JP7617832B2 - Ejector unit, mold clamping unit, and injection molding machine - Google Patents

Description

The present invention relates to an ejector device provided in a mold clamping device, the mold clamping device, and an injection molding machine.

Injection molding machines or press machines are provided with a clamping device that clamps the mold. There are various types of clamping devices, and for example, Patent Document 1 describes a so-called two-platen clamping device. The clamping device is equipped with an ejector device, and when an ejector rod provided in the ejector device is ejected, the molded product formed in the mold is ejected.

Japanese Patent Application Publication No. 5-269748

The ejector unit is mounted on the movable platen of the mold clamping unit, and the weight of the movable platen is essentially increased by the weight of the ejector unit. In other words, the weight of the movable platen is large. As a result, a large inertial force acts when the movable platen is slid to open and close the mold, and a driving force is required to drive the movable platen.

This disclosure provides an ejector device that reduces the weight of the movable platen, a mold clamping device equipped with a low-cost ejector device, and an injection molding machine.

Other objects and novel features will become apparent from the description of this specification and the accompanying drawings.

The mold clamping device includes a fixed platen fixed to the bed and a movable platen sliding on the bed. In the present disclosure, an ejector device is provided near the movable platen. In other words, the ejector device is provided on the bed on the side opposite to the surface of the movable platen facing the fixed platen, or on a member provided on the bed. The ejector device is provided with an ejector rod. When the movable platen is driven in a direction away from the fixed platen with the ejector rod stopped, the ejector rod slides relative to the mold provided on the movable platen, ejecting the molded product. The ejector device is provided with a position adjustment means for adjusting the position of the ejector rod relative to the bed.

The weight of the movable platen can be reduced.

1 is a front view showing an injection molding machine according to an embodiment of the present invention; FIG. 2 is a perspective view showing a mold clamping device and an ejector device according to the present embodiment. 1 is a front cross-sectional view showing a mold clamping device and an ejector device according to the present embodiment. 1 is a front cross-sectional view showing a mold clamping device and an ejector device according to the present embodiment. 1 is a front cross-sectional view showing a mold clamping device and an ejector device according to the present embodiment. 1 is a front cross-sectional view showing a mold clamping device and an ejector device according to the present embodiment. FIG. 11 is a front cross-sectional view showing an ejector device and a mold clamping device according to a second embodiment of the present invention.

Specific embodiments will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. To clarify the explanation, the following description and drawings have been simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. In addition, hatching has been omitted in some areas to avoid cluttering the drawings.

<Injection molding machine according to the present embodiment>
As shown in FIG. 1, the injection molding machine 1 according to this embodiment is composed of a mold clamping device 2 provided on a bed B, an injection device 4, and an ejector device 3 provided in association with the mold clamping device 2.

<Injection unit>
The injection device 4 is composed of a heating cylinder 6, a screw 7 contained in the heating cylinder 6, and a screw drive device 8 that drives the screw 7. The heating cylinder 6 is provided with a hopper 10, and an injection nozzle 11 is provided at the tip. The injection material is charged from the hopper 10, and when the injection material is melted by rotating the screw 7, it is metered to the tip of the screw 7. When the screw 7 is driven in the axial direction, the injection material is injected.

<Clamping device>
The mold clamping device 2 according to this embodiment is a so-called two-platen mold clamping device. That is, as shown in Fig. 2, the mold clamping device 2 includes a fixed platen 13 and a movable platen 14. The fixed platen 13 is fixed on a bed B, and the movable platen 14 is placed on linear guides 15, 15 provided on the bed B. That is, the movable platen 14 is slidable in a direction approaching and moving away from the fixed platen 13. As shown in Fig. 1, a fixed-side mold 16 is attached to the fixed platen 13, and a movable-side mold 17 is attached to the movable platen 14.

The mold clamping device 2 according to this embodiment is characterized in that the fixed platen 13 and the movable platen 14 are connected by four sets of ball screw mechanisms 18, 18, ... as shown in Figure 2. Each ball screw mechanism 18, 18, ... includes a ball screw 19, 19, ... and a ball nut 20, 20, ... into which the ball screw 19, 19, ... is screwed.

Although not shown in FIG. 2, the movable platen 14 has a through hole, and the ball nuts 20, 20, ... are fixed to the through hole. In other words, the ball screws 19, 19, ... are connected to the movable platen 14 via the ball nuts 20, 20, .... On the other hand, the ball screws 19, 19, ... penetrate the fixed platen 13 and are supported rotatably relative to the fixed platen 13. The fixed platen 13 is provided with mold opening and closing servo motors 22, 22, ... and is connected to the ball screws 19, 19, .... Therefore, when the mold opening and closing servo motors 22, 22, ... are driven, the ball screws 19, 19, ... rotate and the movable platen 14 slides. In other words, the molds 16, 17 (see FIG. 1) are opened and closed. In this way, the movable platen 14 is driven by the mold opening and closing servo motors 22, 22, ..., so that the position and speed can be controlled with high precision.

<Ejector device>
The ejector device 3 according to this embodiment is characterized in that it is provided for the bed B in this embodiment. In other words, it is not provided for the movable platen 14. Therefore, the overall weight of the movable platen 14 is reduced. The ejector device 3 is composed of rails 25, 25 provided on the bed B, a main body 27 provided on the rails 25, 25, a head 28 provided on the upper part of the main body 27, and ejector rods 30, 30 provided on the head 28.

The main body 27 can slide on the rails 25, 25 to adjust its position relative to the bed B. In other words, the main body 27 is equipped with a position adjustment means. Although not shown in FIG. 2, the main body 27 is provided with a drive mechanism equipped with a geared motor as the position adjustment means. When the geared motor is driven by a command from the controller of the injection molding machine 1 (see FIG. 1), the ejector device 3 can be moved closer to or farther away from the movable platen 14, thereby adjusting the position.

The ejector device 3 according to this embodiment is characterized in that the ejector rods 30, 30 are fixedly installed. That is, the ejector rods 30, 30 can be attached and detached to the head 28, but are fixedly attached. That is, the ejector rods 30, 30 are not driven relative to the head 28. Note that the head 28 of the ejector device 3 according to this embodiment can be replaced with one of a different shape for the main body 27. That is, the head can be replaced so that one or three or more ejector rods 30, 30, ... can be attached. In this way, in this embodiment, the number of ejector rods 30, 30, ... can be increased or decreased as necessary.

<Structure of the movable platen and movable mold>
The injection molding machine 1 (see FIG. 1) according to this embodiment is characterized by an operating method of the ejection process for ejecting a molded product. To explain the operating method, the structures of the movable platen 14 and the movable mold 17 will be briefly explained with reference to FIG. 3A. As shown in FIG. 3A, the movable platen 14 has an ejector rod hole 32 through which the ejector rod 30 passes. The movable mold 17 has a hollow chamber 34 formed therein, and an ejector plate 35 is movably provided in the hollow chamber 34. The ejector rod hole 32 communicates with the hollow chamber 34, and when the ejector rod 30 enters the ejector rod hole 32, the tip of the ejector rod 30 comes into contact with the ejector plate 35.

The movable mold 17 is formed with a recess 36 for forming a molded product. The ejector plate 35 is provided with ejector pins 38, 38, ..., and the end faces of the tips of the ejector pins 38, 38, ... form part of the recess 36. As will be explained later, when the ejector plate 35 is driven by the ejector rod 30, the ejector pins 38, 38, ... protrude from the recess 36.

<Method of operating the injection molding machine according to the present embodiment>
A method of operating the injection molding machine 1 (see FIG. 1) according to this embodiment will be described. Prior to operation, the position of the ejector device 3, i.e., the position of the ejector rod 30, is adjusted. When the position adjustment means is driven, the ejector device 3 can be slid relative to the rails 25, 25 as shown in FIG. 3A. The position adjustment is performed so that the ejector rod 30 is in an appropriate position, and the ejector device 3 is fixed to the bed B. The position adjustment is then completed.

Start operation. First, the mold clamping process is performed. As shown in FIG. 3B, the mold clamping device 2 is clamped. That is, the mold opening and closing servo motors 22, 22, ... are driven to rotate the ball screws 19, 19, .... Then, the movable platen 14 is driven via the ball nuts 20, 20, ..., and the molds 16, 17 are clamped. At this time, the ejector rod 30 moves relatively in the direction of being pulled out from the ejector rod hole 32. This is because the position of the ejector rod 30 is fixed relative to the bed B, while the movable platen 14 slides. Next, the injection process is performed. That is, the injection material is injected from the injection device 4. Then, the molded product 40 is formed in the molds 16, 17. Wait until the injection material solidifies.

The mold opening process opens the mold clamping device 2. That is, the mold opening and closing servo motors 22, 22, ... are driven to slide the movable platen 14 in a direction away from the fixed platen 13. At this time, the mold opening and closing servo motors 22, 22, ... are controlled to bring the tip of the ejector rod 30 into contact with the ejector plate 35, as shown in FIG. 3C.

The ejection process is carried out. The mold opening and closing servo motors 22, 22, ... are controlled to slide the movable platen 14 in a direction away from the fixed platen 13. When the movable platen 14 slides, the ejector rod 30 is inserted relatively to the movable platen 14, as shown in FIG. 3D. This causes the ejector plate 35 to slide, and the ejector pins 38, 38, ... are ejected from the recesses 36. The molded product 40 is ejected. Since the movable platen 14 is slid with precision by the mold opening and closing servo motors 22, 22, ..., the ejector rod 30 is driven with precision relative to the movable platen 14 and the movable mold 17. In other words, the molded product 40 is not damaged, and it can be linked to a molded product removal machine not shown in the figure.

Conventional ejector devices needed to be equipped with a servo motor to eject the ejector rod with precision. This was because it was necessary to link the device with a molded product removal machine and to eject the molded product with precision without damaging it. However, when the operating method of the injection molding machine 1 according to the present embodiment described above is implemented, there is no need to eject the ejector rod 30 of the ejector device 3 during the ejection process. Therefore, a costly servo motor is no longer necessary.

<Modification of this embodiment>
The injection molding machine 1 (see FIG. 1) according to this embodiment can be modified in various ways. For example, the object on which the ejector unit 3 is provided can be modified. In this embodiment, the ejector unit 3 has been described as being provided on the bed B. However, the ejector unit 3 may be provided on a member provided on the bed B. Furthermore, the ejector unit 3 may be provided on a completely different member. For example, the ejector unit 3 can be modified so that a bracket extending toward the movable platen 14 is attached to the fixed platen 13, and the ejector unit 3 is provided on this bracket.

In this embodiment, the ejector device 3 has been described as being equipped with a position adjustment means. In other words, it has been described as being possible to adjust the position of the ejector device 3 relative to the bed B. However, the position adjustment means is not essential, and the ejector device 3 may be fixed relative to the bed B. The object to which the ejector device 3 is attached may also be modified.

The mold clamping device 2 according to this embodiment can also be modified. The mold clamping device 2 has been described as having four sets of ball screw mechanisms 18, 18, ..., but it may have two, three, or five or more sets. The ejector device 3 according to this embodiment can also be provided for a toggle type mold clamping device. In a toggle type mold clamping device, the movable platen is opened and closed by bending and extending the toggle mechanism. This is because if the position of the movable platen can be controlled with precision, the molded product can be ejected with precision even if the ejector rod 30 of the ejector device 3 is fixed.

In the above description, the ejector device 3 according to this embodiment has a fixed ejector rod 30. However, a drive mechanism such as a servo motor may be provided so that the ejector rod 30 can be driven relative to the ejector device 3. In this case, the movable platen 14 is stopped during the ejection process, and the ejector rod 30 is pushed out.

The operating method according to this embodiment can also be modified. For example, the mold opening process and the ejection process of the operating method according to this embodiment described above can be modified. In the mold opening process, the movable platen 14 is stopped so that the tip of the ejector rod 30 contacts the ejector plate 35 in preparation for the next ejection process. Then, the ejection process is carried out. However, the mold opening process and the ejection process may be carried out continuously. In other words, the movable platen 14 may be driven continuously without being temporarily stopped.

The ejector device 3 according to this embodiment can be modified to eject the ejector rod 30 in the same manner as in a conventional ejector device. Such a second embodiment is shown in FIG. 4. In the ejector device 3A according to this second embodiment, a stopper 42 is provided on the rail 25. In the ejector device 3A, when the geared motor constituting the position adjustment means is driven, the ejector device 3A and the ejector rod 30 slide toward the movable platen 14. However, the amount of sliding is determined by the stopper 42. If the position of the stopper 42 is appropriately adjusted, the ejector rod 30 can be pushed with precision by driving the geared motor, and the molded product can be ejected.

The invention made by the inventor has been specifically described above based on the embodiments, but the present invention is not limited to the embodiments already described, and it goes without saying that various modifications are possible without departing from the gist of the invention. The multiple examples described above can also be implemented in appropriate combinations.

REFERENCE SIGNS LIST 1 injection molding machine 2 mold clamping device 3 ejector device 4 injection device 6 heating cylinder 7 screw 8 screw drive device 11 injection nozzle 13 fixed platen 14 movable platen 15 linear guide 16 fixed mold 17 movable mold 18 ball screw mechanism 19 ball screw 20 ball nut 22 mold opening/closing servo motor 25 rail 27 main body 28 head 30 ejector rod 32 ejector rod hole 34 hollow chamber 35 ejector plate 36 recess 38 ejector pin 40 molded product B bed

Claims (11)

An ejector device provided in a mold clamping device,
The mold clamping device includes a fixed platen fixed to a bed,
A movable platen that slides on the bed,
the ejector device is provided on the bed or on a member provided on the bed, on a side of the movable platen opposite to a surface facing the fixed platen,
the ejector device includes an ejector rod, and when the movable platen is driven in a direction away from the fixed platen with the ejector rod stopped, the ejector rod slides relative to a mold provided on the movable platen to eject a molded product,
The ejector device includes a position adjustment means for adjusting a relative position of the ejector rod with respect to the bed . The mold clamping device includes a plurality of ball screw mechanisms that connect the fixed platen and the movable platen;
a mold opening/closing servo motor that drives the ball screw mechanism,
2. The ejector device according to claim 1 , wherein the movable platen is driven by driving the mold opening/closing servomotor. The ejector device according to claim 1 or 2, wherein the position adjustment means includes a geared motor. A fixed plate fixed to the bed;
A movable platen that slides on the bed;
An ejector device,
the ejector device is provided on the bed or on a member provided on the bed, on a side of the movable platen opposite to a surface facing the fixed platen,
the ejector device includes an ejector rod, and when the movable platen is driven in a direction away from the fixed platen with the ejector rod stopped, the ejector rod slides relative to a mold provided on the movable platen to eject a molded product,
The ejector device includes a position adjustment means for adjusting a relative position of the ejector rod with respect to the bed . The mold clamping device includes a plurality of ball screw mechanisms that connect the fixed platen and the movable platen;
a mold opening/closing servo motor that drives the ball screw mechanism,
5. The mold clamping device according to claim 4 , wherein the movable platen is driven by driving the mold opening and closing servomotor. The mold clamping device according to claim 5 , wherein the ball screw mechanism comprises four sets. The mold clamping device according to any one of claims 4 to 6 , wherein the position adjustment means includes a geared motor. an injection device for injecting an injection material;
A mold clamping device that clamps a mold,
The mold clamping device includes a fixed platen fixed to a bed,
A movable platen that slides on the bed;
An ejector device,
the ejector device is provided on the bed or on a member provided on the bed, on a side of the movable platen opposite to a surface facing the fixed platen,
the ejector device includes an ejector rod, and when the movable platen is driven in a direction away from the fixed platen with the ejector rod stopped, the ejector rod slides relative to a mold provided on the movable platen to eject a molded product,
The ejector device includes a position adjustment means for adjusting a relative position of the ejector rod with respect to the bed . The mold clamping device includes a plurality of ball screw mechanisms that connect the fixed platen and the movable platen;
a mold opening/closing servo motor that drives the ball screw mechanism,
9. The injection molding machine according to claim 8 , wherein the movable platen is driven by driving the mold opening and closing servomotor. 10. The injection molding machine according to claim 9 , wherein the ball screw mechanism comprises four sets. The injection molding machine according to any one of claims 8 to 10 , wherein the position adjustment means comprises a geared motor.

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