WO2014092043A1

WO2014092043A1 - Injection-molding machine

Info

Publication number: WO2014092043A1
Application number: PCT/JP2013/082946
Authority: WO
Inventors: 井上　誠
Original assignee: 東洋機械金属株式会社
Priority date: 2012-12-13
Filing date: 2013-12-09
Publication date: 2014-06-19
Also published as: JP2014117817A; CN104837600A; JP6055669B2; CN104837600B

Abstract

This invention is provided with: a ball screw mechanism (17) comprising a ball screw shaft (15) and a nut body (16); a heating cylinder mounting bracket (13) moved so as to advance or retract with the nut body (16); an injection nozzle (11) mounted on the heating cylinder mounting bracket (13) with a heating cylinder (10) interposed therebetween; a nozzle touch motor (22) for causing the ball screw shaft (15) to rotate; and a unit base (20) for supporting the heating cylinder mounting bracket (13) so as to advance or retract freely. The rear end of the ball screw shaft (15) is retractably supported so that it is possible to moderate the reaction force generated when the injection nozzle (11) is brought into intimate contact with the resin inlet (6a) of the fixed mold (6) by the ball screw shaft (15) being caused to rotate and the nut body (16) being caused to advance.

Description

Injection molding machine

The present invention relates to an injection molding machine that injects a thermoplastic resin melted by a heating cylinder into a mold cavity closed from an injection nozzle. In particular, the present invention relates to an injection molding machine provided with a nozzle touch mechanism for bringing an injection nozzle into close contact with or separating from an injection port.

In a conventional injection molding machine that has been used conventionally, molten resin is supplied from an injection nozzle to a mold cavity. Therefore, a resin injection port to which the tip of the injection nozzle is in close contact is formed in the mold attached to the fixed die plate. When the injection nozzle is brought into close contact with or separated from the resin injection port, the injection nozzle is advanced and retracted by the nozzle touch mechanism. While the injection molding machine is in operation and manufacturing a molded body, the tip of the injection nozzle is pressed against the resin injection port.

In an electric injection molding machine equipped with a nozzle touch mechanism, a ball screw mechanism or the like that converts a rotational movement composed of a ball screw shaft and a nut body into a linear movement is used as the nozzle touch mechanism. When the ball screw shaft is rotated by driving the motor, the nut body is moved forward or backward accordingly. Then, by moving the injection unit in accordance with the forward / backward movement of the nut body, the injection nozzle provided in the injection unit is brought into close contact with or separated from the resin injection port as described above. As such technology, there is Patent Document 1 (Japanese Patent Laid-Open No. 9-277306) filed by the applicant of the present application. In Patent Document 1, a pair of mechanisms for converting the rotational motion of an electric motor into linear motion is disposed in an injection unit, and a tip is attached to a tip of a pair of ball screw shafts configured in the mechanism. An injection molding machine connected to a fixed die plate is disclosed.

7A and 7B are explanatory views showing a schematic configuration of an electric injection molding machine provided with a conventional nozzle touch mechanism. An electric injection molding machine 100 as shown in FIGS. 7A and 7B includes a heating cylinder 102 with an injection nozzle 101 attached to the tip, a heating cylinder mounting bracket 103 that holds the rear end side of the heating cylinder 102, and the inside of the heating cylinder 102. And a nozzle touch mechanism 107 for bringing the tip of the injection nozzle 101 into close contact with or separating from a resin injection port 106 of a fixed mold 104 mounted on a fixed die plate 105 and a screw (not shown) that can be moved forward and backward. Prepare. In FIG. 7A, the tip of the ball screw shaft 110 of the ball screw mechanism configured in the nozzle touch mechanism 107 and the fixed die plate 105 are connected via a spring 111. 7B, the nozzle touch mechanism 107 includes a spring 111, and the tip of the ball screw shaft 110 of the ball screw mechanism configured in the nozzle touch mechanism 107 and the fixed die plate 105 are connected via a rod 112. . Then, when the nozzle touch motor 113 is driven, the nut body 114 screwed to the ball screw shaft 110 is advanced toward the resin injection port 106, so that the injection nozzle 101 is advanced together with the heating cylinder mounting bracket 103. And is in close contact with the resin injection port 106.

Japanese Patent Laid-Open No. 9-277306

By the way, the conventional injection molding machine shown in Patent Document 1 and FIGS. 7A and 7B has a fixed die plate 105 and a nozzle touch mechanism on the injection unit side when performing maintenance of the injection nozzle, such as cleaning the tip of the injection nozzle. Since members such as the spring 110 and the rod 112 configured in 107 are integrally connected, there may be a problem that such members interfere with each other. That is, in general, the injection molding machine, from the viewpoint of easily cleaning the tip of the injection nozzle, with the rear side of the injection unit as a fulcrum, so that the tip of the injection nozzle does not face the fixed die plate side, The injection nozzle provided in the heating cylinder has a structure that rotates in the horizontal direction. However, when the fixed die plate and the member configured in the nozzle touch mechanism are integrally connected, when the injection nozzle provided in the heating cylinder is swung, a bolt, a nut, or the like connecting them is used. The attachment means consisting of must be removed one by one, and there is a problem that a complicated work has to be done. Therefore, as in Patent Document 1, when there are a plurality of screw shafts connected to the fixed die plate, there is a situation in which workability is inferior because time is taken for removing and assembling the screw shafts.

Further, the injection molding machine in which the ball screw mechanism including the ball screw shaft 110 and the like shown in FIGS. 7A and 7B is arranged below the injection nozzle 101 is arranged such that the injection nozzle 101 is inserted into the resin injection port 106 of the fixed mold 104. When touched, a tensile force (reaction force) F1 by the ball screw shaft 110 and a pressing force F2 by the injection nozzle 101 act on the fixed die plate 105 to which the fixed mold 104 is attached. Therefore, when the mold is opened, a moment indicated by an arrow M acts on the fixed die plate 105, and the fixed die plate 105 tilts so that the upper side bows around the lower end side as a fulcrum. Therefore, when mold closing (clamping) is performed in such a state, the parallelism of the PL surface between the movable mold 116 fixed to the movable die plate 115 and the fixed mold 104 fixed to the fixed die plate 105. Therefore, the mold is damaged, the resin of the molded product to be molded is biased, and a high-quality molded product cannot be obtained.

Moreover, in order to keep the parallelism between the movable mold 116 and the fixed mold 104 good when the mold is closed (clamping), it is not unreasonable to reduce the nozzle touch force. If this is weak, there will be a problem that resin leakage occurs from the tip of the injection nozzle 101.

The present invention has been made in view of the above problems, and prevents the fixed die plate to which the mold is attached from being tilted by the nozzle touch force so that the parallelism of the mold can be maintained satisfactorily. It aims at providing the injection molding machine which made it possible to obtain a high-quality molded object.

The invention of this injection molding machine is provided integrally with a ball screw mechanism comprising a ball screw shaft that is rotatably provided and a nut body that is screwed to the ball screw shaft and advances and retracts as the ball screw shaft rotates. A heating cylinder mounting bracket that is advanced and retracted together with the nut body, a heating cylinder that is attached to the heating cylinder mounting bracket and has a screw therein, an injection nozzle provided at a tip of the heating cylinder, and the ball screw shaft. A nozzle touch motor, wherein a unit base for supporting the heating cylinder mounting bracket is provided at a lower portion of the heating cylinder mounting bracket so that the heating cylinder mounting bracket can be moved forward and backward. And a ball screw mechanism composed of a single nut body and the nozzle tap. An injection nozzle provided at the tip of the heating cylinder together with the heating cylinder mounting bracket by rotating the ball screw shaft by driving the nozzle touch motor and advancing the nut body. The rear end of the ball screw shaft is supported so as to be retractable so that the reaction force against the ball screw shaft generated at that time can be alleviated when it is brought into close contact with the resin inlet of the mold attached to the mold.

The invention of the present injection molding machine allows the injection nozzle to be in close contact with the resin injection port with a weak force when the mold is opened, while the weak force is applied when the mold is clamped. And a control means for controlling the driving of the nozzle touch motor so that the injection nozzle is brought into close contact with the resin injection port with a strong force.

The invention of the present injection molding machine is characterized in that the heating cylinder mounting bracket is engaged with a guide rail provided at an upper portion of the unit base and supported so as to be freely advanced and retracted.

The invention of the present injection molding machine is characterized in that a turning shaft for turning the unit base in the horizontal direction is provided on the rear side of the unit base.

According to the present invention, when the injection molding machine is in operation, the injection nozzle advances with respect to the resin injection port formed in the mold by the advance operation of the injection nozzle accompanying the advance of the nut body by the rotation of the ball screw shaft. Close contact. For this reason, the fixed die plate on which the mold is mounted tends to tilt due to the pressing force of the injection nozzle. However, the reaction force generated at that time against the ball screw shaft can be attenuated by the rear end of the ball screw shaft being retracted. Therefore, it is possible to suppress the fixed die plate from being tilted by the pressing force of the injection nozzle during mold clamping or mold opening. Thereby, it becomes possible to keep the parallelism of a metal mold | die favorable, and a high quality molded object can be obtained.

Furthermore, since the injection nozzle is in close contact with the resin injection port during mold opening with a weaker force than during mold clamping, it is possible to further suppress tilting of the fixed die plate during mold opening. The parallelism of the mold can be kept better.

Furthermore, the unit base that accommodates the ball screw mechanism composed of the ball screw shaft and the nut body can be rotated in the horizontal direction around the rotation shaft, and can be arranged at a position where maintenance is easy to perform. Thereby, in addition to the maintenance of the ball screw mechanism, the maintenance of the injection nozzle and the heating cylinder rotated together with the unit base can be easily performed. In addition, a ball screw mechanism configured as a nozzle touch mechanism for the injection nozzle is housed in the unit base. Thus, like a conventional injection molding machine, a structure in which a ball screw shaft configured as a nozzle touch mechanism and a spring or a rod integrally connected to the ball screw shaft are connected to a fixed die plate. No need to adopt. Therefore, the injection nozzle, the heating cylinder, and the ball screw mechanism can be easily turned without performing a complicated operation of detaching them from the fixed die plate. Therefore, maintenance of the injection nozzle, the heating cylinder, and the ball screw mechanism can be easily performed.

FIG. 1 is a schematic configuration diagram illustrating an injection molding machine according to an example of the present invention. FIG. 2 is a cross-sectional view showing an injection unit configured in the injection molding machine. FIG. 3 is a plan view showing an injection unit configured in the injection molding machine. FIG. 4 is a cross-sectional view showing a unit base configured in the injection unit. FIG. 5 is a plan view showing a unit base configured in the injection unit. FIG. 6 shows the waveform of the nozzle touch force when the injection molding machine is operated and the injection nozzle is brought into contact with the resin injection port with a solid line, and the waveform of the mold opening / closing speed of the movable mold with a dotted line. It is a graph, the vertical axis represents the torque value of the nozzle touch force, and the horizontal axis represents the passage of time. FIG. 7A is a schematic configuration diagram showing a conventional injection molding machine, in which a ball screw shaft tip of a ball screw mechanism configured in a nozzle touch mechanism and a fixed die plate are connected via a spring. FIG. 7B is a schematic configuration diagram showing a conventional injection molding machine, in which a ball screw shaft tip of a ball screw mechanism configured in a nozzle touch mechanism and a fixed die plate are connected via a rod.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. Of course, it goes without saying that the present invention can be easily applied to configurations other than those described in the embodiments without departing from the spirit of the invention.

An electric injection molding machine 1 according to an example of the present invention shown in FIG. 1 manufactures a molded body using pellets as a granular thermoplastic resin as a raw material. The injection molding machine 1 includes a machine base 2, and an injection unit 3 and a mold clamping unit 4 are disposed on the machine base 2.

In the mold clamping unit 4, a mold opening / closing is performed for mold clamping (mold closing) and mold opening by moving the movable mold 8 mounted on the movable die plate 7 forward and backward with respect to the fixed mold 6 mounted on the fixed die plate 5. Provide mechanism. In the mold opening / closing mechanism in the present embodiment, the movable mold 8 is repeatedly opened and closed with respect to the fixed mold 6 by bending the toggle link mechanism 9 using the driving force of the motor as a drive source. The fixed mold 6 is formed with a resin inlet 6a for supplying molten resin to the mold cavity. An injection nozzle 11 described later is in close contact with the resin injection port 6a.

The injection unit 3 includes a cylindrical heating cylinder 10, an injection nozzle 11 provided at the tip of the heating cylinder 10, and a screw provided in the heating cylinder 10 for kneading the thermoplastic resin supplied into the heating cylinder 10. 12, a heating cylinder mounting bracket 13 for holding the heating cylinder 10 in a cantilever manner, a moving body 18 that rotatably supports the screw 12 and moves forward and backward with respect to the heating cylinder mounting bracket 13, and pellets made of thermoplastic resin. A hopper 14 to be thrown in, a ball screw shaft 15 that is rotatably supported, and a ball screw mechanism 17 that is screwed into the ball screw shaft 15 and advances and retracts as the ball screw shaft 15 rotates. It is disposed below the mounting bracket 13 and the moving body 18 and accommodates the ball screw mechanism 17. The unit base 20, the nozzle touch motor 22 that rotationally drives the ball screw shaft 15 via a drive transmission means 21 such as a belt, and the screw 12 is rotated when the thermoplastic resin heated and melted in the heating cylinder 10 is measured. A metering motor 23, an injection motor 24 that advances the screw 12 together with the moving body 18 when the measured resin is injected into the mold cavity, a control unit 25 that controls various controls of the entire injection molding machine, and the like are configured. Yes. A heating cylinder mounting bracket 13 is integrally provided on the nut body 16 of the ball screw mechanism 17. The nozzle touch motor 22 is provided integrally with the unit base 20. The weighing motor 23 and the injection motor 24 are integrally provided on the moving body 18.

Further, a guide rail 26 parallel to the ball screw shaft 15 is provided on the upper portion of the unit base 20. A slider 27 formed below the heating cylinder mounting bracket 13 and the moving body 18 is engaged with the guide rail 26. A swivel shaft 28 that protrudes downward is provided at the lower part of the rear side of the unit base 20. A turning shaft 28 is fitted into a hole 29 provided in the machine base 2 via a bearing (not shown), and the unit base 20 is configured to be turnable in the horizontal direction.

The ball screw shaft 15 accommodated in the unit base 20 is rotatably supported by two

bearings

30 and 31 disposed on the front and rear sides thereof. In the front bearing 30, the tip end side of the ball screw shaft 15 is supported so as not to move forward and backward. On the other hand, in the rear bearing 31, the rear end of the ball screw shaft 15 is supported so as to be retractable. Thereby, when the ball screw shaft 15 is extended at the time of mold clamping or the like, the reaction force against the ball screw shaft 15 is absorbed by the rear end of the ball screw shaft 15 being retracted. More specifically, for example, the impact associated with the extension of the ball screw shaft 15 during mold clamping is attenuated.

Further, the control means 25 controls the drive of the nozzle touch motor 22 so that, as shown in FIG. 6, when the mold in which the movable mold 8 is separated from the fixed mold 6 is being opened, the injection nozzle 11 is closely attached to the resin inlet 6a with a weak force of 2.4 kN. On the other hand, when the mold is being clamped, the injection nozzle 11 is brought into close contact with the resin injection port 6a with a force of 37.0 kN which is stronger than the weak force of 2.4 kN. As is apparent from the graph of FIG. 6, in the initial stage of mold opening, the waveform of the nozzle touch force is slightly disturbed, but repeatedly performed during mold clamping and during mold opening. No significant disturbance has occurred in the waveform of the nozzle touch force, and it can be seen from the graph in FIG. 6 that the problem that the fixed die plate 5 is tilted is suppressed.

According to the injection molding machine 1 as described above, during the operation of the injection molding machine 1, the heating cylinder mounting bracket 13 and the heating cylinder 10 are associated with the advancement of the nut body 16 due to the rotation of the ball screw shaft 15. By the forward movement of the injection nozzle 11, the tip side of the injection nozzle 11 is brought into close contact with the resin injection port 6 a formed in the fixed mold 6. 5 tries to tilt. However, the reaction force generated at that time on the ball screw shaft 15 can be attenuated by the rear end of the ball screw shaft 15 being retracted. Therefore, unlike a conventional injection molding machine, a spring provided for the purpose of attenuating such an impact is unnecessary, and the cost can be reduced. Furthermore, it is possible to prevent the fixed die plate 5 from being tilted due to the pressing force of the injection nozzle 11 during mold clamping or mold opening, so that the parallelism of the mold can be kept good. As a result, a high-quality molded product can be obtained.

Furthermore, since the injection nozzle 11 is in close contact with the resin injection port 6a during mold opening with a weaker force than during mold clamping, the tilting of the fixed die plate 5 during mold opening is further suppressed. The parallelism of the mold can be kept better. In addition, “It is possible to further suppress the tilting of the fixed die plate 5 during mold opening”, but it is fixed during the mold opening, particularly during the mold opening. It is possible to further suppress the die plate 5 from being inclined.

Furthermore, the unit base 20 containing the ball screw mechanism 17 composed of the ball screw shaft 15 and the nut body 16 can be rotated in the horizontal direction around the rotation shaft 28 and disposed at a position where maintenance can be easily performed. Thereby, in addition to the maintenance of the ball screw shaft 15 and the nut 16 of the ball screw mechanism 17, maintenance of the injection nozzle 11, the heating cylinder 10, and the

various motors

22, 23, 24, etc. that are swung together with the unit base 20 and replacement of parts due to failure, etc. Can be easily performed. In addition, a ball screw mechanism 17 configured as a nozzle touch mechanism of the injection nozzle 11 is accommodated in the unit base 20. Thus, like a conventional injection molding machine, a structure in which a ball screw shaft configured as a nozzle touch mechanism and a spring or a rod integrally connected to the ball screw shaft are connected to a fixed die plate. Since it is not employed, the injection nozzle 11, the heating cylinder 10, the ball screw mechanism 17, and the like can be easily turned without performing a complicated operation of detaching them from the fixed die plate 5. Therefore, maintenance of the injection nozzle 11, the heating cylinder 10, the ball screw mechanism 17 and the like can be easily performed.

Furthermore, unlike a conventional injection molding machine, since there is not a plurality of ball screw shafts that are operated at the time of nozzle touch, but only one ball screw shaft is configured, the number of parts can be reduced, thereby reducing costs. it can.

As described above in detail, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist of the present invention. For example, in the above-described embodiment, the example in which the pivot shaft 28 is provided on the rear side of the unit base 20 and the hole 29 in which the pivot shaft 28 is fitted is provided in the machine base 2 is shown. May be provided with a pivot shaft 28 and a hole 29 into which the pivot shaft 28 is fitted may be formed on the lower surface of the unit base 20.

DESCRIPTION OF SYMBOLS 1 Injection molding machine 5 Fixed die plate 6 Fixed mold 6a Resin injection port 10 Heating cylinder 11 Injection nozzle 12 Screw 13 Heating cylinder mounting bracket 15 Ball screw shaft 16 Nut body 17 Ball screw mechanism 20 Unit base 22 Nozzle touch motor 25 Control means 26 Guide rail 28 Rotating axis

Claims

A ball screw mechanism comprising a ball screw shaft that is rotatably provided and a nut body that is screwed to the ball screw shaft and is advanced and retracted with the rotation of the ball screw shaft;
A heating cylinder mounting bracket provided integrally with the nut body and advanced and retracted together with the nut body, a heating cylinder mounted on the heating cylinder mounting bracket and provided with a screw inside, and an injection nozzle provided at the tip of the heating cylinder And an injection molding machine comprising a nozzle touch motor that rotates the ball screw shaft,
A unit base is provided below the heating cylinder mounting bracket to support the heating cylinder mounting bracket so as to freely advance and retract.
The unit base accommodates a ball screw mechanism composed of the single ball screw shaft and the single nut body, and is provided with the nozzle touch motor,
By rotating the ball screw shaft by driving the nozzle touch motor and moving the nut body forward, the injection nozzle provided at the tip of the heating cylinder together with the heating cylinder mounting bracket is mounted on a fixed die plate. An injection molding machine, wherein the rear end of the ball screw shaft is supported so as to be retractable so that a reaction force against the ball screw shaft generated at the time when the resin injection port is brought into close contact with the mold can be relaxed.
When the mold is opened, the injection nozzle is brought into close contact with the resin injection port with a weak force, while when the mold is clamped, the injection nozzle is moved with a force stronger than the weak force. The injection molding machine according to claim 1, further comprising a control unit that performs drive control of the nozzle touch motor so as to be in close contact with the resin injection port.
The injection molding machine according to claim 1 or 2, wherein the heating cylinder mounting bracket is engaged with a guide rail provided at an upper part of the unit base and supported so as to be movable forward and backward.
4. The injection molding machine according to claim 3, wherein a revolving shaft for revolving the unit base in a horizontal direction is provided on the rear side of the unit base.