JP6522356B2 - Power transmission shaft - Google Patents

Description

  The present invention relates to a power transmission shaft, and more particularly to a power transmission shaft used for automobiles and various industrial machines.

  The power transmission shaft used in automobiles and various industrial machines is generally made of steel. However, such steel products are heavy. For this reason, in recent years, fiber reinforced plastics, such as CFRP (carbon fiber reinforced plastic), may be used for weight reduction.

  Thus, when using a fiber reinforced plastic, in order to prevent strength degradation, it becomes combined use with a steel member. For this reason, it becomes necessary to join a fiber reinforced plastic and a steel member, and there are some which considered bondability between this fiber reinforced plastic and a steel member conventionally (patent documents 1-patent documents 3).

  In Patent Document 1, at an end portion of a fiber reinforced plastic (FRP) tube body, a metal yoke is joined via a rivet. In this case, the FRP tube body is formed of a right-angled winding layer in which the orientation angle of the fiber is wound substantially at right angles to the central axis, and at the end, the orientation angle of the fiber is acute at the central axis The acute angle winding layer to be wound and the right angle winding layer are alternately disposed.

  In Patent Document 2, the end of the FRP cylinder interposes a helical winding layer in which the fiber orientation angle is less than 45 degrees with respect to the central axis, and a hoop winding layer interposed between the helical winding layers. It is In the hoop wound layer, the orientation angle of the fiber is set to 45 degrees or more and less than 90 degrees. Then, an intermediate cylindrical member formed of a metal plate is press-fit into this end portion, and further, a press-fit shaft portion of the metal yoke is fitted into the intermediate cylindrical member.

  In this case, serrations are formed on the outer diameter surface and the inner diameter surface of the intermediate cylindrical member, and when the intermediate cylindrical member is pressed into the end of the FRP cylinder, the serration on the outer diameter surface is the end of the FRP cylinder Bite into the inner diameter surface of the part. Further, by inserting the press-fit shaft portion of the metal yoke into the intermediate cylindrical member, the serration formed on the outer diameter surface of the press-fit shaft portion of the metal yoke is engaged with the serration of the inner diameter surface. Thus, the metal yoke is joined to the FRP cylinder.

  Patent Document 3 describes an FRP drive shaft formed by connecting metal end joints to both ends of an FRP cylinder. In this case, the end joint comprises a serration shaft member and a large diameter flange member coupled to the serration shaft member. Then, a metal butt collar made of a short cylindrical body having a corrugated engaging portion formed on the serration shaft member is externally fitted, and the end of the FRP cylinder is externally fitted on the serration shaft member It is.

  Further, a corrugated engaging portion is formed at an end of the FRP cylinder, and the corrugated engaging portions are fitted with each other in a state where the corrugated engaging portion of the butt collar abuts on the corrugated engaging portion. And the collar which consists of a short cylindrical body is fitted outside at the fitting site | part of this waveform engaging part. In this case, the corrugated engagement portion of the FRP cylinder and the corrugated engagement portion of the collar are fitted, and in that state, the collar is externally fitted and bonded to the fitted portion of the corrugated engagement portion. Then, a combination of the FRP cylinder and the butt collar is pressed into the serration shaft member.

Japanese Utility Model Application 1-91118 JP 2004-308700 A JP, 2011-52720, A

  In the patent document 1, as described above, a metal yoke is inserted into the end portion of the FRP tube body, and these are connected using a rivet. For this reason, when torque is applied, stress concentrates on the rivet penetration site, and there is a risk of breakage when relatively low torque occurs. Moreover, it is a thing using a rivet and it can not be said that it is excellent in assemblability and bondability.

  In Patent Document 2, the serration on the outer diameter surface side of the intermediate cylindrical member is bitten into the inner diameter surface of the end portion of the FRP cylinder, and the fibers on the inner diameter surface side of the FRP cylinder are cut by this biting. There is a risk of For this reason, peeling is apt to occur between FRP (fiber reinforced plastic) layers when torque is applied.

  In Patent Document 3, the waveform engaging portions are fitted to each other in a state in which the waveform engaging portion and the waveform engaging portion of the butt collar abut on the end of the FRP cylinder. However, also in this case, the serration of the serration shaft member bites into the inner diameter surface of the corrugated engagement portion at the end of the FRP cylinder. For this reason, there is a possibility that fibers on the inner diameter surface side of the FRP cylinder may be cut, as in the case of Patent Document 2 described above. In addition, there is no limitation on the fiber orientation direction of the FRP cylinder. For this reason, when a torque is applied, the fiber may be subjected to a force in the shear direction, and the strength is not stable.

  Therefore, the present invention provides a power transmission shaft capable of securing a high level of torsional strength of a fiber-reinforced plastic and achieving weight reduction.

The power transmission shaft of the present invention is a power transmission shaft for connecting a pair of constant velocity universal joints, and a metal short shaft connected to the bottom of the cup of the outer joint member of each constant velocity universal joint, A hollow fiber reinforced plastic shaft body is disposed between the short shaft portions, and the fiber reinforced plastic of the shaft body has directional fibers, and the end portions of each short shaft portion are circumferentially extended. Forming a triangular wave portion in which a plurality of triangular portions are disposed, and forming a triangular wave portion in which a plurality of triangular portions are disposed along the circumferential direction at both end portions of the shaft main body, The short shaft portion and the shaft in a state in which the shaft main body is interposed between a pair of short shaft portions by meshing in which the side of the short side of the triangular waveform on the short side and the side of the triangular shape on the shaft body contact with each other. a body are integrated linearly arranged, and the triangular waveform portion The round portion is formed on the point, the fiber orientation angle of the fiber reinforced plastic of the shaft body, as 30 ° to 60 ° and -30 ° to 60 °, the stress direction occurring hypotenuse of each triangular portion in the torque load state It is configured to be in the same direction. In this case, the fiber orientation angle is preferably 30 ° to 60 ° and -30 ° to -60 °, and more preferably ± 45 °. When the fiber orientation angle is 30 ° to 60 ° or -30 ° to -60 °, the angle formed by the oblique side of each triangular portion of the triangular waveform portion with respect to the shaft body axial center is 30 ° to 60 ° And -30 ° to -60 °.

  According to the power transmission shaft of the present invention, the diameter (outside diameter) of the hollow fiber reinforced plastic shaft body can be increased, and the fiber orientation angle of the fiber reinforced plastic of the shaft body can be controlled by torque The torsional strength of the fiber-reinforced plastic can be maintained at a high level by configuring it in the same direction as the stress direction generated on the oblique side of each triangular portion in the state. When the fiber orientation angle is 30 ° to 60 ° (-30 ° to -60 °), the angle formed by the oblique side of each triangular portion of the triangular wave portion with respect to the shaft body axial center is 30 ° to 60 °. By setting the angle (° to -30 ° to -60 °), the apex portion of the triangular portion forms a triangular shape of about 60 ° to 120 °, and the strength due to the shape is also stabilized. That is, if the apex is an acute angle of about 60 ° or less, the shape is so-called tapered and the strength due to the shape is not stable. Conversely, if the obtuse angle is 120 °, the axial length of the fitting portion becomes short It becomes difficult to exert a stable torque transmission function.

  The shaft body made of hollow fiber reinforced plastic may be internally fitted with a core metal, or may be covered with a protective pipe material. As a result, it is possible to strengthen the hollow fiber reinforced plastic shaft body against buckling and to improve the torsional strength.

  A ring-shaped collar member is externally fitted to the meshing portion where the triangular waveform portion meshes, or a sheet material obtained by impregnating fibers with resin is wound, or a fiber body obtained by impregnating resin is wounded be able to. By these, it can prevent that the meshing part which a triangular waveform part meshes engages in expansion (diameter expansion) to the outer diameter side at the time of a torque load.

  The fiber reinforced plastic of the shaft body may be impregnated with a large number of short fibers. By impregnating a large number of short fibers, the strength of the fiber reinforced plastic can be improved.

  The short shaft portion in which the triangular waveform portion is formed may be an integral molding with the outer joint member of the constant velocity universal joint.

  In the present invention, the torsional strength of the fiber reinforced plastic can be secured at a high level, and the strength due to the shape is also stable. For this reason, weight reduction can be achieved, and a power transmission shaft capable of effectively exhibiting a torque transmission function can be provided.

  In the case where the core metal is fitted to the shaft main body, it is possible to prevent the buckling of the shaft main body and to contribute to the improvement of the torsional strength. If it is covered with a protective pipe material, this protective pipe material can play a role as a core metal for reinforcing the torsional strength on the outer peripheral side of the shaft main body, and foreign substances from the outside (for example, stepping stones) Can be protected from ultraviolet light and the like.

  By externally fitting a collar member or the like to the meshing portion where the triangular waveform portion is meshed, expansion (diameter expansion) to the outer diameter side can be prevented at the time of torque load, bonding strength reduction can be prevented, and stability over a long period of time Torque transfer function can be exhibited.

  By impregnating a large number of short fibers, the strength of the fiber reinforced plastic can be improved, and a more durable power transmission shaft can be provided.

  In addition, if the short shaft portion is a single-piece product with the outer joint member, the connection operation of the short shaft portion can be omitted, and the assembly workability can be improved.

It is sectional drawing of the power transmission shaft of this invention. It is an enlarged view of the meshing part which the triangular waveform part of the power transmission shaft shown in the said FIG. 1 meshes. It is an enlarged view of the state which covered the color member in the meshing part which a triangular waveform part meshes. It is an enlarged view of the state which wound the sheet | seat which impregnated resin with the fiber which becomes 45 degrees in fiber orientation angle | corner in the meshing part. It is the top view of the power transmission shaft which wound the sheet | seat which impregnated resin with the fiber which becomes 90 degrees in fiber orientation angle | corner in the meshing part. It is sectional drawing of the power transmission shaft which shows other embodiment.

  Hereinafter, an embodiment of the present invention will be described based on FIGS. 1 to 6. The power transmission shaft is used, for example, in automobiles and various industrial machines, and is used as a drive shaft or the like.

  The drive shaft is formed by connecting a fixed type constant velocity universal joint 31 and a sliding type constant velocity universal joint 32 by a power transmission shaft 1 according to the present invention. In this example, a bar field constant velocity universal joint is used as the fixed constant velocity universal joint 31, and a tripod constant velocity universal joint is used as the sliding constant velocity universal joint 32.

  The fixed type constant velocity universal joint 31 has an outer joint member 35 in which a plurality of axially extending track grooves 33 are formed in the inner diameter surface 34 and a plurality of axially extending track grooves 36 in the outer diameter surface 37 in the circumferential direction. An inner joint member 38 formed at equal intervals, a plurality of balls 39 transmitting torque by being interposed between the track groove 33 of the outer joint member 35 and the track groove 36 of the inner joint member 38; The cage 40 is provided between the inner diameter surface and the outer diameter surface of the inner joint member to hold the ball.

  The sliding type constant velocity universal joint 32 has an outer joint member 52 in which three track grooves 51 extending in the axial direction are provided on the inner circumference and a roller guide surface 51 a facing each other is provided on the inner side wall of each track groove 51; A tripod member 54 having three leg shafts 53 projecting in the radial direction, an inner roller 55 externally fitted to the leg shaft 53, and an outer roller inserted in the track groove 51 and externally fitted to the inner roller 55 56 and the like. That is, the sliding constant velocity universal joint 32 is a double roller type in which the outer roller 56 is rotatable with respect to the leg shaft 53 and movable along the roller guide surface 51a. Further, the tripod member 54 includes a boss 57 and the leg shaft 53. The leg shaft 53 protrudes radially from the circumferential three-way position of the boss 57.

  The shaft end fitting portion of the shaft 61 is inserted into the shaft hole of the inner joint member 38 in the fixed type constant velocity universal joint 31 so that torque can be transmitted, and torque can be transmitted to the shaft hole of the tripod member 54 in the sliding type constant velocity universal joint. The shaft end fitting portion of the shaft 62 is inserted. The end portions of the both shaft end fitting portions of the shafts 61 and 62 are prevented from coming off by snap rings 65 and 65 such as snap rings. That is, circumferential grooves 66, 66 are formed at the end of the shaft end fitting portion, and the retaining rings 65, 65 are fitted in the circumferential grooves 66, 66.

  Male splines 67, 67 are formed on the outer diameter of the shaft end fitting portion of the shafts 61, 62, and female splines 68, 68 are formed in the shaft holes of the inner joint member 38 and the tripod member 54 of both constant velocity universal joints. It is formed. The male splines 67, 67 and the female splines 68, 68 are engaged by inserting the shaft end fitting portions of the shafts 61, 62 into the inner joint members 38 of the constant velocity universal joints 31, 32 and the shaft holes of the tripod member 54. Coupling together enables torque transmission between the shaft 61 and the inner joint member 38 and torque transmission between the shaft 62 and the tripod member 54.

  Boots 30A and 30B are mounted between the shafts 61 and 62 and the outer joint members 35 and 52, respectively, for preventing foreign matter from the outside and grease from the inside. The boots 30A and 30B include a large diameter end 30a, a small diameter end 30b, and a bellows 30c connecting the large diameter end 30a and the small diameter end 30b. The large diameter end 30a of the boot 30 is fastened and fixed by the boot bands 45A and 45B at the open end of the outer joint members 35 and 52, and the small diameter end 30b is fastened and fixed by the boot bands 46A and 46B at a predetermined portion of the shaft. There is.

  The power transmission shaft 1 includes metal short shafts 2A and 2B continuously connected to the cup bottoms 35a and 52b of the outer joint members 35 and 52 of the constant velocity universal joints 31 and 32, and the short shafts 2A and 2B. And a hollow fiber reinforced plastic shaft body 3 disposed therebetween. The fiber reinforced plastic of the shaft main body 3 is one having directional fibers.

  As shown in FIG. 2, the short shaft portions 2A and 2B are each formed with a triangular waveform portion 9 made of steel or the like in which a plurality of triangular portions 8 are disposed along the circumferential direction at one end side. The top of the triangular portion 8 of the triangular waveform portion 9 is rounded.

  The shaft body 3 is formed by, for example, a filament wand method. Here, the filament wandering method is a method in which a resin-impregnated reinforcing fiber is wound around a mandrel (hollow cylindrical mold) and molded and cured in a heat curing furnace to obtain a finished product. There are a method of rotating the mandrel side and a method of rotating a winding head called creel.

  For this reason, in the shaft main body 3, as shown in FIG. 1, the fiber reinforced plastic has directional fibers, and the first fiber winding portion M1 where the fiber orientation angle θ is + 45 ° The second fiber winding portion M2 has a fiber orientation angle θ of −45 °.

  Further, as shown in FIG. 2, at the end of the shaft main body 3, there is formed a triangular waveform portion 11 in which a plurality of triangular portions 10 are disposed along the circumferential direction. In this case, the triangular portion 10 forms an isosceles triangle that is 45 ° as an angle α that the oblique side 10a forms with the shaft axis in plan view. The top of the triangular portion 10 is rounded.

  In this case, as shown in FIG. 1, the outer diameter dimension D1 of the short shaft portions 2A and 2B and the outer diameter dimension D2 of the shaft main body 3 are set to the same dimension, and the thickness dimension T1 of the short shaft portions 2A and 2B and The thickness dimension T2 of the shaft body 3 is set to the same dimension.

  Then, a core metal 15 made of a pipe material is internally fitted to the shaft body 3. As the core metal 15, for example, steel for machine structure represented by S53C or S43C or the like, or 10B38 or the like in which boron is added to improve the quenching depth and strength can be used. In this case, it is preferable to perform the heat curing process to secure the strength, but if the outer diameter dimension can be set relatively large and the strength can be secured, the heat curing process is not performed. It may be. When hardening treatment is performed, the surface hardness is set to 52 HRC to 65 HRC. The thickness dimension of the core metal 15 is set smaller than the thickness dimension T2 of the shaft main body 3 in the illustrated example, but can be variously changed depending on the material used, and the thickness dimension of the core metal 15 and the shaft main body Alternatively, the thickness dimension of the core metal 15 may be made thicker than the thickness dimension T2 of the shaft main body 3.

  Bulges 41 and 41 are provided on the bottom wall portions 35a and 52a of the outer joint members 35 and 52 of the constant velocity universal joints 31 and 32, respectively, and both ends of the core metal 15 are formed on the bulges 41 and 41. The respective parts are externally fitted, and the core metal 15 is integrated with the bulging parts 41, 41 by joining means such as welding. The bulging portion 41 includes an outer diameter side large diameter portion 41a and an inner diameter side small diameter portion 41b. For this reason, the end face 6 of the core metal 15 is joined in a state where the end faces 42 and 42 of the large diameter portion 41 a of the bulging portion 41 abut on each other. Further, the end surface 7 of the short shaft portions 2A and 2B is also joined to the bottom wall portions 35a and 52a by a bonding means such as welding in a state where the end surfaces 42 and 42 abut on each other.

  Then, as shown in FIG. 2, the triangular portion 8 of the short shaft portions 2A and 2B and the triangular portion 10 of the shaft main body 3 have the same shape and dimensions and are arranged at the same pitch along the circumferential direction. . Therefore, the triangular portion 10 of the shaft main body 3 is fitted into the triangular recess 12 formed between the adjacent triangular portions 8 in the circumferential direction of the short shaft portions 2A and 2B. The triangular portion 8 of the short shaft portions 2A and 2B is fitted in the triangular recess 13 formed between the adjacent triangular portions 10 in the circumferential direction. That is, the triangular waveform portion 9 of the short shaft portions 2A and 2B and the triangular waveform portion 11 of the shaft main body 3 mesh with each other.

  In this case, the angles α and β of the oblique side 10a of the triangular portion 10 of the shaft body 3 and the oblique side 8a of the triangular portion 8 of the short shaft portions 2A and 2B are 45 °, and the first fiber winding portion of the shaft body 3 The fiber orientation angle θ of the (fibers wound in the A direction) is + 45 °, and the fiber orientation angle θ of the second fibers (the fibers wound in the B direction) is −45 °. , The direction of stress generated at the time of torque load and the direction of fibers are the same.

  Incidentally, the fiber orientation angle θ of the first fiber (A-direction fiber) of the shaft main body 3 is not limited to + 45 °, and may be + 30 ° to + 60 °, and the fiber of the second fiber (B-direction fiber) The orientation angle θ may be −30 ° to −60 °. Therefore, the angle β of the oblique side of the triangular portion 10 of the shaft main body 3 and the oblique side of the triangular portion 8 of the short shaft portions 2A and 2B is not limited to 45 °, but may be 30 ° to 60 °. . That is, it is only necessary to set so that the direction of stress generated at the time of torque load and the direction of fibers are the same.

  Further, as the resin of the shaft main body 3, even if it is a thermosetting resin such as epoxy resin, it can be a thermoplastic resin such as PA (nylon), PP (polypropylene), PEEK (polyether ketone), etc. .

  As the fiber reinforced plastic, when the fiber is impregnated through the resin layer in advance, the fiber layer is impregnated with a myriad of short fibers while being stirred into the resin layer, and the fiber to be wound (first fiber winding portion M1 and second The short fiber may be adhered to the fiber winding portion M2). As a result, not only long fibers wound in the cured resin but also innumerable short fibers are contained. In addition, as fiber length of a short fiber, it is less than 1 mm.

  Next, in FIG. 3, a collar member 16 formed of a short cylindrical body is externally fitted to the meshing portion S between the triangular waveform portion 9 of the short shaft portion 2A and the triangular waveform portion 11 of the shaft main body 3. The collar member 16 may be, for example, steel for machine structure represented by S53C or S43C, or 10B38 or the like which is improved in quenching depth and strength by adding boron. Furthermore, alloy steel such as stainless steel or non-ferrous metal such as aluminum alloy or resin for weight reduction may be used. Although not shown, the short shaft portion 2B may be fitted with the collar member 16 similarly.

  The collar member 16 is pressed into the meshing portion S between the triangular waveform portion 9 of the short shaft portions 2A and 2B and the triangular waveform portion 11 of the shaft main body 3 to cover the meshing portion S. Further, since this color member 16 is not a member for transmitting torque, even if the color member 16 is made of metal, it is not necessary to carry out a thermosetting process, but of course, a thermosetting process was carried out. It may be one. In the case of heat curing, the surface hardness is set to 52 HRC to 65 HRC. The thickness dimension of the collar member 16 is, for example, about 5 mm to 10 mm.

  In FIG. 4, instead of the collar member 16, a sheet material 17 impregnated with resin is wound around the meshing portion S of the triangular waveform portion 9 of the short shaft portion 2A and the triangular waveform portion 11 of the shaft main body 3. . In this case, as fibers, as in the fibers of the shaft main body 3, A-direction fibers having a fiber orientation angle θ of + 45 ° and B-direction fibers having a fiber orientation angle θ of −45 ° are provided. In FIG. 5, the fiber orientation direction of the sheet material 17 is a circumferential direction. Moreover, it may replace with the sheet material 17 which impregnated resin, and may wind the fibrous body formed by impregnating resin. Although not shown, the sheet 17 of FIGS. 4 and 5 may be wound around the fitting portion S also on the short shaft portion 2B.

  Next, the power transmission shaft shown in FIG. 6 is obtained by covering the outer periphery of the shaft main body 3 with a protective pipe member 20. The short shaft portions 2A and 2B are integrally connected to the bottom wall portions 35a and 52a of the outer joint members 35 and 52, respectively. And while the triangular-shaped part 10 of the shaft main body 3 fits into the triangular-shaped recessed part 12 formed between the adjacent triangular-shaped parts 8 of the circumferential direction of short axis part 2A, 2B, the circumference of the shaft main body 3 The triangular portion 8 of the short shaft portions 2A and 2B is fitted in the triangular recess 13 formed between adjacent triangular portions 10 in the direction. That is, the triangular waveform portions 9 of the short shaft portions 2A and 2B mesh with the triangular waveform portions 11 of the shaft main body 3 (see FIG. 2).

  And protection pipe material 20 is fitted on short axis parts 2A and 2B and shaft main part 3 outside. As the protective pipe member 20, for example, steel for mechanical structure represented by S53C or S43C, or 10B38 or the like, which is added boron to improve quenching depth and strength, is used similarly to the core metal 15. Can. Also in this case, it is preferable to perform the heat curing process to secure the strength, but if the outside diameter dimension can be set relatively large and the strength can be secured, the heat curing process is not performed. It may be. When hardening treatment is performed, the surface hardness is set to 52 HRC to 65 HRC.

  In a state in which both end portions 20a, 20a of the protective pipe member 20 are externally fitted to the short shaft portions 2A, 2B, the end surfaces thereof are butted to the end surfaces 43 of the bottom wall portions 35a, 52a of the outer joint members 35, 52. Both ends 20a, 20a of the protective pipe member 20 are joined and integrated with the short shaft portions 2A, 2B by joining means such as welding.

  In this case, the outer diameter D4 of the protective pipe member 20 and the outer diameter D5 of the bulging portions 41 and 41 of the outer joint members 35 and 52 are set to be the same, and the inner diameter D6 of the protective pipe 20 and The outer diameter dimension D2 of the shaft main body 3 is set to be the same. Also in this case, the outer diameter dimension D2 of the shaft 3 and the outer diameter dimension D1 of the short shaft portions 2A and 2B are set to the same dimension, and the thickness dimension T2 of the shaft 3 and the short shaft portions 2A and 2B The thickness dimension T1 is set to the same dimension. For this reason, the triangular waveform portion 9 of the short shaft portions 2A and 2B and the triangular waveform portion 11 of the shaft main body 3 mesh with each other. In this state, the protective pipe member 20 is externally fitted to the shaft body 3.

  In the power transmission shaft of the present invention, the diameter (outer diameter) of the hollow fiber reinforced plastic shaft main body 3 can be increased, and the fiber orientation angle of the fiber reinforced plastic of the shaft main body 3 can be controlled by torque The torsional strength of the fiber-reinforced plastic can be maintained at a high level by configuring it in the same direction as the stress direction generated on the oblique sides of the triangular portions 8 and 10 in the state. Further, by setting the angle of the oblique side of each triangular portion 8 or 10 of triangular waveform portion 9 or 11 with respect to the shaft body axis of the shaft to be 30 ° to 60 °, the apex portion of triangular portion 10 is A triangular shape of about 60 ° to 120 ° is formed, and the strength due to the shape is also stable. That is, if the apex is an acute angle of about 60 ° or less, the so-called tapered shape does not stabilize the strength due to the shape; conversely, if the obtuse angle is 120 °, the axial length of the meshing portion S becomes short. It becomes difficult to exert a stable torque transmission function.

  For this reason, in the present invention, the torsional strength of the fiber reinforced plastic can be secured at a high level, and the strength due to the shape is also stable. For this reason, weight reduction can be achieved, and a power transmission shaft capable of effectively exhibiting a torque transmission function can be provided. In particular, the angle formed by the oblique sides 8a and 10a of the triangular portions 8 and 10 of the triangular corrugated portions 9 and 11 with respect to the shaft body axial center is 45 °, and the fiber orientation angle of the fiber reinforced plastic of the shaft body 3 is By setting the angle to ± 45 °, there is an advantage that it is easy to set in the same direction as the stress generated on the oblique sides 8a and 10a of the triangular portions 8 and 11 in a torque load state.

  In the case where the core metal 15 is internally fitted to the shaft main body 3, it is possible to prevent the buckling of the shaft main body 3 and contribute to the improvement of the torsional strength. Further, by externally fitting the collar member 16 or the like to the meshing portion where the triangular waveform portions 9 and 11 mesh, expansion (diameter expansion) to the outer diameter side at the time of torque load can be prevented, and the bonding force is reduced. The torque transmission function can be exhibited stably over a long period of time.

  The one impregnated with a large number of short fibers can improve the strength of the fiber reinforced plastic, and can provide a more durable power transmission shaft.

  If it is covered with the protective pipe material 20, this protective pipe material 20 can exert the role as a core metal for reinforcing the torsional strength on the outer peripheral side of the shaft main body 3, and foreign substances from the outside It can be protected from (for example, stepping stones) or ultraviolet light.

  Although the embodiment of the present invention has been described above, the present invention can be variously modified without being limited to the above embodiment, and in the power transmission shaft, it is possible to avoid the buckling and secure the torsional strength. As long as it is possible to obtain the shaft main body 3 that can be made, the core metal 15 and the protective pipe member 20 may be omitted. Also, the fiber reinforced plastic of the shaft main body 3 may not be impregnated with short fibers.

  Further, the number, size and the like of the triangular portion 10 of the shaft main body 3 can be arbitrarily set according to the diameter dimension and the thickness dimension of the shaft main body 3 and the like. In the above embodiment, the top of each triangular portion 10 is rounded by forming a rounded portion, but such a rounded portion may not be provided.

  When the core metal 15 and the protective pipe member 20 are joined, friction welding (friction welding / pressure welding) may be used other than welding. Friction bonding is a bonding method in which relative movement is caused while contact pressure is applied to a metal material, and the generated frictional heat is used as a heat source. Moreover, when joining by welding, various welding methods, such as electron beam welding, laser welding, arc welding, or gas welding, are employable.

  Moreover, although the filament winding method was shown in the said embodiment as a manufacturing method of the shaft main body 3 which consists of fiber reinforced plastics, you may employ | adopt other methods, such as a sheet winding method. Here, the sheet winding method means that a sheet-like fiber is impregnated with a resin on the outside of a rotating mandrel, and a semi-cured one (prepreg) is wound and cured, and then the mandrel is pulled out to form a pipe. It is a method of molding things.

  As the fiber reinforced plastic, glass fiber reinforced plastic (GFRP) or carbon fiber reinforced plastic (CFRP) can be used, and further, boron fiber reinforced plastic (BFRP), aramid fiber reinforced plastic (AFRP, KFRP), polyethylene Fiber reinforced plastic (DFRP) etc. can also be used. Moreover, as a short fiber to be impregnated, glass fiber, carbon fiber, etc. can be used, but carbon nanotube (CNT), cellulose nanofiber (CNF), etc. may be used.

  The fixed type constant velocity universal joint 31 is not limited to the illustrated one, and even if it is an undercut free type constant velocity universal joint, the sliding constant velocity universal joint 32 is a double offset type, cross groove type It may be a constant velocity universal joint. Moreover, in the said embodiment, although used as a drive shaft as a power transmission shaft, you may use for propeller shafts other than a drive shaft. When a tripod type is used as the sliding constant velocity universal joint 32, it may be a single roller type or a double roller type.

S meshing portion 2A, 2B short shaft portion 3 shaft body 8, 10 triangular portion 9, 11 triangular waveform portion 15 core metal 16 color member 17 sheet material 20 pipe material for protection 31 fixed type constant velocity joint 32 sliding type etc. Fast joint

Claims (8)

A power transmission shaft connecting a pair of constant velocity universal joints,
A fiber of the shaft main body is provided with a metal short shaft continuously connected to the cup bottom of the outer joint member of each constant velocity universal joint, and a hollow fiber reinforced plastic shaft main body disposed between the short shafts. The reinforced plastic has directional fibers, and at the end of each short axis, forms a triangular corrugated portion in which a plurality of triangular portions are disposed along the circumferential direction, and both ends of the shaft main body The part forms a triangular waveform part in which a plurality of triangular parts are disposed along the circumferential direction, and the side of the triangular waveform part on the short axis side and the side of the triangular waveform part on the shaft main body The short shaft portion and the shaft main body are linearly arranged and integrated in a state in which the shaft main body is interposed between the pair of short shaft portions by meshing in contact, and a rounded portion is formed at the apex of the triangular waveform portion and, the fiber orientation angle of the fiber reinforced plastic of the shaft body, 30 ° ~ 0 ° and a -30 ° ~-60 °, the power transmission shaft, characterized by being configured such that the stress in the same direction occurring hypotenuse of each triangular portion in the torque load.   The power transmission shaft according to claim 1, wherein a core metal is internally fitted to the shaft body.   The power transmission shaft according to claim 1 or 2, wherein a ring-shaped collar member is externally fitted to a meshing portion at which the triangular wave portion meshes.   The power transmission shaft according to claim 1 or 2, wherein a sheet material formed by impregnating a fiber with a resin is wound around a meshing portion in which a triangular wave portion meshes.   The power transmission shaft according to claim 1 or 2, wherein a fiber body obtained by impregnating a resin is wound around a meshing portion in which a triangular wave portion meshes.   The power transmission shaft according to any one of claims 1 to 5, wherein the fiber reinforced plastic of the shaft main body is impregnated with a large number of short fibers.   The power transmission shaft according to any one of claims 1 to 6, wherein the short shaft portion in which the triangular waveform portion is formed is an integral molding with the outer joint member of the constant velocity universal joint.   The power transmission shaft according to claim 1, wherein the shaft body made of hollow fiber reinforced plastic and the meshing portion where the triangular wave portion meshes are covered with a protective pipe material.

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