EP4596140A1

EP4596140A1 - Screw maintenance jig of metal injection molding machine, and screw maintenance method

Info

Publication number: EP4596140A1
Application number: EP23871949.6A
Authority: EP
Inventors: Michio Butani
Original assignee: Japan Steel Works Ltd
Current assignee: Japan Steel Works Ltd
Priority date: 2022-09-30
Filing date: 2023-09-13
Publication date: 2025-08-06
Also published as: CN119855666A; EP4596140A4; WO2024070716A1; TW202421304A; JP2024051419A

Abstract

A screw maintenance jig (30) comprises a pipe-like screw accommodation part (43) and a suspension part (40). The screw accommodation part (43) comprises pipe-divisional members (34, 38) that each have a shape resulting the screw accommodation part (43) being divided either by a plane that is parallel to a cylindrical axis thereof or by a plane that contains the cylindrical axis in the surface thereof. The screw accommodation part (43) is formed by having the pipe-divisional members (34, 38) either arranged in proximity to each other or joined together. The interior of the screw accommodation part (43) is opened up by having the pipe-divisional members (34, 38) either arranged away from each other or separated from each other.

Description

TECHNICAL FIELD

The present invention relates to a screw maintenance jig and a screw maintenance method for maintaining a screw of a metal injection molding machine that is configured to melt and inject metals as an injection material.

BACKGROUND ART

A so-called metal injection molding machine that uses a metal such as a magnesium alloy as an injection material includes, for example, a mold clamping device provided on a bed and an injection device provided on the bed as described in Patent Literature 1. The injection device includes a heating cylinder and a screw housed in the heating cylinder so as to be drivable in a rotation direction and an axial direction. When the metal injection material is supplied from a hopper to the heating cylinder and the screw is rotated while the heating cylinder is heated by a heater, the metal injection material is melted and delivered downstream by the screw, and a predetermined amount of molten metal is measured in a downstream portion of the heating cylinder. When the molten metal is injected into a mold clamped by the mold clamping device, a molded article made of metal is obtained.

CITATION LIST

PATENT LITERATURE

Patent Literature 1: JPH08-033967A

SUMMARY OF INVENTION

TECHNICAL PROBLEM

In general, a metal injection molding machine heats the heating cylinder to a relatively high temperature (for example, 500°C) in order to melt a metal of an injection material. The screw driven within such a high-temperature heating cylinder is usually periodically taken out from the heating cylinder and subjected to maintenance such as cleaning. Here, the magnesium alloy, which is widely used as the injection material, has the property of burning violently when exposed to the atmosphere in a high temperature state. When the magnesium alloy is used as the injection material, since the magnesium alloy adheres to the screw taken out from the heating cylinder, it is preferable to cool the screw without exposing the screw to the atmosphere as much as possible. On the other hand, it is preferable that the screw is exposed for cleaning or the like after cooling. Therefore, when performing maintenance such as cleaning, there is a demand for an appropriate jig that prevents exposure of the screw when the screw is taken out from the heating cylinder for cooling, and that exposes the screw after the screw is cooled.
The present disclosure provides a screw maintenance jig for a metal injection molding machine that can prevent contact between a screw and the atmosphere as much as possible when the screw is taken out for cooling, and can easily expose the screw after cooling.
Other problems and novel features will become apparent from description of the present description and the accompanying drawings.

SOLUTION TO PROBLEM

According to the present disclosure, a screw maintenance jig that is for maintaining a screw of a metal injection molding machine includes: a pipe-shaped screw accommodation portion configured to accommodate the screw inserted therein; and a plurality of suspension portions provided for the screw accommodation portion. The screw accommodation portion includes a plurality of pipe division members each having a shape obtained by dividing the screw accommodation portion by a plane that is parallel to a cylindrical axis of the screw accommodation portion or a plane that includes the cylindrical axis within the plane. The screw accommodation portion is configured such that when the plurality of pipe division members are arranged close to each other or joined together, the pipe-shaped screw accommodation portion is formed, and when at least some of the pipe division members are arranged apart from each other or separated, an inside of the screw accommodation portion is opened.

ADVANTAGEOUS EFFECTS OF INVENTION

The screw maintenance jig according to the present disclosure can prevent contact between the screw and the atmosphere when the screw is taken out for cooling, and can easily expose the screw after cooling.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] FIG. 1 is a front view showing a metal injection molding machine according to the present embodiment.
[FIG. 2A] FIG. 2A is a perspective view of a screw maintenance jig according to a first embodiment.
[FIG. 2B] FIG. 2B is a perspective view of the screw maintenance jig according to the first embodiment.
[FIG. 3] FIG. 3 is a flowchart illustrating a screw maintenance method according to the first embodiment.
[FIG. 4A] FIG. 4A is a top view showing a part of the metal injection molding machine according to the present embodiment.
[FIG. 4B] FIG. 4B is a front view of the screw maintenance jig according to the first embodiment.
[FIG. 4C] FIG. 4C is a top view of the part of the metal injection molding machine according to the present embodiment and the screw maintenance jig according to the first embodiment.
[FIG. 4D] FIG. 4D is a top view of the part of the metal injection molding machine according to the present embodiment and the screw maintenance jig according to the first embodiment.
[FIG. 4E] FIG. 4E is a front view of the screw maintenance jig according to the first embodiment with a screw inserted.
[FIG. 4F] FIG. 4F is a front view of the screw maintenance jig according to the first embodiment with the screw inserted.
[FIG. 4G] FIG. 4G is a front view of the screw and the screw maintenance jig according to the first embodiment.
[FIG. 5A] FIG. 5A is a front view of a screw maintenance jig according to a comparative example with the screw inserted.
[FIG. 5B] FIG. 5B is a front view of the screw and the screw maintenance jig according to the comparative example.
[FIG. 6A] FIG. 6A is a perspective view of a screw maintenance jig according to a second embodiment.
[FIG. 6B] FIG. 6B is a perspective view of a screw maintenance jig according to a third embodiment.
[FIG. 7A] FIG. 7A is a side cross-sectional view of the screw and a screw maintenance jig according to a fourth embodiment.
[FIG. 7B] FIG. 7B is a side cross-sectional view of the screw and the screw maintenance jig according to the fourth embodiment.
[FIG. 8] FIG. 8 is a front view of a screw maintenance jig according to a modification of the first embodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, specific embodiments will be described in detail with reference to the drawings. The present disclosure is not limited to the following embodiments. In order to clarify the description, the following description and the drawings are simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals, and repeated description thereof is omitted as necessary. In addition, hatching may be omitted to avoid complicating the drawings.

A metal injection molding machine 1 according to the present embodiment, which is a subject of a screw maintenance method to be described later, will be described. As illustrated in FIG. 1, the metal injection molding machine 1 according to the present embodiment includes a mold clamping device 2 provided on a bed B, and an injection device 3 slidably provided on the bed B.

The mold clamping device 2 includes a fixed platen 5 fixed to the bed B, a movable platen 6 slidably provided on the bed B, and a mold clamping housing 7 also slidably provided on the bed B. The fixed platen 5 and the mold clamping housing 7 are coupled by tie bars 9, 9, ..., and the movable platen 6 is penetrated by the tie bars 9, 9, ... A mold clamping mechanism (that is, a toggle mechanism 10 in the present embodiment) is provided between the movable platen 6 and the mold clamping housing 7. The fixed platen 5 is provided with a fixed mold 12, and the movable platen 6 is provided with a movable mold 13. In the mold clamping device 2, when the toggle mechanism 10 is driven, the fixed mold 12 and the movable mold 13 are opened and closed.

The injection device 3 is configured to melt and inject a metal material. The injection device 3 is configured as follows. That is, the injection device 3 includes a heating cylinder 15, a screw 16 housed in the heating cylinder 15 so as to be drivable in a rotation direction and an axial direction, and a screw driving device 17 configured to drive the screw 16. A base 18 is slidably provided on the bed B, and the screw driving device 17 is provided on the base 18. Therefore, the injection device 3 as a whole is configured to approach or separate from the mold clamping device 2. The screw driving device 17 is connected to the base 18 via a rotation shaft 19. Therefore, the injection device 3 is horizontally rotatable around the rotation shaft 19. The heating cylinder 15 includes a hopper 21 and an injection nozzle 22.

[First Embodiment]

FIG. 2A shows a screw maintenance jig 30 according to the first embodiment. The screw maintenance jig 30 according to the first embodiment includes a lower member 31 and an upper member 32. The lower member 31 includes a lower pipe division member 34 and lower coupling brackets 35 and 35 attached to the lower pipe division member 34. The lower pipe division member 34 is a pipe division member having a shape (so-called halved shape) obtained by dividing a metal cylindrical pipe by a plane parallel to a cylindrical axis thereof (specifically, a plane having the cylindrical axis on the plane). Bolt holes 36 and 36 are formed in each of the lower coupling brackets 35 and 35.
Similarly to the above, the upper member 32 also includes an upper pipe division member 38, which is a pipe division member having a shape (so-called halved shape) obtained by dividing the metal cylindrical pipe by the plane parallel to the cylindrical axis thereof. The upper member 32 includes the upper pipe division member 38, upper coupling brackets 39 and 39 attached to the upper pipe division member 38, and eyebolts (that is, suspension portions 40 and 40) provided on the upper coupling brackets 39 and 39. The upper coupling brackets 39 and 39 are each provided with bolts 42 and 42.
The lower member 31 and the upper member 32 are joined together as illustrated in FIG. 2B. That is, the upper coupling brackets 39 and 39 are joined to the lower coupling brackets 35 and 35, and both are fastened together by the bolts 42, 42, ... Then, the lower pipe division member 34 and the upper pipe division member 38 form a screw accommodation portion 43 having the shape of a single metal cylindrical pipe. As will be described later, the screw 16 (see FIG. 1) is inserted and accommodated in the screw accommodation portion 43. Therefore, an inner diameter of the screw accommodation portion 43 is slightly larger than a diameter of the screw 16 so that the screw 16 can be inserted.

A screw maintenance method performed using the screw maintenance jig 30 according to the first embodiment will be described with reference to a flowchart shown in FIG. 3. First, an injection device rotating step S01 is performed. That is, as shown in FIG. 4A, the injection device 3 is rotated to separate a tip end (that is, downstream side) of the heating cylinder 15 from the mold clamping device 2. Before the rotation, the injection device 3 is moved backward in a direction away from the mold clamping device 2 as necessary. After the rotation, the injection nozzle 22 (see FIG. 1) is detached from the heating cylinder 15.
Next, as shown in FIG. 3, a preparation step S02 is performed. That is, as shown in FIG. 4B, the lower member 31 and the upper member 32 of the screw maintenance jig 30 are jointed together and fastened together with the bolts 42 and 42 to form the pipe-shaped screw accommodation portion 43 from the lower pipe division member 34 and the upper pipe division member 38. Then, hooks 45 and 45 are hooked onto the suspension portions 40 and 40 (that is, the eyebolts), and the screw maintenance jig 30 is suspended by a crane (not shown). Then, the screw maintenance jig 30 is transported by the crane, and the screw accommodation portion 43 is disposed downstream of the heating cylinder 15 as shown in FIG. 4C.
Next, as shown in FIG. 3, a screw detaching step S03 is performed. That is, as shown in FIG. 4D, extrusion rods 47, 47, ... are inserted into the heating cylinder 15 from the upstream side of the heating cylinder 15, and the screw 16 is extruded. Then, the screw 16 is inserted into the screw accommodation portion 43 of the screw maintenance jig 30. The screw 16 is very hot and has a magnesium alloy or the like that is easily combusted adhered thereto, but the screw 16 extruded from the heating cylinder 15 is quickly inserted into the screw accommodation portion 43 to prevent contact with the atmosphere. This prevents combustion.
When the screw 16 is completely inserted and accommodated in the screw accommodation portion 43, a transportation step S04 is performed as shown in FIG. 3. That is, as shown in FIG. 4E, the screw maintenance jig 30 into which the screw 16 is inserted is transported to a predetermined maintenance work area by the crane. FIG. 4F shows the screw maintenance jig 30 after being transported and placed in the maintenance work area. In this state, a cooling step S05 shown in FIG. 3 is performed. That is, in a state in which the screw 16 is accommodated in the screw accommodation portion 43, the screw 16 is kept from coming into contact with the atmosphere while waiting for cooling.
When the screw 16 is completely cooled, a screw removing step S06 shown in FIG. 3 is performed. Specifically, as shown in FIG. 4G, the bolts 42 and 42 of the screw maintenance jig 30 are loosened. Then, the upper member 32 can be separated from the lower member 31. That is, the lower pipe division member 34 and the upper pipe division member 38 are separated, and the screw 16 is exposed. Thereafter, the screw 16 is taken out by a transporting unit such as the crane, and necessary maintenance such as cleaning of the screw 16 is performed. The maintenance of the screw 16 is completed by the above procedure.

[Comparative Example]

A screw maintenance jig 100 according to a comparative example will be described with reference to FIGS. 5A and 5B. The screw maintenance jig 100 according to the comparative example includes a screw accommodation portion 101 formed of a metal pipe and eyebolts 102 and 102 attached to the screw accommodation portion 101. With the screw maintenance jig 100 according to the comparative example, for example, as illustrated in FIGS. 4C and 4D, the screw maintenance jig 100 is disposed on the downstream side of the heating cylinder 15, and the screw 16 can also be accommodated in the screw maintenance jig 100 so as not to come into contact with the atmosphere as much as possible. FIG. 5A shows a state in which the screw maintenance jig 100 according to the comparative example with the screw 16 accommodated therein is suspended by a crane (not shown) including hooks 104 and 104.
However, a problem occurs when removing the screw 16 after the screw 16 is cooled. In the screw maintenance jig 100 according to the comparative example, the screw accommodation portion 101 is not designed to be opened. Therefore, it is necessary to remove the screw 16 from either of open ends of the screw accommodation portion 101. Therefore, for example, as shown in FIG. 5B, the hook 104 is hooked on only one eyebolt 102, and the screw maintenance jig 100 is suspended by the crane. Then, the screw 16 starts to slide out obliquely from the screw accommodation portion 101 due to its own weight. In this way, the screw 16 can be removed.
However, in this removal method, the screw 16 may unintentionally drop onto a floor surface, or the removed screw 16 may slip along the floor surface. In particular, in the case of a heavy screw 16, there is a high possibility of such drop or the like. In addition, when the screw accommodation portion 101 is inclined obliquely, a part of the magnesium alloy or the like adhering to the screw 16 turns into powder and scatters in a large amount around the screw maintenance jig 100. As a result, it is difficult to improve the efficiency of the removal work. On the other hand, by using the screw maintenance jig 30 (see FIG. 3A) according to the first embodiment, the screw 16 can be safely removed without the above-described drop or the like. Further, by using the screw maintenance jig 30, the magnesium alloy or the like adhering to the screw 16 is not scattered in a large amount into the surrounding area.

[Second Embodiment]

A screw maintenance jig 30A according to a second embodiment will be described with reference to FIG. 6A. Similarly to the first embodiment, the screw maintenance jig 30A according to the second embodiment includes a pair of pipe division members 51 and 51 having a shape (a so-called two-division shape) obtained by dividing a metal cylindrical pipe by a plane parallel to a cylindrical axis thereof (specifically, a plane having the cylindrical axis on the plane). The pair of pipe division members 51 and 51 are coupled to each other by a plurality of hinge structures 52, 52, ... Each of the pair of pipe division members 51 and 51 is provided with two suspension portions 54 and 54.
In the screw maintenance jig 30A according to the second embodiment, when the screw maintenance jig 30A is hung by a crane (not shown) using a hook (not shown) hooked on each of the suspension portions 54, 54, ..., the pair of pipe division members 51, 51 are rotated about the hinge structures 52, 52, ... to close each other and are arranged close to each other. As a result, a screw accommodation portion 43A having the shape of a single metal cylindrical pipe is formed. On the other hand, when the suspension portions 54, 54, ... are removed from the hook, the pair of pipe division members 51, 51 are opened and arranged apart from each other as shown in FIG. 6A. As a result, the inside of the screw accommodation portion 43A is opened.
When the screw 16 (see FIG. 1) is maintained using the screw maintenance jig 30A according to the second embodiment, maintenance may be performed in substantially the same manner as the screw maintenance method performed using the screw maintenance jig 30 (see FIGS. 2A and 2B) according to the first embodiment. That is, as shown in FIG. 3, the injection device rotating step S01, the preparation step S02, ..., and the screw removing step S06 are performed.
When the screw maintenance jig 30A (see FIG. 6A) according to the second embodiment is used, in the preparation step S02, a hook is attached to each of the suspension portions 54, 54, ... and the screw maintenance jig 30A is suspended by a crane to form the screw accommodation portion 43A. In addition, the cooling step S05 is performed without removing the hooks from the suspension portions 54, 54, ... That is, the screw 16 is cooled while maintaining the state in which the pair of pipe division members 51 and 51 form the pipe-shaped screw accommodation portion 43A. Alternatively, the suspension portions 54, 54, ... may be fixed using a predetermined fastener or the like to maintain the state in which the pair of pipe division members 51, 51 form the pipe-shaped screw accommodation portion 43A. In the screw removing step S06, the hooks are removed from the suspension portions 54, 54, ... Alternatively, the fastener or the like is removed. Then, the screw 16 (see FIG. 1) accommodated in the screw accommodation portion 43A is exposed, and the screw 16 can be taken out.

[Third Embodiment]

FIG. 6B shows a screw maintenance jig 30B according to a third embodiment. The screw maintenance jig 30B according to the third embodiment includes one two-division pipe division member 56 and two four-division pipe division members 57 and 57. The two-division pipe division member 56 has a shape (a so-called two-division shape) obtained by dividing a metal cylindrical pipe by a first plane parallel to a cylindrical axis thereof (specifically, a plane having the cylindrical axis on the plane). The four-division pipe division members 57 and 57 have a shape (a so-called four-division shape) obtained by dividing the other two-division pipe division member by a second plane parallel to the cylindrical axis and orthogonal to the first plane (specifically, a plane orthogonal to the plane and having the cylindrical axis on the plane). The four-division pipe division members 57 and 57 are coupled to both circumferential ends of the two-division pipe division member 56 via the hinge structures 52, 52, ... The two four-division pipe division members 57 and 57 are each provided with the suspension portions 54 and 54.
In the screw maintenance jig 30B according to the third embodiment, similarly to the screw maintenance jig 30A (see FIG. 6A) according to the second embodiment, when the screw maintenance jig 30B is hung by a crane (not shown) using a hook (not shown) hooked on each of the suspension portions 54, 54, ..., the two-division pipe division member 56 and the four-division pipe division members 57 and 57 are arranged close to each other to form a screw accommodation portion 43B. Further, when the suspension portions 54, 54, ... are removed from the hooks, as shown in FIG. 6B, the two-division pipe division member 56 and the four-division pipe division members 57 and 57 are arranged apart from each other, and the inside of the screw accommodation portion 43B is opened. The screw maintenance jig 30B according to the third embodiment can also maintain the screw 16 (see FIG. 1) in the same manner as the screw maintenance method using the screw maintenance jig 30 according to the first embodiment, and thus the description of the screw maintenance method will be omitted.

[Fourth Embodiment]

FIGS. 7A and 7B show a screw maintenance jig 30C according to a fourth embodiment. The screw maintenance jig 30C according to the fourth embodiment includes a pair of pipe division members 60 and 60 having a shape (a so-called two-division shape) obtained by dividing a metal cylindrical pipe by a plane parallel to a cylindrical axis thereof (specifically, a plane having the cylindrical axis on the plane). The pair of pipe division members 60 and 60 are coupled to each other by the hinge structures 52, 52, ..., and are rotatable about the hinge structures 52, 52, ... In the screw maintenance jig 30C according to the fourth embodiment, operation levers 61 and 61 are provided on the pair of pipe division members 60 and 60, respectively. The operation levers 61, 61, ... intersect each other, and the suspension portions 54, 54, ... are formed at tip ends of the operation levers 61, 61, ...
In the screw maintenance jig 30C according to the fourth embodiment, as shown in FIG. 7A, the screw maintenance jig 30C is lifted upward by a crane (not shown) with the hooks 45 and 45 hooked on the suspension portions 54, 54, ... Then, a gap between the operation levers 61, 61, ... (that is, a gap between the suspension portions 54, 54, ...) shown on the left and right in FIG. 7A is narrowed. As a result, the pair of pipe division members 60 and 60 are disposed close to each other to form a screw accommodation portion 43C. FIG. 7A shows a state in which the screw 16 is inserted and accommodated in the screw accommodation portion 43C. On the other hand, when the gap between the left and right operation levers 61, 61, ... (that is, the gap between the suspension portions 54, 54, ...) is widened, as shown in FIG. 7B, the pair of pipe division members 60 and 60 are arranged apart from each other. Then, the inside of the pipe is opened so that the screw 16 can be taken out.
The screw maintenance jig 30C according to the fourth embodiment also includes a locking unit. Specifically, a lock bar 63 is rotatably supported by operation levers 61, ... fixed to one of the pipe division members 60. The lock bar 63 is formed with a first protrusion 65 and a second protrusion 66. As illustrated in FIG. 7A, when the lock bar 63 is lowered in a state where the pair of pipe division members 60 and 60 are closed, the first protrusion 65 comes into contact with the operation lever 61. Then, the left and right operation levers 61, 61, ... are not opened. That is, the pair of pipe division members 60 and 60 are maintained in the closed state. On the other hand, as illustrated in FIG. 7B, when the lock bar 63 is lowered in a state where the pair of pipe division members 60 and 60 are separated from each other, the second protrusion 66 comes into contact with the operation lever 61. Then, the left and right operation levers 61, 61, ... are not closed. That is, the pair of pipe division members 60 and 60 are maintained in an open state.

Various modifications may be made to the screw maintenance jig 30, 30A, ... according to the first to fourth embodiments. For example, FIG. 8 shows screw maintenance jigs 30' and 30' according to a modification of the first embodiment. The screw maintenance jigs 30' and 30' according to this modification have a shorter length in the axial direction than the screw maintenance jig 30 according to the first embodiment, but the configuration thereof is similar to that of the screw maintenance jig 30 (see FIGS. 2A and 2B) according to the first embodiment. Therefore, the description of the configuration of the screw maintenance jigs 30' and 30' will be omitted. In this example, the screw accommodation portions 43 of the screw maintenance jigs 30' and 30' are arranged continuously in a direction of the cylindrical axis, and the screw 16 is inserted and accommodated in a series of cylindrical spaces formed by the plurality of screw accommodation portions 43.
Other modifications can be made. In each of the screw maintenance jigs 30, 30A, ... according to the first to fourth embodiments, the suspension portions 54, 54, ... are arranged at two different positions in a cylindrical axis direction of the screw accommodation portions 43, 43A, ... However, the suspension portions 54, 54, ... may be arranged at three or four or more positions in the cylindrical axis direction of the screw accommodation portions 43, 43A, ...
The terms "joined" and "arranged closely" in the present disclosure will be described. In the present disclosure, when forming the pipe-shaped screw accommodation portion (the screw accommodation portion 43, the screw accommodation portion 43A, the screw accommodation portion 43B, and the screw accommodation portion 43C), as shown in FIG. 2B, a plurality of pipe division members (the lower pipe division member 34 and the upper pipe division member 38) may be "joined" together to bring the pipe division members into close contact with each other by reducing a gap between the pipe division members as much as possible, or as shown in FIGS. 6A, 6B, and 7A, a plurality of pipe division members (the pipe division member 51, the two-division pipe division member 56, the four-division pipe division members 57, and the pipe division member 60) may be "arranged closely" so as to arrange the pipe division members adjacent to each other, allowing for a gap with such a size that the screw 16 does not pass between the pipe division members.
The terms "separated" and the "arranged apart" in the present disclosure will be described. In the present disclosure, when the inside of the pipe-shaped screw accommodation portion (the screw accommodation portion 43, the screw accommodation portion 43A, the screw accommodation portion 43B, and the screw accommodation portion 43C) is opened, as shown in FIG. 4G, the plurality of pipe division members (the lower pipe division member 34 and the upper pipe division member 38) may be "separated" so as to be positioned at separate places without being connected to each other by a hinge structure or the like, or as shown in FIGS. 6A, 6B, and 7B, the plurality of pipe division members (the pipe division member 51, the two-division pipe division member 56, the four-division pipe division members 57, and the pipe division member 60) may be "arranged apart" so as to be positioned at separate places in a state where the pipe division members are connected to each other by the hinge structure 52.
Although the invention made by the present inventor has been specifically described above based on the embodiments, it is needless to say that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the scope of the invention. The plurality of examples described above may be appropriately combined.
Here, the features of the screw maintenance jig 30, 30A, 30B, 30C, 30' and the screw maintenance method described above will be briefly summarized and listed in the following [1] to [9].

[1] A screw maintenance jig (30, 30A, 30B, 30C, 30') for a metal injection molding machine (1) that is for maintaining a screw (16) of the metal injection molding machine, the screw maintenance jig (30, 30A, 30B, 30C, 30') including:
- a pipe-shaped screw accommodation portion (43, 43A, 43B, 43C) configured to accommodate the screw (16) inserted therein; and
- a plurality of suspension portions (40, 54) provided for the screw accommodation portion (43, 43A, 43B, 43C),
- in which the screw accommodation portion (43, 43A, 43B, 43C) includes a plurality of pipe division members (34, 38, 51, 56, 57, 60) each having a shape obtained by dividing the screw accommodation portion (43, 43A, 43B, 43C) by a plane that is parallel to a cylindrical axis of the screw accommodation portion (43, 43A, 43B, 43C) or a plane that includes the cylindrical axis within the plane, and
- in which the screw accommodation portion is configured such that when the plurality of pipe division members (34, 38, 51, 56, 57, 60) are arranged close to each other or joined together, the pipe-shaped screw accommodation portion (43, 43A, 43B, 43C) is formed, and when at least some of the pipe division members (34, 38, 51, 56, 57, 60) are arranged apart from each other or separated, an inside of the screw accommodation portion (43, 43A, 43B, 43C) is opened.
[2] The screw maintenance jig (30) for a metal injection molding machine according to [1], further including:
- a plurality of coupling brackets (35, 39) provided on each of the plurality of pipe division members (34, 38),
- in which the plurality of pipe division members (34, 38) form the pipe-shaped screw accommodation portion (43) by coupling the plurality of coupling brackets (35, 39), and
- in which the suspension portion (40) is provided on each of the plurality of coupling brackets (35, 39) which are provided on at least some of the pipe division members (34, 38).
[3] In the screw maintenance jig (30A, 30B, 30C) for a metal injection molding machine according to [1],
the plurality of pipe division members (51, 56, 57, 60) are coupled to each other by a hinge structure (52).
[4] In the screw maintenance jig (30A, 30B, 30C) for a metal injection molding machine according to [3],
- the suspension portion (54) is provided on one of the pipe division members (51, 56, 57, 60) and on another one of the pipe division members (51, 56, 57, 60), and
- when the suspension portion (54) of the one of the pipe division members (51, 56, 57, 60) and the suspension portion (54) of the another of the pipe division members (51, 56, 57, 60) are hooked on a predetermined external hook to suspend the screw maintenance jig (30A, 30B, 30C), the plurality of pipe division members (51, 56, 57, 60) form the pipe-shaped screw accommodation portion (43A, 43B, 43C).
[5] The screw maintenance jig (30C) for a metal injection molding machine according to [4], further including:
- a lock portion (63),
- in which when the suspension portion (54) of the one of the pipe division members (60) and the suspension portion (54) of the another one of the pipe division members (60) are fixed by the lock portion (63) so as not to move relative to each other, a state in which the plurality of pipe division members (60) form the pipe-shaped screw accommodation portion (43C) is maintained.
[6] In the screw maintenance jig (30A, 30C) for a metal injection molding machine according to [1],
- the screw accommodation portion (43A, 43C) includes a pair of the pipe division members (51, 60) each having a shape obtained by dividing the screw accommodation portion (43A, 43C) by a plane that includes the cylindrical axis within the plane,
- the pair of pipe division members (51, 60) are coupled to each other by a hinge structure (52),
- the suspension portion (54) is provided on each of the pair of pipe division members (51, 60),
- when a gap between the suspension portion (54) of one of the pipe division members (51, 60) and the suspension portion (54) of the other of the pipe division members (51, 60) is increased, an inside of the screw accommodation portion (43A, 43C) is opened, and
- when the gap is narrowed, the pipe-shaped screw accommodation portion (43A, 43C) is formed.
[7] The screw maintenance jig (30') for a metal injection molding machine according to [1] or [2], including:
- a plurality of the screw accommodation portions (43),
- in which the plurality of screw accommodation portions (43) are arranged continuously in a direction of the cylindrical axis, and the screw (16) is accommodated in a series of cylindrical spaces formed by the plurality of screw accommodation portions (43).
[8] A screw maintenance method for a metal injection molding machine (1) that maintains a screw (16) of the metal injection molding machine using a screw maintenance jig (30, 30A, 30B, 30C, 30'),
- the screw maintenance jig (30, 30A, 30B, 30C, 30') including:
  - a pipe-shaped screw accommodation portion (43, 43A, 43B, 43C) configured to accommodate the screw (16) inserted therein; and
  - a plurality of suspension portions (40, 54) provided for the screw accommodation portion (43, 43A, 43B, 43C),
- the screw accommodation portion (43, 43A, 43B, 43C) including a plurality of pipe division members (34, 38, 51, 56, 57, 60) each having a shape obtained by dividing the screw accommodation portion (43, 43A, 43B, 43C) by a plane that is parallel to a cylindrical axis of the screw accommodation portion (43, 43A, 43B, 43C) or a plane that includes the cylindrical axis within the plane,
- the screw accommodation portion (43, 43A, 43B, 43C) being configured such that when the plurality of pipe division members (34, 38, 51, 56, 57, 60) are arranged close to each other or joined together, the pipe-shaped screw accommodation portion (43, 43A, 43B, 43C) is formed, and when at least some of the pipe division members (34, 38, 51, 56, 57, 60) are arranged apart from each other or separated, an inside of the screw accommodation portion (43, 43A, 43B, 43C) is opened,
- the screw maintenance method including:
  - a preparation step including hooking the suspension portions (40, 54) onto a predetermined external hook (45) to suspend the screw maintenance jig (30, 30A, 30B, 30C, 30') in a state where the pipe-shaped screw accommodation portion (43, 43A, 43B, 43C) is formed by the plurality of pipe division members (34, 38, 51, 56, 57, 60), and disposing the screw accommodation portion (43, 43A, 43B, 43C) downstream of a heating cylinder (15) of the metal injection molding machine (1);
  - a screw detaching step including inserting an extrusion rod (47) into the heating cylinder (15) from an upstream side to extrude the screw (16) on a downstream side, and inserting and accommodating the screw (16) in the screw accommodation portion (43, 43A, 43B, 43C);
  - a transportation step including transporting the screw maintenance jig (30, 30A, 30B, 30C, 30') with the screw (16) accommodated in the screw accommodation portion (43, 43A, 43B, 43C) to a maintenance work area;
  - a cooling step including waiting for the screw (16) to cool while the screw (16) is accommodated in the screw accommodation portion (43, 43A, 43B, 43C); and
  - a screw removing step including opening the inside of the screw accommodation portion (43, 43A, 43B, 43C) and removing the screw (16).
[9] The screw maintenance method for a metal injection molding machine according to [8], further including:
- an injection device rotating step that is performed prior to the preparation step,
- in which the injection device rotating step is a step of rotating an injection device (3) of the metal injection molding machine (1) to separate a downstream end of the heating cylinder (15) from a mold clamping device of the metal injection molding machine (1).

The present application is based on Japanese Patent Application No. 2022-157577 filed on September 30, 2022, and the contents thereof are incorporated herein as reference.

INDUSTRIAL APPLICABILITY

The screw maintenance jig and the screw maintenance method according to the present invention can prevent contact between a screw and the atmosphere as much as possible when the screw is taken out for cooling, and can easily expose the screw after the cooling. The present invention having this effect can be used, for example, in the maintenance of a screw of a metal injection molding machine.

REFERENCE SIGNS LIST

1: Metal injection molding machine
2: Mold clamping device
3: Injection device
5: Fixed platen
6: Movable platen
7: Mold clamping housing
9: Tie bar
10: Toggle mechanism
12: Fixed mold
13: Movable mold
15: Heating cylinder
16: Screw
17: Screw driving device
18: Base
19: Rotation shaft
21: Hopper
22: Injection nozzle
30: Screw maintenance jig
31: Lower member
32: Upper member
34: Lower pipe division member
35: Lower coupling bracket
36: Bolt hole
38: Upper pipe division member
39: Upper coupling bracket
40: Suspension portion
42: Bolt
43: Screw accommodation portion
45: Hook
51: Pipe division member
52: Hinge structure
54: Suspension portion
56: Two-division pipe division member
57: Four-division pipe division member
60: Pipe division member
61: Operation lever
63: Lock bar
65: First protrusion
66: Second protrusion

Claims

A screw maintenance jig for a metal injection molding machine that is for maintaining a screw of the metal injection molding machine, the screw maintenance jig comprising:
a pipe-shaped screw accommodation portion configured to accommodate the screw inserted therein; and

a plurality of suspension portions provided for the screw accommodation portion,

wherein the screw accommodation portion includes a plurality of pipe division members each having a shape obtained by dividing the screw accommodation portion by a plane that is parallel to a cylindrical axis of the screw accommodation portion or a plane that includes the cylindrical axis within the plane, and

wherein the screw accommodation portion is configured such that when the plurality of pipe division members are arranged close to each other or joined together, the pipe-shaped screw accommodation portion is formed, and when at least some of the pipe division members are arranged apart from each other or separated, an inside of the screw accommodation portion is opened.
The screw maintenance jig for a metal injection molding machine according to claim 1, further comprising:
a plurality of coupling brackets provided on each of the plurality of pipe division members,

wherein the plurality of pipe division members form the pipe-shaped screw accommodation portion by coupling the plurality of coupling brackets, and

wherein the suspension portion is provided on each of the plurality of coupling brackets which are provided on at least some of the pipe division members.
The screw maintenance jig for a metal injection molding machine according to claim 1,
wherein the plurality of pipe division members are coupled to each other by a hinge structure.
The screw maintenance jig for a metal injection molding machine according to claim 3,
wherein the suspension portion is provided on one of the pipe division members and on another of the pipe division members, and

wherein when the suspension portion of the one of the pipe division members and the suspension portion of the another one of the pipe division members are hooked on a predetermined external hook to suspend the screw maintenance jig, the plurality of pipe division members form the pipe-shaped screw accommodation portion.
The screw maintenance jig for a metal injection molding machine according to claim 4, further comprising:
a lock portion,

wherein when the suspension portion of the one of the pipe division members and the suspension portion of the another one of the pipe division members are fixed by the lock portion so as not to move relative to each other, a state in which the plurality of pipe division members form the pipe-shaped screw accommodation portion is maintained.
The screw maintenance jig for a metal injection molding machine according to claim 1,
wherein the screw accommodation portion includes a pair of the pipe division members each having a shape obtained by dividing the screw accommodation portion by a plane that includes the cylindrical axis within the plane,

wherein the pair of pipe division members are coupled to each other by a hinge structure,

wherein the suspension portion is provided on each of the pair of pipe division members,

wherein when a gap between the suspension portion of one of the pipe division members and the suspension portion of the other of the pipe division members is increased, an inside of the screw accommodation portion is opened, and

wherein when the gap is narrowed, the pipe-shaped screw accommodation portion is formed.
The screw maintenance jig for a metal injection molding machine according to claim 1 or 2, comprising:
a plurality of the screw accommodation portions,

wherein the plurality of screw accommodation portions are arranged continuously in a direction of the cylindrical axis, and the screw is accommodated in a series of cylindrical spaces formed by the plurality of screw accommodation portions.
A screw maintenance method for a metal injection molding machine that maintains a screw of the metal injection molding machine using a screw maintenance jig,
the screw maintenance jig including:
a pipe-shaped screw accommodation portion configured to accommodate the screw inserted therein; and

a plurality of suspension portions provided for the screw accommodation portion,

the screw accommodation portion including a plurality of pipe division members each having a shape obtained by dividing the screw accommodation portion by a plane that is parallel to a cylindrical axis of the screw accommodation portion or a plane that includes the cylindrical axis within the plane,

the screw accommodation portion being configured such that when the plurality of pipe division members are arranged close to each other or joined together, the pipe-shaped screw accommodation portion is formed, and when at least some of the pipe division members are arranged apart from each other or separated, an inside of the screw accommodation portion is opened,

the screw maintenance method comprising:
a preparation step including hooking the suspension portions onto a predetermined external hook to suspend the screw maintenance jig in a state where the pipe-shaped screw accommodation portion is formed by the plurality of pipe division members, and disposing the screw accommodation portion downstream of a heating cylinder of the metal injection molding machine;

a screw detaching step including inserting an extrusion rod into the heating cylinder from an upstream side to extrude the screw on a downstream side, and inserting and accommodating the screw in the screw accommodation portion;

a transportation step including transporting the screw maintenance jig with the screw accommodated in the screw accommodation portion to a maintenance work area;

a cooling step including waiting for the screw to cool while the screw is accommodated in the screw accommodation portion; and

a screw removing step including opening the inside of the screw accommodation portion and removing the screw.
The screw maintenance method for a metal injection molding machine according to claim 8, further comprising:
an injection device rotating step that is performed prior to the preparation step,

wherein the injection device rotating step is a step of rotating an injection device of the metal injection molding machine to separate a downstream end of the heating cylinder from a mold clamping device of the metal injection molding machine.