Injection molding apparatus

Abstract

The present invention provides an injection molding apparatus that can reduce the temperature difference in the circumferential direction of the cylindrical portion of the preform. [Solution] An injection molding apparatus comprising a columnar female mold portion with a recess formed inside, and a peripheral member provided around the female mold portion so as to cover at least a part of the outer peripheral surface of the female mold portion, wherein a hole is formed in the peripheral member in a direction intersecting the center line direction of the female mold portion, and a groove is formed around the entire circumference of the female mold portion at a position outside the recess and opposite to the hole, and a flow path is formed in the hole of the peripheral member and the groove of the female mold portion for a medium to flow to cool the recess.

Description

Technical Field

[0005] , , ,

[0001] The present invention relates to an injection molding apparatus.

Background Art

[0002] For example, the parison mold used for injection blow molding and composed of a plurality of split molds described in Patent Document 1 is configured as follows. That is, the split mold has a split mold main body, a cooling insert disposed in the split mold main body for partially cooling the parison, and a floating device that floats the cooling insert from the split mold main body when the mold is opened to provide a gap between the two.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when the final molded product is a bottle container molded using PET (Polyethylene Terephthalate), it is desirable that the circumferential temperature difference of the test tube-shaped preform (in other words, parison) used for blow molding is small. This is because when the circumferential temperature difference in the preform is small, it is easier for the preform to uniformly expand in the entire circumference during blow molding, and the quality of the final molded product is improved. An object of the present invention is to provide an injection molding apparatus capable of reducing the circumferential temperature difference of the cylindrical portion of a preform.

Means for Solving the Problems

[0005] The present invention, completed with this objective in mind, is an injection molding apparatus comprising: a columnar female mold portion with a recess formed inside; and a peripheral member provided around the female mold portion so as to cover at least a part of the outer peripheral surface of the female mold portion, wherein the peripheral member has a hole formed therein that extends in a direction intersecting the centerline direction of the female mold portion, and the female mold portion has a groove formed around its entire circumference at a position outside the recess and opposite to the hole, recessing from the outer peripheral surface, and a flow path is formed in the hole of the peripheral member and the groove of the female mold portion for a medium to flow to cool the recess. Here, the groove may be larger in the direction of the center line than its depth. Furthermore, the groove may have a partition wall in the central part in the direction of the centerline that separates one side of the groove from the other side in the direction of the centerline. Furthermore, the partition wall may have a notch formed in a part of its circumferential direction that allows the one side portion and the other side portion to pass through each other. Furthermore, the notch may be formed at a position opposite to the hole. Furthermore, the female mold portion may have a gate formed therein that serves as an inlet for resin into the recess, and on the outside of the gate, there may be a cross recess formed in a direction that intersects the outer peripheral surface in the direction of the center line, through which the medium flows. Furthermore, the distance between the bottom of the intersecting recess and the gate may be smaller than the distance between the bottom of the groove and the recess. [Effects of the Invention]

[0006] According to the present invention, the temperature difference in the circumferential direction of the cylindrical portion of the preform can be reduced. [Brief explanation of the drawing]

[0007] [Figure 1] This is a view in the vertical direction of an example of a cross-section of an injection molding machine according to an embodiment. [Figure 2] This is a view in a second direction showing an example of a cross-section of an injection molding machine according to the embodiment. [Figure 3](a) is a diagram showing an example of a cross-section of the preform before molding. (b) is a diagram showing an example of a cross-section of the preform after molding. [Figure 4] (a) is a diagram showing an example of a cross-section of the final molded product before molding. (b) is a diagram showing an example of a cross-section of the final molded product after molding. [Figure 5] This figure shows an example of the appearance of the female mold section. [Figure 6] This figure shows an example of a cross-section of the female mold and cavity plate. [Figure 7] This figure shows an example of a cross-section of section VII-VII in Figure 6. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described in detail below with reference to the attached drawings. Figure 1 is a view in the vertical direction of an example of a cross-section of an injection blow molding machine 1 according to an embodiment. Figure 2 is a view of an example of a cross-section of the injection blow molding machine 1 according to the embodiment, as seen in a second direction. Figure 3(a) shows an example of a cross-section of the preform 610 before molding. Figure 3(b) shows an example of a cross-section of the preform 610 after molding. Figure 4(a) shows an example of a cross-section of the final molded product 600 before molding. Figure 4(b) shows an example of a cross-section of the final molded product 600 after molding. Figures 1 and 2 show the mold after it has been opened.

[0009] The injection and blow molding machine 1 is a device that performs injection molding (in other words, injection molding) and blow molding (in other words, blow molding). The injection and blow molding machine 1 forms an intermediate molded product, such as a test tube-shaped preform 610, by injection molding, and then forms a final molded product 600, such as a container, by blow molding, which expands the inside of the preform 610 by blowing high-pressure air into it.

[0010] The injection molding machine 1 comprises a fixed mold 10, a movable mold 20 that is movable relative to the fixed mold 10, and an intermediate mold 30 positioned between the fixed mold 10 and the movable mold 20. The injection molding machine 1 performs injection molding at the injection station between the fixed mold 10 and the intermediate mold 30 by closing the molds of the fixed mold 10 and the intermediate mold 30. The injection molding machine 1 also performs blow molding at the blow station between the intermediate mold 30 and the movable mold 20 by closing the molds of the intermediate mold 30 and the movable mold 20. Hereafter, the direction of movement of the movable mold 20 relative to the fixed mold 10 (in other words, the left and right directions in Figures 1 and 2) may be referred to as the "first direction." In the first direction, the side on which the fixed mold 10 is positioned may be referred to as the "first side," and the side on which the movable mold 20 is positioned may be referred to as the "second side." The injection molding machine 1 is positioned such that the up and down direction in Figure 2 is the top and bottom direction. In the following, the vertical direction in Figure 2 may be simply referred to as the "vertical direction." Furthermore, the direction perpendicular to the first direction and the vertical direction (in other words, the vertical direction in Figure 1) may be referred to as the "second direction."

[0011] The injection molding machine 1 includes a fixed platen 11 fixed to a frame 500 fixed to the floor and holding a fixed mold 10, and a movable platen 21 slidably mounted on a guide member 510 on the frame 500 and holding a movable mold 20. The injection molding machine 1 also includes an intermediate mold support frame 31 slidably mounted on the guide member 510 between the fixed platen 11 and the movable platen 21 and supporting an intermediate mold 30.

[0012] Furthermore, the injection molding machine 1 includes an injection device (not shown) that injects resin into a cavity 17 formed between the fixed mold 10 and the intermediate mold 30, on the side opposite to the fixed mold 10 relative to the fixed platen 11. In addition, the injection blow molding machine 1 includes a mold clamping device (not shown) on the side opposite to the movable mold 20 with respect to the movable platen 21. The mold clamping device has a mold clamping cylinder device (not shown) for driving the movable platen 21 and a support plate (not shown) to which the mold clamping cylinder device is attached. The support plate and the fixed platen 11 are connected by a plurality (for example, four) of tie bars 520. The fixed platen 11 is fixed to the frame 500 by bolts or the like. The movable platen 21 and the intermediate mold support frame 31 are mainly supported from below by guide members 510 and move in the first direction along the tie bars 520.

[0013] The injection blow molding machine 1 further includes a plurality of female mold parts 12 and a cavity plate 13 provided around the female mold parts 12 so as to cover at least a part of the outer peripheral surface 120 of the plurality of female mold parts 12. In the present embodiment, a total of 12 female mold parts 12 are provided so as to form two columns arranged in six rows in the vertical direction, and a cavity plate 13 into which the 12 female mold parts 12 are fitted is attached to the fixed mold 10.

[0014] The movable mold 20 has a movable blow split mold 22, a first bottom mold 23, a second bottom mold 24, and a suction device 25 for sucking the final molded product 600. The movable injection split mold 22 has a driving-side movable part 22a and a driven-side movable part 22b which are arranged opposite to each other. The driving-side movable part 22a and the driven-side movable part 22b are moved in the second direction by the split mold driving cylinder device 26 to come into close contact with or separate from each other. And when the driving-side movable part 22a and the driven-side movable part 22b come into close contact with each other, a female mold 27 for injection molding is formed. In the present embodiment, six female molds 27 for injection molding arranged in the vertical direction in a set of the driving-side movable part 22a and the driven-side movable part 22b are formed, and two sets of the driving-side movable parts 22a and the driven-side movable parts 22b are arranged side by side in the second direction. The driving-side movable part 22a is connected to the piston rod 26a of the split mold driving cylinder device 26 and is directly moved by the split mold driving cylinder device 26. The driven-side movable part 22b is connected to the driving-side movable part 22a of the other set and is moved in the second direction so as to come into contact with or separate from the driving-side movable part 22a of its own set. The split mold driving cylinder device 26 can be exemplified as, for example, a pneumatic cylinder device.

[0015] The first bottom mold 23 is attached to the movable platen 21. A through hole 23a penetrating in the first direction is formed in the first bottom mold 23. The through hole 23a is arranged on the extension line of the center line of the final molded product 600 in the state where the driving-side movable part 22a and the driven-side movable part 22b are mold-closed, and forms a space in which the second bottom mold 24 can be arranged. Around the through hole 23a in the first bottom mold 23, a recess 23b recessed from the contact surface with the movable injection split mold 22 is formed.

[0016] The second bottom mold 24 is a columnar member and is arranged in the through hole 23a of the first bottom mold 23. The second bottom mold 24 is arranged so as to slightly protrude to the first side in the first direction from the recess 23b of the first bottom mold 23. The diameter of the second bottom mold 24 is slightly smaller than the diameter of the through hole 23a of the first bottom mold 23. Therefore, a gap is formed between the first bottom mold 23 and the second bottom mold 24 in the state where the second bottom mold 24 is arranged in the through hole 23a.

[0017] The suction device 25 consists of a vacuum pump and the like, and sucks up the final molded product 600. Specifically, the suction device 25 sucks up the final molded product 600 using the gap formed between the first bottom mold 23 and the second bottom mold 24 as an air passage during suction.

[0018] The intermediate mold 30 includes a rotating frame 35 that is rotatably attached to the intermediate mold support frame 31, and a core mold frame 50 that is not rotatably attached to the intermediate mold support frame 31. Here, the intermediate support frame 31 comprises rectangular parallelepiped-shaped legs 32, which are positioned at both ends in the second direction and are shaped such that the vertical direction is the longitudinal direction and the first direction is the short direction; a top plate 33u connecting the upper parts of both legs 32; and a bottom part 33b connecting the lower parts of both legs 32. A cylindrical support column 34 is fixed to the vertical center of each leg 32, and is attached so as to penetrate the leg 32 in the second direction. Furthermore, through holes (not shown) in the first direction for passing tie bars 520 are formed in the upper and lower parts of each leg 32.

[0019] The rotating frame 35 is attached to the outer circumference of the support column 34 via bearing members 36 such as ball bearings, and is rotatable relative to the intermediate support frame 31 with the centerline of the support column 34 as the center of rotation. In this embodiment, an annular driven gear 37 is attached to the side surface of the rotating frame 35, and a drive gear 38b attached to the rotating shaft 38a of the electric motor 38 meshes with the driven gear 37. As a result, the rotating frame 35 rotates around the support column 34 when the electric motor 38 is operated.

[0020] The intermediate mold 30 includes a plurality of guide bars 39 attached to the rotating frame 35 so as to extend in a first direction, a gripping frame 40 slidably attached to the guide bars 39 in the first direction, and a limiting portion 45 that restricts the movement of the gripping frame 40 relative to the guide bars 39. In this embodiment, in the open state shown in Figures 1 and 2, the intermediate mold 30 has one guide bar 39 at the first end of the rotating frame 35, and one at the upper and lower ends of each end in the second direction. In addition, the rotating frame 35 has one guide bar 39 at the second end, and one at the upper and lower ends of each end in the second direction. In other words, the intermediate mold 30 according to this embodiment has a total of eight guide bars 39. However, the intermediate mold 30 may also have guide bars extending to both the fixed mold 10 side and the movable mold 20 side at the upper and lower ends of each end in the second direction, for a total of four guide bars.

[0021] In the state shown in Figures 1 and 2, one gripping frame 40 is provided at each end of the first direction of the rotating frame 35. The gripping frame 40 is slidably attached to four guide bars 39, which are located on the same side with respect to the centerline of the support column 34, and is also lockable and unlockable to the tips 39a of the guide bars 39. In the state shown in Figures 1 and 2, the gripping frame 40 is locked to the tips 39a of the guide bars 39 by a limiting portion 45, preventing it from sliding relative to the guide bars 39. When the engagement between the limiting portion 45 and the tips 39a of the guide bars 39 is released, the gripping frame 40 becomes slidable relative to the guide bars 39.

[0022] The gripping frame 40 has a gripping device 41 for forming and gripping the mouth portion 620 of the final molded product 600. The gripping device 41 includes a screw split mold 42 for forming and gripping the mouth portion 620, a slide plate 43 to which the screw split mold 42 is attached, and a gripping release member 44 for releasing the grip of the mouth portion 620. The gripping release member 44 is driven by a gripping release drive device (not shown). The screw split mold 42 forms the mouth portion 620 in a closed state during injection molding and grips the mouth portion 620 in a closed state during blow molding. The screw split mold 42 also releases the mouth portion 620 by opening the mold after the completion of blow molding.

[0023] More specifically, the screw mold 42 is configured to be separable in a second direction, with each half of the screw mold 42 attached to the half of the slide plate 43. The half of the slide plate 43 is also attached to the gripping frame 40 so as to be slidable in the second direction. The gripping release member 44 is configured to be separable in a second direction, with each half of the gripping release member 44 attached to the half of the slide plate 43. When the gripping release member 44 is pushed open in the second direction, the half of each slide plate 43 and the half of each screw mold 42 are also pushed open and separated in the second direction. This releases the grip of the mouth 620 of the final molded product 600 after the blow molding is completed at the blow station. In this embodiment, the screw split mold 42 is provided at positions corresponding to the female mold portion 12 attached to the fixed mold 10 and the female mold 27 for blow molding of the movable blow split mold 22. In other words, in the state shown in Figures 1 and 2, the screw split mold 42 forms two rows of six pieces arranged vertically.

[0024] The limiting section 45 is also releasably connected to the tip (not shown) of an injection-side member (not shown) attached to the fixed platen 11, and is operated by the tip of the injection-side member to lock or unlock the tip 39a of the guide bar 39. Furthermore, the limiting section 45 is also releasably connected to the tip (not shown) of a blowing-side member (not shown) attached to the movable platen 21, and is operated by the tip of the blowing-side member to lock or unlock the tip 39a of the guide bar 39.

[0025] The core formwork 50 is fixed to the support column 34, thereby being non-rotatably attached to the intermediate support frame 31. An injection core mold 51 is attached to the side of the core mold 50 facing the fixed platen 11, and a blowing guide 52 is attached to the side of the core mold 50 facing the movable platen 21. The injection core mold 51 has a base portion 51a and a male mold portion 51b, and in the closed state, it forms a cavity 17 between itself and the female mold portion 12 that has the shape of the preform 610. The blowing guide 52 has a base portion 52a and, when in a closed state, is in close contact with the entrance of the female mold 27 for blow molding, which is formed by the close contact of the drive-side movable portion 22a and the driven-side movable portion 22b, and forms a space for blow molding that has the shape of the final molded product 600.

[0026] The intermediate mold 30 also includes a stretch rod 53 that can protrude from the base portion 52a of the blowing guide 52, a connecting plate 54 to which the base portions of the multiple stretch rods 53 are attached, and a stretch rod drive device 55 for protruding the stretch rods 53. The stretch rod drive device 55 can be exemplified as, for example, a pneumatic cylinder device. The stretch rod drive device 55 can be exemplified as being attached to the upper and lower outer surfaces of the core mold 50. The connecting plate 54 is connected to the piston rod of the stretch rod drive device 55. When the stretch rod drive device 55 is operated, the connecting plate 54 connected to the piston rod moves, and the stretch rod 53 protrudes into the preform 610. In this embodiment, the final molded product 600 is formed from the preform 610 by stretch-blow molding, in which the stretch rod 53 is made to protrude into the preform 610, and high-pressure air is blown into the preform 610 while stretching it.

[0027] Furthermore, the injection molding machine 1 includes an intermediate mold drive cylinder device 15 that moves the intermediate mold support frame 31 in a first direction relative to the fixed platen 11, and a connecting rod 16 connected to the piston rod of the intermediate mold drive cylinder device 15. The intermediate mold drive cylinder device 15 is fixed to the fixed platen 11, and the connecting rod 16 is attached to the intermediate mold support frame 31. By operating the intermediate mold drive cylinder device 15, the intermediate mold support frame 31 can be moved relative to the fixed platen 11. As a result, the injection molding machine 1 can perform injection molding and blow molding by closing, clamping, and opening the mold at separate timings in the injection station and the blowing station.

[0028] Furthermore, the injection molding machine 1 has a control device 70 that controls the injection molding machine 1. The control device 70 has a CPU (Central Processing Unit) (not shown), a ROM (Read Only Memory) (not shown) which is a memory area for storing programs, and a RAM (Random Access Memory) (not shown) which is a program execution area. The control device 70 realizes various functions by having the CPU execute programs stored in the ROM or a storage device such as an HDD (Hard Disk Drive) or semiconductor memory. The control device 70 also receives detection results from various sensors. Based on the detection results from the various sensors, the control device 70 controls the operation of the injection device (not shown), the clamping device (not shown), the intermediate mold drive cylinder device 15, the electric motor 38, the grip release drive device (not shown), the stretch rod drive device 55, etc. The operation of the injection molding machine 1, which is performed based on the control by the control device 70, will be described below.

[0029] (operation) In this embodiment, the injection blow molding machine 1, in one molding cycle, forms 12 preforms 610 equal to the number of female molds 12 by injection molding at the injection station. In addition, at the blow station, the injection blow molding machine 1 uses the same number of preforms 610 formed at the injection station in the previous molding cycle to perform blow molding and form 12 final molded products 600.

[0030] First, as shown in Figures 1 and 2, the mold opens at the injection station and blowing station, and a mold clamping device (not shown) activates to begin closing the mold. This causes the movable platen 21 to move from the open state to the closed state, that is, closer to the fixed platen 11. While the movable platen 21 is moving from the open state to the closed state, the intermediate mold drive cylinder device 15 activates, causing the intermediate mold support frame 31 to move from the open state to the closed state, that is, closer to the fixed platen 11.

[0031] Furthermore, as the intermediate support frame 31 approaches the fixed platen 11, the limiting portion 45 of the gripping frame 40, which is engaged with the tip 39a of the guide bar 39 attached to the side of the rotating frame 35 on the fixed platen 11 side, comes into contact with the tip (not shown) of the injection-side member (not shown) attached to the fixed platen 11. As a result, the engagement between the limiting portion 45 and the tip 39a of the guide bar 39 is released, and the lock between the gripping frame 40 and the guide bar 39 is released.

[0032] Similarly, as the movable platen 21 moves from the open mold state to the closed mold state, the intermediate mold support frame 31 approaches the movable platen 21. Then, the limiting portion 45 of the gripping frame 40, which is engaged with the tip 39a of the guide bar 39 attached to the side of the rotating frame 35 on the movable platen 21 side, comes into contact with the tip (not shown) of the blowing side member (not shown) attached to the fixed platen 11. As a result, the engagement between the limiting portion 45 and the tip 39a of the guide bar 39 is released, and the lock between the gripping frame 40 and the guide bar 39 is released. Before the movable platen 21 moves from the open state to the closed state, the split mold drive cylinder device 26 is activated, causing the drive-side movable part 22a and the driven-side movable part 22b to move in the second direction and close, forming the female mold 27 for blow molding.

[0033] Then, when the movable platen 21 is in the closed position, the mold closing is completed at the injection station and the blowing station. In this case, the gripping frame 40 at the injection station and the blowing station is released from its lock with the guide bar 39, and is pushed by the injection-side member (not shown) or the blowing-side member (not shown) to slide relative to the guide bar 39 and come into contact with the core mold 50.

[0034] In this case, as shown in Figure 3(a), at the injection station, each male mold portion 51b is inserted into each female mold portion 12 attached to the fixed mold 10. A cavity 17 is formed between the inner surface of the female mold portion 12 and the screw split mold 42 and the outer surface of the male mold portion 51b. Then, as shown in Figure 3(b), the resin injected by the injection device fills the cavity 17. Even after the resin filling is complete, the mold remains closed to cool the resin in the cavity 17. In this way, a preform 610 having a cylindrical body portion 611 and a hemispherical tip portion 612 is molded at the injection station.

[0035] In the blowing station, as shown in Figure 4(a), the screw split die 42, which is gripping the mouth 620 of the preform 610, is pressed against the opening of the blow-molding female mold 27, which is formed by the drive-side movable part 22a and the driven-side movable part 22b. As a result, the flange of the preform 610 is pressed against the outer surface of the opening of the blow-molding female mold 27, and the part beyond the flange enters the inside of the blow-molding female mold 27. Also, the tip 52b of the base 52a of the blowing guide 52 enters the mouth 620 of the preform 610. Then, the stretch rod drive device 55 is activated, and the stretch rod 53 protrudes toward the back of the blow-molding female mold 27, and at the same time, high-pressure air is blown into the inside of the preform 610, causing the preform 610 to expand and press against the inner surface of the blow-molding female mold 27. As a result, as shown in Figure 4(b), a bottle-shaped or bottle-shaped bottomed container having the shape of the inner surface of the female mold 27 for blow molding is formed as the final molded product 600. When the stretching is complete, the stretching rod 53 is returned to its original position from its protruding state. Then, when the blow molding is complete, the clamping force applied to the movable platen 21 by the mold clamping device is released.

[0036] Subsequently, while maintaining the positional relationship between the drive-side movable part 22a and the driven-side movable part 22b and the gripping device 41, the movable platen 21 moves away from the core mold 50. Then, when a predetermined gap is formed between the screw split mold 42 and the blowing guide 52, the drive-side movable part 22a and the driven-side movable part 22b move in a second direction. The screw split mold 42 is also pushed open in the second direction, opening the mouth 620. Then, when the distance between the drive-side movable part 22a and the driven-side movable part 22b becomes at least greater than the outer diameter of the final molded product 600, the final molded product 600 falls downward from between the drive-side movable part 22a and the driven-side movable part 22b. The final molded product 600 is discharged below the injection blowing molding machine 1 and stored in a storage device (not shown).

[0037] Subsequently, the intermediate mold drive cylinder device 15 operates, causing the intermediate mold support frame 31 to move from the mold closed state to the mold open state, that is, away from the fixed platen 11. Since the limiting portion 45 of the gripping frame 40 in the injection station is fitted with the tip portion (not shown) of the injection side member (not shown), the gripping frame 40 slides in the axial direction of the guide bar 39 even when the intermediate mold support frame 31 moves toward the mold open state. Therefore, the screw split mold 42 remains fitted in the vicinity of the entrance of the female mold portion 12. As a result, the core mold frame 50 moves together with the intermediate mold support frame 31, and the male mold portion 51b is pulled out from the female mold portion 12 attached to the fixed mold 10.

[0038] Subsequently, when the gripping frame 40 reaches the tip 39a of the guide bar 39, the limiting portion 45 disengages from the tip of the injection-side member and engages with the tip 39a of the guide bar 39, thus locking the gripping frame 40 and the guide bar 39 together. Therefore, as the intermediate support frame 31 moves further away from the fixed platen 11, the gripping frame 40 also moves with it, and the screw split mold 42 is pulled out from the female mold portion 12. In this case, the split portion of the screw split mold 42 is biased toward the center by the biasing member and is coupled to each other, so it grips the mouth 620 of the preform 610. As a result, the gripping frame 40 in the injection station reaches a position away from the fixed mold 10 with the screw split mold 42 gripping all 12 preforms 610.

[0039] Next, the electric motor 38 is activated, causing the rotating frame 35 to rotate around the centerline of the support column 34. As a result, the gripping frame 40 in which the screw mold 42 grips the preform 610 moves from the injection station to the blowing station, and the other gripping frame 40 moves from the blowing station to the injection station. Then, when the rotation of the rotating frame 35 is complete, the mold opens at the injection station and the blowing station. This completes one molding cycle. Thereafter, the above operation is repeated, and a predetermined number of molding cycles are repeated.

[0040] The female mold section 12 and the cavity plate 13 will be described in detail below. Figure 5 shows an example of the appearance of the female mold part 12. Figure 6 shows an example of a cross-section of the female mold section 12 and the cavity plate 13. Figure 7 shows an example of a cross-section of section VII-VII in Figure 6. The female mold portion 12 is cylindrical in shape. Inside the female mold portion 12, there is a first recess 121 recessed from the first end face toward the second side in the first direction, a second recess 122 recessed from the second end face toward the first side in the first direction, and a central hole 123 that connects the first recess 121 and the second recess 122.

[0041] The first recess 121 is the entry point for the resin injected by the injection device (not shown) into the female mold 12. The second recess 122 is a recess that conforms to the outer shape of the preform 610. The second recess 122 has a hemispherical portion 124 provided on the first side and a cylindrical portion 125 provided on the second side. A cavity 17 (see Figure 3(a)) is formed when the male mold portion 51b is inserted into the second recess 122. The central hole 123 is a cylindrical through-hole formed between the first recess 121 and the second recess 122. The center line of the central hole 123 is formed to be the same as the center line of the cylindrical portion 125, and the diameter of the central hole 123 is smaller than the diameter of the cylindrical portion 125. The central hole 123 serves as an inlet for the resin injected by an injection molding device (not shown) into the cavity 17. In other words, the central hole 123 functions as a gate for filling the second recess 122, which functions as the product portion, with resin.

[0042] In the female mold portion 12, a groove 126 recessed from the outer surface 120 is formed around the entire circumference of the second recess 122. The groove 126 is formed in the portion corresponding to the cylindrical portion 125 of the second recess 122. The width W of the groove 126 is greater than the depth D in the first direction. The groove 126 has a partition wall 127 in the center in the first direction that separates the portion on the first side (an example of one side) from the portion on the second side (an example of the other side). The size of the partition wall 127 in the first direction is smaller than the diameter of the second side upper and lower through hole 142, which will be described later. The partition wall 127 has a notch 128 formed in a part in the circumferential direction that allows the portion of the groove 126 on the first side of the partition wall 127 to pass through to the portion on the second side. Two notches 128 are formed at equal intervals in the circumferential direction. The notch 128 is formed at a position corresponding to the second upper and lower through hole 142, which will be described later, and it can be illustrated that the circumferential size of the notch 128 is the same as the diameter of the second upper and lower through hole 142.

[0043] Furthermore, the female mold portion 12 has multiple (two in this embodiment) intersecting recesses 129 formed circumferentially in a cylindrical shape from the outer peripheral surface 120 in a direction intersecting the first direction (orthogonal in Figure 6). The intersecting recesses 129 are formed in the area corresponding to the central hole 123 of the second recess 122. In addition, the intersecting recesses 129 are formed in the position corresponding to the first upper and lower through holes 141, which will be described later, and it can be exemplified that the diameter of the intersecting recesses 129 is the same as the hole of the first upper and lower through holes 141. The depth D2 of the intersecting recesses 129 is greater than the depth D of the groove 126.

[0044] The cavity plate 13 is rectangular in shape. When viewed in the first direction, it is molded so that the vertical direction is the longitudinal direction and the second direction is the short direction. The cavity plate 13 has cylindrical first through holes 130 in the first direction into which the female mold part 12 is fitted. There are a total of 12 first through holes 130, forming two rows of six holes each in the vertical direction.

[0045] Furthermore, vertical through-holes 140 are formed inside the cavity plate 13. The vertical through-holes 140 include a first-side vertical through-hole 141 provided on the first side and a second-side vertical through-hole 142 provided on the second side. The first-side vertical through-hole 141 and the second-side vertical through-hole 142 are each formed in two in the second direction, corresponding to each row of six first through-holes 130. The vertical through-holes 140 are formed to connect the vertically aligned first through-holes 130 to each other. The vertical through-holes 140 are also formed to connect the uppermost and lowermost first through-holes 130 among the six vertically aligned first through-holes 130 to the outside of the cavity plate 13. In addition, the vertical through-holes 140 are formed to pass through the center of the six aligned first through-holes 130. The vertical through-holes 140 can be exemplified as being cylindrical in shape.

[0046] In this embodiment, a cavity plate 13, which is an example of a surrounding member, is provided around and holds a part of the female mold portion 12 so as to cover it. That is, the female mold portion 12 is fitted into each of the first through holes 130 formed in the cavity plate 13, and the position of the female mold portion 12 is maintained by the cavity plate 13. For example, the female mold portion 12 is press-fitted into the first through holes 130. In addition, in the first direction, the intersecting recess 129 of the female mold portion 12 faces the first upper and lower through holes 141 on the cavity plate 13, and the partition wall 127 of the groove 126 of the female mold portion 12 faces the second upper and lower through holes 142 on the cavity plate 13. Furthermore, in the circumferential direction of the female mold portion 12, the intersecting recess 129 of the female mold portion 12 is fitted so as to face the first upper and lower through holes 141 of the cavity plate 13, and the notch 128 of the partition wall 127 of the groove 126 of the female mold portion 12 is fitted so as to face the second upper and lower through holes 142 of the cavity plate 13.

[0047] Water is supplied to the intersecting recesses 129 of the female mold portion 12 via the first upper and lower through holes 141 of the cavity plate 13, thereby functioning as a first water channel through which water flows to cool the central hole 123 of the female mold portion 12. The number of intersecting recesses 129 formed around the central hole 123 of the female mold portion 12 is not limited, and there may be three or more intersecting recesses 129. For example, three or more intersecting recesses 129 can be formed radially around the central hole 123. Alternatively, holes can be formed in the cavity plate 13 to correspond to each of the multiple intersecting recesses 129, and water can be supplied to the intersecting recesses 129 through these holes. Furthermore, the multiple intersecting recesses 129 may be configured to be interconnected, allowing water to flow between them.

[0048] Furthermore, water is supplied to the groove 126 of the female mold part 12 through the second upper and lower through holes 142 of the cavity plate 13, causing water to flow around the cylindrical portion 125 of the second recess 122 of the female mold part 12. The second upper and lower through holes 142 of the cavity plate 13 and the groove 126 of the female mold part 12 function as second water channels through which water flows to cool the inside of the female mold part 12.

[0049] More specifically, water supplied from the upper part of the second upper and lower through-hole 142 flows from the second upper and lower through-hole 142 into the uppermost groove 126 of the female mold part 12, which is fitted into the uppermost of the six first through-holes 130. As described above, the size of the partition wall 127 of the female mold part 12 in the first direction is smaller than the diameter of the second upper and lower through-hole 142, so as shown in Figure 6, the water flows from the second upper and lower through-hole 142 into both the part of the groove 126 that is first and second to the partition wall 127. The water that has flowed into the part of the groove 126 that is first and second to the partition wall 127 flows in a clockwise and counterclockwise direction, respectively, as shown in Figure 7. In other words, the water that has passed through the second upper and lower through-hole 142 and reached the groove 126 of the female mold part 12 branches into four directions. The water, which has branched out in four directions, then reaches the bottom of the groove 126, merges, and flows into the second side upper and lower through hole 142 formed below the female mold section 12.

[0050] The center of the second upper and lower through-hole 142 coincides with the partition wall 127 of the groove 126, but since the second upper and lower through-hole 142 and the notch 128 correspond to each other, the reduction in the water flow area caused by providing the partition wall 127 in the groove 126 is suppressed. In other words, the notch 128 is formed so that the flow area in the second upper and lower through-hole 142 matches the opening area in the groove 126 to the second upper and lower through-hole 142. This makes it possible for the cooling water to flow smoothly through the second water channel.

[0051] On the other hand, the female mold portion 12 is subjected to a clamping force in the first direction when the mold is clamped. In addition, the female mold portion 12 is subjected to injection pressure resulting from the injection of resin into the cavity 17, and the pressure of water supplied into the grooves 126 and intersecting recesses 129. Therefore, the female mold portion 12 needs to have sufficient strength to withstand the clamping force, injection pressure, and water pressure. However, if the grooves 126 formed in the female mold portion 12 are made larger, it becomes difficult to ensure sufficient strength to withstand the clamping force, injection pressure, and water pressure. In the female mold portion 12 according to this embodiment, partition walls 127 are provided in the grooves 126, so that the strength does not become less than the strength to withstand the clamping force due to an increase in the width W of the grooves 126.

[0052] The injection blow molding machine 1 described above is an example of an injection molding apparatus comprising a female mold section 12 which is columnar and has a second recess 122 (an example of a recess) formed inside that conforms to the outer shape of the preform 610, and a cavity plate 13 (an example of a peripheral member) provided so as to be in contact with the periphery of the female mold section 12 so as to cover at least a part of the outer peripheral surface 120 of the female mold section 12. The cavity plate 13 has a second upper and lower through hole 142 (an example of a hole) formed therein that extends in a direction intersecting the first direction (an example of the centerline direction) of the female mold section 12. The female mold section 12 has a groove 126 formed around its entire circumference, recessed from the outer peripheral surface 120, outside the second recess 122 and facing the second upper and lower through hole 142. The cavity plate 13 and the female mold section 12 are in contact so that water flowing through the second upper and lower through hole 142 of the cavity plate 13 and the groove 126 of the female mold section 12 does not leak out. This creates a channel through which water (an example of a medium) that cools the second recess 122 flows.

[0053] Here, in order to cool the second recess 122, we consider a female mold part according to the comparative example in which, for example, a hole perpendicular to the first direction and not extending in the circumferential direction is formed on the outside of the second recess 122, similar to the intersecting recess 129. In the case of the female mold part according to the comparative example, since areas with holes and areas without holes are mixed in the circumferential direction on the outside of the second recess 122, the temperature difference in the circumferential direction of the preform 610 becomes large. In contrast, with the injection blow molding machine 1 according to this embodiment, a flow path is formed by the groove 126 formed over the entire circumference, so the temperature difference in the circumferential direction of the preform 610 becomes small.

[0054] Furthermore, the width W of the groove 126 is greater than the depth D. Therefore, the temperature of the preform 610 decreases over a wide area in the first direction. However, by making the distance L1 between the bottom of the groove 126 and the second recess 122 greater than, for example, the distance L2 between the bottom of the intersecting recess 129 and the central hole 123, the excessive temperature drop of the preform 610 due to the large width W is suppressed. Also, even in the area around the second recess 122 in the female mold part 12, there is a mixture of areas where the groove 126 is formed and areas where the groove 126 is not formed in the first direction, but by reducing the depth D, the large temperature difference between the areas with and without the groove 126 is suppressed.

[0055] Furthermore, if, for example, a narrow groove is formed spirally around the second recess 122, the body 611 of the preform 610 will have alternating portions in the first direction that are inside the spiral groove and portions that are not inside the groove. Also, when the groove is formed spirally, the cooling water is heated as it flows through the spiral groove, resulting in different temperatures on the upstream and downstream sides. As a result, it is difficult to reduce the temperature difference in the first direction in the body 611 of the preform 610. In contrast, in the groove 126 according to this embodiment, a groove with a large width W is formed around the entire circumference, so the temperature difference in the first direction in the body 611 of the preform 610 is reduced.

[0056] Furthermore, the female mold section 12 has a central hole 123 (an example of a gate) which serves as an inlet for resin into the second recess 122, and a cross recess 129 is formed outside the central hole 123, recessed in a direction that intersects the first direction from the outer peripheral surface 120. The depth D2 of the cross recess 129 is greater than the depth D of the groove 126. As the inside of the central hole 123 is cooled by the cross recess 129, the preform 610 becomes easier to separate from the second recess 122 of the female mold section 12. On the other hand, the diameter of the cross recess 129 is smaller than the width W of the groove 126, and the cross recess 129 is not formed around the entire circumference, so the strength is prevented from becoming less than the strength that can withstand the clamping force, injection pressure, and water pressure, which would result from making the depth D2 of the cross recess 129 greater than the depth D of the groove 126.

[0057] Furthermore, the gap between the outer circumferential surface 120 of the female mold portion 12 and the inner circumferential surface of the first through hole 130 of the cavity plate 13 is sealed by O-rings 150 fitted into grooves formed at both ends of the female mold portion 12 in the first direction. Therefore, even if water is supplied to the grooves 126 and intersecting recesses 129 formed in the female mold portion 12 through holes formed in the cavity plate 13 (e.g., upper and lower through holes 140), leakage of water from the gap between the female mold portion 12 and the cavity plate 13 is suppressed.

[0058] Furthermore, the liquid used for cooling is not limited to water. For example, the liquid used for cooling may be oil. Also, the medium used for cooling is not limited to a liquid; it may be a gas. Furthermore, the cooling mechanism for the preform 610, which is composed of the female mold section 12 and the cavity plate 13 described above, may also be applied to the injection molding section of an apparatus equipped with a heating section that heats the preform 610 after it has been molded and before blow molding is performed. [Explanation of Symbols]

[0059] 1…Injection blow molding machine, 10…Fixed mold, 11…Fixed platen, 12…Female mold section, 13…Cavity plate (example of surrounding component), 17…Cavity, 20…Movable mold, 21…Movable platen, 35…Rotating frame, 40…Gripping frame, 41…Gripping device, 42…Screw split mold, 50…Core mold frame, 120…Outer surface, 122…Second recess (example of recess), 123…Central hole (example of gate), 126…Groove, 127…Partition wall, 128…Notch, 129…Intersecting recess, 130…First through hole, 141…First side upper and lower through holes, 142…Second side upper and lower through holes (example of hole), 600…Final molded product, 610…Preform

Claims

1. A female mold part that is columnar and has a recess formed inside, A peripheral member provided around the female mold portion so as to cover at least a portion of the outer surface of the female mold portion, Equipped with, The surrounding member has holes formed in a direction that intersects the centerline direction of the female mold portion. The female mold portion has a groove formed around its entire circumference, recessed from the outer surface, at a position outside the recess and facing the hole. A flow path is formed in the hole of the surrounding member and the groove of the female mold portion through which a cooling medium flows to the recess. Injection molding equipment.

2. The groove has a size in the direction of the center line that is greater than its depth. The injection molding apparatus according to claim 1.

3. The groove has a partition wall in the center of the direction of the centerline that separates one side of the groove from the other side of the groove. The injection molding apparatus according to claim 2.

4. The partition wall has a notch formed in a part of its circumferential direction that allows the one side portion and the other side portion to pass through. The injection molding apparatus according to claim 3.

5. The notch is formed in a position opposite to the hole. The injection molding apparatus according to claim 4.

6. The female mold portion has a gate that serves as an inlet for resin into the recess, and outside the gate, there is a cross recess formed in a direction that intersects the outer peripheral surface in the direction of the center line, through which the medium flows. The injection molding apparatus according to claim 1.

7. The distance between the bottom of the intersecting recess and the gate is smaller than the distance between the bottom of the groove and the recess. The injection molding apparatus according to claim 6.

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