JP2006064060A - Constant velocity universal joint - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To remarkably reduce weight of an external joint member structuring a constant velocity universal joint. <P>SOLUTION: Weight of the external joint member 4a of the constant velocity universal joint is reduced by bonding one end of a hollow long stem part 4a4 to an outside bottom part of a cup part 4a3 and forming a connection part 4a8 on the other end side of the long stem part 4a4. Strength is improved by heating the long stem part 4a4 of the external joint member 4a nearly over the whole in the axial direction thereof. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a constant velocity universal joint.

  Generally, a constant velocity universal joint is used for an application of transmitting torque in a state where an angular displacement is taken between two axes, such as a drive shaft, a propeller shaft, and a steering shaft of an automobile.

  FIG. 4 shows a power transmission system 1 from an automobile speed reducer (differential) to a drive wheel. A fixed type constant velocity universal joint 3 is arranged on the outboard side (drive wheel side) of the drive shaft 2. A sliding type constant velocity universal joint 4 is disposed on the inboard side (the reduction gear side) of the drive shaft 2.

  The fixed type constant velocity universal joint 3 includes an outer joint member 3a in which a long stem portion 3a4 is integrally joined to an outer bottom portion of a cup portion 3a3 in which a plurality of track grooves 3a2 are formed on a spherical inner diameter surface 3a1, and a spherical outer diameter surface 3b1. And an inner joint member 3b inserted into the cup portion 3a3 of the outer joint member 3a by spline fitting to the drive shaft 2, and a track groove 3a2 of the outer joint member 3a. Between the outer joint member 3a and the inner joint member 3b, and a plurality of balls 3c as torque transmitting members disposed in each of the ball tracks formed between the track grooves 3b2 of the inner joint member 3b. And a cage 3d for holding a plurality of balls 3c, and transmitting torque while allowing axial angular displacement of the outer joint member 3a and the inner joint member 3b. A.

  On the other hand, the sliding type constant velocity universal joint 4 in FIG. 4 is a so-called tripod type constant velocity universal joint, and includes three track grooves 4a2 extending in the axial direction on the cylindrical inner surface 4a1 (for convenience, only one track groove 4a2 is provided. The outer joint member 4a in which the long stem portion 4a4 is integrally joined to the outer bottom portion of the cup portion 4a3 in which the cup portion 4a3 is formed, and three leg shafts 4b1 in the radial direction (for convenience, only one leg shaft 4b1 is attached). The inner joint member 4b projecting from the inner joint member 4b, and the torque that is fitted on each leg shaft 4b1 of the inner joint member 4b and is rotatably inserted into the track groove 4a2 of the outer joint member 4a. It includes a roller 4c as a transmission means, and transmits torque while allowing axial angular displacement and relative movement of the outer joint member 4a and the inner joint member 4b.

  In FIG. 4, reference numerals 3e and 4d are boots for sealing the inside of the joint, and are for preventing leakage of the lubricant filled in the joint and entry of foreign matter into the joint.

  By the way, in the power transmission system 1 shown in FIG. 4, the long stem portion 4a4 of the sliding type constant velocity universal joint 4 disposed on the inboard side increases the outer diameter to increase the rigidity, while reducing the weight. It may be hollow for the purpose of illustration (see, for example, Patent Document 1).

  FIG. 5 shows an example of the outer joint member 4a of the sliding type constant velocity universal joint 4 disposed on the inboard side. The outer joint member 4a is obtained by integrally joining three members, that is, a cup portion 4a3, a pipe 4a5, and a stub 4a6 by friction welding or laser welding. A stem 4a7 for joining the pipe 4a5 protrudes from the outer bottom of the cup portion 4a3. The pipe 4a5 and the stub 4a6 are members constituting the long stem portion 4a4. The stub 4a6 has a connecting portion 4a8 in which a spline or a serration is formed on the outer diameter surface of the outer end portion.

  As described above, conventionally, the pipe 4a5 is used as a constituent element of the long stem portion 4a4, thereby reducing the hollow weight of the outer joint member 4a.

Please tell me the prior art gazette number.

  Incidentally, the outer joint member 4a shown in FIG. 5 is usually subjected to heat treatment such as induction hardening as shown by the mesh in the drawing in order to increase its strength. However, the pipe 4a5 is often used as a raw material without being subjected to heat treatment since it may cause a decrease in strength of the joint portion between the cup portion 4a3 and the stub 4a6 when heat treatment is performed. To ensure the desired strength. For this reason, it is difficult to achieve sufficient weight reduction of the outer joint member 4a.

  Conventionally, the number of parts of the outer joint member 4a is three, and two places must be joined, so that the manufacturing cost tends to increase.

  The present invention was devised in view of such circumstances, and its purpose is to further increase the strength and weight of the outer joint member constituting the constant velocity universal joint, and to improve the outer joint member. The purpose is to reduce costs by reducing the number of parts.

  The constant velocity universal joint according to the present invention includes an outer joint member in which one end of a long stem portion is joined to an outer bottom portion of a cup portion in which a plurality of track grooves are formed on an inner diameter surface, and an outer joint, An outer joint member comprising: an inner joint member inserted into a cup portion of the member; and a torque transmission member that transmits torque by being interposed between the track groove of the cup portion and the inner joint member. The long stem portion is formed into a hollow shape, and a connecting portion for power transmission is formed on the other end side of the long stem portion.

  The constant velocity universal joint of the present invention is configured by joining two members, a cup part and a long stem part, to an outer joint member which has been conventionally constituted by joining three members of a cup part, a pipe and a stub. It is what. The long stem portion is hollow over the entire region, and a connecting portion for transmitting power is provided at an end portion on the opposite side to the joint side with the cup portion. In the long stem portion, by making a portion corresponding to the conventional stub hollow, further weight reduction can be achieved.

  Moreover, since the outer joint member is composed of two members, that is, a cup portion and a long stem portion, the number of parts is reduced as compared with the prior art, and the number of joints between parts is reduced. Thereby, manufacturing cost can be reduced.

The said structure WHEREIN: By making one end side outer diameter into the maximum diameter among the outer diameters of a long stem part, the intensity | strength of a junction part with a cup part can be raised.

  In addition, the constant velocity universal joint of the present invention is such that the joint portion of the long stem portion is only the joint portion with the cup portion, so that the hollow portion extends from the end on the coupling portion side of the long stem portion to the vicinity of the end on the cup portion side. It becomes possible to apply heat treatment over almost the entire area. As described above, when the heat treatment is performed on the hollow portion of the long stem portion, the strength of the long stem portion is increased. Therefore, the thickness of the long stem portion can be reduced to further reduce the weight.

  As described above, the present invention includes an outer joint member in which one end of the long stem portion is joined to the outer bottom portion of the cup portion, and the long stem portion of the outer joint member is formed into a hollow shape. Weight reduction can be achieved. In addition, since the connecting portion for power transmission is formed on the other end side of the long stem portion, the number of parts of the outer joint member is reduced from the previous three points to two points, the manufacturing cost of the parts themselves, and Further, it is possible to reduce the cost required for the joining work between the parts.

  Hereinafter, an embodiment of a constant velocity universal joint according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an example of an outer joint member 4a which is one of the components of the constant velocity universal joint according to this embodiment. The outer joint member 4a constitutes the sliding type constant velocity universal joint 4 disposed on the inboard side of the drive shaft 2, for example, as in the conventional example of FIG. The other components of the sliding type constant velocity universal joint 4, that is, the inner joint member 4 b and the roller 4 c (torque transmission member) may be the same as those in the conventional example, and illustration and description thereof are omitted.

  The outer joint member 4a is obtained by joining one end of the long stem portion 4a4 to the cup portion 4a3. The cup part 4a3 is formed with three track grooves (see reference numeral 4a2 in FIG. 4) extending in the axial direction on a cylindrical inner surface (not shown) (see reference numeral 4a1 in FIG. 4), and a stem 4a7 protruding from the outer bottom. It is a member. The long stem portion 4a4 is formed, for example, by drawing a hollow element pipe such as swaging to a predetermined shape. Since the long stem portion 4a4 is joined at one end side to the stem 4a7 of the cup portion 4a3 by friction welding or laser welding or the like, it is formed to have substantially the same diameter as the stem 4a7 of the cup portion 4a3, and the other end side is drawn by drawing. It has a smaller diameter than the side. A connecting portion 4a8 for power transmission is provided at the other end of the long stem portion 4a4. In this embodiment, splines are formed on the outer diameter surface of the connecting portion 4a8.

  In addition, the mesh in the figure indicates a hardened layer formed by heat treatment such as induction hardening. In the long stem portion 4a4, a hardened surface layer is formed in the most part from the vicinity of the joining side end portion to the cup portion 4a3 to the other end portion. As described above, when the long stem portion 4a4 is heat-treated, the strength of the long stem portion 4a4 is increased. Therefore, the outer joint member 4a can be further reduced in weight through the thinning of the long stem portion 4a4.

  As described above, the outer joint member 4a has the long stem portion 4a4 formed in a hollow shape over the entire area, and the long stem portion 4a4 can be thinned. It is possible to further reduce the weight of the quick universal joint. Moreover, since the outer joint member 4a is comprised by two members, the cup part 4a3 and the long stem part 4a4, the number of parts reduces compared with the past, and also the joint location of components reduces to one place. . Thereby, manufacturing cost can be reduced.

  FIG. 2 shows another embodiment of the outer joint member 4a. This outer joint member 4a has the outer diameter of one end side of the outer diameter of the long stem portion 4a4 as the maximum diameter, and the outer diameter of the joint portion between the stem 4a7 of the cup portion 4a3 and the long stem portion 4a4 is set to that of the long stem portion 4a4. The outer joint member 4a shown in FIG. 1 is different from the outer joint member 4a in that it has a larger diameter than the central portion.

  The outer joint member 4a in FIG. 2 has an outer diameter of the joint portion between the stem 4a7 of the cup portion 4a3 and the long stem portion 4a4 larger than that of the central portion of the long stem portion 4a4. Bonding strength with the part 4a4 is increased. Thereby, the thickness of the center part of long stem part 4a4 can be made still thinner, and further weight reduction of outer joint member 4a and by extension, a constant velocity universal joint can be attained.

  As mentioned above, although it demonstrated per embodiment of this invention, this invention is not limited to the said embodiment, A various deformation | transformation is possible, for example, in FIG.1 and FIG.2, from the outer surface of the long stem part 4a4. A hardened layer is formed in a region of a predetermined depth, and an uncured layer is left on the inner surface side. However, as shown in FIGS. 3 (A) and 3 (B), from the outer surface of the long stem portion 4a4 to the inner surface A hardened layer may be formed in the entire depth region.

  In the above embodiment, the sliding type constant velocity universal joint 4 disposed on the inboard side of the drive shaft 2 is described as an example. However, the present invention is not limited to the inboard side of the drive shaft 2. The present invention can be applied to a constant velocity universal joint used for other purposes.

  In the above embodiment, the tripod type constant velocity universal joint 4 which is a kind of sliding type is described as an example. However, the present invention is not limited to the sliding type and the fixed type. It can also be applied to fast universal joints.

It is a half sectional view showing an outer joint member which is a component of a constant velocity universal joint according to an embodiment. It is a half sectional view showing an outer joint member which is a component of a constant velocity universal joint according to another embodiment. 3A is a modification of the outer joint member of FIG. 1, and FIG. 3B shows a modification of the outer joint member of FIG. It is the schematic which shows the power transmission system of a motor vehicle. It is a half sectional view showing an example of an outer joint member which is a component of a conventional constant velocity universal joint.

Explanation of symbols

4a Outer joint member 4a1 Cylindrical inner diameter surface 4a2 Track groove 4a3 Cup portion 4a4 Long stem portion 4a5 Pipe 4a6 Stub 4a7 Stem 4a8 Connecting portion 4b Inner joint member 4b1 Leg shaft 4c Roller

Claims (3)

  An outer joint member in which one end of the long stem portion is joined to the outer bottom portion of the cup portion having a plurality of track grooves formed on the inner diameter surface, an inner joint member inserted into the cup portion of the outer joint member, In a constant velocity universal joint provided with a torque transmission member that transmits torque between the track groove and the inner joint member, the long stem portion of the outer joint member is formed in a hollow shape, and A constant velocity universal joint characterized in that a connecting portion for power transmission is formed on the end side.   2. The constant velocity universal joint according to claim 1, wherein the outer diameter of the long stem portion has an outer diameter on one end side as a maximum diameter.   The constant velocity universal joint according to claim 1, wherein the long stem portion is heat-treated.

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