JP2019167989A - Constant velocity universal joint shaft - Google Patents

Abstract

To improve torsional strength of a shaft that includes a metal part and a fiber-reinforced plastic part.SOLUTION: A shaft 1 includes: a metal shaft body 2; and a fiber-reinforced plastic shaft sub-body 3. The shaft 1 includes a friction stir welding part 4 in which the shaft body 2 and the shaft sub-body 3 are joined.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a shaft for connecting constant velocity universal joints used in automobiles and industrial machines.

  Conventionally, a metal (steel) solid shaft has been widely used as a shaft for connecting a constant velocity universal joint on the outboard side and a constant velocity universal joint on the inboard side in a drive system such as an automobile.

  However, in recent years, with increasing demand for improved fuel economy and quietness of vehicles, it has become a challenge to make the shaft more rigid than before in terms of weight reduction and vibration reduction. As a means for solving this problem, for example, Patent Document 1 discloses a shaft that is reduced in weight and improved in vibration characteristics by being hollowed out. However, in order to ensure high strength of the shaft, the shaft still needs to be made of metal (steel), and a sufficient weight reduction effect could not be obtained.

  Patent Document 2 discloses a power transmission shaft including a steel shaft main body and a fiber reinforced plastic shaft subbody as a technique for achieving both weight reduction and high rigidity. In this power transmission shaft, the shaft main body and the shaft sub-body are provided with a triangular corrugated portion in which a plurality of triangular portions are disposed along the circumferential direction at the ends thereof. The shaft main body and the shaft sub-body are integrated linearly by engaging the triangular corrugated portion on the shaft main body side with the triangular corrugated portion on the shaft sub-body side in a state where the respective end portions are abutted.

  In this power transmission shaft, in order to ensure a high level of torsional strength, the fiber orientation angle of the fiber reinforced plastic of the shaft sub-body is set in the same direction as the stress direction generated on the hypotenuse of each triangular portion in the torque load state. It is composed.

JP-A-5-263819 JP-A-2006-95010

  However, in the state where the triangular corrugated portion of the shaft main body and the triangular corrugated portion of the shaft sub body are meshed as in the power transmission shaft according to Patent Document 2, the shaft main body and the shaft sub body remain separate members. They are joined only by physical contact between the triangular waveform portions. For this reason, the torsional strength of the power transmission shaft is affected by the strength (rigidity) of the triangular corrugated portion. In particular, when a steel shaft body and a fiber reinforced plastic shaft subbody are joined, the torsional strength is greatly affected by the strength of the matrix material related to the fiber reinforced plastic. For this reason, it is difficult to further increase the torsional strength of the power transmission shaft in the joining mode in which only the shaft main body and the shaft subbody are in contact with each other.

  This invention is made | formed in view of said situation, and makes it a technical subject to raise the torsional strength of the shaft which has a metal part and a fiber reinforced plastic part.

  The present invention is for solving the above-mentioned problem, and in a constant velocity universal joint shaft comprising a metal shaft main body and a fiber reinforced plastic shaft subbody, the shaft main body and the shaft subbody It comprises a friction stir welding part which joins.

  The friction stir welding part according to the present invention is configured by friction stir welding a shaft main body and a shaft sub body. In friction stir welding, a tool is pressed against a part to be joined of two members, the part to be joined is softened by frictional heat due to rotation of the tool, and the softened part is stirred and mixed by rotation of the tool. It is the method of joining. That is, the friction stir weld is configured by mixing (compositing) the metal of the shaft body and the fiber reinforced plastic of the shaft sub-body. For this reason, in this invention, compared with the case where a shaft main body and a shaft subbody are joined only by physical contact like before, a shaft main body and a shaft subbody can be joined more firmly. Thus, by increasing the joint strength of the joint portion (friction stir joint) between the shaft main body and the shaft sub-body, the torsional strength of the constant velocity universal joint shaft can be greatly improved.

  In the constant velocity universal joint shaft having the above-described configuration, the shaft sub body includes a first fiber having a fiber orientation angle of + 45 ° with respect to an axial direction of the shaft sub body and a second fiber having a fiber orientation angle of −45 °. It is desirable to be configured by overlapping. Thereby, the torsional strength of the shaft sub-body can be increased. Therefore, the torsional strength of the constant velocity universal joint shaft can be further increased by joining the shaft sub-body to the shaft body by the friction stir joint.

  Not only said structure but the said shaft sub-body is comprised by the 1st fiber and 2nd fiber which differ in the fiber orientation angle with respect to the axial center direction of the said shaft sub-body in the range of 0 degree-45 degrees overlapping. Also good.

  In the constant velocity universal joint shaft having the above-described configuration, it is desirable that the outer diameter of the shaft body and the outer diameter of the shaft sub-body are equal. In the present invention, since the shaft main body and the shaft sub body are joined by the friction stir joint, it is not necessary to increase the outer diameter of the shaft main body or the shaft sub body for joining. Thereby, the constant velocity universal joint shaft can be miniaturized as much as possible, and further weight reduction can be realized.

  In the constant velocity universal joint shaft having the above-described configuration, it is preferable that a protective layer including a fiber having a fiber orientation angle of 90 ° with respect to an axial direction of the shaft sub-body is provided on the outer surface of the friction stir joint. As described above, since the protective layer has fibers with a fiber orientation angle of 90 °, it is possible to effectively prevent the deformation of the friction stir welded portion in the radial direction, and to realize a highly reliable shaft.

  According to the present invention, the torsional strength of a shaft having a metal portion and a fiber reinforced plastic portion can be increased.

It is a perspective view of the constant velocity universal joint shaft according to the first embodiment. It is sectional drawing of the shaft for constant velocity universal joints. It is sectional drawing of the drive shaft containing the shaft for constant velocity universal joints. It is sectional drawing which shows the method of joining a shaft main body and a shaft subbody. It is a perspective view which shows the method of joining a shaft main body and a shaft subbody. It is sectional drawing of the shaft for constant velocity universal joints concerning 2nd embodiment. It is sectional drawing which shows the method of joining a shaft main body and a shaft subbody. It is sectional drawing of the shaft for constant velocity universal joints concerning 3rd embodiment. It is sectional drawing which shows the method of joining a shaft main body and a shaft subbody. It is sectional drawing of the shaft for constant velocity universal joints which concern on 4th embodiment. It is sectional drawing of the shaft for constant velocity universal joints which concern on 5th embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. 1 to 5 show a first embodiment of a constant velocity universal joint shaft (hereinafter simply referred to as “shaft”) according to the present invention.

  The shaft 1 is used, for example, in a drive system for automobiles and various industrial machines. As shown in FIGS. 1 to 3, the shaft 1 is connected to a pair of metal shaft bodies 2 and the shaft body 2. And a friction stir welding portion 4 for joining the shaft main body 2 and the shaft secondary body 3 to each other.

  FIG. 3 shows a drive shaft using the shaft 1 according to the present embodiment. This drive shaft is configured by connecting a fixed type constant velocity universal joint 5 and a sliding type constant velocity universal joint 6 with a shaft 1. In the present embodiment, the fixed constant velocity universal joint 5 is exemplified by a Barfield type constant velocity universal joint, and the sliding constant velocity universal joint 6 is exemplified by a tripod type constant velocity universal joint.

  The fixed type constant velocity universal joint 5 includes an outer joint member 9 having a plurality of track grooves 7 formed on the inner diameter surface 8, an inner joint member 12 having a plurality of track grooves 10 formed on the outer diameter surface 11, and an outer joint. A plurality of balls 13 interposed between the track groove 7 of the member 9 and the track groove 10 of the inner joint member 12 to transmit torque, the inner diameter surface 8 of the outer joint member 9 and the outer diameter surface 11 of the inner joint member 12. And a cage 14 that holds the ball 13 interposed therebetween.

  The sliding type constant velocity universal joint 6 is provided with an outer joint member 16 provided with three track grooves 15 on the inner periphery and roller guide surfaces 15a facing each other on the inner wall of each track groove 15, and a radius from the boss 17. A tripod member 19 having three leg shafts 18 projecting in the direction, an inner roller 20 that is externally fitted to the leg shaft 18, and an outer roller 21 that is inserted into the track groove 15 and that is externally fitted to the inner roller 20 are provided. That is, the sliding type constant velocity universal joint 6 is a double roller type in which the outer roller 21 is rotatable with respect to the leg shaft 18 and is movable along the roller guide surface 15a.

  A male spline 22 is formed at the end of the shaft 1. A female spline 23 is formed in the shaft hole of the inner joint member 12 and the tripod member 19 of each constant velocity universal joint 5, 6. The end of the shaft 1 is fitted into the shaft hole of the inner joint member 12 and the tripod member 19 of the constant velocity universal joints 5 and 6. As a result, the male spline 22 and the female spline 23 mesh with each other, and torque transmission between the shaft 1, the inner joint member 12, and the tripod member 19 becomes possible. Each end portion of the shaft 1 is provided with a circumferential groove 24. The shaft 1 is prevented from coming off by a retaining ring 25 fitted in the circumferential groove 24.

  Between the shaft 1 and each of the outer joint members 9 and 16, boots 26 for preventing entry of foreign matter from the outside and leakage of grease from the inside are respectively mounted. The boot 26 includes a large-diameter end portion 26a, a small-diameter end portion 26b, and a bellows portion 26c that connects the large-diameter end portion 26a and the small-diameter end portion 26b. The large-diameter end portion 26 a of the boot 26 is fastened and fixed by the boot band 27 at the open ends of the outer joint members 9 and 16. The small-diameter end portion 26 b of the boot 26 is fastened and fixed by a boot band 28 at a predetermined portion of the shaft 1.

  As shown in FIGS. 1 to 3, the shaft body 2 includes a stub shaft 30 provided with a large-diameter portion 29 at one end and the male spline 22 at the other end. .

  The stub shaft 30 is made of, for example, steel for machine structure represented by S53C, S43C, or the like, or a steel material for which the quenching depth and strength are improved by adding boron. In the stub shaft 30, it is desirable to subject the portion including the male spline 22 to thermosetting treatment such as high-frequency heat treatment or carburizing heat treatment.

  The shaft sub-body 3 is formed in a cylindrical shape from fiber-reinforced plastic. 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 a 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. As the matrix material of the fiber reinforced plastic, a thermosetting resin such as an epoxy resin or a thermoplastic resin such as PA (nylon), PP (polypropylene), or PEEK (polyether ketone) is used.

  As shown in FIG. 2, the outer diameter dimension D2 of the shaft sub-body 3 configured in a cylindrical shape is equal to the outer diameter dimension D1 of the large diameter portion 29 of the shaft body 2 (D1 = D2).

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

  As shown in FIG. 2, the shaft sub-body 3 includes fibers M1 and M2 that overlap at a predetermined fiber orientation angle θ1 and θ2 with respect to the axial direction (direction along the axis X). That is, the shaft sub-body 3 includes a first fiber M1 having a fiber orientation angle θ1 of + 45 ° and a second fiber M2 having a fiber orientation angle θ2 of −45 °. The fiber orientation angle θ1 of the first fiber M1 is not limited to + 45 °, and may be + 30 ° to + 60 °. Similarly, the fiber orientation angle θ2 of the second fiber M2 is not limited to −45 °, and is −30. It suffices if it is between deg.

  The friction stir welding portion 4 is configured by friction stir welding a part of the shaft body 2 and a part of the shaft sub body 3. In friction stir welding, a tool is pressed against a joining target part of two members to be processed, the joining target part is softened by frictional heat generated by the rotation of the tool, and the softened part is stirred and mixed by the rotation of the tool. This is a method of joining two members.

  Hereinafter, a method of integrating the shaft main body 2 and the shaft sub-body 3 by friction stir welding (manufacturing method of the shaft 1) will be described in detail with reference to FIGS.

  First, as shown in FIG. 4, the end surface 29 a of the large-diameter portion 29 related to the shaft body 2 and the end surface 3 a of the shaft sub-body 3 are brought into contact (matched). Thereafter, the rotary tool 33 is brought into contact with the contact portion 32 between the end surface 29a of the large diameter portion 29 and the end surface 3a of the shaft sub body 3 from the outside. The rotary tool 33 includes a probe unit 34 and a shoulder unit 35 that supports the probe unit 34. The probe portion 34 is disposed so as to be orthogonal to the axis X of the shaft body 2 and the shaft sub body 3. The shoulder portion 35 is configured to have a larger diameter than the probe portion 34. The shoulder portion 35 rotates together with the probe portion 34 while pressing the contact portion 32 from the outside.

  In this method, the rotary tool 33 is rotated, and the probe portion 34 is interposed in the contact portion 32 between the end surface 29 a of the large diameter portion 29 and the end surface 3 a of the shaft sub body 3. The contact portion 32 is heated by friction with the rotating probe portion 34. By this heating, a part of the large diameter portion 29 and a part of the shaft sub-body 3 existing in the contact portion 32 and the periphery thereof are softened. The probe part 34 and the shoulder part 35 agitate the softened part by the rotation, and plastically flow the softened part. By this stirring, the softened portion (steel) of the shaft body 2 and the softened portion (fiber reinforced plastic) of the shaft subbody 3 are mixed.

  As shown in FIG. 5, in this method, the rotary tool 33 is rotated, and the shaft body 2 and the shaft subbody 3 are rotated about the axis X (the direction of rotation is indicated by an arrow R). Thereby, friction stir welding is performed over the entire circumference of the contact portion 32. When the softened portion mixed by the agitation is solidified, the friction stir welding portion 4 formed by combining and integrating a part of the shaft body 2 and a part of the shaft subbody 3 is formed over the entire circumference of the shaft 1. It is formed.

  According to the shaft 1 according to the present embodiment described above, the shaft main body 2 and the shaft subbody 3 are combined and integrated by the friction stir welding portion 4 in a conventional manner. Compared with the case where the shaft sub-body 3 is joined only by physical contact, it is possible to increase the joint strength of the joint (friction stir joint 4). Thereby, the rigidity (torsional strength) of the shaft 1 can be significantly improved.

  6 and 7 show a second embodiment of the shaft according to the present invention. In the shaft 1 according to the present embodiment, the shaft body 2 includes a protrusion 36 that is joined to the outer diameter surface 3 b of the shaft subbody 3. The protrusion 36 is configured in a cylindrical shape and has an inner diameter surface 36 a that can contact the outer diameter surface 3 b of the shaft subbody 3.

  In order to form the friction stir welding portion 4 on the shaft 1 in this embodiment, as shown in FIG. 7, the end portion of the shaft sub body 3 is inserted inside the cylindrical projection portion 36, and the shaft sub body 3 is inserted. The end surface 3 a is brought into contact with the end surface 29 a of the large diameter portion 29. At this time, the outer diameter surface 3 b of the shaft sub-body 3 is overlapped with the inner diameter surface 36 a of the protrusion 36. In the present embodiment, friction stir welding is performed on at least a part of the abutting portion 32 of the overlapped outer diameter surface 3b and inner diameter surface 36a, whereby the large-diameter portion 29 (projection portion 36) and the shaft sub-body. 3 is formed (see FIG. 6).

  In this embodiment, since the shaft sub body 3 is inserted inside the protrusion 36, the outer diameter D1 of the large diameter portion 29 (protrusion 36) is the outer diameter of the shaft sub body 3. It becomes larger than D2 (D1> D2).

  8 and 9 show a third embodiment of the shaft according to the present invention. In the shaft 1 according to the present embodiment, the shaft body 2 has a small diameter portion 37 at the end of the large diameter portion 29. The small diameter portion 37 is configured in a columnar shape, but is not limited thereto and may be configured in a cylindrical shape. The small diameter portion 37 has an end surface 37 a and an outer diameter surface 37 b having a smaller diameter than the outer diameter surface 29 b of the large diameter portion 29.

  In order to form the friction stir welding portion 4 on the shaft 1 in the present embodiment, the small diameter portion 37 of the shaft body 2 is inserted into the shaft sub body 3 as shown in FIG. Is brought into contact with (contacted with) the end surface 29 a of the large-diameter portion 29. At this time, the outer diameter surface 3 b of the shaft sub-body 3 is flush with the outer diameter surface 29 b of the large diameter portion 29 of the shaft body 2. A part of the inner diameter surface 3 c of the shaft sub-body 3 is in contact with the outer diameter surface 37 b of the small diameter portion 37.

  Thereafter, friction stir welding is performed on a contact portion 32 between the end surface 29 a of the large-diameter portion 29 of the shaft body 2 and the end surface 3 a of the shaft sub body 3. By this friction stir welding, the contact portion 32 (interface) disappears, and a friction stir welding portion 4 that integrally joins the shaft body 2 and the shaft sub-body 3 is formed (see FIG. 8).

  In the present embodiment, the outer diameter surface 37 b of the small diameter portion 37 is formed so that the softened portion is inward in the radial direction of the shaft 1 when the contact portion 32 between the shaft body 2 and the shaft subbody 3 is softened by frictional heat. It functions as a flow restricting part that prevents plastic flow. Thereby, the further weight reduction of the shaft 1 is attained.

  Further, according to the present embodiment, the shaft sub-body 3 is formed on the step formed by the large diameter portion 29 and the small diameter portion 37 of the shaft body 2 (the end surface 29a of the large diameter portion 29 and the outer diameter surface 37b of the small diameter portion 37). Can be positioned with high accuracy with respect to the shaft main body 2. Thereby, the friction stir welding part 4 can be shape | molded with sufficient precision, the shaft 1 which is reduced in weight and has high rigidity and high dimensional accuracy can be manufactured.

  FIG. 10 shows a fourth embodiment of the shaft according to the present invention. In the shaft 1 according to the present embodiment, the orientation mode of the fibers M1 and M2 in the shaft subbody 3 is different from that in the first embodiment. That is, in this shaft sub-body 3, the fiber orientation angle θ1 of the first fiber M1 and the fiber orientation angle θ2 of the second fiber M2 are different in the fiber orientation angle range of 0 ° to 45 °. In the present embodiment, for example, the fiber orientation angle θ1 of the first fiber M1 is + 45 °, and the fiber orientation angle θ2 of the second fiber M2 is + 30 °. For example, when the fiber orientation angle θ1 of the first fiber M1 is + 45 °, the fiber orientation angle θ2 of the second fiber M2 is preferably set in the range of + 5 ° to + 30 °.

  FIG. 11 shows a fifth embodiment of the shaft according to the present invention. The shaft 1 according to the present embodiment further includes a protective layer 38 provided over the entire circumference of the outer diameter surface of the friction stir welding portion 4. The protective layer 38 can be made of, for example, a sheet material in which fibers are impregnated with a resin. Alternatively, the protective layer 38 may be configured by winding a fiber body impregnated with a resin around the outer peripheral surface of the friction stir welding portion 4. The fiber M3 constituting the protective layer 38 preferably has a fiber orientation angle θ3 of 90 °. In particular, the protective layer 38 can effectively prevent deformation of the friction stir welding portion 4 in the radial direction, thereby improving the reliability of the shaft 1.

  In addition, this invention is not limited to the structure of the said embodiment, It is not limited to an above-described effect. The present invention can be variously modified without departing from the gist of the present invention.

  In the above embodiment, the filament winding method is exemplified as the method for producing the shaft sub-body 3, but the present invention is not limited to this, and other methods such as a sheet winding method may be adopted. In the sheet winding method, a sheet-like fiber is impregnated with resin on the outside of a rotating mandrel, a semi-cured state (prepreg) is wound and cured, and then the mandrel is pulled out to form a cylindrical body. Is the method.

  Not limited to the above embodiment, an undercut free type constant velocity universal joint may be used as the fixed type constant velocity universal joint 5. As the sliding type constant velocity universal joint 6, a double offset type or a cross groove type constant velocity universal joint may be used. In the above embodiment, the shaft 1 is used as a drive shaft. However, the shaft 1 may be used as a propeller shaft other than the drive shaft. When a tripod type is used as the sliding type constant velocity universal joint 6, it may be a single roller type or a double roller type.

DESCRIPTION OF SYMBOLS 1 Shaft for constant velocity universal joints 2 Shaft main body 3 Shaft subbody 4 Friction stir welding part 38 Protective layer D1 Shaft main body outer diameter D2 Shaft subbody outer diameter M1 First fiber M2 Second fiber

Claims (5)

In a constant velocity universal joint shaft comprising a shaft body made of metal and a shaft subbody made of fiber reinforced plastic,
A constant velocity universal joint shaft comprising: a friction stir welding portion for joining the shaft main body and the shaft sub body.   The shaft sub-body is configured by overlapping a first fiber having a fiber orientation angle of + 45 ° with respect to an axial direction of the shaft sub-body and a second fiber having a fiber orientation angle of -45 °. The shaft for constant velocity universal joints described in 1.   The said shaft subbody is comprised by the 1st fiber and 2nd fiber which differ in the fiber orientation angle with respect to the axial center direction of the said shaft subbody overlapping in the range of 0 degree-45 degrees etc., etc. Quick universal joint shaft.   The shaft for a constant velocity universal joint according to any one of claims 1 to 3, wherein an outer diameter of the shaft body and an outer diameter of the shaft subbody are made equal. 5. The constant velocity universal joint according to claim 1, further comprising a protective layer including a fiber having a fiber orientation angle of 90 ° with respect to an axial center direction of the shaft sub-body on an outer surface of the friction stir welding portion. Shaft.

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