WO2016125517A1

WO2016125517A1 - Power transmission shaft

Info

Publication number: WO2016125517A1
Application number: PCT/JP2016/050194
Authority: WO
Inventors: 卓板垣
Original assignee: Ntn株式会社
Priority date: 2015-02-03
Filing date: 2016-01-06
Publication date: 2016-08-11
Also published as: JP6522356B2; JP2016142363A

Abstract

The fiber-reinforced plastic of a shaft body has directional fibers and, on an end of short shaft sections, a triangular waveform section, which is obtained by disposing multiple triangular parts along the circumferential direction, is formed. On both ends of the shaft body, triangular waveform sections, which are obtained by disposing multiple triangular parts along the circumferential direction, are formed. The short shaft sections and the shaft body are linearly disposed and integrated in a configuration in which the shaft body is interposed between the pair of short shaft sections by an engagement such that the sides of the triangular waveform sections of the short shaft sections are in contact with the sides of the triangular waveform sections of the shaft body.

Description

Power transmission shaft

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

The power transmission shaft used for automobiles and various industrial machines is generally made of steel. However, such steel is 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 fiber reinforced plastic is used, it is used in combination with a steel member in order to prevent strength deterioration. For this reason, it is necessary to join the fiber reinforced plastic and the steel member. Conventionally, there are some which consider the bondability between the fiber reinforced plastic and the steel member (Patent Documents 1 to 3).

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

In Patent Document 2, the end portion of the FRP cylindrical body 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 has been made. In the hoop winding layer, the orientation angle of the fibers is 45 degrees or more and less than 90 degrees. Then, an intermediate cylindrical member formed of a metal plate is press-fitted into this end, and further, a press-fit shaft portion of a metal yoke is fitted into this intermediate cylindrical member.

In this case, serrations are formed on the outer diameter surface and inner diameter surface of the intermediate cylindrical member, and when the intermediate cylindrical member is press-fitted into the end portion of the FRP cylinder, the serration on the outer diameter surface side is the end of the FRP cylinder body. It bites into the inner diameter surface of the part. Further, when the press-fit shaft portion of the metal yoke is fitted 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 surface. Therefore, 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 includes a serration shaft member and a large-diameter flange member coupled to the serration shaft member. A metal butting collar made of a short cylindrical body having a corrugated engagement portion is externally fitted to the serration shaft member, and an end of the FRP cylinder is externally fitted to the serration shaft member. It is.

Also, a corrugated engagement portion is formed at the end of the FRP cylinder, and the corrugated engagement portions are fitted to each other in a state where the corrugated engagement portion of the abutting collar is abutted against the corrugated engagement portion. And the collar which consists of a short cylindrical body is externally fitted by 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 this state, the collar is externally fitted and bonded to the fitting portion of the corrugated engagement portion. Then, the FRP cylinder and the butt collar are integrated into the serration shaft member.

Japanese Utility Model Publication No.1-91118 JP 2004-308700 A JP 2011-52720 A

In Patent Document 1, as described above, a metal yoke is inserted into the end of an FRP tube body, and these are connected using a rivet. For this reason, when torque is applied, stress concentrates on the rivet penetrating portion, and there is a risk of breakage when relatively low torque is generated. Moreover, since rivets are used, it cannot be said that the assembling property and the joining property are excellent.

In Patent Document 2, serrations on the outer diameter surface side of the intermediate cylindrical member are 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. For this reason, peeling is likely to occur between FRP (fiber reinforced plastic) layers during torque loading.

In Patent Document 3, the corrugated engagement portions are fitted to each other in a state where the corrugated engagement portion and the corrugated engagement portion of the butting collar are butted against the end of the FRP cylinder. However, also in this case, the serration of the serration shaft member bites into the inner surface of the corrugated engagement portion at the end of the FRP cylinder. For this reason, there is a possibility that the fiber on the inner surface side of the FRP cylinder may be cut as in the case of Patent Document 2. There is no limitation on the fiber orientation direction of the FRP cylinder. For this reason, at the time of torque load, there exists a possibility that a fiber may receive force in a shearing direction, and it is not stable in strength.

Therefore, the present invention provides a power transmission shaft that can ensure the torsional strength of the fiber reinforced plastic at a high level and can be reduced in weight.

A power transmission shaft according to the present invention is a power transmission shaft for connecting a pair of constant velocity universal joints, and includes a metal short shaft portion connected to a cup bottom portion of an outer joint member of each constant velocity universal joint, It has a shaft body made of hollow fiber reinforced plastic disposed between the short shaft parts, and the fiber reinforced plastic of the shaft body has directional fibers, along the circumferential direction at the end of each short shaft part Forming a triangular corrugated portion in which a plurality of triangular portions are disposed, and forming a triangular corrugated portion in which a plurality of triangular portions are disposed along the circumferential direction at both ends of the shaft body, The short shaft portion and the shaft in a state where the shaft main body is interposed between the pair of short shaft portions by the meshing contact between the side of the triangular corrugated portion on the short shaft portion side and the side of the triangular waveform portion on the shaft main body side. The body is linearly arranged and integrated, and the shaft body The fiber orientation angle of the fiber-reinforced plastic, which is constituted such that the stress in the same direction occurring hypotenuse of each triangular portion in the torque load. In this case, the fiber orientation angles are 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 with respect to the shaft main axis of the hypotenuse of each triangular portion of the triangular corrugated portion is 30 ° to 60 °. It will be -30 ° to -60 °.

According to the power transmission shaft of the present invention, the diameter (outer diameter dimension) of the hollow fiber reinforced plastic shaft main body can be increased, and the fiber orientation angle of the fiber reinforced plastic of the shaft main body can be set to a torque load. By configuring so as to be in the same direction as the stress generated on the hypotenuse of each triangular portion in the state, the torsional strength of the fiber reinforced plastic can be secured at a high level. Further, when the fiber orientation angle is 30 ° to 60 ° (-30 ° to -60 °), the angle formed with respect to the shaft main axis of the hypotenuse of each triangular portion of the triangular waveform portion is 30 ° to 60 °. By setting the angle to -30 ° to -60 °, the triangular portion has a triangular shape with a vertex portion of about 60 ° to 120 °, and the strength depending on the shape is also stabilized. That is, if the apex portion has an acute angle of about 60 ° or less, the so-called tapered shape results in unstable strength due to the shape, and conversely if the obtuse angle is 120 °, the axial length of the fitting portion is shortened. This makes it difficult to achieve a stable torque transmission function.

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

A ring-shaped collar member is externally fitted to the meshing portion where the triangular corrugated portion meshes, a sheet material formed by impregnating a fiber with a resin is wound, or a fiber body formed by impregnating a resin is wound. be able to. By these, it can prevent that the meshing part which a triangular waveform part meshes expands to an outer diameter side (diameter expansion) at the time of 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 on which the triangular wave portion is formed may be an integrally molded product 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, it is possible to provide a power transmission shaft that can be reduced in weight and can effectively exhibit the torque transmission function.

¡In the case where the core metal is fitted into the shaft body, the shaft body can be prevented from buckling and contribute to the improvement of torsional strength. If it is covered with a protective pipe material, this protective pipe material can serve as a core metal for torsional strength reinforcement on the outer peripheral side of the shaft body, and foreign matter (for example, stepping stones) ) And ultraviolet rays.

By externally fitting a collar member or the like to the meshing portion where the triangular wave portion meshes, it can be prevented from expanding (expanding) to the outer diameter side when torque is applied, and can be prevented from degrading the bonding force and stable over a long period of time. Torque transmission function can be exhibited.

∙ By impregnating a large number of short fibers, the strength of the fiber reinforced plastic can be improved, and a power transmission shaft with higher durability can be provided.

Also, if the short shaft part is an integrally molded product with the outer joint member, the connection work of the short shaft part 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 with 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 coat | covered the collar member in the meshing part which a triangular waveform part meshes | engages. It is an enlarged view of the state which wound the sheet | seat which impregnated resin to the fiber whose fiber orientation angle | corner becomes 45 degrees around the meshing part. It is a top view of the power transmission shaft which wound around the meshing part the sheet | seat which impregnated resin to the fiber whose fiber orientation angle | corner is 90 degrees. It is sectional drawing of the power transmission shaft which shows other embodiment.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. This power transmission shaft is used for, for example, automobiles and various industrial machines, and is used for a drive shaft and the like.

This 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 Barfield type constant velocity universal joint is used for the fixed type constant velocity universal joint 31, and a tripod type constant velocity universal joint is used for the sliding type constant velocity universal joint 32.

The fixed type constant velocity universal joint 31 includes an outer joint member 35 in which a plurality of track grooves 33 extending in the axial direction are formed on the inner diameter surface 34, and a plurality of track grooves 36 extending in the axial direction on the outer diameter surface 37 in the circumferential direction. An inner joint member 38 formed at equal intervals, a plurality of balls 39 interposed between the track groove 33 of the outer joint member 35 and the track groove 36 of the inner joint member 38 to transmit torque, and the outer joint member A cage 40 interposed 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 includes an outer joint member 52 provided with three track grooves 51 extending in the axial direction on the inner periphery and provided with roller guide surfaces 51a facing each other on the inner wall of each track groove 51; A tripod member 54 having three leg shafts 53 projecting in the radial direction, an inner roller 55 fitted on the leg shaft 53, and an outer roller inserted into the track groove 51 and fitted on the inner roller 55 56. That is, the sliding type 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 is movable along the roller guide surface 51a. The tripod member 54 includes a boss 57 and the leg shaft 53. The leg shaft 53 protrudes in the radial direction from the circumferentially divided position of the boss 57.

The shaft end fitting portion of the shaft 61 is fitted 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 into the shaft 62. The ends of both shaft end fitting portions of the

shafts

61 and 62 are prevented from coming off by retaining

rings

65 and 65 such as snap rings. That is,

circumferential grooves

66 and 66 are formed at the end of the shaft end fitting portion, and the retaining rings 65 and 65 are fitted into the

circumferential grooves

66 and 66.

Male splines

67 and 67 are formed on the outer diameters of the shaft end fitting portions of the

shafts

61 and 62, and

female splines

68 and 68 are formed in the shaft holes of the inner joint member 38 and the tripod member 54 of both constant velocity universal joints. Is formed. The male splines 67 and 67 and the

female splines

68 and 68 are engaged by fitting the shaft end fitting portions of the

shafts

61 and 62 into the inner joint members 38 of the constant velocity

universal joints

31 and 32 and the shaft holes of the tripod member 54. By combining them, the torque can be transmitted between the shaft 61 and the inner joint member 38, and the torque can be transmitted between the shaft 62 and the tripod member 54.

Between the

shafts

61 and 62 and the outer

joint members

35 and 52,

boots

30A and 30B for preventing entry of foreign matter from the outside and leakage of grease from the inside are mounted, respectively. The

boots

30A and 30B include a large-diameter end portion 30a, a small-diameter end portion 30b, and a bellows portion 30c that connects the large-diameter end portion 30a and the small-diameter end portion 30b. The large-diameter end 30a of the boot 30 is fastened and fixed by

boot bands

45A and 45B at the open ends of the outer

joint members

35 and 52, and the small-diameter end 30b is fastened and fixed by

boot bands

46A and 46B at predetermined portions of the shaft. Yes.

The power transmission shaft 1 includes metal

short shaft portions

2A and 2B connected to the cup bottom portions 35a and 52b of the outer

joint members

35 and 52 of the constant velocity

universal joints

31 and 32, and the

short shaft portions

2A and 2B. A shaft main body 3 made of hollow fiber reinforced plastic is provided between them. The fiber reinforced plastic of the shaft body 3 has directional fibers.

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

The shaft body 3 is formed by, for example, a filament wanding method. Here, the filament wanding method is a method in which a reinforcing fiber impregnated with a resin 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 a creel.

Therefore, in the shaft body 3, as shown in FIG. 1, the fiber reinforced plastic has directional fibers, and the fiber orientation angle θ is + 45 °. And a second fiber winding portion M2 having a fiber orientation angle θ of −45 °.

Further, as shown in FIG. 2, a triangular corrugated portion 11 in which a plurality of triangular portions 10 are arranged along the circumferential direction is formed at the end of the shaft body 3. In this case, the triangular portion 10 forms an isosceles triangle having an angle α of 45 ° with respect to the shaft axis in the plan view. Note that the top of the triangular portion 10 is rounded.

In this case, as shown in FIG. 1, the outer diameter D1 of the

short shaft portions

2A and 2B and the outer diameter D2 of the shaft body 3 are set to be the same as the thickness T1 of the

short shaft portions

2A and 2B. The wall 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 fitted into the shaft body 3. As the core metal 15, for example, steel for mechanical structure represented by S53C or S43C, 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 thermosetting treatment to ensure the strength, but if the outer diameter dimension can be set relatively large and the strength can be ensured, the thermosetting treatment is not performed. There may be. When cured, the surface hardness is 52 HRC to 65 HRC. The wall thickness of the metal core 15 is set to be smaller than the wall thickness T2 of the shaft body 3 in the figure, but can be changed variously depending on the material used. 3 may be the same as the wall thickness dimension T 2, or the core bar 15 may be thicker than the wall thickness dimension T 2 of the shaft body 3.

The

bottom wall portions

35a and 52a of the outer

joint members

35 and 52 of the constant velocity

universal joints

31 and 32 are provided with bulging

portions

41 and 41, respectively. The parts are respectively fitted externally, and the cored bar 15 is integrated with the bulging

parts

41 and 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, it joins in the state in which the end surface 6 of the metal core 15 was faced | matched by the end surfaces 42 and 42 of the large diameter part 41a of the bulging part 41. In addition, the end surfaces 7 of the

short shaft portions

2A and 2B are joined to the

bottom wall portions

35a and 52a by joining means such as welding in a state where the end surfaces 7 are also abutted against the end surfaces 42 and 42.

As shown in FIG. 2, the triangular portion 8 of the short shaft portions 2 A and 2 B and the triangular portion 10 of the shaft body 3 have the same shape and are arranged at the same pitch along the circumferential direction. . For this reason, the triangular portion 10 of the shaft main body 3 is fitted into the triangular concave portion 12 formed between the triangular portions 8 adjacent to each other in the circumferential direction of the

short shaft portions

2A and 2B, and the shaft main body 3 The triangular portions 8 of the

short shaft portions

2A and 2B are fitted into triangular concave portions 13 formed between adjacent triangular portions 10 in the circumferential direction. That is, the triangular waveform portion 9 of the

short shaft portions

2A and 2B meshes with the triangular waveform portion 11 of the shaft body 3.

In this case, the angles α and β of the hypotenuse 10a of the triangular portion 10 of the shaft body 3 and the hypotenuse 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 main body 3 is 45 °. The fiber orientation angle θ of the fiber (wound in the A direction) is + 45 °, and the fiber orientation angle θ of the second fiber (the fiber is wound in the B direction) is −45 °. The direction of stress generated during torque load and the direction of fiber are the same.

By the way, the fiber orientation angle θ of the first fiber (A-direction fiber) of the shaft body 3 is not limited to + 45 °, and may be + 30 ° to + 60 °. The fiber of the second fiber (B-direction fiber) The orientation angle θ may be −30 ° to −60 °. Therefore, the angle β of the hypotenuse of the triangular portion 10 of the shaft body 3 and the hypotenuse of the triangular portion 8 of the

short shaft portions

2A and 2B is not limited to 45 °, and may be 30 ° to 60 °. . That is, it suffices if the direction of the stress generated during torque loading and the direction of the fiber can be set in the same direction.

Further, the resin of the shaft body 3 can be a thermoplastic resin such as PA (nylon), PP (polypropylene), PEEK (polyetherketone) or the like, even if it is a thermosetting resin such as an epoxy resin. .

As the fiber reinforced plastic, when the fibers are impregnated through the resin layer in advance, innumerable short fibers are impregnated while being stirred in the resin layer, and the fibers to be wound (the first fiber winding portion M1 and the second fiber winding). The short fiber may be attached to the fiber winding part M2). Thereby, in addition to the long fibers wound in the cured resin, innumerable short fibers are contained. The fiber length of the short fiber is less than 1 mm.

Next, in FIG. 3, a collar member 16 made of a short cylinder is externally fitted to a meshing portion S between the triangular corrugated portion 9 of the short shaft portion 2 A and the triangular corrugated portion 11 of the shaft body 3. As the collar member 16, for example, mechanical structural steel represented by S53C, S43C, or the like, or 10B38 in which quenching depth and strength are improved by adding boron can be used. Further, it may be alloy steel such as stainless steel or non-ferrous metal such as aluminum alloy or resin for the purpose of weight reduction. Although not shown, the collar member 16 may be externally fitted to the short shaft portion 2B as well.

The collar member 16 is press-fitted into the meshing portion S between the triangular corrugated portion 9 of the

short shaft portions

2A and 2B and the triangular corrugated portion 11 of the shaft body 3, thereby covering the meshing portion S. In addition, since the collar member 16 is not a member for transmitting torque, even if the collar member 16 is made of metal, it is not necessary to perform the thermosetting process. It may be a thing. In the case of heat curing, the surface hardness is 52 HRC to 65 HRC. The thickness 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 corrugated portion 9 of the short shaft portion 2 A and the triangular corrugated portion 11 of the shaft body 3. . In this case, similar to the fibers of the shaft body 3, the fibers are provided with A-direction fibers having a fiber orientation angle θ of + 45 ° and B-direction fibers having a fiber orientation angle θ of −45 °. In FIG. 5, the fiber orientation direction of the sheet material 17 is the circumferential direction. Moreover, it may replace with the sheet | seat material 17 which impregnated resin, and what wound the fiber body formed by impregnating resin may be wound. 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 coating the outer periphery of the shaft body 3 with a protective pipe material 20.

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. Then, the triangular portion 10 of the shaft main body 3 is fitted into the triangular concave portion 12 formed between the triangular portions 8 adjacent to each other in the circumferential direction of the

short shaft portions

2A and 2B, and the circumference of the shaft main body 3 is The triangular portions 8 of the

short shaft portions

2A and 2B are fitted into the triangular concave portions 13 formed between the triangular portions 10 adjacent to each other in the direction. That is, the triangular waveform portion 9 of the

short shaft portions

2A and 2B meshes with the triangular waveform portion 11 of the shaft body 3 (see FIG. 2).

The protective pipe material 20 is externally fitted to the

short shaft portions

2A and 2B and the shaft body 3. As the protective pipe material 20, for example, steel for machine structure typified by S53C or S43C, 10B38 or the like which is improved in quenching depth and strength by adding boron is used, as in the case of the core metal 15. Can do. In this case as well, it is preferable to secure the strength by performing a thermosetting treatment, but if the outer diameter dimension can be set relatively large and the strength can be secured, the thermosetting treatment is not performed. There may be. When cured, the surface hardness is 52 HRC to 65 HRC.

With both

end portions

20a, 20a of the protective pipe member 20 being externally fitted to the

short shaft portions

2A, 2B, the end surfaces thereof are butted against the end surfaces 43 of the

bottom wall portions

35a, 52a of the outer

joint members

35, 52. Then, 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 member 20 is also set. The outer diameter D2 of the shaft body 3 is set to be the same. Also in this case, the outer diameter D2 of the shaft 3 and the outer diameter D1 of the

short shaft portions

2A and 2B are set to the same size, and the thickness T2 of the shaft 3 and the

short shaft portions

2A and 2B The wall 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 meshes with the triangular waveform portion 11 of the shaft body 3. In this state, the protective pipe member 20 is fitted on the shaft body 3.

In the power transmission shaft of the present invention, the diameter (outer diameter) of the shaft body 3 made of hollow fiber reinforced plastic can be increased, and the fiber orientation angle of the fiber reinforced plastic of the shaft body 3 can be set to a torque load. By configuring so as to be in the same direction as the stress direction generated on the hypotenuse of each

triangular portion

8, 10 in the state, the torsional strength of the fiber reinforced plastic can be secured at a high level. Further, by setting the angle formed with respect to the shaft main axis of the hypotenuse of the

triangular portions

8 and 10 of the

triangular waveform portions

9 and 11 to 30 ° to 60 °, the triangular portion 10 has a vertex portion. It forms a triangular shape of about 60 ° to 120 °, and the strength due to the shape is also stable. That is, if the apex portion has an acute angle of about 60 ° or less, the so-called tapered shape is obtained and the strength due to the shape is not stable, and conversely if the obtuse angle is 120 °, the axial length of the meshing portion S is shortened. This makes it difficult to achieve a stable torque transmission function.

Therefore, 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, it is possible to provide a power transmission shaft that can be reduced in weight and can effectively exhibit the torque transmission function. In particular, the angle formed with respect to the shaft main axis of the

hypotenuses

8a and 10a of the

triangular portions

8 and 10 of the

triangular wave portions

9 and 11 is set to 45 °, and the fiber orientation angle of the fiber reinforced plastic of the shaft main body 3 is set. By setting the angle to ± 45 °, there is an advantage that it can be easily set in the same direction as the stress direction generated on the

hypotenuses

8a and 10a of the

triangular portions

8 and 11 in the torque load state.

When the core 15 is fitted into the shaft body 3, the shaft body 3 can be prevented from buckling and contribute to improving 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, it is possible to prevent the outer diameter side from being expanded (expanded) at the time of torque load, thereby reducing the bonding force. The torque transmission function can be exhibited stably over a long period of time.

When impregnated with a large number of short fibers, the strength of the fiber reinforced plastic can be improved, and a power transmission shaft with higher durability can be provided.

As long as it is covered with the protective pipe material 20, the protective pipe material 20 can serve as a core metal for torsional strength reinforcement on the outer peripheral side of the shaft body 3, and foreign matter from the outside. (For example, stepping stones) and ultraviolet rays can be protected.

As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. In the power transmission shaft, buckling can be avoided and torsional strength is ensured. If it is possible to obtain the shaft main body 3 capable of performing the above, the core metal 15, the protective pipe member 20, and the like may be omitted. Further, the fiber reinforced plastic of the shaft body 3 may not be impregnated with short fibers.

Further, the number and size of the triangular portion 10 of the shaft main body 3 can be arbitrarily set according to the diameter dimension, the thickness dimension, etc. of the shaft main body 3. In addition, in the said embodiment, although rounded by forming a rounded part as a top part of each triangular-shaped part 10, you may not give such roundness.

When joining the metal core 15 or the protective pipe material 20, it may be performed by friction welding (friction welding / pressure welding) in addition to welding. Friction welding is a bonding method in which a metal material is caused to make a relative motion while being contact-pressed 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.

In the above embodiment, the filament winding method is shown as a method for producing the shaft body 3 made of fiber reinforced plastic, but other methods such as a sheet winding method may be adopted. Here, the sheet winding method means that a sheet-like fiber is impregnated with resin on the outside of a rotating mandrel, and a semi-cured state (prepreg) is wound and cured, and then the mandrel is pulled out to form a pipe-like shape. It is a method of molding a thing.

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

This power transmission shaft can be a power transmission shaft used in automobiles and various industrial machines. Even if the fixed constant velocity universal joint is a Barfield type or an undercut-free type constant velocity universal joint, the sliding type constant velocity universal joint is a tripod type, double offset type, or cross groove type constant velocity universal joint. A joint may be used. You may use for propeller shafts other than a drive shaft. Further, when the tripod type is used as the sliding type constant velocity universal joint, it may be a single roller type or a double roller type.

S meshing part

2A, 2B short shaft part 3

shaft body

8, 10

triangular part

9, 11 triangular corrugated part 15 core metal 16 color member 17 sheet material 20 protective pipe material 31 fixed type constant velocity universal joint 32 sliding type etc. Fast universal joint

Claims

A power transmission shaft for connecting a pair of constant velocity universal joints,
A metal short shaft portion connected to the cup bottom portion of the outer joint member of each constant velocity universal joint, and a hollow fiber reinforced plastic shaft main body disposed between the short shaft portions, the fiber of the shaft main body Reinforced plastic has directional fibers, and at the end of each short shaft part, a triangular corrugated part is formed by arranging a plurality of triangular parts along the circumferential direction, and both ends of the shaft body Forming a triangular corrugated portion in which a plurality of triangular portions are arranged along the circumferential direction, and the side of the triangular corrugated portion on the short axis side and the side of the triangular corrugated portion on the shaft body side are formed The short shaft portion and the shaft main body are linearly arranged and integrated in a state where the shaft main body is interposed between the pair of short shaft portions by contact meshing, and the fiber orientation angle of the fiber reinforced plastic of the shaft main body On the hypotenuse of each triangular part under torque load condition. Power transmission shaft, characterized by being configured such that the stress in the same direction that.
2. The power transmission shaft according to claim 1, wherein a cored bar is fitted into the shaft main body.
3. The power transmission shaft according to claim 1, wherein a ring-shaped collar member is externally fitted to a meshing portion where the triangular wave portion meshes.
The power transmission shaft according to claim 1 or 2, wherein a sheet material in which a fiber is impregnated with resin is wound around a meshing portion where the triangular corrugated portion meshes.
3. The power transmission shaft according to claim 1 or 2, wherein a fiber body impregnated with resin is wound around a meshing portion where the triangular corrugated portion meshes.
The power transmission shaft according to any one of claims 1 to 5, wherein the fiber reinforced plastic of the shaft 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 on which the triangular wave portion is formed is a product integrally formed with the outer joint member of the constant velocity universal joint.
2. The power transmission shaft according to claim 1, wherein the hollow fiber reinforced plastic shaft main body and the meshing portion with which the triangular corrugated portion meshes are covered with a protective pipe material.