JP7260582B2 - Mold clamping device - Google Patents

Description

The present invention comprises a mold opening/closing mechanism for moving a movable platen, to which a movable mold is attached, in a mold opening/closing direction along tie bars with respect to a fixed platen, to which a fixed mold is attached, and clamping the fixed mold and the movable mold. The present invention relates to a mold clamping device having a mold clamping mechanism that

Regarding the mold clamping device, the overall length is a problem due to the installation space in the factory. Compared to the toggle type mold clamping device, which has a fixed platen, a movable platen, and a pressure receiving platen, and a toggle mechanism between the movable platen and the pressure receiving platen, it has a fixed platen, a movable platen, and a mold opening/closing mechanism and a mold clamping mechanism. It is known that a separate clamping device allows for a shorter overall length. In response to the above circumstances, Patent Document 1 proposes to further shorten the overall length of the mold clamping device by providing the ejector plate of the ejector device on the side away from the back surface of the movable platen with respect to the drive unit. .

As for the mold clamping device, the weight of the fixed platen and the movable platen is a problem. The weight of the fixed platen and movable platen is directly linked to the cost of the fixed platen and movable platen themselves. Further, the weight of the movable platen directly affects the cost of the mechanism itself for moving the movable platen and the running cost when moving the movable platen. Furthermore, especially in the case of large mold clamping equipment, the weight of the fixed platen and movable platen is directly linked to the transportation cost when moving the mold clamping equipment from the manufacturing plant to the customer's plant, and in some cases there are restrictions on the vehicles and roads that can be transported. sometimes receive. In view of the circumstances as described above, Patent Document 2 uses many rib structures to further reduce the weight of the movable platen.

JP 2007-290184 A JP-A-8-267463

However, in the ejector device of the mold clamping device of the injection molding machine disclosed in Patent Document 1, the ejector plate 45 is provided on the back side of the movable platen relative to the back face 25a, so the overall length of the mold clamping device may not be shortened so much. rice field. Further, in Patent Document 1, the portion of the movable platen through which the tie bar is inserted is slightly thicker than the central portion, but the entire portion is a solid portion, making it impossible to reduce the weight of the base plate. Furthermore, in the movable platen of the mold clamping device of Patent Document 2, since the central portion of the movable platen has a thicker plate thickness as a solid boss 20c, a special device is required when installing an ejector mechanism, etc. In some cases, the overall length of the device is long.

Other problems and novel features will become apparent from the description of the specification and the accompanying drawings.

A mold clamping device according to one embodiment includes a mold opening/closing mechanism for moving a movable platen to which a movable mold is attached with respect to a fixed platen to which a fixed mold is attached in a mold opening/closing direction along tie bars; and a mold clamping mechanism for clamping a movable mold, wherein the fixed platen or the movable platen is adjacent to an extended portion of a tie bar insertion portion through which a tie bar is inserted on the back side of the platen a connecting portion that connects the portions including the extended portion of the tie bar insertion portion and has a hollow portion therein.

The mold clamping device includes a mold opening/closing mechanism that moves a movable platen, to which a movable mold is attached, along tie bars with respect to a fixed platen, to which a fixed mold is attached, in a mold opening/closing direction; In a mold clamping device equipped with a mold clamping mechanism for clamping, the fixed platen or the movable platen has, on the back side of the platen, an extended portion of a tie bar insertion portion through which a tie bar is inserted, and an extension portion of an adjacent tie bar insertion portion. Since the parts are connected to each other and have a hollow part inside, the weight of the fixed platen or the movable platen can be reduced, the total length of the mold clamping device can be shortened, the weight of the fixed platen or the movable platen can be reduced, and the mold can be clamped. It is possible to achieve at least one of: achieving well-balanced suppression of the overall length of the device.

It is a side view of the mold clamping device of the injection molding machine of the first embodiment. It is the front view which looked at the movable board etc. of 1st Embodiment from the A direction of FIG. 1 is a perspective view of a movable platen main body of a first embodiment; FIG. FIG. 3 is a view of the movable platen, etc. of the first embodiment as seen from the arrow BB in FIG. 2; FIG. 3 is a CC arrow view of FIG. 2 of the movable platen and the like of the first embodiment; FIG. 2 is a view of the movable platen main body of the first embodiment taken along line DD of FIG. 1; It is a side view of the mold clamping device of the injection molding machine of the second embodiment.

Specific embodiments will be described in detail below with reference to the drawings. However, it is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate. In addition, there are portions where hatching is omitted so as not to complicate the drawing.
<Schematic configuration of mold clamping device>

An outline of a mold clamping device 2 of an injection molding machine 1 according to one embodiment of the present invention will be described with reference to FIG. FIG. 1 is a side view of a mold clamping device 2 of an injection molding machine 1 in a mold closed state. In the lower half, the vertical cross section of the axial center of the tie bar of the mold clamping device is shown with hidden lines and dashed lines. An injection molding machine 1 includes a mold clamping device 2 and an injection device 4 on a base 3 . The mold clamping device 2 includes two mold opening/closing mechanisms 15 for moving a movable platen 14 to which a movable mold 13 is attached with respect to a fixed platen 12 to which a fixed mold 11 is attached, and a fixed mold 11 and a movable mold 13. It has mold clamping cylinders 17 of four mold clamping mechanisms 16 for clamping molds. Note that the mold clamping mechanism 16 may use an electric motor. The injection device 4 also has a screw (not shown) inside the heating cylinder 18 and a nozzle 19 at the tip of the heating cylinder 18 .

A clamping device (not shown) is provided on the mold mounting surface 20 of the fixed platen 12 fixed on the base 3 , and the fixed mold 11 can be mounted on the mold mounting surface 20 by the clamping device. A mortar portion 22 for inserting the nozzle 19 of the injection device 4 is provided at the center of the back surface 21 of the stationary platen 12 opposite to the mold mounting surface 20. A hole to which the nozzle 19 is connected is provided in the mold 11 . Mold clamping cylinders 17 of a mold clamping mechanism 16 are provided in the vicinity of the four corners inside the stationary platen 12, respectively. A rod on the front side of the piston 23 of the mold clamping cylinder 17 constitutes a tie bar 24 . Therefore, in the present invention, tie bars 24 are attached to the fixed platen 12 . The mold clamping cylinder 17 is a reciprocating cylinder having a mold clamping side oil chamber 25 on the front side of the piston 23 and a strong mold opening side oil chamber 26 on the rear side of the piston 23 . The mold clamping cylinder 17 is also connected to a hydraulic system (not shown). A position adjusting mechanism 32 for the tie bar 24 is provided on the rear surface 21 side of the stationary platen 12, and the position of the tie bar 24 can be adjusted when the engagement groove 27 and the half nut 31 are engaged.

A plurality of engaging grooves 27 having the same pitch are formed over a predetermined length in the mold opening/closing direction at positions near the tip side of the outer periphery of each tie bar 24 . Each tie bar 24 is inserted into tie bar insertion holes 28 provided in the vicinity of the four corners of the movable platen 14 . The movable platen 14 is movable on the base 3 along tie bars 24 . The mold clamping device 2 may be provided with a tie bar holder for holding each tie bar 24 on the back surface 29 side of the movable platen 14 on the base 3 at a constant distance from the movable platen 14 .

A clamping device (not shown) is provided on the mold mounting surface 30 of the movable platen 14 , and the movable mold 13 can be mounted on the mold mounting surface 30 by the clamping device. A half nut 31 is attached near the tie bar insertion hole 28 on the rear surface 29 of the movable platen 14 opposite to the mold mounting surface 30 . The half nut 31 can be engaged with the engagement groove 27 of the tie bar 24 . The mold mounting surfaces 20 and 30 of the fixed platen 12 and the movable platen 14 may be provided with heat insulating plates as necessary when using a heating/cooling mold or a hot runner mold.

Two mold opening/closing mechanisms 15 are arranged on the base 3 to move a movable platen 14 to which a movable mold 13 is attached to approach or separate from a fixed platen 12 to which a fixed mold 11 is attached. In this embodiment, the mold opening/closing mechanism 15 is an electric mechanism, and includes a servomotor 33, a ball screw 34 of a ball screw mechanism, a ball screw nut 35, and the like. The servomotor 33 is connected to a control device (not shown). The mold opening/closing mechanism may use a hydraulic cylinder.
<Description of movable platen>

Next, the details of the movable platen 14 will be described with reference to FIGS. 2 to 6. FIG. FIG. 2 is a front view of the movable platen and the like as seen from direction A in FIG. FIG. 3 is a perspective view of a movable platen body. FIG. 4 is a view of the movable platen and the like of the first embodiment taken along the line BB in FIG. FIG. 5 is a view of the movable platen and the like of the first embodiment taken along line CC of FIG. FIG. 6 is a view of the movable platen main body of the first embodiment taken along line DD in FIG.

In this specification, the movable platen main body 39 in the movable platen 14 refers to a mass to which other members are not attached. The movable platen main body 39 is made of cast iron and is machined later for the purpose of improving surface accuracy and for the purpose of forming bolt holes, etc., and becomes the movable platen 14 by attaching other members. The movable platen main body 39 includes a mold mounting portion 40 having a mold mounting surface 30 to which the movable mold 13 is mounted, and an extension portion 41 connected to the rear side of the mold mounting portion 40 . The extension portion 41 connects the extension portions 44, 44 of the tie bar insertion portion through which the adjacent tie bars 24 are respectively inserted, or the portions including the extension portions 44, 44 of the tie bar insertion portion, and is hollow inside. and a connecting portion 46 having a portion 45 . The movable platen main body 39 is explained by giving the names of the mold mounting portion 40, the extending portion 44 of the tie bar insertion portion which is the extending portion 41, the connecting portion 46, and the like. There is no clear boundary between each part because it is integrally molded by such as.

To explain the movable platen body 39 in more detail, the mold mounting portion 40 has a mold mounting surface 30 to which the movable mold 13 is mounted. Equipped with various valves for molds. Tie bar insertion holes 28 through which the tie bars 24 are inserted are provided in the vicinity of the four corners of the mold mounting portion 40 . A portion of the mold mounting portion 40 having the tie bar insertion hole 28 is a portion 43 of the tie bar insertion portion 42 on the mold mounting surface side. (not shown) is fitted. Further, the rod hole 48 of the ejector rod 47 and the like are formed on the center side of the mold mounting portion 40 . The mold mounting portion 40 is formed with a tie bar insertion hole 28, a rod hole 48 for the ejector rod 47, a bolt hole (not shown), etc., but other portions are solid members.

An extending portion 41 is formed on the rear side of the mold mounting portion 40 of the movable platen main body 39 . As shown in the cross section of the tie bar portion on the lower half side of the movable plate main body 39 in FIG. 4 and in FIG. An extension portion 44 of the tie bar insertion portion, which is a side portion, is formed. The extending portion 44 of the tie bar inserting portion is a substantially cylindrical member having a tie bar inserting hole 28 through which the tie bar 24 is inserted at the axial center portion in the mold opening/closing direction. However, the extended portion 44 of the tie bar insertion portion is not limited to have a doughnut-shaped cross section in connection with other portions to be described later.

Further, as shown in FIGS. 5 and 6, of the extension portion 41 on the back side of the movable platen 14, from the extension portion 44 of the tie bar insertion portion toward the center O of the movable platen, the width is wider than the diameter of the tie bar 24. , a radially thick portion 49 is formed. The extended portion 44 of the tie bar insertion portion and the inner radially thick portion 49 are the mold clamping force transmission portion 36 that directly transmits the mold clamping force at the time of mold clamping to the movable mold 13 most directly. As for the length of the radial thick portion 49 in the mold opening/closing direction, the length of the portion located near the extended portion 44 of the tie bar insertion portion is equal to the length of the extended portion 44 of the tie bar insertion portion or a connecting portion described later. It has the same length as 46. However, the length of the radial thick portion 49 in the mold opening/closing direction on the side of the center O of the movable platen 14, as shown in FIGS. It is shorter than the length of the direction. This is mainly for the purpose of reducing the weight of the movable platen 14. In anticipation of the safety factor against the stress of the movable platen main body 39 at the time of mold clamping, even if the strength of the radially thick portion 49 does not increase, The plate thickness in the opening and closing direction of the mold is thin at the portion where there is no problem.

Then, among the extension portions 41 connected to the back surface of the mold mounting portion 40, the extension portions 44 of the adjacent tie bar insertion portions, or the extension portions 44 of the adjacent tie bar insertion portions and the radial thickness of other members A connecting portion 46 is formed by connecting the meat portions 49 to each other. As shown in FIGS. 2 and 6, the connecting portion 46 is formed by extending portions 44, 44 of adjacent tie bar insertion portions through which the upper two tie bars 24 are respectively inserted, or the extension portion 44 of the tie bar insertion portion. , the extended portions 44, 44 of adjacent tie bar insertion portions through which the lower two tie bars 24 are respectively inserted, or the portion including the extended portion 44 of the tie bar insertion portion The lower horizontal connecting portion 51 that connects them together, the extended portions 44, 44 of the adjacent tie bar insertion portions through which the two tie bars 24 on the operating side are respectively inserted, or the portions including the extended portion 44 of the tie bar insertion portion. The operation side vertical connection portion 52 to be connected, the extension portions 44, 44 of the tie bar insertion portion through which the two tie bars 24 on the counter operation side are respectively inserted, or the portions including the extension portions 44, 44 of the tie bar insertion portion are connected to each other. It consists of four connecting portions of the opposite operation side vertical connecting portion 53 . Therefore, the extending portions 44, 44 of the tie bar insertion portion located in the diagonal direction of the movable platen 14 (for example, the extending portions 44 of the upper tie bar insertion portion on the operation side and the lower portion on the opposite operation side) are the adjacent tie bar insertion portions. They are not connected by the connecting portions 46 , not by the extended portions 44 .

As shown in FIGS. 2 to 6, the back side of the movable platen 14 has a frame-shaped extended portion 41 protruding from the member described above. In the present invention, the frame shape is not limited to a completely quadrangular shape, and includes unevenness, curved surfaces, planes with varying angles, etc. on the outer and inner wall surfaces of the extended portion 41 . Further, as shown in FIGS. 1 and 6, a support portion 54 for placing the movable platen 14 on the base 3 is provided on the further lower surface side of the extending portions 44, 44 of the lower tie bar insertion portion. A leg portion 55 is attached to the support portion 54 to which a wheel and a ball are attached. Then, the leg portion 55 moves on the rail 56 on the base 3 .

Due to the above structure, the movable platen 14 has a relatively thin plate thickness in the mold opening/closing direction at the center side of the mold mounting portion 40 when viewed from the direction of arrow A in FIG. Since the extended portion 41 including the extended portion 44 of the tie bar insertion portion, the connecting portion 46 and the like is provided on the rear side of the mold mounting portion 40, the plate thickness in the mold opening/closing direction is increased. As shown in FIGS. 3 to 5, a concave portion 57 is formed inside the frame-shaped extended portion 41 on the back side of the movable platen 14 . Inside the concave portion 57, block-shaped thick portions protruding from the rear surface 59 of the mold mounting portion 40 among the radial direction thick portions 49 are provided on the four corner sides of the extension portions 44 of the respective tie bar insertion portions. 58 are formed. The thick portion 58 is a portion that overlaps with a portion of the movable mold 13 attached to the movable platen 14 when projected from the direction of arrow A in FIG. Therefore, as shown in FIG. 5, most of the reaction force from the movable mold 13 at the time of mold clamping is not the thin portion 60 of the mold mounting portion 40, but the radial thickness connected to the mold mounting portion 40. The power is transmitted to the entire frame-shaped extended portion 41 including the connecting portion 46 via the thick portion 58 of the thick portion 49 . 2 other than the thick portion 58 of the back surface 59 of the mold mounting portion 40 corresponding to the bottom portion of the recess 57 is a thin portion 60 having a thinner plate thickness. A rod hole 48 for the ejector rod 47 is formed in the thin portion 60 . In the first embodiment, the thick portion 58 is drawn solid, but a plurality or a single elongated hole or circular hole may be provided from the back side toward the mold mounting surface 30 side to further reduce the weight. may In this case, the depth of the hole is desirably as deep as the back surface 59 of the thin portion 60 of the mold mounting portion 40 or slightly shallower than that.

The connecting portion 46 will be further described with reference to FIGS. 3 to 6. FIG. Although the respective connecting portions 46 are slightly different in shape, they are functionally the same, so the upper horizontal connecting portion 50 will be described. The upper horizontal connecting portion 50 includes an outer connecting portion 61 that connects the extended portions 44 of the tie bar insertion portion, and an inner connection portion that connects the radially thick portions 49 that include the extended portions 44 of the tie bar insertion portion. 62, with a cavity 45 between them for weight reduction. Although one hollow portion 45 is formed in the first embodiment, a plurality of hollow portions 45 may be provided, or a rib or column connecting the outer connecting portion 61 and the inner connecting portion 62 may be provided inside the hollow portion 45. may be provided. The outer connecting portion 61 and the inner connecting portion 62 of the connecting portion 46 may be connected between portions including the extending portion 44 of the tie bar insertion portion.

As shown in FIGS. 3 and 5, the outer connecting portion 61 is a portion forming the outer wall surface 38 of the outer side wall portion of the movable platen 14 . The outer connecting portion 61 is also formed with a hole portion 63 for connecting the outside world side and the hollow portion 45 for the purpose of weight reduction. Although the shape and number of the hole portions 63 are not limited, in the first embodiment, ribs 64 are formed in the mold opening/closing direction at intermediate positions between the tie bar insertion portions of the outer connecting portion 61 , and holes are formed on both sides of the ribs 64 . A portion 63 is formed. The hole 63 is also necessary to form the cavity 45 when casting the movable platen main body 39. As a result, the cavity 45 is an open cavity connected to the outside world through the hole 63. Further, in the first embodiment, the outer connecting portion 61 is connected from the inner portion of the tie bar inserting portion extending portion 44 , and a recess is provided between the tie bar inserting portion extending portion 44 and the outer wall surface 38 of the outer connecting portion 61 . A groove 65 is formed to avoid stress concentration in this area. The number and number of ribs 64 and holes 63 are not limited, and the recessed grooves 65 are not essential. Further, the outer connecting portion 61 may be in the form of a curved plate, and the thickness thereof may be uniform or non-uniform.

As shown in FIGS. 3 and 5, the inner connecting portion 62 constitutes an inner wall surface 66 of the inner wall portion of the recess 57 formed on the back side of the movable platen 14 in the mold opening/closing direction. The inner connecting portion 62 is also formed with a hole portion 67 connecting the hollow portion 45 and the concave portion 57 for the purpose of weight reduction. Although the shape and number of the holes 67 are not limited, in the first embodiment, one hole 67 is formed in the inner connecting portion 62 in the intermediate portion between the thick portions 58 . ing. Note that the number of holes 67 is not limited. In the first embodiment, the thickness of the connecting portion 46 formed by the outer connecting portion 61 and the inner connecting portion 62 (the distance between the outer wall surface 38 of the outer connecting portion 61 and the inner wall surface 66 of the inner connecting portion 62) is , is larger than the diameter of the tie bar 24 . The fact that the thickness of the connecting portion 46 is larger than the diameter of the tie bar 24 is useful for increasing the strength of the movable platen main body 39 as a box-shaped structure. It is also useful for securing a space for attaching the half nut 31. Note that the inner connecting portion 62 may be connected to the portion of the extending portions 44, 44 of the tie bar insertion portion on the side of the center O of the movable platen 14, respectively. Furthermore, the inner connecting portion 62 is not limited to a flat plate shape, and may be a curved plate shape or a bent flat plate shape. Also, the thickness of the inner connecting portion 62 may be uniform or non-uniform.

As shown in FIG. 3 and the like, a concave portion 57 is formed on the back surface 29 side of the movable platen 14 . In the first embodiment, the recess 57 is composed of the inner wall surface 66 of the inner connecting portion 62 of the frame-shaped extended portion 41, the thick portion 58 of the radially thick portion 49, and the back surface 59 of the mold mounting portion 40. be done. However, it may be composed of the inner wall surface 66 of the inner connecting portion 62 and the back surface 59 of the mold mounting portion 40 . Since the movable platen 14 has a box-shaped structure including the frame-shaped extended portion 41 and the recessed portion 57 therein, it is advantageous in terms of strength and in terms of installation space for an ejector mechanism 72, etc., which will be described later. Advantageous. Note that the concave portion 57 does not exclude those provided with ribs.

Further, as shown in FIGS. 2 and 3 , a back plate portion 68 is provided on the back side of the frame-shaped extended portion 41 . The rear plate portion 68 has a flat surface orthogonal to the mold opening/closing direction for mounting the servo motor 71 for the ejector and the half nut 31 described below. Further, in the first embodiment, the four corners on the inner peripheral side of the back plate portion 68 are curved. The inner peripheral side of the rear plate portion 68 may be on the same surface as the inner wall surface 66 of the inner connecting portion 62, or may be provided with an overhang so that the opening of the recess 57 becomes smaller. As shown in FIG. 4 and the like, tie bar insertion holes 28 are formed near the four corners of the back plate portion 68, and bushes (not shown) for guiding the tie bar 24 are inserted into the portions of the tie bar insertion holes 28 in contact with the rear side. It is

As shown in FIGS. 1 and 2, a pair of nuts having engaging teeth to be engaged with the engaging grooves 27 of the tie bars 24 are mounted on the surface of the back plate portion 68 in the vicinity of the tie bar insertion holes 28. A half nut 31 is attached to each. In the half nut 31 of this embodiment, two nuts of the half nut 31 are horizontally opened and closed by an actuator 37 such as a servo motor. Note that the structure of the half nut 31 is not limited to this. A bracket 70 for mounting an ejector servomotor is formed on the rear surface 29 of the rear plate portion 68 . When the top priority is given to shortening the overall length of the mold opening/closing direction of the mold clamping device 2, and the overall width of the mold clamping device 2 from the operating side to the non-operating side is allowed to increase, only the drive shaft and the drive pulley are required. A ejector servomotor 71 may be attached to the side surface of the movable platen 14 so as to protrude slightly from the back surface 29 to the side opposite to the mold mounting surface.

In the present invention, the rear plate portion 68 is not essential, and the rear surface 29 of the extension portion 44 of the tie bar insertion portion and the rear surface 29 of the connecting portion 46 may constitute the rear surface 29 of the frame-shaped extension portion 41 as they are. good. In that case, the back side surface of the tie bar insertion portion extending portion 44 and the back side surface of the connecting portion 46 may be different in height. That is, one of them may be raised, and the plate thickness of the movable platen main body 39 may be defined by the raised portion. Also, it is not essential to provide a half nut on the rear side surface of the tie bar insertion portion extension portion 44 of the frame-shaped extension portion 41 . That is, the half nuts may be provided on the stationary platen 12 instead of the movable platen 14 of the first embodiment. In addition, part or all of the rear side portions of the outer connecting portion 61 and the inner connecting portion 62 may be free of the rear plate. Therefore, the hollow portion 45 in the present invention also includes a concave portion.

In the movable platen 14 having the above structure, the mold mounting surface 30 of the movable platen 14 and the half nut 31 have a length E of one side of the mold mounting surface 30 of the movable platen 14 shown in FIGS. The ratio of the length F (thickness of the movable platen in the mold opening/closing direction) to the back surface 29 to be attached is large. Specifically, the ratio (E/F) obtained by dividing the side length E of the movable platen 14 by the plate thickness length F is not limited to this, but may be 35% to 50%. preferable. Furthermore, if the plate thickness of the movable platen 14 is excessively thickened, the total length of the mold clamping device 2 becomes long. The relationship between the thickness G of the thin portion 60 of the mold mounting portion 40 and the thickness F of the movable platen 14 is obtained by dividing the thickness G of the thin portion 60 of the mold mounting portion 40 by the length F of the plate thickness. Although the ratio (G/F) is not limited to this, it is preferably 8% to 40%, more preferably 10% to 25%. The ratio (I/F) of the length I of the extension portion 41 to the length F of the plate thickness of the movable platen 14 is calculated backward from the above ratio, and is preferably 60% to 92%, more preferably 75%. to 90% is more desirable.

Although the present invention is not completely limited, it is primarily directed to a mold clamping device that locks tie bars by means of half nuts. In this type of mold clamping device that locks tie bars with half nuts, the mold opening/closing direction is perpendicular to the mold opening/closing direction between the center side of the movable platen or fixed platen where the mold is mounted and the vicinity of the four corners where the half nuts are mounted. Directional distance is relatively long. The clamping force at the time of clamping and the accompanying reaction force from the mold are mutually exerted between the center side of the movable platen or fixed platen where the mold is attached and the vicinity of the four corners where the half nuts are attached. Therefore, the movable platen or fixed platen tends to flex during mold clamping. Therefore, the board structure of the present invention is particularly effective. On the other hand, the toggle type mold clamping device has a different basic structure in that a link mounting portion is provided on the back side of the movable platen. Therefore, a toggle type mold clamping device other than a mold clamping device that only opens and closes the mold by the toggle mechanism and clamps the mold by another mechanism after engaging the half nut is not the subject of the present invention.

Next, the ejector mechanism 72 attached to the movable platen 14 will be described with reference to FIGS. 2 and 4. FIG. The servomotor 71 for the ejector of the ejector mechanism 72 is fixed to the bracket 70 of the back plate portion as described above, with the drive shaft to which the drive pulley 75 is attached directed toward the stationary platen. Further, as shown in FIG. 6, guide rods 77 are fixed in four guide rod insertion holes 76 in the cross-shaped thin wall portion 60 of the mold mounting portion 40 of the movable platen main body 39 so as to protrude in the mold opening/closing direction. A support plate 78 is fixed to the distal end of the guide rod 77 in parallel with the rear surface 59 of the thin portion 60 . As for the position of the support plate 78 in the mold opening/closing direction, the surface 79 on the side opposite to the mold mounting surface is approximately at the same position as the rear surface 29 of the rear plate portion 68 . That is, the support plate 78 itself is in a state of being completely inserted into or slightly protruding from the concave portion 57 of the movable platen 14 when viewed from the side as shown in FIG.

Two ball screws 80, 80 are rotatably attached to the support plate 78 by bearings, and driven pulleys 81, 81 are attached to the tip ends of the ball screws 80, 80, respectively. A timing belt 82 is stretched between the driving pulley 75 of the servomotor 71 and the two driven pulleys 81,81. The ends of the ball screws 80 , 80 opposite to the tip end side are rotatably supported by bearings provided in the thin portion 60 of the mold mounting portion 40 . Further, an ejector plate 83 is guided by the guide rod 77 so as to be movable in the mold opening/closing direction. Therefore, the ejector plate 83 is provided within the recess 57 formed by the wall surfaces including the inner wall surface 66 of the connecting portion 46 . Two ball screw nuts 84, 84 are fixed to the ejector plate 83, and the ball screws 80, 80 are inserted through the ball screw nuts 84, 84, respectively. A plurality of ejector rods 47 are fixed to the ejector plate 83 on the mold mounting portion 40 side in the mold opening/closing direction.

As described above, the ejector rod 47 is inserted through the rod hole 48 formed in the mold mounting portion 40 and further through the rod hole 74 of the movable mold 13 . And it is in contact with the rear surface of the projecting plate 85 in the movable mold 13 . A plurality of projecting rods 87 are also formed on the cavity surface 86 side of the projecting plate 85 of the movable mold 13 , and the projecting rods 87 are inserted into rod holes 88 formed toward the cavity surface 86 . Also, the protruding rod 87 is returned to its original position by a spring 89 . The ejector mechanism 72 is not limited to the configuration described above, and when an electric motor is used, the ball screw nut may be rotated to move the ball screw forward. Also, the ejector mechanism may be one using an electromagnet, a hydraulic cylinder, an air cylinder, or the like. In any case, the majority of the ejector mechanism 72 including the ejector plate 83 is accommodated in the recess 57 formed by the frame-shaped extended portion 41, so that the mold clamping device 2 and, in turn, the injection molding machine 1 have a total length of can be suppressed.

<Explanation of operation of mold clamping device>
Next, a method for controlling the mold clamping device 2 of the injection molding machine 1 of the first embodiment will be briefly described. First, the ball screw 34 is rotated by the operation of the servo motor 33 of the mold opening/closing mechanism 15 from the mold open state in which the movable platen 14 is retracted, and the ball screw nut 35 inserted through the ball screw 34 is moved in the mold opening/closing direction. , the movable platen 14 and the movable mold 13 stopped at the mold opening position are moved toward the fixed platen 12 and the fixed mold 11 . Then, when the movable mold 13 is brought into mold contact with the fixed mold 11, a cavity c1 into which the molten resin is injected is formed between the fixed mold 11 and the movable mold 13 (mold closing step). Next, each half nut 31 is actuated, and the engaging tooth of the half nut 31 is engaged with the engaging groove 27 of each tie bar 24 (half nut engaging process).

Hydraulic oil is then supplied to the mold clamping side oil chamber 25 of the mold clamping cylinder 17 of the mold clamping mechanism 16 to pull the tie bars 24 to increase the mold clamping pressure. tightened (pressurization process). When it is confirmed that the mold clamping force reaches a predetermined level, the molten resin is injected from the injection device 4 toward the cavity c1 (injection process/mold clamping process).

The states of the fixed platen 12 and the movable platen 14 in the mold clamping process will be described. The clamping force is transmitted. The movable mold 13 is clamped against the fixed mold 11 by the mold clamping force transmitted from the tie bar insertion portion extension 44 of the movable platen 14 to the mold mounting portion 40 . At this time, the reaction force from the mold side is conversely generated from the mold mounting portion 40 of the movable platen 14 toward the extension portion 41 side.

At this time, as in Patent Document 1, the length between the mold mounting surface of the movable platen and the back surface to which the half nut is attached (the mold of the movable platen) relative to the length of one side of the mold mounting surface of the movable platen When the plate thickness in the opening/closing direction) is small, the bending stress acting on the movable platen becomes large, and the bending of the movable platen becomes large. In addition, if the bending of the movable platen is to be suppressed, the plate thickness of the movable platen needs to be increased, resulting in an increase in weight.

On the other hand, in the first embodiment, the mold mounting surface 30 of the movable platen 14 and the mold mounting surface 30 of the movable platen 14 shown in FIGS. Since the length F between the nut 31 and the back surface 29 (thickness of the movable platen in the mold opening/closing direction) is large, the bending stress acting on the movable platen main body 39 of the movable platen 14 is small. deflection becomes smaller. In the present invention, the extending portion 44 of the tie bar insertion portion extending in the mold opening/closing direction of the movable platen main body and the radially thick portion 49 are connected by the connecting portion 46 to form a picture frame shape. Therefore, the tensile stress acting on the portion of the extension portion 41 can be dispersedly received, and as a result, the compressive stress acting on the portion of the mold mounting portion 40 can be reduced.

In addition, in Patent Document 2, cross ribs are required to extend to the center of the movable platen, but in the first embodiment, the movable platen 14 does not need to extend the length of the radial thick portion 49 to the center of the movable platen 14 . As a result, the strength against the deflection of the plate during mold clamping can be ensured, and at the same time, a concave portion can be formed in the center of the back side of the movable platen 14 . This is because the tensile stress acting on the rear side of the radial thick portion 49 of the box-shaped movable platen 14 is dispersed by the outer connecting portion 61 and the inner connecting portion 62 .

In the mold clamping process, mold clamping by the mold clamping cylinder 17 is continued for a predetermined time after injection, and the molten resin injected into the cavity c1 is cooled. When the mold clamping process is completed, the mold clamping side oil chamber 25 of the mold clamping cylinder 17 is connected to the drain, and the pressure of the working oil in the mold clamping side oil chamber 25 is reduced to 0 (depressurization process).

When the depressurization process is completed, hydraulic oil is supplied to the strong mold opening side oil chamber 26 of the mold clamping cylinder 17, and strong mold opening is performed (strong mold opening process). When the movable platen 14 and the movable mold 13 are moved to a predetermined position by the strong mold opening process, the servo motor 33 of the next mold opening/closing mechanism 15 is operated to complete the mold opening of the movable platen 14 and the movable mold 13. Move to the position (mold opening step). At the mold opening completion position, the molded product is ejected from the cavity surface 86 of the movable mold 13 by the operation of the servo motor 71 of the ejector mechanism 72, and is taken out by a take-out device (not shown) (ejecting step). Then, it shifts to the mold closing step of the next molding cycle.

Describing in more detail the operation of the ejector mechanism 72 in the ejecting process, when the servomotor 71 of the ejector mechanism 72 is operated, the rotational force of the drive pulley 75 is transmitted to the two driven pulleys 81, 81 via the timing belt 82. , two ball screws 80, 80 to which driven pulleys 81, 81 are fixed are rotated, respectively. As the ball screws 80, 80 rotate, the ball screw nuts 84, 84 are moved rightward in FIG. As a result, the ejector plate 83 to which the ball screw nuts 84, 84 are fixed and the ejector rod 47 on the side of the movable platen 14 attached to the ejector plate 83 are simultaneously moved rightward in FIG. The ejector rod 47 presses the rear surface of the protruding plate 85 in the movable mold 13, and the protruding rod 87 fixed to the front side of the protruding plate 85 protrudes from the cavity surface 86 to eject the molded product (not shown). .

<Second embodiment>
The second embodiment corresponds to claim 5 and FIG. In FIG. 7, the mold clamping device 102 of the injection molding machine 101 shows the mold open state, the upper half of the center line shows the central cross section of the movable platen 106 and the like, and the lower half of the center line shows the A section of the tie bar 107 portion is shown. A mold clamping device 102 of an injection molding machine 101 according to the second embodiment moves a movable platen 106 to which a movable mold 105 is attached to a fixed platen 104 to which a fixed mold 103 is attached in the mold opening/closing direction along tie bars 107 . In a mold clamping device 102 having a mold opening/closing mechanism 108 for moving and a mold clamping mechanism 109 for clamping the fixed mold 103 and the movable mold 105, the movable platen 106 is a mold to which the movable mold 105 is attached. A first movable platen 111 having a mounting surface 110 and a second movable platen 112 connected to the first movable platen 111 by a mold clamping mechanism 109 are provided. A board main body 114 including an extended part 113 of the tie bar insertion part through which the tie bar 107 is inserted; A connecting portion 116 that connects the portions including the portion 113 and has a hollow portion 115 therein is provided, and a concave portion 117 is formed by a wall surface including the inner wall surface of the connecting portion 116. In the concave portion 117, An ejector plate 119 of an ejector mechanism 118 is arranged either on the first movable platen 111 or between the first movable platen 111 and the second movable platen 112 .

That is, the mold clamping device 102 of the second embodiment has a first movable platen 111 to which a movable mold 105 is attached and a second movable platen having a mold clamping cylinder 120 of a mold clamping mechanism 109 with respect to a fixed platen 104 . A platen 112 is provided, and a ram 121 of a mold clamping cylinder 120 is fixed to the back surface of the first movable platen 111 . The first movable platen 111 and the second movable platen 112 move to open and close the molds on the bed 122 with respect to the fixed platen 104 by the operation of the mold opening/closing mechanism 108 . A member including the extended portions 113 of the tie bar insertion portion extending from the four corners on the back side of the plate main body portion 114 on which the mold clamping cylinder 120 of the second movable plate 112 is provided and the extended portion 113 of the tie bar insertion portion are connected to each other by connecting portions 116 . As shown in the upper half of FIG. 7, the connecting portion 116 is provided with an outer connecting portion 123 and an inner connecting portion 124, and a hollow portion 115 is formed between them.

A frame-shaped extension portion 125 is formed by the extension portion 113 of the tie bar insertion portion, the mold clamping force transmission portion, and the connection portion 116 . The majority of the parts, including A half nut 128 is attached near the tie bar insertion hole 127 on the rear surface 126 of the tie bar insertion portion extension portion 113 of the frame-shaped extension portion 125 . During mold clamping by the mold clamping device 102 of the second embodiment, only the second movable platen 112 is flexurally deformed by the mold clamping force. However, by providing the second movable platen 112 with a frame-shaped extended portion 125, the ratio of the plate thickness in the mold opening/closing direction to the length of one side of the movable platen (for example, the length in the vertical direction) can be increased. Even with the same weight, it is possible to reduce bending deformation during mold clamping. In the second embodiment, when there is one mold clamping cylinder, the ejector mechanism 118 is mounted on the first movable platen 111 or between the first movable platen 111 and the second movable platen 112. may be provided (the motor is attached to the side surface of the first movable platen 111).

<Other embodiments>
In the first embodiment described above, the fixed platen 12 is provided with the mold clamping cylinder 17 , and the movable platen 14 is provided with the half nuts 31 for the tie bars 24 connected to the fixed platen 12 . However, in the present invention, the mold clamping cylinder may be provided on the movable platen and the half nut may be provided on the fixed platen. In this case, the mold mounting portion of the stationary platen has a mortar portion in the center into which the injection device is inserted. A frame-shaped extended portion is further formed from the rear surface of the mold mounting portion other than the mortar portion (opposite mold mounting surface) toward the rear surface side of the board. The extension portion includes a portion including the extension portion of the tie bar insertion portion through which the tie bar is inserted, and a connection portion that connects the portions to each other. The connecting portion is composed of a plurality of ribs and beams for weight reduction, and has a hollow portion inside. A half nut is attached in the vicinity of the tie bar insertion hole through which the tie bar is inserted on the rear surface of the extended portion. In that case, the ejector mechanism may be attached to the concave portion formed by the inside of the frame-shaped extended portion and the mortar. Also in the second embodiment, tie bars may be fixed to the second movable platen, half nuts may be provided to the fixed platen, and the structure of the present invention may be adopted for the fixed platen.

In still another embodiment, a mold mounting portion having a mold mounting surface to which a movable mold of a movable platen is mounted, and a mold mounting portion having a mold mounting surface to which a fixed mold of a fixed platen is mounted. The part may be one that is not inserted into the tie bar. In that case, the board main body is connected to the central pressing portion on the back side of the mold mounting portion. Alternatively, the pressing portion at the center of the board main body is connected to the mold mounting portion. A tie bar insertion portion is formed in a portion of the board main body through which the tie bar is inserted. The tie bar insertion portion extends from the board main body toward the rear side, and a radially thick portion is formed from the extending portion of the tie bar insertion portion toward the center side of the movable board. A radial thickening is also connected to the rear side of the board body. A connection portion is formed to connect the extended portions of the tie bar insertion portion or the extended portions of the tie bar insertion portion and the radially thick portions. The extended portion of the tie bar insertion portion, the radially thick portion, and the connecting portion correspond to the extended portion for increasing the plate thickness of the board. At least the connection portion of the frame-shaped extended portion is hollow inside. A half nut is attached near the tie bar insertion portion on the rear surface (opposite mold mounting surface) of the frame-shaped extended portion. In still another embodiment, the concave portion formed on the back side of the board may be formed by the back wall surface of the board main body and the inner wall surface of the extended portion instead of the mold mounting portion.

Further, the movable platen and the stationary platen of the present invention may be formed by combining a plurality of members instead of forming a single cast body as a whole, as shown in Japanese Patent No. 5567066. That is, the metal mold mounting portion, the board body portion and the extension portion may be separately cast and assembled later.

The connecting portion of the movable platen or fixed platen may be provided with a connecting portion other than the outer connecting portion 61 and the inner connecting portion 62 . Although the connecting portion has a hollow portion, a hole portion connecting the hollow portion and the outside, a hole portion connecting the hollow portions, or a rib connecting the connecting portions are appropriately provided. Further, the connecting part may be of a honeycomb structure having a hollow part therein. In that case, the shape of the honeycomb is not limited to a hexagon, and may be triangular or quadrangular. Alternatively, the connecting portion may have one or more cylindrical members having hollow portions inside in the direction of opening and closing the mold or in the direction of connecting the extending portions of the tie bar insertion portions.

Furthermore, the mold clamping device of the present invention may be a mold clamping device for a rotary mold injection molding machine in which a rotary table is attached to the surface of a stationary platen or a movable platen. In that case, the rotary table on which the mold is mounted on the mold mounting surface corresponds to the mold mounting portion, and the plate body portion of the movable platen or the fixed platen is connected to the rear side of the mold mounting portion. Further, a frame-shaped extended portion composed of a member including the extended portion of the tie bar insertion portion of the present invention, a connecting portion, and the like is formed on the outer periphery of the board main body portion on the back side. A half nut is attached in the vicinity of the tie bar insertion portion on the rear surface of the extended portion. A recess is formed from the rear wall surface of the board body and the inner wall surface of the extension. In the case of a mold rotary injection molding machine to which a rotary table is attached, in addition to the ejector mechanism, the concave portion is provided with a rotating motor of the rotary table and a pipe for feeding the temperature control medium from the rotary shaft of the rotary table to the mold. mechanism or the like can also be provided.

Furthermore, the mold clamping device of the present invention may be provided with a rotatable intermediate plate between the stationary platen and the movable platen. In that case, the board provided with the connection portion of the present invention may be at least one of a fixed board and a movable board. The use of the present invention is not very useful for a plate that is hardly deformed by a mold clamping force during mold clamping, such as the intermediate plate. In the mold clamping device of the present invention, a tie bar is passed between a fixed platen and a pressure receiving plate corresponding to the fixed platen, a movable platen is moved on the tie bar or the bed by a mold opening/closing mechanism, and a mold clamping mechanism is used to clamp the mold. It may be something that is done. In this case, the pressure-receiving plate provided on the bed and moved only slightly during mold clamping corresponds to the fixed plate of the present invention, and employs a box-shaped structure having a recess on the back side.

Further, the mold opening/closing direction of the movable platen in the mold clamping device of the present invention is not limited to the horizontal direction, and a vertical mold clamping device in which the movable platen opens/closes the molds in the vertical direction may be used. In this case, the movable platen of the present invention may be an upper platen whose molds are opened and closed above the fixed platen, or a lower platen whose molds are opened and closed below the fixed platen. Also, the present invention may be used for a stationary platen of a vertical mold clamping device. Although the mold clamping force of the mold clamping device of the injection molding machine of the present invention is not particularly limited, as an example, a large mold clamping device having a mold clamping force of 8,000 kN or more is more preferably used.

Although the present invention is not enumerated one by one, it is needless to say that the present invention is not limited to the above-described ones, and modifications made by those skilled in the art based on the spirit of the present invention are also applied. A plurality of examples described above can also be implemented in combination as appropriate. The control method using the mold clamping device of the present invention includes general mold clamping control that continues from the start of injection to the end of cooling in a completely pressurized state, injection compression molding control, injection press molding control, foam molding It may be used for control such as control. Also, the type of material to be molded and the type of molded product are not limited.

1 Injection molding machine 2 Mold clamping device 11 Fixed mold 12 Fixed platen 13 Movable mold 14 Movable platen 15 Mold opening and closing mechanism 16 Mold clamping mechanism 20, 30 Mold mounting surface 21, 29 Back surface 24 Tie bar 31 Half nut 40 Mold mounting Part 41 Extension part 44 Extension part of tie bar insertion part 45 Cavity part 46 Connection part 57 Recess 60 Thin part 61 Outer connection part 62 Inner connection part 66 Inner wall surface 72 Ejector mechanism 83 Ejector plate

Claims (5)

A mold opening/closing mechanism that moves a movable platen, to which a movable mold is attached, in a mold opening/closing direction along tie bars with respect to a fixed platen, to which a fixed mold is attached, and a mold clamping mechanism that clamps the fixed mold and the movable mold. In a mold clamping device with
The fixed platen or the movable platen is
a plurality of extended portions through which tie bars are inserted;
a connecting portion that connects the adjacent extending portions among the plurality of extending portions and has a hollow portion therein ;
A mold clamping device, wherein the extended portion and the connecting portion are provided on a surface of the stationary platen or the movable platen opposite to a mold mounting surface. A mold opening/closing mechanism that moves a movable platen, to which a movable mold is attached, in a mold opening/closing direction along tie bars with respect to a fixed platen, to which a fixed mold is attached, and a mold clamping mechanism that clamps the fixed mold and the movable mold. In a mold clamping device with
The fixed platen or the movable platen is
a plurality of extended portions through which tie bars are inserted;
an outer connecting portion that connects outer portions of adjacent extending portions among the plurality of extending portions ;
an inner connecting portion that connects inner portions of adjacent extending portions among the plurality of extending portions ;
A frame-shaped extension having at least
A mold clamping device, wherein the extended portion is provided on a surface of the fixed platen or the movable platen opposite to a mold mounting surface . 3. A half nut is attached near an end portion of the tie bar insertion hole provided in the extension portion and through which the tie bar is inserted, on the side away from the mold mounting surface. mold clamping device. A mold opening/closing mechanism that moves a movable platen, to which a movable mold is attached, in a mold opening/closing direction along tie bars with respect to a fixed platen, to which a fixed mold is attached, and a mold clamping mechanism that clamps the fixed mold and the movable mold. In a mold clamping device with
The movable platen is
a mold mounting portion having a mold mounting surface to which the movable mold is mounted;
a plurality of extended portions connected to the back side of the mold mounting portion and through which tie bars are inserted;
a connecting portion that connects the adjacent extending portions among the plurality of extending portions and has a hollow portion therein;
A mold clamping device, wherein an ejector plate of an ejector mechanism is arranged in a recess formed by a wall surface including an inner wall surface of the connecting portion. A mold opening/closing mechanism that moves a movable platen, to which a movable mold is attached, in a mold opening/closing direction along tie bars with respect to a fixed platen, to which a fixed mold is attached, and a mold clamping mechanism that clamps the fixed mold and the movable mold. In a mold clamping device with
The movable platen includes a first movable platen having a mold mounting surface to which a movable mold is mounted, and a second movable platen connected to the first movable platen by a mold clamping mechanism ,
The second movable board includes a board main body section including a plurality of extended portions through which the tie bars are inserted;
a connecting portion extending from the outer edge of the rear surface of the board main body, connecting the adjacent extending portions of the plurality of extending portions and having a hollow portion therein;
A wall surface including the inner wall surface of the connecting portion forms a recess, and an ejector plate of the ejector mechanism is arranged in the recess, the first movable platen, or between the first movable platen and the second movable platen. Also, the mold clamping device.

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