JP5073246B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine used for vulcanization molding of rubber products such as anti-vibration rubber, and a molding material from an injection machine is made into a mold by bringing an injection nozzle of the injection machine into contact with a mold inlet. The present invention relates to an injection molding machine for injection.

Usually, when rubber products such as anti-vibration rubber are vulcanized with an injection molding machine, shortening of the vulcanization time is an important factor for improving productivity. As a general technique for shortening the vulcanization time, various techniques have been proposed and adopted as an effective method for raising the temperature of the molding material to be molded in the mold in advance. It was. In particular, the generally used method is to make the inside diameter of the nozzle of the injection machine small to form the throttle part, and to utilize the self-heating of the molding material (such as unvulcanized raw rubber) that passes through the throttle part. The temperature of the molding material can be raised in advance. As typical techniques for preheating the molding material prior to such vulcanization, those disclosed in Patent Document 1 and Patent Document 2 below have been proposed.
Japanese Patent Laying-Open No. 2000-317986 (see claim 1). Japanese Unexamined Patent Application Publication No. 2004-188825 (refer to Claim 1).

  A first conventional example of an injection molding machine disclosed in Patent Document 1 will be described with reference to FIG. What is disclosed in this Patent Document 1 is a device in which a throttle portion is formed at the tip of a nozzle of an injection machine, and has an injection channel 105 extending through the nozzle 101. One part is formed as an orifice 106 having a non-circular cross section, and the cross-sectional shape of the orifice 106 is longer in one direction, and at least at both ends in the major axis direction, the closer to the both ends, the perpendicular to the major axis. It is configured so as to form a flat shape in which the dimension in the direction to be gradually reduced. With such a configuration, the molding material passing through the nozzle 101 self-heats due to shear friction and is heated in advance prior to vulcanization, so the vulcanization time of the molding material is shortened.

  However, in the first conventional example, the molding material passes through the orifice 106 of the nozzle 101, so that the temperature of the molding material is raised in advance prior to vulcanization in the mold 140, thereby reducing the vulcanization time. Although shortening is possible, since the diameter of the orifice 106 is made small, there is a possibility that the temperature rise due to the internal heat generation of the molding material will excessively raise the temperature of the nozzle itself, which is a metal part. As a result, during the next injection standby, the previous unvulcanized molding material that has been filled in the nozzle portion is vulcanized due to the high heat of the nozzle itself, and the nozzle is clogged with the vulcanized material that has lost its fluidity. There was a risk that the subsequent injection molding could not be continued.

  In view of this, there has been proposed a second conventional example in which a diaphragm portion is arranged on the mold side as disclosed in Patent Document 2 shown in FIG. Explaining what is disclosed in Patent Document 2 will be described. Injection molding in which a nozzle 205 at the tip of an injection machine 201 abuts on a nozzle touch 210 of a mold 204 and a molding material is injected and injected from the injection machine 201 into the mold 204. In the machine, the diverter 216 is concentrically loosely fitted to the spool 211 formed between both sides of the runner 212 and the nozzle touch 210 of the mold 204, and the diverter 216 is movable in the axial direction of the spool 211, A drive unit 250 for moving the flow divider 216 is provided, and a throttle portion is formed between the spool 211 and the flow divider 216 on the mold 204 side, and ascending due to self-heating of the molding material at the throttle portion. Since the temperature is made, like the one in which the throttle portion is formed at the tip of the nozzle of the injection machine in FIG. Vulcanization molding material is vulcanized, the nozzle is clogged, no longer a possibility of falling into the injection molding Continue impossible by vulcanized material that has lost flowability.

  For this reason, what is disclosed in Patent Document 2 in FIG. 4 is that the molding material injected and injected from the vertical spool 206 is placed between the spool 211 and the diverter 216 in the mold 204. Or a plurality of horizontal runners 207 are configured so that the temperature is raised by self-heating at the constricted portions by the protrusions 210, so there is no need to restrict the flow path on the injection nozzle side, and a relatively wide nozzle diameter But it has been adopted because it is easy to manufacture.

  On the other hand, after the injection, the injection nozzle is usually raised to a position avoiding contact with a high-temperature mold to avoid the molding material for the next injection in the injection nozzle from being vulcanized. Let In addition, the re-weighing of the molding material for the next injection is performed at a position where the injection nozzle is separated from the nozzle touch 210 of the mold 204, but as described above, the injection nozzle diameter is relatively wide. For this reason, since the resistance of the molding material at the nozzle portion is small, a “nose dripping” phenomenon in which the molding material being measured leaks from the nozzle opening tends to occur. As a result, the raw rubber adhering to the tip of the nozzle reacts and cures by contact with a high-temperature mold and becomes a foreign substance. For some reason, it mixes with the normal molding material and closes the flow path of the above-mentioned throttle part, and the injection. There was a risk of causing troubles and defective vulcanized products.

  Therefore, the present invention solves the problems of such a conventional injection molding machine, and can prevent the molding material from leaking from an injection nozzle or the like retreated to a position away from the mold for reweighing or the like. The purpose is to provide a machine.

Therefore, the present invention provides an injection molding machine that injects a molding material from an injection machine into the mold by bringing the injection nozzle of the injection machine into contact with the injection port of the mold, and the nozzle is separated from at least the opening of the injection nozzle. A leakage prevention member is provided to prevent leakage of the molding material at the time , and the leakage prevention member is a check valve made of a ball member. The check valve is axially moved when the injection nozzle comes into contact with the mold. The valve member is configured to be opened by a rod member , and this is a means for solving the problem.

According to the present invention, in an injection molding machine that injects a molding material from an injection machine into a mold by bringing the injection nozzle of the injection machine into contact with an injection port of the mold, the nozzle is separated from at least the opening of the injection nozzle. A leakage prevention member is provided to prevent leakage of the molding material at the time , and the leakage prevention member is a check valve made of a ball member. The check valve is axially moved when the injection nozzle comes into contact with the mold. Since the rod member is configured to open the valve , the molding material in the injection nozzle does not leak and fall even when the injection nozzle is in a standby position away from the mold for the next injection. Prevents loss and improves the filling efficiency of the mold. Furthermore, the leaked molding material does not react and harden due to contact with the hot mold to generate foreign matter, ensuring high quality of the vulcanized product. . In addition, the leaking member can be accommodated inside the injection nozzle so that it is not exposed to the outside and the appearance is good, and it can be attached to the injection machine as an injection nozzle with a check valve structure. If only the mounting portion is shared, the structure can be easily modified to prevent leakage, and the check valve can be opened at the time of injection without using a special valve opening mechanism, thereby simplifying the configuration.

Embodiments of an injection molding machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a main part showing a first embodiment of the injection molding machine of the present invention, and FIG. 2 is a cross-sectional view of a main part showing a reference example of the injection molding machine of the present invention. As shown in FIG. 1, the basic configuration of the present invention is an injection molding in which an injection nozzle 2 of an injection machine 1 is brought into contact with an injection port 4 of a mold 3 to inject a molding material 5 from the injection machine 1 into the mold 3. In the machine, at least an opening 2H of the injection nozzle 2 is provided with a leakage preventing member 7 for preventing leakage of the molding material 5 when the nozzle 2 is separated from the mold 3 , and the leakage preventing member 7 is formed of a ball member. The check valve 7 is characterized in that the check valve 7 is configured to be opened by a rod member 10 that moves axially when the injection nozzle 2 comes into contact with the mold 3 .

  FIG. 1 is a cross-sectional view of an essential part showing a first embodiment of an injection molding machine according to the present invention. The left half is waiting for ascent and the right half is when descending. In the injector 1, the molding material 5 extruded in a molten state by a screw extruder (not shown) flows down from the pot into the injector flow path 8. At the same time, the pressure is used to raise an unillustrated injection plunger accommodated above the pot and reach the injection nozzle 2 installed at the lower end of the injector 1. A mold 3 such as a mold installed below the injection machine 1 includes a runner member 3C, an upper mold 3A, and a lower mold 3B that are sequentially stacked from above. A locating member 12 is attached to the upper surface of the substantially central portion of the runner member 3C with a mounting bolt 13. In the approximate center of the locating member, an injection port 4 for receiving the molding material 5 injected from the injection nozzle 2 and a vertical injection channel 6 are formed. The injection channel 6 is formed extending to the runner member 3C.

  The injection nozzle 2 includes a main body portion 2A that is attached to the lower attachment portion 1A of the injection machine 1 by screwing or the like, and a lid portion 2B that is screwed to the outer periphery of the lower end of the main body portion 2A. A ball member 7 constituting a check valve is loosely fitted with an anti-leakage member in the internal space of the main body 2A. An opening 2H is formed at the center of the lid 2B, and the rod member 10 is loosely fitted in the opening 2H so as to be axially movable. A flange is formed on the upper end portion of the rod member 10 and can be locked to the step portion above the opening 2H in the lid portion 2B, so that the drop from the injection nozzle 2 is prevented. In addition, a gap is formed between the outer periphery of the rod member 10 and the inner periphery of the opening 2H of the lid 2B, and the gap constitutes an injection flow path when the molding material 5 is injected.

  The upper end of the opening 2H of the lid 2B constitutes a valve seat 2C, and the ball member 7 is seated on the valve seat 2C and closes by the weight of the ball member 7 and the pressure of the molding material. At the time of injection, when the injection machine 1 is lowered and the injection nozzle 2 comes into contact with the upper surface of the locating member 12 in the mold 3, the rod member 10 loosely fitted to the lid portion 2 </ b> B of the injection nozzle 2 moves axially, thereby causing the ball member 7. Is pushed upward to open the valve, and the molding material 5 in the injection nozzle 2 flows down from the gap between the rod member 10 and the opening 2H of the lid 2B, and is injected from the injection port 4 of the locating member 3C in the mold 3 It is injected into the flow path 6.

  The injection port 4 at the upper end of the injection channel 6 has an appropriate shape for receiving the molding material from the injection nozzle 2 of the injection machine 1, for example, preferably the diameter of the opening 2H of the lid 2B in the injection nozzle 2. However, if the sealing property of the contact portion between the periphery of the opening 2H in the lid 2B and the upper surface of the locating member 12 is ensured, the diameter of the injection port 4 is the opening. It may be smaller than the diameter of 2H. Although not described in detail, an appropriate throttle portion 7 may be formed in the injection channel 6 so that the temperature can be raised by self-heating of the molding material. The lower end portion of the concave conical surface of the injection port 4 constitutes the minimum diameter portion, and as it goes downstream, the diameter may be gradually increased to form a throttle portion in the injection flow path 6. A plurality of horizontal branch flow paths 11 are formed on the joint surface between the runner part 3C and the upper mold 3A. In the example shown in the figure, the groove portion constituting the flow path is formed on the runner portion 3C side, but the groove portion may be formed on the upper surface of the upper mold 3A.

  The branch channel 11 is formed according to the number of cavities 9 formed according to the number of products to be vulcanized. In the illustrated example, two cavities 9 9A and 9B are formed, and therefore two branch channels 11A and 11B are also formed. Depending on the number of three, four or more cavities 9, three, four or more branch channels are formed. They are arranged radially in plan view. A branch portion is formed at a point where the vertical injection flow path 6 moves to the horizontal branch flow paths 11A, 11B, 11C. The cavity 9 is formed on the opposing surface of the upper mold 3A and the lower mold 3B. After the vulcanization molding, the molded product can be easily released by separating the upper mold 3A and the lower mold 3B.

  In the illustrated example, the injection port 4 is formed in the locating member 12 that can be separated from the runner member 3C, so the specification can be changed by preparing several locating members 12 having different shapes of the injection port 4. In addition to being able to respond freely, maintenance, inspection and replacement become easy. Further, since the branch channels 11A, 11B,... To the plurality of cavities 9A, 9B,... Can be formed between the runner member 3C and the upper mold 3A that are separated from each other, the runner member 3C and the upper mold The molded product remaining in the branch flow path 11 separated and exposed from 3A can be easily removed.

Thus, when the injection nozzle 2 is retreated to the upper standby position away from the mold 3 for the next injection, the ball member 7 is moved to the valve seat by the weight of the ball member 7 which is a check valve and the pressure of the molding material 5. Since the valve is seated and closed at 2C, it is effectively prevented that the molding material 5 leaks outside from the opening 2H of the injection nozzle 2 during the standby for the next injection. Therefore, when the molding material in the injection nozzle leaks and falls, there is no loss of material, insufficient filling of the mold, and there is no reaction and curing due to contact with the high-temperature mold. High quality is ensured. Moreover, the ball member 7 is housed inside the injection nozzle 2 so that the ball member 7 is not exposed to the outside and looks good, and can be attached to the injection machine 1 as an injection nozzle 2 having a check valve structure. Thus, only the mounting portion 1A for the injection machine 1 is shared, and the structural modification to prevent leakage becomes easy. Further, the ball member 7 is configured to be opened by the rod member 10 that moves axially when the injection nozzle 2 comes into contact with the mold 3, and can be opened without using a special valve opening mechanism, thereby simplifying the configuration. Is done.
< Reference example >

FIG. 2 is a cross-sectional view of an essential part showing a reference example of the injection molding machine of the present invention. In this reference example, a blocking member 15 that can block the injection nozzle 2 is installed as a leakage preventing member that prevents the molding material from leaking from the opening of the injection nozzle 2. The closing member 15 includes a vertical closing portion 16 that closes the injection nozzle 2 and a horizontal handle portion 17 that supports the closing portion 16. The upper surface of the blocking portion 16 is formed in a shape (for example, a concave cone surface) that matches a shape (for example, a convex cone surface) around the opening of the injection nozzle 2. The closing member 15 is advanced and retracted in the horizontal direction in conjunction with the vertical movement of the injection machine 1 by an appropriate advance / retreat mechanism (not shown).

The closing member 15 is preferably freely interposed between the injection nozzle 2 and the injection port 4 of the mold 3 so as to close both the injection nozzle 2 and the injection port 4 of the mold 3. That is, when the injection nozzle 2 finishes the injection and rises to a position avoiding contact with the hot mold 3 and waits for the next injection, the injection nozzle 2 and the upper surface of the locating member 12 of the mold 3 It was set as the obstruction | occlusion part 16 of the up-down dimension corresponded to the space | interval. In addition, at least the surface of the closed portion 16 of the closure member 15 constitutes a heat-insulating materials. If necessary, a sealing portion that bites into each other may be formed between the lower surface of the closing portion 16 and the upper surface of the locating member 12 in order to prevent backflow of the molding material from the mold.

Thus, since the blocking member 15 which is a leakage preventing member is formed separately from the injection nozzle 2 and seals the injection nozzle 2 from the outside, it is necessary to provide a special leakage prevention mechanism in the injection nozzle 2 itself. Therefore, the structure of the injection nozzle 2 itself is simplified, and the closing member 15 is used to close both the injection nozzle 2 and the injection port 4 of the mold 3. In the case of being able to be interposed between them, by one action of the closing operation by the closing member 15, not only the injection nozzle 2 side but also the back flow of the molding material from the injection port 4 of the mold 3 is effectively sealed. during the sealing of the closure member 15 at least the surface is constituted by a heat-insulating materials, to prevent mold 3 side of the high heat being transmitted to the injection nozzle 2 side through the closure member 15 effectively, the injection nozzle 2 The molding material for the next injection in It can be effectively prevented from being turned into. Incidentally, the closing member 15 may constitute all a thermally insulating materials.

  The embodiments of the present invention have been described above. However, within the scope of the present invention, the shape and type of the injection machine (including the shape of the pot) including the extruding part (melting and extruding form of the molding material by rotating the screw or the like) are described. Shape and form, injection plunger arrangement in the pot, injection material injection form from the injection machine with the injection plunger, injection nozzle shape in the injection machine (temperature increase of the molding material to improve fluidity) In addition to a ball member, a combination of a valve member and a valve seat via various conical surfaces can be selected as a check valve which is a leakage preventing member. In addition to the valve member and the separate member, the member may be configured integrally with the valve member, or the combination form of the main body portion and the lid portion may be selected as appropriate, such as separate or integral. About the mounting form In addition to screwing, it can also be attached by appropriate one-touch mounting or the like), type, shape of a blocking member that is a leakage preventing member (in addition to a hammer shape having a handle, an appropriate shape is adopted) Type and material and control form for its advance and retreat (linear advance / retreat by hydraulic pressure, advance / retreat by arc-like action, etc., can also be selected as appropriate for interlocking form to the vertical movement of the injection machine), shape of runner member, locate member, Appropriate types and materials (materials suitable for forming injection ports and injection flow paths can be selected), and joining and fixing forms (direct screwing, fixing with fixing screws, etc.) between them Can be selected.

It is principal part sectional drawing which shows 1st Example of the injection molding machine of this invention. It is principal part sectional drawing which shows the reference example of the injection molding machine of this invention. It is principal part sectional drawing of the 1st prior art example of an injection molding machine. It is principal part sectional drawing of the 2nd prior art example of an injection molding machine.

DESCRIPTION OF SYMBOLS 1 Injection machine 1A Attachment part 2 Injection | pouring nozzle 2A Main body part 2B Cover part 2C Valve seat 2H Opening part 3 Type 3A Upper type 3B Lower type 3C Runner member 4 Inlet 5 Molding material 6 Injection flow path 7 Leakage prevention member (ball member)
8 Injection machine flow path 9 Cavity 10 Rod member 11 Branch flow path 12 Locate member

Claims (1)

In an injection molding machine in which an injection nozzle of an injection machine is brought into contact with an injection port of a mold and a molding material from the injection machine is injected into a mold, at least an opening of the injection nozzle has a molding material when the nozzle is separated from the mold. A leakage prevention member for preventing leakage is provided , and the leakage prevention member is a check valve made of a ball member, and the check valve is opened by a rod member that moves axially when the injection nozzle contacts the mold. An injection molding machine characterized by being configured to do so .

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