2 is connected to the ball nut 18.
0 is fixed. On the upper end side of the connection member 20 in the drawing,
A moving table 24 is provided. The moving table 24 is integrally supported by the connecting member 20. In the moving table 24,
A cylindrical hole-shaped sliding portion 24a is formed. The left and right sides of the upper end of the lower frame 10 in FIG.
Three blocks 32 are fixed respectively. The guide bar 22 is fixedly supported by the two blocks 32.
The above-described movable table 24 is movably fitted to the guide bar 22 with a sliding portion 24a. Thereby, when driven by the AC servomotor 14 via the connecting member 20 and the ball nut 18, the movable table 24 can move in the axial direction while being guided by the guide bar 22. A mold clamping device 26 is attached to the moving table 24. A mold 34 is attached to the mold clamping device 26. The mold clamping device 26 is capable of moving the right half of the mold 34 in FIG. 2 to a mold opening position on the right side of the position shown in FIG. It can be moved to the mold closed position. A motion conversion mechanism is constituted by the ball screw 12, the ball nut 18, and the like. The movement conversion mechanism is driven by the AC servomotor 14 via the coupling 16 so that the rotation movement of the movement conversion mechanism can be converted into a linear movement, and the linear movement can be transmitted to the moving table 24. That is, the AC servomotor 14 causes the mold clamping device 26 and the mold 34 to reciprocate between the air blowing position indicated by the solid line in FIG. 1 and the parison receiving position indicated by the imaginary line in the drawing via the motion conversion mechanism. In addition, the movable table 24 can be driven. An upper frame 40 is fixed to an upper right end of the lower frame 10 in FIG. The air blowing device 28 is attached to the upper frame 40 in the upper part of FIG. A crosshead 36 is disposed on the left side of the air blowing device 28 in FIG. Crosshead 36
Is connected to the extrusion port of the extruder 38. A parison cutting device 42 is disposed below the crosshead 36 in FIG. The extruder 38 can supply the molten resin to the crosshead 36 from the extrusion port of the extruder 38.
Can extrude the supplied molten resin as a cylindrical parison 44 downward in the figure. The mold 34 is positioned at the parison receiving position with the mold opened, and then receives the parison 44 by closing the mold. After the parison 44 is cut to a predetermined length by the parison cutting device 42,
The air blower 28 is moved to the air blowing position, and the air blowing device 28 can blow air into the parison 44 in the mold 34 located at the air blowing position. As shown in FIG. 6, a controller 46 to which a signal of the rotary encoder 15 is input is provided. The controller 46 also receives a parison injection signal from a blow molding machine controller (not shown). The display device 17 is connected to the controller 46. The controller 46 calculates the moving speed of the mold 34 based on a signal from the rotary encoder 15 and can output the calculated moving speed to the display device 17.
A control signal can be output to the AC servomotor 14 at a timing corresponding to a parison injection signal from the blow molding machine control device.

Next, the operation of the first embodiment will be described.
The mold 34 stands by at the air blowing position with the mold opened by the mold clamping device 26. The position of this mold 34 is
The position signal is detected by the rotary encoder 15, and the position signal is input to the controller 46. The molten resin supplied from the extrusion port of the extruder 38 to the crosshead 36 is
It is extruded downward in FIG. 1 as a cylindrical parison 44. In a state where the parison 44 of a predetermined length is extruded (a state in which a parison injection signal is output from the controller for the blow molding machine (not shown) to the controller 46), the AC servomotor 14 is controlled by the control signal from the controller 46. It is driven to rotate in the forward direction. As a result, the ball screw 12 is rotated via the coupling 16, and the rotational motion is converted into a linear motion by the ball nut 18 meshing with the ball screw 12. That is, the ball nut 18 moves forward in the left direction in the figure, and the connecting member 20, the moving table 24, the mold clamping device 26, and the mold 34 integral therewith also move forward (from the air blowing position to the parison receiving position). become. The moving speed of the mold 34 can be obtained based on the rotation speed of the servomotor 14 (that is, the rotation speed of the rotary encoder 15), and the mold 34 corresponds to the magnitude of the control signal from the controller 46. Thus, for example, at a speed as shown in FIG. 7, it moves from the air blowing position to the parison receiving position along the solid arrow in the figure. That is, the moving speed of the mold 34 gradually decreases near the predetermined parison receiving position, and stops at the parison receiving position. Thus, the mold 34 can be stopped so as not to give an impact to the apparatus. The moving speed of the mold 34 is displayed on the display device 17. Next, the mold clamping device 26 is operated to close the mold, the parison 44 is held in the mold 34, and the mold is clamped. Subsequently, the parison 4 is moved by the parison cutting device 42.
4 is cut. Next, the AC servomotor 14 is driven to rotate in the backward direction. As a result, the mold 34 is moved backward along the imaginary arrow in FIG.
The moving speed of the mold 34 is gradually reduced near the air blowing position, and is stopped at the air blowing position. Also in this case, the mold 34 can be stopped so as not to give an impact to the apparatus. Next, the nozzle of the air blowing device 28 descends to blow air into the parison 44. Thereby, a resin container having a predetermined shape is molded as a hollow molded product. After the cooling step, the nozzle of the air blowing device 28 rises, the mold is opened by the mold clamping device 26, the hollow molded product falls into a product pool, and one cycle is completed.

(Second Embodiment) FIGS. 3 and 4 show a second embodiment of the present invention. The difference of the second embodiment from the first embodiment is that a rack and pinion mechanism is used instead of the ball screw mechanism which is a motion conversion mechanism.
That is, a reduction gear 70 is attached to the AC servomotor 14, and the pinion 7 is connected to the output shaft of the reduction gear 70.
2 are installed. The pinion 72 has a rack 74
Are engaged. The rack 74 is attached to the moving table 24. Other configurations are the same as those of the first embodiment.

The operation of the second embodiment is as follows. When the AC servomotor 14 is driven, its rotation is reduced by the speed reducer 70 and transmitted to the pinion 72, and the rotation is linearly moved by the rack 74 meshing with the pinion 72. This is the same as that of the first embodiment except that the moving table 24 is linearly driven by being converted into motion.

Next, FIG. 5 shows a third embodiment of the present invention. The difference of the third embodiment from the first embodiment is that a sprocket / chain mechanism is used instead of the ball screw mechanism which is a motion conversion mechanism. That is, AC
A speed reducer 70 is attached to the servomotor 14, and a first sprocket 76 is attached to an output shaft of the speed reducer 70. A second sprocket 78 is arranged at a position facing the first sprocket 76. The second sprocket 78 is rotatably supported by a bearing bracket 80. A roller chain 82 extends between the sprockets 76 and 78. A bracket 84 is attached to the moving table 24, and a roller chain fixing device 86 is attached to the bracket 84. The roller chain fixture 86 is fixed to the roller chain 82. That is, the roller chain 82 is attached to the movable base 24 via the bracket 84 and the roller chain fixing tool 86. Other configurations are the same as those of the first embodiment.

The operation of the third embodiment is as follows. When the AC servomotor 14 is driven, its rotation is reduced by the speed reducer 70 and transmitted to the sprocket 76, and the roller chain 82 This is the same as that of the first embodiment except that the moving table 24 is linearly driven by converting the rotary motion into a linear motion.

In the description of the third embodiment,
Two sprockets 76 and 78 and a roller chain 82
Instead of these, two toothed pulleys (timing pulleys) 88 and 90 (see reference numerals in parentheses in FIG. 5) and a toothed belt (a timing (Belt) 94 may be used. In this case, the second toothed pulley 9 is replaced with the bearing bracket 80 supporting the second sprocket 78.
In addition to using the bearing bracket 92 that rotatably supports the belt 0, a toothed belt fixing tool 96 is used instead of the roller chain fixing tool 86.

In the description of each of the above embodiments, the mold clamping device 26 is connected to the engaging member (the ball nut 18 in the first embodiment, the rack 74 in the second embodiment, In the third embodiment, it is mounted on the roller chain 82).
Instead of providing 4 or the like, a mold clamping device mounting portion may be formed on the engaging member, and the mold clamping device 26 may be directly attached to the engaging member. In the description of each of the above embodiments, the AC servomotor 1 is used as the servomotor.
4, but a DC servomotor can also be used.

In the above embodiments, the rotary encoder 15 is used as a position detector for detecting the position of the mold 34, and the position of the mold 34 is detected indirectly. 34 can be directly detected, and for example, a position sensor or the like can be used.

[0015]

As described above, according to the present invention,
The mold moving device is composed of a servo motor (14) and
Rotating member (12) that is rotationally driven by
And the rotational movement of the rotating member (12)
Meshing members (18) for converting into and supporting them
And a lower frame (10).
The setting (26) and the mold (34) held by this
At the mold opening / closing position side of the mold clamping device (26),
It is fixed at the position protruding to the take-up position side, and
And a carriage (2) that is subjected to an eccentric load on the parison receiving position
4) and arranged in parallel with the axis of the engagement member (18).
A plurality of fixing portions (32), and the fixing portions (32) are supported.
A plurality of guide bars (22) held and a plurality of fixing portions
(32) located between (32)
The slide (24) has a cylindrical hole-shaped sliding portion (2).
4a) is formed, and the sliding part (24a) is
The idle bar (22) is inserted into the lower frame (1).
0) installed on the mobile platform (24)
Combined with the mating member (18) with the connecting member (20)
The mold (34)
Position detector (15) capable of detecting the position of
Input signal and output control signal to servo motor (14)
And a controller (46) for performing the control.
6) The mold (34) is located at the parison receiving position and air.
-As you approach the blow position,
When the mold (34) stops, an impact is applied to the mold moving device.
In order to prevent this, the mold moving speed is controlled to be reduced.
Mold so that the impact is not always applied to the equipment.
Can be stopped, so the parison
No pinch due to parison run-out due to cutting position
Insufficient blow molding at good and air blowing positions
There is an effect that life can be prevented. Ma
In addition, the time required to move the mold can be kept constant without being affected by changes in the surrounding temperature unlike the conventional hydraulic device , preventing the occurrence of defective molded products due to irregular molding timing. It also has the effect of improving molding quality. Furthermore , since there is no need to use hydraulic equipment such as a hydraulic cylinder around the mold, there is no danger of hydraulic oil contamination due to hydraulic oil leakage, and there is an effect that a clean molding environment can be achieved .

[Brief description of the drawings]

FIG. 1 is a view showing a hollow molding machine using a mold moving device according to a first embodiment of the present invention.

FIG. 2 is a side view of FIG.

FIG. 3 is a view showing a hollow molding machine using a mold moving device according to a second embodiment of the present invention.

FIG. 4 is a side view of FIG. 3;

FIG. 5 is a view showing a hollow molding machine using a mold moving device according to a third embodiment of the present invention.

FIG. 6 is a control block diagram of the mold moving device.

FIG. 7 is a moving speed diagram of a mold.

FIG. 8 is a view showing a hollow molding machine.

FIG. 9 is a view showing a conventional mold moving device.

[Description of Signs] 10 Lower frame 12 Ball screw (rotating member) 14 AC servomotor (servo motor) 15 Rotary encoder (position detector) 18 Ball nut (meshing member) 20 Connection member 22 Guide bar 24 Moving table 24a Sliding part 26 mold clamping device 28 air blowing device 30 bearing bracket 32 block (fixed part) 34 mold 36 crosshead 38 extruder 42 parison cutting device 44 parison 46 controller 70 speed reducer 72 pinion (rotating member) 74 rack (meshing member) 76 First sprocket (rotating member) 78 Second sprocket 80, 92 Bearing bracket 82 Roller chain (meshing member) 88 First toothed pulley (rotating member) 90 Second toothed pulley 94 Toothed belt (meshing member)

Claims (5)

(57) [Claims] An extruder comprising a mold (34), a mold clamping device (26) for driving the mold to open and close, a parison cutting device (42), and an air blowing device (28). 38)
The cylindrical parison (44), which has been extruded downward through the crosshead (36), is inserted into the mold (34) and cut to a predetermined length by the parison cutting device (42). A blower that blows air from an air blowing device (28) into a parison (44) to form a hollow molded product, wherein the die (34) moves between the parison receiving position and the air blowing position. In the apparatus for driving the mold so as to reciprocate, the mold moving device includes a servomotor (14), a rotating member (12) rotationally driven by the servomotor (14), and a rotating member (12) engaged with the servomotor (14). the engagement member for converting a rotary motion into a linear motion (18), a lower frame for supporting the (10), are composed of, whereby the above-mentioned mold clamping device (26) Equity has been mold
(34) at the mold opening / closing position side of the mold clamping device (26).
Is fixed at the position where it protrudes toward the parison
Eccentric load is applied to the closed position and the parison receiving position
A movable table (24), a plurality of fixing portions (32) arranged parallel to the axis of the engagement member (18), and a plurality of guide bars (22) supported by the fixing portions (32). , Multiple
Connecting member (20) located between a number of fixing parts (32 )
And a sliding part (24a) having a cylindrical hole shape on the movable table (24).
The guide bar (22) is fitted into the sliding portion (24a), and is set on the lower frame (10). The moving table (24) and the engaging member (18) are provided. Are connected by the connecting member (20) so as to be integrally movable, and are capable of detecting the position of the mold (34).
5) and a signal to be input from the servo motor (1)
Controller for outputting a control signal to 4) and (46), has a, the controller (46), said mold (34) parison receiving
Both stops when approaching the take-up position and air blowing position
When the mold (34) stops at the position, the mold is moved.
Reduce the speed of the mold so that the impact
Mold moving device of a blow molding machine, characterized in that that control to so that. 2. The rotating member is a ball screw (12), the engaging member is a ball nut (18), and the lower frame (10) is a ball screw (12).
2. The apparatus according to claim 1, further comprising a bearing bracket rotatably supporting the end of the mold. 3. The rotation member is a pinion (72), the engagement member is a rack (74), and the lower frame (10) reduces the rotation of the servomotor (14) to reduce the pinion (72). 72) transmitted to the reduction gear (7
2. The mold moving device for a blow molding machine according to claim 1, wherein 0) is satisfied. 4. The rotating member comprises a first sprocket (7).
6), and the engaging member is a roller chain (8
2), wherein the lower frame (10) reduces the rotation of the servomotor (14) to reduce the rotation of the first sprocket (7).
And a second sprocket (78) arranged at a position facing the first sprocket (76) and engaged with the roller chain (82).
And a bearing bracket (80) for rotatably supporting the bearing
The mold moving device for a blow molding machine according to claim 1, comprising: 5. The rotating member according to claim 1, wherein the rotating member is a first toothed pulley (8).
8), wherein the engagement member is a toothed belt (94).
The lower frame (10) reduces the rotation of the servomotor (14) to reduce the rotation of the servomotor (14) to the first toothed pulley (88).
Speed reducer (70) transmitting to the first toothed pulley (8)
8) and a toothed belt (9
The mold moving device for a blow molding machine according to claim 1, further comprising: a second toothed pulley (90) meshed with 4); and a bearing bracket (92) rotatably supporting the second pulley (90).