JP6109731B2 - Injection molding machine - Google Patents

Description

  The present invention relates to an injection molding machine.

  A three-platen type injection molding machine having a movable platen to which a movable mold is attached, a fixed platen to which a fixed mold is attached, and a rear platen connected to the fixed platen via a tie bar is known (see, for example, Patent Document 1). ). A movable platen is disposed between the fixed platen and the rear platen, and the movable platen and the rear platen are connected via a toggle mechanism. By driving the mold clamping motor to operate the toggle mechanism, the movable platen is moved forward and backward with respect to the fixed platen, and mold closing, mold clamping, and mold opening are performed. A cavity space is formed between the movable mold and the fixed mold in the clamped state, and the cavity space is filled with a liquid molding material. The filled molding material is solidified and extruded as a molded product after opening the mold.

JP 2004-249637 A

  Conventionally, since the toggle mechanism presses the end of the movable platen during mold clamping, the movable platen is bent, and a uniform mold clamping force cannot be obtained.

  This invention is made | formed in view of the said subject, Comprising: It aims at provision of the injection molding machine from which uniform mold-clamping force is obtained.

In order to solve the above problems, according to one aspect of the present invention,
A tie barless type injection molding machine having a fixed platen to which a fixed mold is attached, a movable platen to which a movable mold is attached, and an ejector device for ejecting a molded product,
At least one of the fixed platen and the movable platen has a mold attachment part, a platen main body facing the mold attachment part, and a mold thickness adjusting part for adjusting the position of the mold attachment part with respect to the platen main body,
The mold thickness adjusting part has a connecting part for connecting the mold attaching part and the platen main body so as to be relatively movable in a mold opening and closing direction,
The connection portion is provided with an injection molding machine in which at least a part of the ejector device is accommodated.

  According to one aspect of the present invention, an injection molding machine that provides a uniform clamping force is provided.

It is a figure which shows the state at the time of mold opening completion of the injection molding machine by one Embodiment of this invention. It is a figure which shows the state at the time of the completion | finish of mold closing of the injection molding machine by one Embodiment of this invention. It is a figure which shows the state at the time of the mold clamping completion of the injection molding machine by one Embodiment of this invention. It is a figure which shows the state at the time of metal mold | die replacement | exchange of the injection molding machine by one Embodiment of this invention. It is sectional drawing of the movable platen shown in FIG. 1, and the ejector apparatus attached to a movable platen.

  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. In addition, it is assumed that the moving direction of the movable platen when the mold is closed is the front, and the moving direction of the movable platen when the mold is opened is the rear.

  FIG. 1 is a view showing a state at the completion of mold opening of an injection molding machine according to an embodiment of the present invention. FIG. 2 is a view showing a state at the completion of mold closing of the injection molding machine according to the embodiment of the present invention. FIG. 3 is a view showing a state when mold clamping is completed in the injection molding machine according to the embodiment of the present invention. FIG. 4 is a diagram showing a state when the mold is changed in the injection molding machine according to the embodiment of the present invention. 1 to 4, a part of the frame 11 is cut away.

  The injection molding machine 10 is a two platen type, tie barless type. The injection molding machine 10 includes a frame 11, a fixed platen 12, a movable platen 13, a short link 21, a long link 22, a push rod 23, a mold clamping motor 31, a first link lock mechanism 60, a platen lock mechanism 70, and an ejector device 80. (See FIG. 5).

  The fixed platen 12 is fixed to the frame 11. A fixed mold 14 is attached to a surface of the fixed platen 12 facing the movable platen 13.

  The movable platen 13 is movable along a main guide 17 laid on the frame 11, and is movable forward and backward with respect to the fixed platen 12. A movable mold 15 is attached to a surface of the movable platen 13 facing the fixed platen 12.

  By moving the movable platen 13 back and forth with respect to the fixed platen 12, mold closing, mold clamping, and mold opening are performed. The fixed mold 14 and the movable mold 15 constitute a mold apparatus 16.

  The short link 21 is connected to the stationary platen 12 via the stationary side pin 24, and is rotatable about the stationary side pin 24 with respect to the stationary platen 12. The short link 21 is connected to a long link 22 longer than the short link 21 via a link pin 26. The short link 21 and the long link 22 are relatively rotatable around the link pin 26.

  The long link 22 includes, for example, a first link 22a and a second link 22b. The first link 22 a and the second link 22 b are connected via a connecting pin 27 and are relatively rotatable about the connecting pin 27.

  The first link 22 a is connected to the short link 21 via the link pin 26 and is rotatable relative to the short link 21 around the link pin 26. The first link 22a may be longer than the short link 21.

  The second link 22 b is connected to the movable platen 13 via the movable side pin 25, and is rotatable about the movable side pin 25 with respect to the movable platen 13. The second link 22b may have the same length as the short link 21. The second link 22b may be provided with a protrusion 22c perpendicular to the longitudinal direction of the second link 22b.

  The arrangement of the short links 21 and the long links 22 may be reversed. That is, the short link 21 may be connected to the movable platen 13 via the movable side pin 25, and the long link 22 may be connected to the fixed platen 12 via the fixed side pin 24.

  The push rod 23 is rotatable about the link pin 26 with respect to each of the short link 21 and the long link 22. Further, the push rod 23 is connected to the slider 32 via the slider pin 34 and is rotatable about the slider pin 34 with respect to the slider 32. The push rod 23 may have the same length as the short link 21.

  The mold clamping motor 31 includes a ball screw mechanism as a motion conversion unit that converts a rotational motion into a linear motion, and moves the slider 32 forward and backward along a slider guide 33 laid on the frame 11. Are relatively rotated around the link pin 26.

  In place of the mold clamping motor 31, a fluid pressure cylinder such as a hydraulic cylinder can be used. One end of the fluid pressure cylinder holds the link pin 26, and the other end of the fluid pressure cylinder holds the cylinder pin. The fluid pressure cylinder is rotatable about the link pin 26 with respect to each of the short link 21 and the long link 22 and is rotatable about the cylinder pin with respect to the frame. By extending and contracting the fluid pressure cylinder, the short link 21 and the long link 22 can be relatively rotated about the link pin 26.

  The first link lock mechanism 60 includes a locking portion 63 that is movable between a lock position that restricts the rotation of the second link 22b relative to the movable platen 13 and a lock release position that releases the restriction. The moving direction of the locking portion 63 is, for example, a direction perpendicular to the paper surface in the figure. When the locking portion 63 is moved from the unlocked position to the locked position, the inclined surface 63a (see FIG. 4) of the locking portion 63 pushes up the protrusion 22c, and the second link 22b is pressed against the stopper portion 41b. The stopper portion 41 b is formed on the movable platen 13 and can restrict the rotation of the second link 22 b with respect to the movable platen 13. On the other hand, when the latching portion 63 is moved from the lock position to the lock release position, the latching portion 63 retracts from the rotation path of the second link 22b. Thereby, the rotation of the second link 22b with respect to the movable platen 13 is allowed.

  The first link lock mechanism 60 may be in a locked state that restricts the rotation of the second link 22b relative to the movable platen 13 during injection molding, and may be unlocked when the mold is replaced. As shown in FIG. 3, the long link 22 and the short link 21 overlap in a straight line when viewed from the side when the mold is clamped, and the generation of a rotational moment can be suppressed. Further, as shown in FIG. 4, the first link 22 a can be retracted below the mold device 16 when the mold is replaced, and another mold device can be inserted between the movable platen 13 and the fixed platen 12 from the side. . This saves you the trouble of hanging the mold device with a crane and makes it possible to change the mold in a short time.

  The platen lock mechanism 70 can be switched between a locked state that restricts the movement of the movable platen 13 relative to the fixed platen 12 and an unlocked state that releases the restriction. The platen lock mechanism 70 is provided, for example, on the movable platen 13 and includes a guide clamper that clamps the main guide 17.

  The platen lock mechanism 70 may be unlocked at the time of injection molding, and may be locked at the time of mold replacement. The movable platen 13 can be moved back and forth during injection molding, and mold closing, mold clamping, and mold opening can be performed. In addition, when the mold is exchanged, the first link 22 a can be retracted below the mold apparatus 16 while the distance between the movable platen 13 and the fixed platen 12 remains constant. The distance between the fixed platen 12 and the movable platen 13 is minimized, the moving time of the movable platen 13 is short, and the die replacement is short.

  Next, the operation at the time of injection molding of the injection molding machine 10 having the above configuration will be described with reference to FIGS. At the time of injection molding, the first link lock mechanism 60 is locked, and the platen lock mechanism 70 is unlocked.

  When the mold clamping motor 31 is driven to advance the slider 32 in the state where the mold opening is completed as shown in FIG. 1, the short link 21 rotates around the fixed pin 24. At this time, the first link 22a advances while rotating about the connecting pin 27, the movable platen 13 advances, and the mold is closed. When the movable mold 15 comes into contact with the fixed mold 14, the mold closing is completed.

  When the mold closing is completed, the short link 21 and the first link 22a are in a state immediately before they overlap each other as shown in FIG. The short link 21 and the long link 22 hardly expand and contract in the longitudinal direction when the mold closing is completed, and have a natural length.

  When the mold clamping motor 31 is driven and the slider 32 is further advanced in the state where the mold closing is completed, the short link 21 and the long link 22 overlap each other as shown in FIG. The short link 21 is shorter than the natural length, and the long link 22 is longer than the natural length. A mold clamping force is generated by multiplying the driving force of the mold clamping motor 31 by the toggle magnification.

  A cavity space is formed between the fixed mold 14 and the movable mold 15 when the mold clamping is completed. The injection device fills the cavity space with a liquid molding material (for example, molten resin), and the filled molding material is solidified to form a molded product.

  Subsequently, when the mold clamping motor 31 is driven to retract the slider 32, the short link 21 rotates around the fixed pin 24. At this time, the first link 22a is retracted while rotating about the connecting pin 27, the movable platen 13 is retracted, and the mold is opened.

  After the mold opening is completed, the ejector device ejects the molded product from the mold device 16. The extruded molded product is taken out of the injection molding machine 10 by a take-out machine.

  Next, with reference to FIG. 4 etc., the operation | movement at the time of metal mold | die replacement | exchange of the injection molding machine 10 of the said structure is demonstrated. First, in a state where mold closing is completed (the state shown in FIG. 2), the first link lock mechanism 60 is switched from the locked state to the unlocked state, and the platen lock mechanism 70 is switched from the unlocked state to the locked state.

  Thereafter, when the mold clamping motor 31 moves the slider 32 backward, the short link 21 rotates around the fixed side pin 24. At this time, the second link 22b rotates around the movable pin 25, and the first link 22a retreats below the mold device 16 by gravity as shown in FIG.

  Next, the operator releases the fixation of the movable mold 15 to the movable platen 13 and releases the fixation of the fixed mold 14 to the fixed platen 12. Thereafter, the operator inserts another mold apparatus between the movable platen 13 and the fixed platen 12 from the side, and pushes out the original mold apparatus with the other mold apparatus. Subsequently, the operator fixes the inserted movable mold to the movable platen 13 and the inserted fixed mold to the fixed platen 12 with bolts or the like.

  In the present embodiment, the mold replacement is performed with the mold closed, but the mold replacement may be performed with the mold apparatus 16 slightly opened. The mold thickness adjustment described later may be performed after the mold replacement.

  FIG. 5 is a cross-sectional view showing the movable platen shown in FIG. 1 and the ejector device attached to the movable platen.

  The movable platen 13 adjusts the position of the mold attachment part 40 to which the movable mold 15 is attached, the platen body 41 facing the mold attachment part 40, and the mold attachment part 40 relative to the platen body 41 in the mold opening / closing direction. A mold thickness adjusting unit 50 is provided.

  The platen main body 41 is disposed behind the mold mounting portion 40. The platen main body 41 has a link attachment portion 41a, and the long link 22 (specifically, the second link 22b) is rotatably attached to the link attachment portion 41a via the movable side pin 25. Further, the platen main body 41 has a stopper portion 41b shown in FIG.

  The platen main body 41 is fixed to a support block 42, and the support block 42 is movable along the main guide 17. The support block 42 may be longer than the platen main body 41 in the mold opening / closing direction. The posture of the support block 42 with respect to the frame 11 is stabilized. A sub guide 46 is laid on the support block 42, and the mold mounting portion 40 is movable along the sub guide 46. The weight of the mold mounting portion 40 and the weight of the platen main body 41 act on a plurality of positions on the support block 42, and the posture of the support block 42 with respect to the frame 11 is further stabilized.

  The mold mounting portion 40 of this embodiment is guided back and forth by the sub guide 46, but may be guided back and forth by the main guide 17. It is only necessary that the mold mounting part 40 and the platen main body 41 can be relatively moved in the mold opening / closing direction. Further, the mold attaching part 40 is cantilevered from the left side in FIG. 5 by the mold thickness adjusting part 50 and may not be supported from below.

  The mold thickness adjusting unit 50 adjusts the position of the mold attaching unit 40 with respect to the platen main body 41. Depending on the thickness of the mold apparatus 16, the angle formed by the short link 21 and the long link 22 when the mold closing is completed can be adjusted to a desired angle. The mold thickness adjusting unit 50 includes a rod 51, a nut 53, and a mold thickness motor 55.

  The rod 51 connects the mold mounting portion 40 and the platen main body 41 so as to be relatively movable in the mold opening / closing direction. The rod 51 corresponds to the connecting portion described in the claims.

  For example, the rod 51 is fixed to the mold attachment portion 40 and is inserted through the through hole of the platen main body 41. A thread groove is formed on the outer periphery of the rod 51, and a nut 53 is screwed into the thread groove. A ball may be interposed between the thread groove and the nut 53 in order to reduce friction. The nut 53 is attached, for example, to the platen main body 41 so as to be rotatable and unmovable. By rotating the nut 53, the position of the rod 51 with respect to the platen main body 41 can be adjusted, and the position of the mold attachment portion 40 with respect to the platen main body 41 can be adjusted.

  As shown in FIG. 5, the nut 53 may be attached to a surface (front end surface) of the platen main body 41 that faces the mold attachment portion 40. The nut 53 may be attached to the surface (rear end surface) on the opposite side of the mold attaching portion 40 of the platen main body 41. Since the nut 53 is not provided between the mold attachment portion 40 and the platen main body 41, the interval between the mold attachment portion 40 and the platen main body 41 can be further narrowed, and the adjustment width can be increased.

  The mold thickness motor 55 is fixed to the platen main body 41. The gear 56 of the mold thickness motor 55 meshes with a gear formed on the outer periphery of the nut 53. When the mold thickness motor 55 is driven, the nut 53 is rotated, and the position of the mold attachment portion 40 with respect to the platen main body 41 can be adjusted. The mold thickness motor 55 may be connected to the nut 53 via a belt or a pulley. The nut 53 may have a sleeve shape. Strength can be secured.

  In the present embodiment, the rod 51 is fixed to the mold attaching portion 40 and the nut 53 is attached to the platen main body 41 so as to be rotatable and unmovable. However, the arrangement of the rod 51 and the nut 53 is not particularly limited. What is necessary is just to be able to adjust the position of the mold attachment part 40 with respect to the platen main body 41.

  For example, the rod 51 may be fixed to the platen main body 41, and the nut 53 may be attached to the mold attachment portion 40 so as to be rotatable and unmovable. By rotating the nut 53, the position of the mold mounting portion 40 with respect to the rod 51 can be adjusted.

  Further, the rod 51 may be attached to the mold attachment portion 40 so as to be rotatable and unmovable, and the nut 53 may be fixed to the platen main body 41. By rotating the rod 51, the position of the platen body 41 with respect to the rod 51 can be adjusted.

  Further, the rod 51 may be attached to the platen main body 41 so as to be rotatable and unmovable, and the nut 53 may be fixed to the mold attaching portion 40. By rotating the rod 51, the position of the mold attachment portion 40 relative to the rod 51 can be adjusted.

  Depending on the arrangement of the rod 51 and the nut 53, the mold thickness motor 55 may be fixed to either the mold mounting portion 40 or the platen main body 41.

  The ejector device 80 is attached to, for example, the movable platen 13 and ejects a molded product from the movable mold 15. The ejector device 80 includes a base 81, an ejector motor 82, a ball screw nut 83, a ball screw shaft 84, a holder 85, a holder guide 86, and an ejector rod 87.

  The base 81 is fixed to the rod 51. When the rod 51 is rotated at the time of mold thickness adjustment, the base 81 may be fixed to the mold mounting portion 40.

  An ejector motor 82 and a ball screw nut 83 are fixed to the base 81. A ball screw shaft 84 is screwed onto the ball screw nut 83.

  The ball screw shaft 84 can move forward and backward with respect to the output shaft of the ejector motor 82 and rotates together with the output shaft. When the output shaft is rotated, since the ball screw nut 83 is fixed, the ball screw shaft 84 is advanced and retracted while rotating.

  The holder 85 holds a bearing 89 that rotatably supports the ball screw shaft 84. When the ball screw shaft 84 is advanced and retracted while rotating, the holder 85 is advanced and retracted along the holder guide 86. The holder guide 86 can prevent the holder 85 from rotating. The holder guide 86 may be fixed to the base 81. Note that the holder guide 86 may be fixed to the mold mounting portion 40.

  The ejector rod 87 is inserted into the through hole of the mold mounting portion 40 and advances and retreats together with the holder 85.

  By driving the ejector motor 82 and moving the ball screw shaft 84 forward while rotating, the holder 85 advances, and the ejector rod 87 protrudes forward from the mold mounting portion 40. Thereby, a molded product is protruded from the movable mold 15. Thereafter, the ejector motor 82 is driven to retract the ball screw shaft 84 while rotating, whereby the holder 85 retracts and the ejector rod 87 retracts to its original position.

  Note that the ball screw nut 83 and the ball screw shaft 84 of the present embodiment convert the rotational motion of the ejector motor 82 into rotational linear motion, but they may be converted into linear motion. For example, the ball screw nut 83 may be fixed to the holder 85, and the ball screw shaft 84 may be integrated with the output shaft of the ejector motor 82. When the output shaft is rotated, the ball screw shaft 84 is rotated, the ball screw nut 83 is advanced and retracted, and the holder 85 can be advanced and retracted.

  The ejector device 80 of the present embodiment is an electric type, but may be a hydraulic type or a hybrid type, and may have a hydraulic cylinder instead of the ejector motor 82 or in addition to the ejector motor 82. Further, the ejector device 80 may have a toggle mechanism that amplifies the propulsive force by the ejector motor 82, and the configuration of the ejector device 80 is not particularly limited.

  By the way, the ejector device 80 is attached to the central portion of the movable platen 13 because the molded product protrudes from the movable mold 15.

  The rod 51 accommodates at least a part of the ejector device 80 therein. Therefore, the rod 51 is fixed to the central portion of the mold attachment portion 40, and the rod 51 presses the central portion of the mold attachment portion 40 during mold clamping. Since the movable mold 15 is attached to the central portion of the mold attachment portion 40, the uniformity of the clamping force acting between the movable mold 15 and the fixed mold 14 is good.

  The rod 51 may be cylindrical. As shown in FIG. 5, for example, a part of an ejector rod 87, a part of a ball screw shaft 84, a holder 85, a holder guide 86, and the like are accommodated in the rod 51.

  The embodiments of the injection molding machine have been described above, but the present invention is not limited to the above embodiments and the like, and various modifications are possible within the scope of the gist of the present invention described in the claims. Improvements are possible.

  For example, the ejector device 80 of the above embodiment is attached to the movable platen 13, but may be attached to the fixed platen 12. In this case, the fixed platen 12 has a mold attaching part, a platen main body disposed in front of the mold attaching part, and a mold thickness adjusting part for adjusting the position of the mold attaching part with respect to the platen main body. You can do it. The mold thickness adjusting part has a rod as a connecting part for connecting the mold attaching part and the platen main body so as to be relatively movable in the mold opening / closing direction, and the rod accommodates at least a part of the ejector device inside. . During mold clamping, the rod presses the center of the mold mounting part. Since the fixed mold 14 is attached to the central part of the mold attaching portion, the uniformity of the clamping force acting between the movable mold 15 and the fixed mold 14 is good. The ejector device 80 may be attached to both the fixed platen 12 and the movable platen 13.

  Moreover, although the injection molding machine of the said embodiment is a horizontal type | mold whose mold opening / closing direction is a horizontal direction, a vertical type | mold may be sufficient as a mold opening / closing direction.

  The injection molding machine of the above embodiment has a short link, a long link, a push rod, and the like as a transmission mechanism that transmits the driving force of the mold clamping motor to the movable platen, but the configuration of the transmission mechanism is not particularly limited. For example, the push rod 23 of the above embodiment is connected to each of the short link 21 and the long link 22 so as to be relatively rotatable around the link pin 26, but one of the short link 21 and the long link 22. On the other hand, the link pin 26 and the other pin may be connected so as to be relatively rotatable. Moreover, although the long link 22 of the said embodiment is comprised by the 1st link 22a and the 2nd link 22b, you may be comprised by one link. The injection molding machine may have a toggle mechanism disposed as a transmission mechanism between the movable platen and a fixed member provided behind the movable platen. For example, the injection molding machine may have a toggle mechanism disposed between the one end of the C-shaped frame and the movable platen as the transmission mechanism.

  Moreover, the injection molding machine of the said embodiment replaces with the 1st link lock mechanism 60, and is switched to the locked state which restrict | limits the relative rotation of the 1st link 22a and the 2nd link 22b, and a lock release state. A second link lock mechanism may be provided. The second link lock mechanism is locked at the time of injection molding and is unlocked at the time of mold replacement. When the mold is clamped, the long link 22 and the short link 21 overlap with each other in a side view. In addition, the first link 22 a can be retracted below the mold device 16 during mold replacement, and another mold device can be inserted between the movable platen 13 and the fixed platen 12 from the side. This saves you the trouble of hanging the mold device with a crane and makes it possible to change the mold in a short time. The injection molding machine may include both the first link lock mechanism 60 and the second link lock mechanism.

DESCRIPTION OF SYMBOLS 10 Injection molding machine 11 Frame 12 Fixed platen 13 Movable platen 14 Fixed mold 15 Movable mold 16 Mold apparatus 21 Short link 22 Long link 22a First link 22b Second link 23 Push rod 31 Clamping motor 40 Mold attachment part 41 Platen body 50 Die thickness adjusting part 51 Rod 53 Nut 55 Die thickness motor 80 Ejector device 82 Ejector motor 87 Ejector rod

Claims (3)

A tie barless type injection molding machine having a fixed platen to which a fixed mold is attached, a movable platen to which a movable mold is attached, and an ejector device for ejecting a molded product,
At least one of the fixed platen and the movable platen has a mold attachment part, a platen main body facing the mold attachment part, and a mold thickness adjusting part for adjusting the position of the mold attachment part with respect to the platen main body,
The mold thickness adjusting part has a connecting part for connecting the mold attaching part and the platen main body so as to be relatively movable in a mold opening and closing direction,
The connecting part is an injection molding machine in which at least a part of the ejector device is accommodated. The mold thickness adjusting part has a nut screwed into a thread groove formed on the outer periphery of the connecting part,
The injection molding machine according to claim 1, wherein the nut is rotatably attached to the platen main body or the mold attaching portion.   The injection molding machine according to claim 2, wherein the nut is attached to a surface of the platen main body facing the mold attaching portion.

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