Tubular body, manufacturing apparatus for tubular body, and manufacturing method for tubular body

Abstract

To provide a tubular body capable of improving appearance and suppressing the decrease of strength, and a method of manufacturing the same.SOLUTION: Provided is a method of manufacturing a tubular body, comprising: a first step of laminating prepregs to form a tubular laminate 20 extending in an axial direction and having a hollow portion i inside; a second step of setting the laminate 20 in a cavity 35 of a mold 30; and a third step of heat molding that comprises applying pressure, in the cavity 35, to the hollow portion i for pressing against a surface 35a of the cavity 35 while expanding the laminate 20. The mold 30 includes a first mold 31 for forming a first boundary of cavity 35. The first mold 31 is of a non-dividing type with no parting lines extending axially on the surface 35a of the cavity 35.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present disclosure relates to a tubular body, a tubular body manufacturing apparatus, and a tubular body manufacturing method. [Background technology]

[0002] 2. Description of the Related Art In recent years, various methods have been proposed for producing tubular bodies such as golf club shafts using FRP (Fiber Reinforced Plastic) by internal pressure molding.

[0003] For example, Patent Document 1 listed below describes a method for manufacturing a fiber-reinforced plastic pipe, in which prepreg is laminated on the outer peripheral surface of an elastic, heat-resistant hollow core mold, which is placed in a molding die, the hollow core mold is expanded with a pressurized fluid to bring the outer peripheral surface of the prepreg into close contact with the cavity of the molding die, the prepreg is hardened and molded in this state under heat and pressure, and after molding, the pressure inside the core mold is reduced and the hollow core mold is pulled out and removed from the molded product. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 51-23575 Summary of the Invention [Problem to be solved by the invention]

[0005] In the internal pressure molding method for manufacturing a tubular body (especially a long tubular body having a length of 500 mm or more in the axial direction), a split mold that is divided into two parts, an upper part and a lower part, is usually used as the molding mold as described above. However, such a split mold has a pair of parting lines (split surfaces) extending in the axial direction in the cavity. Since minute gaps are inevitably present at the parting lines, the molded product formed in the cavity has irregularities such as burrs, that is, parting line marks, due to the material flowing into the gaps. Such parting line marks deteriorate the appearance of the tubular body.

[0006] In addition, during the heat molding of the tubular body, a part of the material flows into the gaps at the parting line, which reduces the pressure applied to the material at that portion, and this may result in the generation of voids, etc. Furthermore, when the parting line marks are removed by grinding or cutting after the tubular body is molded, the reinforcing fibers may be cut in that area. These voids and cut reinforcing fibers may lead to a decrease in the strength of the tubular body.

[0007] The present disclosure has been devised in consideration of the above-mentioned problems, and has as its main object to provide a tubular body and a manufacturing method thereof that can improve the appearance and suppress a decrease in strength. [Means for solving the problem]

[0008] The present disclosure relates to a method for manufacturing a tubular body, comprising: a first step of forming a tubular laminate that extends in an axial direction and has a hollow portion therein by stacking prepregs; a second step of setting the laminate in a cavity of a mold; and a third step of applying pressure to the hollow portion within the cavity to expand the laminate while pressing it against a surface of the cavity to heat mold it, wherein the mold includes a first mold that forms a first axial range of the cavity, and the first mold is a non-split type that does not have a parting line extending in the axial direction on the surface of the cavity. Effect of the Invention

[0009] The manufacturing method of the tubular body of the present disclosure employs the above steps, thereby making it possible to manufacture a tubular body that can improve its appearance and suppress a decrease in strength.

[0010] Furthermore, by adopting the above-described configuration, the tubular body of the present disclosure can improve its appearance and suppress a decrease in strength. [Brief description of the drawings]

[0011] [Figure 1]1 is a flowchart illustrating an example of a manufacturing method according to the present disclosure. [Diagram 2] FIG. 2 is a side view of a mandrel used in the manufacturing method of the present embodiment. [Diagram 3] FIG. 2 is a side view of a mandrel and a laminate for explaining a first step of the embodiment. [Figure 4] FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. [Diagram 5] FIG. 4 is a side view of a mold for explaining a second step in this embodiment. [Figure 6] 6 is a cross-sectional view taken along the line VI-VI in FIG. 5 and FIG. 7. [Figure 7] FIG. 13 is a side view showing a modified example of the mold. [Figure 8] FIG. 4 is a cross-sectional view of a mold for explaining a second step in this embodiment. [Figure 9] FIG. 11 is a cross-sectional view of a mold for illustrating a third step in this embodiment. [Figure 10] FIG. 2 is an overall side view of the tubular body of the present embodiment. [Figure 11] FIG. 11 is a cross-sectional view of a mold showing an example of a fourth step. [Figure 12] FIG. 11 is a side view of a mold according to a second embodiment. [Figure 13] 13 is a cross-sectional view taken along line XIII-XIII in FIG. 12. [Figure 14] 14 is a cross-sectional view taken along line XIV-XIV in FIG. 12. [Figure 15] 13 is a cross-sectional view taken along line XV-XV in FIG. 12. [Figure 16] FIG. 2 is a side view of the golf club of the present embodiment. [Figure 17] FIG. 2 is a development view of the prepregs of the examples and comparative examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, some embodiments of the present disclosure will be described. The representative embodiments disclosed below are not intended to be limiting in any way. Furthermore, the embodiments of the present disclosure can be used alone or in various combinations. In addition, in the following embodiments, the same or common elements are given the same reference numerals, and duplicated descriptions are omitted.

[0013] 1 shows the procedure of one embodiment of the method for manufacturing a tubular body of this embodiment. In this embodiment, the following description is given taking as an example a case where the tubular body is an FRP golf club shaft. However, the tubular body is not limited to a golf club shaft, and can be applied to various tubular bodies such as fishing rods, tennis rackets, and various structural pipes.

[0014] As shown in FIG. 1, the method for producing a tubular body of this embodiment includes a first step S1, a second step S2, a third step S3, and a fourth step S4.

[0015] [1st process S1] In the first step S1 of this embodiment, prepregs are laminated to form a laminate that extends in the axial direction and has a hollow portion therein.

[0016] The prepreg is a composite of fibers and uncured (including semi-cured) matrix resin, and a sheet-like prepreg is used in this embodiment. The prepreg is heated, for example, using a mold or the like, so that the matrix resin hardens into a predetermined shape and forms a tubular body as an FRP molded product.

[0017] The fibers of the prepreg are, for example, carbon fibers, and are oriented substantially in one direction in this embodiment. A prepreg in which the fibers are oriented substantially in one direction in this manner is also called a unidirectional prepreg. In another embodiment, a prepreg sheet in which the fibers are woven can be used as the prepreg. In addition to carbon fibers, examples of the fibers of the prepreg include glass fibers, metal fibers (boron, titanium, tungsten, stainless steel, etc.), and aramid fibers, and one or more of these can be used.

[0018] Examples of the matrix resin of the prepreg include thermosetting resins such as epoxy resins, unsaturated polyester resins, phenol resins, and vinyl ester resins, and one or more of these can be used.

[0019] The type of prepreg, i.e., the elastic modulus of the fiber, the basis weight of the prepreg, the matrix resin and size, the number of layers, etc. are appropriately determined based on the required performance of the golf club shaft (e.g., the length, mass, outer diameter, inner diameter, bending rigidity, torque, etc. of the shaft).

[0020] Fig. 2 shows a side view of mandrel 10, which is a core metal for forming a laminate for a golf club shaft. Fig. 3 shows a side view of laminate 20 in which prepreg 22 is wound around mandrel 10, and Fig. 4 shows a cross-sectional view taken along line IV-IV.

[0021] As shown in Fig. 2, the mandrel 10 is, for example, cylindrical and has a desired taper angle in this embodiment. The axial length, outer diameter, taper angle, etc. of the mandrel can be appropriately set depending on the golf club shaft to be manufactured. As an example, the total length of the mandrel 10 is generally about 800 to 1400 mm, the diameter of the large diameter end 10a is about 10 to 15 mm, and the diameter of the small diameter end 10b is about 3 to 6 mm. In addition, for example, a chuck portion 12 may be provided on the side of the large diameter end 10a of the mandrel 10.

[0022] As shown in Figures 3 and 4, in this embodiment, a laminate 20 of prepregs 22 is obtained by sequentially winding a plurality of prepregs 22 around a mandrel 10. In this embodiment, a case where the laminate 20 is composed of five prepregs 22a to 22d is illustrated. Specifically, the prepregs 22 are composed of first, second, third, fourth, and fifth prepregs 22a to 22e which are sequentially wound from the inside around the mandrel 10. In another aspect, the laminate 20 may be formed by winding one prepreg.

[0023] Next, the laminate 20 is removed from the mandrel 10. This results in a pipe-shaped laminate 20 having a hollow portion i therein. It is preferable to form a thin film of lubricant on the surface of the mandrel 10 prior to winding and laminating the prepreg 22 around the mandrel 10, since this allows the laminate 20 to be easily removed from the mandrel 10.

[0024] In the first step of this embodiment, the laminate 20 is formed using the mandrel 10, but it is not essential to use the mandrel 10. For example, the prepreg 22 may be wound around the outside of an elastomer tube, which will be described later, in a suitably expanded state.

[0025] [Second process] Fig. 5 shows a side view of a mold 30 included in a tubular body manufacturing apparatus used in this embodiment. Fig. 6 is a cross-sectional view taken along line VI-VI in Fig. 5. As shown in Figs. 1, 5 and 6, in the second step S2 of this embodiment, the laminate 20 formed in the first step S1 is set in a cavity 35 of the mold 30.

[0026] The mold 30 of this embodiment includes, for example, a first mold 31. The first mold 31 forms a first range L1 in the axial direction of the cavity 35. In this embodiment, the first range L1 is the entire range in the axial direction of the cavity 35 (hereinafter, this form is referred to as the "first embodiment" of the mold). The mold 30 of this embodiment is composed of only the first mold 31.

[0027] 5 and 6, the first mold 31 is a non-split type that does not have a parting line extending in the axial direction on the surface 35a of the cavity 35. That is, the first mold 31 of this embodiment is not a split type that can be separated into upper and lower parts, but is a non-split type with a continuous cross section as shown in FIG.

[0028] The mold 30 of this embodiment has a first end 30a and a second end 30b in the axial direction and extends therebetween. The axial direction of the mold 30 corresponds to the axial direction of the laminate 20. Although not particularly limited, the axial length of the mold 30 of this embodiment may be, for example, about 800 to 1400 mm. In addition, a heat source (not shown) is connected to the mold 30. This allows the surface 35a of the cavity 35 of the mold 30 to be heated to a temperature required to promote hardening of the prepreg.

[0029] The cavity 35 has, for example, a surface 35a corresponding to the outer surface of the tubular body to be molded. The cavity 35 in this embodiment has, for example, a circular cross section, and its inner diameter is formed to be larger than the outer diameter of the laminate 20. The inner diameter of the cavity 35 may be constant or may be tapered.

[0030] The cavity 35 extends from the first end 30a of the mold 30 in the axial direction inside the mold. The end of the cavity 35 on the second end 30b side is terminated at the tip of the second end 30b. In this embodiment, the first end 30a side of the cavity 35 molds the butt side (grip side) of the golf club shaft, and the second end 30b side of the cavity 35 molds the tip side (golf club head side) of the golf club shaft. In another embodiment, the cavity 35 may be formed to open to both sides of the mold 30 in the axial direction as shown in FIG. 7.

[0031] Returning to FIG. 5, an air hole 36 communicating with the cavity 35 is formed in the second end 30b of the mold 30 of this embodiment. This air hole 36 enables air to be exhausted between the surface 35a of the cavity 35 and the laminate 20, or conversely, enables high-pressure air to be supplied between the surface 35a of the cavity 35 and the laminate 20. If necessary, the air hole 36 may be connected to a vacuum device or a high-pressure air source. Note that the air hole 36 is an optional element in the present disclosure and may be omitted.

[0032] FIG. 8 shows a cross-sectional view of the prepreg laminate 20 set in the cavity 35. In FIG. 8, the difference between the inner diameter of the cavity 35 and the outer diameter of the laminate 20 is exaggerated. In this embodiment, the laminate 20 is inserted into the cavity 35 from the first end 30a side of the mold 30 and set in a predetermined position. Furthermore, in the second step S2 of this embodiment, the elastomer tube 40 in a contracted state is inserted into the hollow portion i of the laminate 20. One end 40a of the elastomer tube 40 is closed, and the other end 40b side is connected to a pressure source (not shown). For example, it is desirable that the elastomer tube 40 is inserted into the laminate 20 in advance, and both are inserted into the cavity 35 at the same time. In another embodiment, the elastomer tube 40 may be inserted into the cavity 35 after the laminate 20.

[0033] [3rd step] Fig. 9 shows a cross-sectional view of the mold 30 for explaining the third step S3 of this embodiment. As shown in Fig. 9, in the third step S3, pressure is applied to the hollow portion i of the laminate 20 in the cavity 35, and the laminate 20 is pressed against the surface 35a of the cavity 35 while expanding, thereby being heated and molded. In this embodiment, a high-pressure fluid F is supplied into the elastomer tube 40. This causes the elastomer tube 40 to expand, and pressure is applied to the laminate 20 through the elastomer tube 40, causing the laminate 20 to expand and deform.

[0034] In the third step, the laminate 20 expands and deforms into a shape defined by the cavity 35 and the elastomer tube 40, while receiving heat from the surface 35a of the cavity 35, and hardening of the matrix resin proceeds. Here, the mold 30 of this embodiment is made of a non-split first mold 31 that does not have a parting line, thereby suppressing escape of the matrix resin material that occurs in gaps at the parting line as in conventional split molds, and also suppressing the generation of voids in the laminate 20 due to a decrease in molding pressure caused by this escape.

[0035] [4th step] In the fourth step S4, when the heat molding using the mold 30 is completed, the elastomer tube 40 is shrunk and the tubular body 1 (i.e., golf club shaft) is removed from the mold 30. This allows the production of the tubular body 1 as shown in FIG. 10. As is clear from FIG. 10, the tubular body 1 produced by the production method of this embodiment does not have parting line marks extending in the axial direction as formed on conventional tubular bodies. Therefore, the appearance of the tubular body 1 is improved. Furthermore, since the tubular body 1 formed with the first mold 31 does not have parting line marks, polishing to remove parting line marks is not required, and thus a decrease in the strength of the tubular body 1 is suppressed.

[0036] Therefore, the tubular body 1 shown in Figure 10, which is formed by curing the prepreg laminate 20, includes a first portion 101 extending in the axial direction, and the outer surface of the first portion 101 is not polished and does not have any parting line marks extending in the axial direction.

[0037] Various methods can be used to remove the tubular body 1 from the mold 30. For example, high-pressure air may be supplied between the tubular body 1 and the surface 35a of the cavity 35 through the air hole 36. This allows the tubular body 1 to be separated from the surface of the cavity 35 and pulled out from the first end 30a side of the mold 30.

[0038] In another embodiment, both may be cooled at the same time. In this case, the laminate 20 shrinks more than the first mold 31, and the tubular body 1 can be easily separated from the surface 35a of the cavity 35. Furthermore, ultrasonic vibration or the like may be applied to the first mold 31 to promote the release of the laminate 20.

[0039] 11, a cylindrical jig 50 having a threaded outer circumferential surface may be attached to the laminate 20 in advance. The jig 50 has an axial length that extends beyond the first end 30a of the mold 30. After the laminate 20 is molded, a pull-out handle 51 or the like may be screwed onto the jig 50, and the laminate 20 may be pulled out of the cavity 35.

[0040] [Second embodiment] Fig. 12 shows a side view of the second embodiment of the mold 30. Figs. 13 to 15 show cross-sectional views taken along lines XIII-XIII, XIV-XIV, and XV-XV in Fig. 12, respectively. The mold 30 of this embodiment differs from the mold 30 of the first embodiment in that it includes a first mold 31 and at least one second mold 32. In this embodiment, the second mold 32 includes a butt-side second mold 32a and a tip-side second mold 32b, with the first mold 31 disposed therebetween.

[0041] The first mold 31 forms a first area L1 in the axial direction of the cavity 35. In this embodiment, the first area L1 is tapered so that the inner diameter becomes smaller toward the second end 30b of the mold 30, and is open on both axial sides of the first mold 31. Similarly to the first embodiment, the first mold 31 is a non-split type that does not have a parting line extending in the axial direction on the surface 35a of the cavity 35.

[0042] The butt-side second die 32a and the tip-side second die 32b respectively form second regions L2a and L2b on both axial sides of the cavity 35. In this manner, the second regions L2a and L2b in this embodiment form both axial ends of the cavity 35. Note that when only one second die 32 is provided, the second region L2 may form only one of the axial ends of the cavity 35.

[0043] The second regions L2a and L2b are axially connected to the first region L1. As a result, the cavity 35 in this embodiment has an axially intermediate portion formed by the first region L1 of the first die 31, and both axial ends formed by the second region L2a of the butt-side second die 32a and the second region L2b of the tip-side second die 32b, respectively.

[0044] 13 and 15, the bat-side second mold 32a and the tip-side second mold 32b are each a split mold having an upper mold 32A and a lower mold 32B that can be separated vertically at parting lines P1 and P2 extending axially on the surface 35a of the cavity 35. In such an embodiment, the area of ​​the tubular body 1 that is molded in the first area L1 of the cavity 35 still does not have parting line marks, and therefore the appearance can be improved and a decrease in strength can be suppressed.

[0045] In a preferred embodiment, the axial length of each of the second regions L2a and L2b is smaller than the axial length of the first region L1. This allows the axial length of the parting line mark that may be formed in the tubular body 1 to be minimized. In such a tubular body 1, it is possible to minimize deterioration of the appearance and reduction in strength compared to conventional tubular bodies in which the parting line mark is formed over the entire length. Note that, when two or more second regions L2a and L2b are included as in this embodiment, it is desirable that the total axial length of these regions is smaller than the axial length of the first region L1.

[0046] Fig. 16 shows a side view of a tubular body 1 which is a golf club shaft manufactured by the mold 30 of the second embodiment. As shown in Fig. 16, the tubular body 1 includes a first portion 101 extending in the axial direction and two second portions. The second portions include a butt-side second portion 102a to which the grip 60 will be attached and a tip-side second portion 102b to which the golf club head 70 will be attached.

[0047] The outer surface of the first portion 101 is not polished and does not have any parting line marks extending in the axial direction, so that a good appearance is provided and a decrease in strength is suppressed.

[0048] In this embodiment, the butt-side second portion 102a is covered at least partially, in this embodiment entirely, with the grip 60 when the grip 60 is attached during the manufacturing process of the golf club G. In other words, the butt-side second portion 102a does not appear on the exterior of the golf club G. Furthermore, the butt-side second portion 102a is reinforced by the grip 60 being attached. Therefore, the golf club shaft of this embodiment is used for the golf club G with the butt-side second portion 102a not polished and with the parting line mark 1A extending in the axial direction. This eliminates the need to polish the parting line mark, improving the productivity of the golf club G.

[0049] On the other hand, the golf club head 70 is attached to the tip side second portion 102b in the manufacturing process of the golf club G. The golf club shaft and the golf club head 70 need to be joined by precisely machining their respective diameters. Since the tip side of the golf club shaft is originally intended to be polished, in this embodiment, the tip side of the cavity 35 is formed by the second range L2b of the split second mold 32b. Therefore, in this embodiment, the tip side second portion 102b is polished and is therefore in a state where it does not have parting line marks extending in the axial direction.

[0050] Moreover, since the mold 30 of the second embodiment is provided with the second mold 32 at one end side in the axial direction, after molding of the tubular body 1, the second mold 32 can be divided to expose a part of the tubular body 1. This has the advantage that the tubular body 1 can be easily released from the mold.

[0051] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the above specific disclosure, and can be implemented with various modifications within the scope of the technical ideas described in the claims. EXAMPLES

[0052] Based on the specifications in Table 1, multiple golf club shafts with an axial length of approximately 1000 mm were prototyped and their appearance and bending strength were evaluated. Note that Fig. 17 shows the configurations of the prepregs s1 to s9 used, and the angle indication on the right side of the figure indicates the angle with respect to the axial direction of the prepreg fibers.

[0053] Next, the prepregs s1 on the upper side in Fig. 17 were wound around a mandrel in order to form a laminate. Note that the laminate had the configuration shown in Table 1 below.

[0054] [Table 1]

[0055] The laminate was then removed from the mandrel, and an elastomer tube was inserted into the hollow portion of the laminate. The laminate together with the elastomer tube was then set in the mold (first mold) of Fig. 5. Then, high-pressure air (0.6 MPa) was supplied to the elastomer tube, and the cavity of the mold was heated and molded at about 80°C for 1 hour and at 130°C for 2 hours (Example).

[0056] On the other hand, in the comparative example, a conventional split mold having upper and lower parts was used, and heat molding was carried out under the same conditions.

[0057] [Shaft appearance evaluation] After the heat molding, the shaft was removed from the mold and its appearance was visually inspected. The presence or absence of parting line marks on the shaft surface was visually inspected by a tester. The presence or absence of parting lines was evaluated in Table 1.

[0058] [Flexural strength (three-point bending test)] For the bending strength, the shaft was supported from below at two points so that the distance between the supports was 300 mm, and a load was applied from above the shaft at the midpoint between the supports, and the load value (peak value) at which the shaft broke was measured. The midpoint at which the load was applied to the shaft was positioned at the center of the tubular body. The measurements were performed under the following conditions. For the comparative example, after the appearance evaluation, the parting line marks were removed with a blade, and then a bending test was performed. The results are expressed as an index with the load value of the comparative example being 100, and the higher the value, the better the result. Test equipment: Shimadzu Corporation, Autograph Loading speed: 20mm / min The test results are shown in Table 2.

[0059] [Table 2]

[0060] As a result of the test, it was confirmed that the shafts of the examples had improved appearance and suppressed a decrease in strength.

[0061] [Note] Regarding the above-described embodiment, the following notes are disclosed.

[0062] The present disclosure (1) provides a method for producing a tubular body, A first step of laminating prepregs to form a tubular laminate extending in an axial direction and having a hollow portion therein; A second step of setting the laminate in a cavity of a mold; and a third step of applying pressure to the hollow portion in the cavity to expand the laminate and press the laminate against a surface of the cavity to heat mold the laminate, The mold includes a first mold forming an axial first area of ​​the cavity, The first mold is a non-split mold that does not have a parting line extending axially on the surface of the cavity. A method for manufacturing a tubular body.

[0063] The present disclosure (2) is the method for producing a tubular body according to the present disclosure (1), in which the first range is the entire range in the axial direction of the cavity.

[0064] The present disclosure (3) further relates to a method for manufacturing a molded product, the mold including at least one second mold forming a second axial range of the cavity, This is the method for producing a tubular body described in the present disclosure (1), wherein the second mold is a split mold having a parting line extending in the axial direction on the surface of the cavity.

[0065] The present disclosure (4) is the method for producing a tubular body according to the present disclosure (3), wherein the axial length of the second range is smaller than the axial length of the first range.

[0066] The present disclosure (5) is the method for producing a tubular body according to the present disclosure (3) or (4), wherein the second region forms one end of the cavity in the axial direction.

[0067] The present disclosure (6) is the method for producing a tubular body according to the present disclosure (3) or (4), wherein the second region forms both axial ends of the cavity.

[0068] The present disclosure (7) is a method for producing a tubular body according to any one of the present disclosures (1) to (6), in which the tubular body is a golf club shaft.

[0069] The present disclosure (8) provides a manufacturing apparatus for manufacturing a tubular body, The mold includes a cavity for hot-molding a tubular laminate having a hollow portion therein and extending in an axial direction by laminating prepregs, The mold includes a first mold forming an axial first area of ​​the cavity, The first mold is a non-split mold having no parting line extending axially on the surface of the cavity. An apparatus for manufacturing a tubular body.

[0070] The present disclosure (9) is the apparatus for manufacturing a tubular body according to the present disclosure (8), wherein the first range is the entire range in the axial direction of the cavity.

[0071] The present disclosure (10) provides a method for manufacturing a molded product, comprising the steps of: forming a second axial region of the cavity; and forming a second axial region of the cavity. The tubular body manufacturing apparatus described in the present disclosure (8), wherein the second mold is a split mold having a parting line extending axially on the surface of the cavity.

[0072] The present disclosure (11) is the apparatus for manufacturing a tubular body according to the present disclosure (10), wherein the axial length of the second range is smaller than the axial length of the first range.

[0073] The present disclosure (12) is the apparatus for manufacturing a tubular body according to the present disclosure (10) or (11), wherein the second region forms one end of the cavity in the axial direction.

[0074] The present disclosure (13) is the apparatus for manufacturing a tubular body according to the present disclosure (10) or (11), wherein the second region forms both axial ends of the cavity.

[0075] The present disclosure (14) provides a tubular body obtained by curing a prepreg laminate, a first portion extending axially; The outer surface of the first portion is not polished and does not have an axially extending parting line mark. It is a tubular body.

[0076] The present disclosure (15) is a tubular body according to the present disclosure (14), wherein the first portion forms the entire axial extent of the tubular body.

[0077] The present disclosure (16) further includes a second portion extending axially on one end side of the first portion, The tubular body according to the present disclosure (14), wherein the outer surface of the second portion is polished and does not have any parting line marks extending in the axial direction.

[0078] The present disclosure (17) further includes a second portion extending axially on one end side of the first portion, The tubular body according to the present disclosure (14), wherein the outer surface of the second portion is not polished and has a parting line mark extending in the axial direction.

[0079] The present disclosure (18) is the tubular body according to the present disclosure (16) or (17), wherein the axial length of the second portion is smaller than the axial length of the first portion.

[0080] The present disclosure (19) is the tubular body according to any one of the present disclosures (16) to (18), wherein the second portion forms one axial end of the tubular body.

[0081] The present disclosure (20) is a golf club shaft using the tubular body according to any one of the present disclosures (14) to (19).

[0082] The present disclosure (21) is a golf club including a golf club shaft using the tubular body described in the present disclosure (16) and a golf club head attached to the second portion.

[0083] The present disclosure (22) is a golf club including a golf club shaft using the tubular body described in the present disclosure (17) and a grip attached to the second portion. [Explanation of symbols]

[0084] 1 Tubular body 20 Laminate 22 Prepreg 30 Mold 31 First Mold 32 Second Mold 32a Second mold for the butt side 32b Chip side second mold 35 Cavity 35a surface 60 Grip 70 Golf Club Head 101 Part 1 102a Second part of the butt 102b Chip side second portion G Golf Club P1, P2 parting lines

Claims

1. A method for manufacturing a tubular body, comprising the steps of: A first step of laminating prepregs to form a tubular laminate extending in an axial direction and having a hollow portion therein; A second step of setting the laminate in a cavity of a mold; and a third step of applying pressure to the hollow portion in the cavity to expand the laminate and press the laminate against a surface of the cavity to heat mold the laminate, The mold includes a first mold forming a first axial range of the cavity and at least one second mold forming a second axial range of the cavity; The first mold is a non-split mold that does not have a parting line extending in an axial direction on the surface of the cavity, the second mold is a split mold having a parting line extending in an axial direction on the surface of the cavity, The first area and the second area are in communication with each other in the axial direction with the same inner diameter. A method for manufacturing a tubular body.

2. A method for manufacturing a tubular body as described in claim 1, wherein the axial length of the second range is smaller than the axial length of the first range.

3. A method for manufacturing a tubular body as described in claim 1 or 2, wherein the second range forms one axial end of the cavity.

4. A method for manufacturing a tubular body as described in claim 1 or 2, wherein the second range forms both axial ends of the cavity.

5. A method for manufacturing a tubular body described in any one of claims 1 to 4, wherein the tubular body is a golf club shaft.

6. A manufacturing apparatus for manufacturing a tubular body, comprising: The mold includes a cavity for hot-molding a tubular laminate having a hollow portion therein and extending in an axial direction by laminating prepregs, The mold includes a first mold forming a first axial range of the cavity and at least one second mold forming a second axial range of the cavity; The first mold is a non-split mold that does not have a parting line extending in the axial direction on a surface of the cavity, the second mold is a split mold having a parting line extending in an axial direction on the surface of the cavity, The first area and the second area are in communication with each other in the axial direction with the same inner diameter. A manufacturing device for tubular bodies.

7. An apparatus for manufacturing a tubular body as described in claim 6, wherein the axial length of the second range is smaller than the axial length of the first range.

8. An apparatus for manufacturing a tubular body as described in claim 6 or 7, wherein the second range forms one axial end of the cavity.

9. An apparatus for manufacturing a tubular body as described in claim 6 or 7, wherein the second range forms both axial ends of the cavity.

10. A tubular body obtained by curing a laminate of prepregs, a first portion extending in an axial direction and a second portion extending in the axial direction on one end side of the first portion, the outer surface of the first portion is not polished and does not include an axially extending parting line; The outer surface of the second portion is not polished and has a parting line mark extending in the axial direction; The first portion and the second portion have the same outer shape and are continuous in the axial direction. Tubular body.

11. A tubular body as described in claim 10, wherein the axial length of the second portion is smaller than the axial length of the first portion.

12. A tubular body as described in claim 10 or 11, wherein the second portion forms one axial end of the tubular body.

13. A golf club shaft using a tubular body described in any one of claims 10 to 12.

14. A golf club comprising a golf club shaft using the tubular body described in claim 10 and a grip attached to the second portion.

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