SHAPED PIPE BODY

A lower arm that is a shaped pipe body includes an outer layer and an inner layer that are each formed into a circular pipe shape from CFRP, and therefore, rigidity is ensured. Further, the lower arm includes a vibration damping layer disposed between the outer layer and the inner layer, and therefore, a vibration damping property is enhanced. Therefore, in a robot arm using the lower arm, rigidity is ensured, and the vibration damping property is enhanced.

DESCRIPTION OF EMBODIMENTS

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. Note that in the respective drawings, the same or the corresponding parts are assigned with the same reference signs, and the redundant description will be omitted.

FIG. 1is a perspective view of a picking robot including a robot arm using one embodiment of a shaped pipe body of the present invention. As shown inFIG. 1, a picking robot1includes a main body2, a robot arm3connected to the main body2, and a picking device4that is mounted to a tip end of the robot arm3. The picking robot1like this picks up and transfers an object (for example, a medicine, a foodstuff and the like) in a state in which the picking robot is suspended in a plant.

The main body2is made movable optionally within an x-y plane in an orthogonal coordinate system S in the drawing. An undersurface2sof the main body2is provided with a plurality of (three in this case) connecting portions2afor connecting upper arms5of the robot arm3, which will be described later, to the main body2.

The robot arm3has a plurality of (three in this case) upper arms (shaped pipe bodies)5each in a long cylinder shape. The upper arm5has a base end5athereof connected to the connecting portion2aof the main body2. Connection of the upper arm5and the main body2is performed via a connecting member6that is mounted to the base end5aof the upper arm5. The upper arm5is made rotatable around the base end5ain a state in which the upper arm5is connected to the main body2.

Further, the robot arm3has a plurality (six in this case) of lower arms (shaped pipe bodies)7each in a long cylinder shape. The lower arm7shows a cylindrical shape with a diameter smaller than the upper arm5. The lower arm7has a base end7athereof connected to a tip end5bof the upper arm5. Here, the two lower arms7are connected to the one upper arm5. Connection of the lower arm7and the upper arm5is performed via a connecting member8that is mounted to the tip end5bof the upper arm5, and a connecting member9that is mounted to the base end7aof the lower arm7.

The picking device4is mounted to a tip end7bof the lower arm7via a connecting member10. The picking device4picks up an object by, for example, vacuum suction or the like. In the picking robot1, the main body2moves within the x-y plane while the upper arm5rotates, and thereby the picking device4can be moved to an optional position within an x-y-z space.

FIG. 2is a perspective view schematically showing a configuration of the lower arm7, andFIG. 3is a sectional view taken along the line ofFIG. 2. As shown inFIG. 2andFIG. 3, the lower arm7has an outer layer71formed into a circular pipe shape, an inner layer72that is formed into a circular pipe shape, and is disposed in an inner side of the outer layer71to extend from the one end71aof the outer layer71to the other end71bof the outer layer71, and a vibration damping layer73that is disposed between the outer layer71and the inner layer72. Namely, in the lower arm7, the vibration damping layer73is laminated on the inner layer72to cover the inner layer72in a circular pipe shape, and the outer layer71is laminated on the vibration damping layer73to cover the vibration damping layer73. Note that the one end71aof the outer layer71is the base end7aof the lower arm7, and the other end71bof the outer layer71is the tip end7bof the lower arm7. The lower arm7may be in the circular pipe shape in which an outside diameter and an inside diameter are not changed from the base end7athereof to the tip end7b, or may be in a taper shape in which the outside diameter and the inside diameter are made smaller toward the tip end7bfrom the base end7athereof. In a case of the lower arm being formed into the taper shape, the diameter thereof is made smaller toward the tip end7b, that is, a weight of the tip end7bside of the lower arm7is made small, and thereby, the vibration damping property can be improved.

The outer layer71and the inner layer72are formed from carbon fiber reinforced plastics (hereinafter, called “CFRP: Carbon Fiber Reinforced Plastics”). More specifically, the outer layer71and the inner layer72are produced by laminating a plurality of layers of the carbon fiber prepregs (for example, six layers for the outer layer71, and five layers for the inner layer72) formed by impregnating carbon fiber layers containing carbon fiber oriented in a predetermined direction with a matrix resin (for example, an epoxy resin) and thermally curing the carbon fiber prepregs.

The vibration damping layer73is formed from a viscoelastic material with rigidity lower than the rigidity of the CFRP composing the outer layer71and the inner layer72. A storage elastic modulus at 25° of the viscoelastic material of the vibration damping layer73is preferably in a range of 0.1 MPa or more and 2500 MPa or less, is more preferably in a range of 0.1 MPa or more and 250 MPa or less, and is further more preferably in a range of 0.1 MPa or more and 100 MPa or less. If the storage elastic modulus of the viscoelastic material is 2500 MPa or less, a sufficient vibration damping performance can be obtained, and if the storage elastic modulus is 0.1 MPa or more, reduction of the rigidity of the lower arm7is small, and the performance required as an industrial component can be satisfied. Further, since the outer layer71and the inner layer72are produced by thermally curing the carbon fiber prepregs, the viscoelastic material of the vibration damping layer73is preferably stable to the heat which is generated at that time. Furthermore, the viscoelastic material of the vibration damping layer73is preferably excellent in adhesion to the matrix resins of the outer layer71and the inner layer72.

From the above viewpoints, the viscoelastic material composing the vibration damping layer73can be a flexible material as compared with the CFRP, such as rubber such as styrene-butadiene rubber (SBR), chloroprene rubber (CR), butyl rubber (IIR), nitrile rubber (NBR), and ethylene propylene rubber (EPM, EPDM), a polyester resin, a vinyl ester resin, a polyurethane resin, an epoxy resin in which an elastic modulus is reduced by adding rubber, elastomer or the like that is a polymer having a flexible chain, or the like.

Here, in the robot arm3, the upper arm5has a similar configuration as the lower arm7. That is, the upper arm5has an outer layer (outer layer51that will be described later) formed into a circular pipe shape, an inner layer that is formed into a circular pipe shape, and is disposed in an inner side of the outer layer to extend from the one end of the outer layer to the other end, and a vibration damping layer disposed between the outer layer and the inner layer. Namely, in the upper arm5, the vibration damping layer is laminated on the inner layer to cover the inner layer in the circular pipe shape, and the outer layer is laminated on the vibration damping layer to cover the vibration damping layer. Note that the one end of the outer layer in this case is the base end5aof the upper arm5, and the other end of the outer layer is the tip end5bof the upper arm5. The upper arm5may be in the circular pipe shape in which an outside diameter and an inside diameter are not changed from the base end5athereof to the tip end5b, or may be in a taper shape in which the outside diameter and the inside diameter are made smaller toward the tip end5bfrom the base end5a. In the case of the taper shape, the diameter thereof is made smaller toward the tip end5b, that is, a weight of the tip end5bside of the upper arm5is made smaller, and thereby, the vibration damping property can be improved.

The respective outer layer, the inner layer and the vibration damping layer of the upper arm5can be composed of the similar materials to the respective outer layer71, the inner layer72and the vibration damping layer73of the lower arm7. However, the outer layer and the inner layer of the upper arm5are composed by laminating a larger number of the carbon fiber prepregs than the outer layer71and the inner layer72of the lower arm7(for example, nine layers in the case of the outer layer, and seven layers in the case of the inner layer). Namely, since the upper arm5has a larger diameter than the lower arm, the upper arm5is configured to prevent collapsing fracture by being made thick by laminating a larger number of the carbon fiber prepregs than the lower arm. Thicknesses of the upper arm5and the lower arm7are set with a thickness/average diameter (=½ of the sum of the outside diameter and the inside diameter) made 0.05 or more as the guideline. Therefore, as the diameters of the upper arm5and the lower arm7are larger, the thicknesses thereof become larger.

FIG. 4is a plan view showing a structure of an end portion of the lower arm7. As shown inFIG. 4, at an end portion including the base end7aof the lower arm7(namely, the one end portion including the one end71aof the outer layer71), a spiral screw groove74is formed at predetermined pitches (spiral work is applied), and thereby, a male screw74ais provided. Meanwhile, the connecting member9is provided with a female screw9acorresponding to the male screw74a. Accordingly, the lower arm7and the connecting member9are bonded to each other with use of screwing of the male screw74aand the female screw9ain addition to bonding by an adhesive. Note that the screw groove74is formed to a depth reaching approximately two to three layers of the carbon fiber prepregs of the outer layer71, and does not reach the vibration damping layer73.

A sectional shape of the screw groove74shows a rectangular shape (U shape) in which a bottom portion74cthereof is in a substantially linear shape. Namely, the bottom portion74cof the screw groove74is flat. Therefore, when a certain stress occurs to the lower arm7, concentration of the stress onto one portion of the bottom portion74cof the screw groove74is avoided. As a result, fracture with the screw groove74as an origin is prevented.

Further, at an end portion including the tip end7bof the lower arm7(namely, the other end portion including the other end71bof the outer layer71), the spiral screw groove74is also formed at predetermined pitches, and thereby, a male screw74bis provided. The connecting member10is provided with a female screw10bcorresponding to the male screw74b. Accordingly, the lower arm7and the connecting member10are bonded by using screwing of the male screw74band the female screw10bin addition to bonding by an adhesive.

FIG. 5is a plan view showing a structure of the upper arm5. As shown inFIG. 5, the outer layer51in the base end5aand the tip end5bof the upper arm5is also provided with male screws52aand52bsimilarly to the outer layer71in the base end7aand the tip end7bof the lower arm7. Namely, at an end portion including the base end5aof the upper arm5(namely, the one end portion including the one end51aof the outer layer51), a spiral screw groove52is formed at predetermined pitches, and thereby, the male screw52ais provided. The connecting member6is provided with a female screw6acorresponding to the male screw52a. Accordingly, the upper arm5and the connecting member6are bonded with use of screwing of the male screw52aand the female screw6ain addition to bonding by an adhesive. Note that a sectional shape of the groove52also shows a rectangular shape (U shape) in which a bottom portion52cthereof is in a substantially linear shape similarly to the groove74.

Furthermore, at an end portion including the tip end5bof the upper arm5(namely, the other end portion including the other end51bof the outer layer51), the spiral screw groove52is formed at the predetermined pitches, and thereby, the male screw52bis provided. The connecting member8is provided with a female screw8bcorresponding to the male screw52b. Accordingly, the upper arm5and the connecting member8are bonded with use of screwing of the male screw52band the female screw8bin addition to bonding by an adhesive.

Note that as the materials of the connecting members6,8,9and10, for example, a metallic material such as an aluminum alloy, a titanium alloy, and SUS, for example, can be used, and from the viewpoints of reduction in weight and reduction in cost, use of an aluminum alloy is especially preferable. Further, as the adhesive for use in bonding the respective arms and the respective connecting members, a room temperature setting adhesive, and a thermosetting adhesive of epoxy, polyurethane and the like can be used.

As described above, the lower arm7includes the outer layer71and the inner layer72which are each formed into a circular pipe shape from CFRP, and therefore, rigidity is ensured. Further, the lower arm7includes the vibration damping layer73disposed between the outer layer71and the inner layer72, and therefore, the vibration damping property is enhanced. Consequently, in the robot arm3using the lower arm7, rigidity is ensured, and the vibration damping property is enhanced.

Further, in the lower arm7, the vibration damping layer73shows the circular pipe shape, and therefore, the vibration damping property is isotropically enhanced with respect to circumferential directions of the outer layer71and the inner layer72. Further, in the lower arm7, the vibration damping layer73extends from the one end71aof the outer layer71to the other end71b(namely, from the base end7aof the lower arm7to the tip end7b), and therefore, the vibration damping property is further enhanced.

Further, the upper arm5also includes the outer layer51and the inner layer which are each formed into a circular pipe shape by the CFRP, and the vibration damping layer disposed between the outer layer51and the inner layer. Accordingly, in the robot arm3further using the upper arm5in addition to the lower arm7, higher rigidity is ensured, and the vibration damping property is further enhanced.

Further, in the lower arm7, the outer layer71is formed into the circular pipe shape from the CFRP. Therefore, higher rigidity as compared with the shaped pipe body of a metal is ensured. Further, in the lower arm7, for example, at the one end portion including the one end71aof the outer layer71, the male screw74ais provided. Therefore, by providing the female screw9aat the connecting member9, screwing of the male screw74aand the female screw9acan be used in addition to bonding with the adhesive, at the time of bonding to the connecting member9. Consequently, according to the lower arm7, bonding to the connecting member can be reinforced. With respect to the upper arm5, bonding to the connecting member also can be reinforced while rigidity is ensured similarly to the lower arm7. Accordingly, connection of the main body2and the upper arm5, connection of the upper arm5and the lower arm7and connection of the lower arm7and the picking device4can be reinforced.

Further, in the lower arm7, the sectional shape of the screw groove74is a rectangular shape, and therefore, the bottom portion74cthereof is flat. Therefore, when a certain stress occurs to the lower arm7, concentration of the stress onto one portion of the bottom portion74cof the screw groove74is avoided. As a result, fracture with the screw groove74as the origin is prevented. With respect to the upper arm5, fracture with the screw groove52as the origin is also prevented similarly to the lower arm7.

Further, in the lower arm7, the inner layer72is also formed into the circular pipe shape from the CFRP, and therefore, higher rigidity is ensured. Further, in the lower arm7, the vibration damping layer73is disposed between the outer layer71and the inner layer72, and therefore, the vibration damping property is enhanced. With respect to the upper arm5, rigidity is ensured, and the vibration damping property is enhanced, because the upper arm5has the similar configuration to the lower arm7.

Further, in the lower arm7, the vibration damping layer73is formed into the circular pipe shape, and therefore, the vibration damping property is isotropically enhanced with respect to the circumferential directions of the outer layer71and the inner layer72. Further, in the lower arm7, the vibration damping layer73is disposed between the outer layer71and the inner layer72to extend from the one end71aof the outer layer71to the other end71b(namely, from the base end7aof the lower arm7to the tip end7b), and therefore, the vibration damping property is further enhanced.

In the above embodiment, one embodiment of the shaped pipe body of the present invention is described, and the shaped pipe body of the present invention is not limited to the upper arm5and the lower aim7described above. For example, as shown inFIG. 6, the sectional shape of the screw groove74can be made a trapezoidal shape (inverted trapezoid shape) which is narrowed toward an interior of the outer layer71with the bottom portion74cbeing in a substantially linear shape. In this case, the bottom portion74cof the screw groove74is flat, and therefore, concentration of a stress onto one portion of the bottom portion74cof the screw groove74is avoided. As a result, fracture with the screw groove74as an origin is prevented. Note that a sectional shape of the screw groove52can be made an inverted trapezoid shape similar to the screw groove74in this case.

Further, in the lower arm7, the vibration damping layer73can be made to have a mode as shown inFIG. 7. As shown inFIG. 7, the vibration damping layer73is disposed between the outer layer71and the inner layer72so as to extend from the one end71aof the outer layer71to a predetermined position (position at a length of ⅔ of an entire length of the outer layer71in this case) between the one end71aand the other end71b. Namely, the vibration damping layer73extends from the base end7aof the lower arm7to the position at a length of approximately ⅔ of the entire length of the lower arm7. As above, the vibration damping layer73is kept within the predetermined range at the base end7aside of the lower arm7, whereby the vibration damping property is enhanced, and reduction of rigidity is restrained. Note that for the upper arm5, the vibration damping layer thereof also may have a similar configuration to that of the vibration damping layer73shown inFIG. 7.

Further, the lower arm7can be made to have a mode shown inFIG. 8. The lower arm7shown inFIG. 8has an outer layer81formed into a circular pipe shape, an inner layer82that is formed into a circular pipe shape and is disposed in an inner side of the outer layer81so as to extend from the one end of the outer layer81to the other end, an intermediate layer83that is formed into a circular pipe shape and is disposed between the outer layer81and the inner layer82so as to extend from the one end of the outer layer81to the other end, and two vibration damping layers84and85that are disposed between the outer layer81and the inner layer82. The vibration damping layer84is disposed between the outer layer81and the intermediate layer83, and the vibration damping layer85is disposed between the intermediate layer83and the inner layer82.

Namely, in the lower arm7, the vibration damping layer85is laminated on the inner layer82to cover the inner layer82in the circular pipe shape, the intermediate layer83is laminated on the vibration damping layer85to cover the vibration damping layer85, the vibration damping layer84is laminated on the intermediate layer83to cover the intermediate layer83, and the outer layer81is laminated on the vibration damping layer84to cover the vibration damping layer84. Note that the one end of the outer layer81is the base end7aof the lower arm7, and the other end of the outer layer81is the tip end7bof the lower arm7.

The outer layer81, the inner layer82and the intermediate layer83can be composed of a similar material to that of the outer layer71and the inner layer72described above. Further, the vibration damping layer84and the vibration damping layer85can be composed of a similar material to the vibration damping layer73described above. The lower arm7which is configured as above is used in the robot arm3, and thereby, the vibration damping property can be further enhanced while higher rigidity is ensured.

As an example of the shaped pipe body of the present invention, a test shaped pipe body corresponding to the lower arm7was prepared. The specification of the test shaped pipe body is as shown in the following Table 1. Note that in the following tables including Table 1, “laminated angle” indicates an angle between a longitudinal direction of each of the shaped pipe bodies and an orientation direction of the carbon fiber. The laminated angle of 0° indicates the longitudinal direction of each of the shaped pipe bodies, the laminated angle of 90° indicates a circumferential direction of each of the shaped pipe bodies, and the laminated angles of ±45° indicate bias directions. Further, in the following tables, “Ply” represents the number of prepreg layers, and “MPT” represents a thickness of one prepreg layer.

As shown in Table 1, in the test shaped pipe body, as the inner layer72, two layers of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 90°, and three layers of carbon fiber prepreg (carbon fiber prepreg E6025E-26K made by JX Nippon Oil & Energy Corporation) with the laminated angle of 0° were used.

Further, in the test shaped pipe body, as the outer layer71, two layers of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 90°, and four layers of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 0° were used. Moreover, in the test shaped pipe body, as the vibration damping layer73, an SBR sheet (made by Ask Industries Co., Ltd., trade name: Asner Sheet) was used. The SBR sheet as the vibration damping layer73was disposed from the base end of the test shaped pipe body to the tip end (namely, throughout the entire length of the test shaped pipe body).

The carbon fiber prepregs and the SBR sheet as above were laminated by being wound on a cylindrical core material of aluminum or the like in the sequence of Table 1, and thermally cured while the carbon fiber prepregs were fixed by a heat-shrinkable tape of PP, PET or the like being wound thereon from the outer side of the carbon fiber prepregs, after which, the core material was extracted, whereby the test shaped pipe body in a cylindrical shape with an inside diameter of 10.47 mm, an outside diameter of 14.00 mm, and a length of 900 mm was obtained.

Meanwhile, as a comparative example of the test shaped pipe body, the comparison shaped pipe body was prepared as follows. The specification of the comparison shaped pipe body is as shown in the following Table 2. Namely, the comparison shaped pipe body differs from the test shaped pipe body in that the comparison shaped pipe body does not have a layer corresponding to the vibration damping layer73. The carbon fiber prepregs were laminated by being wound on a cylindrical core material in the sequence of Table 2, and thermally cured while the carbon fiber prepregs were fixed by a heat-shrinkable tape of PP, PET or the like being wound thereon from the outer side of the carbon fiber prepregs, after which, the core material was extracted, whereby the comparison shaped pipe body in a cylindrical shape with an inside diameter of 10.77 mm, an outside diameter of 14.00 mm, and a length of 900 mm was obtained.

The vibration damping properties of the test shaped pipe body and the comparison shaped pipe body which were prepared as above were evaluated. The evaluation method of the vibration damping properties of the test shaped pipe body and the comparison shaped pipe body is as follows. First, as shown inFIG. 9, a holding member A made of aluminum is prepared. The holding member A is composed of a base section A1in a planar shape (a width of 100 mm, a height of 100 mm, and a thickness of 10 mm), and a holding section A2in a columnar shape that is provided to protrude from a substantially central portion of the base section A1. An outside diameter of the holding section A2is set to be substantially the same as the inside diameter of the test shaped pipe body.

Subsequently, a tip end portion of the holding section A2is inserted into the test shaped pipe body by approximately 50 mm from the one end portion of the test shaped pipe body, and in this state, the test shaped pipe body and the holding section A2are bonded by an adhesive. Subsequently, the base section A1is fixed to a fixed wall. Thereby, the test shaped pipe body is in a cantilever beam state.

Subsequently, a weight of 1 kg is suspended at the other end portion (tip end portion) of the test shaped pipe body. Subsequently, the string for suspending the weight is cut, and thereby the test shaped pipe body is caused to generate free vibration.

Subsequently, displacement of the tip end portion of the test shaped pipe body during free vibration is measured with a laser displacement gauge. By the above steps, a damping free vibration waveform shown inFIG. 10was obtained. Note that since the reflection of the laser of the laser displacement gauge varied due to the fact that the test shaped pipe body is in the cylindrical shape, a light plate was mounted to the tip end portion of the test shaped pipe body, and the plate was used as the target for the laser.

Similar steps were performed for the comparison shaped pipe body, and a damping free vibration waveform shown inFIG. 11was obtained. Note that the outside diameter of the holding section A2was set to be substantially the same as the inside diameter of the comparison shaped pipe body.

As shown inFIG. 10andFIG. 11, in the test shaped pipe body, displacement (arm tip end deflection in the drawings) of the tip end portion due to vibration was damped more quickly as compared with the comparison shaped pipe body. Accordingly, it has been confirmed that the vibration damping property is enhanced by providing the vibration damping layer composed of SBR between the inner layer and the outer layer composed of CFRP.

As another example of the shaped pipe body of the present invention, a test shaped pipe body corresponding to the upper arm5was prepared. The specification of the test shaped pipe body is as shown in the following Table 3.

As shown in Table 3, in the test shaped pipe body, as the inner layer, two layers of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 90°, one layer of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of −45°, one layer of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 45°, and three layers of carbon fiber prepreg (carbon fiber prepreg E24N33C269 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 0° were used.

Further, in the test shaped pipe body, as the outer layer51, one layer of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of −45°, one layer of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 45°, three layers of carbon fiber prepreg (carbon fiber prepreg B24N33C269 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 0°, two layers of carbon fiber prepreg (plain-woven carbon fiber prepreg FMP61-2026A made by JX Nippon Oil & Energy Corporation) with the laminated angle of 0°/90°, and two layers of carbon fiber prepreg (carbon fiber prepreg B24N35R125 made by JX Nippon Oil & Energy Corporation) with the laminated angle of 90° were used.

Further, in the test shaped pipe body, as the vibration damping layer, an SBR sheet (made by Ask Industries Co., Ltd., trade name: Asner Sheet) was used. Note that in the test shaped pipe body, the SBR sheet was disposed in a range from the base end of the test shaped pipe body to the position of a length of ⅔ of the entire length of the test shaped pipe body.

The carbon fiber prepregs and the SBR sheet as above were laminated by being wound on a cylindrical core material in the sequence of Table 3, and thermally cured while the carbon fiber prepregs were fixed by a heat-shrinkable tape of PP, PET or the like being wound thereon from the outer side of the carbon fiber prepregs, after which, the core material was extracted, whereby the test shaped pipe body in a cylindrical shape with an inside diameter of 48.52 mm, an outside diameter of 55.00 mm, and a length of 300 mm was obtained.

Meanwhile, as a comparative example of the test shaped pipe body, the comparison shaped pipe body was prepared as follows. The specification of the comparison shaped pipe body is as shown in the following Table 4. Namely, the comparison shaped pipe body differs from the test shaped pipe body described above in that the comparison shaped pipe body does not have a layer corresponding to the vibration damping layer. The carbon fiber prepregs were laminated by being wound on a cylindrical core material in the sequence of Table 4, and thermally cured while the carbon fiber prepregs were fixed by a heat-shrinkable tape of PP, PET or the like being wound thereon from the outer side of the carbon fiber prepregs, after which, the core material was extracted, whereby the comparison shaped pipe body in a cylindrical shape with an inside diameter of 48.82 mm, an outside diameter of 55.00 mm, and a length of 300 mm was obtained.

In the test shaped pipe body which was prepared as above, the vibration damping property is enhanced more as compared with the corresponding comparison shaped pipe body.

As an example of the shaped pipe body of the present invention, the test shaped pipe body was prepared as follows. More specifically, a lamination configuration thereof was made similar to the lamination configuration shown in Table 3. However, in the test shaped pipe body, the SBR sheet as the vibration damping layer was disposed from the base end of the test shaped pipe body to the tip end (namely, throughout the entire length of the test shaped pipe body). The SBR sheet and the carbon fiber prepregs as above were laminated in a plurality of layers by being wound on a cylindrical core material in the sequence of Table 3, and thermally cured while the carbon fiber prepregs were fixed by a heat-shrinkable tape of PP, PET or the like being wound thereon from the outer side of the carbon fiber prepregs, after which, the core material was extracted, whereby the CFRP shaped pipe body in a cylindrical shape with an inside diameter of φ49 mm, an outside diameter of φ55.48 mm, a thickness of 3.24 t and a length of 100 mm was shaped. Thereafter, the shaped pipe body was adjusted to have an outside diameter of φ55 mm by centerless grinding. Subsequently, a spiral screw groove was formed at pitches of 5 mm on the surface (outer layer) of the one end portion of the CFRP shaped pipe body, whereby a male screw was provided, and a test shaped pipe body20shown inFIG. 12was obtained. The concrete specification of a male screw21of the test shaped pipe body20was a protruded portion of φ55 mm (tolerance of −0.05 mm to −0.10 mm), a recessed portion of φ54 mm (tolerance of −0.05 mm to −0.10 mm), and a groove depth of 0.5 mm.

The male screw21was formed with the procedure of ordinary screw cutting. More specifically, after the CFRP shaped pipe body was shaped as described above, a cutting tool was moved at a predetermined speed along the longitudinal direction of the CFRP shaped pipe body while the CFRP shaped pipe body was set on a lathe and rotated, whereby the male screw21was formed. Note that instead of the cutting tool, a disk-shaped grindstone may be used.

Meanwhile, a bonding member25in a cylindrical shape with an outside diameter of φ80 mm and a thickness of 20 mm was produced of aluminum. On an inner side of the bonding member25, a female screw26was formed to be able to be screwed onto the male screw21of the test shaped pipe body20. The concrete specification of the female screw26was a groove pitch of 5 mm, a protruded portion of φ54 mm (tolerance of +0.15 mm to +0.10 mm), a recessed portion of φ55 mm (tolerance of +0.15 mm to +0.10 mm), and a groove depth of 0.5 mm. After an adhesive was applied to the male screw21of the test shaped pipe body20and the female screw26of the bonding member25, the bonding member25was screwed onto the male screw21of the test shaped pipe body20, and the adhesive was heated and cured.

As a comparative example of the test shaped pipe body20, a comparison shaped pipe body30shown inFIG. 13was prepared. The comparison shaped pipe body30differs from the test shaped pipe body20in that the comparison shaped pipe body30does not have a male screw. Meanwhile, a bonding member35that is bonded to the comparison shaped pipe body30was prepared. The bonding member35differs from the bonding member25in that the bonding member35does not have a female screw. After an adhesive was applied to a bonding portion (namely, a surface of the one end portion) of the comparison shaped pipe body30and a bonding portion (namely, an inner surface) of the bonding member35, the one end portion of the comparison shaped pipe body30was inserted into the bonding member35, and the adhesive was heated and cured.

As another comparative example of the test shaped pipe body20, a comparison shaped pipe body40shown inFIG. 14was prepared. The comparison shaped pipe body40differs from the test CFRP pipe20in that the comparison shaped pipe body40has a recessed and protruded portion41instead of the male screw21. The recessed and protruded portion41was formed by providing a plurality of grooves circumferentially on a surface of the one end portion of the CFRP shaped pipe body. The concrete specification of the recessed and protruded portion41was a groove pitch of 5 mm, a protruded portion of φ55 mm (tolerance of −0.05 mm to −0.10 mm), a recessed portion of φ54 mm (tolerance of −0.05 mm to −0.10 mm), and a groove depth of 0.5 mm.

Meanwhile, a bonding member45that is bonded to the comparison shaped pipe body40was prepared. The bonding member45differs from the bonding member25in that the bonding member45has a recessed and protruded portion46instead of the male screw. The concrete specification of the recessed and protruded portion46was a groove pitch of 5 mm, a protruded portion of φ55 mm (tolerance of +0.15 mm to +0.10 mm), a recessed portion of φ56 mm (tolerance of +0.15 mm to +0.10 mm), and a groove depth of 0.5 mm. After an adhesive was applied to the recessed and protruded portion41of the comparison shaped pipe body40and the recessed and protruded portion46of the bonding member45, the comparison shaped pipe body40was inserted in the bonding member45, and the adhesive was heated and cured.

For bonding of the respective shaped pipe bodies and the respective bonding members, as the adhesive, a two-liquid mixing type epoxy adhesive made by Nagase ChemteX Corporation (base resin: AW-106, curing agent: HV-953U) was used. Further, in bonding of the respective shaped pipe bodies and the respective bonding members, the respective shaped pipe bodies and the respective bonding members were kept in a heating furnace that was kept at 60° C. for about one hour in order to cure the adhesive.

The bonding strength of the test shaped pipe body20and the bonding member25which were prepared as above, the bonding strength of the comparison shaped pipe body30and the bonding member35, and the bonding strength of the comparison shaped pipe body40and the bonding member45were evaluated by a punching test. In the punching test, the test speed was 1 mm/minute. The evaluation result is as shown in Table 5 as follows. According to the result of Table 5, the bonding strength (breaking load) of the test shaped pipe body20and the bonding member25was the highest. Accordingly, it has been confirmed that by using screwing of the screws for bonding of the shaped pipe body of CFRP and the bonding member of aluminum, the bonding strength is enhanced.

INDUSTRIAL APPLICABILITY

According to the present invention, the shaped pipe body capable of ensuring rigidity of the robot arm and enhancing the vibration damping property, and the shaped pipe body capable of reinforcing bonding to the connecting member while ensuring rigidity can be provided.

REFERENCE SIGNS LIST