TUBE BODY INTERMEDIATE PIECE AND METHOD FOR MAKING A TUBE BODY

Abstract

Pipe body intermediate piece with a plurality of fiber layers (13a, 14a) arranged such that they are stacked in a radial direction of a mandrel (1), wherein the plurality of fiber layers (13a, 14a) each has the following: a fibrous body which is arranged with respect to an outer circumferential surface of the mandrel (1) such that it extends in an axial direction of the mandrel (1); and a first fixing element (13b, 14b) which is wound with respect to the outer circumferential surface of the mandrel (1) such that the first fixing element (13b, 14b) is wound with one or more turns in a circumferential direction along the axial direction of the mandrel (1) over the fiber body, wherein the first fixing element (13b) of a lower one from the plurality of fiber layers (13a) and the fiber body of an upper one from the plurality of fiber layers (14a) located on the lower one are stacked at least in the radial direction, and wherein the first fixing elements (13b, 14b) of the plurality of fiber layers (13a, 14a) are arranged in different phases in the axial direction of the mandrel (1) so that they do not overlap each other in the radial direction of the mandrel (1).

Description

[0001] The present invention relates to an intermediate piece of a tubular body, which is used, for example, as a drive shaft of a vehicle, and to a method for manufacturing a tubular body.

[0002] JP H03-265738A discloses that drive shafts (cardan shafts) mounted on vehicles each have a tubular body extending in the forward-reverse direction of the vehicle. The tubular body transmits power generated by a drive system and slowed by a gearbox to a final reduction gearbox. A tubular body made of fiber-reinforced plastic and manufactured using a mandrel is known as a tubular body used for such a drive shaft.

[0003] The JP H08-205650A shows a tubular body with an inner layer, an intermediate layer, and an outer layer. The inner layer is a fiber-reinforced resin layer with reinforcing fibers arranged helically in the axial direction. The intermediate layer contains a fiber-reinforced resin layer with reinforcing fibers arranged axially in the axial direction. The outer layer comprises a fiber-reinforced resin layer with reinforcing fibers. This tubular laminate is created using a lamination process. During the lamination process, the layers are impregnated with resin and then passed through a cylindrical die to be pultruded and shaped.

[0004] JP H08-187797A describes a process for manufacturing tubular fiber-reinforced plastics in which a multitude of yarn spools are rotatably mounted on the sides of a rotating gear. A bore for a mandrel and a twist wheel with a yarn guide arranged around the bore are provided in the center. In this process, resin-impregnated yarn strips are wound around a mandrel in a subsequent process before shaping, so that the reinforcing base material is formed and the mandrel is removed from the reinforcing base material. A heat-shrinkable tape is wound onto the yarn between the subsequent yarn winding process and the shaping step.

[0005] JP 2015-145 104 A describes a method for ensuring the strength and stiffness of a bent part. For this purpose, a prepreg, which is a fiber-reinforced resin material, is applied to the outer surface of the bent section of the part. A shrink band is wrapped around the prepreg parallel to the axis of the core of the bent part to prevent it from moving outwards in the radial direction of the core. After heat curing of the resulting intermediate form, the shrink band is removed to expose the axial composite element with its bent section.

[0006] Known methods for winding a material around a mandrel include the thread winding method, which involves winding a continuous fiber impregnated with a resin, and the film winding method, which involves winding a prepreg (a film produced by impregnating a fiber material with a resin). The thread winding method is advantageous for cost-effective manufacturing but has a problem aligning the fiber material along the axis of the mandrel, or in other words, aligning the fiber material along the axis of the tube body. On the other hand, the film winding method allows for alignment of the fiber material along the axis of the mandrel but has disadvantages in terms of manufacturing costs.

[0007] Assuming that L in this case represents the axial direction length over which fibers are arranged over a mandrel, then r represents the radius of the outer circumferential surface of the mandrel, and θ represents the orientation angle of the fibers with respect to the mandrel (see Fig. 1) If the orientation angle θ is so small that tan θ < |2πr / L|, then the fiber cannot be wound around the mandrel with one or more turns, in which case gravity may cause the fibers to separate from the mandrel.

[0008] The present invention is intended to solve such a problem, and an object of the present invention is to provide a tube body intermediate and a tube body manufacturing method which makes it possible to reduce the displacement of a fiber body while simultaneously reducing the manufacturing costs, even when the orientation angle of the fiber body is small.

[0009] To solve the problems described above, a pipe body intermediate has a plurality of fiber layers stacked in a radial direction of a mandrel, wherein according to the present invention the plurality of fiber layers each has the following: a fiber body arranged with respect to an outer circumferential surface of the mandrel such that it extends in an axial direction of the mandrel;and a first fixing element which is wound with respect to the outer circumferential surface of the mandrel such that the first fixing element is wound with one or more turns in a circumferential direction along the axial direction of the mandrel over the fiber body, wherein the first fixing element of a lower one from the plurality of fiber layers and the fiber body of an upper one from the plurality of fiber layers located on the lower one are stacked at least in the radial direction, and wherein the first fixing elements of the plurality of fiber layers are arranged in different phases in the axial direction of the mandrel, so that they do not overlap each other in the radial direction of the mandrel.

[0010] Furthermore, a tube body manufacturing method of the present invention comprises the following: a step of repeatedly performing a fiber layer formation step to form a plurality of fiber layers, such that the plurality of fiber layers are arranged in such a way that they are stacked in the radial direction of a mandrel, wherein each of the fiber layer formation steps, in order to form a respective fiber layer consisting of a corresponding fiber body and a corresponding first fixing element, comprises the following: an arrangement step for arranging the corresponding fiber body with respect to the outer circumferential surface of a mandrel such that the corresponding fiber body runs in an axial direction of the mandrel;and a fastening step for winding the corresponding first fixing element with respect to the outer circumferential surface of the mandrel such that the corresponding first fixing element is wound with one or more turns in a circumferential direction along the axial direction of the mandrel over the corresponding fiber body;and a forming step, after the step of repeatedly repeating the fiber layer formation step, for impregnating the fiber bodies from the plurality of fiber layers with a resin on the outer circumferential surface of the mandrel and then heating the resin to form the resin, wherein the first fixing element of a lower from the plurality of fiber layers and the fiber body of an upper from the plurality of fiber layers, which is located on the lower one, are stacked at least in the radial direction, and wherein each of the repeated fixing steps comprises arranging the first fixing element of the corresponding fiber layer in a different phase with respect to the first fixing elements arranged in the other fixing steps, in the axial direction of the mandrel, so that they do not overlap with the first fixing elements arranged in the other fixing steps.

[0011] The present invention makes it possible to reduce the displacement of the fibers, even when the alignment angle of the fibers is small, while simultaneously reducing manufacturing costs. Fig. Figure 1 shows a diagram illustrating a pipe body intermediate piece according to an intermediate step of a method which further leads to an object according to an embodiment of the present invention. Fig. Figure 2 shows a diagram illustrating a mandrel and a first carbon fiber layer of the tube body intermediate piece according to an intermediate step of the process before the intermediate step according to Fig. 1. Illustrated schematically. Fig. Figure 3 shows a diagram illustrating a second carbon fiber layer of the tube body intermediate according to an intermediate step of the process after the intermediate step according to Fig. 2 and before the intermediate step according to Fig. 1. Illustrated schematically. Fig. Figure 4 shows a diagram illustrating a third carbon fiber layer of the tube body intermediate according to an intermediate step of the process after the intermediate step according to Fig. 3 and before the intermediate step according to Fig. 1. Illustrated schematically. Fig. Figure 5 shows a diagram schematically illustrating a forming device for producing the tube body according to an exemplary embodiment which is not within the scope of the present invention. Fig. Figure 6 shows a diagram that schematically illustrates a pipe body produced using the pipe body intermediate piece according to the exemplary embodiment. Fig. Figure 7 shows a flowchart illustrating a pipe body manufacturing process according to the exemplary embodiment. Fig. Figure 8 shows a diagram that schematically illustrates an example of the pipe body according to the exemplary embodiment. Fig. Figure 9 shows a cross-sectional view that schematically illustrates a pipe body intermediate piece according to a first embodiment of the present invention. Fig. Figure 10 shows a flowchart illustrating a pipe body manufacturing process according to the first embodiment of the present invention. Fig. Figures 11A to 11D show explanatory diagrams that schematically illustrate the manufacturing process of the pipe body intermediate piece according to the first embodiment of the present invention. Fig. Figure 12 shows a diagram that schematically illustrates a pipe body produced using the pipe body intermediate piece according to the first embodiment of the present invention. Fig. Figure 13 shows a diagram that schematically illustrates a pipe body intermediate piece according to a second embodiment of the present invention. Fig. Figure 14 shows a flowchart illustrating a pipe body manufacturing process according to the second embodiment of the present invention.

[0012] One embodiment of the present invention is described in detail with reference to the drawings, assuming an exemplary case for the manufacture of a vehicle drive shaft (cardan shaft) as a tubular body using a carbon fiber reinforced plastic. In the following descriptions, identical elements are designated with the same reference numerals, and overlapping descriptions are omitted. The drawings referenced in the description are shown in a modified form for easier understanding, so that the dimensions of the parts (e.g., in Fig. 5 and Fig. The form shown in Figure 8, or similar, of the connecting pieces 22 and 23, is not accurately depicted.

[0013] The in Fig. The pipe body intermediate piece 10A shown in Figure 1 is formed by arranging carbon fiber layers on the outer circumferential surface of a mandrel 1 (see Figure 1). Fig. 2) As in Fig. As illustrated in Figure 2, the mandrel 1 is a metal part with a circular cylindrical tube shape. <Pipe body intermediate piece>

[0014] As in Fig. As illustrated in Figure 1, the tube body intermediate piece 10A is a circular cylindrical tube element having a multitude of stacked carbon fiber layers and which is located in the middle of the tube body 20A fabrication process described below (see Figure 1). Fig. 6) is formed. The pipe body intermediate piece 10A has, in sequence from the radial inner side (from the side of the mandrel 1), a first carbon fiber layer 11 (see Fig. 2), a second carbon fiber layer 12 (see Fig. 3) and a third carbon fiber layer 13 (see Fig. 4). The first carbon fiber layer 11, the second carbon fiber layer 12, and the third carbon fiber layer 13 form a reinforced fiber layer which is to be enclosed in the resin 21 of the tube body 20 described below in order to reinforce the resin 21. The tube body intermediate piece 10A further comprises a first fixing element 13b as an element for fixing carbon fibers 13a in the third carbon fiber layer 13. It should be noted that the Fig. 2, Fig. 3 to Fig. 4 only partially illustrate the carbon fiber layers 11, 12 and 13. <<Erste Kohlefaserschicht> >

[0015] As in Fig. As illustrated in Figure 2, the first carbon fiber layer 11 is formed by a plurality of carbon fibers 11a arranged with respect to the outer circumferential surface of the mandrel 1 such that they cover the mandrel 1. The carbon fibers 11a of the first carbon fiber layer 11 are arranged such that they are wound with one or more turns at an angle of 45° to the axis of the mandrel 1 and that they run helically with respect to the axis of the mandrel 1. In other words, the orientation angle θ of the carbon fibers 11a is 45° with respect to the axis X of the mandrel 1. <<Zweite Kohlefaserschicht> >

[0016] As in Fig. As illustrated in Figure 3, the second carbon fiber layer 12 is arranged on the radially outer side of the first carbon fiber layer 11 and is formed by a plurality of carbon fibers 12a arranged to cover the first carbon fiber layer 11. The carbon fibers 12a of the second carbon fiber layer 12 are arranged such that they are wound with one or more turns at an angle of -45° to the axis of the mandrel 1 and are spirally wound to the axis of the mandrel 1. In other words, the orientation angle θ of the carbon fibers 12a is -45° to the axis X of the mandrel 1. <<Dritte Kohlefaserschicht> >

[0017] As in Fig. As illustrated in Figure 4, the third carbon fiber layer 13 is arranged on the radially outer side of the second carbon fiber layer 12 and is formed by: a plurality of carbon fibers 13a arranged to cover the second carbon fiber layer 12; and the first fixing element 13b. The carbon fibers 13a of the third carbon fiber layer 13 are arranged so that they run parallel to the axial direction of the mandrel 1. In other words, the orientation angle θ of the carbon fibers 13a with respect to the axis X of the mandrel 1 is 0°. The length of the carbon fibers 13a is equal to the axial length L of a section of the mandrel 1 on which the carbon fiber layers 11 to 13 are arranged. It should be noted that the mandrel 1 has opposite end sections, which are to be held by devices and on which the carbon fiber layers 11 to 14 are therefore not arranged. <<Erstes Fixierelement> >

[0018] As in Fig. As illustrated in Figure 1, the first fixing element 13b is designed to fix the carbon fibers 13a to the outer circumferential surface of the mandrel 1. The first fixing element 13b is a flexible resin element, for example, with a thread-like or ribbon-like shape. The first fixing element 13b can be made of the same material as the resin 21 described below. The first fixing element 13b can be made of a material that melts due to the heat of a mold 2 and / or the resin 21 in order to be mixed into the resin 21. The first fixing element 13b is arranged such that it is wound with one or more turns so that it is inclined with respect to the axis of the mandrel 1 and that the first fixing element 13b runs helically with respect to the axis of the mandrel 1.

[0019] The first fixing element 13b, as described above, prevents the carbon fibers 13a, which are arranged on the outer circumferential surface of the mandrel 1, which is positioned such that its axial direction is horizontal (i.e., those arranged on the outer circumferential surface of the horizontally positioned mandrel 1), from hanging downwards due to gravity. In particular, the first fixing element 13b appropriately prevents an intermediate section of a portion of carbon fibers 13a located on a lower section of the outer circumferential surface of the mandrel 1 from hanging downwards axially due to gravity. <Herstellungsverfahren des Rohrkörpers>

[0020] The following describes a method for manufacturing a pipe body 20A (see Fig. 6) according to an exemplary embodiment via the pipe body intermediate piece 10A according to the embodiment described above, using the in Fig. 7 flowcharts are described.

[0021] First, a connecting piece (fork stub or shaft stub) 22 (see Fig. 5) arranged at an end section in the axial direction of the mandrel 1 (step S1: installation step of the connecting piece). Subsequently, as in Fig. Figure 2 illustrates how the first carbon fiber layer 11 is formed on the outer circumferential surface of the mandrel 1 by a device not shown (step S2: formation step of the first carbon fiber layer). The following section describes how... Fig. Figure 3 illustrates how the second carbon fiber layer 12 is formed on the outer circumferential surface of the first carbon fiber layer 11 by a device not shown (step S3: formation step of the second carbon fiber layer). Subsequently, as in Fig. 4 shown, carbon fibers 13a of the third carbon fiber layer 13 on the outer circumferential surface of the second carbon fiber layer 12 are formed by a device not shown (step S4: formation step of the third carbon fiber layer / arrangement step).

[0022] The following describes how in Fig. Figure 1 illustrates that the first fixing element 13b is arranged on the outer circumferential surface of the carbon fibers 13a of the third carbon fiber layer 13 by means of a device not shown, whereby the carbon fibers 13a are fixed with respect to the mandrel 1 (step S5: formation step of the third carbon fiber layer, fixing step).

[0023] The steps described above, from the formation step of the first carbon fiber to the fixing step, can be described as a manufacturing process for a tube body intermediate piece, designed to produce the tube body intermediate piece 1oA.

[0024] Then, as in Fig. Figure 5 illustrates how the first carbon fiber layer 11, the second carbon fiber layer 12, and the third carbon fiber layer 13 are impregnated with a resin 21 by means of a molding device (mold) 2. Heat is then applied to the molding device 2 to form the tube body 20A (step S6: molding step). The resin 21 is, for example, a heat-curing resin. In the present embodiment, the mold of the molding device 2 is divided into several parts. During the molding step, while heat is applied to the tube body intermediate 10A, a mold-closing operation is performed after a mold-closing operation that closes the mold of the molding device 2. This operation applies pressure to the closed mold to increase the pressure within the mold, thereby facilitating the curing of the resin 21.It should be noted that, since the description of the present embodiment uses a mold with a plurality of parts, the mold closing and clamping processes are described as having been carried out. However, the clamping process is not strictly necessary. Furthermore, such a mold closing and clamping process is not strictly necessary if the mold is not divided into a plurality of parts. In the [reference to be added]... Fig. In the example shown in Figure 5, the connecting piece (fork stub or shaft stub) 22 is arranged in the axial direction of the mandrel 1 at one end section, and the pipe body intermediate piece 10A extends to an outer circumferential surface of the connecting piece 22. Furthermore, in the molding device 2, an intermediate space (resin reservoir 2b) is formed on the outlet side of a sprue 2a, through which the resin 21 is to be injected in a molten state. The resin 21 injected into the molding device 2 moves via the resin reservoir 2b in the axial direction of the mandrel 1. The resin 21, as described above, penetrates the first carbon fiber layer 11, the second carbon fiber layer 12, and the third carbon fiber layer 13. In a state where the resin 21 has penetrated the carbon fiber layers 11 to 13, heat is applied to the molding device 2 and pressure is applied inside the molding device 2, thereby forming the tube body 20A.During the forming step, the first fixing element 13b can melt due to the heat(s) of the forming device (mold) 2 and / or the resin 21 and can mix with the resin 21.

[0025] The formed tube body 20A and the mandrel 1 are then removed from the forming device 2, and the mandrel 1 is subsequently pulled out of the tube body 20A (step S7: core removal step). A connecting piece (the other fork stub or shaft stub) 23 is then attached to the other end section in the axial direction of the mandrel 1 (step S8: connecting piece attachment step).

[0026] The pipe body intermediate piece 10A according to the embodiment described above has the following: a fiber body (carbon fibers 13a) which is arranged with respect to the outer circumferential surface of the mandrel 1 such that it extends in the axial direction of the mandrel 1; and the first fixing element 13b which is wound with respect to the outer circumferential surface of the mandrel 1 such that the first fixing element 13b is wound over the fiber body with one or more turns in the circumferential direction along the axial direction of the mandrel 1.

[0027] The manufacturing process of the tube body according to the exemplary embodiment comprises the following: an arrangement step for arranging the fiber body (carbon fibers 13a) with respect to the outer circumferential surface of the mandrel 1 such that the fiber body extends in the axial direction of the mandrel 1; a fixing step for winding the first fixing element 13b, which is designed to fix the fiber body with respect to the outer circumferential surface of the mandrel 1, with respect to the outer circumferential surface of the mandrel 1 such that the first fixing element 13b is wound over the fiber body with one or more turns in the circumferential direction along the axial direction of the mandrel 1; and a forming step for impregnating the fiber body with a resin 21 on the outer circumferential surface of the mandrel 1 and then heating the resin 21 to shape the resin 21.

[0028] These designs make it possible to reduce fiber displacement while simultaneously reducing manufacturing costs, even when the orientation angle θ of the fiber body is small. <Erste Ausführungsform>

[0029] A pipe body intermediate piece and a manufacturing method for the pipe body according to a first embodiment of the present invention are described below, with a focus on the differences to the embodiment described above.

[0030] As in Fig. As illustrated in Figure 9, a tube body intermediate piece 10B according to the first embodiment further comprises a fourth carbon fiber layer 14, which is arranged on the radially outer side of the third carbon fiber layer 13. <<Vierte Kohlefaserschicht> >

[0031] The fourth carbon fiber layer 14 is arranged on the radially outer side of the third carbon fiber layer 13 and is formed by: a plurality of carbon fibers 14a arranged to cover the third carbon fiber layer 13; and a first fixing element 14b. The carbon fibers 14a of the fourth carbon fiber layer 14 are arranged such that they run parallel to the axial direction of the mandrel 1. In other words, the orientation angle θ of the carbon fibers 14a with respect to the axis X of the mandrel 1 is 0°. The carbon fibers 14a have a length equal to the axial length L of a section of the mandrel 1 on which the carbon fiber layers 11 to 14 are arranged. <<Erstes Fixierelement> >

[0032] The first fixing element 14b is designed to fix the carbon fibers 14a to the outer circumferential surface of the mandrel 1. The first fixing element 14b is a flexible resin element with, for example, a thread-like or ribbon-like shape. The first fixing element 14b can be made of the same material as the resin 21 described below. The first fixing element 14b can be made of a material that melts due to the heat of a mold 2 and / or the resin 21 in order to mix with the resin 21. The first fixing element 14b is arranged such that it is wound with one or more turns, inclined with respect to the axis of the mandrel 1, and that the first fixing element 14b runs helically with respect to the axis of the mandrel 1.The first fixing element 14b is arranged in a different phase with respect to the first fixing element 13b in the axial direction of the mandrel 1 and parallel to it. In other words, the first fixing element 14b and the first fixing element 13b are arranged such that they do not overlap each other in the radial direction of the mandrel 1.

[0033] The first fixing element 14b described above prevents the carbon fibers 14a, which are arranged on the outer circumferential surface of the mandrel 1, which is positioned such that its axial direction is horizontal (i.e., which are arranged on the outer circumferential surface of the horizontally positioned mandrel 1), from hanging downwards due to gravity. In particular, the first fixing element 14b appropriately prevents an intermediate section of a portion of carbon fibers 14a located in a lower section of the outer circumferential surface of the mandrel 1 from hanging downwards axially due to gravity. < Manufacturing process of the pipe body >

[0034] The following describes a method for manufacturing a pipe body 20B (see Fig. 12) via the pipe body intermediate piece 10B according to the first embodiment using the in Fig. The flowchart shown in the 10 diagrams is described.

[0035] In this manufacturing process, as in Fig. Figure 11A illustrates the carbon fibers 13a of the third carbon fiber layer 13 on the outer circumferential surface of the second carbon fiber layer 12 (see Fig. 7) formed by a device not shown (step S4: Third carbon fiber layer formation step / arrangement step).

[0036] Then, as in Fig. Figure 11B illustrates the first fixing element 13b being arranged on the outer circumferential surface of the carbon fibers 13a of the third carbon fiber layer 13 by a device not shown, thereby fixing the carbon fibers 13a with respect to the mandrel 1 (step S5: Third carbon fiber layer formation step; fixing step).

[0037] Then, as in Fig. Figure 11C illustrates the formation of carbon fibers 14a of the fourth carbon fiber layer 14 on the outer circumferential surface of the third carbon fiber layer 13 by a device not shown (step S4B: Fourth carbon fiber layer formation step / arrangement step).

[0038] Then, as in Fig. Figure 11D illustrates the first fixing element 14b being arranged on the outer circumferential surface of the carbon fibers 14a of the fourth carbon fiber layer 14 by a device not shown, thereby fixing the carbon fibers 14a with respect to the mandrel 1 (step S5B: Fourth carbon fiber layer formation step, fixing step).

[0039] It should be noted that in the Fig. In the illustrated example 9, the carbon fibers 13a of the carbon fiber layer 13 and the carbon fibers 14a of the carbon fiber layer 14 are each arranged closely together in the circumferential direction, and the carbon fibers 14a located on the outside are arranged overlapping on the radially outer side of the carbon fiber layer 13a and the first fixing element 13b located on the inside. In contrast, in the example shown in Fig. Figures 11A to 11D illustrate the carbon fibers 13a of the third carbon fiber layer 13 arranged at intervals in the circumferential direction, and the carbon fibers 14a of the fourth carbon fiber layer 14 are each arranged in the spaces between the carbon fibers 13. In this structure as well, the carbon fibers 14a of the fourth carbon fiber layer 14 are arranged overlapping on the radially outer side of the first fixing element 13b of the third carbon fiber layer 13. In this case, compared to a case in which the carbon fibers 13a and the carbon fibers 14a are fixed only with the first fixing element 14b (a case in which the first fixing element 13b is omitted), the number of carbon fibers 13a to be fixed by the first fixing element 13b and the number of carbon fibers 14a to be fixed by the first fixing element 14b can be reduced, which leads to an increase in the degree of freedom in the design of the first fixing elements 13b, 14b.

[0040] The tube body intermediate piece 10B according to the first embodiment of the present invention comprises a plurality of fiber layers, each containing the fiber body and the first fixing element. The plurality of fiber layers (carbon fibers 13a and carbon fibers 14a) are arranged such that they are stacked in the radial direction of the mandrel 1. The first fixing element 13b of the fiber layer 13, arranged as the lower layer, and the fiber body (carbon fibers 14a) of the fiber layer 14, arranged as the upper layer above the lower layer, are stacked at least in the radial direction. The first fixing element 13b and the first fixing element 14b, each contained in the plurality of fiber layers, are arranged at different phases in the axial direction of the mandrel (and parallel to each other (with the same orientation angle)).In other words, the first fixing element 14b and the first fixing element 13b are arranged such that they do not overlap each other in the radial direction of the mandrel 1.

[0041] The manufacturing process of the tube body according to the first embodiment of the present invention further comprises repeatedly performing the arrangement step and the fixing step prior to the forming step, thereby forming a plurality of fiber layers, each containing the fiber body and the first fixing element such that these are stacked in the radial direction of the mandrel 1. The first fixing element 13b of a lower layer of the plurality of fiber layers and the fiber body (carbon fibers 14a) of an upper layer of the plurality of fiber layers, which is located above the lower layer, are stacked at least in the radial direction. During the repeated fixing step, the first fixing elements 13b, 14b contained in each of the plurality of fiber layers are arranged in different phases in the axial direction of the mandrel 1.

[0042] These designs make it possible to reduce displacement of the fiber body, even if the orientation angle θ of the fiber body is small. Furthermore, compared to a case where the first fixing elements 13b and 14b are arranged in the same phase such that they overlap radially, these designs allow for a reduction in the thickness of the tube body intermediate piece 10B and prevent local stress concentration. <Zweite Ausführungsform>

[0043] A pipe body intermediate piece and a manufacturing method for a pipe section according to a second embodiment of the present invention are described below, with a focus on differences from the first embodiment.

[0044] As in Fig. As illustrated in Figure 13, a tube body intermediate piece 10C according to the second embodiment of the present invention has a pair of second fixing elements 15, 15 as elements for fixing the third carbon fiber layer 13. <<Zweites Fixierelement> >

[0045] The second fixing elements 15 are elements for fixing end sections of the third carbon fiber layer 13 to the outer circumferential surfaces of the end sections in the axial direction of the mandrel 1. The second fixing elements 15 each represent a band-like, flexible resin element with an adhesive portion on one surface side (on the radially inner surface side). The second fixing elements 15 are each wound in a ring shape. The second fixing elements 15 can each consist of the same material as the resin 21 or can each consist of a material that melts due to the heat of a mold 2 and / or the resin 21 in order to mix with the resin 21, like the first fixing element 14b. < Manufacturing process of the pipe body >

[0046] The following describes a method for manufacturing a pipe body via the pipe body intermediate piece 10C according to the second embodiment using the Fig.14 flowcharts are described.

[0047] Between the formation step of the fourth carbon fiber layer (step S4B) and the forming step (step S6), the second fixing elements 15, 15 are arranged on the outer circumferential surface of the opposite end sections of the fourth carbon fiber layer 14 by a device (not shown), so that the opposite end sections of the third carbon fiber layer 13 and the opposite end sections of the fourth carbon fiber layer 14 are fixed with respect to the mandrel 1 (step S5C, fixing step of the opposite end sections). The fixing by the second fixing elements 15, 15 preferably takes place before the fixing (step S5B) by the first fixing elements 14b, 14b. Furthermore, the fixing by the second fixing elements 15, 15 can take place between the formation step of the third carbon fiber layer (step S4) and the formation step of the fourth carbon fiber layer (step S4B).

[0048] The pipe body intermediate piece 10C according to the second embodiment of the present invention has the second fixing elements 15, which fix the opposite end sections of the fiber body with respect to the outer circumferential surface of the mandrel 1.

[0049] According to the manufacturing process of the tube body according to the second embodiment of the present invention, in the fixing step the opposite end sections of the fiber body with respect to the outer circumferential surface of the mandrel 1 are fixed by the second fixing elements 15.

[0050] These designs make it possible to appropriately reduce the displacement of the fiber body, even if the orientation angle θ of the fiber body is small, while simultaneously reducing manufacturing costs.

[0051] Although certain embodiments of the present invention have been described above, it is understood that the present invention is not limited to the embodiments described above and that the embodiments of the present invention can be modified accordingly insofar as they do not deviate from the core of the invention. For example, the first carbon fiber layer 11 and the second carbon fiber layer 12 can be omitted, and the third carbon fiber layer 13 can be applied directly to the outer surface of the mandrel 1.Furthermore, the orientation angle of the carbon fibers 13a of the third carbon fiber layer 13 and the orientation angle of the carbon fibers 14a of the fourth carbon fiber layer 14 are not limited to 0° (not limited to running parallel to the axis of the mandrel 1), but can also represent an angle such that the carbon fibers 13a and the carbon fibers 14a are wound with less than one turn relative to the mandrel 1. In other words, the present invention is preferably used when the orientation angle θ of the carbon fibers 13a satisfies tan θ < |2πr / L|. Moreover, the fiber bodies used in the tube body intermediates 10A to 10C are not limited to the carbon fibers 11a to 14a and can consist of other materials suitable for reinforcing the tube body 20.Furthermore, in the exemplary embodiment, a plurality of the first fixing elements 13b can be arranged in different phases in the axial direction of the mandrel 1 and parallel to each other. Furthermore, in the first embodiment, a plurality of the first fixing elements 13b and a plurality of the first fixing elements 14b can be arranged in different phases in the axial direction of the mandrel 1 and parallel to each other. List of reference symbols: 1 thorn 2 Forming device 2a Sprue 10A, 10B, 10C Pipe body intermediate piece 11 first carbon fiber layer 11a Carbon fibers (first carbon fiber layer) 12 second carbon fiber layer 12a Carbon fibers (second carbon fiber layer) 13 third carbon fiber layer 14 fourth carbon fiber layer 13a, 14a Carbon fiber (fiber body) 13b, 14b first fixing element 15 second fixing element 20A, 20B Pipe body 21 Harz 22 Connecting piece (fork stub or shaft stub) 23 Connector (the other fork stub or shaft stub)

Claims

Tube body intermediate piece with a plurality of fiber layers (13a, 14a) arranged such that they are stacked in a radial direction of a mandrel (1), wherein the plurality of fiber layers (13a, 14a) each has the following: a fiber body arranged with respect to an outer circumferential surface of the mandrel (1) such that it extends in an axial direction of the mandrel (1);and a first fixing element (13b, 14b) which is wound with respect to the outer circumferential surface of the mandrel (1) such that the first fixing element (13b, 14b) is wound with one or more turns in a circumferential direction along the axial direction of the mandrel (1) over the fiber body, wherein the first fixing element (13b) of a lower from the plurality of fiber layers (13a) and the fiber body of an upper from the plurality of fiber layers (14a) located on the lower one are stacked at least in the radial direction, and wherein the first fixing elements (13b, 14b) of the plurality of fiber layers (13a, 14a) are arranged in different phases in the axial direction of the mandrel (1) so that they do not overlap each other in the radial direction of the mandrel (1). Pipe body intermediate piece according to claim 1, further comprising a second fixing element (15) which fixes opposite end sections of the fiber bodies of the plurality of fiber layers (13a, 14a) with respect to the outer circumferential surface of the mandrel (1). Tube body manufacturing method, comprising: a step of repeatedly performing a fiber layer formation step (S2, S3, S4) to form a plurality of fiber layers (13a, 14a) such that the plurality of fiber layers (13a, 14a) is arranged in such a way that it is stacked in the radial direction of a mandrel (1), wherein each of the fiber layer formation steps (S2, S3, S4) in order to form a respective fiber layer consisting of a corresponding fiber body and a corresponding first fixing element (13b, 14b) comprises: an arrangement step for arranging the corresponding fiber body with respect to an outer circumferential surface of the mandrel (1) such that the corresponding fiber body runs in an axial direction of the mandrel (1);and a fixing step (S5) for winding the corresponding first fixing element (13b, 14b), which is designed to fix the corresponding fiber body with respect to the outer circumferential surface of the mandrel (1), such that the corresponding first fixing element (13b, 14b) is wound with one or more turns in a circumferential direction along the axial direction of the mandrel (1) over the corresponding fiber body;and a forming step (S6), after the step of repeatedly repeating the fiber layer formation step (S2, S3, S4), for impregnating the fiber bodies of the plurality of fiber layers (13a, 14a) with a resin on the outer circumferential surface of the mandrel (1) and then heating the resin to form the resin, wherein the first fixing element (13b, 14b) of a lower from the plurality of fiber layers (13a, 14a) and the fiber body of an upper from the plurality of fiber layers (14a), which is located on the lower one, are stacked at least in the radial direction, and wherein each of the repeated fixing steps (S5) comprises arranging the first fixing element of the corresponding fiber layer in a different phase with respect to the first fixing elements arranged in the other fixing steps, in the axial direction of the mandrel, so that they do not overlap with the first fixing elements arranged in the other fixing steps are.; Manufacturing method of the tube body according to claim 3, wherein the fixing step further comprises fixing opposite end sections of the corresponding fiber body with respect to the outer circumferential surface of the mandrel (1) by a second fixing element (15).

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