JP2013184443A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an injection molding machine capable of decreasing damage of a turn table and an ejector rod.SOLUTION: An injection molding machine 10 includes a turn table 40 to which a mold 33 is installed, a support platen 13 supporting rotatably the turn table 40, and an ejector device 50 used for thrusting out of a molded product MM molded in the mold 33 from the mold 33. The ejector device 50 is rotatable together with the turn table 40.

Description

  The present invention relates to an injection molding machine.

  An injection molding machine manufactures a molded product by filling molten resin into a cavity space of a mold apparatus and solidifying the resin. The mold apparatus includes a fixed mold and a movable mold, and a cavity space is formed between the fixed mold and the movable mold when the mold is clamped. Mold closing, mold clamping, and mold opening of the mold apparatus are performed by a mold clamping apparatus.

  In order to integrally mold different kinds of resins (for example, two color resins), a mold apparatus is known that forms a cavity space for primary molding and a cavity space for secondary molding during mold clamping (for example, Patent Document 1). A pair of convex molds (core molds) having the same shape are formed on the movable mold, and a concave mold for primary molding (cavity mold) and a concave mold for secondary molding are formed on the fixed mold. . The movable mold is rotatable with the turntable. When the turntable rotates 180 ° after opening the mold, the combination of the convex and concave molds facing each other changes. The stop position of the turntable is defined by a stopper.

  In the integral molding of different types of resins, first, a resin is filled in a cavity space for primary molding, and a primary molded product is obtained by cooling and solidifying. Next, mold opening is performed, and the turntable rotates 180 °, so that the convex mold holding the primary molded product and the concave mold for secondary molding face each other. Next, the mold is closed and clamped, and the resin is filled in the cavity space for secondary molding and solidified by cooling, whereby a secondary molded product integrated with the primary molded product is obtained. The finished product in which the primary molded product and the secondary molded product are integrated is ejected from the movable mold by an ejector pin that can project from the movable mold.

  An ejector device that drives an ejector pin is attached to the back surface of a movable platen as a support platen that rotatably supports a turntable. The ejector device includes a drive source and an ejector rod that is advanced and retracted by the drive source. The ejector rod is inserted into the through hole of the turntable when the ejector pin is driven, and is extracted from the through hole of the turntable when the turntable rotates.

JP 2010-110852 A

  In an injection molding machine equipped with a conventional turntable, the turntable may be accidentally rotated without the ejector rod coming out of the through hole of the turntable. It was.

  This invention is made | formed in view of the said subject, Comprising: It aims at provision of the injection molding machine which can reduce damage to a turntable and an ejector rod.

In order to solve the above problems, an injection molding machine according to an aspect of the present invention is provided.
A turntable to which the mold can be attached;
A support platen that rotatably supports the turntable;
An ejector device used for projecting the molded product molded from the mold from the mold;
The ejector device is rotatable with the turntable.

  ADVANTAGE OF THE INVENTION According to this invention, the injection molding machine which can reduce damage to a turntable and an ejector rod is provided.

It is a figure which shows the outline of the injection molding machine by one Embodiment of this invention. It is a top view which fractures | ruptures and shows the principal part of the injection molding machine by one Embodiment. It is a top view which shows operation | movement of the principal part of the injection molding machine by one Embodiment. It is sectional drawing which shows the ejector apparatus by one Embodiment. It is a figure which shows the modification of the reinforcement part of a turntable.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In each of the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and description thereof will be omitted. Further, a description will be given assuming that the moving direction of the movable platen when performing mold closing is the front and the moving direction of the movable platen when performing mold opening is the rear. In each drawing, the X direction is a direction parallel to the mold clamping direction (mold opening / closing direction), the Y direction is a direction parallel to the direction connecting the pair of convex molds, and the Z direction is a direction parallel to the direction connecting the pair of toggle mounting portions. Represents. The X direction, the Y direction, and the Z direction are directions orthogonal to each other.

  FIG. 1 is a diagram showing an outline of an injection molding machine according to an embodiment of the present invention. In FIG. 1, a solid line indicates a closed state, and a two-dot chain line indicates a closed state.

  The injection molding machine 10 shown in FIG. 1 is a horizontal mold whose clamping direction (X direction) is a horizontal direction. The injection molding machine 10 includes a frame 11, a fixed platen 12 fixed to the frame 11, and a toggle support 15 that is movable with respect to the frame 11 at a predetermined distance between the fixed platen 12 and the frame 11. Is provided. A plurality of (for example, four) tie bars 16 are installed between the fixed platen 12 and the toggle support 15.

  The injection molding machine 10 further includes a movable platen 13 that is disposed so as to face the fixed platen 12 and that can be moved back and forth (moved in the X direction in the drawing) along the tie bar 16. The movable platen 13 is a support platen that rotatably supports the turntable 40 to which the movable mold 33 is attached. The fixed mold 32 is attached to a surface of the fixed platen 12 that faces the turntable 40. The fixed mold 32 and the movable mold 33 constitute a mold apparatus 30.

  The injection molding machine 10 includes a toggle mechanism 20 disposed between the movable platen 13 and the toggle support 15, a mold clamping motor 26 that operates the toggle mechanism 20, and a rotational movement of the mold clamping motor 26 in a linear motion. And a ball screw mechanism 25 serving as a transmission mechanism for converting to a toggle mechanism 20. The fixed platen 12, the movable platen 13, the toggle support 15, the toggle mechanism 20, the mold clamping motor 26, and the like constitute a mold clamping device.

  The toggle mechanism 20 includes a crosshead 24 that is movable back and forth in a direction parallel to the mold opening / closing direction, a second toggle lever 23 that is swingably attached to the crosshead 24, and a first that is swingably attached to the toggle support 15. A toggle lever 21 and a toggle arm 22 swingably attached to a toggle attachment portion 14 provided on the back surface of the movable platen 13 are provided. Between the first toggle lever 21 and the second toggle lever 23 and between the first toggle lever 21 and the toggle arm 22 are linked. The toggle mechanism 20 is a so-called inner volume five-node double toggle mechanism and has a vertically symmetrical configuration. Corresponding to the pair of upper and lower toggle arms 22, a pair of upper and lower toggle mounting portions 14 are provided on the back surface of the movable platen 13.

  The ball screw mechanism 25 includes, for example, a ball screw nut 25a fixed to the cross head 24 and a ball screw shaft 25b screwed to the ball screw nut 25a. The ball screw shaft 25b is rotatably supported with respect to the toggle support 15. When the output shaft of the mold clamping motor 26 rotates, the ball screw shaft 25b rotates and the ball screw nut 25a advances and retreats, so that the cross head 24 advances and retreats.

  The toggle mechanism 20 can be operated by driving the mold clamping motor 26 and advancing and retracting the cross head 24 as a driven member. In this case, when the cross head 24 is moved forward (moved in the right direction in the figure), the movable platen 13 is moved forward to perform mold closing. Then, a mold clamping force obtained by multiplying the propulsive force of the mold clamping motor 26 by the toggle magnification is generated, and the mold clamping is performed by the mold clamping force. When the cross head 24 is moved backward (moved to the left in the figure), the movable platen 13 is moved backward to perform mold opening.

  The mold clamping device of this embodiment uses the toggle mechanism 20 to generate the mold clamping force. However, without using the toggle mechanism 20, the driving force generated by the mold clamping motor 26 is directly applied to the mold clamping force. May be transmitted to the movable platen 13. Further, the propulsive force generated by the mold clamping cylinder may be directly transmitted to the movable platen 13 as a mold clamping force. Further, the mold may be opened and closed by a linear motor, and the mold may be clamped by an electromagnet, and the system of the mold clamping device is not limited.

  FIG. 2 is a top view of the main part of the injection molding machine according to the embodiment, partially broken away. FIG. 2 shows a state of mold clamping.

  In order to integrally mold different types of resins (for example, two color resins), the mold apparatus 30 forms a cavity space C1 for primary molding and a cavity space C2 for secondary molding at the time of mold clamping. The movable mold 33 is formed with a pair of convex molds (core molds) 33a and 33b having the same shape, and the fixed mold 32 is a concave mold (cavity mold) 32a for primary molding and a concave mold 32b for secondary molding. Is formed. The movable mold 33 is rotatable with the turntable 40. When the turntable 40 rotates 180 ° after opening the mold, the combination of the convex molds 33a and 33b and the concave molds 32a and 32b facing each other changes.

  The movable mold 33 is composed of a mold attachment plate 34 attached to the turntable 40, a spacer block 35, and a mold plate 36 on which convex molds 33a and 33b are formed. A space surrounded by the spacer block 35 is formed between the mold mounting plate 34 and the mold plate 36. An ejector plate 37 is accommodated in the space so as to be able to advance and retract. A plurality of ejector plates 37 are disposed corresponding to the plurality of convex molds 33a and 33b. An ejector pin 38 that protrudes forward is fixed to each ejector plate 37. The ejector pin 38 passes through the template 36. When the cavity spaces C1 and C2 are filled with resin, the front end surfaces of the ejector pins 38 face the cavity spaces C1 and C2, as shown in FIG. When the ejector plate 37 advances from this state, the tip of the ejector pin 38 projects forward from the template 36.

  FIG. 3 is a top view showing the operation of the main part of the injection molding machine according to the embodiment.

  In the integral molding of different types of resins, first, as shown in FIG. 3A, a primary molding cavity space C1 formed by a primary molding concave mold 32a and a convex mold 33a (see FIG. 2). The resin is supplied from the injection device 27 for primary molding, and the resin is cooled and solidified to obtain the primary molded product M1. The primary molded product M1 is held in a state of being held by the convex mold 33a by heat shrinkage due to cooling. Thereafter, the mold is opened, the turntable 40 and the movable mold 33 are rotated by 180 ° and inverted, and the convex mold 33a holding the primary molded product M1 and the concave mold 32b for secondary molding face each other. In this state, the mold is closed and the mold is clamped.

  Next, as shown in FIG. 3 (b), a cavity space C2 for secondary molding formed by the concave mold 32b for secondary molding and the convex mold 33a for holding the primary molded product M1 (see FIG. 2). The secondary molding product M2 integrated with the primary molding product M1 is obtained by supplying the resin from the secondary molding injection device 28 and cooling and solidifying the resin. A finished product (molded product) MM, in which the primary molded product M1 and the secondary molded product M2 are integrated, is held in a state of being held by the convex mold 33a.

  At this time, as shown in FIG. 3B, from the primary molding injection device 27 to the primary molding cavity space C1 formed by the concave mold 32a for primary molding and the remaining convex mold 33b. Resin is supplied, and the primary molded product M1 is obtained by cooling and solidifying the resin. Molding of the primary molded product M1 and molding of the secondary molded product M2 are performed substantially simultaneously.

  Finally, the mold is opened, and the finished product MM is ejected from the movable mold 33 by the ejector pins 38 that can project from the movable mold 33. The ejector pin 38 is driven by the ejector device 50. A plurality of ejector devices 50 are provided corresponding to the plurality of convex molds 33a and 33b, and are controlled independently.

  FIG. 4 is a cross-sectional view showing an ejector device of an injection molding machine according to an embodiment.

  The ejector device 50 includes a mounting plate 52 that is connected to the turntable 40 by a plurality of connecting rods 51. Mounted on the mounting plate 52 are an ejector motor 53 as a drive source, a ball screw 54 for converting the rotational motion of the output shaft 53a of the ejector motor 53 into a rotational linear motion, and a guide shaft 55 projecting forward. . The ejector device 50 further includes a bearing box 56 that can advance and retract along the guide shaft 55. The bearing box 56 converts the rotational linear motion generated by the ball screw 54 into linear motion and transmits the linear motion to the ejector rod 57. When the ejector rod 57 advances and retreats (moves in the X direction in the drawing), the ejector plate 37 disposed in the movable mold 33 advances and retracts the ejector pin 38.

  The ejector motor 53 includes a cylindrical output shaft 53a. A spline unit 58 that transmits the rotation of the output shaft 53a to the ball screw 54 is disposed in the output shaft 53a. The spline unit 58 includes a cylindrical spline nut 58a that rotates together with the output shaft 53a, and a spline shaft portion 58b that is spline engaged with the spline nut 58a. The spline shaft portion 58b is rotatable together with the spline nut 58a and is movable in the axial direction of the spline nut 58a (X direction in the drawing).

  The ball screw 54 includes a ball screw shaft portion 54a formed integrally with the spline shaft portion 58b, and a ball nut 54b screwed with the ball screw shaft portion 54a. A ball nut 54 b is fixed to the mounting plate 52. A shaft portion 59 is integrally formed at the front end of the ball screw shaft portion 54a. The shaft unit 60 includes the shaft portion 59, the ball screw shaft portion 54a, and the spline shaft portion 58b.

  The guide shaft 55 limits the rotational movement of the bearing box 56 and allows linear movement. Although the front end of the guide shaft 55 is separated from the turntable 40 in FIG. 4, it may be fixed to the turntable 40. In this case, since the ejector device 50 is fixed to the turntable 40, the connecting rod 51 becomes unnecessary.

  The bearing box 56 includes a housing 56a that is prevented from rotating by the guide shaft 55, and a bearing 56b that rotatably supports the shaft portion 59 of the shaft unit 60 in the housing 56a. A rear end of an ejector rod 57 is attached to the bearing box 56. The front end of the ejector rod 57 is connected to an ejector plate 37 disposed in the movable mold 33.

  When the ejector motor 53 is driven in the forward direction, the shaft unit 60 moves forward while rotating, and the bearing box 56 moves forward along the guide shaft 55. Accordingly, the ejector rod 57 moves forward, and the ejector plate 37 accommodated in the movable mold 33 moves forward. As a result, the ejector pin 38 protrudes forward from the movable mold 33, and the finished product MM can be released.

  When the ejector motor 53 is driven in the opposite direction, the shaft unit 59 moves backward while rotating, and the bearing box 56 moves backward along the guide shaft 55. Along with this, the ejector rod 57 moves backward, and the ejector plate 37 disposed in the movable mold 33 moves backward. Thus, the tip surface of the ejector pin 38 is flush with the parting surface of the movable mold 33.

  The ejector drive source of the present embodiment is an ejector motor 53, and the rotational motion of the ejector motor 53 is converted into a linear motion by the ball screw 54, but instead of the ejector motor 53, a hydraulic cylinder Alternatively, a fluid pressure cylinder such as a pneumatic cylinder may be used, and the type of drive source is not particularly limited.

  The ball screw 54 of the present embodiment is a system in which a ball nut 54b is fixed and the ball screw shaft portion 54a moves in the axial direction while rotating the output shaft 53a. However, the method is particularly limited. Not. For example, when the output shaft 53a rotates, the ball screw shaft portion may rotate and the ball nut may move in the axial direction. Further, when the output shaft 53a rotates, the ball nut may rotate and the ball screw shaft portion may move in the axial direction.

  Next, the relationship among the ejector device 50, the turntable 40, and the movable platen 13 will be described with reference to FIG. 2 again.

  The ejector device 50 is connected to the turntable 40 by a plurality of connecting rods 51 and is rotatable together with the turntable 40. Even if the ejector rod 57 does not come out of the through hole of the turntable 40 during the rotation of the turntable 40, the turntable 40 and the ejector 57 are not damaged. Since the ejector rod 57 may always be inserted into the through-hole of the turntable 40, the waiting time from when the ejector rod 57 starts to advance until the ejector plate 37 arranged in the movable mold 33 starts to advance is shortened. be able to. This effect is remarkable when the ejector rod 57 and the ejector plate 37 are connected.

  In addition, the ejector rod 57 and the ejector plate 37 may not be connected. In this case, the ejector plate 37 is urged rearward by a return spring or the like, and retreats by the urging force.

  The movable platen 13 includes a cylindrical portion 18 that forms a space that allows the ejector device 50 to rotate as the turntable 40 rotates. At least a part of each ejector device 50 is disposed in a space formed inside the cylindrical portion 18. An annular step portion 19 is formed on the front surface of the cylindrical portion 18.

  The turntable 40 includes a disk-shaped table main body 41 and a cylindrical portion 42 that protrudes rearward from the outer edge of the table main body 41. A mold mounting plate 34 of the movable mold 33 is attached to the table main body 41. The cylindrical portion 42 has a cylindrical shape and is formed coaxially with the center line of the mold apparatus 30. A bearing Br is interposed between the inner peripheral surface of the cylindrical tubular portion 42 and the outer peripheral surface of the annular step portion 19.

  The movable platen 13 rotatably supports a cylindrical portion 42 protruding from the outer edge of the table main body 41 instead of rotating the rotation shaft protruding from the rotation center of the table main body 41. The cylindrical part 42 has higher bending rigidity than the rotating shaft part, and is not easily deformed by clamping. Therefore, the inclination of the table main body 41 due to the weight of the mold can be reduced, and the parallelism between the movable mold 33 and the fixed mold 32 can be maintained.

  A gear 43 is fixed to the cylindrical portion 42 of the turntable 40, and a turntable motor (not shown) that rotates the gear 43 is attached to the movable platen 13. When the gear 43 is rotated by the turntable motor, the turntable 40 is rotated. Between the table main body part 41 and the cylindrical part 18 of the movable platen 13, a sliding plate 61 is provided for smooth rotation of the table main body part 41.

  A gear support portion 44 that supports the gear 43 is fixed to the tubular portion 18 of the movable platen 13 so that the gear 43 is not detached from the movable platen 13 forward. The gear support 44 prevents the turntable 40 from being detached from the movable platen 13. Sliding plates 62 and 63 are provided between the movable platen 13 and the gear 43 and between the gear 43 and the gear support portion 44 to smoothly rotate the gear 43, respectively.

  On the back surface of the movable platen 13 opposite to the turntable 40, a pair of toggle attachment portions 14 for attaching the toggle mechanism 20 is provided as shown in FIG. The end portions of the pair of toggle arms 22 are rotatably attached to the pair of toggle mounting portions 14. The thrust of the mold clamping motor 26 is amplified by the toggle mechanism 20 and transmitted from the pair of toggle mounting portions 14 to the movable platen 13. When the movable mold 33 and the fixed mold 32 come into contact with each other, the mold apparatus 30 applies a reaction force to the movable platen 13 via the turntable 40. At this time, the movable platen 13 is moved forward by a portion pressed by the pair of toggle mounting portions 14 and tends to bend slightly as shown by a two-dot chain line in FIG. Therefore, the turntable 40 supported by the movable platen 13 also tries to bend slightly.

  Therefore, as shown in FIG. 2, the turntable 40 further includes a reinforcing portion 45 that reinforces the table main body portion 41. The reinforcing portion 45 protrudes rearward from the table body portion 41, and at least a part thereof is disposed inside the cylindrical portion 18 of the movable platen 13. In this case, the total length of the injection molding machine 10 does not change even if the thickness of the reinforcing portion 45 is increased, so that the bending rigidity of the turntable 40 can be improved without increasing the size of the injection molding machine 10. .

  FIG. 5 is a cross-sectional view showing a modification of the reinforcing portion of the turntable. Fig.5 (a) is a figure when a reinforcement part is seen from back, FIG.5 (b) is BB sectional drawing of Fig.5 (a).

  The reinforcement part 145 shown in FIG. 5 constitutes a turntable in place of the reinforcement part 45 shown in FIG. The reinforcing portion 145 has a continuous thickness in a direction parallel to the mold clamping direction (X direction in the drawing) toward the center along a direction parallel to the direction connecting the pair of toggle mounting portions 14 (Z direction in the drawing). It is formed to be thicker. When the average thickness of the reinforcement part 145 is the same, the amount of bending of the turntable 40 caused by mold clamping is reduced.

  Note that the reinforcing portion may be formed such that the thickness in the X direction increases stepwise from the both ends in the Z direction toward the center. The ejector device 50 can be attached to the flat surface perpendicular to the X direction of the reinforcing portion via the connecting rod 51, and the axial direction of the ejector rod 57 can be easily set to the X direction.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and substitutions may be made within the scope of the gist of the present invention described in the claims. Is possible.

  For example, the injection molding machine 10 of the above embodiment is used for integral molding of different types of resins, but the uses of the injection molding machine may vary widely. The present invention can be applied to any injection molding machine including a turntable. For example, an injection molding machine includes two convex molds arranged at a 180 ° pitch around the rotation center line of a movable mold, and a concave mold facing one of the two convex molds, and molding a molded product. And the extrusion of the molded product may be performed simultaneously.

  In the injection molding machine 10 of the above embodiment, the mold opening / closing direction is a horizontal type, and the turntable 40 is rotatably supported by the movable platen 13, but the present invention is not limited to this. For example, the injection molding machine may be a vertical mold whose mold opening and closing direction is a vertical direction, and the turntable may be rotatably supported by a fixed platen. In this case, a fixed mold may be attached to the turntable, and a convex mold may be formed on the fixed mold. This is because the primary molded product is held in a state of being held by the convex mold.

  The movable mold 33 of the above embodiment has a plurality of convex molds (core molds) 33a and 33b. However, the plurality of convex molds (core molds) 33a and 33b are divided and attached to the turntable 40. May be.

  Moreover, although the turntable 40 of the said embodiment is rotated 180 degrees after mold opening, there is no restriction | limiting in the rotation angle. The rotation angle is determined according to the number of convex shapes, the number of concave shapes, and the like. Further, the number of convex shapes and the number of concave shapes may not be the same. For example, in the case of a combination of three convex molds arranged at a 120 ° pitch around the rotation axis of the turntable 40 and two concave molds opposed to any two of the three convex molds, molding of the primary molded product In addition, the molding of the secondary molded product and the ejection of the finished product can be performed simultaneously.

  Moreover, in the said embodiment, although the ejector pin 38 is used as a member which protrudes the finished product MM from the movable metal mold | die 33, a plate-shaped stripper plate may be used.

10 Injection Molding Machine 12 Fixed Platen 13 Movable Platen (Supporting Platen)
14 Toggle mounting portion 20 Toggle mechanism 30 Mold device 32 Fixed mold 32a Primary mold concave mold 32b Secondary mold concave mold 33 Movable mold 33a, 33b Convex mold 37 Ejector plate 38 Ejector pin 40 Turntable 41 Table body Part 42 Cylindrical part 45 Reinforcement part 50 Ejector device

Claims (5)

A turntable to which the mold can be attached;
A support platen that rotatably supports the turntable;
An ejector device used for projecting the molded product molded from the mold from the mold;
An injection molding machine, wherein the ejector device is rotatable together with the turntable.   The injection molding machine according to claim 1, wherein the ejector device is fixed to the turntable. The support platen includes a cylindrical portion that forms a space on the inside that allows rotation of the ejector device accompanying rotation of the turntable,
The turntable includes a table body portion to which the mold is attached and a reinforcement portion that reinforces the table body portion, and at least a part of the reinforcement portion is disposed inside the cylindrical portion of the support platen. The injection molding machine according to claim 1 or 2. The support platen is provided with a pair of toggle mounting portions for mounting a toggle mechanism for performing a mold clamping operation,
The reinforcing portion is formed such that the thickness in the direction parallel to the mold clamping direction increases continuously or stepwise toward the center along the direction parallel to the direction connecting the pair of toggle mounting portions. The injection molding machine according to claim 3. The turntable includes a table main body portion to which the mold is attached, and a cylindrical portion protruding from an outer edge of the table main body portion,
The injection molding machine according to any one of claims 1 to 4, wherein the support platen rotatably supports the cylindrical portion of the turntable.

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