Robot arm and manufacturing method of robot arm

Abstract

To provide a robot arm having high safety in which a functional part is attached to a main body part of the robot arm formed as a cylindrical tube body made of a thermosetting FRP while securing required high torsion strength, which is sufficiently light-weighted and yet operates together with workers or operates while assisting the workers, between the workers, where fixing strength of a mounting part of a mounting member is strong in particular.SOLUTION: A robot arm 5 is manufactured through the steps of: providing resin filled parts 10a and 10b on an inner side surface 6b at an end part of a cylindrical tube body 6 made of a thermosetting FRP and in a fitting region of a mounting member 9; forming a complex resin layer 8b having thermosetting resin combined with fiber on the resin filled parts 10a and 10b by pressing and heating; and molding a complex resin layer 8a having thermosetting resin combined with fiber on an outer side surface 6a at the end part of the cylindrical tube body 6 made of the thermosetting FRP, by pressing and heating.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a robot arm formed by injecting and molding an epoxy resin added with a curing agent on the outer and inner surfaces of a cylindrical body made of thermosetting FRP.

Background Art

[0002] Generally, for example, an industrial robot used for laser processing or the like requires a tip accuracy of about 1 / 100 mm, and for this purpose, high rigidity is required. On the other hand, in recent years, with the progress of the declining birthrate and aging population, the need for industrial robots that operate with, assist, or alongside humans has been increasing. Such industrial robots do not require the high rigidity of conventional industrial robots. Rather, from the viewpoints of energy conservation and global environmental protection, weight reduction is strongly desired. As one means, replacing the main body part of the robot arm with a cylindrical body made of thermosetting FRP has been studied. At that time, there are various reinforcing fibers to be used. For example, carbon fibers, glass fibers, aramid fibers, etc. have been studied. Among these, in particular, CFRP (carbon fiber reinforced plastics) using carbon fibers, which are excellent in terms of specific strength and specific elastic modulus, as the reinforcing fiber is considered promising.

[0003] It is necessary to be able to attach functional parts to the main body part of this robot arm formed of a cylindrical body made of thermosetting FRP so that various functions can be performed. For attaching functional parts to the main body part made of this cylindrical body made of thermosetting FRP, a joining method that takes into account the torsional strength and balance of the cylindrical body made of thermosetting FRP is required.

[0004] Patent Document 1 aims to provide a robot arm that is lightweight, highly safe for humans to operate with, assist humans, or work alongside humans, while ensuring the required high torsional strength. The robot arm has a main body portion made of a thermosetting FRP cylindrical tube, with functional parts attached to the main body portion. In particular, it aims to provide a robot arm with a strong fixing strength at the attachment part of the attachment member. A closed space is provided at the fitting part between the inner surface of the end of the thermosetting FRP cylindrical tube and the attachment member, and a composite resin layer obtained by compounding a thermosetting resin and fibers is pressure-heat formed in this closed space, and the attachment member assembled by fitting to the inner surface of the end of the thermosetting FRP cylindrical tube and the thermosetting FRP cylindrical tube are bolted together. In addition, a robot arm is disclosed in which a composite resin layer obtained by pressure-heat forming a composite of a thermosetting resin and fibers is formed on the outer surface of the end of the thermosetting FRP cylindrical tube.

[0005] Patent Document 2 aims to obtain a joining method and a joining structure for tubular members that can uniformly fill an adhesive into an adhesive filling space with a simple configuration. An adhesive filling space is provided at the joining part between a first annular member and a second annular member. A porous member having elasticity is sandwiched between the insertion end of the second tubular member and a locking part provided on the inner diameter side of the first tubular member. The gap between the end of the first tubular member and the outer peripheral surface of the second tubular member is sealed with a sealing material. Then, an adhesive is injected from an adhesive injection port communicating with the adhesive filling space, and the air in the adhesive filling space is discharged through the porous member to join the two tubular members. A joining method and a joining structure for tubular members are disclosed.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, in the robotic arm disclosed in Patent Document 1, since it is simply a joined body formed by fitting a mounting member inside a cylindrical cylinder made of thermosetting FRP and subjecting a resin obtained by compounding a thermosetting resin and fibers to pressure heating molding, the compressive force is small and the joining strength is not yet sufficient. Also, since it is a structure formed by simply arranging a resin obtained by compounding a thermosetting resin and fibers in a recess formed on the outer surface of a cylindrical cylinder made of thermosetting FRP at the root part of the mounting member and subjecting it to pressure heating molding, the joining strength is not yet sufficient. As a countermeasure, in the robotic arm disclosed in Patent Document 1, after press-fitting a mounting member into a mounting member fitting portion formed inside the end of a cylindrical cylinder made of thermosetting FRP, a bolt is inserted through the mounting member fitting portion from the outside of the end of the cylindrical cylinder made of thermosetting FRP to perform bolt tightening. However, even then, the joining strength was not yet sufficient. In that case, for example, even if a countermeasure of applying an adhesive to the mounting member fitting portion and then press-fitting the mounting member is adopted, problems such as the adhesive flowing out and the joining strength becoming unstable occur. Also, between the mounting member and the first composite resin layer and between the mounting member and the second composite resin layer, a gap (about 0.1 mm) is generated due to the difference in expansion rate between the composite resin layer and the mounting portion (metal) in the first and second moldings, which has been the cause of the decrease in joining strength.

[0008] Also, in the joining method of a tubular member and the joining structure of a tubular member disclosed in Patent Document 2, after assembling an FRP cylindrical cylinder, an adhesive is injected through a hole processed on the outside of the FRP cylindrical cylinder. However, in such a structure, it can be easily estimated that a manufacturing apparatus (such as a mold) is required to maintain high sealing performance in order to prevent the outflow of the adhesive. Therefore, it is not easy to suppress the leakage of the adhesive, it is difficult to increase the filling pressure of the adhesive, and it is difficult to fill every corner of the gap in the adhesive filling portion.

[0009] In view of the problems in the above prior art, while ensuring the required high torsional strength, a functional part is attached to the main body part of a robot arm whose main body part is a cylindrical barrel made of thermosetting FRP, and it is sufficiently lightweight and safe as a robot arm that operates among humans, with humans, or assisting humans. In particular, an object of the present invention is to provide a robot arm having a strong fixing strength at the attachment part of the attachment member of the functional part and a method for manufacturing the robot arm.

Means for Solving the Problems

[0010] That is, the robot arm according to the present invention is a robot arm in which an attachment member is fitted and assembled inside the end of a cylindrical barrel made of thermosetting FRP, and a resin filling region is provided in the boundary region between the inner surface of the end of the cylindrical barrel made of thermosetting FRP and the attachment member at the fitting portion of the inner surface of the end of the cylindrical barrel made of thermosetting FRP and the attachment member, and resin is injected through a through hole formed in the side portion of the cylindrical barrel made of thermosetting FRP into this resin filling region and molded.

[0011] A ring-shaped groove can be provided on the inner surface of the end of the cylindrical barrel made of thermosetting FRP and the fitting side end of the attachment member at the fitting portion of the inner surface of the end of the cylindrical barrel made of thermosetting FRP and the attachment member, and resin can be poured in and molded for assembly.

[0012] Resin can be injected through the through hole formed in the side portion of the cylindrical barrel made of thermosetting FRP, and a predetermined amount of the resin injected through the through hole formed in the opposite side portion of the cylindrical barrel made of thermosetting FRP can be allowed to flow out, and filling can be confirmed and molded.

[0013] The resin injected through the through hole formed in the side portion of the cylindrical barrel made of thermosetting FRP into the resin filling region may be an epoxy resin added with a curing agent.

[0014] The attachment member can be made of metal.

[0015] The thermosetting FRP cylindrical body can be made of CFRP or GFRP.

[0016] The mounting member can be formed by winding a fiber forming base material around a fitting portion and subjecting it to pressure heating molding.

[0017] The mounting member can be inserted and fitted inside the thermosetting FRP cylindrical body, and a fiber forming base material can be wound around the circumferential side surface of the mounting member and the outer peripheral surface of the tip portion of the thermosetting FRP cylindrical body between the tip of the thermosetting FRP cylindrical body and the side surface of the mounting member, and pressure heating molding can be performed.

[0018] The mounting member can be inserted and fitted inside the thermosetting FRP cylindrical body, and a fiber forming base material can be wound around a recess formed between the tip of the thermosetting FRP cylindrical body and the side surface of the mounting member, and pressure heating molding can be performed.

[0019] Moreover, the method for manufacturing a robotic arm according to the present invention includes an inner lamination step of forming a composite resin layer on the outer surface of a mounting member by arranging a fiber preform impregnated with epoxy resin in a plurality of recesses formed on the outer surface of the mounting member, a first molding step of molding the fiber preform arranged in the recesses by pressurizing and heating to form a first composite resin layer, a step of forming a through-hole in the side portion of the thermosetting FRP cylindrical body, an assembly fitting step of press-fitting and fitting a mounting member having the first composite resin layer formed therein inside the end portion of the thermosetting FRP cylindrical body, and then, in a state where the mounting member is press-fitted and fitted, an inner diameter molding first step of providing an annular groove on the inner surface of the end portion of the thermosetting FRP cylindrical body and the fitting side end portion of the mounting member at the fitting portion between the inner surface of the end portion of the thermosetting FRP cylindrical body and the mounting member and pouring and molding epoxy resin, an inner diameter molding second step of filling the resin filling portion with epoxy resin through the through-hole, an outer lamination step of winding a fiber preform around the outer surface of the thermosetting FRP cylindrical body, and a second molding step of pressurizing and heating the fiber preform wound around the outer surface of the thermosetting FRP cylindrical body to cure the epoxy resin of the fiber preform and form a second composite resin layer.

[0020] In the first inner diameter molding step, it is possible to fill the gap formed between the end face of the thermosetting FRP cylindrical body and the mounting member in a state where the mounting member is press-fitted and fitted with epoxy resin.

[0021] In the second inner diameter molding step, it is possible to inject resin through the through-hole formed in the side portion of the thermosetting FRP cylindrical body and allow a predetermined amount of the injected resin to flow out through the through-hole formed in the side portion on the opposite side of the thermosetting FRP cylindrical body to confirm filling.

Advantages of the Invention

[0022] According to the robot arm and the method for manufacturing the robot arm of the present invention, it is possible to obtain a robot arm that is sufficiently lightweight while ensuring the required high torsional strength and is highly safe as a mechanical device that operates among humans, with humans, or assisting humans. In particular, it is possible to obtain a robot arm in which the fixing strength of the attachment portion of the attachment member is strong.

Brief Description of the Drawings

[0023]

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Embodiments for Carrying Out the Invention

[0024] The fiber material used for manufacturing the robotic arm according to the embodiment of the present invention will be described below. The robotic arm according to the embodiment of the present invention is manufactured using the fiber preform 1 shown in Fig. 1(a). As shown in Fig. 1(a), the fiber preform 1 is formed by attaching a resin material 4 mainly composed of a thermosetting resin to at least one surface of a fabric base material 3 including a plurality of reinforcing fiber bundles 2.

[0025] The fabric base material 3 is a bi-directional fabric formed by weaving a plurality of reinforcing fiber bundles 2 aligned in one direction so as to be parallel to each other as shown in Fig. 1(b) in two directions perpendicular to each other. The bi-directional fabric has the advantages that it is easily deformed due to changes in the relative positions between the reinforcing fiber bundles 2 and is easily deformed into a three-dimensional shape, and it is easy to obtain a laminated molded material having mechanical pseudo-isotropy with a small number of sheets. As the reinforcing fiber bundle 2, a carbon fiber bundle, a graphite fiber bundle, a glass fiber bundle, an aramid fiber bundle, etc. can be used, and a carbon fiber bundle is preferably used. By using a carbon fiber bundle, the mechanical properties of the fiber-reinforced resin molded product, which is the final product, can be made high.

[0026] The resin material 4 attached to the surface of the fabric base material 3 is mainly composed of a thermosetting resin capable of obtaining the effect of adhering between the layers of the fabric base material 3. As the thermosetting resin, for example, an epoxy resin can be used. By using a resin material 4 mainly composed of a thermosetting resin, the handleability when laminating the fiber preform 1 and deforming it into a three-dimensional shape and then adhering between the layers of the fabric base material 3 is improved, and the productivity is improved. Note that the main component is the component having the largest proportion among the components constituting the resin material 4.

[0027] The embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the robot arm 5 according to an embodiment of the present invention. The robot arm 5 is formed by pressure-heat molding a cylindrical body 6 made of thermosetting FRP, which is a form of a cylindrical body made of thermosetting FRP, with a resin obtained by compounding a thermosetting resin and fibers, and metal functional parts 7a and 7b are attached to the outer surface sides at both ends of the FRP cylindrical body 6. The functional parts 7a and 7b function as joints with, for example, operating parts, gripping parts, joint parts, etc. (not shown).

[0028] The robot arm 5 according to this embodiment is formed by pressure-heat molding composite resin layers 8a and 8b obtained by compounding a thermosetting resin and fibers on the outer surface 6a and the inner surface 6b of the end of the thermosetting FRP cylindrical body 6 as shown in FIGS. 3 and 4.

[0029] Furthermore, the robot arm 5 according to this embodiment is a robot arm 5 in which a mounting member 9 is assembled inside the end of the thermosetting FRP cylindrical body 6, and a resin filling part 10a, which is a mounting part that fits inside the end of the thermosetting FRP cylindrical body 6 by pressure-heat molding a composite resin layer 8b obtained by compounding a thermosetting resin and fibers on the inner surface 6b of the end of the thermosetting FRP cylindrical body 6, is formed.

[0030] That is, a resin filling part 10a is provided at the fitting part between the inner surface of the end of the thermosetting FRP cylindrical body and the mounting member. The thermosetting FRP cylindrical body 6, which is a pipe, is made of CFRP or GFRP. The mounting member 9, which is a flange, is made of metal. Insert a flange 9 formed by winding CFRP around the outer surface fitting part inside the pipe 6, provide a resin filling part 10a, which is a gap, at the fitting part, inject an epoxy resin with a curing agent added into the resin filling part 10a, and mold it to obtain a joined body of the pipe 6 and the flange 9. Furthermore, insert the flange 9 inside the pipe 6, wind the base of the fitting part between the outer surface of the pipe 6 and the flange 9 with CFRP and mold it to obtain the joined body, which is the robot arm 5 according to this embodiment. This resin filling portion 10a is a resin filling area provided in the boundary region between the inner surface of the end portion of the thermosetting FRP cylindrical body 6 and the mounting member 9 at the fitting portion of the inner surface of the end portion of the thermosetting FRP cylindrical body 6 and the mounting member 9. As will be described later, an epoxy resin injection process is performed in this resin filling area to form a resin filling portion by injecting epoxy resin through a through hole previously formed in the side surface of the thermosetting FRP cylindrical body.

[0031] The manufacturing process of the robot arm 5 according to the above embodiment will be described below. First, an inner lamination process for forming the composite resin layer 8b on the outer surface of the mounting member 9 is performed. As shown in FIG. 5, a fiber molding preform 1 in which carbon fibers are impregnated with epoxy resin is placed in a plurality of recesses 11 (resin filling portions 10a) formed on the outer surface of the mounting member 9.

[0032] Next, as shown in FIG. 6, a molding process is performed. This molding process is performed by pressing the fiber molding preform 1 in which carbon fibers are impregnated with epoxy resin and placed in the recess 11 (resin filling portion 10a) with a split mold 12 and holding it at 80°C for 2 hours. As a result, the epoxy resin of the fiber molding preform 1 is cured. Thereby, the composite resin layer 8b is formed. Thereafter, as shown in FIG. 7, a filling space cutting process is performed. In the filling space cutting process, the composite resin layer 8b formed in the previous process is cut to form a space and a gap for filling epoxy resin in a later process to form the resin filling portion 10a. In this process, the edge portion 8c of the composite resin layer 8b is left, and the cutting operation is performed so that a step of 0.15 mm is generated between the top edge portion 8d of the edge portion 8c and the flat portion 8e on the inner side of the edge portion 8c of the composite resin layer 8b.

[0033] On one hand, as shown in FIG. 8, two through holes 13 penetrating from one side to the other side of the side portion of the thermosetting FRP cylindrical body 6 are formed in the side portion of the thermosetting FRP cylindrical body 6. The position where the through hole 13 is formed is such that one through hole 13a is located inside the end portion of the thermosetting FRP cylindrical body 6 in the assembling and fitting process described later, and corresponds to the side portion of the thermosetting FRP cylindrical body 6 where the resin filling portion 10a is located in a state where the mounting member 9 having the composite resin layer 8b formed on the outer surface is press-fitted and fitted. On the other hand, the other through hole 13b is located inside the end portion of the thermosetting FRP cylindrical body 6 in the assembling and fitting process described later, and corresponds to the side portion of the thermosetting FRP cylindrical body 6 where the chamfered portion of the inner end portion of the mounting member 9 in the thermosetting FRP cylindrical body 6 is located in a state where the mounting member 9 having the composite resin layer 8b formed on the outer surface is press-fitted and fitted. Next, as shown in FIG. 9, an assembling and fitting process is performed. The assembling and fitting process is performed in a manner of press-fitting and fitting the mounting member 9 having the composite resin layer 8b formed on the outer surface inside the end portion of the thermosetting FRP cylindrical body 6. The environmental temperature in the assembling and fitting process is set to 20°C, and the workpiece temperature is set to about -15°C.

[0034] In that state, as shown in FIG. 10, the first inner diameter forming process is performed. This first inner diameter forming process is performed by injecting epoxy resin into the through hole 13b. As a result, the epoxy resin is filled into the gap, which is an annular groove formed between the chamfered portion of the inner end portion of the mounting member 9 in the thermosetting FRP cylindrical body 6 and the inner surface of the thermosetting FRP cylindrical body 6 in a state where the mounting member 9 is press-fitted and fitted. That is, in the first inner diameter forming process, the epoxy resin is filled into the gap 13c, which is an annular groove formed between the end face of the thermosetting FRP cylindrical body 6 and the mounting member 9 in a state where the mounting member 9 is press-fitted and fitted. As a result, in the first inner diameter forming process, the gap between the thermosetting FRP cylindrical body 6 and the mounting member 9, which serves as a path for the resin to leak when injecting the resin into the space for forming the resin filling portion 10a, is sealed.

[0035] Next, the second inner diameter forming process is performed. In this second inner diameter forming process, as shown in Fig. 11, the resin filling portion 10a is filled with epoxy resin through the through hole 13a. In this second inner diameter forming process, the injection of epoxy resin and the discharge of air from the recess 11 (resin filling portion 10a) are carried out, whereby the resin filling portion 10a is formed. Thereafter, by holding at room temperature for about 2 hours, the injected two-component epoxy resin cures. Note that by injecting the epoxy resin in this way, the resin can penetrate and fill the gap (about 0.1 mm) generated due to the difference in expansion rate during the molding process between the metal mounting member 9 and the composite resin layers 8a and 8b, and the bonding strength can be improved. Also, in the above second inner diameter forming process, resin is injected through the through hole 13a formed in the side portion of the thermosetting FRP cylindrical body 6, and the resin injected through the through hole 13a formed in the side portion on the opposite side of the thermosetting FRP cylindrical body 6 is allowed to flow out by a predetermined amount to confirm filling.

[0036] Next, an outer lamination process for forming the composite resin layer 8a on the outer surface of the thermosetting FRP cylindrical body 6 is performed. In this outer lamination process, the following points are considered. As shown in Fig. 9, with the mounting member 9 inserted inside the thermosetting FRP cylindrical body 6, a recess 9c is formed by the front end surface of the thermosetting FRP cylindrical body 6, the inner surface (one side surface) 9a of the mounting member 9 facing the front end surface, and the outer surface (the other side surface) 9b of the mounting member 9 intersecting the front end surface. Therefore, in the outer lamination process, first, the fiber forming base material 1 is wound and disposed in this recess 9c. The fiber forming base material 1 is adjusted to a size that fits into the recess 9c and used. Furthermore, in that state, as shown in Figs. 12, 13, and 14, the fiber forming base material 1 and the fiber forming base material 1 are wound around the outer surface of the thermosetting FRP cylindrical body 6. At this time, the environmental temperature is 20°C and the workpiece temperature is about 30°C. By winding and disposing the fiber forming base material 1 in the recess 9c in this way, voids can be eliminated, and the strength of the final product can be improved.

[0037] Subsequently, continue to perform the molding process as shown in FIGS. 12, 13, and 14. This molding process is carried out by pressing the fiber molding base material 1 impregnated with epoxy resin into the carbon fiber wound around the outer surface of the thermosetting FRP cylindrical body 6 with a split mold 12 and holding it at an environmental temperature of 80° C. and a workpiece temperature of 80° C. for 2 hours. As a result, the epoxy resin of the fiber molding base material 1 hardens. Thereby, the composite resin layer 8a is formed.

Explanation of Reference Numerals

[0038] 5... robot arm, 6... thermosetting FRP cylindrical body, 7a, 7b... functional parts, 8... composite resin layer.

Claims

1. A robot arm assembled by fitting and attaching a mounting member inside the end of a cylindrical body made of thermosetting FRP, wherein a resin filling region is provided in a boundary region between the inner surface of the end of the cylindrical body made of thermosetting FRP and the mounting member at the fitting portion of the inner surface of the end of the cylindrical body made of thermosetting FRP and the mounting member, and resin is injected into this resin filling region through a through hole formed in the side portion of the cylindrical body made of thermosetting FRP and molded, characterized in that it is a robot arm.

2. The robot arm according to claim 1, wherein a ring-shaped groove is provided at the fitting side end of the inner surface of the end of the cylindrical body made of thermosetting FRP and the mounting member at the fitting portion of the inner surface of the end of the cylindrical body made of thermosetting FRP and the mounting member, and resin is poured and molded for assembly.

3. The robot arm according to claim 1, wherein resin is injected through a through hole formed in the side portion of the cylindrical body made of thermosetting FRP, and a predetermined amount of the resin injected through a through hole formed in the side portion on the opposite side of the cylindrical body made of thermosetting FRP is allowed to flow out, and filling is confirmed and molded.

4. The robot arm according to claim 1, wherein the resin injected into the resin filling region through a through hole formed in the side portion of the cylindrical body made of thermosetting FRP is an epoxy resin added with a curing agent.

5. The robot arm according to claim 1, wherein the mounting member is made of metal.

6. The robot arm according to claim 1, wherein the cylindrical body made of thermosetting FRP is made of CFRP or GFRP.

7. The robot arm according to claim 1, wherein the mounting member is formed by winding a fiber molding stock around a fitting portion and subjecting it to pressure heating molding.

8. A robot arm according to claim 1, wherein the mounting member is inserted and fitted inside the thermosetting FRP cylindrical body, and a fiber molding stock is wound around the circumferential side surface of the mounting member and the outer peripheral surface of the tip portion of the thermosetting FRP cylindrical body between the tip of the thermosetting FRP cylindrical body and the side surface of the mounting member and subjected to pressure heating molding.

9. The robot arm according to claim 1, wherein the mounting member is inserted and fitted inside the cylindrical body made of thermosetting FRP, and a fiber preform is wound around a recess formed between the tip of the cylindrical body made of thermosetting FRP and the side surface of the mounting member, and is formed by pressure heating.

10. An inner lamination step of forming a composite resin layer on the outer surface of the mounting member by arranging a fiber preform impregnated with an epoxy resin in a plurality of recesses formed on the outer surface of the mounting member; a first forming step of forming a first composite resin layer by pressure heating and molding the fiber preform arranged in the recess; a step of forming a through hole in the side portion of the cylindrical body made of thermosetting FRP; an assembling and fitting step of press-fitting and fitting the mounting member having the first composite resin layer formed thereon inside the end portion of the cylindrical body made of thermosetting FRP; then, in a state where the mounting member is press-fitted and fitted, a ring-shaped groove is provided on the inner surface of the end portion of the cylindrical body made of thermosetting FRP and the fitting side end portion of the mounting member at the fitting portion between the inner surface of the end portion of the cylindrical body made of thermosetting FRP and the mounting member, and an inner diameter forming first step of pouring and molding an epoxy resin; an inner diameter forming second step of filling the resin filling portion with an epoxy resin through the through hole; an outer lamination step of winding a fiber preform around the outer surface of the cylindrical body made of thermosetting FRP; and a second forming step of pressure heating and curing the epoxy resin of the fiber preform wound around the outer surface of the cylindrical body made of thermosetting FRP to form a second composite resin layer. A method for manufacturing a robot arm, characterized by comprising the above steps.

11. The method for manufacturing a robot arm according to claim 10, wherein in the first inner diameter forming step, an epoxy resin is filled in a gap formed between the end face of the cylindrical body made of thermosetting FRP and the mounting member in a state where the mounting member is press-fitted and fitted.

12. The method for manufacturing a robot arm according to claim 10, wherein in the second inner diameter forming step, a resin is injected through a through hole formed in the side portion of the cylindrical body made of thermosetting FRP, and a predetermined amount of the resin injected through the through hole formed in the side portion on the opposite side of the cylindrical body made of thermosetting FRP is allowed to flow out for filling confirmation.

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