Vertical injection molding apparatus

Abstract

To provide a turntable type vertical injection molding apparatus capable of reducing height while ensuring sufficiently large injection capacity.SOLUTION: A vertical injection molding apparatus (10) comprises: a mold clamping device (20) with a vertical mold clamping axis (20a); a turntable (23) that places a lower mold (13) and moves between a mold clamping position (18) and a product takeout position (17); and an injection device (50) with a vertical injection axis(50a). The injection device (50) has: a left and right pair of a first heating cylinder (53L) and a second heating cylinder (53R); and a Y-shaped adapter (80) connected below the first heating cylinder (53L) and the second heating cylinder (53R), combining flows of a resin material from the first heating cylinder (53L) and the resin material from the second heating cylinder (53R), and injecting it from one nozzle (53a).SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an improved technology for a vertical injection molding apparatus. [Background technology]

[0002] 2. Description of the Related Art Injection molding apparatuses that inject a resin material into a mold to obtain a resin molded product (hereinafter referred to as a product) are widely used. Injection molding machines are classified into horizontal injection molding machines and vertical injection molding machines. As a vertical injection molding machine, a turntable type vertical injection molding machine having a turntable is known (for example, see Patent Document 1 (FIG. 1)).

[0003] Patent Document 1 will be explained with reference to the following figure. FIG. 8 is a side view of a conventional turntable type vertical injection molding apparatus. 8, this vertical injection molding apparatus 101 has a turntable 103 on a bed 102, and a mold clamping device 104 is provided on the bed 102 so as to sandwich the turntable 103. An injection device 105 is provided on the mold clamping device 104.

[0004] A mold clamping axis 106 of the mold clamping device 104 and an injection axis 107 of the injection device 105 are both vertical and share a common axis. In the turntable 103, a portion overlapping with the mold clamping shaft 106 becomes a mold clamping position 109, and a portion symmetrical with respect to the rotation shaft 111 becomes a product removal position 112 where a product is removed.

[0005] An upper die 113 and a first lower die 114 are disposed along the die clamping shaft 106. At this time, a second lower die 115 is disposed at the product removal position 112. An upper die 113 is mated with this first lower die 114 and clamped by a clamping device 104 , and a resin material is injected from a heating barrel 116 of an injection device 105 .

[0006] Once the resin material has solidified, the upper die 113 is raised, the turntable 103 is rotated 180°, the first lower die 114 moves to the product removal position 112, and the product is removed. Due to the rotation of the turntable 103, the second lower die 115 moves to the mold clamping position 109. The next injection molding is performed using this second lower die 115 and the upper die 113.

[0007] The turntable method has the advantage of increasing production efficiency because the injection of resin material and the removal of the product are carried out simultaneously in parallel. However, as the size of the product increases, the size of the injection device 105 also increases. Specifically, the outer diameter of the heating barrel 116 increases, and the axial length of the heating barrel 116 also increases. When the axial length increases, the height H1 of the vertical injection molding apparatus 101 increases.

[0008] If the ceiling of the building in which the vertical injection molding apparatus 101 is installed is low, the vertical injection molding apparatus 101 with a large height H1 cannot be installed. In this case, a small-height injection molding device is required. Various turntable-type small-height injection molding devices have been put to practical use (see, for example, Patent Document 2 (FIG. 4)).

[0009] Patent Document 2 will be explained with reference to the following figure. FIG. 9 is a front view of another conventional turntable type injection molding apparatus. 9, this injection molding apparatus 121 includes a turntable 123 on a bed 122, and a mold clamping device 124 is provided on the bed 122 so as to sandwich the turntable 123. An injection device 125 is provided next to the mold clamping device 124.

[0010] The clamping shaft 126 of the clamping unit 124 is vertical, and the injection shaft 127 of the injection unit 125 is horizontal. Even if the shaft length of the injection unit 125 increases with the increase in size of the product, the height H2 of the injection molding unit 121 remains almost constant and can be kept small. Therefore, Patent Document 2 provides an injection molding apparatus 121 that can be installed in a building with a low ceiling even when the product is large.

[0011] However, the injection molding apparatus 121 of Patent Document 2 has the following drawbacks. As the size of the product increases, the horizontal length L2 of the injection molding apparatus 121 increases. When the horizontal length L2 increases, the so-called floor area increases. When the floor area increases, it becomes impossible to install the required number of injection molding apparatuses 121 in a building with a certain floor area. When the number of injection molding apparatuses 121 decreases, productivity decreases.

[0012] Vertical injection molding apparatus 101 shown in FIG. 8 has a sufficiently small horizontal length L1, so that a required number of apparatuses can be easily installed in a building with a certain floor area. Therefore, there is a demand for a turntable type vertical injection molding apparatus that can reduce the height H1 while ensuring a sufficiently large injection volume. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] Patent No. 5781675 [Patent Document 2] Japanese Patent Application Publication No. 8-174594 Summary of the Invention [Problem to be solved by the invention]

[0014] An object of the present invention is to provide a turntable-type vertical injection molding apparatus equipped with a vertical injection unit that can reduce the height while ensuring a sufficiently large injection volume. [Means for solving the problem]

[0015] The inventors of the present invention have tried various methods to reduce the height of a turntable type vertical injection molding machine. In the course of these attempts, they discovered that by replacing one heater barrel with two heater barrels, it is possible to reduce the height of the injection molding machine while maintaining the injection volume. The process of this discovery is explained in the following diagram.

[0016] 1(a) has a sufficiently large injection volume. The axial length, i.e., height, of the heating barrel 128 is Ha. Consider replacing such a heater barrel 128 with two heater barrels.

[0017] 1(b), the first heating barrel 53L is replaced by the second heating barrel 53R. The first heating barrel 53L has a smaller diameter and length because the injection volume is half that of the heating barrel 128. The same is true for the second heating barrel 53R.

[0018] However, it is necessary to connect a joining adapter to the outlet of the first heating barrel 53L and the outlet of the second heating barrel 53R. A typical adapter is a T-shaped adapter 130. The T-shaped adapter 130 allows the resin material injected from the first heating barrel 53L and the resin material injected from the second heating barrel 53R to be injected together from the nozzle.

[0019] However, the T-shaped adapter 130 has the following advantages and disadvantages. The T-shaped adapter 130 has the advantage that the height dimension hb is small. On the other hand, there is a drawback in that the resin material flowing through the first horizontal flow path 131 and the resin material flowing through the second horizontal flow path 132 directly collide from the left and right, causing disturbance in the flow of the resin material.

[0020] Considering the flow of the resin material, it is desirable for the surfaces of the first horizontal flow passage 131 and the second horizontal flow passage 132 to be smooth. However, the T-shaped adapter 130 has a structure that makes it difficult to apply honing processing.

[0021] Honing is possible if the T-shaped adapter 130 is divided, but it needs to be divided into at least two places, and preferably four places, and the divided parts need to be joined with flanges or screws. As a result, the structure of the T-shaped adapter 130 becomes complicated.

[0022] In order to overcome the above-mentioned shortcomings, the present inventors have come up with the idea shown in FIG. As shown in FIG. 1(c), the adapter was a Y-shaped adapter 80. However, the Y-shaped adapter 80 has the following advantages and disadvantages.

[0023] A disadvantage is that the height hc of the Y-shaped adapter 80 is greater than the height hb of the T-shaped adapter 130 .

[0024] As a result, as shown in Figures 1(a) to (c), the height Hc of the Y-shaped adapter 80 plus the first heated barrel 53L is greater than the height Hb of the T-shaped adapter 130 plus the first heated barrel 53L, but is sufficiently smaller than the height Ha of the heated barrel 128.

[0025] The advantages of the Y-shaped adapter 80 shown in FIG. 1(c) will be described in detail with reference to FIGS. 2(a) and 2(b). FIG. 2(a) is a cross-sectional view of a Y-shaped adapter according to the present invention, and FIG. 2(b) is a diagram illustrating the honing process.

[0026] 2(a), the Y-shaped adapter 80 is a member having two inlets and one outlet, and is made up of a V-shaped portion 81 connected to the tip (lower end) of the first heating barrel 53L and the tip (lower end) of the second heating barrel 53R with bolts or the like, and an I-shaped portion 82 hanging down from the V-shaped portion 81. The V-shaped portion 81 and the I-shaped portion 82 form a Y shape.

[0027] The V-shaped portion 81 and the I-shaped portion 82 are separable and are integrated together by screw connection or flange connection. In addition to the threaded portion 83, the I-shaped portion 82 is formed with a nozzle 53a.

[0028] The V-shaped portion 81 has a first downward flow passage 84 connected to the first heating barrel 53L, a first diagonal flow passage 85 extending diagonally from the lower end of the first downward flow passage 84, a second downward flow passage 86 connected to the second heating barrel 53R, and a second diagonal flow passage 87 extending diagonally from the lower end of the second downward flow passage 86.

[0029] The inclination angle θ of the first oblique flow channel 85 with respect to the vertical axis is preferably 45°. If the inclination angle θ is much greater than 45°, collisions between the resin materials may occur, whereas if the inclination angle θ is much less than 45°, the height dimension increases. As long as collisions between the resin materials are avoided and the increase in height dimension falls within an allowable range, the inclination angle θ may be set to a value other than 45°. The same applies to the second oblique flow passage 87.

[0030] 2(b), the first downward flow passage 84 and the second downward flow passage 86 are open at the top, so that a rotary grindstone 89 can be inserted from above. As a result, the surfaces of the first downward flow passage 84 and the second downward flow passage 86 are honed and made smooth.

[0031] The downward extension line 88 of the first diagonal flow passage 85 and the downward extension line 88 of the second diagonal flow passage 87 do not interfere with the wall of the V-shaped portion 81. As a result, the grindstone 89 can be inserted from below.

[0032] 2(a) and 2(b), the resin material flowing through the first diagonal flow passage 85 and the resin material flowing through the second diagonal flow passage do not collide directly with each other, and the two flows merge smoothly. In other words, this has the advantage that the flow of the resin material is not disturbed. A second advantage is that the first diagonal flow passage 85 and the second diagonal flow passage 87 can be easily subjected to finishing processing such as honing.

[0033] The invention completed based on the above findings is as follows. The invention according to claim 1 is a vertical injection molding apparatus including a clamping device having a vertical clamping axis that clamps an upper mold to a lower mold, a turntable on which the lower mold is placed and which moves between a clamping position and a product removal position, and an injection device having a vertical injection axis that is disposed above the clamping device and that injects a resin material into a mold consisting of the lower mold and the upper mold, The injection device is characterized by having a pair of first and second heating barrels, one on the left and one on the right, and a Y-shaped adapter connected below the first and second heating barrels to merge the resin material from the first heating barrel and the resin material from the second heating barrel and inject it from a single nozzle.

[0034] The invention according to claim 2 is the vertical injection molding apparatus according to claim 1, the Y-shaped adapter includes a V-shaped portion connected to the bottom of the first heating barrel and the second heating barrel, and an I-shaped portion detachably connected to the V-shaped portion and including the nozzle; The V-shaped portion has a first diagonal flow path and a second diagonal flow path, and is characterized in that downward extension lines extending downward from the first diagonal flow path and the second diagonal flow path do not interfere with the flesh of the V-shaped portion. Vertical injection molding equipment.

[0035] The invention according to claim 3 is the vertical injection molding apparatus according to claim 1 or 2, The mold clamping device includes a pressure-receiving platen fixed to a bed, a traction platen arranged below the pressure-receiving platen and raised and lowered by a half nut position adjustment means, a movable platen arranged above the pressure-receiving platen and raised and lowered by a mold opening and closing means, and a tie bar lowered from the movable platen and passing through the pressure-receiving platen and the traction platen, and clamps the mold arranged between the pressure-receiving platen and the movable platen, The present invention is characterized in that an engagement portion is provided at the lower end of the tie bar, and a half nut that engages with the engagement portion is provided below the traction plate. Effect of the Invention

[0036] In the invention according to claim 1, in a turntable type vertical injection molding device, the heating barrel extending upward is composed of a pair of first and second heating barrels on the left and right. By dividing one heating barrel into two, the height of the first and second heating barrels can be significantly reduced. The injection volume is the sum of the injection volume of the first heating barrel and the injection volume of the second heating barrel, and a sufficient size can be ensured.

[0037] In addition, the resin material from the first heating barrel and the resin material from the second heating barrel are joined together using a Y-shaped adapter and then injected from a single nozzle, which prevents the resin materials from colliding with each other and enables smooth injection. As a result, according to claim 1, a turntable type vertical injection molding apparatus is provided that is equipped with a vertical injection unit that can reduce the height while ensuring a sufficiently large injection volume.

[0038] In the invention according to claim 2, the V-shaped portion, which is the main part of the Y-shaped adapter, is structured so that the downward extension line of the first diagonal flow path and the downward extension line of the second diagonal flow path do not interfere with the wall of the V-shaped portion, so that the rotary grinding wheel can be easily inserted into the first diagonal flow path and the second diagonal flow path, and the surfaces of the first diagonal flow path and the second diagonal flow path can be made smooth. If the surfaces are smooth, the flow of the resin material becomes smooth.

[0039] In the invention according to claim 3, a half nut is adopted. If the half nut method is used, the height can be made smaller than that of the vertical injection molding apparatus 101 shown in FIG. In addition to configuring the heating barrel as a pair of a first heating barrel and a second heating barrel on the left and right sides, the use of half nuts makes it possible to further reduce the height of the turntable-type vertical injection molding device. [Brief description of the drawings]

[0040] [Figure 1] 1(a) to 1(c) are diagrams for explaining how the present invention was completed. [Diagram 2] FIG. 2(a) is a cross-sectional view of a Y-shaped adapter according to the present invention, and FIG. 2(b) is a diagram illustrating honing processing. [Diagram 3] 1 is a diagram showing the overall configuration of a vertical injection molding apparatus according to the present invention; [Figure 4] FIG. 4 is a view taken along line 4-4 in FIG. [Diagram 5] 1 is a diagram illustrating the operation of a vertical injection molding apparatus. [Figure 6] 1A and 1B are diagrams for explaining the operation of an injection unit which is one element of a vertical injection molding machine. [Figure 7] FIG. 13(a) is a diagram showing a modified example of the Y-shaped adapter, and FIG. 13(b) is a diagram explaining the function of the check valve. [Figure 8] FIG. 1 is a side view of a conventional turntable type vertical injection molding apparatus. [Figure 9] FIG. 1 is a front view of another conventional turntable type injection molding apparatus. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0041] An embodiment of the present invention will be described below with reference to the accompanying drawings. In a cylinder, "extension" means that the piston rod is advanced to extend the overall length of the cylinder, and "contraction" means that the piston rod is retreated to shorten the overall length of the cylinder. EXAMPLES

[0042] As shown in FIG. 3, the vertical injection molding apparatus 10 is an apparatus whose main elements are a clamping unit 20 having a vertical clamping axis 20a that clamps a mold 12 consisting of a lower mold 13 and an upper mold 14, and an injection unit 50 having a vertical injection axis 50a that is disposed above and vertically to the clamping unit 20.

[0043] The mold clamping device 20 includes a bed 21 fixed to the floor (or machine base) 16, a pressure platen 22 fixed to the bed 21, a turntable 23 placed on the pressure platen 22, a traction platen 79 arranged below the pressure platen 22 and raised and lowered by a half nut position adjustment means 24 provided on the pressure platen 22, a half nut 26 arranged below the traction platen 79 including a mold clamping cylinder 33, a movable platen 28 arranged above the pressure platen 22 and raised and lowered by a mold opening and closing means 27 provided on the pressure platen 22, a tie bar 31 lowered from the movable platen 28 and passing through the pressure platen 22 and the traction platen 79, and a pump motor unit 32 that supplies pressurized oil to the half nut position adjustment means 24, the mold clamping cylinder 33, the mold opening and closing means 27, etc.

[0044] The half nut position adjusting means 24 is preferably a half nut position adjusting hydraulic cylinder 24A. Similarly, the mold clamping means 25 is preferably a mold clamping cylinder 33, and the mold opening / closing means 27 is preferably a mold opening / closing hydraulic cylinder 27A.

[0045] The pressure-receiving platen 22 can be removed from the bed 21 by loosening bolts, etc. Therefore, "fixed" in the present invention includes a form in which it is detachably connected in addition to a form in which it is completely fixed. Furthermore, the half nut position adjusting means 24 and the mold opening and closing means 27 may be provided on the bed 21.

[0046] The mold clamping means 25 has, for example, a mold clamping cylinder 33 that opens upward. A piston portion 34 that extends downward from the pressure receiving platen 22 is housed in this mold clamping cylinder 33. An oil pressure chamber 35 is formed between the mold clamping cylinder 33 and the piston portion 34. When pressure oil is supplied to the oil pressure chamber 35, the traction platen 79 is lowered.

[0047] The tie bar 31 is provided at its lower end with an engagement portion 36. The engagement portion 36 is, for example, a sawtooth portion. Hereinafter, the engagement portion 36 will be read as the sawtooth portion 36. The half nuts 26 are split nuts that engage (mesh) with the sawtooth portion 36 serving as an engagement portion. The half nuts 26 are opened and closed by a half nut opening and closing means 37 provided on the traction board 79. The half nut opening and closing means 37 is preferably a half nut opening and closing hydraulic cylinder 37A.

[0048] The sawtooth portion 36 preferably has teeth arranged at equal intervals, like the joints of a bamboo. The teeth may be of any of rectangular, trapezoidal, and triangular cross sections. The half nuts 26 are provided with corresponding teeth.

[0049] The tie bar 31 and half nut 26 are made of strong, hard steel. To ensure smooth contact between the steel, grease lubrication is applied between the serrations 36 and the half nut 26. Grease is applied to the outer circumferential surface of the tie bar 31 at a position higher than the serrations 36. The grease flows down and reaches the serrations 36. Grease application can be automatic or manual.

[0050] Preferably, a half-nut operation monitoring mechanism 38 for monitoring the operation of the half-nut 26 is provided near the half-nut 26. However, the half-nut operation monitoring mechanism 38 may be omitted, provided that the positions of the mold opening / closing means 27 and the half-nut position adjusting means 24 can be precisely controlled.

[0051] The half nut operation monitoring mechanism 38 can be any type of sensor, such as a proximity switch or limit switch. Among these, a proximity switch is a non-contact sensor that determines "object present" when the mating metal approaches within a certain distance and "object not present" when the mating metal is away beyond the certain distance. The half nut 26 is wet with waste grease, but a non-contact sensor does not cause false detection. In addition, it is inexpensive. Therefore, a proximity switch is recommended.

[0052] Preferably, a tray 41 for receiving the waste grease is disposed under the half nuts 26 and on the floor 16. The tray 41 is a dish-shaped container. The tray 41 is pulled out periodically or whenever necessary, and accumulated waste grease is disposed of, thereby preventing the floor 16 from becoming dirty.

[0053] Preferably, the bed 21 is surrounded by a cover 42. This cover 42 serves as a safety cover. Surrounding the bed 21 with the cover 42 improves the appearance of the mold clamping device 20. However, the cover 42 is not essential because it can be replaced with a safety fence or the like.

[0054] The injection device 50 comprises an injection device moving means 51 erected on a movable platen 28, an injection table 52 supported by the injection device moving means 51, a first heating barrel 53L and a second heating barrel 53R supported by the injection table 52 and extending downward, a Y-shaped adapter 80 connected to their ends (the lower end in the figure), an injection means 54 provided on the injection table 52 and having a piston rod extending upward, a first screw drive table 55L and a second screw drive table 55R supported by the injection means 54, a first screw rotation mechanism 56L and a second screw rotation mechanism 56R supported by the first screw drive table 55L and the second screw drive table 55R, and a first screw 57L and a second screw 57R extending downward from the first screw rotation mechanism 56L and the second screw rotation mechanism 56R and entering the first heating barrel 53L and the second heating barrel 53R.

[0055] For convenience, the longitudinal central axis of the first heating barrel 53L and the second heating barrel 53R is set as the injection axis 50a. The Y-shaped adapter 80 functions to join the resin material from the first heating barrel 53L and the resin material from the second heating barrel 53R and eject the combined material from one nozzle 53a.

[0056] The first screw rotation mechanism 56L and the second screw rotation mechanism 56R are, for example, hydraulic motors.

[0057] The injection device moving means 51 is preferably an injection device moving hydraulic cylinder 51A, and the injection means 54 is preferably an injection cylinder 54A.

[0058] More preferably, a purging cover 64 that surrounds the first heating barrel 53L and the second heating barrel 53R is provided on the movable platen 28. In addition, an upper die ejector 60 is provided on the movable platen 28. This upper die ejector 60 is made up of an ejector pin 61 that extends to the upper die 14 and a pin moving means 62 that moves this ejector pin 61, and plays a role in pushing down the runners remaining in the upper die 14. The pin moving means 62 is preferably a pin moving hydraulic cylinder 62A, but it may also be an electric cylinder.

[0059] FIG. 4 is a view taken along line 4-4 in FIG. 4, the tie bars 31 are disposed at the vertices of a triangle. One of the tie bars 31 constitutes the rotation center of the turntable 23. At the product removal position 17, the product is removed from the lower die 13. The empty lower die 13 is moved to the die clamping position 18 by rotating the turntable 23 by 180°. Since the product removal operation and the mold clamping operation can be performed in parallel, the use of the turntable 23 can increase productivity.

[0060] 3, the half nuts 26 are opened and separated from the sawtooth portion 36. Next, the mold opening and closing means 27 is extended to lift the movable platen 28. As the movable platen 28 lifts, the upper mold 14 is separated from the lower mold 13 and the tie bars 31 are lifted. Furthermore, in the injection device 50, the injection device moving means 51 is extended to raise the injection table 52. As the injection table 52 rises, the first heating barrel 53L and the second heating barrel 53R rise.

[0061] The above results are shown in Figure 5. 5, which shows the maximum mold opening state, the lower end 31a of the tie bar 31 rises up to within the traction plate 79. As a result, it is possible to sufficiently shorten the tie bar 31. If the tie bar 31 is short, it becomes lighter and material can be saved. That is, in the conventional technology, a structure in which the lower end portion 31a of the tie bar 31 always protrudes outside the traction plate 79 is preferred. In contrast to this, with the structure shown in FIG.

[0062] When the tie bars 31 are shortened, the height of the mold clamping unit 20 is reduced. When the height of the mold clamping unit 20 is reduced, the height of the vertical injection molding apparatus 10 is reduced. In other words, by changing one heater barrel to two, the first heater barrel 56L and the second heater barrel 56R, the height of the injection device 50 is reduced, and by shortening the tie bars 31, the height of the clamping device 20 is reduced, and together, the height of the vertical injection molding device 10 becomes increasingly smaller.

[0063] In addition, the first heating barrel 53L and the second heating barrel 53R may be raised to perform a purging operation to discharge the accumulated resin material. This purging operation is also called a waste shot process. In the waste shot process, the resin material is ejected from the nozzle 53a, but the purging cover 64 prevents the resin material from scattering. The worker opens the purging cover 64 at any time or as needed to remove the accumulated resin material. According to the present invention, the purging cover 64 surrounding the nozzle 53 a can be easily disposed on the movable platen 28 .

[0064] In the vertical injection molding apparatus 10, the operation of the mold clamping device 20 and the operation of the injection device 50 are carried out in parallel. First, the operation of the mold clamping device 20 will be described. 5, the mold opening / closing means 27 is contracted to lower the movable platen 28, the upper mold 14, and the tie bars 31. When the upper mold 14 comes into contact with the lower mold 13, the lowering of the tie bars 31 and the like is completed.

[0065] There is a phase shift between the sawtooth portion 36 and the half nut 26. To make this phase zero, the traction disk 79 is slightly raised and lowered by the half nut position adjustment means 24. After the adjustment is complete, the half nut opening and closing means 37 is extended to engage the half nut 26 with the sawtooth portion 36. In the unlikely event that there is a misalignment, this is detected by the half-nut operation monitoring mechanism 38. If there is a misalignment, the injection molding operation is stopped and appropriate measures are taken.

[0066] If no misalignment is detected, pressure oil is supplied to the oil pressure chamber 35 of the clamping cylinder 33 in Fig. 3. Then, the traction platen 79 is lowered, the tie bars 31 are pulled down, and the movable platen 28 is lowered. In this manner, the mold 12 is clamped.

[0067] Next, the operation of the injection device 50 will be described with reference to FIGS. In Fig. 5, the first screw 57L and the second screw 57R are rotated in a predetermined direction at a predetermined speed by the first screw rotation mechanism 56L and the second screw rotation mechanism 56R. The resin material is supplied to the first heating barrel 53L and the second heating barrel 53R via a hopper 65. The resin material descends through the grooves of the first screw 57L and the grooves of the second screw 57R. The resin material is heated and kneaded to become plastic.

[0068] The resin material accumulates under the first screw 57L and the second screw 57R in the first heating barrel 53L and the second heating barrel 53R. The reaction force from this accumulation causes the first screw 57L and the second screw 57R to gradually rise. The value obtained by multiplying the cross-sectional area of ​​the first screw 57L and the second screw 57R by the movement amount of the screw becomes the measurement value. When this measurement value reaches a predetermined value, the plasticization and measurement process is completed.

[0069] FIG. 6(a) is a diagram showing the state when the plasticizing and measuring steps are completed, and in FIG. 6(a), the injection device moving means 51 is contracted. As shown in Fig. 6(b), the nozzle 53a comes into contact with a predetermined position of the upper mold 14. Next, the injection means 54 is contracted to advance (lower) the first screw 57L and the second screw 57R. The resin material is injected into the upper mold 14 by the advancing first screw 57L and second screw 57R.

[0070] In addition, since the bed 21 is surrounded by the cover 42, the appearance of the mold clamping device 20 can be improved. On the other hand, it becomes difficult to visually inspect the half nuts 26. In the present invention, the operation of the half nuts 26 is monitored by the half nut operation monitoring mechanism 38, so visual inspection is not necessary and stable operation of the mold clamping device 20 is maintained.

[0071] Furthermore, the mold clamping device 20 and the injection device 50 arranged vertically above the movable platen 28 constitute the vertical injection molding device 10. If the half nuts 26 are located on the movable platen 28 in the mold clamping unit 20, the injection unit 50 (particularly the first heating barrel 53L and the second heating barrel 53R) will interfere with the half nuts 26, making it difficult to arrange the injection unit 50 on the movable platen 28. If the injection unit 50 is forcibly arranged on the movable platen 28, the structure around the movable platen 28 will become complicated. In this regard, according to the present invention, since the top of the movable platen 28 is open, the injection unit 50 can be easily arranged on the movable platen 28. In addition to the injection unit 50, the purging cover 42, the upper die ejector 60, etc. can be arranged on the movable platen 28.

[0072] An improved version of the Y-shaped adapter 80 described with reference to FIGS. 2(a) and 2(b) will now be described with reference to FIGS. 7(a) and 7(b). As shown in FIG. 7(a), the Y-shaped adapter 80 includes a needle 91 that closes the nozzle 53a, and a valve opening / closing hydraulic cylinder 92 provided in the V-shaped portion 81 for raising and lowering the needle 91.

[0073] Injection molding involves the following steps, in that order: an injection process in which resin material is injected into a mold cavity; a pressure holding process in which back pressure is applied to the injected resin material; and a metering process in which the first screw 57L and the second screw 57R are rotated and retracted to meter the resin material. During the metering process, the nozzle 53a is closed by the needle 91. At the start of the injection process, the needle 91 is raised, the nozzle 53a is opened, and injection is performed. The needle 91 remains raised even during the pressure holding step. Once pressure maintenance is complete, the needle 91 is lowered to close the nozzle 53a.

[0074] The stroke of the needle 91 (the distance traveled when opening and closing) may be about 1.0 to 2.0 times the outer diameter of the needle 91. If it is about this size, the valve opening / closing hydraulic cylinder 92 will not be large.

[0075] Preferably, a first check valve 93L is interposed between the first heating barrel 53L and the V-shaped portion 81, and a second check valve 93R is interposed between the second heating barrel 53R and the V-shaped portion 81.

[0076] As shown in Fig. 7(b), the first check valve 93L comprises a cylindrical valve box 94, an upper perforated plate 95 screwed or otherwise fitted into the upper opening of the cylindrical valve box 94, a lower perforated plate 96 screwed or otherwise fitted into the lower opening of the valve box 94, and a ball 97 housed in the valve box 94 so as to be movable up and down. The upper perforated plate 95 has a hole 95a in the center. In addition to the central hole 96a, the lower perforated plate 96 has sub-holes 96b surrounding the hole 96a.

[0077] The ball 97 moves up and down within the valve body 94 according to the pressure difference between above and below the ball 97. When the pressure below the ball 97 is greater, the ball 97 rises and closes the hole 95a, preventing the backflow of the resin material. If the pressure above the ball 97 becomes greater, the ball 97 will move down and allow the forward flow. Even if the ball 97 moves down to its maximum extent and blocks the hole 96a, the resin material will flow through the sub-hole 96b, so the forward flow will be maintained. The same applies to the second check valve 93R.

[0078] For some reason, the resin material may flow from the first diagonal flow path 85 to the second diagonal flow path 87. When this happens, the second check valve 93R is closed to prevent backflow. Similarly, the resin material may flow from the second diagonal flow path 87 to the first diagonal flow path 95. When this happens, the first check valve 93L is closed to prevent backflow.

[0079] Although the first screw rotation mechanism 56L and the second screw rotation mechanism 56R are hydraulic motors, they may be electric motors or electric motors with reducers.

[0080] Further, the engaging portion 36 may be a rough surface, a step, or a recess formed on the outer periphery of the tie bar 31, other than the sawtooth portion, and is not limited to a sawtooth shape. [Industrial Applicability]

[0081] The present invention is suitable for a vertical injection molding apparatus that includes a mold clamping unit with a vertical mold clamping axis and an injection unit that is disposed vertically above the mold clamping unit. [Explanation of symbols]

[0082] 10...vertical injection molding apparatus, 12...mold, 13...lower mold, 14...upper mold, 17...product removal position, 18...mold clamping position, 20...mold clamping device, 20a...mold clamping shaft, 21...bed, 22...pressure receiving platen, 23...turntable, 24...half nut position adjustment means, 25...mold clamping means, 26...half nut, 27...mold opening and closing means, 28...movable platen, 31...tie bar, 31a...lower end of tie bar, 36...engagement portion (sawtooth portion), 50...injection device, 50a...injection shaft, 53a...nozzle, 53L...first heating barrel, 53R...second heating barrel, 79...traction platen, 80...Y-shaped adapter, 81...V-shaped portion, 83...I-shaped portion, 85...first diagonal flow path, 87...second diagonal flow path, 88...downward extension line.

Claims

1. A vertical injection molding apparatus comprising: a clamping device having a vertical clamping axis for clamping an upper mold to a lower mold; a turntable on which the lower mold is placed and which moves between a clamping position and a product removal position; and an injection device having a vertical injection axis, which is disposed above the clamping device and which injects a resin material into a mold consisting of the lower mold and the upper mold; The injection device is a vertical injection molding device characterized in that it has a pair of first and second heater barrels, one on the left and one on the right, and a Y-shaped adapter connected below the first and second heater barrels to merge the resin material from the first heater barrel and the resin material from the second heater barrel and inject them from a single nozzle.

2. The vertical injection molding apparatus according to claim 1, the Y-shaped adapter includes a V-shaped portion connected to the bottom of the first heating barrel and the second heating barrel, and an I-shaped portion detachably connected to the V-shaped portion and including the nozzle; The V-shaped portion has a first diagonal flow path and a second diagonal flow path, and downward extension lines extending downward from the first diagonal flow path and the second diagonal flow path do not interfere with the wall of the V-shaped portion.

3. The vertical injection molding apparatus according to claim 1 or 2, The mold clamping device includes a pressure-receiving platen fixed to a bed, a traction platen arranged below the pressure-receiving platen and raised and lowered by a half nut position adjustment means, a movable platen arranged above the pressure-receiving platen and raised and lowered by a mold opening and closing means, and a tie bar lowered from the movable platen and passing through the pressure-receiving platen and the traction platen, and clamps the mold arranged between the pressure-receiving platen and the movable platen, A vertical injection molding apparatus, characterized in that an engaging portion is provided at a lower end of the tie bar, and a half nut that engages with the engaging portion is provided below the traction plate.

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