JP2007315463A - Hollow power transmission shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hollow power transmission shaft for a drive shaft and a propeller shaft, having a long and lightweight structure. <P>SOLUTION: The hollow power transmission shaft is equipped with a first hollow shaft 1A and a second hollow shaft 1B including small diameter parts 11a, 11b, and large diameter parts 10a, 10b. Each of the first hollow shaft 1A and the second hollow shaft 1B are hollow over the entire length. An end face 16a of the large diameter part 10a of the first hollow shaft 1A and an end face 16b of the large diameter part 10b of the second hollow shaft 1B are integrally bonded. The large diameter parts 10a, 10b are disposed at an intermediate part in the axial direction and the small diameter parts 11a, 11b are disposed at an end in the axial direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power transmission shaft used for a drive shaft (drive shaft), a propeller shaft (propulsion shaft) and the like constituting a power transmission system of an automobile, and relates to a hollow power transmission shaft.

  As shown in FIG. 6, the power transmission mechanism of the automobile includes a power transmission shaft 101, a sliding type constant velocity universal joint 102 connected to one end of the power transmission shaft 101, and the other end of the power transmission shaft 101. And a fixed constant velocity universal joint 103 connected thereto. In this power transmission mechanism, the sliding type constant velocity universal joint 102 is connected to a reduction gear (differential), and the fixed type constant velocity universal joint 103 is connected to the drive wheel side. One end of the power transmission shaft 101 is splined to the tripod member 104 of the sliding type constant velocity universal joint 102, and a boot 106 is provided on the outer periphery of the end of the outer ring 105 of the sliding type constant velocity universal joint 102 and the outer periphery of the power transmission shaft 101. Are fixed respectively. The other end of the power transmission shaft 101 is splined to the inner ring 107 of the fixed type constant velocity universal joint 103, and a boot 109 is provided on the outer periphery of the outer ring 108 of the fixed type constant velocity universal joint 103 and the outer periphery of the power transmission shaft 101. It is fixed.

  By the way, power transmission shafts used for drive shafts and propeller shafts are roughly classified into solid shafts processed from solid bar materials and hollow shafts processed from steel pipes.

  In recent years, hollow shafts are often used due to the necessity of reducing the weight of the vehicle's undercarriage and improving its torsional rigidity and NVH characteristics. This type of hollow shaft is roughly classified into an integral hollow shaft and a joined hollow shaft. In addition, the joint-type hollow shaft includes a structure in which a pipe portion and a shaft portion are separately formed and joined by friction rolling or welding (Patent Document 1), or a pair of stub shafts formed by forging, turning, or the like. There is a structure in which end faces are joined by friction welding (Patent Document 2).

  As shown in FIG. 7, the integrated hollow shaft 101 has a structure in which a central large-diameter portion 101a having a maximum outer diameter portion and a small-diameter portion 101b provided with a spline at the end are integrally formed from the same raw tube, For example, it is formed by plastic working such as swaging or pressing.

As shown in FIG. 8, the bonded hollow shaft includes a first shaft 110 and a second shaft 111. The first shaft 110 and the second shaft 111 have solid small-diameter portions 112 and 114 and hollow large-diameter portions 113 and 115 connected to the small-diameter portions 112 and 114, respectively. In this case, the end surface of the hollow large diameter portion 113 of the first shaft 110 and the end surface of the hollow large diameter portion 115 of the second shaft 111 are joined. Further, as shown in FIG. 9, some joined hollow shafts have a first shaft 110, a second shaft 111, and an intermediate large-diameter shaft 116. In this case, an intermediate large-diameter shaft 116 is disposed between the large-diameter portion 113 of the first shaft 110 and the large-diameter portion 115 of the second shaft 111, and the end surfaces of the large-diameter portions 113 and 115 and The end surfaces of the intermediate large-diameter shaft 116 facing each other are joined and integrated.
JP-A-5-10319 JP 2001-315539 A

  Since the inside of the integral hollow shaft is hollow over the entire length of the shaft, the entire shaft is lightweight. However, with such an integrated hollow shaft, it is difficult to integrally form a long object with a hollow shaft used for a drive shaft, a propeller shaft, etc. due to equipment limitations such as processing load and processing length. . Moreover, in the joining type hollow shaft, since the parts divided into a few points are joined, it is possible to manufacture a long hollow shaft. However, in this case, the small diameter portion on the end side is solid. That is, when the hollow shaft is formed by cutting, the cost increases if the small diameter portion is made hollow by drilling. In addition, when forming by forging, it can be formed at a low cost, but it cannot be made hollow to a small diameter portion in terms of processing capability, and can only be formed to a depth that is also a large diameter portion. Thereby, conventionally, the small-diameter portion on the end side is solid. For this reason, there existed a problem that weight was heavy compared with the hollow shaft which is hollow over the full length.

  In view of the above problems, the present invention provides a hollow power transmission shaft for a drive shaft or propeller shaft that is long and lightweight.

  The hollow power transmission shaft of the present invention includes a first hollow shaft and a second hollow shaft having a small diameter portion and a large diameter portion, and the first hollow shaft and the second hollow shaft are hollow over the entire length, The end surface of the large-diameter portion of the first hollow shaft and the end surface of the large-diameter portion of the second hollow shaft are joined and integrated, and the large-diameter portion is disposed at the axial intermediate portion and the small-diameter portion is disposed at the axial end portion. It is arranged.

  In the hollow power transmission shaft of the present invention, since the hollow first hollow shaft and the second hollow shaft are joined and integrated at the end face of the large diameter portion over the entire length, the inside can be made hollow over the entire length of the shaft. Moreover, since two hollow shafts are joined, a shaft having a large overall length (axial length) can be manufactured.

  Another hollow power transmission shaft of the present invention includes a first hollow shaft and a second hollow shaft each having a small diameter portion and a large diameter portion, and the first hollow shaft and the second hollow shaft are respectively hollow over the entire length. As described above, a hollow intermediate large-diameter shaft is disposed over the entire length between the large-diameter portion of the first hollow shaft and the large-diameter portion of the second hollow portion, and the end surfaces of the large-diameter portions and the intermediate large surface facing the large-diameter portion Each end surface of the radial shaft is joined and integrated, the intermediate large-diameter shaft is disposed at the axially intermediate portion, and the small-diameter portion is disposed at the axial end portion.

  In another hollow power transmission shaft of the present invention, an intermediate large-diameter shaft that is hollow over the entire length is disposed between the large-diameter portion of the first hollow shaft that is hollow over the entire length and the large-diameter portion of the second hollow shaft. Therefore, the inside can be made hollow over the entire length of the shaft. In addition, since three hollow shafts are joined, a longer hollow shaft can be manufactured.

  The joining between the end faces can be friction welding. Thereby, each axis | shaft can be joined with high intensity | strength. The friction welding method is a kind of direct solid-phase bonding method in which solids are joined without melting them, and the members to be joined (for example, metal or resin) are rubbed together at high speed, and the members are joined by frictional heat generated at that time. It is a method of joining by applying pressure simultaneously with softening. As an advantage of this friction welding method, a product with high dimensional accuracy can be obtained by a relatively simple operation, and assembly and joining of finished members can be performed.

  Each of the shafts can be formed by plastic processing such as swaging or pressing.

  The first hollow shaft and the second hollow shaft can have the same size and shape. Thereby, the first hollow shaft and the second hollow shaft can be configured with the same one, and there is no need to manufacture two types of the first hollow shaft and the second hollow shaft. For this reason, when forming each axis | shaft by plastic processing, such as a swaging process and press work, it can process with the same tool for plastic working.

  A hardened surface layer can be formed by subjecting small diameter portions of the first hollow shaft and the second hollow shaft to induction hardening. Thereby, the intensity | strength of the small diameter part used as the weakest part can be heightened from the whole shaft.

  In the hollow power transmission shaft of the present invention, since a hollow power transmission shaft can be formed by two hollow shafts, the production of a long shaft having a hollow overall length, which has been difficult to manufacture in the past, is a new capital investment. This is possible without spending money. In addition, since the interior can be made hollow over the entire length of the shaft, if this shaft is used for a drive shaft (drive shaft), a propeller shaft (propulsion shaft) or the like that constitutes a power transmission system of an automobile, This can contribute to weight reduction, torsional rigidity and NVH characteristics.

  In other hollow power transmission shafts, an intermediate large-diameter shaft can be arranged between two hollow shafts, and a hollow power transmission shaft can be constituted by three or more hollow shafts. Can be produced. In addition, since the first hollow shaft, the intermediate large-diameter shaft, and the second hollow shaft to be joined are hollow over the entire length, the shaft is hollow over the entire length, and the weight can be reduced.

  By making the joining between the respective end faces a friction welding, a good joining can be obtained and the joining time can be shortened. For this reason, each shaft can be integrally joined with high strength, and it is advantageous for automation and mass production.

  By forming each of the shafts by plastic processing such as swaging or pressing, the material cost can be reduced compared to cutting, and the shaft can be lightened.

  There is no need to manufacture two types of the first hollow shaft and the second hollow shaft, and a plastic working tool or the like used in manufacturing the first hollow shaft and the second hollow shaft can be shared. For this reason, omission of the tool for plastic working and improvement of productivity can be aimed at, and processing cost can be reduced.

  Since the strength of the small diameter portion, which is the weakest portion in terms of strength when viewed from the entire shaft, can be increased, the entire shaft has high strength and excellent durability.

  An embodiment of a hollow power transmission shaft according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the power transmission mechanism of an automobile includes a power transmission shaft 1, a sliding type constant velocity universal joint 2 connected to one end of the power transmission shaft 1, and the other end of the power transmission shaft 1. The fixed type constant velocity universal joint 3 connected is provided.

  In this power transmission mechanism, the sliding type constant velocity universal joint 2 is connected to a reduction gear (differential), and the fixed type constant velocity universal joint 3 is connected to the drive wheel side. One end of the power transmission shaft 1 is splined to the tripod member 4 of the sliding type constant velocity universal joint 2, and a boot 6 is provided on the outer periphery of the outer ring 5 of the sliding type constant velocity universal joint 2 and the outer periphery of the power transmission shaft 1. Are fixed respectively. The other end of the power transmission shaft 1 is splined to the inner ring 7 of the fixed type constant velocity universal joint 3, and a boot 9 is provided on the outer periphery of the end of the outer ring 8 of the fixed type constant velocity universal joint 3 and the outer periphery of the power transmission shaft 1. It is fixed.

  FIG. 2 is a partial cross-sectional view of the first embodiment of the power transmission shaft 1. The shaft 1 is a hollow cylindrical member over the entire length in the axial direction, and is formed by coaxially connecting the first hollow shaft 1A and the second hollow shaft 1B. The shaft 1 has large-diameter portions 10a and 10b at an axially intermediate portion, and small-diameter portions 11a and 11b on both axial ends from the large-diameter portions 10a and 10b, respectively. 10b and the small diameter portions 11a and 11b are continuous via tapered surfaces 17a and 17b that reduce the diameter from the large diameter portions 10a and 10b toward the small diameter portions 11a and 11b. The intermediate portion in the axial direction has a connecting portion 15 for connecting the first hollow shaft 1A and the second hollow shaft 1B, and constant velocity universal joints 2 and 3 are provided at both ends of the small diameter portions 11a and 11b. Connecting portions 12a and 12b to be connected are formed.

  Splines 13a and 13b splined to the constant velocity universal joints 2 and 3 and retaining ring grooves 14a for attaching axial retaining rings for the constant velocity universal joints to the connecting portions 12a and 12b, 14b is formed.

  A method for manufacturing the hollow power transmission shaft 1 having the above-described configuration will be described. First, a first hollow shaft 1A having a large diameter portion 10a and a small diameter portion 11a and a second hollow shaft 1B having a large diameter portion 10b and a small diameter portion 11b are formed. In this case, it can be formed by plastic working such as swaging or pressing.

  Moreover, the 1st hollow shaft 1A and the 2nd hollow shaft 1B can be made into the same size shape. For this reason, these can be shape | molded with the same plastic working tool.

  Then, as shown in FIG. 3, the end surface 16a of the large diameter portion 10a of the first hollow shaft 1A and the end surface 16b of the large diameter portion 10b of the second hollow shaft 1B are joined and integrated. That is, as shown by the arrows in FIG. 3, the end surface 16a of the large-diameter portion 10a of the first hollow shaft 1A is brought into contact with the end surface 16b of the large-diameter portion 10b of the second hollow shaft 1B. 15) Friction welding. The friction welding method is a kind of direct solid-phase joining method in which solids are joined without melting each other, and members to be joined (for example, metal or resin) are rubbed together at high speed, and the members are joined by frictional heat generated at that time. It is a method of joining by applying pressure simultaneously with softening. The advantages of this friction welding method are that no heat source other than frictional heat is required compared to arc welding or gas welding, that no welding rod or flux is required, no gas or spatter is generated during joining, For example, it is possible to obtain a product with high dimensional accuracy by a relatively simple operation and to assemble and join the finished members.

  Moreover, induction hardening is performed to the small diameter parts 11a and 11b of the first hollow shaft 1A and the second hollow shaft 1B to form a hardened surface layer. In this case, it may be stationary baking (induction hardening without moving the hardening coil) or moving baking (induction hardening with moving the hardening coil). Here, induction hardening is performed by causing induction current to be generated in the surface portion of the derivative (workpiece) by flowing a high frequency to generate heat, and the surface of the work piece is rapidly heated by this heat for quenching. Is the method.

  When forming a hardened surface layer, carburizing and quenching may be used. Here, the carburizing and quenching is a process of impregnating carbon from the surface layer by heating the steel for a long time in a carburizing agent such as a gas, liquid or solid containing a lot of activated carbon. In the case of carburizing and quenching, it is necessary to protect the vicinity of the joint 15.

  Thus, in the hollow power transmission shaft 1 of the first embodiment, a hollow power transmission shaft can be formed by two hollow shafts. Production is possible without incurring new capital investment. In addition, since the interior can be made hollow over the entire length of the shaft, if this shaft is used for a drive shaft (drive shaft), a propeller shaft (propulsion shaft) or the like that constitutes a power transmission system of an automobile, This can contribute to weight reduction, torsional rigidity and NVH characteristics.

  By making the joining between the respective end faces a friction welding, a good joining can be obtained and the joining time can be shortened. For this reason, each shaft can be integrally joined with high strength, and it is advantageous for automation and mass production.

  By forming each of the shafts 1A and 1B by plastic working such as swaging or press working, the material cost can be reduced compared to the cutting work, which contributes to the weight reduction of the shaft 1.

  There is no need to manufacture two types of the first hollow shaft and the second hollow shaft, and a plastic working tool or the like used in manufacturing the first hollow shaft and the second hollow shaft can be shared. For this reason, omission of the tool for plastic working and improvement of productivity can be aimed at, and processing cost can be reduced.

  Since the strength of the small diameter portion, which is the weakest portion in terms of strength when viewed from the entire shaft, can be increased, the entire shaft has high strength and excellent durability.

  FIG. 4 is a partial cross-sectional view of the hollow power transmission shaft 1 showing a modification of the first embodiment. In the first hollow shaft 1A and the second hollow shaft 1B, intermediate diameter portions 20a and 20b are formed between the small diameter portions 11a and 11b and the large diameter portions 10a and 10b, respectively.

  The large-diameter portions 10a and 10b and the medium-diameter portions 20a and 20b are continuous via tapered surfaces 23a and 23b that are reduced in diameter toward both ends in the axial direction, and the medium-diameter portions 20a and 20b and the small-diameter portion 11a 11b is continuous via taper surfaces 21a and 21b that reduce in diameter from the large diameter portions 10a and 10b toward the medium diameter portions 20a and 20b.

  Even in the hollow power transmission shaft 1 having the above-described configuration, a contact surface (joint portion) between the end surface 16a of the large-diameter portion 10a of the first hollow shaft 1A and the end surface 16b of the large-diameter portion 10b of the second hollow shaft 1B. 15) are joined and integrated by friction welding.

  In this case, the diameters of the large diameter portions 10a and 10b are larger than the diameters of the large diameter portions 10a and 10b of the first embodiment. For this reason, in applications that require higher strength, the present invention can be applied to increasing the diameter of the joint portion 15 that cannot be quenched or increasing the thickness of the weakest portions (small diameter portions 11a and 11b). In the hollow power transmission shaft 1 shown in FIG. 4, the same components as those of the hollow power transmission shaft shown in FIG.

  Next, FIG. 5 shows a second embodiment, which includes a first hollow shaft 1A and a second hollow shaft 1B having small diameter portions 11a and 11b and large diameter portions 10a and 10b. A hollow intermediate large-diameter shaft 24 is disposed over the entire length between the diameter portion 10a and the large-diameter portion 10b of the second hollow shaft 1B, so that the end surfaces of the large-diameter portions 10a and 10b and the intermediate large surface facing this end face. Each end face of the diameter shaft 24 is joined and integrated.

  That is, the end surface 16a of the large-diameter portion 10a of the first hollow shaft 1A is brought into contact with one end surface of the intermediate large-diameter shaft 24, and the end surface 16b of the large-diameter portion 10b of the second hollow shaft 1B is brought into contact with the intermediate large-diameter shaft. The abutting surfaces (joining portions 25a and 25b) are friction-welded to the other end surface of 24, respectively.

  For this reason, the hollow power transmission shaft of the second embodiment has the same operational effects as the first embodiment. In particular, since the intermediate large-diameter shaft 24 is disposed between the large-diameter portion 10a of the first hollow shaft 1A and the large-diameter portion 10b of the second hollow shaft 1B, three hollow power transmission shafts 1 are provided. It will consist of a hollow shaft. As a result, a longer hollow shaft can be formed, and the interior can be hollow over the entire length of the shaft. In the hollow power transmission shaft shown in FIG. 5, the same components as those of the hollow power transmission shaft shown in FIG.

  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. For example, as a joining method of each shaft, a joining method other than friction joining, For example, arc welding, TIG welding, MIG welding, MAG welding, laser welding, electron beam welding, gas welding, and the like may be used. In the embodiment, the hardened layer is formed only on the small diameter portions 11a and 11b of the first hollow shaft 1A and the second hollow shaft 1B. However, induction hardening may be performed as a whole. Further, the first hollow shaft 1A and the second hollow shaft 1B may not have the same shape.

It is a side view which shows the power transmission mechanism of a motor vehicle. It is a partial cross section figure of the hollow-shaped power transmission shaft which shows the 1st Embodiment of this invention. It is a partial cross section figure which shows the state before joining of the 1st hollow shaft and 2nd hollow shaft of the said hollow-shaped power transmission shaft. It is a partial sectional view showing a modification of the hollow power transmission shaft. It is a partial cross section figure of the hollow-shaped power transmission shaft which shows the 2nd Embodiment of this invention. It is a side view which shows the power transmission mechanism of the conventional motor vehicle. It is a partial cross section figure of the conventional shaft. It is a fragmentary sectional view of the other conventional shaft. It is a partial cross section figure of other conventional shafts.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 1A 1st hollow shaft 2A 2nd hollow shaft 10a, 10b Large diameter part 11a, 11b Small diameter part 16 Large diameter part end surface 24 Middle large diameter axis

Claims (6)

Comprising a first hollow shaft and a second hollow shaft having a small diameter portion and a large diameter portion;
The first hollow shaft and the second hollow shaft are each made hollow over their entire length, and the end surface of the large diameter portion of the first hollow shaft and the end surface of the large diameter portion of the second hollow shaft are joined and integrated, and an axially intermediate portion The hollow power transmission shaft is characterized in that the large-diameter portion is disposed at the end and the small-diameter portion is disposed at the end in the axial direction. Comprising a first hollow shaft and a second hollow shaft having a small diameter portion and a large diameter portion;
The first hollow shaft and the second hollow shaft are hollow over the entire length, and a hollow intermediate large-diameter shaft is disposed over the entire length between the large diameter portion of the first hollow shaft and the large diameter portion of the second hollow portion. The end face of each large diameter portion and each end face of the intermediate large diameter shaft facing this are joined and integrated, and the intermediate large diameter shaft is disposed at the axial intermediate portion and the small diameter is disposed at the axial end portion. A hollow power transmission shaft characterized in that a portion is disposed.   The hollow power transmission shaft according to claim 1 or 2, wherein the joining between the end faces is friction welding.   The hollow power transmission shaft according to any one of claims 1 to 3, wherein each of the shafts is formed by plastic working.   The hollow power transmission shaft according to any one of claims 1 to 4, wherein the first hollow shaft and the second hollow shaft have the same size and shape.   The hollow power transmission shaft according to any one of claims 1 to 5, wherein a hardened surface layer is formed by subjecting the small diameter portions of the first hollow shaft and the second hollow shaft to induction hardening.

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