Steel bar body forming die and method for manufacturing steel bar body using the same

Abstract

The present invention provides a reinforcing bar body forming mold capable of easily and inexpensively manufacturing a reinforcing bar body having sufficient strength, and a manufacturing method using the same. In the reinforcing bar body forming mold, a main flow channel (F1) through which a thermoplastic resin material (Rt) output from an extruder (2) passes is formed in a central portion of a main body, and a first sub-flow channel (F2) through which the thermoplastic resin material (Rt) passes and which merges with an outer peripheral portion in the main flow channel (F1) is formed in an outer peripheral portion of the main body, and a second sub-flow channel (F3) through which a reinforcing fiber material (4) passes and which merges with the main flow channel (F1) at a position more upstream than a merging position of the main flow channel (F1) and the first sub-flow channel (F2) is formed.

Description

TECHNICAL FIELD

[0001] The present application relates to a molding die for manufacturing a reinforcing bar body which can be applied to reinforced concrete or the like, and a manufacturing method of a reinforcing bar body using the same. BACKGROUND

[0002] As such a reinforcing bar body, instead of an existing iron reinforcing bar body, a reinforcing bar body using basalt fibers which does not rust and can maintain the strength of concrete for a long time is attracting attention. As such a reinforcing bar body, for example, as shown in Patent Literature 1, a reinforcing bar body is proposed which has a structure in which a basalt fiber bundle is used as a core material and a thermoplastic resin layer of a prescribed thickness is coated around the same. Moreover, as a method of forming a resin layer around a core material, conventionally, as shown in the above Patent Literature 1, an impregnation method is mostly used in which the core material is passed through a molten solution of resin.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Laid-Open No. 2012-251378 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, the impregnation method has a problem in that the scale of the entire device becomes large and the manufacturing cost becomes high due to the need to provide an accumulation tank of molten resin or the like.

[0008] Therefore, the present application solves such a problem, and aims to provide a reinforcing bar body molding die which can easily and inexpensively manufacture a reinforcing bar body having sufficient strength, and a manufacturing method of a reinforcing bar body using the same.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] In order to achieve the above object, in the reinforcing bar body molding die (1) of the present first application, a main flow path (Fl) through which a thermoplastic resin material (Rt) output from an extruder (2) passes is formed in a central portion of a die main body, and a first sub-flow path (F2) through which the thermoplastic resin material (Rt) passes and which merges with an outer peripheral portion in the main flow path (Fl) is formed in an outer peripheral portion of the die main body, and a second sub-flow path (F3) through which a reinforcing fiber material (4) passes and which merges with the main flow path (Fl) at a position more upstream than a merging position of the main flow path (Fl) and the first sub-flow path (F2) is formed.

[0011] According to the first invention, a reinforcing bar body in which reinforcing fibers impregnated with a thermoplastic resin material are located in a central portion and the periphery thereof is covered with a thermoplastic resin material of a prescribed thickness can be obtained simply and inexpensively by an extruder and a molding die.

[0012] In the reinforcing bar body molding die (1) of the second invention, a plurality of cylindrical dies (11 to 14) are joined from the upstream side to the downstream side, and the above-described main runner (Fl), the above-described first sub-runner (F2), and the above-described second sub-runner (F3) are formed in these dies (11 to 14).

[0013] According to the second invention, a reinforcing bar body molding die can be easily manufactured by joining a plurality of cylindrical dies.

[0014] In the reinforcing bar body molding die (1) of the third invention, at least the downstream portion of the above-described first sub-runner (F2) is provided as a full-circumferential runner of an annular cross section, and the diameter and thickness of the annular cross section are reduced toward the downstream side.

[0015] According to the third invention, the periphery of reinforcing fibers impregnated with a thermoplastic resin material located in a central portion can be well covered with a thermoplastic resin material of a prescribed thickness.

[0016] In the reinforcing bar body molding die (1) of the fourth invention, the above-described second sub-runner (F3) is formed so as to be curved in the direction along the main runner (Fl).

[0017] According to the fourth invention, a thermoplastic resin material can be well impregnated into reinforcing fibers.

[0018] In the reinforcing bar body molding die (1) of the fifth invention, the above-described second sub-runner (F3) is formed at a plurality of positions in the circumferential direction within the main body.

[0019] According to the fifth invention, by forming the second sub-runner at a plurality of positions in the circumferential direction within the main body, reinforcing fibers can be divided into small portions and supplied to the main runner, and a thermoplastic resin material can be well impregnated between the reinforcing fibers. In this case, since the complexity of the die is taken into account, it is preferable that the second sub-runner be formed at two to four positions in the circumferential direction.

[0020] In the method for manufacturing a reinforcing bar body using a reinforcing bar body molding die according to the sixth invention, the above-described reinforcing fiber material (4) is subjected to air lofting processing and used.

[0021] According to the sixth invention, impregnation of a thermoplastic resin material into reinforcing fibers can be performed more favorably.

[0022] The symbols in parentheses above are shown for reference to correspond with the specific methods described in the embodiments described later.

[0023] Invention Effects

[0024] As described above, the steel bar forming mold and the method for manufacturing steel bars using the steel bar forming mold according to the present invention can easily and inexpensively manufacture steel bars with sufficient strength. Attached Figure Description

[0025] Figure 1 This is a perspective view showing the overall configuration of a steel bar manufacturing apparatus equipped with a steel bar forming mold according to an embodiment of the present invention.

[0026] Figure 2 This is an overall longitudinal section view of the mold used for forming steel bar bars.

[0027] Figure 3 This is a longitudinal sectional view of the mold being supplied.

[0028] Figure 4 It is a front view of the mold being supplied, and it is Figure 3 The X-direction view.

[0029] Figure 5 This is a longitudinal section view of the confluence mold.

[0030] Figure 6 It is a front view of the confluence mold, and it is Figure 5 The Y-direction view.

[0031] Figure 7 This is a longitudinal section view of the covering mold.

[0032] Figure 8 This is a longitudinal section view of the forming mold.

[0033] Figure 9 This is a cross-sectional view of the fluffy nozzle.

[0034] Symbol Explanation

[0035] 1… Die for forming steel bar body, 11… Supply die, 12… Confluence die, 13… Covering die, 14… Forming die, 2… Extruder, 4… Basalt fiber (reinforcing fiber), 7… Fluffy nozzle, F1… Main channel, F2… First secondary channel, F3… Second secondary channel, Rt… PP resin (thermoplastic resin material). Detailed Implementation

[0036] Furthermore, the embodiments described below are merely examples, and various design modifications made by those skilled in the art without departing from the spirit of the invention are also included within the scope of the invention.

[0037] Figure 1 The diagram shows the overall structure of a steel bar forming apparatus equipped with the steel bar forming mold (hereinafter, forming mold) 1 of the present invention. Figure 1 The extruder 2 is equipped with a known structure, and polypropylene (PP) resin Rt, a thermoplastic resin material, is supplied into the extruder 2 from a feed hopper provided on the upper surface of one end. The PP resin Rt is heated to a specified temperature and becomes molten in the extruder 2, and is then supplied to a forming die 1 that is connected to the other end of the extruder 2 via an internal screw. Details of the forming die 1 will be described below.

[0038] The main body of the forming mold 1 is cylindrical. It is constructed by combining four molds: the supply mold 11, the confluence mold 12, the coating mold 13, and the forming mold 14. A cross-sectional view of the mold is shown below. Figure 2 . Figure 3 The figure shows a longitudinal sectional view of the supply mold 11. Figure 4 The middle shows Figure 3 The X-axis view is a front view of the supply die 11. Regarding the supply die 11, one end face 11a, with its central portion raised in an arc shape, covers the outlet opening 21 at the other end of the extruder 2. A through hole 111 is formed in the center of the supply die 11, extending from one end face 11a to the other end face 11b. The through hole 111 passes through the center of a guide portion 112, whose diameter decreases from the center of the other end face 11b of the supply die 11 and protrudes towards the front end.

[0039] A plurality of through holes 113 are formed at intervals around the center portion 115 of the raised end face of the supply mold 11, extending to the other end face 11b. In addition, through holes 114 are formed in the supply mold 11, which are radially symmetrical from the outer circumferential surface and bend and extend toward the center in the longitudinal section. These through holes 114 reach the center of the other end face 11b and open therein to merge with the flow.

[0040] Figure 5 The image shows a longitudinal sectional view of the confluence mold 12. Figure 6 The middle shows Figure 5 The front view from the Y direction. A through hole 121 is formed in the center of the confluence mold 12. The through hole 121 has a large opening in the inner circumference of one end face 12a, and the diameter gradually decreases in a conical shape towards the other end, reaching the inner circumference 122 of the other end face 12b that protrudes in a circle.

[0041] Figure 7The diagram shows a longitudinal sectional view of the covering mold 13. Regarding the covering mold 13, the inner periphery of one end face 13a is recessed to a certain depth and formed as a circular recess 131. A through hole 132 extending to the other end face 13b is formed at the center of the circular recess 131. Position adjustment bolts 133 are provided at equal intervals at multiple locations along the circumference of the peripheral wall of the circular recess 131, extending from the outside.

[0042] Figure 8 The figure shows a longitudinal sectional view of the forming mold 14. A through hole 141 is formed in the center of the forming mold 14. The diameter of the through hole 141 gradually decreases from one end face 14a and is equal to the outer diameter of the steel bar body, which is the final product.

[0043] The supply mold 11, confluence mold 12, coating mold 13, and forming mold 14 are combined and arranged as described below. That is, in the protruding guide portion 112 of the supply mold 11 ( Figure 3 ) enters the through hole 121 of the confluence mold 12 ( Figure 5 In the state of being inside the confluence mold 12, the bolts are inserted into the bolt holes 123 that are equally spaced on the outer periphery of the confluence mold 12. Figure 6 These bolts are installed in bolt holes 116 that are equally spaced on the outer periphery of the supply mold 11. Figure 4 The forming die 11 and the confluence die 12 are thus integrally fixed to the extruder 2. The bolts are screwed into the screw holes (not shown) located around the outlet opening 21 of the extruder 2.

[0044] Regarding the covering mold 13, with the protruding inner circumference 122 of the confluence mold 12 inserted into the circular recess 131, bolts are inserted into the bolt holes 134 that are evenly spaced on its outer circumference. Figure 7 These bolts are screwed into the equally spaced screw holes 124 on the inner circumference 122 of the confluence mold 12. Figure 6 It is then fixed to the confluence mold 12. At this time, the front end of the protruding guide portion 112 of the supply mold 11 enters the through hole 132 of the covering mold 13.

[0045] Regarding the forming mold 14, bolts are inserted into bolt holes 142 that are equally spaced on its outer periphery. Figure 8 ), and screw these bolts into the screw holes 135 that are evenly spaced on the inner circumference of the covering mold 13. Figure 7 And it is fixed to the covering mold 13.

[0046] The forming die 1, which is formed by combining the supply die 11, the confluence die 12, the coating die 13, and the forming die 14 as described above, is fixed to the outlet opening 21 of the extruder 2. Figure 2In this configuration, the main flow channel F1 is formed by the through hole 111 of the supply mold 11 and the through hole 141 of the forming mold 14, which are interconnected. In addition, the through hole 113 of the supply mold 11, the gap 125 generated between the outer periphery of the guide portion 112 of the supply mold 11 and the inner periphery of the through hole 121 of the confluence mold 12, and the gap 136 generated between the outer periphery of the front end of the guide portion 112 of the supply mold 11 and the inner periphery of the through hole 132 of the covering mold 13 are interconnected to form a first secondary flow channel F2 that merges with the outer periphery of the main flow channel F1 at the boundary with the forming mold 14.

[0047] Furthermore, regarding the first secondary flow channel F2, within the merging mold 12, the diameter of its annular cross-section gradually decreases until it reaches the covering mold 13, where it becomes a full-circuit flow channel with an annular cross-section of the desired diameter and thickness. Additionally, the curved and extending through-hole 114 within the supply mold 11 forms a second secondary flow channel F3 that merges with the main flow channel F1 at the center of the other end face 11b of the supply mold 11, upstream of the merging position of the main flow channel F1 and the first secondary flow channel F2.

[0048] In the case of manufacturing steel bar bodies, such as Figure 1 As shown, basalt fiber bundles 4, which serve as reinforcing fiber materials, are drawn from a pair of coils 3 and supplied to a second secondary flow channel F3, which has an opening on the outer periphery of the supply mold 11 constituting the forming mold 1. From the second secondary flow channel F3, they pass through the main flow channel F1, which merges with the main flow channel, and then through the cooling water 51 of the cooling device 5 in the rear section of the forming mold 1. Finally, they are held from above and below by the return belt 6 in the final section. Furthermore, an example of the thickness of the basalt fiber bundles 4 is 4800 TEX.

[0049] In addition, the basalt fiber bundle 4 extracted from coil 3 passes through the coil 3 at different points along the way. Figure 9 The fluffy nozzle 7, as shown, opens the basalt fiber bundles 4 by supplying air 71 to them. The basalt fiber bundles 4, fluffed and opened by the air, are then fed through the tension roller 8 to the opening of the second auxiliary flow channel F3. Here, in Figure 1 For ease of understanding, the opening position of the second sub-channel F3 is different from the actual position.

[0050] In this state, the basalt fiber bundle 4 is drawn straight back without twisting using the retraction belt 6, and molten PP resin Rt is supplied from the extruder 2 to the main flow channel F1 and the first secondary flow channel F2 of the forming die 1. The basalt fiber bundle 4 in its open state is supplied from the second secondary flow channel F3, which merges midway, to the PP resin Rt flowing in the main flow channel F1. The PP resin Rt effectively impregnates the basalt fibers. Further downstream, PP resin Rt is supplied from the first secondary flow channel F2 to cover the outer periphery of the basalt fiber bundle impregnated with PP resin Rt. Then, it is cooled using the downstream cooling device 5, resulting in a sufficiently strong reinforcing bar 9 with the basalt fiber bundle 4 impregnated with PP resin Rt located at its center and surrounded by a specified thickness of PP resin Rt. Figure 1 Here, the diameter of the reinforcing bar 9 is approximately 5 mm in one example, and the diameter of the central part is approximately 4 mm to 4.5 mm in another example. The tensile strength of the reinforcing bar 9 that has been achieved is approximately 15 kN.

[0051] Furthermore, in the above embodiment, the second secondary flow channels are formed at two locations in the radially symmetrical circumferential direction. However, when the reinforcing fibers are divided into small portions and supplied to the main flow channel, the thermoplastic resin material can be better impregnated between the reinforcing fibers. If the complexity of the mold is taken into consideration, it is preferable to form the second secondary flow channels at two to four locations in the circumferential direction.

[0052] In addition to PP resin, polyethylene resin, nylon resin, polyester resin, etc., can be used as the thermoplastic resin material in the above embodiments. Furthermore, in addition to basalt fiber, inorganic fibers such as glass fiber and carbon fiber, and organic fibers such as aramid fiber and acrylic fiber can be used as the reinforcing fiber.

[0053] According to this embodiment, compared with the existing impregnation method, there is no need to set up a molten resin accumulation tank, so the overall device becomes more compact, reducing manufacturing costs and enabling the simple and inexpensive manufacture of steel bars with sufficient strength. Furthermore, the specific structure of the molding die does not necessarily need to be... Figure 2 The structure shown.

Claims

1. A die for forming a steel bar, comprising a main flow channel formed at the center of a main body, which serves as a through hole extending along the extrusion direction of an extruder for passing thermoplastic resin material output from an extruder; a first secondary flow channel formed at the outer periphery of the main body, having a full-circumferential flow channel with at least a downstream annular cross-section, for passing the thermoplastic resin material and merging with the outer periphery of the main flow channel; and a second secondary flow channel formed for passing reinforcing fiber material, configured to connect to the main flow channel at a position upstream of the merging point of the main flow channel and the first secondary flow channel, and for supplying the reinforcing fiber material into the main flow channel. The through hole is hollow along the entire length of the main channel, thus the main channel is configured to output a solid rod shape.

2. The mold for forming steel bar bodies according to claim 1, wherein, Multiple cylindrical molds are joined from the upstream side to the downstream side, and the main flow channel, the first secondary flow channel, and the second secondary flow channel are formed within these molds.

3. The mold for forming steel bars according to claim 1 or 2, wherein, The diameter and thickness of the annular cross-section of the first secondary flow channel are reduced downstream.

4. The mold for forming steel bar bodies according to any one of claims 1 to 3, wherein, The second secondary channel is formed by bending in the direction of the main channel.

5. The mold for forming steel bar bodies according to any one of claims 1 to 4, wherein, The second secondary flow channel is formed at multiple circumferential locations within the main body.

6. A method for manufacturing a reinforcing bar, the method using a mold for forming a reinforcing bar according to any one of claims 1 to 5, used for air-fluffing the reinforcing fiber material.

Images