robotic arm

Abstract

To provide a robot arm in which while a required high torsional strength is secured, weight is sufficiently light by attaching a functional portion to a main body portion of the robot arm, the main body portion being formed as a thermoplastic setting FRP made, cylindrical body, and safety is high as a robot arm operating among human beings, with a human being, or assisting a human being, and particularly to provide a robot arm having a high fixing strength in the mounting portion of a mounting member.SOLUTION: In a robot arm 5, a closed space 10 is provided in a fitting portion of an inner side surface 6b of an end portion of a thermoplastic setting FRP made, cylindrical body 6 and a mounting member 9, and a composite resin layer 8b formed by combining a thermoplastic resin and fiber is molded in this closed space 10 under pressure and heat; a mounting member 9 assembled by its being fitted in an inside diameter of the end portion of thermoplastic setting FRP made, cylindrical body 6 and the thermoplastic setting FRP made, cylindrical body 6 are fastened to each other with a bolt 11; and the composite resin layer 8a formed by combining a thermoplastic resin and fiber is molded on an outer side surface 6a of the end portion of the thermoplastic setting FRP made, cylindrical body 6 under pressure and heat.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a robot arm formed by pressurizing and heating a thermosetting resin and fiber composite resin onto at least one of the outer and inner surfaces of a thermosetting FRP cylindrical body. [Background technology]

[0002] Industrial robots used in laser processing, for example, typically require tip precision of approximately 1 / 100 mm, necessitating high rigidity. In recent years, however, with the declining birthrate and aging population, there has been a growing need for industrial robots that can work alongside or assist humans. These industrial robots do not require the high rigidity of conventional industrial robots; rather, lightweight construction is strongly desired for energy conservation and environmental conservation. One approach to achieving this goal has been to replace the robot arm body with a cylindrical thermosetting fiber reinforced plastic (FRP). Various reinforcing fibers, such as carbon fiber, glass fiber, and aramid fiber, have been considered. Among these, CFRP (carbon fiber-reinforced plastics), which uses carbon fiber as the reinforcing fiber, is considered particularly promising due to its superior specific strength and specific modulus.

[0003] This robot arm, whose main body is a cylindrical body made of thermosetting FRP, needs to be able to perform various functions by attaching functional parts to the main body. To attach the functional parts to the main body made of this cylindrical body made of thermosetting FRP, a joining method that balances the torsional strength of the cylindrical body made of thermosetting FRP is required.

[0004] Patent Document 1 discloses a mechanical device component in which a metal joint is press-fitted into the end of an FRP cylinder, with the objective of providing a structure that ensures the required high torsional strength while preventing damage from occurring at the end of the FRP cylinder due to the press-fit joining operation of the metal joint and also preventing the progression of deterioration in that area. The mechanical device component is an FRP cylinder and a metal joint press-fitted into the end of the FRP cylinder, and is characterized by having a slit machined in the axial direction from the end face of the FRP cylinder. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-103032 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the mechanical device component disclosed in Patent Document 1 had a problem in that it was not possible to obtain sufficient strength, particularly in the joints where other members were attached to the FRP cylinder that constituted the robot arm. Conventionally, FRP cylinders that constituted robot arms were generally made by cutting an FRP cylinder about 3 m thick to a predetermined length, and fixing members for attaching other members to the inside of both ends of the cut FRP cylinder. In this case, the mounting member was press-fitted into the mounting member fitting portion formed on the inside of the end of the FRP cylinder, and then the bolt was inserted through the mounting member fitting portion from the outside of the end of the FRP cylinder and tightened with the bolt, but this did not provide sufficient fixing strength. In such a case, even if a measure is taken such as applying an adhesive to the fitting portion of the mounting member before press-fitting the mounting member, the adhesive may run off, resulting in unstable fixing strength.

[0007] In view of the problems with the prior art described above, the object of the present invention is to provide a robot arm that has a main body made of a cylindrical thermosetting FRP body, on which a functional part is attached, thereby ensuring the required high torsional strength, and that is sufficiently lightweight and highly safe for use among humans, together with humans, or in assisting humans, and in particular, has strong fixing strength at the mounting parts of the mounting members. [Means for solving the problem]

[0008] That is, the robot arm according to the present invention is characterized in that it is made by pressurizing and heating a resin composite of thermosetting resin and fiber onto at least one of the outer and inner surfaces of a cylindrical body made of thermosetting FRP.

[0009] The robot arm according to the present invention is characterized in that it is made by pressurizing and heating a resin composite of thermosetting resin and fiber onto at least one of the outer and inner surfaces of the end of a cylindrical body made of thermosetting FRP.

[0010] Furthermore, the robot arm according to the present invention is a robot arm in which an attachment member is attached to the inner diameter of the end of a thermosetting FRP cylindrical body, and is characterized in that an attachment part that fits inside the end of the thermosetting FRP cylindrical body is formed by pressurizing and heating a resin that is a composite of thermosetting resin and fiber onto the inner surface of the end of the thermosetting FRP cylindrical body.

[0011] In addition, the robot arm of the present invention is a robot arm in which an attachment member is fitted to the inner diameter of the end of a thermosetting FRP cylindrical body, and is characterized in that it is made by pressurizing and heating a resin composite of thermosetting resin and fiber onto the outer surface of the end of the thermosetting FRP cylindrical body.

[0012] Furthermore, the robot arm according to the present invention is a robot arm in which an attachment member is fitted to the inner diameter of the end of a thermosetting FRP cylindrical body, and is characterized in that a closed space is provided at the fitting portion between the inner surface of the end of the thermosetting FRP cylindrical body and the attachment member, and a resin composite of thermosetting resin and fiber is pressurized and heated to form into this space.

[0013] Furthermore, the robot arm of the present invention is characterized in that the mounting member is fitted and assembled to the inner diameter of the end of a thermosetting FRP cylindrical body, and the thermosetting FRP cylindrical body is fastened to the mounting member with screws, and a resin composite of thermosetting resin and fiber is pressurized and heated to form on the outer surface of the end of the thermosetting FRP cylindrical body.

[0014] The method for manufacturing a robot arm of the present invention is characterized by comprising an inner diameter lamination process for forming a composite resin layer on the outer surface of a mounting member; a preforming and solidifying process; a press-fitting process for press-fitting and joining the mounting member, which has been subjected to the preforming and solidifying process and has a fiber-molded raw material placed on the outer surface, into the inside of the end of a thermosetting FRP cylindrical body; a bolting process for fastening the mounting member, which has been press-fitted and joined to the inside of the end of the thermosetting FRP cylindrical body by the press-fitting process, to the thermosetting FRP cylindrical body with bolts; and an outer diameter lamination process for forming a composite resin layer on the outer surface of the thermosetting FRP cylindrical body.

[0015] It is preferable that the inner diameter laminating step and the preforming and solidifying step are carried out by placing a fiber forming raw material in a recess formed in the outer surface of the mounting member.

[0016] The outer lamination step is preferably carried out by winding a pressure tape around the outside of the fiber forming raw material wound around the outer surface of the thermosetting FRP cylindrical body, and then applying pressure to carry out the forming step.

[0017] For a thermosetting FRP cylindrical body, it is particularly preferable that the reinforcing fibers contain carbon fibers having excellent specific strength and specific modulus of elasticity, in terms of achieving high strength and torsional torque transmission characteristics. [Effects of the Invention]

[0018] The robot arm of the present invention can be a robot arm that is sufficiently lightweight and highly safe as a mechanical device that operates between humans, together with humans, or assisting humans, while ensuring the required high torsional strength, and in particular can be a robot arm with strong fixing strength at the mounting parts of the mounting members. [Brief explanation of the drawings]

[0019] [Figure 1] 1(a) is a conceptual diagram of a shaped raw fabric material used in the shaping method of the present invention, and FIG. 1(b) is a conceptual diagram of a woven fabric substrate constituting the shaped raw fabric material shown in FIG. [Figure 2] 1 is a perspective view of a robot arm according to an embodiment of the present invention; [Figure 3] FIG. 3 is a partial longitudinal cross-sectional view of the robot arm of FIG. 2. [Figure 4] FIG. 3 is a partial cross-sectional view of the robot arm of FIG. 2. [Figure 5] FIG. 4 is a perspective view showing the same part as the partial cross-sectional view of FIG. 3. [Figure 6] 10A to 10C are explanatory views of another embodiment of the manufacturing method for a robot arm of the present invention. [Figure 7] 10A to 10C are explanatory views of another embodiment of the manufacturing method for a robot arm of the present invention. [Figure 8] 10A to 10C are explanatory diagrams illustrating another embodiment of the manufacturing method for a robot arm according to the present invention. [Figure 9] 10A to 10C are explanatory views of another embodiment of the manufacturing method for a robot arm of the present invention. [Figure 10] 10A to 10C are explanatory diagrams illustrating another embodiment of the manufacturing method for a robot arm according to the present invention. [Figure 11] 10A to 10C are explanatory diagrams illustrating another embodiment of the manufacturing method for a robot arm according to the present invention. [Figure 12] 10A to 10C are explanatory views of another embodiment of the manufacturing method for a robot arm of the present invention. [Figure 13]1A to 1C are explanatory diagrams illustrating an embodiment of a manufacturing method for a robot arm according to the present invention. [Figure 14] 14 is a partial longitudinal sectional view of a robot arm according to another embodiment of the present invention. [Figure 15] FIG. 15 is a graph showing the results of measuring the safety factor when a load of 60 kgm of bending strength is applied to the robot arm 5 according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] The fiber material used to manufacture the robot arm according to the embodiment of the present invention will be described below. The robot arm according to the embodiment of the present invention is manufactured using a raw fabric material 1 shown in Fig. 1(a). As shown in Fig. 1(a), the raw fabric material 1 is formed by adhering a resin material 4, the main component of which is a thermosetting resin, to at least one surface of a textile substrate 3 containing a plurality of reinforcing fiber bundles 2.

[0021] The fabric substrate 3 is a bidirectional fabric made by weaving multiple reinforcing fiber bundles 2, which are aligned in one direction so that they are parallel to each other, in two perpendicular directions, as shown in Figure 1(b). Bidirectional fabrics have the advantages that they are easily deformed into a three-dimensional shape due to changes in the relative positions of the reinforcing fiber bundles 2, and that a laminated molding material having mechanical quasi-isotropy can be easily obtained with a small number of sheets. The reinforcing fiber bundles 2 may be carbon fiber bundles, graphite fiber bundles, glass fiber bundles, aramid fiber bundles, etc., and are preferably carbon fiber bundles. By using carbon fiber bundles, the mechanical properties of the final product, a fiber-reinforced resin molded article, can be improved.

[0022] The resin material 4 attached to the surface of the textile substrate 3 is primarily composed of a thermosetting resin that can bond the layers of the textile substrate 3. Examples of thermosetting resins include epoxy, urethane, and polyester. By using a resin material 4 that is primarily composed of a thermosetting resin, handling is improved when bonding the layers of the textile substrate 3 after laminating the forming raw fabric 1 and transforming it into a three-dimensional shape, and productivity is improved. The "primary component" here refers to the component that accounts for the largest proportion of the components that make up the resin material 4.

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows a robot arm 5 according to one embodiment of the present invention. The robot arm 5 is formed by injection molding an FRP cylinder 6, which is one form of a thermosetting FRP cylindrical body, with a resin that is a composite of thermosetting resin and fiber, and functional parts 7a and 7b, made of a composite resin that is a composite of thermosetting resin and fiber, are molded on the outer diameter sides of both ends of the FRP cylinder 6. The functional parts 7a and 7b function as, for example, joints with operating parts, gripping parts, joints, etc. (not shown).

[0024] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 2 shows a robot arm 5 according to one embodiment of the present invention. The robot arm 5 is formed by pressurizing and heating an FRP cylinder 6, which is one form of a thermosetting FRP cylindrical body, with a resin that is a composite of thermosetting resin and fiber, and functional parts 7a and 7b, made of a composite resin that is a composite of thermosetting resin and fiber, are molded on the outer diameter sides of both ends of the FRP cylinder 6. The functional parts 7a and 7b function as, for example, joints with operating parts, gripping parts, joints, etc. (not shown).

[0025] The robot arm 5 according to this embodiment is formed by pressurizing and heating composite resin layers 8a, 8b, which are a composite of thermosetting resin and fiber, on at least one of the outer surface 6a and the inner surface 6b of a cylindrical body 6 made of thermosetting FRP, as shown in Figures 3, 5, and 4.

[0026] Specifically, the robot arm 5 according to this embodiment is formed by pressurizing and heating resin layers 8a, 8b, which are a composite of thermosetting resin and fiber, on at least one of the outer surface 6a and the inner surface 6b of the end A of a cylindrical body 6 made of thermosetting FRP.

[0027] Furthermore, the robot arm 5 according to this embodiment is a robot arm 5 in which an attachment member 9 is attached to the inner diameter of the end A of the thermosetting FRP cylindrical body 6, and a composite resin layer 8b made of a thermosetting resin and fiber is pressurized and heated and molded onto the inner surface 6b of the end of the thermosetting FRP cylindrical body 6 to form a closed space 10, which is an attachment part that fits inside the end of the thermosetting FRP cylindrical body 6.

[0028] In addition, the robot arm 5 according to this embodiment is a robot arm 5 in which an attachment member 9 is fitted to the inner diameter of the end of a thermosetting FRP cylindrical body 6, and is formed by pressurizing and heating a composite resin layer 8a made of a thermosetting resin and fiber onto the outer surface 6a of the end of the thermosetting FRP cylindrical body 6.

[0029] Furthermore, the robot arm 5 according to this embodiment is a robot arm 5 in which an attachment member 9 is fitted to the inner diameter of the end of a thermosetting FRP cylindrical body 6, and a closed space 10 serving as an attachment portion is provided at the fitting portion between the inner surface 6b of the end of the thermosetting FRP cylindrical body 6 and the attachment member 9, and a composite resin layer 8b made of a thermosetting resin and fiber is pressurized and heated and molded into this closed space 10.

[0030] In addition, the robot arm 5 according to this embodiment is formed by fastening the thermosetting FRP cylindrical body 6 and the mounting member 9 fitted to the inner diameter of the end of the thermosetting FRP cylindrical body 6 with bolts 11, and by pressurizing and heating a composite resin layer 8a made of a composite of thermosetting resin and fiber onto the outer surface 6a of the end of the thermosetting FRP cylindrical body 6.

[0031] The manufacturing process of the robot arm 5 according to the above embodiment will be described below. First, an inner diameter lamination process is performed to form a composite resin layer 8b on the outer surface of the mounting member 9. As shown in Figure 6, the fiber-molded raw fabric material 1 is placed in a recess 10 formed on the outer surface of the mounting member 9. At this time, the ambient temperature is 20°C, and the workpiece temperature is about 30°C.

[0032] Next, the preforming and solidification process is carried out as shown in Figure 7. In the preforming process, the ambient temperature is set to 50°C, and the workpiece temperature is set to about 50°C. In the solidification process, the ambient temperature is set to -15°C, and the workpiece temperature is set to about -15°C. Next, the press-fitting process is carried out as shown in Figure 8. The press-fitting process is carried out by placing the fiber-molded raw material 1 in a recess 10 formed on the outer surface of the thermosetting FRP cylindrical body 6, and press-fitting the mounting member 9 that has undergone the preforming and solidification process. The ambient temperature during the press-fitting process is set to 20°C, and the workpiece temperature is set to about -15°C.

[0033] Next, a bolt tightening process is carried out as shown in Figure 9. In this bolt tightening process, the mounting member 9 that has been press-fitted and joined to the inside of the end of the thermosetting FRP cylindrical body 6 in the press-fitting process is fastened to the thermosetting FRP cylindrical body 6 with bolts 11. The ambient temperature in this bolt tightening process is set to 20°C, and the workpiece temperature is set to about 20°C.

[0034] Next, an outer diameter lamination process is carried out to form a composite resin layer 8a on the outer surface of the thermosetting FRP cylindrical body 6. In this outer diameter lamination process, first, a fiber forming raw material 1 is wound around the outer surface of the thermosetting FRP cylindrical body 6, as shown in Figure 10. At this time, the ambient temperature is 20°C, and the workpiece temperature is about 30°C. 11, an outer diameter pressure tape winding process is carried out in which a pressure tape 12 is wound around the outside of the fiber forming raw material 1 wound around the outer surface of the thermosetting FRP cylindrical body 6, and pressure is applied. At this time, the ambient temperature is 20°C, and the workpiece temperature is about 30°C.

[0035] In this state, the forming process is carried out as shown in Figure 12. The environmental temperature in this forming process is 80°C, and the temperature of the workpiece is maintained at about 80°C for 2 hours. Finally, the pressure tape is removed as shown in FIG. 13, completing the production of the robot arm 5 according to the embodiment of the present invention.

[0036] 14 shows a partial vertical cross section of a robot arm according to another embodiment of the present invention. The robot arm 5 of this embodiment is otherwise similar to the robot arm 5 of the above-described embodiment, but differs in that it is provided with an integrated connecting portion 8a which is a composite resin layer formed by injection molding with a fiber-composite resin, connecting the recess 9a of the mounting member 9 and the outer surface of the end of the thermosetting FRP cylindrical body 6 provided with the through hole 6a, to the through hole 6c of the thermosetting FRP cylindrical body 6 and the closed space 10 of the fitting portion of the mounting member 9.

[0037] FIG. 15 shows the results of measuring the safety factor when a load of bending strength 60 kgm is applied to the robot arm 5 according to the embodiment of the present invention. As shown in the figure, the thermosetting FRP cylindrical body 6 alone has a safety factor of 11.1, whereas when the mounting member 9 is simply press-fitted into the inside of the end of the thermosetting FRP cylindrical body 6, the safety factor is 0.5, and when the fiber molding raw material 1 is placed and molded on the inside of the end of the thermosetting FRP cylindrical body 6 but outside the mounting member 9, and on the outside of the end of the thermosetting FRP cylindrical body 6, the safety factor is 5.5. In contrast, the robot arm 5 according to the embodiment of the present invention, which is fastened with bolts 11 and molded with fiber molding raw material 1 placed inside and outside, achieved a safety factor of 9.0. [Explanation of symbols]

[0038] 5...Robot arm, 6...Thermosetting FRP cylindrical body, 7a, 7b...Functional parts, 8...Composite resin layer.

Claims

1. A method for manufacturing a robot arm in which an attachment member is fitted to the inner diameter of the end of a thermosetting FRP cylindrical body, the method comprising the steps of pressurizing and heating a resin composite of thermosetting resin and fiber onto the outer surface of the end of the thermosetting FRP cylindrical body, and pressurizing and heating the resin composite of thermosetting resin and fiber between the inner surface of the end of the thermosetting FRP cylindrical body and a recess in the attachment member, the resin composite of thermosetting resin and fiber being a shaped base material formed by adhering a resin material mainly composed of thermosetting resin to at least one surface of a woven fabric substrate containing a plurality of reinforcing fiber bundles, the shaped base material being placed in the recess in the attachment member and subjected to a preforming step, followed by a solidifying step, and a press-fitting step in which the attachment member that has been subjected to the preforming step and the solidifying step is pressed into the inside of the end of the thermosetting FRP cylindrical body to fit it.

2. 2. The method for manufacturing a robot arm according to claim 1, wherein a molding step is performed after the press-fitting step.

3. 2. The method for manufacturing a robot arm according to claim 1, wherein the ambient temperature in the preforming step is set to 50°C and the workpiece temperature is set to 50°C, the ambient temperature in the solidifying step is set to -15°C and the workpiece temperature is set to -15°C, and the ambient temperature in the pressing step is set to 20°C and the workpiece temperature is set to -15°C.

4. 2. A method for manufacturing a robot arm according to claim 1, wherein said thermosetting FRP cylindrical body and a mounting member fitted to the inner diameter of the end of said thermosetting FRP cylindrical body are fastened together with screws.

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