JP2011073179A - Injection molding machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an injection molding machine capable of mass-producing a large-sized resin molding of high quality, without requiring labors and times for replacing a molding die, while preventing as much as possible an installation space from increasing. <P>SOLUTION: This injection molding machine 10 includes a fixed platen 20, a movable platen 30, a fixed molding die 40 attached to the fixed platen 20, a movable molding die 50 attached to the movable platen 30, a cavity 60 formed between the fixed molding die 40 and the movable molding die 50, and three injection units 70, 80, 90 for supplying a fused resin to the cavity 60. Each of the injection units 70, 80, 90 is provided in the periphery of the fixed platen 20, and hot runners 110 corresponding to the injection units 70, 80, 90 are provided in the fixed platen 20. Each of the hot runners 110 is constituted to be advanced and retreated with respect to the fixed molding die 40, and to bring a runner nozzle part in each of the hot runners 110, into contact with a runner side gate part 42 of the fixed molding die 40, by receiving a pressing force from each of the injection units 70, 80, 90. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an injection molding machine, and more particularly to an injection molding machine for multi-point injection molding.

  With respect to multi-point injection molding, for example, in an injection molding machine including one injection unit, a runner portion (flow path) in a molding die is branched toward a plurality of injection points.

  However, a molded product that requires multi-point injection molding is often a large product such as a bumper or an instrument panel in terms of vehicle parts. Therefore, in the molding method in which the flow path in the mold is branched as described above, the injection amount of the resin supplied to each injection point is not stable or greatly varied, and a molded product having a required accuracy is obtained. It was difficult. In addition, since the number of branches increases and the flow path length increases, the time required for molding becomes longer, resulting in a problem that productivity is lowered.

  As means for solving the above problem, for example, Patent Document 1 below discloses an injection molding machine for accurately molding a large resin molded product in a short time using a plurality of injection units. Specifically, runner openings are provided on the upper and vertical surfaces of the molds adjacent to each other at right angles so that the difference in the flow path lengths of the runners formed in the mold is reduced, and the injection units are added to these openings. Connect three. At this time, the injection unit is arranged to be inclined with respect to each surface. Two injection units are arranged on the upper surface so as to form an acute angle with each other, and one injection unit is arranged on the vertical surface.

  Further, in Patent Document 2 below, for the purpose of preventing an increase in installation space when arranging a plurality of injection cylinders, one of the two injection cylinders is electrically operated, and this electric cylinder is An injection molding machine provided on a side surface of a fixed mold is disclosed. Specifically, the fixed mold is attached to the fixed platen, and a hydraulic injection cylinder is disposed so that the nozzle portion comes into contact with the fixed mold through a through hole provided in the fixed platen. There is disclosed a device in which an electric injection cylinder is disposed on a side surface so as to be in contact with and movable with respect to a fixed mold. Then, the two injection cylinders are brought into contact with the nozzle touch portions provided on the respective surfaces of the fixed mold, and the nozzle touch portions are formed so as to communicate with the cavity through the sprue. Resin injected from each injection cylinder is supplied into the cavity.

JP 2009-61693 A JP 2007-75999 A

  However, as in Patent Document 1, if a plurality of injection units are to be connected to a fixed mold, the installation space for the injection unit is divided vertically above the fixed mold. This type of injection unit is very large, and if a plurality of such injection units are arranged around the fixed mold, a large increase in installation space is inevitable. In Patent Document 1, although a plurality of injection units are arranged to be inclined with respect to the upper surface and side surfaces of the fixed mold, a certain space saving is achieved, but this alone is still not sufficient. The injection molding machine described in Patent Document 2 uses an electric injection cylinder for space saving, but the electric injection cylinder is used for relatively low-capacity injection. It is not suitable for injection molding of large molded products.

  In recent years, there are many cases in which a plurality of types of molded products are molded by a single injection molding machine in response to a demand for high-mix low-volume production. For this reason, when the injection unit is directly connected to the fixed mold as in Patent Documents 1 and 2, the injection unit is disposed in the direction in which the mold is removed from the platen, or in the newly attached mold. Limited to locations that avoid direction. In particular, when taking into and out of the production line is taken into account, the mold is removed and carried out in a direction orthogonal to the clamping direction, and a new mold is carried in. In this case, in the injection molding machine disclosed in Patent Documents 1 and 2, the location of the injection unit is limited to the vertical direction of the mold. In this case, for example, it is necessary to lift the injection unit disposed on the upper surface of the fixed mold with a crane provided on the ceiling when the mold is replaced. .

  For example, a method of arranging a plurality of injection units in parallel with respect to the fixed mold is also conceivable, but in this case, the number of injection units is equal to a fixed platen for attaching the fixed mold (see Patent Document 2 above). It is necessary to provide a through hole. For this reason, the mold may be deformed due to insufficient rigidity of the fixed platen, which may lead to a mold clamping failure (molding failure).

  In view of the above circumstances, in the present specification, an injection molding machine capable of mass-producing high-quality large-sized resin molded products without the need for mold replacement while preventing an increase in installation space as much as possible. It is a technical problem to be solved by the present invention.

  The present invention has been made to solve the above problems. That is, an injection molding machine according to the present invention includes a fixed mold attached to a fixed platen, a movable mold attached to the movable platen, a cavity formed between the fixed mold and the movable mold, In an injection molding machine including a plurality of injection units for supplying molten resin to a cavity, at least a fixed mold is attached to a fixed platen in a replaceable manner, and three or more injection units are provided around the fixed platen. The fixed platen is provided with a number of hot runners corresponding to the injection unit, and each of the hot runners is configured to be able to advance and retreat with respect to the fixed mold, and receives a pressing force from the injection unit. It is characterized in that the nozzle portion of the hot runner is configured to contact the gate portion of the fixed mold.

  Thus, in the injection molding machine according to the present invention, a hot runner is usually provided in a stationary platen for attaching a stationary mold to the molding machine main body, which is provided in this type of molding machine, and the hot runner is provided through the hot runner. Since three or more injection units are arranged around the fixed platen so that the molten resin can be supplied to the cavity, the injection unit can be arranged away from the movable part of the mold and the space required for replacement. it can. Therefore, it is possible to provide three or more injection units without increasing the installation space so much as compared with the case where they are arranged around the fixed mold. As a result, it is possible to save space while allowing a large molded product to be molded at high speed and efficiency.

  In this injection molding machine, a hot runner that is movable relative to the fixed platen is disposed in the fixed platen, and the hot runner is configured to be movable back and forth with respect to the fixed mold. Thus, when the injection unit is pressed, the nozzle portion of the hot runner is brought into contact with the gate portion of the fixed mold by the pressing force, so that the molten resin injected from the plurality of injection units can be reliably supplied to the cavity. At the time of mold replacement, the hot runner nozzle can be retracted from the fixed mold by retracting the hot runner from the fixed mold. In this way, when the fixed mold is removed from the fixed platen in the direction perpendicular to the mold clamping direction, the mold is easily and quickly replaced while avoiding interference between the hot runner and the fixed mold. be able to. Therefore, it is possible to suitably perform multi-product molding on the same line by providing versatile molds that can be used. In addition, the hot runner can be nozzle-touched to the fixed mold by using a pressing force (so-called nozzle touch force) that allows the injection unit to nozzle-touch the hot runner without causing leakage of the molten resin. Therefore, a mechanism (such as a drive unit) for causing the hot runner to touch the nozzle is not necessary. Therefore, further space saving of the injection molding machine can be achieved.

  Moreover, according to said structure, since it is not necessary to provide many holes of a complicated shape in a fixed metal mold | die, mold intensity | strength is securable. Similarly, the fixed platen only needs to be provided with holes for attaching the number of hot runners corresponding to the injection unit, so that it is not necessary to provide a large hole for accommodating the injection unit as in Patent Document 2 above. The strength of the platen can be secured. Thereby, the deformation | transformation of the metal mold | die which may arise with a continuous use can be prevented, and the quality of a molded product can be maintained.

  Further, the three or more injection units are arranged so that they are close to each other at the contact position with the hot runner, and the separation distance between the units increases as the distance from the fixed platen increases along the mold clamping direction. Also good. This type of injection unit is usually provided with ancillary equipment such as a hydraulic or electric motor or cylinder for rotating the screw and a hopper for charging material. Therefore, if the injection units are arranged in parallel, there is a risk of causing interference between the units. In this regard, if the injection units are disposed by inclining the injection units (cylinder portions thereof) in directions that approach each other as they approach the hot runner as described above, the fixed platen can be made large while avoiding interference between the units. It does n’t matter. Therefore, it is possible to arrange a plurality of injection units without increasing the installation space of the entire molding machine.

  In this case, considering the influence of the pressing force on the hot runner or the fixed mold, the three or more injection units are all arranged on the same plane, and the two most separated injection units are Further, they may be arranged so as to be symmetrical with respect to a line parallel to the clamping direction of both molds (see FIG. 1). In this way, by determining the arrangement direction of three or more injection units, the direction perpendicular to the mold clamping direction of the pressing force (nozzle touch force) from the injection unit when the nozzle touches the hot runner of the injection unit Is applied to the hot runner or fixed mold evenly from the left and right sides. Therefore, even when the injection unit is inclined and arranged to save the space of the injection molding machine, it is possible to prevent the hot runner or the fixed mold from being distorted due to the pressing force. Good injection molding without molding defects can be performed.

  Further, a guide plate portion may be fixed to the hot runner that is not collinear with the injection unit, and the guide plate portion may be slidably supported along the advancing and retreating direction of the hot runner with respect to the fixed platen. (See FIG. 2). With this configuration, the hot runner is slid integrally with the guide plate portion, and the mold clamping orthogonal component of the pressing force (nozzle touch force) from the oblique direction of the injection unit is passed through the guide plate portion. It can be received by the sliding portion between the guide plate portion and the fixed platen. Therefore, deformation of the hot runner can be prevented and the molten resin can be stably supplied to the cavity.

  Further, in this case, the guide plate portion is fixed to the hot runner via a low heat transfer member having lower heat transfer than the guide plate portion, whereby the hot runner is provided with a predetermined gap between the guide plate portion and the guide plate portion. And may be integrally slidably supported. The hot runner is kept at a relatively high temperature to prevent the molten resin from cooling. However, when this heat is transmitted to the guide plate, the hot runner expands, and the sliding gap between the fixed platen and the sliding support is clogged. There is a possibility that so-called “galling” or the like that may prevent sliding is generated. The above configuration is made in view of this point, and the guide plate portion is arranged from the hot runner by disposing a contact member between the guide plate portion and the hot runner, and providing a predetermined gap therebetween. Heat transfer to can be suppressed. Therefore, the above-mentioned galling can be prevented and a smooth advance / retreat operation of the hot runner can be ensured.

  As described above, according to the present invention, an injection molding machine capable of mass-producing high-quality large-sized resin molded products without the need for mold replacement while preventing an increase in installation space as much as possible. Can be provided.

It is a principal part top view of the injection molding machine which concerns on one Embodiment of this invention. It is the horizontal sectional view which expanded a part of fixed platen which comprises the injection molding machine shown in Drawing 1, and its circumference. FIG. 3 is a horizontal sectional view for explaining an operation at the time of injection of a part of the fixed platen shown in FIG. 2 and its periphery. It is a principal part top view for demonstrating the operation | movement at the time of metal mold | die replacement | exchange of the injection molding machine shown in FIG. It is a principal part top view of the injection molding machine which concerns on other embodiment. It is a principal part horizontal sectional view of the injection molding machine which shows the modification of a hot runner. It is a principal part perspective view for demonstrating the outline | summary of the injection molding of the bumper using the injection molding machine which concerns on this invention. It is a principal part perspective view for demonstrating the outline | summary of the injection molding of the instrument panel using the injection molding machine which concerns on this invention. It is a vertical sectional view of the main part of the mold of the present injection molding machine used for instrument panel injection molding, and is a vertical sectional view of the main part for explaining the operation when the molten resin is injected into the instrument panel upper surface corresponding region of the cavity. It is. It is a vertical cross-sectional view of the main part of the mold of the present injection molding machine used for instrument panel injection molding, and is a vertical cross-sectional view of the main part for explaining the operation when the molten resin is injected into the instrument panel front face corresponding region of the cavity It is.

  Hereinafter, an embodiment of an injection molding machine according to the present invention and an injection molding using the injection molding machine will be described with reference to the drawings.

  FIG. 1 is a plan view of an essential part of an injection molding machine according to the present invention, and further shows a part thereof in cross section. As shown in this figure, an injection molding machine 10 according to the present invention includes a fixed platen 20, a movable platen 30, a fixed mold 40 attached to the fixed platen 20, and a movable mold 50 attached to the movable platen 30. A cavity 60 formed between the two molds 40 and 50 by clamping the fixed mold 40 and the movable mold 50, and a plurality of injection units 70 and 80 for injecting molten resin toward the cavity 60 … And. In this embodiment, three injection units 70, 80, and 90 are disposed. The fixed platen 20 and the movable platen 30 are connected to each other via a tie bar 100 so as to be relatively movable. The movable platen 30 is attached to the movable platen 30 by moving the movable platen 30 toward the fixed platen 20 by driving means (not shown). The movable mold 50 and the fixed mold 40 attached to the fixed platen 20 are clamped. As a result, a cavity 60 having a shape corresponding to the workpiece to be molded is formed between the molds 40 and 50 in a clamped state, and the injection units 70, 80, and 90 are disposed via the hot runner 110 described later. The molten resin injected from the liquid is supplied to the cavity 60.

The injection units 70, 80, and 90 are disposed around the stationary platen 20. Specifically, three injection units 70, 80, and 90 are disposed on the opposite side of the fixed platen 20 from the mold mounting surface 21. Among these, one injection unit (hereinafter simply referred to as the first injection unit 70) is the center in the width direction of the injection molding machine 10 (where the width direction is the horizontal direction and the direction orthogonal to the clamping direction d1). The same shall apply hereinafter) and disposed along the clamping direction d ₁ of the molds 40 and 50. Further, the remaining injection units (hereinafter simply referred to as second and third injection units 80 and 90) are arranged such that the first injection unit 70 and its center line intersect at a predetermined angle (30 degrees in FIG. 1). It is arranged. In this embodiment, these three injection units 70, 80, 90 are all arranged on the same horizontal plane, and the second and third injection units 80, 90 located on both sides in the width direction The single injection unit 70 is disposed at a position that is line-symmetric with respect to the center line. Accordingly, the moving direction d ₂ of the first injection unit 70 and the moving directions d ₃ and d _{4 of} the second and third injection units 80 and 90 are different from each other.

  Here, each of the injection units 70, 80, and 90 has a cylinder portion 71, 81, 91 with a built-in screw, a cylinder nozzle 72, 82, 92 provided at one end of the cylinder portion 71, 81, 91, and a cylinder Screw rotation drive units 73, 83, 93, screw advance drive units 74, 84, 94, and injection unit advance drive units 75, 85, 95 provided at the other ends of the portions 71, 81, 91 are mainly used. Prepare. Here, the injection unit advance drive units 75, 85, and 95 are for advancing the corresponding injection units 70, 80, and 90 to achieve nozzle touch with the hot runner 110 described later. It consists of motors and cylinders. In this embodiment, the central first injection unit 70 has a higher injection capacity (for example, injection flow rate or injection pressure) than the second and third injection units 80 and 90 located on both sides in the width direction. The one injection unit 70 is larger than the second and third injection units 80 and 90. Further, the second and third injection units 80 and 90 have the same level of injection capability, and their sizes (outer diameter dimensions) are substantially equal. Each of the injection units 70, 80, and 90 having the above-described configuration is disposed with the cylinder nozzles 72, 82, and 92 directed toward the fixed platen 20, and at the time of injection, the injection unit advance drive portions 75, 85, and 95 The cylinder nozzles 72, 82, and 92 are moved along the axial direction of the injection units 70, 80, and 90, and brought into contact with a nozzle receiving portion 115 of a hot runner 110 (described later) provided on the fixed platen 20, thereby The runner 110 can be pressed with a predetermined pressure.

As shown in FIG. 1, a plurality of holes 22 are formed in the fixed platen 20, and a hot runner 110 is inserted and disposed in each hole 22. In this embodiment, three holes 22 are formed penetratingly according to the number of injection units 70, 80..., And the hot runner 110 is fitted into all three holes 22. Further, the hot runner 110 is attached independently of the injection units 70, 80, and 90 so as to be movable relative to the fixed platen 20, and is configured to be movable forward and backward with respect to the fixed mold 40. In this embodiment, the holes 22 are all on the same horizontal plane and are formed in parallel with the mold clamping direction d ₁ of the molds 40 and 50. Therefore, any hot runner 110 inserted into each of these holes 22 is also arranged in parallel with the mold clamping direction d ₁ , and its forward / backward direction d ₅ coincides with the mold clamping direction d ₁ .

FIG. 2 is an enlarged cross-sectional view of a main part for explaining an attachment mode of the hot runner 110 corresponding to the second injection unit 80 arranged in an inclined manner. As shown in the figure, in this embodiment, the hot runner 110 corresponding to the second injection unit 80 includes a tubular gate bush 111, and a plate-like manifold disposed on the second injection unit 80 side of the gate bush 111. 112 and a sprue bush 113 disposed on the manifold 112 on the second injection unit 80 side. The hot runner 110 is attached to the stationary platen 20 with the runner nozzle portion 114 of the gate bush 111 facing the nozzle receiving portion 41 of the stationary mold 40, and is attached to the end surface of the sprue bush 113 on the second injection unit 80 side. A nozzle receiving portion 115 for receiving the cylinder nozzle 82 of the second injection unit 80 is formed. Accordingly, the second injection unit 80 is moved along the axial direction (movement direction d ₃ ), and a predetermined pressing force is applied to the nozzle receiving portion 115 of the hot runner 110, so that the hot runner 110 moves in the forward / backward direction d. ₅ moves toward the fixed mold 40 along, has become the Ran'nanozuru portion 114 (pressing the nozzle receiving portion 41) nozzle receiving portion 41 and the contact of the stationary mold 40 as. The other injection units 70 and 90 can have the same configuration as described above.

Further, a guide plate portion 120 is fixed to the hot runner 110 corresponding to the second injection unit 80 that is not on the same straight line. The guide plate portion 120 is generally plate-shaped, and the gate bush 111 of the hot runner 110 is inserted through an insertion hole 121 provided at the center thereof, and is erected on the end surface 23 of the fixed platen 20 on the second injection unit 80 side. The guide rod 24 is slidably fitted. Thereby, the guide plate part 120 is supported slidably along the standing direction of the guide rod 24 with respect to the fixed platen 20. In this embodiment, since the guide rod 24 is erected in parallel with the advance / retreat direction d _{5 of} the hot runner 110, the hot runner 110 fixed to the guide plate portion 120 extends along the advance / retreat direction d ₅ and guides. It can move integrally with the plate part 120.

In this embodiment, the guide plate portion 120 is fixed to the hot runner 110 via a low heat transfer member 130 having a lower heat transfer property than the guide plate portion 120. Specifically, as shown in FIG. 2, the low heat transfer member 130 includes a side surface on the center side in the width direction of the manifold 112 of the hot runner 110 and a guide plate portion 120 formed at a position facing the side surface in the width direction. It is arrange | positioned by the width direction clearance with a side surface. In other words, the component force of the direction perpendicular from the second injection unit 80 which is inclined a predetermined angle with respect to the mold clamping direction d ₁ in the inner clamping direction d ₁ of the pressing force the hot runner 110 receives (downward in terms of the FIG. 2) A low heat transfer member 130 is disposed in the gap in the width direction on the receiving side. Therefore, the guide plate portion 120 is fixed to the hot runner 110 via the low heat transfer member 130 while there is a predetermined gap between the hot runner 110 and the inner peripheral surface of the insertion hole 121 of the guide plate portion 120. Yes. Thereby, the hot runner 110 is slidably supported integrally without directly contacting the guide plate portion 120. The above-described configuration relating to the guide plate portion 120 can also be adopted for the third injection unit 90 and the first injection unit 70 that have the same arrangement relationship as the second injection unit 80.

Hereinafter, an example of injection molding using the injection molding machine 10 having the above configuration will be described. First, the movable platen 30 and the movable mold 50 are moved from the position indicated by the solid line in FIG. 1 to the position indicated by the alternate long and short dash line by the driving means (not shown), thereby being fixed to the movable mold 50 attached to the movable platen 30. The fixed mold 40 attached to the platen 20 is clamped. A cavity 60 having a shape corresponding to the workpiece to be molded is formed between the molds 40 and 50 in the clamped state. On the other hand, in accordance with the mold clamping operation, the three injection units 70, 80, and 90 are moved forward (fixed) along the movement directions d ₂ , d _3, and d ₄ by the injection unit advance drive units 75, 85, and 95. The cylinder nozzles 72, 82, and 92 of the injection units 70, 80, and 90 are brought into contact with the nozzle receiving portions 115 of the corresponding hot runners 110, respectively. Thereby, the pressing force from each injection unit 70, 80, 90 is transmitted to the corresponding hot runner 110. At this time, since the moving direction d ₂ of the first injection unit 70 coincides with the advancing and retracting direction d ₅ of the corresponding hot runner 110, all of the pressing force is transmitted to the hot runner 110. On the other hand, the moving directions d ₃ and d _{4 of} the second and third injection units 80 and 90 do not coincide with the advancing and retreating direction d ₅ of the corresponding hot runner 110, and the pressing force from the injection units 80 and 90 is Only the component force in the direction parallel to the mold clamping direction d ₁ is transmitted to the corresponding hot runner 110.

When the pressing force is transmitted to each hot runner 110 in this way, the hot runner 110 moves toward the fixed mold 40 along the advance / retreat direction d ₅ by the pressing force, and the runner nozzle portion 114 corresponds. The nozzle receiving part 41 of the fixed mold 40 is brought into contact with and pressed. As a result, the molten resin injected from the injection units 70, 80, and 90 passes through the flow passages in the cylinder nozzles 72, 82, and 92, the flow passage in the hot runner 110, and the flow passage in the fixed mold 40. And supplied to the cavity 60. When the case of the second injection unit 80 is illustrated in FIG. 3, the molten resin P injected from the second injection unit 80 by driving the screw rotation drive unit 83 and the screw advance drive unit 84 is converted into each component. By the above operation, the flow flows into the flow path in the hot runner 110 through the flow path in the cylinder nozzle 82, and further, the runner side gate portion 42 from the runner nozzle portion 114 through the nozzle receiving portion 41 of the fixed mold 40. Flows into. Then, molten resin is supplied to the cavity 60 from a cavity side gate portion 43 (a portion indicated by a broken line in FIG. 1) that communicates with the runner side gate portion 42 and opens to the cavity 60 side.

  By supplying the molten resin to the cavity 60 as described above, a workpiece (injection molded product) having a shape corresponding to the cavity 60 is formed. In this embodiment, since the injection molding is performed using the three injection units 70, 80, and 90, the injection flow rate of the molten resin to be borne by one injection unit is reduced, and the inside of the cavity 60 is accelerated. Can be filled. Accordingly, even a large injection molded product such as a bumper or an instrument panel can be molded in a short time.

In this embodiment, the three injection units 70, 80, and 90 are all arranged on the same horizontal plane, and the second and third injection units 80 and 90 that are located on both sides in the width direction are formed as molds. The second and third injection units 80 and 90 are arranged so as to be symmetrical with respect to the center line of the first injection unit 70 parallel to the mold clamping direction d ₁ of 40 and 50. When pressed to 110, the component force in the direction perpendicular to the clamping direction d ₁ of the pressing force acts equally on the hot runner 110 or the fixed mold 40. In other words, the sum of the component forces acting on the hot runner 110 or the fixed mold 40 is substantially zero. Therefore, it is possible to prevent the hot runner 110 or the fixed mold 40 from being distorted due to the pressing force of the injection units 80 and 90 on both sides in the width direction, and perform good injection molding without molding defects. . Further, in this embodiment, the low heat transfer member 130 is clamped orthogonally to the pressing force received by the hot runner 110 from the second and third injection units 80 and 90 in the gap between the guide plate portion 120 and the hot runner 110. Since the low heat transfer member 130 is disposed in the gap on the side receiving the component in the direction, any hot runner 110 need not be brought into contact with the guide plate portion 120 (see FIG. 2). Thereby, it can suppress that the heat | fever of molten resin is transmitted from the hot runner 110 to the guide plate part 120, and the galling to the guide rod 24 by the thermal deformation of the guide plate part 120 can be prevented.

Further, when the three injection units 70, 80, and 90 are disposed as described above, the hot runner 110 is disposed in parallel to the mold clamping direction d ₁ so that the injection molding machine 10 can be installed. Space can be further reduced.

Next, the operation | movement at the time of replacing | exchanging metal mold | die 40 * 50 of the injection molding machine 10 of the said structure is demonstrated. After the injection molding of a workpiece having a predetermined shape is performed one or more times as described above, the mold is exchanged in order to mold a workpiece having another shape with the same injection molding machine. For example, as shown in FIG. 4, when the fixed mold 40 attached to the fixed platen 20 is removed and another fixed mold 140 corresponding to a workpiece having another shape is attached, the mold replacement operation is performed according to the following procedure. Do. First, the three injection units 70, 80, 90 are moved rearward (in the direction away from the fixed mold 40) by the injection unit advance drive units 75, 85, 95, and the cylinders of the injection units 70, 80, 90 are moved. The contact state between the nozzles 72, 82, and 92 and the corresponding hot runner 110 is released. Then, for example, the hot runners 110 are moved back and forth in the advancing / retreating direction d ₅ with respect to the fixed mold 40 by driving means such as a hydraulic cylinder (not shown), so that the runner nozzle portion 114 of the hot runner 110 and the fixed mold 40 are The contact state with the nozzle receiving portion 41 is released, and the hot runner 110 is retracted rearward from the mold mounting surface 21 of the fixed platen 20.

  Thus, by retreating the injection units 70, 80, 90 and the hot runner 110 little by little, the fixed mold 40 can be removed from the fixed platen 20 while avoiding interference with the hot runner 110, and a new fixing is performed. The mold 140 can be easily attached to the stationary platen 20 (both are indicated by a one-dot chain line in FIG. 4). The retreating operation of the hot runner 110 is provided with an urging means such as a spring that constantly urges the hot runner 110 in a direction away from the fixed mold 40, and abuts on each injection unit 70, 80, 90. It may be automatically performed as the state is released. Further, when the driving means such as a hydraulic cylinder is provided as described above, the hot runner 110 is touched to the fixed mold 40 by using the pressing force (nozzle touch force) from each of the injection units 70, 80, and 90. When performing, the nozzle touch to the fixed mold 40 may be assisted by applying a force in a direction to bring the hot runner 110 close to the fixed mold 40 by the driving means.

  As mentioned above, although one Embodiment of this invention was described, the injection molding machine which concerns on this invention can take arbitrary forms within the scope of the present invention, without being limited to the form of the said illustration.

For example, for arrangement of the hot runner 110, in the above embodiment has exemplified a case of arranging in parallel all the hot runner 110 to the mold clamping direction d _1, of course, is not limited thereto. As long as the runner nozzle 114 of the hot runner 110 abuts against the nozzle receiver 41 of the fixed mold 40 by receiving a pressing force from the injection units 70, 80, and 90, with respect to the fixed mold 40. It is possible to take any form. For example, in the form of FIG. 1, the central hot runner 110 corresponding to the first injection unit 70 is continuously arranged in parallel to the mold clamping direction d ₁ , and the hot runners 110 and 110 on both sides in the width direction are inclined. It is also possible to arrange.

FIG. 5 shows an example thereof. The injection molding machine 10 shown in FIG. 5 has hot runners 110 and 110 on both sides in the width direction corresponding to the second and third injection units 80 and 90 and nozzles in the fixed mold 40. It differs from the injection molding machine 10 of the form shown in FIG. 1 in that it can be touched and is inclined with respect to the clamping direction d ₁ . When this configuration is adopted, the advancing and retracting directions d ₆ and d _{7 of} the hot runners 110 and 110 arranged in an inclined manner coincide with the moving directions d ₃ and d _{4 of} the corresponding second and third injection units 80 and 90. Therefore, the total pressing force from the second and third injection units 80 and 90 is transmitted in the direction along the forward and backward directions d ₆ and d ₇ of the hot runner 110. Therefore, in this case, it is not necessary to receive the component force of the pressing force in the direction in which the hot runner 110 is bent (deformed). For example, the guide plate part 120 or the low heat transfer member 130 shown in FIG.

  Moreover, although the case where the hot runner 110 is configured by the gate bush 111, the manifold 112, and the sprue bush 113 is illustrated in the above embodiment, it is not necessary to be limited to this. The nozzle receiving portion 115 for receiving the pressing force from the injection units 70, 80, and 90, and the runner nozzle portion 114 for nozzle touching the fixed mold 40, and from the nozzle receiving portion 115 toward the runner nozzle portion 114 As long as the flow path is formed so that the molten resin can be circulated, it is possible to adopt any form.

FIG. 6 shows an example of this. A hot runner 110 according to FIG. 6 has a cylindrical bush extension extending toward the second injection unit 80 side of the sprue bush 113 along the moving direction d ₃ of the second injection unit 80. The bush extension 116 is provided with a nozzle receiving portion 115 for receiving the cylinder nozzle 82 on the end surface on the second injection unit 80 side. With this configuration, it is possible to smoothly and reliably perform nozzle touch from the second injection unit 80 that is inclined with respect to the hot runner 110 as compared to the configuration illustrated in FIG. Of course, the same configuration can be adopted for the third injection unit 90.

Further, regarding the arrangement of the injection units 70, 80, and 90, in the above-described embodiment, they are all on the same plane (or on the same horizontal plane) and symmetrical with respect to the center line of the first injection unit 70. The second and third injection units 80 and 90 on both sides in the width direction are illustrated as being inclined with respect to the mold clamping direction d ₁ so as to be, but nothing needs to be limited to this. Absent. For example, as long as the pressing force from the second and third injection units 80 and 90 does not cause defects such as deformation in the hot runner 110 and the fixed mold 40, they may be arranged asymmetrically. That is, it is not necessary to arrange all the injection units 70, 80, and 90 on the same plane. Further, the second injection unit 80 and the third injection unit 90 may have different inclination angles with respect to the mold clamping direction d ₁ . Alternatively, if no physical interference occurs, the hot runners 110 and 110 on both sides in the width direction are inclined with respect to the central hot runner 110 as shown in FIG. The second and third injection units 80 and 90 corresponding to the above may be arranged in parallel with the hot runners 110 and 110. In this case, the moving directions d ₂ , d _3, and d ₄ of the _three injection units 70, 80, and 90 all coincide with the mold clamping direction d ₁ . In the above embodiment, the case where the second and third injection units 80 and 90 on both sides in the width direction are made smaller than the central first injection unit 70 is illustrated. The injection units may be the same size (that is, equivalent injection capacity).

  In the above embodiment, the case where the three injection units 70, 80, and 90 are disposed is illustrated, but of course, the present invention is not limited to this, and four or more injection units may be disposed. Is possible.

  Of course, other specific forms can be adopted for matters other than the above as long as the technical significance of the present invention is not lost.

  The injection molding machine according to the above description can be used for various injection moldings, and is particularly effective when injection molding a plurality of types of large-sized products. Hereinafter, the case where the injection molding machine according to the present invention is applied to the injection molding of bumpers and instrument panels, which are large-sized components of a vehicle, will be described with reference to FIGS.

FIG. 7 shows a perspective view of a main part for explaining an outline of injection molding of a vehicle bumper using the injection molding machine according to the present invention. The injection molding machine used here is the same as that shown in FIG. 1, and three hot runners 110 indicated by broken lines in FIG. 7 are attached to a stationary platen (not shown) so as to be relatively movable. Similarly, it is configured to be movable back and forth with respect to the fixed mold 240 indicated by a broken line. Also it is arranged parallel to any of the hot runner 110 also clamping direction d _1, the moving direction d ₅ coincides with the clamping direction d _1. The three injection units 70, 80, and 90 are all disposed on the same horizontal plane, and the second and third injection units 80 and 90 that are located on both sides in the width direction are both molds 240 and 250. The first injection unit 70 that is parallel to the mold clamping direction d ₁ is disposed so as to be symmetric with respect to the center line of the first injection unit 70.

  A cavity 260 formed by clamping the fixed mold 240 and the movable mold 250 has a shape similar to the bumper. In addition, a plurality of cavity-side gate portions 243 and 244 that open to the cavity 260 are provided on the cavity forming surface of the fixed mold 240. Here, a plurality of branched flow paths from the runner side gate portion 242 to the cavity side gate portions 243 and 244 are formed inside the fixed mold 240. In this illustrated example, the molten resin P injected from the first injection unit 70 flows into the fixed mold 240 via one runner side gate portion 242 and passes through three cavity side gate portions 243. It is supplied to the cavity 260. In addition, the molten resin P injected from the second and third injection units 80 and 90 flows into the fixed mold 240 through one runner side gate portion 242, and each has two cavity side gate portions 244. It is supplied to the cavity 260 via this.

  Thus, even when a large resin molded product is injection-molded, by using the injection molding machine 10 according to the present invention, when the injection units 70 and 80 are pressed, the pressing force of the hot runner 110 is reduced. The runner nozzle portion 114 is brought into contact with a gate receiving portion (not shown) of the fixed mold 240 so that the molten resin P can be supplied to the cavity 260. When the mold is exchanged, the hot runner 110 is attached to the fixed mold 240. By retracting, the runner nozzle portion 114 can be retracted from the fixed mold 240. Therefore, it is possible to easily replace the mold, and it is possible to cope with the production of a large variety of large-sized and thin-walled products such as bumpers.

  Further, by using a plurality of injection units 70, 80, and 90, branching of the flow path in the fixed mold 240 for each injection unit can be reduced (the flow path corresponding to the first injection unit 70 is branched into three). The flow path corresponding to the second and third injection units 80 and 90 is branched into two). Therefore, it is possible to stably produce a high-quality molded product by controlling the injection flow rate of the molten resin P in each cavity-side gate portion 243. Further, since the cavity 260 can be filled at a high pressure and at a high speed by the amount of branching, the molding time can be shortened and the productivity can be ensured. In addition, since the internal structure of the fixed mold 240 can be simplified, the cost can be reduced accordingly.

  FIG. 8 shows a perspective view of a main part for explaining an outline of injection molding of a vehicle instrument panel using the injection molding machine according to the present invention. The injection molding machine used here is the same as that shown in FIG. 1, and the arrangement mode of the injection units 70, 80, 90 and the corresponding hot runner 110 is the same as that in the case of injection molding of the bumper. Is omitted.

A cavity 360 formed by clamping the fixed mold 340 and the movable mold 350 has a shape according to the instrument panel. In addition, a plurality of cavity side gate portions 343 and 344 that open to the cavity 360 are provided on the cavity forming surface of the fixed die 340, and the runner side gate portion 342 to the cavity side gate are provided inside the fixed die 340. A plurality of branched channels reaching the parts 343 and 344 are formed. In this illustrated example, the cavity 360 is configured to be partitioned into a region 361 corresponding to the upper surface portion including the upper surface of the instrument panel, and a region 362 corresponding to the front surface portion located substantially below the upper surface portion. Therefore, in a state where the cavity 360 is partitioned as described above by appropriate partitioning means (details will be described later), the molten resin P ₁ injected from the first injection unit 70 passes through one runner side gate portion 342. Then, the gas flows into the fixed mold 340 and is supplied to the instrument panel upper surface corresponding region 361 of the cavity 360 through the three cavity side gate portions 343. Further, the molten resin P ₂ injected from the second and third injection units 80 and 90 flows into the fixed mold 340 through one runner side gate portion 342 and each has two cavity side gate portions. It is supplied to the instrument panel front face corresponding region 362 of the cavity 360 via the 344.

  As described above, even when the instrument panel is injection-molded, by using the injection molding machine 10 according to the present invention, it is possible to inject at high speed and easily exchange the mold. For this reason, as with the bumper, it is possible to cope with multi-product production of large molded products such as instrument panels. Further, since the internal structure of the fixed mold 340 can be simplified, the cost can be reduced accordingly.

  In the illustrated example, the first injection unit 70 in the center in the width direction is a unit having a higher injection capacity (for example, injection flow rate) than the second and third injection units 80 and 90 located on both sides in the width direction. In addition, the first injection unit 70 having a high injection capacity injects a region 361 corresponding to the instrument panel upper surface portion of the partitioned cavity 360, and the remaining second and third injection units 80 and 90 define the partitioned cavity. A region 362 corresponding to the instrument panel front surface portion of 360 is emitted. As described above, the number of injection units is set in consideration of different required qualities depending on the part of the instrument panel, and the instrument panel can be molded with high quality by setting the respective injection capacities.

That is, the upper surface of the instrument panel has a relatively large area, and the surface quality is also important because it is easily noticeable to the passengers. The upper surface of the instrument panel including this upper surface is formed by one injection unit 70 having a high injection capability. By molding, the molten resin P ₁ can be injected into the upper surface portion corresponding region 361 at high speed and high pressure. Therefore, it is possible to form a high quality instrument panel upper surface portion while preventing molding defects such as welds. On the other hand, the front portion of the instrument panel has a complicated cavity shape because it has holes and empty frame portions for mounting many parts such as instruments and audio equipment. Therefore, so as not to cause troubles such as entanglement burrs or air, and in order to spread the molten resin P ₂ in every corner, is required injected at a low speed and low pressure. In view of this point, by molding the front part of the instrument panel using two injection units 80 and 90 having a smaller injection capacity than the first injection unit 70, two pieces are injected while being injected at low speed and low pressure. The injection units 80 and 90 can cover the filling speed of the instrument panel front face corresponding region 362. Accordingly, it is possible to form a high quality instrument panel front face portion by preventing filling failure and the like.

Further, in this embodiment, the first injection unit 70 having the highest injection capability is arranged in the center in the width direction, and the second and third injection units 80 having lower injection capability than the first injection unit 70 are disposed on the left and right sides thereof.・ 90 is arranged. Therefore, if it is the metal mold | die used for the conventional injection molding machine, it will become possible to attach this to the stationary platen 20 (refer FIG. 1), and to inject with the center 1st injection unit 70. FIG. Also, with this injection molding machine, the mold can be easily replaced in a short time for the reasons described above. Therefore, the types of molds that can be injected can be greatly increased to increase its versatility. it can.

  In addition, since an injection unit with a high injection capacity (injection flow rate) tends to increase in size, the injection unit with a relatively high injection capacity (here, one) is placed at the center, and the injection capacity is relatively high. By arranging low injection units (two in this case) on both sides in the width direction, it is possible to give an excellent injection capability and versatility while preventing an increase in the installation space of the entire injection molding machine 10 as much as possible. it can.

Further, when the cavity 360 is partitioned into two regions as described above, it is possible to perform molding (so-called two-material molding) using two types of resins. For example, in the example of FIG. 8, the first molten resin P ₁ injected into the region 361 corresponding to the instrument panel upper surface portion and the second molten resin P ₂ injected into the region 362 corresponding to the instrument panel front surface portion. And are made of resins of different materials. In this case, the first molten resin P ₁ is injected by the first injection unit 70 and the second molten resin P ₂ is injected by the second and third injection units 80 and 90, respectively.

  This type of two-material molding can be easily performed by using, for example, the partitioning means shown in FIG. The partition means shown in the figure is a mechanism for injecting the instrument panel upper surface corresponding region 361 first, and then injecting the instrument panel front surface corresponding region 362, and the instrument panel upper surface portion of the cavity 360 in the movable mold 350. It is provided in a portion facing the boundary surface B (see FIG. 8) between the corresponding region 361 and the instrument panel front surface corresponding region 362. More specifically, the partition means is provided in the movable mold 350 and configured to be movable forward and backward with respect to the fixed mold 340, and is connected to the partition member 370 so that the partition member 370 can be advanced and retracted. And a hydraulic cylinder 380. The partition member 370 is advanced toward the fixed mold 340 by the hydraulic cylinder 380, and the cavity corresponding surface 371 provided on the front surface is brought into contact with the fixed mold 340, whereby the instrument panel upper surface corresponding area 361 is obtained. And the instrument panel front surface corresponding region 362 can be partitioned.

Instrument panel two-material molding in the case of having such a mechanism is performed, for example, by the following procedure. First, as shown in FIG. 9, the partition member 370 is advanced toward the fixed mold 340 by the hydraulic cylinder 380, and the cavity corresponding surface 371 is brought into contact with the fixed mold 340. By this operation, the cavity 360 is partitioned into the instrument panel upper surface part corresponding region 361 and the instrument panel front surface corresponding region 362, and then the first injection unit 70 is driven first, and the instrument panel upper surface corresponding region 361 injecting molten resin P _1. The injection from the first injection unit 70 is stopped when the first molten resin P ₁ has spread (filled) over the entire instrument panel upper surface corresponding region 361. Next, as shown in FIG. 10, the partition member 370 is retracted by the hydraulic cylinder 380, and the contact state between the cavity corresponding surface 371 and the fixed mold 340 is released. By this operation, a gap into which the second molten resin P ₂ flows is formed between the partition member 370 and the fixed mold 340, and then the second and third injection units 80 and 90 are driven to drive the instrument panel front portion. The second molten resin P ₂ is injected into the corresponding area 362. As a result, the second molten resin P ₂ reaches the region filled with the _first molten resin P ₁ through the newly formed gap, and the entire cavity 360 is entirely covered with the first and second molten resins. Filled with P ₁ and P ₂ . As a result, the instrument panel as an injection molded product having the boundary surface B is integrally molded.

As described above, in the injection molding machine according to the present invention, the instrument panel can be injection-molded using _two different types of materials (molten resins P ₁ and P ₂ ). In this case, according to the required quality of the instrument panel, for example, a high-performance resin is used for the instrument panel upper surface portion where higher molding quality is required, and the instrument panel front surface portion where the molding quality is not required as much as the instrument panel upper surface portion is relatively By using an inexpensive resin, it is possible to mold a high quality instrument panel at a low price. Moreover, the coating process can be omitted or simplified by performing injection molding using a pigment corresponding to the target color previously added to the molten resins P ₁ and P ₂ . Further, as described above, it is necessary for molding by combining the timing at which the instrument panel upper surface portion corresponding region 361 having a relatively large volume is ejected with the timing at which the instrument panel front surface corresponding region 362 having a relatively small volume is ejected. Time can be shortened.

Further, in the injection molding, in consideration of the difference in shrinkage due to the difference in the resin material, for example, the second molten resin P ₂ is injected into the instrument panel front surface corresponding region 362 and then the second molten resin P 2 is injected. _When the remaining shrinkage ratio of ₂ becomes equal to the shrinkage ratio of the first molten resin P ₁ , the partition member 370 is retracted to inject the first molten resin P ₁ into the instrument panel upper surface portion corresponding region 361. May be. Since the instrument panel upper surface portion is required to have higher surface quality and dimensional accuracy than the instrument panel front surface portion and higher rigidity from the viewpoint of collision safety, the first molten resin injected into the instrument panel upper surface portion corresponding region 361 P ₁ needs to use a high-performance resin material. However, the higher the performance of the resin, the lower the shrinkage during molding. Therefore, in the vicinity of the boundary surface B (see FIG. 10) between the corresponding regions 361 and 362, there is a possibility that distortion (deformation) or a gap due to the difference in shrinkage rate during molding may occur. Therefore, as described above, the instrument panel front surface corresponding region 362 is filled first, and the state of maintaining the state for a predetermined time in consideration of the difference in shrinkage during molding is filled. As a result, in the vicinity of the boundary surface B, distortion (deformation), displacement and gap due to the difference in shrinkage rate can be prevented as much as possible, and a high quality instrument panel can be formed.

  As described above, the two-instrument molding of the instrument panel has been described. Of course, this molding method can be applied to other injection-molded products without being limited to the instrument panel. That is, the cavity 260 shown in FIG. 7 is partitioned into a region corresponding to the central portion including the grill portion where relatively high molding quality is required and a region corresponding to the other side portions, and a region corresponding to the central portion. Can be injected by the first injection unit 70 having the highest injection capability, and areas corresponding to both sides can be injected by the remaining two second and third injection units 80 and 90. In this way, the central portion of the bumper including the grill portion, which has a relatively large volume and requires high molding quality, is molded by the first injection unit 70 having a high injection capacity, and the other two sides of the bumper are formed on the remaining second and second sides. By molding with the third injection units 80 and 90, it is possible to efficiently perform the injection molding of the bumper.

  In the above embodiment, as a specific example of the molding object, a large thin molded product such as a vehicle bumper or an instrument panel is given. Of course, other injection molded products are molded by the injection molding machine according to the present invention. Is possible. In addition, the number (type) of injection-molded products that can be handled by one injection molding machine is not limited from the viewpoint that mold replacement is easy and the installation space can be minimized.

DESCRIPTION OF SYMBOLS 10 Injection molding machine 20 Fixed platen 21 Mold mounting surface 22 Hole 24 Guide rod 30 Movable platen 40 * 140 * 240 * 340 Fixed mold 41 Nozzle receiving part 42 * 242 * 342 Runner side gate part 43 * 243 * 244 * 343 344 Cavity side gate part 50/250/350 Movable mold 60/260/360 Cavity 70 First injection unit 80 Second injection unit 90 Third injection unit 71/81/91 Cylinder part 72/82/92 Cylinder nozzle 75 85/95 Injection unit advance drive section 110 Hot runner 111 Gate bush 112 Manifold 113 Sprue bush 114 Runner nozzle section 115 Nozzle receiving section 120 Guide plate section 130 Low heat transfer member 361 Instrument panel upper surface section corresponding area 362 Instrument panel front section corresponding section Zone 370 Partition member 371 Cavity-compatible surface 380 Hydraulic cylinder B Boundary surface d ₁ Mold clamping direction d ₂ , d ₃ , d ₄ Movement direction d ₅ , d ₆ , d ₇ Advancing and retreating direction P, P ₁ , P ₂ Molten resin

Claims (4)

A fixed mold attached to the fixed platen; a movable mold attached to the movable platen; a cavity formed between the fixed mold and the movable mold; and supplying molten resin to the cavity In an injection molding machine comprising a plurality of injection units,
At least the stationary mold is attached to the stationary platen in a replaceable manner,
Three or more injection units are provided around the stationary platen,
The fixed platen is provided with a number of hot runners corresponding to the injection unit,
Each of the hot runners is configured to be movable back and forth with respect to the fixed mold, and the nozzle portion of the hot runner is brought into contact with the gate portion of the fixed mold in response to a pressing force from the injection unit. An injection molding machine characterized by being configured as described above.   The three or more injection units are all arranged on the same plane, and the two most distant injection units are symmetrical with respect to a line parallel to the clamping direction of both molds. The injection molding machine according to claim 1, wherein the injection molding machine is disposed so as to be inclined.   A guide plate portion is fixed to the hot runner that is not collinear with the injection unit, and the guide plate portion is slidably supported with respect to the fixed platen along the advancing and retreating direction of the hot runner. The injection molding machine according to claim 1 or 2.   The guide plate portion is fixed to the hot runner via a low heat transfer member having a lower heat transfer property than the guide plate portion, whereby the hot runner is provided with a predetermined gap between the guide plate portion and the guide plate portion. The injection molding machine according to claim 3, wherein the injection molding machine is integrally supported by sliding.

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