JP2015020370A - Metal mold for tubular molded body and tubular molded body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal mold in which a synthetic-resin-made tubular molded body that is excellent in dimensional accuracy can be injection-molded.SOLUTION: A synthetic-resin-made tubular molded body 1 is injection-molded by a metal mold 2. The metal mold 2 includes a stationary side metal mold 21 which specifies the shape of a first end surface 12 of the tubular molded body 1, a moving side metal mold 22 which specifies the shape of a second end surface 13 of the tubular molded body, slide metal molds 23, 23 which are arranged between the stationary side metal mold 21 and the moving side metal mold 22 and specify the shape of a part of the tubular outer peripheral surface 14 of the tubular molded body, and a core metal mold 24 which specifies the shape of the inner peripheral surface 15 of the tubular molded body. The tubular molded body 1 includes ring-shaped groove parts 11 on the tubular outer peripheral surface 14 and the slide metal molds 23, 23 specify at least the shapes of the groove parts 11. The shape of the tubular outer peripheral surface 14 of the area (A) which is nearer to the first end surface 12 than the groove part 11 which is nearest to the first end surface 12 is specified by the stationary side metal mold 21, and a disk gate is constructed by arranging the end surface of the core metal mold 24 as facing to the resin injecting port S of the stationary side metal mold 21.

Description

The present invention relates to a mold used for injection molding of a synthetic resin. In particular, the present invention relates to a mold for forming a tubular molded body formed into a hollow tubular shape.

A tubular molded body may be used as a connector member for connecting a conduit such as a tube. For example, in a hydraulic circuit, a liquid feed circuit, etc., pipe blocks provided with pipe lines are arranged opposite to each other, and the pipe lines provided in the respective pipe blocks are connected to each other by a tubular molded body. The technology of making a series of pipelines is used. For example, such a pipe block or pipe connection structure is adopted in a hydraulic circuit of an automatic transmission of an automobile, a refrigerant circulation circuit of an air conditioner, or the like. A ring-shaped groove for holding a sealing material (such as an O-ring) is often formed in a tubular molded body used for a connector member.

For example, Patent Document 1 has a flange portion on the outer periphery of the intermediate portion in the length direction when mutually connecting the passages (exit, connection port) of the liquid tank and the double pipe joint block to be coupled to each other. In the state where the connecting pipe portions at both ends of the pipe joint (connector member, that is, the tubular molded body) are inserted into the opening ends of the passages through the O-rings, and the flange portions are accommodated in the annular accommodating recesses provided in the block, A technique for sandwiching a liquid tank and a double pipe joint block between joint surfaces is disclosed. According to the connector member and the connection structure, it is disclosed that the cost can be reduced with a simple configuration.

Further, the tube resin joint disclosed in Patent Document 2 has one end formed at a connection portion with the tube and the other end formed at a screw connection portion, and a space between them is formed in a ring-like groove shape. Patent Document 2 discloses that such a resin joint is injection-molded using insert molding using a mold that is split along the axial direction of the joint.

JP 2005-207463 A JP 2005-125757 A

The inventors studied to form a hollow tubular connector member having a ring-shaped groove on the outer peripheral surface by injection molding of a synthetic resin. If a ring-shaped groove is formed on the outer peripheral surface of the hollow tubular molded body, the groove is undercut, so that it cannot be removed from the mold along the axis of the molded body. Therefore, in the prior art, as disclosed in FIGS. 3 to 7 of Patent Document 2, the mold forming the cylindrical outer peripheral surface of the tubular molded body is divided by a plane including the molded body axis. Thus, the mold is opened in a direction perpendicular to the axis direction of the molded body, and the molded body is taken out.

However, on the mating surfaces of the molds, steps and burrs are easily generated in the molded body, and it is difficult to increase the dimensional accuracy of the molded body. Especially when the required accuracy of the end of the tubular molded body is high, such as when directly connecting a resin tube or the like to the end of the tubular molded body, or when the clearance with the counterpart member to which the tubular molded body is assembled is small, With a mold as disclosed in Patent Document 2, it has been difficult to obtain a tubular molded body with a desired accuracy.
Further, in the mold as disclosed in Patent Document 2, if the mold adjustment for preventing the occurrence of steps and burrs is repeated, the outer dimension of the molded body changes, and it is necessary to recreate the entire mold. There was also a problem that it was difficult to adjust the mold.

An object of the present invention is to provide an injection mold capable of forming a synthetic resin tubular molded body having excellent dimensional accuracy.

As a result of intensive studies, the inventor has found that the above object can be achieved by combining part of the cylindrical outer peripheral surface of the tubular molded body with a fixed mold and injection of resin with a disk gate. As a result, the present invention has been completed.

The present invention is a mold for molding a hollow tubular tubular molded body by injection molding of a synthetic resin, and a fixed-side mold that at least defines the shape of a first end face that is one end face of the tubular molded body, The movable side mold defining at least the shape of the second end surface, which is the other end face of the tubular molded body, and the cylindrical outer peripheral surface of the tubular molded body disposed between the fixed side mold and the movable side mold. A slide mold that defines a part of the shape and is movable in a direction that intersects the mold opening direction as the mold is opened and closed, and a core mold that defines the shape of the inner peripheral surface of the tubular molded body The tubular molded body has at least one ring-shaped groove on the cylindrical outer peripheral surface, and the slide mold defines at least the shape of the groove on the cylindrical outer peripheral surface. A region closer to the first end surface than the groove closest to the first end surface This is a mold for tubular molded bodies in which the shape of the cylindrical outer peripheral surface is defined by the fixed side mold, and the end face of the core mold is arranged opposite to the resin injection port of the fixed side mold to constitute a disk gate. (First invention).

In the first invention, two or more ring-shaped groove portions are formed, and the moving side mold may define the shape of the cylindrical outer peripheral surface in the region closer to the second end surface than the groove portion closest to the second end surface. Preferred (second invention). Moreover, this invention is the tubular molded object injection-molded using the metal mold | die of 1st invention or 2nd invention.

According to the mold for tubular molded bodies of the present invention (first invention), the dimensional accuracy of the tubular molded body to be injection molded can be increased. Moreover, if it is made like 2nd invention, the dimensional accuracy of the both ends of a tubular molded object can be improved, and a dimensional accuracy can be raised more effectively.

It is a figure which shows the tubular molded object of 1st Embodiment. It is a schematic diagram which shows the structure of the metal mold | die for shape | molding the tubular molded object of 1st Embodiment in a mold closed state. It is a schematic diagram which shows the structure of the metal mold | die for shape | molding the tubular molded object of 1st Embodiment in a mold open state. It is a figure which shows the tubular molded object of 2nd Embodiment. It is a schematic diagram which shows the structure of the metal mold | die for shape | molding the tubular molded object of 2nd Embodiment in a mold closed state.

Hereinafter, an embodiment of the present invention will be described by taking a connector member used in a hydraulic circuit of an automatic transmission of an automobile as an example with reference to the drawings. The present invention is not limited to the individual embodiments shown below, and can be carried out by changing the form.

FIG. 1 shows a tubular molded body 1 (hereinafter also referred to as “connector member”) of the first embodiment. The left view of FIG. 1 is shown as a cross-sectional view along the axis of the tube, and the right view is shown as an external view of the end of the tube. The connector member 1 is a member made of synthetic resin, and is formed into a straight tube having a cylindrical cross section by injection molding. That is, the connector member 1 is formed in a hollow tubular shape, and the connector member includes end surfaces 12 and 13 located at both ends in the longitudinal direction of the tubular body, a cylindrical cylindrical outer peripheral surface 14, and a cylindrical inner surface. A peripheral surface 15 is provided.

Seal grooves 11 and 11 are provided in the vicinity of both ends in the length direction of the cylindrical outer peripheral surface 14 of the connector member 1, respectively. In the present embodiment, two seal grooves 11 are formed as ring-shaped grooves having a substantially rectangular groove cross section. That is, at least one ring-shaped groove is provided on the cylindrical outer peripheral surface of the connector member 1. An O-ring, which will be described later, is attached to the seal groove 11, and the connector member and the mating member are sealed by the O-ring.

The connector member 1 is a member formed by synthetic resin injection molding. The connector member 1 has a gate mark 16 corresponding to the gate from which resin is injected during injection molding. The gate mark 16 exists in a ring shape on the inner peripheral surface side of the connector member 1. That is, in the molding of the connector member 1, the resin is injected by a disk gate connected to the inner peripheral surface side of the connector member 1. The gate mark 16 is present at the end of the connector member 1 in the length direction (tube axis direction), that is, at a position close to the tube end.

In particular, in the present embodiment, the gate mark 16 exists at the tube end of the connector member 1 in the tube axis direction. It is preferable that the gate mark 16 is provided at the pipe end because the structure of the injection mold is simple and the manufacturing efficiency is improved.
In the present embodiment, the gate mark 16 is provided on the inner peripheral surface 15 of the connector member 1. If the gate mark 16 is provided on the inner peripheral surface of the pipe, that is, if the disk gate is injection-molded so as to be connected to the inner peripheral surface of the tubular molded body, the disk gate can be easily cut. When the gate mark is provided on the inner peripheral surface of the tubular molded body, the gate mark 16 obtained by cutting the disk gate is suppressed from jumping out to the end surface of the connector member 1, and the lengthwise dimension of the connector member 1. Can be molded more accurately.

The synthetic resin constituting the connector member 1 is not particularly limited as long as it is a resin that can be molded by injection molding. Preferably, an olefin resin such as a polypropylene resin, a thermoplastic resin such as a polyamide resin or an acrylonitrile butadiene styrene resin, a thermosetting resin such as a melamine resin, rubber, a thermoplastic elastomer, or the like can be used. The connector member 1 of this embodiment is formed of a polyamide resin.

The connector member 1 can connect the pipeline of the hydraulic circuit as disclosed in Patent Document 1 and the like. For example, the connector member 1 is interposed between the oppositely disposed pipeline blocks to connect the pipelines.
Here, the pipeline block is a member in which a pipeline is formed, and when a predetermined pipeline block is arranged opposite to each other in a predetermined positional relationship, the internal pipeline communicates to complete a series of pipelines. It is the member comprised so that it might do. The pipe block is typically made of an iron alloy, an aluminum alloy, a synthetic resin, or the like. A plurality of pipelines are preferably formed in the pipeline block. These conduits are typically formed by machining or the like.

The connector member 1 can be connected to each other by inserting both ends of the connector member 1 into the pipelines of the pipeline block in a state where the seal material (O-ring) is mounted in the seal groove 11. Note that the sealing material is not limited to the O-ring as long as the sealing portion can be sealed to the required level, and other sealing materials and seal structures may be used. For example, the elastomer material may be secondarily formed in the formed seal groove 11 portion, and the seal material may be integrally formed in the seal groove portion.

In this embodiment, the groove 11 provided on the cylindrical outer peripheral surface 14 of the tubular molded body 1 is a seal groove, but the purpose of the groove is not limited to the seal groove, and the groove 11 is used for locking. It may be a groove for other purposes such as a groove or a groove for labyrinth.

The manufacturing method of the connector member (tubular molded object) 1 and the metal mold | die used for manufacture are demonstrated. The connector member 1 is manufactured by resin injection molding. 2 and 3 show a mold 2 used for injection molding of the tubular molded body 1. FIG. 2 schematically shows a state where the mold 2 is closed, and FIG. 3 schematically shows a state where the mold 2 is opened. The mold 2 is provided with a set of cavity molds 21, 22, and 23 that form cavities having an inner surface shape that matches the outer surface shape of the tubular molded body 1, and the inner surface shape of the tubular molded body 1 is provided in the cavity mold. Is provided with a cylindrical core mold 24 corresponding to the above. 2 and 3 show the cavity molds 21, 22, 23 and the core mold 24 in cross-sectional views. 2 and 3, the cavity molds 21, 22, 23 and the core mold 24 are not hatched in order to make the drawings easier to see, and the cavity portions are hatched.

The structure of the mold 2 will be described in more detail. The cavity mold of the mold 2 includes a fixed mold 21, a moving mold 22, and slide molds 23 and 23. The fixed-side mold 21 is a mold that does not move with the opening and closing of the mold, or a mold that is disposed adjacent to the mold that does not move, and the fixed-side mold 21 contains a molten resin. Sprues S and runners that are injected into the cavity are provided. In the mold of the present embodiment, the fixed mold is a non-moving mold having a sprue S.

The moving side mold 22 is a mold provided so as to be movable in the mold opening direction (vertical direction in FIG. 2) with respect to the fixed side mold 21 as the mold is opened and closed. The slide molds 23 and 23 are provided between the fixed mold 21 and the movable mold 22, and in a direction intersecting with the mold opening direction (left and right direction in FIG. 2) as the mold 2 is opened and closed. Preferably, the mold is provided so as to be movable in a direction orthogonal to the mold opening direction. Further, the stationary mold 21 is provided with locking blocks 25 and 25 having inclined surfaces for closely contacting the slide molds 23 and 23 when the mold is closed.

The tubular molded body 1 is molded by the mold 2 in such a posture that the tube axis direction of the tubular molded body coincides with the mold opening direction of the mold 2.

The shape of the first end surface 12 that is one end surface of the tubular molded body 1 is defined by the fixed-side mold 21. That is, the stationary mold is a mold that defines at least the shape of the first end face 12 of the tubular molded body 1. Similarly, the shape of the second end face 13 which is the other end face of the tubular molded body 1 is defined by the moving side mold 22, that is, the moving side mold 22 is at least of the second end face 13 of the tubular molded body 1. A mold that defines the shape. In the present embodiment, the first end surface 12 and the second end surface 13 are formed in a planar shape, but the end surface shape may be defined in other forms such as a tapered surface shape, a curved surface shape, and an uneven shape.

The slide molds 23 and 23 are disposed between the fixed mold 21 and the movable mold 22 and define a part of the cylindrical outer peripheral surface 14 of the tubular molded body 1. In the present embodiment, the shapes of the ring-shaped groove portions 11 and 11 and the portion between the grooves in the cylindrical outer peripheral surface 14 of the tubular molded body 1 are defined by the slide molds 23 and 23. In FIG. 1, a region where the cylindrical outer peripheral surface 14 is formed by the slide molds 23 and 23 is shown as a section B. The slide molds 23 and 23 are provided so as to form a portion that becomes an undercut and prevents the mold removal, particularly when the tubular molded body 1 is to be removed along the tube axis direction. That is, the slide molds 23 and 23 are provided so as to define at least the shape of the groove portion of the cylindrical outer peripheral surface.

Note that the slide mold 23 may be configured to form only a portion that is undercut, but may be configured to include a portion that is not undercut as in the present embodiment. In this embodiment, the slide mold is divided into two parts. However, the slide mold may be divided into three parts or four or more parts as necessary.

A part of the cylindrical outer peripheral surface 14 is formed by the fixed mold 21. That is, the shape of the cylindrical outer peripheral surface 14 in the region closer to the first end surface 11 (the region indicated by section A in FIG. 1) than the groove 11 closest to the first end surface 12 formed by the fixed-side mold is It is defined by the fixed mold 21. That is, the fixed mold 21 is provided with a recess corresponding to the shape of the end portion on the first end face side of the tubular molded body.

Although not essential, in the present embodiment, a part of the cylindrical outer peripheral surface 14 is formed by the moving-side mold 22. That is, the shape of the cylindrical outer peripheral surface 14 in the region closer to the second end surface 13 (the region indicated by section C in FIG. 1) than the groove 11 closest to the second end surface 13 formed by the moving side mold is It is defined by the moving mold 22. That is, in this embodiment, the moving side mold 22 is provided with a recess corresponding to the end shape on the second end face side of the tubular molded body.

The core mold 24 is provided as a so-called core pin integrally with the moving side mold. The shape of the inner peripheral surface of the tubular molded body 1 is defined by the core mold 24. In the present embodiment, the core mold is formed in a columnar shape, and the formed inner peripheral surface is cylindrical. The shape of the inner peripheral surface may be other shapes such as a rectangular tube shape.

Furthermore, the end face of the core mold 24 is arranged so as to face the sprue S of the fixed mold 21 and leave a slight gap, and a disk-like space is formed in this portion, so-called disk gate is configured. ing. That is, the molten resin injected from the sprue S with respect to the closed mold is filled into the cavity in which the tubular molded body is to be formed through this disk-shaped space. If the disk gate can be configured, the end face of the core mold does not necessarily face the sprue S, and the end face of the core mold may face the runner provided in the fixed side mold 21. . That is, the disk gate may be configured such that the end surface of the core mold faces the resin injection port for injecting resin into the cavity.

The cavity molds 21, 22, 23 and the core mold 24 are appropriately provided with an opening / closing mechanism, a slide mechanism, an extrusion pin, and the like, and are capable of injection molding and taking out a molded product. Illustration and description are omitted.

In the injection molding process, resin is injected from the sprue S provided in the fixed mold 21. The injected resin passes through the disk gate formed by the end face of the core mold 24 and the cavity mold 21 and is supplied to the cavity space in which the tubular molded body 1 is formed.

After the resin is filled in the cavity and the resin is solidified, the mold is opened as shown in FIG. 3, and the tubular molded body (connector member) 1 is taken out. At this time, the disk gate portion is removed from the tubular molded body 1, and the gate mark 16 to which the disk gate portion is connected remains in the tubular molded body 1.

The timing between the mold opening and taking out of the molded product and the separation of the disc gate portion can be performed at various timings. For example, by making full use of the mold slide mechanism and adjusting the timing of injection molding and mold slide, before opening the mold, the disc gate part is cut off inside the mold, and then the mold is molded. You may make it open and take out a molded article. Alternatively, the disk gate portion may be separated when the mold is opened and the molded product is taken out by making full use of the mold slide mechanism and adjusting the timing of mold opening and mold slide. Alternatively, after injection molding, the molded product may be taken out while the tubular molded body 1 and the disk gate portion are integrated, and the disk gate portion may be separated from the tubular molded body 1 by post-processing.

The operation and effect obtained by the mold 2 will be described.
The end portion (A region or C region in FIG. 1) of the tubular molded body 1 is formed by a recess dug into the fixed mold 21 and the movable mold 22 during the injection molding using the mold 2. Since these are formed, there is no generation of burrs generated on the mold parting surface, and the outer surface shape of the tubular molded body is directly and accurately formed by the fixed mold 21 and the movable mold 22. Therefore, the mold 2 contributes to improving the dimensional accuracy of the end portion of the tubular molded body to be injection molded. When the dimensional accuracy and geometric shape of the end shape are severe, such as when the tubular molded body is inserted into a hole, the mold 2 produces a tubular molded body with particularly good dimensional accuracy. it can.

Further, in the part formed by the slide molds 23, 23, there is a possibility that burrs may occur on the parting surface. However, according to the mold 2, the tubular surface is adjusted even if the mating surface adjustment of this part is performed. There is no adverse effect on the dimensional accuracy of the end of the molded body. Therefore, it becomes easy to adjust the mating surface of the slide mold, and the dimensional accuracy of the molded body can be improved.

Further, the end face of the core mold 24 and the resin injection port (sprue or runner) of the fixed mold 21 are arranged so as to face each other to constitute a disk gate, and the part where the disk gate is connected to the cavity is fixed. Since the recess (provided that the end of the tubular molded body is formed only by the fixed mold) is provided in the side mold, the end of the tubular molded body where the disk gate does not have the mating surface of the mold Placed in the section. The vicinity of the gate is a part where the burrs are particularly likely to occur due to the high fluidity of the resin. However, according to the mold 2, the disk gate is disposed on the part without the mating surface of the mold. Is suppressed, contributing to the improvement of the dimensional accuracy of the tubular molded body.

With the above configuration, the resin injection force is radially distributed by the disk gate, and the resin injected from the disk gate is once received in the recess of the fixed mold 21 before the slide mold. Therefore, the momentum of the injection resin is effectively relieved, and the generation of burrs can be suppressed even at the mating surface of the slide mold portion.

Further, as in the present embodiment, the end portions (A region and C region) of the tubular molded body are molded by the fixed mold 21 and the movable mold 22 at both end faces 12 and 13 of the tubular molded body 1. If it makes it, generation | occurrence | production of a level | step difference and a burr | flash can be prevented in the both ends of a tubular molded object, and the length dimensional accuracy of a tubular molded object can be improved especially.

The present invention is not limited to the above embodiment, and can be implemented with various modifications. Other embodiments of the present invention will be described below. However, in the following description, portions different from the above embodiment will be mainly described, and detailed descriptions of the same portions will be omitted. In addition, these embodiments can be implemented by combining some of them or replacing some of them.

In FIG. 4, the tubular molded object (connector member) 3 of 2nd Embodiment of this invention is shown. In the present embodiment, the tubular molded body 3 has one ring-shaped groove 31 on the outer peripheral surface. The ring-shaped groove portion 31 is disposed so as to be biased toward the one end surface (first end surface) 32 of the tubular molded body 3. In addition, a ring-shaped gate mark 36 that is a disk gate trace exists on the inner peripheral surface side of the first end face. Thus, the number of ring-shaped grooves provided in the connector member may be one. Conversely, there may be three or more ring-shaped grooves.

In FIG. 5, the metal mold | die 4 used for injection molding of the tubular molded object 3 of 2nd Embodiment is shown. The basic configuration of the stationary mold 41, the moving mold 42, the slide molds 43 and 43, and the core mold 44 is the same as that of the mold 2 of the first embodiment. In addition, a disk gate is formed by facing the end surface of the core mold 44 and the sprue S of the fixed mold 41, or a recess is formed in the fixed mold 41. The point that the end portion on the first end face (32) side of the tubular molded body 3 is formed including the cylindrical outer peripheral surface of the D region shown is the same as that of the mold 2 of the first embodiment.

In the present embodiment, the moving side mold 42 forms only the end surface (second end surface 33) opposite to the first end surface of the tubular molded body 3, and the remaining portion of the cylindrical outer peripheral surface of the tubular molded body. (The groove portion 31 and the cylindrical outer peripheral surface from the groove portion to the second end surface: region E in FIG. 4) are all different from the first embodiment in that they are formed by the slide molds 43 and 43. Even in such an embodiment, according to the mold 4, generation of a step or a burr can be reliably prevented at the end including the first end surface of the tubular molded body 3, and the dimensional accuracy can be improved.

The specific application field in which the tubular molded body is used is not particularly limited, and can be widely applied to a field in which a connector member made of a synthetic resin is applicable, and a field in which a resin tube is inserted and connected. For example, the tubular molded body of the present invention can be used for a pipeline block such as a hydraulic circuit, a refrigerant pipe, a cooling water circulation system, a pressure transmission system, and a flow rate adjustment valve. Furthermore, not only circuit pipelines that transmit hydraulic pressure such as hydraulic pressure and water pressure, but also various pressure transmission circuit pipelines, such as circuit pipelines that transmit gas pressure such as air pressure, are formed by tubular molded bodies. Can be linked.

The mold of the present invention can produce a tubular molded body that can be used, for example, for connecting pipes provided in a pipe block with high accuracy, and has high industrial utility value.

DESCRIPTION OF SYMBOLS 1 Tubular molded object 11 Groove part 12 1st end surface 13 2nd end surface 14 Cylindrical outer peripheral surface 15 Inner peripheral surface 16 Gate trace 2 Mold 21 Fixed side mold 22 Moving side mold 23 Slide mold 24 Core mold 25 Locking block 3 Tubular molded body 31 Groove portion 32 First end surface 33 Second end surface 35 Inner peripheral surface 36 Gate mark 4 Mold 41 Fixed side mold 42 Moving side mold 43 Slide mold 44 Core mold

Claims (3)

A mold for forming a hollow tubular molded body by injection molding of a synthetic resin,
A fixed-side mold that defines at least the shape of the first end face that is one end face of the tubular molded body;
A moving-side mold that at least defines the shape of the second end face that is the other end face of the tubular molded body;
It is arranged between the fixed side mold and the moving side mold to define the shape of a part of the cylindrical outer peripheral surface of the tubular molded body, and in a direction crossing the mold opening direction as the mold is opened and closed A slide mold made movable,
A core mold that defines the shape of the inner peripheral surface of the tubular molded body,
The tubular molded body has at least one ring-shaped groove on the cylindrical outer peripheral surface,
The slide mold defines at least the shape of the groove on the cylindrical outer peripheral surface,
The fixed mold defines the shape of the cylindrical outer peripheral surface in the region closer to the first end surface than the groove closest to the first end surface,
The disk gate was configured with the end face of the core mold facing the resin inlet of the fixed mold.
Mold for tubular molded bodies. Two or more ring-shaped grooves are formed,
2. The mold for a tubular molded body according to claim 1, wherein the moving-side mold defines the shape of the cylindrical outer peripheral surface in a region closer to the second end surface than the groove portion closest to the second end surface. A tubular molded body, which is injection-molded using the mold for tubular molded bodies according to claim 1 or 2.

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