JP5921918B2 - Method for manufacturing outer joint member for constant velocity universal joint - Google Patents

Description

  The present invention is used in, for example, power transmission systems of automobiles, aircraft, ships, various industrial machines, etc., and is an outer joint for a constant velocity universal joint that transmits rotational power at a constant speed between two axes of a driving side and a driven side. The present invention relates to a method for manufacturing a member.

  As is well known, constant velocity universal joints are broadly classified into fixed constant velocity universal joints that allow only angular displacement and sliding constant velocity universal joints that allow angular displacement and axial displacement. Regardless of whether the constant velocity universal joint is a fixed type or a sliding type, the constant velocity universal joint has a cup portion that is open at one end, and is provided with a plurality of track grooves extending in the axial direction on the inner diameter surface of the cup portion. A joint member and joint internal parts such as an inner joint member and a torque transmission member housed on the inner periphery of the cup portion of the outer joint member are provided as main constituent members. Out of these joint components, the outer joint members are manufactured using machining such as cutting and turning, and plastic processing such as forging. However, as much as possible in order to improve production efficiency and yield. Processing is often adopted.

  As an example, the following Patent Document 1 discloses an outer joint member of a tripod type constant velocity universal joint, which is a kind of sliding type constant velocity universal joint, in particular, a plurality of straight lines having one end opened and extending in the axial direction on the inner diameter surface. Describes a method of manufacturing an outer joint member integrally including a cup portion provided with a track groove and a shaft portion extending axially outward from the other end of the cup portion through various forging processes. Specifically, a pre-forging step for obtaining an intermediate forged product having a cup-shaped portion having a track groove roughly formed on an inner diameter surface from a rod-shaped material by sequentially performing upsetting, forward extrusion, backward extrusion, and the like, And an ironing process for obtaining a final forged product in which track grooves are formed into a finished shape (finished product shape) by subjecting the cup-shaped portion of the forged product to ironing.

  The manufacturing method (procedure) described above produces not only the outer joint member for the sliding type constant velocity universal joint but also the outer joint member for the fixed type constant velocity universal joint represented by the undercut free type. In this case, it can be preferably applied.

JP 2002-213476 A

  By the way, when the outer joint member is obtained by following the above procedure, the opening end surface 102 of the cup-shaped portion 101 of the final forged product 100 is formed with the track groove 103 as shown in FIG. When the region and the region between the track grooves 103 are often undulated so as to be convex and concave, respectively, and as a result, the required cup depth cannot be secured over the entire circumference. There is. As a countermeasure, at present, after obtaining the intermediate forged product, and finally the final forged product 100, using a relatively large rod-shaped material, by turning a predetermined amount of the open end surface 102 of the cup-shaped portion 101 where waviness has occurred, The final forged product 100 of the outer joint member that secures the required cup depth over the entire circumference is obtained. However, if this is done, there is a problem that it is not possible to effectively increase productivity because a large end surface finish is essential, and it is necessary to use a bar material larger than necessary, resulting in a decrease in yield. Invite

  The waviness that occurs on the open end face 102 of the cup-shaped portion 101 of the final forged product 100 is that the thickness reduction rate of the cup-shaped portion of the intermediate forged product due to ironing differs between each circumferential portion of the cup-shaped portion of the intermediate forged product. That is, as shown in FIG. 9B, it is considered that the main factor is that the thickness of the cup-shaped portion 101 ′ of the intermediate forged product 100 ′ used for ironing is different in each portion in the circumferential direction. . Therefore, it is considered that the above problem can be alleviated or eliminated by designing the product so that the difference in thickness between the circumferential portions of the cup portion of the outer joint member is reduced. However, since the thickness of each part in the circumferential direction of the cup portion of the outer joint member is determined in consideration of the function and performance of the constant velocity universal joint, it cannot be easily changed.

  In view of such circumstances, the object of the present invention is to improve the productivity and yield of the outer joint member, which is a component of the constant velocity universal joint, without affecting the function and performance of the constant velocity universal joint. Therefore, it contributes to the cost reduction of the constant velocity universal joint.

The present invention, which was created to achieve the above object, has an outer joint for a constant velocity universal joint having a cup portion having one open end and a plurality of track grooves extending in the axial direction on the inner diameter surface of the cup portion. A method of manufacturing a member, wherein a forging step is performed to obtain an intermediate forged product having a cup-shaped portion having a track groove roughly formed on an inner diameter surface from a rod-shaped material, and an inner diameter surface is obtained by subjecting the intermediate forged product to ironing. And a squeezing step for obtaining a final forged product having a cup-shaped portion in which track grooves are formed into a finished shape, and in the pre-forging step, the undulation generated on the opening end surface of the cup-shaped portion of the final forged product in accordance with the ironing Is a concave-convex shape portion in which the arrangement of the concave portion and the convex portion is opposite, and the concave-convex shape portion in which the circumferential region in which the concave portion is provided coincides with the circumferential region in which the track grooves are roughly formed is a cup-shaped portion. molding the open end of the Characterized in that the obtaining an intermediate forged product.

  In this way, the degree of undulation that occurs on the opening end face of the final forged product due to the ironing process is reduced without incurring a special increase in processing cost (the difference in height between the concave and convex parts constituting the undulation is reduced. )be able to. This makes it possible to improve the productivity by reducing the end face finishing amount (turning amount) of the final forged product, and it is possible to use a rod-like material having a volume that is small enough to reduce the end face finishing amount, Yield can be improved. In particular, if the degree of undulation is greatly reduced, it is possible to omit the end face finishing for the final forged product. Further, if the configuration of the present invention is adopted, it is not necessary to change the thickness of each part in the circumferential direction of the cup part in product design, so that the function and performance of the constant velocity universal joint are not affected. From the above, according to the present invention, the productivity and yield of the outer joint member, which is one of its constituent members, can be improved without making design changes that affect the function and performance of the constant velocity universal joint. Therefore, it can contribute to the cost reduction of the constant velocity universal joint.

  The cup portion of the outer joint member is generally configured by alternately arranging thin portions and thick portions in the circumferential direction, and the track groove (the bottom surface of the groove) is an inner diameter surface of the thin portion. Generally composed. Furthermore, the thickness reduction rate (the amount of axial deformation in the axial direction) associated with the ironing process is larger in the relatively thin portion than in the relatively thick portion. Therefore, in the pre-forging step, an intermediate forged product having a cup-shaped portion in which a circumferential region in which the track groove is roughly formed and a circumferential region in which the concave portion of the concavo-convex shape portion is molded is matched is obtained. Is desirable. Thereby, the amount of waviness of the open end face of the final forged product can be effectively reduced.

  The pre-forging process is generally configured to include a plurality of forging steps. Then, at the same time as forming the cup-shaped portion having the track groove that is roughly formed in the final forging step (for example, backward extrusion), the above-mentioned uneven shape portion can be molded. At this time, the concavo-convex shape portion may be molded by a molding die portion provided in the track groove rough molding punch, or a molding die portion provided in a molding die different from the track groove rough molding punch. You may make it mold by.

  Further, the molding of the concavo-convex shape portion and the shaping of the cup-shaped portion having the track groove roughly formed on the inner diameter surface may be performed in separate forging steps. Specifically, it is possible to obtain a cup-shaped portion having a track groove roughly formed on the inner diameter surface in a forging step after molding the uneven portion.

  The present invention can also be preferably applied when manufacturing an outer joint member integrally having a shaft portion extending axially outward from the other end of the cup portion.

  The present invention provides an outer joint member in which each track groove is composed only of a straight portion, for example, a sliding type represented by a tripod type constant velocity universal joint (TJ), a double offset type constant velocity universal joint (DOJ), and the like. It can be applied when manufacturing an outer joint member for a quick universal joint. Further, according to the present invention, each track groove is relatively positioned on the linear portion positioned on one end side (opening end portion side) of the cup portion and relatively on the other end side (counter opening end portion side) of the cup portion. It may be applied when manufacturing an outer joint member composed of an arcuate portion positioned, for example, an outer joint member for an undercut-free constant velocity universal joint (UJ), which is a kind of a fixed constant velocity universal joint. it can.

  As described above, according to the present invention, the productivity and yield of the outer joint member, which is a component of the constant velocity universal joint, are improved without affecting the function and performance of the constant velocity universal joint. be able to. Thereby, it can contribute to the cost reduction of a constant velocity universal joint.

(A) is a schematic sectional drawing of the constant velocity universal joint provided with the outer joint member manufactured using the manufacturing method which concerns on one Embodiment of this invention. (A)-(c) figure is a schematic side view of the intermediate product obtained by each forging process of a pre-forging process, (d) figure is a schematic side view of the intermediate forging product obtained by the final forging process of a pre-forging process. It is. (A) is a schematic front view of an intermediate forged product, and (b) is a side view of the intermediate forged product including a schematic cross-sectional view taken along the line XX in FIG. It is sectional drawing which shows typically the last forge process in a forge process. It is a side view of the final forging product containing a partial cross section. It is sectional drawing which shows typically the final forge processing process which concerns on other embodiment. It is a figure which shows typically the manufacturing method which concerns on other embodiment of this invention, (a) A figure is sectional drawing which shows a 3rd forge process typically among pre-forging processes, (b) A figure is pre-forging. It is sectional drawing which shows the final forge process typically among processes. Both (a) figure and (b) figure are the partial side views of the intermediate forging product which concerns on other embodiment. (A) The figure is a side view including the partial cross section of the final forging product of the outer joint member manufactured by the conventional method, (b) The figure is the intermediate forging formed into the final forging product shown in (a) figure It is a front view of goods.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, for the sake of convenience, a constant velocity universal joint including an outer joint member manufactured using a manufacturing method according to an embodiment of the present invention will be described with reference to FIG. One Embodiment of the manufacturing method of an outer joint member is described based on FIGS.

  In FIG. 1, the constant velocity universal joint A provided with the outer joint member manufactured using the manufacturing method which concerns on one Embodiment of this invention is shown. The constant velocity universal joint A shown in the figure is a six-ball type undercut-free constant velocity universal joint (UJ) which is a kind of a fixed constant velocity universal joint that allows only angular displacement, and includes a cup portion 2. And the outer joint member 1 which has the axial part 3 integrally, the inner joint member 20 accommodated in the inner periphery of the cup part 2, and the six balls 30 arrange | positioned between the cup part 2 and the inner joint member 20 And a cage 31 that is disposed between the inner diameter surface 4 of the cup portion 2 and the outer diameter surface 21 of the inner joint member 20 and holds the balls 30 at predetermined intervals in the circumferential direction. The number of balls 30 arranged may be 8, 10, or 12.

  A shaft 32 is connected to the inner periphery of the inner joint member 20 by, for example, spline fitting, and one end and the other end of a bellows-like boot 33 are connected to the shaft 32 and the cup portion 2 of the outer joint member 1. Each is fixed. By fixing the boot 33 in this manner, external leakage of grease (lubricant) enclosed in the joint and further entry of foreign matter into the joint is prevented as much as possible.

  Track grooves 5 and 22 extending in the axial direction are provided at a 60 ° pitch on the inner diameter surface 4 of the cup portion 2 of the outer joint member 1 and the outer diameter surface 21 of the inner joint member 20. A ball 30 is disposed in each of the ball tracks formed by the track grooves 5 and 22 forming a pair of the inner joint members 20. The track groove 5 of the outer joint member 1 is composed of a linear portion located on the opening end side of the cup portion 2 and an arc-shaped portion located on the side opposite to the opening end of the cup portion 2, and the inner joint member 20. The track groove 22 is composed of an arc-shaped portion located on the opening end side of the cup portion 2 and a linear portion located on the side opposite to the opening end of the cup portion 2. The center of curvature of the arc-shaped portion of the track groove 5 of the outer joint member 1 and the center of curvature of the curved portion of the track groove 22 of the inner joint member 20 are offset equidistantly from each other in the axially opposite direction with respect to the joint center O. It is in. Although a cross-sectional view perpendicular to the axis is omitted, the cup portion 2 is configured by alternately arranging six thicker portions 6 and six relatively thin portions 7 in the circumferential direction. The track groove 5 (the groove bottom surface) is constituted by the inner diameter surface of the thin portion 7.

  Hereinafter, it is one Embodiment about the manufacturing method of the outer joint member which concerns on this invention, Comprising: The method for manufacturing the outer joint member 1 described above is demonstrated. Roughly speaking, the outer joint member 1 includes a pre-forging step for obtaining an intermediate forged product 1 ″ shown in FIGS. 2 (d), 3 (a) and 3 (b), and a final forged product 1 ′ shown in FIG. The final forging product 1 ′ is finished through an ironing step, a finishing step for finishing each part of the final forged product 1 ′ into a finished product shape, and a heat treatment step for applying a heat treatment to the final forged product 1 ′ finished into the finished product shape.

  In the pre-forging process, the cup-shaped portion 2 ″ shown in FIGS. 2 (d), 3 (a), and 3 (b) is formed from a rod-shaped material (not shown) through a plurality of forging steps (four steps in this embodiment). An intermediate forged product 1 ″ provided is obtained. Specifically, first, by performing upsetting on a rod-like material (not shown) in the first forging step, as shown in FIG. Get. Next, by performing forward extrusion processing on the first intermediate product M1 in the second forging step, as shown in FIG. A second intermediate product M2 having a relatively small-diameter shaft-like portion 3 ′ (a portion finally finished to the shaft portion 3) on the end side (the side on which the outer peripheral edge portion is rounded) is obtained. Next, in the third forging step, upsetting is performed on the large diameter portion of the second intermediate product M2, and the large diameter portion is compressed and deformed in the axial direction and expanded and deformed in the radial direction, thereby FIG. 2 (c). As shown in FIG. 3, a third intermediate product M3 having the upsetting portion 10 and the shaft-like portion 3 ′ is obtained. Then, in the fourth forging step as the final forging step, by performing backward extrusion processing on the upset portion 10 of the third intermediate product M3, FIG. 2 (d) and FIG. 3 (a) (b) As shown, an intermediate forged product 1 ″ having a cup-shaped portion 2 ″ is obtained.

  As shown in FIG. 3A, the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ is configured by alternately arranging the thick portions 11 and the thin portions 12 in the circumferential direction. A track groove 5 ″ is roughly formed on the surface. The cup-shaped portion 2 ″ is thicker and shorter in the axial direction than the cup portion 2 of the outer joint member 1 shown in FIG. Accordingly, the track groove 5 ″ roughly formed on the inner diameter surface of the cup-shaped portion 2 ″ is shorter in the axial direction than the track groove 5 provided on the inner diameter surface 4 of the cup portion 2 of the outer joint member 1.

  The opening end face 13 of the cup-shaped portion 2 ″ has an uneven shape portion 14 formed by alternately arranging recesses 15 and protrusions 16 in the circumferential direction. This uneven shape portion 14 is cupped in an ironing process to be described later. When the final forged product 1 ′ (see FIG. 5) having a cup-shaped portion 2 ′ having a longer axial dimension than the cup-shaped portion 2 ″ is obtained by ironing the shape-shaped portion 2 ″. It is provided in order to reduce the degree of waviness that occurs on the open end surface (open end) of the cup-shaped portion 2 ′ of the forged product 1 ′, that is, to obtain a cup-shaped portion 2 ′ having a substantially flat open end surface. Therefore, the arrangement mode of the concave portion 15 and the convex portion 16 constituting the concave-convex shape portion 14 is opposite to the concave / convex mode of waviness generated on the opening end surface of the cup-shaped portion 2 ′ of the final forged product 1 ′.

  In general, when ironing is performed on a cylindrical workpiece, the axial deformation amount (thickness reduction rate) of the workpiece due to ironing is greater in the thin portion than in the thick portion. Therefore, when ironing is performed on the cup-shaped portion of the intermediate forged product in which the opening end surface is formed flat without the uneven portion 14 described above, the opening end surface of the cup-shaped portion of the final forged product is as shown in FIG. As shown to (a), it becomes convex shape and concave shape in the formation area of a thin part and a thick part, respectively. Accordingly, the concave portion 15 constituting the concavo-convex shape portion 14 is a formation region of the thin portion 12 constituting the cup-shaped portion 2 ″ (region having a roughly formed track groove 5 ″ in the inner diameter surface of the cup-shaped portion 2 ″). On the other hand, the convex portion 16 is provided with a region where the thick portion 11 constituting the cup-shaped portion 2 ″ is formed (the region between the roughly formed track grooves 5 ″, 5 ″ of the inner diameter surface of the cup-shaped portion 2 ″). From the above-described function of the concavo-convex shape portion 14, the depth dimension of the concave portion 15 (the height difference between the bottom portion of the concave portion 15 and the top portion of the convex portion 16) is the thickness of the cup-shaped portion 2 ″ accompanying the ironing process. It is set approximately equal to the difference in the amount of expansion deformation between the meat portion 11 and the thin portion 12, and is arbitrarily set within a range of 0.1 mm to 10 mm in consideration of processing conditions and the like. In the present embodiment, the concave portion 15 is configured by providing a concave curved surface having a partial cylindrical surface on the opening end surface 13 of the cup-shaped portion 2 ″.

  The concave-convex shaped portion 14 is molded at the same time as the cup-shaped portion 2 ″ (intermediate forged product 1 ″) having the track grooves 5 ″ roughly formed on the inner surface is formed. Here, FIG. Corresponding to the concavo-convex shape portion 14 in the punch 52 for obtaining the cup-shaped portion 2 ″ having the roughly formed track groove 5 ″ out of the forging die for performing the backward extrusion processing on the third intermediate product M3 shown in the figure. The mold part N (shown by cross-hatching in the drawing, which is the same in the embodiments described later) is provided.After the third intermediate product M3 is put into the die 51, When the punch 52 is moved relatively close and the third intermediate product M3 is subjected to a backward extrusion process, a cup-shaped portion 2 ″ having a track groove 5 ″ roughly formed on the inner diameter surface is obtained at the same time. Open end face 13 of the shaped part 2 " Concave-convex part 14 is molded.

  The intermediate forged product 1 ″ obtained as described above is transferred to the ironing process. Then, the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ is ironed to extend the cup-shaped portion 2 ″ in the axial direction. By deforming, a final forged product 1 ′ having a cup-shaped portion 2 ′ having a finished track groove 5 ′ formed on the inner diameter surface is obtained. Since the above-mentioned uneven shape portion 14 is provided on the opening end face 13 of the cup-shaped portion 2 '' of the intermediate forged product 1 "to be subjected to ironing, when the ironing is completed, as shown in FIG. A final forged product 1 ′ having a cup-shaped portion 2 ′ with less waviness at the open end face (open end face is substantially flat) is obtained.

  Then, the final forged product 1 ′ is transferred to the finishing process. In the finishing process, it is difficult to form by forging process (for example, an annular groove for fixing one end portion of the boot 33 to be provided on the outer diameter surface of the cup portion 2 or a free end outer diameter of the shaft portion 3. The final forged product 1 ′ is finished into a finished product shape by performing processing for forming a power spline, etc., and further, if necessary, processing for turning the opening end face of the cup-shaped portion 2 ′ by a predetermined amount. And the outer joint member 1 shown in FIG. 1 is completed by performing heat treatment, such as quenching, on the final forged product 1 ′, which has been finished into a finished product as a whole.

  As described above, in the method for manufacturing the outer joint member 1 according to the present invention, the final forged product is formed on the opening end surface 13 of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ along the ironing process in the pre-forging step. The concavo-convex shape portion 14 in which the arrangement of the concave portion and the convex portion is opposite to the undulation generated on the opening end face of the 1 ′ cup-shaped portion 2 ′ is molded. More specifically, in the pre-forging process, in consideration of the thickness reduction rate (axial deformation amount in the axial direction) due to ironing, it is made to coincide with the circumferential region where the coarsely formed track groove 5 ″ exists. Thus, the concave portion 15 of the concave and convex portion 14 was molded.

  In this way, the degree of undulation that occurs on the opening end face of the cup-shaped portion 2 ′ of the final forged product 1 ′ during ironing is reduced without causing a particular increase in processing costs (the concave and convex portions constituting the undulation). The height difference of the portion can be reduced). This makes it possible to improve the productivity by reducing the end face finishing amount (turning amount) of the final forged product 1 ′, and it is possible to use a rod-like material having a volume that is small enough to reduce the end face finishing amount. Thus, the yield can be improved. In particular, if the undulation generated on the opening end surface of the cup-shaped portion 2 ′ is so small that it can be ignored, the end surface finishing for the final forged product 1 ′ can be omitted. Further, if the configuration of the present invention is adopted, it is not necessary to change the wall thickness of each part in the circumferential direction of the cup portion 2 in product design, and therefore, the function and performance of the constant velocity universal joint A shown in FIG. Never reach. From the above, according to the present invention, the productivity and yield of the outer joint member 1 which is one of its constituent members can be improved without making a design change that affects the function and performance of the constant velocity universal joint A. Improvement can be achieved, thereby contributing to cost reduction of the constant velocity universal joint A.

  As mentioned above, although the manufacturing method of the outer joint member 1 which concerns on one Embodiment of this invention was demonstrated, this invention is not limitedly applied to said embodiment, Various in the range which does not deviate from the summary. It is possible to make changes.

  For example, in the above embodiment, as described with reference to FIG. 4, the punch 52 (a plurality of forgings included in the pre-forging step) for forming the inner surface of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″. Of the steps, the punch 52) used in the final forging step is provided with a forming die portion N for forming the concavo-convex shape portion 14 to form a cup-shaped portion 2 ″ having a roughly formed track groove 5 ″. At the same time, the concavo-convex shape portion 14 is molded on the opening end face 13 of the cup-shaped portion 2 ″. However, the molding die portion N for molding the concavo-convex shape portion 14 is punched as shown in FIG. You may make it provide in the metal mold | die 53 provided separately from 52. FIG.

  Further, it is not always necessary to mold the concavo-convex shape portion 14 at the same time as the cup-shaped portion 2 ″ is formed, and both may be formed in separate forging steps. For example, FIG. As shown in FIG. 3, among the forging dies used in the third forging step for obtaining the third intermediate product M3 having the upsetting portion 10, molding for forming the concavo-convex shape portion 14 on the end face of the punch 62 is performed. At the same time as forming the upsetting portion 10 using the punch 62 and the die 61, the concavo-convex shape portion 14 is formed on the end face (outer diameter side region) of the upsetting portion 10 by using the punch 62 and the die 61. A third intermediate product M3 is obtained, and then, as shown in Fig. 7 (b), a punch 52 and a die 51 that do not have a forming die portion N for forming the concavo-convex shape portion 14 are used. Back extrusion process to the third intermediate product M3 Subjected, to obtain "cup-shaped portion 2 having a" track grooves 5 that are rough molded on the inner diameter surface (intermediate forged product 1 ").

  Further, the form of the concave portion 15 constituting the concave-convex shape portion 14 is not limited to the above. In other words, in the above-described embodiment, the concave portion 15 is formed by the concave surface of the partial cylindrical surface provided on the opening end surface 13 of the cup-shaped portion 2 ″. For example, as shown in FIG. As shown in FIG. 8B, the recess 15 may be configured by combining an arc surface and a flat surface.

  Further, in the above, the present invention is applied when the pre-forging process is configured by four forging steps (when the intermediate forged product 1 ″ is obtained through four forging steps), the intermediate forged product 1 ″ is 3 or less or The present invention can also be preferably applied to the case where five or more forging steps are obtained.

  In addition, the case where the present invention is applied when manufacturing an outer joint member for a six-ball type undercut-free constant velocity universal joint (UJ), which is a kind of fixed type constant velocity universal joint, has been described above. However, in addition to the 6-ball type, the present invention can be preferably applied to the manufacture of UJ outer joint members for the 8-ball type, the 10-ball type, and the 12-ball type.

  Further, the present invention can be applied not only when manufacturing the outer joint member for the fixed type constant velocity universal joint as described above but also when manufacturing the outer joint member for the sliding type constant velocity universal joint. Is possible. Sliding constant velocity universal joints allow both angular displacement and axial displacement, and representative examples include tripod type constant velocity universal joints (TJ) and double offset type constant velocity universal joints (DOJ). It is done. In these outer joint members for sliding type constant velocity universal joints, generally, the track groove is constituted only by a linear portion.

1 outer joint member 1 'final forged product 1 "intermediate forged product 2 cup part 2' cup-shaped part 2" cup-shaped part 3 shaft part 3 'shaft-shaped part 5 track groove 5' track groove (roughly formed track groove)
DESCRIPTION OF SYMBOLS 11 Thick part 12 Thin part 13 Opening end surface 14 Concave and convex part 15 Concave part 16 Convex part 52 Punch (punch for rough molding)
62 Punch A Constant velocity universal joint M1 First intermediate product M2 Second intermediate product M3 Third intermediate product N Mold part

Claims (8)

A method of manufacturing an outer joint member for a constant velocity universal joint having a cup portion having one end opened and having a plurality of track grooves extending in an axial direction on an inner diameter surface of the cup portion,
From the rod-shaped material, a pre-forging process for obtaining an intermediate forged product having a cup-shaped portion having a track groove roughly formed on the inner diameter surface, and by applying ironing to the intermediate forged product, the track groove is formed into a finished shape on the inner diameter surface. An ironing step of obtaining a final forged product having a cup-shaped part,
In the pre-forging step, the undulation generated on the opening end surface of the cup-shaped portion of the final forged product with the ironing process is a concavo-convex shape portion opposite to the arrangement mode of the concave portion and the convex portion, and the concave portion is provided. For a constant velocity universal joint, characterized in that an intermediate forged product is obtained in which the concave and convex portions having the circumferential region coincided with the circumferential region in which the track grooves are roughly formed are molded on the opening end face of the cup-shaped portion . Manufacturing method of outer joint member. Said front forging step includes a plurality of forging step, in its final forging step, simultaneously with the molding of the cup-shaped portion having a track groove which is rough molded on the inner diameter surface, claim to molding the uneven portion 1 The manufacturing method of the outer joint member for constant velocity universal joints of description. The manufacturing method of the outer joint member for constant velocity universal joints of Claim 2 which molds the said uneven | corrugated shaped part with the shaping | molding die part provided in the punch for rough formation of a track groove. 3. The method for manufacturing an outer joint member for a constant velocity universal joint according to claim 2 , wherein the concavo-convex shape portion is molded by a molding die portion provided on a molding die different from the rough molding punch for the track groove. It said front forging step includes a plurality of forging step, and molding of the concave and convex portion, in claim 1 to perform the forming of the cup-shaped portion having a track groove which is rough molded on the inner diameter surface in a separate forging step The manufacturing method of the outer joint member for constant velocity universal joints of description. The manufacturing method of the outer joint member for constant velocity universal joints of Claim 5 which obtains the cup-shaped part which has the track groove roughly formed in the internal-diameter surface by the forging step after mold-molding the said uneven | corrugated shaped part. The manufacturing method of the outer joint member for constant velocity universal joints as described in any one of Claims 1-6 applied to what a track groove comprises only a linear part. Track groove, the linear portion located relatively one end, according to any one of claim 1 to 6, applicable to be composed of an arcuate portion located relatively other end Manufacturing method for outer joint member for constant velocity universal joint.

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