Blow molding apparatus for resin-made container

Abstract

A blow molding apparatus for resin containers includes: an injection molding unit that injects resin material into an injection mold to create a bottomed cylindrical preform; a temperature adjustment unit that adjusts the temperature of the preform obtained from the injection molding unit; and a blow molding unit that blow molds the temperature-adjusted preform while it is still hot from the injection molding process, thereby manufacturing a resin container. The injection molding unit includes: an injection device that injects resin material into an injection mold under the control of a first motor; a mold opening and closing mechanism that opens and closes the injection mold via a second motor; and a hydraulic cylinder that closes the injection mold after it has closed.

Description

Technical Field

[0001] This invention relates to a blow molding apparatus for resin containers. Background Technology

[0002] For example, in blow molding apparatuses for hot-formed resin containers, there is a need to further shorten the molding cycle and reduce operating costs in order to improve productivity. Therefore, as shown in Patent Document 1, electrification is being gradually promoted to replace hydraulic drive in such blow molding apparatuses.

[0003] Prior art literature Patent documents Patent Document 1: Japanese Patent No. 4912715 Summary of the Invention The technical problem that the invention aims to solve However, if the blow molding equipment is fully electrified, the drive unit will become larger in areas requiring greater force, which has the disadvantage of increasing equipment cost.

[0004] Therefore, the present invention was made in view of the following problems, and its object is to provide a blow molding apparatus for resin containers that can be electrified and reduce equipment costs.

[0005] Technical solutions for solving technical problems One aspect of the present invention provides a blow molding apparatus for a resin container, comprising: an injection molding unit that injects resin material into an injection mold to produce a bottomed cylindrical preform; a temperature adjustment unit that adjusts the temperature of the preform obtained from the injection molding unit; and a blow molding unit that blow molds the temperature-adjusted preform while it is still hot from the injection molding process, thereby producing a resin container. The injection molding unit includes: an injection device that injects resin material into the injection mold under the control of a first motor; a mold opening and closing mechanism that opens and closes the injection mold via a second motor; and a hydraulic cylinder that closes the injection mold after it has been closed.

[0006] Invention Effects According to one aspect of the present invention, a blow molding apparatus for resin containers can be provided, which can be electrified and reduce equipment costs. Attached Figure Description

[0007] Figure 1 This is a schematic top view of the blow molding apparatus according to this embodiment.

[0008] Figure 2 It means Figure 1 A rough side view of the injection molding section in the mold-open state.

[0009] Figure 3 It means Figure 1 A rough side view of the injection molding section in the closed state.

[0010] Figure 4 This is a front view showing the mold opening state of the injection molding section.

[0011] Figure 5 Is with Figure 4 The corresponding longitudinal section view.

[0012] Figure 6 This is a diagram showing an example of a lifting mechanism for a temperature control unit.

[0013] Figure 7 This is a diagram showing an example of the structure of a blow molding part in the mold-open state.

[0014] Figure 8 This is a diagram showing an example of the structure of a blow molding section in the closed mold state.

[0015] Figure 9 This is a flowchart illustrating the various steps of blow molding based on the blow molding apparatus of this embodiment. Detailed Implementation

[0016] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0017] In the embodiments, to facilitate understanding, structures and elements other than the main parts of the invention are simplified or omitted in the description. Furthermore, in the drawings, the same symbols are used to denote the same elements. Additionally, the shapes, dimensions, etc., of the elements shown in the drawings are schematic and do not represent actual shapes, dimensions, etc.

[0018] <Description of Blow Molding Equipment> Figure 1 This is a schematic top view of a blow molding apparatus including a mold opening and closing device. Figure 2 It means Figure 1 A rough side view of the injection molding section in the mold-open state. Figure 3 It means Figure 1 A rough side view of the injection molding section in the closed state. Figure 4 This is a front view showing the mold opening state of the injection molding section. Figure 5 Is with Figure 4 The corresponding longitudinal section view.

[0019] The blow molding apparatus 1 of this embodiment is a hot preform method (also known as a one-stage method) that effectively utilizes the heat retained during injection molding (internal heat) to perform blow molding without cooling the preform 20 to room temperature.

[0020] like Figures 1-3 As shown, the blow molding apparatus 1 includes: a machine base 2, and an upper base 10 disposed above the machine base 2 (in the Z direction of the figure). The upper base 10 is supported by a plurality of pillars (not shown) erected upward from the machine base 2.

[0021] In the blow molding apparatus 1, an injection molding unit 4, a temperature adjustment unit 5, a blow molding unit 6, and a take-out unit 7 are arranged in the space between the machine base 2 and the upper base 10. In addition, the operation of each element of the blow molding apparatus 1 is controlled by a control unit (not shown).

[0022] The injection molding unit 4, temperature adjustment unit 5, blow molding unit 6, and take-out unit 7 are positioned at a given angle (e.g., 90 degrees) each time the transfer plate 12 rotates, with reference to the rotation center O of the transfer plate 12 described later. Furthermore, the temperature adjustment unit 5 and take-out unit 7 are not necessarily required in the blow molding apparatus 1.

[0023] Here, at the position of the injection molding section 4 on the upper base 10, the upper mold plate 32 of the injection molding section 4... Figure 2 The injection core molds 24 shown are respectively disposed on the upper surface side. At the temperature adjustment section 5 of the upper base 10, a temperature adjustment rod and a temperature adjustment rod lifting mechanism (neither shown) are disposed on the upper surface side. At the blow molding section 6 of the upper base 10, a stretching rod and a stretching rod lifting mechanism (neither shown) are respectively disposed on the upper surface side. Additionally, a take-out cam (not shown) is disposed at the take-out section 7 of the upper base 10.

[0024] Additionally, four fan-shaped transfer plates 12 are arranged at intervals of a given angle (e.g., 90 degrees) above the machine base 2 and on the lower surface of the upper base 10. The four transfer plates 12 are respectively fixed to multiple support members (not shown) on the lower surface of the upper base 10 and to receiving members 46A and 46B (see reference 46A) provided on the injection molding section 4. Figure 2 , Figure 3 Guided by the transfer plate 12, the preform 20 (or container) moves intermittently and cyclically along the rotation direction with the rotation center O as the rotation axis. The preform 20 (or container) held by the transfer plate 12 is conveyed in the order of injection molding section 4, temperature adjustment section 5, blow molding section 6, and take-out section 7 by the rotation of the transfer plate 12.

[0025] In addition, such as Figure 2 , Figure 3As shown, a neck mold 22 is provided on the lower surface of each transfer plate 12. The neck mold 22 holds the pre-plastic preform 20 in a vertical direction along its axial direction. In addition, an opening is formed on the upper surface of the neck mold 22 in each transfer plate 12, through which the injection core mold 24, blow molding core, and tension rod can be inserted into or removed from the pre-plastic preform 20 from above.

[0026] (Injection molding section 4) The injection molding unit 4 includes: an injection mold 21; a mold opening and closing mechanism 31 for opening and closing the injection mold 21; and a lifting mechanism 40 for raising and lowering the neck mold 22 or a transfer plate 12 to which the neck mold 22 is fixed relative to the injection cavity mold 26. An injection device 3 is connected to the injection molding unit 4, which supplies resin material as raw material for the preform.

[0027] Here, the injection device 3 includes an injection cylinder 3a, an injection screw 3b, and a drive actuator 3c. Furthermore, the injection device 3 may also include a shut-off device (not shown) and a pressure-holding device (not shown), wherein the shut-off device shuts off the connection between the injection screw 3b and the injection nozzle, and the pressure-holding device is used to maintain pressure after the resin material is injected.

[0028] An injection screw 3b is held inside the injection cylinder 3a. The injection screw 3b can rotate relative to the injection cylinder 3a and can move forward and backward by driving the actuator 3c. In addition, a hopper (not shown) for supplying resin material is connected to the injection cylinder 3a, and resin material is supplied into the injection cylinder 3a from the hopper. In order to melt the solid resin material contained between the inner wall of the injection cylinder 3a and the groove of the injection screw 3b, the injection cylinder 3a is set to a high temperature above the melting point of the resin material.

[0029] A screw head 3b1 is provided at the front end of the injection screw 3b. The injection screw 3b heats the solid resin material inside the injection cylinder 3a by rotating, causing it to become molten (plasticized). In the metering step of the injection molding process, the injection screw 3b retracts while filling (supplying) molten resin material forward of the screw head 3b1. Then, after the resin material filling is completed, in the injection step of the injection molding process, the injection screw 3b is advanced in a non-rotating state by driving the actuator 3c, thereby injecting the molten resin material.

[0030] Furthermore, the drive actuator 3c of the injection device 3 is a servo motor (an example of the first motor), which drives the screw head 3b1 of the injection screw 3b in the forward and backward direction via a ball screw-based screw feed mechanism. The drive actuator 3c also includes a first servo motor and a second servo motor. The first servo motor is used to rotate the injection screw 3b in metering processes, etc., and the second servo motor is used to move the injection screw 3b forward or backward in a non-rotating state during injection processes, etc.

[0031] Furthermore, the aforementioned injection mold 21 includes: an injection core mold 24, which defines the internal shape of the preform 20; an injection cavity mold 26, which defines the external shape of the preform 20; a hot runner mold 28, which guides the molten resin supplied from the injection unit 3 into the mold space of the injection mold 21; and a neck mold 22, which defines the external shape of the neck (opening) of the preform 20. The injection cavity mold 26 and the hot runner mold 28 are fixed to the lower assembly mold 34 mounted on the machine base 2. On the other hand, the injection core mold 24 is mounted on the upper assembly mold 32 supported by connecting rods 38A and 38B, and can be raised and lowered in the vertical direction (the Z direction, which is the vertical direction).

[0032] The injection molding unit 4 closes the injection cavity mold 26, the injection core mold 24, and the neck mold 22 of the transfer plate 12 to form a mold space in the shape of a preform. Then, by injecting resin material from the injection device 3 into such a mold space in the shape of a preform, the injection molding unit 4 manufactures the preform 20.

[0033] The lifting mechanism 40 is an example of a transfer plate lifting mechanism, comprising: receiving members 46A and 46B that hold the transfer plate 12; lifting rods 44 and 45 that extend downward from the receiving members 46A and 46B; and a drive unit 42 (in Figure 2 , Figure 3 (Not shown in the diagram), the receiving components 46A and 46B are raised and lowered via lifting rods 44 and 45. Receiving component 46A is positioned outside the rotation radius direction of the transfer plate 12 and connected to the lifting rod 45. Receiving component 46B is positioned on the rotation center O side of the transfer plate 12 and connected to the lifting rod 44. The lifting rods 44 and 45 are connected within the machine base 2 by a connecting member 48.

[0034] like Figure 4 , Figure 5As shown, the drive unit 42 includes: a servo motor 42a (an example of a third motor); a ball screw 42b driven by the servo motor 42a; and a belt 42c that transmits the power of the servo motor 42a to the ball screw 42b. The drive unit 42 is fixed to the lower surface and side surface of the lower assembly template 34, and two are arranged within the machine base 2. The ball screw 42b of the drive unit 42 is connected to the connecting member 48. The lifting mechanism 40, driven by the servo motor 42a of the drive unit 42, causes the connecting member 48 to rise and fall within the machine base 2, thereby causing the receiving members 46A and 46B to rise and fall vertically via lifting rods 44 and 45. Consequently, the transfer plate 12 held by the receiving members 46A and 46B rises and falls vertically.

[0035] The mold opening and closing mechanism 31 causes the generally triangular upper mold plate 32, positioned above the transfer plate 12, to move vertically relative to the machine base 2. Multiple (e.g., four) injection core molds 24 are fixed to the lower surface of the upper mold plate 32 via a fixing plate 23. The upper mold plate 32 is fixed to the upper end of multiple (e.g., three) cylindrical connecting rods 38A and 38B extending upward from the machine base 2. Two connecting rods 38A are positioned on the outer side in the direction of rotation radius, and one connecting rod 38B is positioned on the side of the rotation center O. The connecting rods 38A and 38B are fixed near the vertices of the triangular shape of the upper mold plate 32.

[0036] Additionally, the lower ends of connecting rods 38A and 38B are respectively fixed to the lower movable plate 36 disposed within the machine base 2. Furthermore, as... Figure 4 , Figure 5 As shown, a mold-closing cylinder 50 and a drive unit 52 are disposed between the lower surface of the lower mold-closing plate 34 and the lower movable plate 36. A shielding mechanism (not shown) is provided on the upper surface of the lower movable plate 34, which allows a pressure plate (not shown) that abuts against the lower end of the rod member 51a (described later) to open and close. The opening and closing mechanism opens the pressure plate when the upper mold-closing plate 32 rises, allowing the rod member 51a to pass through relative to the lower movable plate 36 (eliminating interference between the rod member 51a and the lower movable plate 36). In addition, the shielding mechanism closes the pressure plate when the upper mold-closing plate 32 descends and is in the closed mold position (or mold-closing position), and during the mold-closing operation, the lower end of the rod member 51a abuts against the pressure plate, thereby bearing pressure.

[0037] The mold closing mechanism includes at least a mold closing cylinder 50, a piston rod 51, and a rod member (pressure rod) 51a fixed to the lower end of the piston rod 51 and extending downward. The mold closing cylinder 50 is fixed to the lower surface of the lower mold closing platen 34 and disposed within the machine base 2. The mold closing cylinder 50 is, for example, a hydraulic cylinder, which performs the function of applying a high-pressure mold closing force to the injection mold 21 in the mold closing direction during injection molding.

[0038] The drive unit 52 includes: a servo motor 52a (an example of a second motor); a mold opening / closing ball screw 52b driven by the servo motor 52a; and a belt (not shown) that transmits power from the servo motor 52a to the ball screw 52b. The drive unit 52 is fixed to the lower surface of the lower mold plate 34, and two such drive units are arranged within the machine base 2. The mold opening / closing ball screw 52b of the drive unit 52 is connected to the lower movable plate 36. The mold opening / closing mechanism 31, driven by the servo motor 52a of the drive unit 52, causes the lower movable plate 36 to rise and fall within the machine base 2, thereby causing the upper mold plate 32 to rise and fall vertically via connecting rods 38A and 38B. This performs the mold opening and closing action of the injection core mold 24, fixed to the upper mold plate 32, rising and falling vertically.

[0039] Furthermore, even when the injection molding section 4 is opened, the neck mold 22 of the transfer plate 12 does not open, and the preform 20 is still held and conveyed. The number of preforms 20 simultaneously molded by the injection molding section 4 (i.e., the number of containers that can be simultaneously molded by the blow molding apparatus 1) can be appropriately set. As an example, a structure for conveying 6 preforms 20 is shown in the accompanying drawings.

[0040] Additionally, although not specifically limited, the servo motor 42a and belt 42c of drive unit 42 and the servo motor 52a and belt (not shown) of drive unit 52 can also be arranged in the lower part of the lower mold plate 34. Alternatively, one of the drive units 42 and 52 can be located on the side of the injection device 3 (for example, the servo motor 52a and belt (not shown) of drive unit 52 is provided on one side), and the other of the drive units 42 and 52 can be located on the side opposite to the injection device 3 and on the side of the lower mold plate 34 (for example, the servo motor 42a and belt 42c of drive unit 42 is provided on the other side). By arranging the drive units 42 and 52 as described above, it is possible to prevent the drive units 42 and 52 from obstructing the operation during molding operations and mold changing operations performed by operators.

[0041] (Temperature adjustment unit 5) The temperature adjustment unit 5 uses a mold unit (not shown) to homogenize and remove temperature deviations in the preform 20 manufactured by the injection molding unit 4, adjusting the temperature of the preform 20 to a suitable blow molding temperature (e.g., approximately 90°C to 105°C) for final blow molding. Furthermore, the temperature adjustment unit 5 in this embodiment also functions to cool the hot preform 20 after injection molding.

[0042] The mold unit of the temperature adjustment section 5 is, for example, a combination of a heating tank and a mold (a temperature adjustment mold disposed on the upper side, such as a temperature adjustment rod and an air inlet member) inserted into the pre-plasticized blank 20. The heating tank is a cavity mold (a temperature adjustment mold disposed on the lower side) that contains the pre-plasticized blank 20 and heats it from the surroundings in a non-contact manner. Alternatively, the mold unit may be a structure that blows compressed air into the pre-plasticized blank 20 for cooling and temperature adjustment. For example, the mold unit described above has a cavity mold (temperature adjustment tank) and an air inlet member, the cavity mold being able to contain the pre-plasticized blank 20, and the air inlet member abutting against the neck to introduce compressed air into the pre-plasticized blank 20.

[0043] In the temperature adjustment unit 5, the cavity mold C (heating tank, temperature regulating tank) that houses the pre-plasticized blank 20 in the mold unit can be raised and lowered in the vertical direction by a mold lifting mechanism driven by a servo motor 67 (an example of a fourth motor).

[0044] Figure 6 This figure shows an example of the mold lifting mechanism 60 of the temperature adjustment unit 5. The mold lifting mechanism 60 includes: a support platform 61 disposed at the lower part of the cavity mold C; multiple guide rods 62 that guide the support platform 61 in the vertical direction; and a crank portion 64 having a crank rod 63. The crank rod 63 is in a generally L-shaped form. The upper end of the crank rod 63 is supported by the lower shaft of the support platform 61. The lower end of the crank rod 63 is supported by the upper shaft of a connecting rod member 67a, which is fixed to the rotation shaft of the servo motor 67. The crank portion 64 drives the crank rod 63 connected to the lower part of the support platform 61 via the connecting rod member 67a through the rotation of the rotation shaft of the servo motor 67, causing the support platform 61 to rise and fall in the vertical direction. When the support platform 61 rises, the pre-plasticized blank 20 held by the transfer plate 12 is housed in the cavity mold C placed on the support platform 61. When the support platform 61 falls, the cavity mold C placed on the support platform 61 retracts from the pre-plasticized blank 20 held by the transfer plate 12. Thus, in the temperature adjustment unit 5, the pre-plasticized blank 20 can be inserted into or removed from the cavity mold C without moving the transfer plate 12 and the pre-plasticized blank 20 in the vertical direction.

[0045] Additionally, a height adjustment mechanism (a buffer mechanism corresponding to mold thickness changes) 66 is disposed at the lower part of the support platform 61 between it and the cavity mold C. The height adjustment mechanism 66 is disposed between the support platform 61 and the upper end of the crank rod 63. The height adjustment mechanism 66 includes: a first fixed plate 66b, which is connected to the lower surface of the support platform 61; a second fixed plate 66c, which supports the upper end of the crank rod 63; and a height adjustment member 66a, which is disposed between the first fixed plate 66b and the second fixed plate 66c. In addition, the height adjustment member 66a has an elastic member (such as a compression coil spring). More than one height adjustment member 66a is provided between the first fixed plate 66b and the second fixed plate 66c, preferably four members are provided at the four corners of these fixed plates. The second fixed plate 66c can move up and down relative to the height adjustment member 66a. Alternatively, a spacer member 68 may be disposed between the upper surface of the support platform 61 and the plate-shaped member 65 on which the cavity mold C is fixed.

[0046] Because the cavity mold C of the temperature adjustment unit 5 expands at high temperatures, the dimensions (e.g., length) of the cavity mold C will vary depending on whether it is fixed to the support table 61 at a low temperature or during molding operation at a given temperature. For example, in blow molding (e.g., the blow molding method disclosed in Japanese Patent No. 6505344) during the cooling of the preform 20 in the injection mold after the shortening and holding pressure is completed, compressed air is blown into the preform 20 in the temperature adjustment unit 5 to cool and adjust the temperature. At this time, it is necessary to make the air inlet member and the cavity mold C (can mold) fit tightly in the temperature adjustment unit 5, but at the top dead center of the crank portion 64, the two may not fit tightly. To ensure a strong, tight fit between the two components, the support platform 61 needs to be pressed upwards when the upper and lower ends of the crank 63 are on a vertical line (a straight line) and the upper end of the crank portion 64 (crank 63) reaches the top dead center (the position where the strongest mold-closing force is generated). However, if the cavity mold C expands, the support platform 61 will descend by an amount equivalent to the expansion length of the cavity mold C at the mold-closing position of the air inlet member and the cavity mold C. In this case, the support platform 61 cannot be pressed down at the top dead center position of the crank portion 64 (crank 63), and the pressing force on the support platform 61 is weakened. As a result, due to the force of the air from the air inlet member, the two components are prone to mold opening during molding.

[0047] By arranging a height adjustment mechanism 66 at the lower part of the support platform 61, even if the size (length) of the cavity mold C changes, the second fixing plate 66c moves upward due to the contraction of the height adjustment member 66a. Therefore, the support platform 61 can be pressed upward at the position where the upper end of the crank member 64 (or crank rod 63) reaches the top dead center. Thus, air leakage caused by the air inlet member not being in close contact with the cavity mold C (can mold) at the top dead center of the crank part 64 can be avoided. In addition, the temperature adjustment unit 5 can be used to ensure that the temperature adjustment mold arranged on the lower side and the temperature adjustment mold arranged on the upper side are closed with good positional accuracy.

[0048] (Blow Molding Section 6) The blow molding section 6 stretches and blow molds the pre-plasticized preform 20, which has been temperature-adjusted by the temperature adjustment section 5, to manufacture a container.

[0049] Figure 7 This is a diagram showing an example of the structure of the blow molding section 6 in the mold-open state. Figure 8 This is a diagram showing an example of the structure of the blow molding section 6 in the closed mold state.

[0050] The blow molding unit 6 has a blow mold opening and closing mechanism 70. The blow mold opening and closing mechanism 70 is connected to the blow mold unit 70a. The blow mold opening and closing mechanism 70 has a closing platen 72, a mold closing part 73, and a mold opening and closing part 75 on the machine base 2. The blow mold unit 70a has at least a blow cavity parting mold 71 and a bottom mold 74. A pair of closing platens 72 and a pair of mold closing parts 73 are each arranged on the machine base 2. A pair of blow cavity parting molds 71 ​​are connected to a pair of closing platens 72. The bottom mold 74 is connected to a bottom mold lifting mechanism arranged between a pair of closing platens 72. In addition, although not shown in the figures, the blow molding unit 6 also has a first lifting mechanism and a second lifting mechanism. The first lifting mechanism moves a tension rod up and down, and the second lifting mechanism moves an air inlet member having a blow molding core up and down. The tension rod and the air inlet member are part of the mold unit 70a, arranged above the closed position of the blow cavity parting mold 71, and inserted into the preform 20.

[0051] A pair of blow molding cavity parting molds 71 ​​are molds that form molding spaces (cavities) with a specified container shape. The blow molding cavity parting molds 71 ​​are aligned along... Figure 7 , Figure 8 The parting surface 71a in the vertical direction is used to divide the material, thus enabling it to be able to... Figure 7 , Figure 8 It opens and closes in the left and right directions. The blow molding cavity parting mold 71... Figure 8 In the closed mold state, it is used to form the preform 20 (in Figure 8 (Not shown in the figure) Blow molding cavity for a given container shape. In addition, bottom mold 74 is a mold that defines the bottom shape of the container and is vertically and vertically disposed below the closed position of the blow molding cavity parting mold 71.

[0052] A pair of mold plates 72 are arranged opposite each other across the blow molding cavity parting mold 71, and are respectively fixed to the back side (the side opposite to the parting surface 71a) of the blow molding cavity parting mold 71 or the back side of the blow molding mold fixing plate connected to the blow molding cavity parting mold 71. A piston 73a of the mold closing part 73 is connected to the back side of each mold plate 72. Thus, the mold closing force from the mold closing part 73 is transmitted to the blow molding cavity parting mold 71 via the mold plate 72.

[0053] A pair of mold-closing sections 73 are hydraulic actuators, each having a piston 73a and a cylinder 73b. The cylinder 73b of the mold-closing section 73 is fixed to the machine base 2. Hydraulic control causes the piston 73a to move linearly along the mold-closing direction, thereby driving the mold-closing platen 72. The mold-closing section 73... Figure 8 In the closed mold state, the mold is closed by applying pressure to the parting mold 71 of the blow molding cavity in the mold-closing direction. The piston 73a has: a first piston 73a1, which is connected to the mold-closing platen 72; and a second piston 73a2, which is housed in the cylinder 73b and can move forward and backward, and has a receiving space 73a3 inside for the first piston 73a1 to enter. In addition, in each mold-closing part 73, a spline (not shown) is formed on the piston 73a1, and a receiving member 77 corresponding to the shape of the spline is provided on the cylinder 73b side. Furthermore, the mold-closing part 73 has an opening and closing mechanism 77a (part of the receiving member 77), which switches the interference state and non-interference state of the spline relative to the piston 73a1 by the rotation of the receiving member 77 caused by the motor member (not shown), thereby fixing the position of the piston 73a1.

[0054] The mold closing action of a pair of blow molding cavity parting molds 71 ​​is as follows. First, the piston 73a1 and the mold closing platen 71 are moved towards the mold closing direction by the mold opening and closing part 75 (described later), so that the piston 73a1 exits from the receiving space 73a3 of the piston 73a2 and comes to rest in a position where it does not interfere with the receiving member 77. Next, the receiving member 77 on the cylinder body 73b side is rotated by a motor (not shown), so that the spline-shaped corresponding part of the receiving member 77 interferes with the spline of the piston 73a1. Finally, hydraulic oil flows in the cylinder 73b, so that the mold closing force is transmitted in the order of the second piston 73a2, the receiving member 77, the first piston 73a1, and the mold closing platen 72, thus closing the blow molding cavity parting mold 71. The mold opening action is the reverse of the above.

[0055] Additionally, the mold opening / closing section 75 includes: a servo motor 75a (an example of a fifth motor); and left and right helical screws 75b, which extend along the mold opening / closing direction and have threads etched on one and the other sides of the axial direction in different orientations. The left and right helical screws 75b are connected to the servo motor 75a via a belt 75c, and the closing mold plates 72 are directly or indirectly connected to the threaded portions of the left and right helical screws 75b in different orientations. In the mold opening / closing section 75, if the left and right helical screws 75b rotate driven by the servo motor 75a, a pair of closing mold plates 72 are driven along the left and right helical screws 75b in the mold opening direction or the mold closing direction.

[0056] (Removal section 7) The take-out section 7 opens the neck mold 22 via the take-out cam, removing the container manufactured by the blow molding section 6 from the blow molding apparatus 1. The container taken out by the take-out section 7 is either boxed or conveyed to the filling line.

[0057] Figure 9 This is a flowchart showing the various processes (blow molding cycle) of blow molding performed by the blow molding apparatus 1 of this embodiment.

[0058] (Step S101: Injection molding process) First, in the injection molding section 4, resin is injected from the injection device 3 into the mold space of the preform shape formed by the injection cavity mold 26, the injection core mold 24 and the neck mold 22 to produce the preform 20.

[0059] After the injection molding process is completed, the transfer plate 12 is rotated by a given angle, and the preform 20 held by the neck mold 22 is transported to the temperature adjustment section 5.

[0060] Here, the injection unit 3 of the injection molding section 4 is driven by a motor (3c). Therefore, compared with hydraulic control, the metering of resin material, the responsiveness of the injection screw 3b during injection, and the positional accuracy are all improved, making it easier to form the preform 20 with high quality and homogeneity. In addition, the shape accuracy of the preform 20 is improved, thereby improving the quality and reproducibility of the blow-molded container. Furthermore, the electrification of the injection unit 3 makes it easier to adjust the preform 20 in the injection molding section 4, thus reducing overall molding defects and suppressing the amount of waste resin.

[0061] Furthermore, both the mold opening / closing mechanism 31 and the lifting mechanism 40 of the injection molding section 4 are driven by electric motors (52a, 42a). Therefore, compared to the case where the mold opening / closing action of the injection mold 21 and the lifting action of the transfer plate 12 are performed hydraulically, the responsiveness and positional accuracy are higher, and the drying time is shortened. In addition, compared to hydraulic control that requires a motor to be constantly driven to maintain hydraulic pressure, the mold opening / closing mechanism 31 and the lifting mechanism 40 not only consume less electricity, but also reduce the amount of cooling water used for the working oil.

[0062] On the other hand, the mold closing of the injection mold 21 in the injection molding section 4 is performed by a mold closing cylinder 50, which is a hydraulic cylinder. By using a hydraulic mechanism for the mold closing of the injection mold 21, which requires a large load, the cost of the device can be significantly reduced compared to a structure that uses an electric motor for mold closing.

[0063] (Step S102: Temperature adjustment process) Next, in the temperature adjustment unit 5, temperature adjustment is performed to bring the temperature of the preform 20 close to the temperature suitable for final blow molding.

[0064] During the temperature adjustment process, the preform 20 is housed in the cavity of the mold unit by the drive of the mold lifting mechanism 60. Then, a temperature adjustment rod is inserted into the preform 20 housed in the cavity.

[0065] In the temperature adjustment process, the preform 20 is temperature-adjusted via the cavity mold and temperature adjustment rod to ensure that the preform 20 is not lower than the temperature suitable for blow molding, and also to reduce the temperature deviation generated during injection molding. Afterwards, the temperature of the preform 20 is maintained at the blow molding temperature until blow molding is performed.

[0066] After the temperature adjustment process, the transfer plate 12 is rotated by a given angle, and the temperature-adjusted preform 20, held by the neck mold 22, is conveyed to the blow molding section 6.

[0067] Here, in the temperature adjustment unit 5, the mold lifting mechanism 60 of the cavity mold is driven by a motor. Therefore, compared with the case where the cavity mold is lifted and lowered by hydraulic pressure, the responsiveness and positional accuracy are higher, and the drying time is shortened. In addition, compared with hydraulic control that requires a motor to be constantly driven to maintain hydraulic pressure, the mold lifting mechanism 60 not only consumes less electricity, but also reduces the amount of cooling water for the working oil.

[0068] (Step S103: Blow molding process) Next, in the blow molding section 6, the container is blow molded.

[0069] First, the blow molding die is closed to house the preform 20, and an air inlet member is inserted into the neck of the preform 20. Then, while lowering the air inlet member, which also serves as a tension rod, blow molding air is introduced into the preform 20 through the air inlet member. As a result, the preform 20 is bulged out and shaped in a manner that is in close contact with the blow molding die, and is blow molded into a container.

[0070] Here, the pair of mold plates 72 of the blow molding section 6 are driven by the motor (75a) of the mold opening and closing section 75 during the opening and closing of the blow molding cavity parting mold 71. Therefore, compared with the case where the mold opening and closing of the blow molding cavity parting mold 71 is performed hydraulically, the responsiveness and positional accuracy are higher, and the drying time is shortened. In addition, compared with hydraulic control that requires a motor to be constantly driven to maintain hydraulic pressure, the mold opening and closing section 75 not only consumes less power, but also reduces the amount of cooling water for the working oil. Moreover, since the piston 73a only needs to move a small amount during mold closing, the amount of working oil can be reduced compared with the case where both the mold opening and closing action and the mold closing action are hydraulic mechanisms.

[0071] On the other hand, the mold closing of the blow molding cavity parting mold 71 is performed by the mold closing section 73, which uses a hydraulic cylinder. By using a hydraulic mechanism for the mold closing of the blow molding cavity parting mold 71, which requires a large load, the cost of the device can be significantly reduced compared to a structure that uses an electric motor for mold closing.

[0072] (Step S104: Container removal process) Once blow molding is complete, the blow molding mold is opened. This allows the container to move from the blow molding section 6.

[0073] Next, the transfer plate 12 rotates by a given angle, and the container is conveyed to the removal section 7. In the removal section 7, the neck of the container is released from the neck mold 22, and the container is removed from the outside of the blow molding apparatus 1.

[0074] This completes one cycle of the blow molding method. Then, by rotating the transfer plate 12 by a given angle, the above-described steps S101 to S104 are repeated. While the blow molding apparatus 1 is running, the manufacturing of four cycle quantities of containers is performed in parallel, each cycle quantity having a time difference of one step.

[0075] Furthermore, in the structure of the blow molding apparatus 1, the standby time for the injection molding process, the temperature adjustment process, the blow molding process, and the container removal process is the same length. Similarly, the conveying time between each process is also the same length.

[0076] This invention is not limited to the above-described embodiments. Various improvements and design changes can be made without departing from the spirit of this invention.

[0077] For example, in the above embodiments, the motors used for each part are not limited to servo motors, and other motors such as stepper motors can also be used.

[0078] Furthermore, the embodiments disclosed herein should be considered illustrative in all respects and not restrictive. The scope of the invention is shown not by the foregoing description but by the scope of the patent claims, and is intended to include the meaning equivalent to the scope of the patent claims and all modifications within that scope.

[0079] Explanation of reference numerals in the attached figures 1: Blow molding device; 3: Injection device; 3c: Drive actuator; 4: Injection molding section; 5: Temperature adjustment section; 6: Blow molding section; 12: Transfer plate; 20: Preform; 21: Injection mold; 22: Neck mold; 31: Mold opening and closing mechanism; 40: Lifting mechanism; 42a, 52a, 75a: Servo motor; 50: Mold closing cylinder; 60: Mold lifting mechanism; 71: Blow molding cavity parting mold; 72: Mold closing plate; 73: Mold closing section; 75: Mold opening and closing section.

Claims

1. A blow molding apparatus, comprising: The injection molding section injects resin material into an injection mold to create a preform with a bottomed cylindrical shape. A temperature adjustment unit, which adjusts the temperature of the preform obtained from the injection molding unit; and The blow molding section blow molds the pre-plasticized preform after temperature adjustment while it is still heated as in injection molding, thereby manufacturing a resin container. The injection molding section has: An injection device that injects the resin material into the injection mold under the control of a first motor; A mold opening and closing mechanism, which opens and closes the injection mold via a second motor; and A hydraulic cylinder is used to close the injection mold after the mold is closed.

2. The blow molding apparatus according to claim 1, wherein, The blow molding apparatus also includes a transfer plate having a neck mold for holding the preform and for transferring the preform to various parts. The injection molding unit also has a transfer plate lifting mechanism, which uses a third motor to move the transfer plate relative to the injection mold in the vertical direction.

3. The blow molding apparatus according to claim 2, wherein, The temperature adjustment unit has a mold lifting mechanism, which moves the temperature adjustment mold relative to the pre-plasticized blank via a fourth motor.

4. The blow molding apparatus according to any one of claims 1 to 3, wherein, The blow molding section has: A pair of blow molding parting dies that define the shape of the container; The parting mold opening and closing section, which is driven by a fifth motor in the opening and closing direction, comprises the blow molding parting mold; and A hydraulic drive unit that closes the blow molding parting mold after the mold is closed.

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