Rod

Abstract

To provide a rod for use in a molding device, which has increased strength, is less prone to breakage, and requires less frequent replacement.SOLUTION: An approximately rod-shaped rod 50 includes: a separator-side tip part 54 that is accommodated in a state of being unconnected to a separator recess 43 formed in a separator 40 accommodated in a die 20 of a molding machine 1; a rear end 56 located on an opposite side to the separator-side tip part 54; and a support shaft 55 that is located between the separator side tip part 54 and the rear end 56, and enables the separator-side tip part 54 and the rear end 56 to rotate in different directions in an axial direction of the die 20. A rod front part 51 on the separator side tip part 54 side of the support shaft 55 has a rectangular cross section parallel to the support shaft 55.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a molding apparatus including a cylindrical die and a core arranged inside the die, movable in the axial direction of the die, and forming a flow path for molten resin between the die and the core, and relates to a rod that enables a separator housed in a die recess formed radially of the die to be moved in the axial direction of the die. [Background technology]

[0002] As shown in FIG. 6 , Patent Document 1 discloses a cylindrical die 200, a core 300 that is disposed inside the die 200 and is movable relative to the die 200 in the direction of the axis Z of the die 200, and forms a flow path for molten resin between the die 200 and the core 300, a die recess 210 that is provided in the die 200 and opens toward the downstream side in the flow direction of the molten resin, and a plurality of separators 400 that are accommodated in the radial direction of the die 200 and are slidable in the direction of the axis Z of the die 200, and a die recess 210 that forms a part of the inner wall of the die recess 210 and is positioned on the core 300 side with respect to the separators 400. The molding device 100 includes a wall portion 220 extending from the core 300 side so that its thickness gradually decreases toward the downstream side in the flow direction of the molten resin, and a separator recess 410 formed on the surface of the separator 400 opposite the core 300 side and having a shape that expands radially outward or follows the radial direction, and a rod 500 that slides the separator 400 in the axial direction, and a slide mechanism 110 that includes an actuator 140, wherein the wall portion 220 is elastically deflectable radially outward when pressed by the molten resin flowing through the flow path.

[0003] The rod 500 is generally rod-shaped and includes a separator-side tip 510 that is housed in the separator recess 410 of the separator 400 without being connected thereto, a rear end 520 that is located on the opposite side to the separator-side tip 510, and a through hole 530 located midway between the separator-side tip 510 and the rear end 520, and is supported by the die 200 by a support shaft 130 provided on the support plate 120 so as to be rotatable at the through hole 530. The separator-side tip 510 of the rod 500 is formed in a hemispherical shape.

[0004] When the rear end 520 of the rod 500 is moved up and down in the axial direction of the die 200 by the slide mechanism 110, the separator side tip 510 of the rod 500 moves in the opposite direction to the rear end 520 via the support shaft 130, and the separator 400 can be moved in the axial direction of the die 200. This makes it possible to change the thickness of the molten resin flowing through the flow path. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6927864 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, the separator side tip 510 of the rod 500 is described as being hemispherical, and the cross-sectional shape in the direction parallel to the support shaft 130 is circular. Note that Patent Document 1 does not describe the cross-sectional shape in the direction parallel to the support shaft 130 of the portion other than the separator side tip 510, but in the rod 500, the cross-section in the direction parallel to the support shaft 130 of the portion other than the separator side tip 510 is generally also circular.

[0007] In the above molding apparatus 100, a force acts on the separator 400 in the outer circumferential direction of the die 200 due to the molten resin, and a similar force also acts on the separator side tip 510 of the rod 500. In addition, in a state in which a force acts on the separator side tip 510 of the rod 500 in the outer circumferential direction of the die 200, it is necessary to move the separator 400 up and down to change the thickness of the molten resin. Therefore, during molding, breakage may occur in the rod 500 between the separator side tip 510 and the through hole 530, especially in a portion with a small cross-sectional area in a direction parallel to the support shaft 130.

[0008] Since breakage of the rod leads to molding defects and it is difficult to determine when the rod has broken, the rod needs to be replaced periodically, but an increase in the frequency of replacement increases the cost of the product. Therefore, there is a demand to increase the strength of the rod and reduce the frequency of rod replacement. [Means for solving the problem]

[0009] In order to solve the above problem, the present invention of claim 1 provides a molding apparatus including a cylindrical die and a core that is arranged inside the die, is movable in the axial direction of the die, and forms a flow path for molten resin between the die and the core. The rod is configured to move a separator housed in a die recess formed in the radial direction of the die, in the axial direction of the die, the rod being approximately rod-shaped and having a separator-side tip portion that is housed without being connected to the separator recess of the separator, a rear end portion located opposite the separator-side tip portion, and a support shaft located intermediate the separator-side tip portion and the rear end portion and allowing the separator-side tip portion and the rear end portion to rotate in the axial direction of the die and in different directions from each other, and the front portion of the rod closer to the separator-side tip portion than the support shaft has a rectangular cross section parallel to the support shaft.

[0010] In the present invention of claim 1, the rod is generally rod-shaped, and includes a separator-side tip that is accommodated in the separator recess of the separator without being connected to the separator-side tip, a rear end located opposite the separator-side tip, and a support shaft located between the separator-side tip and the rear end and enabling the separator-side tip and the rear end to rotate in the axial direction of the die and in different directions from each other, and the front side of the rod closer to the separator-side tip than the support shaft has a rectangular cross section in a direction parallel to the support shaft, so that the cross-sectional area is larger than when the cross section is an arc shape such as a circle. As a result, the strength of the rod is increased, and the frequency of breakage between the separator-side tip and the support shaft during molding can be reduced. Also, the frequency of replacing the rod can be reduced accordingly.

[0011] The present invention of claim 2 is the invention of claim 1, wherein the cross section perpendicular to the support axis of the separator side tip is a convex arc shape toward the separator recess side, the portion of the separator recess close to the die axis is a curved surface consisting of part of the side surface of a cylinder, and the radius of the separator side tip of the rod is smaller than the radius of the curved surface of the separator recess of the separator.

[0012] In the present invention of claim 2, the cross section of the separator-side tip in the direction perpendicular to the support shaft is a convex arc shape toward the separator recess side, the portion of the separator recess close to the axis of the die is a curved surface consisting of a part of the side surface of a cylinder, and the radius of the separator-side tip is smaller than the radius of the curved surface of the separator recess, so that the separator-side tip and the curved surface of the separator recess abut on each other along a line. As a result, the abutment area is larger than when the separator-side tip is made hemispherical and abuts on the curved surface at the back side of the separator recess at a point, so that the force applied to the separator-side tip when abutting on the separator recess is dispersed, and the frequency of breakage of the front part of the rod during molding can be reduced. This also reduces the frequency of rod replacement. Effect of the Invention

[0013] In a molding apparatus including a cylindrical die and a core disposed inside the die, movable in the axial direction of the die, and forming a flow path for molten resin between the die and the core, a rod that allows a separator housed in a die recess formed in the radial direction of the die to move in the axial direction of the die, the rod is substantially rod-shaped, and includes a separator-side tip that is housed without being connected to the separator recess of the separator, a rear end located opposite the separator-side tip, and a support shaft located midway between the separator-side tip and the rear end and that allows the separator-side tip and the rear end to rotate in the axial direction of the die and in different directions from each other, and the rod tip on the separator-side tip side of the support shaft has a rectangular cross section in a direction parallel to the support shaft, so that the cross-sectional area is increased compared to when the cross section is an arc shape such as a circle. As a result, the strength of the rod is increased, so that the frequency of breakage occurring between the separator-side tip and the support shaft during molding can be reduced. Also, the frequency of rod replacement can be reduced accordingly. [Brief description of the drawings]

[0014] [Figure 1] 1 is a cross-sectional view of one side of an axial direction of a die, illustrating a molding apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a perspective view of a rod according to an embodiment of the present invention for use in a molding apparatus. [Diagram 3] FIG. 3 is a top view seen from the direction A in FIG. [Figure 4] FIG. 3 is a side view seen from a direction B in FIG. 2. [Diagram 5] FIG. 3 is a front view seen from a direction C in FIG. [Figure 6] FIG. 1 is a cross-sectional view of a conventional molding device (Patent Document 1). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] A molding apparatus according to an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 5. Fig. 1 is one side of a cross section in the direction of axis Z that illustrates the molding apparatus in a simplified manner. As shown in Fig. 1, the molding apparatus 1 has a cylindrical die 20 and a core 30 disposed inside the die 20. The core 30 is substantially columnar or cylindrical, and is disposed so as to have the same axis Z as the die 20, i.e., coaxially.

[0016] The molding apparatus 1 is disposed so that one end side of the die 20 and the core 30 in the direction of the axis Z is on the upper side, and the other end side is on the lower side. That is, the molding apparatus 1 is disposed so that the axis Z is oriented vertically. However, the orientation of the molding apparatus 1 during use is not limited to this, and for example, the molding apparatus 1 may be disposed so that the axis Z is oriented horizontally.

[0017] Hereinafter, the direction extending along the axis Z of the die 20 and the core 30 will be referred to as the "axial direction." Also, the radial direction of the die 20 and the core 30 will be referred to as the "radial direction." Also, in the drawings, the upper side of the molding apparatus 1, i.e., the upstream direction, is indicated by an arrow UP, the lower side, i.e., the downstream direction, is indicated by an arrow DW, and the radially outward direction is indicated by an arrow KS.

[0018] A flow path 2 for the molten resin is formed between an inner peripheral surface 21 of the die 20 and an outer peripheral surface 31 of the core 30. The molten resin is made to flow through the flow path 2 from one end side to the other end side of the molding device 1, that is, from the upper side to the lower side in Fig. 1, and is molded into a parison P having a predetermined shape.

[0019] In the molding device 1, the core 30 can be moved axially upward or downward relative to the die 20 by a moving mechanism (not shown). A core enlarged diameter section 32 is formed on the lower end side of the outer circumferential surface 31 of the core 30, where the diameter of the core 30 gradually increases toward the end side. Between this core enlarged diameter section 32 and a die enlarged diameter section 22 or an opposing surface 41 of a separator 40 (described later), the width of the flow path 2 changes toward the end side due to the axial movement of the core 30.

[0020] A die recess 23 that opens to an end side is formed in the die 20. Although not shown, the die recess 23 has an annular shape that is continuous in the radial direction of the die 20.

[0021] A plurality of separators 40 (not shown) are arranged in the die recess 23 so as to annularly surround the core 30. A separator recess 43 recessed radially inward (toward the axis Z) is formed in the approximate center of the separator outer circumferential surface 42 of the separator 40.

[0022] The inner side (portion close to axis Z) of separator recess 43 has curved surface 44, which is a cylinder cut in half and has an arc-shaped cross section in the direction of axis Z. Curved surface 44 has a radius of R1. It is also connected to the half of the cylinder and has a prismatic shape that expands toward separator outer peripheral surface 42, that is, its cross section in the axial direction is trapezoidal.

[0023] The molding device 1 has a slide mechanism 10 that corresponds one-to-one with the separator 40. The slide mechanism 10 is a mechanism for sliding the separator 40 in the axial direction. The slide mechanism 10 is composed of a rod 50 and a movement mechanism 11.

[0024] 2 to 5, rod 50 has a generally bar-like shape with support shaft portion 52 located approximately in the center and support shaft portion 52 sandwiched between rod front portion 51 and rod rear portion 53. The tip portion of rod front portion 51 opposite support shaft portion 52 is separator-side tip portion 54 that abuts against and is accommodated in separator recess 43 in a state where it is not connected to separator 40 (unconnected state).

[0025] The support shaft portion 52 is a rectangular parallelepiped, and the support shaft 55 protrudes coaxially from approximately the center of the two opposing faces. The support shaft 55 is a cylinder. Note that the support shaft portion 52 is not limited to a rectangular parallelepiped, and the support shaft 55 does not have to protrude from approximately the center of the two opposing faces as long as it is coaxial. The support shaft 55 enables the rod front portion 51 and the rod rear portion 53 to rotate in different directions.

[0026] 1 and 4, the separator-side tip 54 has an arc shape on the rear side (portion close to the axis Z) of the separator recess 43. The radius of the separator-side tip 54 is R2, and with respect to the radius R1 of the curved surface 44 of the separator recess 43 of the separator 40 described above, the relationship R1>R2 is satisfied.

[0027] 4, the rod front portion 51 has a thickness reducing portion 57 that reduces in thickness and connects to the separator side tip portion 54, a constant thickness portion 58 that has a constant thickness and connects to the thickness reducing portion 57, and a thickness increasing portion 59 that increases in thickness toward the support shaft portion 52. The thickness of the portion connected to the support shaft portion 52 is greater than the diameter of the separator side tip portion 54. As is clear from FIG. 5, the cross section of the rod front portion 51 parallel to the support shaft 55 is a square. However, the cross section of the rod front portion 51 parallel to the support shaft 55 may be rectangular.

[0028] The rod rear side portion 53 is a cylinder. Note that, like the rod front side portion 51, the rod rear side portion 53 may also be a rectangular parallelepiped whose cross section in a direction parallel to the support shaft 55 of the rod front side portion 51 is a square or rectangular parallelepiped.

[0029] A support plate 12 is attached to the die 20, and a support shaft 55 of the rod 50 formed in the support plate 12 is housed therein, so that the rod 50 is rotatably supported at its middle portion by the die 20. A separator-side tip 54 of the rod 50 is housed in contact with the separator recess 43 without being connected to the separator 40 (unconnected state).

[0030] 1, a moving mechanism 11 is attached to the outer periphery of the die 20 in one-to-one correspondence with the rods 50. The moving mechanism 11 includes an actuator 13 having a cylinder 14 and a piston 15 extending from the cylinder 14, and a tip portion of the piston 15 is connected to a rear end portion 56 of a rod rear portion 53 of the rod 50 by a fastening portion 16, which will not be described in detail. When the actuator 13 is driven, the rod front portion 51 of the rod 50 moves in the axial direction of the die 20 in conjunction with the axial movement of the piston 15, and the separator 40 in contact with the separator-side tip portion 54 of the rod 50 can be slid in the axial direction.

[0031] As described above in detail, according to this embodiment, the following effects can be obtained. (1) The rod front portion 51, which is closer to the separator-side tip portion 54 than the support shaft portion 52, has a square cross section parallel to the support shaft 55, and therefore has a larger cross-sectional area than when the cross section is an arc shape such as a circle. As a result, the mechanical strength of the rod front portion 51 is increased, and the frequency with which the rod front portion 51 breaks during molding can be reduced. This also reduces the frequency with which the rod needs to be replaced.

[0032] (2) Since the radius R1 of the curved surface 44 on the rear side of the separator recess 43 is larger than the radius R2 of the separator-side tip 54 of the rod 50, the separator-side tip 54 and the curved surface on the rear side of the separator recess 43 abut on each other along a line. As a result, the abutment area is increased compared to when the separator-side tip 54 is made hemispherical and abuts on the curved surface on the rear side of the separator recess at a point, so that the force applied to the separator-side tip 54 when abutting on the separator recess 43 is dispersed, and the frequency of breakage of the rod front portion 51 during molding can be reduced. This also reduces the frequency of rod replacement.

[0033] (3) The rod front portion 51 has a thickness reducing portion 57 connected to the separator side tip portion 54 and having a decreasing thickness, and a thickness constant portion 58 connected to the thickness reducing portion 57 and having a constant thickness, so that when the die 20 slides up and down in the axial direction of the die 20, the rod front portion 51 of the rod 50 can be prevented from contacting the separator recess 43 at a portion other than the separator side tip portion 54 without increasing the expansion toward the separator outer peripheral surface 42 of the rectangular column shape that expands toward the separator outer peripheral surface 42 connected to the half-cylinder curved surface 44 at the back side of the separator recess 43. As a result, the manufacturing cost of the separator 40 can be reduced.

[0034] The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the object of the present invention.

[0035] For example, in the above embodiment, the rod front portion 51 is formed with the plate thickness reducing portion 57 connected to the separator side tip portion 54 and having a decreasing thickness, the plate thickness constant portion 58 connected to the plate thickness reducing portion 57 and having a constant thickness, and the plate thickness increasing portion 59 whose plate thickness increases toward the support shaft portion 52, but the plate thickness reducing portion 57 and the plate thickness increasing portion 59 may be connected in a gentle arc shape without forming the plate thickness constant portion 58. Also, the separator side tip portion 54 and the support shaft portion 52 may be connected by the plate thickness constant portion 58. [Explanation of symbols]

[0036] 1 Molding equipment 20 Die 23 Die recess 30 cores 40 Separator 42 Separator outer surface 43 Separator recess 50 Rod 51 Front side of rod 52 Support shaft 53 Rear side of rod 54 Separator side tip 55 Spindle 56 Rear end 57 Reduced thickness section 58 Constant thickness section 59 Increased thickness

Claims

1. In a molding apparatus including a cylindrical die and a core disposed inside the die and movable in an axial direction of the die, the core forming a flow path for a molten resin between the die and the core, a rod is provided for moving a separator housed in a die recess formed in a radial direction of the die in the axial direction of the die, the rod has a generally bar-like shape and includes a separator-side front end portion that is accommodated in a separator recess formed in the separator without being connected thereto, a rear end portion that is positioned opposite the separator-side front end portion, and a support shaft that is positioned midway between the separator-side front end portion and the rear end portion and that enables the separator-side front end portion and the rear end portion to rotate in the axial direction of the die and in directions different from each other; A rod characterized in that a front portion of the rod, which is located closer to the separator than the support shaft, has a rectangular cross section parallel to the support shaft.

2. a cross section of the separator-side tip portion in a direction perpendicular to the support shaft has an arc shape that is convex toward the separator recessed portion, a portion of the separator recess close to the axis of the die is a curved surface formed from a part of a side surface of a cylinder, The rod according to claim 1 , wherein a radius of the separator side tip of the rod is smaller than a radius of the curved surface of the separator recess of the separator.

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