JP5912694B2 - 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 member manufacturing method and an outer joint 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 member is manufactured by making full use of machining such as cutting and turning and plastic working such as forging. However, in recent years, it is possible to improve production efficiency and yield. In many cases, plastic working is often used.

  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 tracks having one end opened and extending axially on an inner diameter surface. A method for manufacturing an outer joint member integrally including a cup portion provided with a groove and a shaft portion extending axially outward from the other end of the cup portion through various forging processes is described. Specifically, a forging process in which a rod-shaped material is formed into an intermediate forged product having a cup-shaped portion having a track groove roughly formed on the inner diameter surface by 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 (final shape) by subjecting the cup-shaped portion to ironing.

JP 2002-213476 A

  By the way, the shape (size of each part) of the final forged product is likely to vary among individuals due to the variation in the weight and volume between the rod-shaped materials supplied to the pre-forging process, and among them the opening of the cup-shaped part The end portion is a portion where variation is particularly likely to appear. Therefore, before paying out the final forged product to a subsequent process such as a finishing process for turning or grinding, or a heat treatment process for quenching, the open end of the cup-shaped part of the final forged product It is inspected whether or not the portion is molded into a predetermined shape (whether or not the depth dimension of the cup-shaped portion is within the tolerance range), and only acceptable products are paid out to the subsequent process.

  The shape of the open end of the cup-shaped part in the intermediate forged product or the final forged product is not only the weight and volume of the rod-shaped material, but also the intermediate product obtained in the intermediate stage of the pre-forging process (the product that will eventually become the intermediate forged product) ) Also depends on the molding accuracy. Therefore, it is easy to determine and confirm whether or not the intermediate product or intermediate forged product has been formed into a predetermined shape, more specifically, whether or not the workpiece has been appropriately plastically deformed following the forging die used in the pre-forging process. If this is possible, the complicated inspection process can be simplified or omitted, and it is not necessary to bother the intermediate forging product, which is likely to be defective after the ironing process. Can be improved.

  However, the pre-forging process for obtaining an intermediate forged product is generally performed continuously using a forging device (transfer press) in which a plurality of forging dies are continuously arranged along the feed direction. is there. Therefore, when trying to determine and confirm whether or not the product has been molded into a predetermined shape on the way, that is, whether or not the workpiece has been appropriately plastically deformed following the forging die, the forging device is completely stopped and sampling inspection is performed. Need to run. However, this significantly reduces the productivity of the outer joint member. In addition, if the halfway product that has been extracted from the forging device is returned to the forging device again, it will be difficult to obtain accuracy. Therefore, even if the intermediate product that has been extracted is an acceptable product, it cannot be returned to the forging device again. . For this reason, even if the halfway product extracted from the forging device is an acceptable product, the halfway product must be discarded, resulting in a decrease in product yield.

  In view of such a situation, the present invention is a component of a constant velocity universal joint, and in the middle of manufacturing an outer joint member having a cup portion having a track groove on an inner diameter surface, It is possible to easily and accurately determine whether or not the opening end of the cup-shaped part has been molded into a predetermined shape, thereby contributing to the improvement of productivity and product yield of the outer joint member and, consequently, the constant velocity universal joint. With the goal.

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. Before producing 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, using a forging device in which a plurality of forging dies are provided continuously, Including a forging process and an ironing process for obtaining a final forged product by ironing the cup-shaped portion of the intermediate forging product. The pre-forging process is performed by using a closed forging die having a die and a punch. A step of obtaining a halfway product having an upset portion by staking processing and a step of obtaining an intermediate forged product by subjecting the upset portion to backward extrusion , and in the step of obtaining a halfway product , a closed forging die of At least punch provided a mold unit Chi, in part at least to an intermediate forging cup portion open end face of one of the swaging unit, the acceptance of the open end portion shape of the cup-shaped portion of the intermediate forgings visually determinable The mark part is formed by molding.

  In this way, after the end of the pre-forging process, the opening end of the cup-shaped part is predetermined by checking whether or not the mark part of the predetermined form is molded in the cup-shaped part of the intermediate forged product. It can be determined whether or not it has been formed into a shape (whether or not the workpiece has been appropriately plastically deformed following a plurality of forging dies). In particular, since the above-described mark portion is molded on the intermediate product that will eventually become an intermediate forged product, the mark portion is molded by the mold portion provided in the forging die that is likely to cause poor molding accuracy. By doing so, it becomes possible to easily review the molding conditions in the forging process. Therefore, in the pre-forging process, it is not necessary to stop the forging device completely and perform sampling inspection, and it is possible to eliminate the trouble of ironing the intermediate forged product that is likely to be defective after ironing. It becomes. From these things, it can avoid as much as possible that the productivity of an outer joint member and the problem of a product yield fall arise.

  The above configuration is preferably applied when the forging device has a closed forging die, that is, when the pre-forging step is performed using a forging device in which at least one of the plurality of forging dies is constituted by a closed forging die. be able to. The closed forging die referred to here is a forging die configured to perform forging in a state where the entire workpiece is sealed in the die. According to the verification by the inventors of the present application, in the forging process stage using the hermetic forging die, a molding accuracy defect due to insufficient satisfaction is particularly likely to occur. Therefore, if the mark part is molded at the forging process stage of the intermediate product by the closed forging die in the pre-forging process, the degree of material satisfaction at this forging process stage is properly grasped, and the outer joint member This is advantageous for improving productivity and product yield.

  It is desirable that the mark part is molded in a portion that is easy to visually check in the cup-shaped part. Specifically, an end face mark portion as a mark portion can be molded at a site that becomes an open end face (end face on the opening side) of the cup-shaped portion of the intermediate forged product in the intermediate product. The form of the end face mark portion is not particularly limited, and for example, a plurality of shapes may be formed radially, an infinite number of dots may be formed, or an annular shape (one or more) may be formed. In addition, in the intermediate product, in place of the portion that becomes the opening end surface of the cup-shaped portion of the intermediate forging product, or in addition to the portion that becomes the opening end surface, the mark portion on the portion that becomes the outer diameter surface of the cup-shaped portion of the intermediate forging product The outer diameter mark portion may be molded. Further, these mark portions (end face mark portions and outer diameter mark portions) may be formed in a concave shape or may be formed in a convex shape. Whatever form of mark portion is molded, it is desirable that the mark portion has a form that does not adversely affect the operability and the like in consideration of the case where the mark portion remains in the final product.

  Further, the present invention created to achieve the above object is for a constant velocity universal joint having a cup portion having one end opened, and a plurality of track grooves extending in the axial direction on the inner diameter surface of the cup portion. An outer joint member, in which the cup part is formed by forging, and a part or all of the track groove is formed into a finished shape by ironing after pre-forging, at the opening end of the cup part, A mark portion capable of visually determining whether the opening end shape is acceptable is provided by molding with a forging die.

  If it is an outer joint member which has such a structure, there can exist an effect similar to the case where the manufacturing method of the outer joint member which concerns on above-described this invention is employ | adopted.

  In the outer joint member having the above configuration, the mark portion can be provided on the opening side end surface of the cup portion, the outer diameter surface of the cup portion, or both.

The present invention can also be preferably applied to an outer joint member that integrally has a shaft portion that extends axially outward from the other end of the cup portion.

  The present invention can be applied to an outer joint member in which a track groove is composed of only a straight portion, that is, an outer joint member for a sliding type constant velocity universal joint. Examples of applicable sliding constant velocity universal joints include tripod type constant velocity universal joints (TJ) and double offset type constant velocity universal joints (DOJ). In this case, the entire track groove (entire area) can be finished by ironing. Further, according to the present invention, the track groove is positioned relatively on the linear portion located on one end side (opening end portion side) of the cup portion, and relatively on the other end side (non-opening end portion side) of the cup portion. It can also be applied to an outer joint member for an undercut-free type constant velocity universal joint (UJ) which is a kind of a fixed type constant velocity universal joint. In this case, at least a linear portion of the track groove can be finished by ironing.

  Moreover, a constant velocity universal joint can be comprised by the outer joint member which concerns on this invention described above, and the joint internal components accommodated in the cup part inner periphery.

  As described above, according to the present invention, during the manufacture of an outer joint member that is a component of a constant velocity universal joint and has a cup portion having a track groove on the inner diameter surface, an intermediate forged product is produced. It is possible to easily and accurately determine whether or not the opening end of the cup-shaped portion is molded into a predetermined shape. As a result, the productivity and product yield of the outer joint member, and thus the constant velocity universal joint, can be improved.

(A) A figure is a front view of the outside joint member for constant velocity universal joints concerning one embodiment of the present invention, and (b) figure is a sectional view taken along the line XX in (a) figure. (A)-(c) figure is a schematic sectional drawing of the intermediate product obtained by each forging process of a pre-forging process, (d) figure is a schematic sectional drawing of an intermediate forging product. (A) The figure is a schematic sectional view showing the initial state of the forging process by the third forging die in the pre-forging step, (b) is a plan view of the punch shown in FIG. (C) is a schematic sectional drawing which shows the intermediate state of the forge process by a 3rd forge metal mold | die. It is sectional drawing which shows a ironing process typically. (A) The figure is a front view of a third intermediate product molded into a predetermined shape, (b) is a schematic cross-sectional view taken along line XX in (a), and (c) is (a). The front view of the 4th intermediate product obtained by performing back extrusion processing to the 3rd intermediate product shown in (d) is a schematic sectional view taken along the line XX in FIG. (A) The figure is a front view of a third intermediate product that has not been formed into a predetermined shape, (b) is a schematic cross-sectional view taken along line XX in (a), and (c) is (a). The front view of the 4th intermediate product obtained by giving back extrusion processing to the 3rd intermediate product shown in a figure, (d) figure is a schematic sectional view seen from the XX line in (c) figure. . (A) The figure is a front view of a third intermediate product according to another embodiment, (b) The figure is a schematic sectional view taken along the line XX in (a), and (c) The figure is another embodiment. The front view of the 3rd intermediate product which concerns on this, (d) The figure is a schematic sectional drawing seen from the XX line in (c) figure. (A) A figure is a front view of the 3rd halfway product concerning other embodiments, and (b) figure is a schematic sectional view taken along a line XX in (a) figure. (A)-(e) figure is a front view of the 3rd halfway product concerning other embodiments.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, for the sake of convenience, one embodiment of the outer joint member according to the present invention will be described first with reference to FIG. 1, and then one embodiment of the method for manufacturing the outer joint member according to the present invention will be described with reference to FIGS. 4 will be described.

  FIG. 1A shows a schematic front view of an outer joint member 1 for a constant velocity universal joint according to an embodiment of the present invention (hereinafter, simply referred to as “outer joint member 1”), which is the same as FIG. 1 is a schematic cross-sectional view of the outer joint member 1 (a cross-sectional view taken along line XX in FIG. 1A). This outer joint member 1 is an outer joint member for a tripod type constant velocity universal joint (TJ) which is a kind of sliding type constant velocity universal joint that allows both angular displacement and axial displacement, and one end is open. The bottomed cylindrical cup portion 2 and the shaft portion 3 extending axially outward from the other end of the cup portion 2 are integrally provided. The tripod type constant velocity universal joint is configured by incorporating a tripod member as an inner joint member, a roller as a torque transmission member, or the like on the inner periphery of the cup portion 2 of the outer joint member 1.

  Three track grooves 5 extending in the axial direction are formed at equal positions in the circumferential direction of the inner diameter surface 4 of the cup portion 2. Each track groove 5 has a pair of roller guide surfaces 6 and 6 which face each other in the circumferential direction, and is formed in a straight line including the roller guide surfaces 6 and 6 and extending in parallel with the joint axis. The cross section perpendicular to the axis of the cup portion 2 is a flower crown formed by alternately arranging three large diameter portions and small diameter portions in the circumferential direction, and a track groove 5 is formed on the inner periphery of each large diameter portion. Has been. Although not shown in FIG. 1, in an actual product, an inlet chamfer for allowing angular displacement of the joint is provided in the region between the track grooves 5 and 5 on the inner peripheral edge of the opening of the cup portion 2, Further, an annular groove for fitting one end of the boot is provided at a predetermined position in the axial direction of the outer diameter surface 8 of the cup portion 2.

  As will be described in detail later, the outer joint member 1 is formed from a rod-shaped material using a forging device in which a plurality of forging dies are continuously provided along the feed direction, as shown in FIG. By performing a forging process before obtaining an intermediate forged product 1 ″ having a cup-shaped portion 2 ″ having a track groove 5 ′ roughly formed on the surface, and by performing ironing on the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ An ironing step of obtaining a final forged product 1 ′ (see a two-dot chain line in FIG. 4) having a cup-shaped portion 2 ′ in which a groove 5 is formed into a finished shape (here, the final shape), and a final forged product 1 ′ After passing through a finishing process for finishing each part into a finished product shape, it is completed by heat treatment.

  As described above, in the cup portion 2, the track groove 5 (the groove bottom surface of the track groove 5 and the pair of roller guide surfaces 6 and 6) is entirely cup-shaped in the intermediate forged product 1 ″ shown in FIG. Part 2 ″ is formed into a finished shape by ironing. On the other hand, the opening end surface 7 of the cup-shaped portion 2 ″ shown in FIG. 1 is free to deform as the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ is ironed. 4 (see FIG. 4), and not a surface finished by machining such as turning, etc. Therefore, although not shown, the opening end surface 7 of the cup portion 2 has some undulation. .

  In the cup part 2, the shape of the opening end part is acceptable (the opening end part of the cup part 2 is free from sagging due to unsatisfaction with the forging die / the cup depth extends over the entire circumference of the cup part 2. A mark portion is provided for enabling visual determination of whether or not the tolerance is within the tolerance range. Here, a plurality of end face mark portions 11 serving as mark portions are provided on the opening end surface 7 of the cup portion 2 at predetermined intervals in the circumferential direction, and an outer diameter mark portion serving as a mark portion is provided in the opening side region of the outer diameter surface 8 of the cup portion 2. A plurality of 12 are provided at predetermined intervals in the circumferential direction. Each end face mark portion 11 is formed in a groove shape extending radially, and each outer diameter mark portion 12 is formed in a groove shape extending in the axial direction. And since these end surface mark part 11 and the outer-diameter mark part 12 are formed in the predetermined aspect, the said outer joint member 1 is the sagging resulting from the unsatisfactory to a forge metal mold | die at the opening edge part of the cup part 2. FIG. And determining that the open end portion of the cup portion 2 is an acceptable product formed in a predetermined shape over the entire circumference (the cup depth is within the tolerance range over the entire circumference of the cup portion 2). Can do.

  More specifically, as shown in FIGS. 6 (a) and 6 (b), the outer peripheral edge portion of the third intermediate product M3, which finally becomes the intermediate forged product 1 "and eventually the final forged product 1 ', 3 may occur due to unsatisfaction of the work (second intermediate product M2) on the third forging die for forming the intermediate product M3 in FIG. As shown in d), the opening end portion (outer peripheral edge portion) of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ obtained by subjecting the third intermediate product M3 to forging processing (rear extrusion processing) is left as it is. However, in many cases, it is difficult to determine whether or not this sagging is within an allowable range by visual observation, whereas the end face mark portion 11 and the outer diameter mark portion 12 as the mark portions are molded. As a result, the occurrence of sagging in the middle of the pre-forging process, and this The presence or absence of shape inaccuracies that cause can be determined accurately.

  The end face mark portion 11 and the outer diameter mark portion 12 are molded at an intermediate stage of the pre-forging process (in this embodiment, an upsetting process stage using the third forging die 30 shown in FIG. 3). Therefore, the depth dimension of the end face mark portion 11 and the outer diameter mark portion 12 provided on the cup portion 2 of the outer joint member 1 is formed by various processes performed after the both mark portions 11 and 12 are molded. In many cases, it is different from the depth dimension of the mark portions 11 and 12 immediately after the mark.

  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 is a pre-forging step for obtaining the intermediate forged product 1 ″ shown in FIG. 2 (d), and the ironing for obtaining the final forged product 1 ′ shown by a two-dot chain line in FIG. It is completed through a process, a finishing process for finishing each part of the final forged product 1 ′ into a finished product shape, and a heat treatment process for heat-treating the final forged product 1 ′ finished into a finished product shape.

  In the pre-forging process, the feed direction of the rod-shaped material and intermediate product (molded product formed by subjecting the rod-shaped material to one or a plurality of forging processes and finally the intermediate forged product 1 ″) is sent downstream. A plurality of forging dies (in this embodiment, four forging dies. Hereinafter, the first, second, third, and fourth forging dies are sequentially provided from the upstream side) 1. Two forging devices are used to obtain an intermediate forged product 1 ″ having a cup-shaped portion 2 ″ shown in FIG. 2 (d) from a rod-shaped material (not shown). The forging process uses a so-called transfer press equipped with a (1) forging device in which the first to fourth forging dies are continuously provided, a transfer means for sequentially transferring rod-shaped materials and intermediate products to the downstream side, etc. And is executed automatically.

  In the pre-forging process, first, a rod-shaped material (not shown) is put into a forging device, and the rod-shaped material is subjected to upsetting by a first forging die, as shown in FIG. A first intermediate product M1 having a rounded peripheral edge is formed. Next, the first intermediate product M1 is transferred and put into the second forging die, and the first intermediate product M1 is subjected to forward extrusion processing with the second forging die, as shown in FIG. 2 (b). A shaft portion 3 ′ having a relatively large diameter on one end side and a relatively small diameter shaft portion 3 ′ (finally finished to the shaft portion 3) on the other end side (side on which the outer peripheral edge portion is rounded). A second intermediate product M2 having a portion to be obtained).

  Next, the second intermediate product M2 is transferred and charged into the third forging die 30 shown in FIG. The third forging die 30 is a so-called closed forging die. That is, as shown in FIGS. 3A and 3C, the third forging die 30 includes a punch 31 and a die 32 that relatively move toward and away from each other, and both of them move relatively closer. Sometimes, a sealed molding space is defined between the two. Then, when the large diameter portion of the second intermediate product M2 is subjected to upsetting with the third forging die 30, and the large diameter portion is compressed and deformed in the axial direction and expanded and deformed in the radial direction, FIG. And as shown in FIG.3 (c), the 3rd intermediate product M3 which has the upsetting part 22 is obtained.

  Although details will be described later, the third intermediate product M3 is a fourth forging die that is disposed adjacent to the downstream side of the third forging die 30 and has a cup-shaped portion 2 ″ shown in FIG. It is formed into a forged product 1 ″. Further, in the third intermediate product M3, there are intermediate portions on the opening end surface and the outer diameter surface (end surface and outer diameter surface of the upsetting portion 22) of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″, respectively. A plurality of concave groove-shaped end face mark portions 11 and outer diameter mark portions 12 are formed at predetermined intervals in the circumferential direction as mark portions that enable the visual determination of whether or not the opening end shape of the cup-shaped portion 2 ″ of the forged product 1 ″ is acceptable. ing. The arrangement form of the end face mark part 11 and the outer diameter mark part 12 formed in the upsetting part 22 is the same as the arrangement form of the both mark parts 11 and 12 existing in the cup part 2 shown in FIGS. It is.

  The end face mark portion 11 and the outer diameter mark portion 12 are provided on the lower end surface 31 a of the punch 31 and the inner wall surface 32 a of the die 32 at the same time as the punch 31 and the die 32 are moved toward and away from each other to form the upsetting portion 22. Molding is performed by the formed convex mold parts 31b and 32b. Specifically, as shown in FIG. 3A, the second intermediate product M <b> 2 is arranged on the inner periphery of the die 32, and then the punch 31 is moved relatively closer to the die 32, thereby The large diameter portion of the second intermediate product M2 is compressed and deformed in the axial direction and expanded and deformed (see FIG. 3C), and the large diameter portion of the second intermediate product M2 is formed on the lower end surface 31a of the punch 31 and the die 32. Plastic deformation is performed along the inner wall surface 32a. As a result, the third intermediate product M3 having the upsetting portion 22 is molded, and at the same time, the end face marking portion 11 and the outer diameter marking portion 12 are molded on the end surface and the outer diameter surface of the upsetting portion 22, respectively. The

  In addition, as shown in FIG. 3B, a plurality of convex mold parts 31b (12 in the illustrated example) are provided on the lower end surface 31a of the punch 31 used in the present embodiment at predetermined intervals in the circumferential direction. In addition, each mold part 31b extends radially from the outer diameter end of the lower end surface 31a of the punch 31 toward the inner diameter side. Although the height dimension of the shaping | molding die part 31b is suitably changed according to the size etc. of the outer joint member 1, it is set in the range of 0.1 mm-5.0 mm, for example. Although not shown in detail, a plurality of convex mold parts 32 b provided on the inner wall surface 32 a of the die 32 are provided at the same pitch as the mold parts 31 b of the punch 31. Although the height dimension of the shaping | molding die part 32b is suitably changed according to the size etc. of the outer joint member 1, it is in the range of 0.1 mm-5.0 mm like the shaping | molding die part 31b provided in the punch 31, for example. Set to

  After transferring the third intermediate product M3 formed as described above to the fourth forging die, the rear forging process is performed on the upset portion 22 of the third intermediate product M3 with the fourth forging die. By applying, an intermediate forged product 1 ″ having a cup-shaped portion 2 ″ is obtained as shown in FIG. As the upsetting portion 22 is formed into a cup shape by the backward extrusion process, the inner diameter side portion of each end face mark portion 11 disappears.

  The cup-shaped portion 2 ″ of the intermediate forged product 1 ″ has a shape similar to the cup portion 2 of the outer joint member 1 as a finished product. That is, the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ has a corollary cross-sectional shape, and three track grooves 5 ′ having roller guide surfaces 6 ′ and 6 ′ are provided at circumferentially equal positions on the inner diameter surface. Roughly molded. The cup-shaped portion 2 ″ of the intermediate forged product 1 ″ is thicker than the cup portion 2 of the outer joint member 1 shown in FIG. 1 and is shorter in the axial direction. Therefore, the axial dimension of the track groove 5 ′ provided on the inner diameter surface of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ is the axis of the track groove 5 provided on the inner diameter surface 4 of the cup portion 2 of the outer joint member 1. It is shorter than the directional dimension.

  The intermediate forged product 1 ″ obtained as described above is transferred to the ironing process. In the ironing process, the outer peripheral portion corresponds to the shape of the inner diameter surface 4 of the cup portion 2 shown in FIG. Using the molding die provided with the ironing punch 41 and the ironing die 42 whose inner diameter corresponds to the shape of the outer diameter surface 8 of the cup part 2, the cup-shaped part 2 "of the intermediate forged product 1" is ironed. As shown by the two-dot chain line in the figure, a final forged product 1 ′ having a cup-shaped portion 2 ′ in which the track groove 5 is formed into a finished shape is obtained.

  The final forged product 1 ′ is transferred to the finishing process. In the finishing process, it is difficult to form by the various forging processes described above (for example, an annular groove for boot fitting to be provided on the outer diameter surface of the cup part 2 or a free end outer diameter of the shaft part 3). Spline etc.) is formed by machining such as grinding, and the final forged product 1 'is finished into a finished product shape. And the outer joint member 1 shown to FIG. 1 (a) (b) is completed by giving heat processing, such as hardening, to the final forging product 1 'finished in the shape of the finished product as a whole.

  As described above, in the present invention, in the pre-forging process, the intermediate product (the third intermediate product M3 in the present embodiment) that finally becomes the intermediate forged product 1 ″ is formed at the same time as the forming. The mold 31b, 32b provided on the punch 31 and the die 32 constituting the forging die (third forging die 30) is used to place the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ on the third intermediate product M3. The end face mark portion 11 and the outer diameter mark portion 12 as the mark portions that enable the visual determination of whether or not the opening end shape is acceptable are molded. In this way, after the pre-forging process is completed, the intermediate forged product 1 ″ It is confirmed whether or not the opening end of the cup-shaped part 2 ″ is molded into a predetermined shape by checking whether or not the mark parts 11 and 12 of the predetermined mode are molded in the cup-shaped part 2 ″. The second intermediate product M2 follows the third forging die 30. Earnestly it can determine whether the plastic deformation (unsatisfied whether arising in the second middle products M2 to the third forging dies 30).

  Specifically, as shown in FIGS. 5 (a) and 5 (b), the mold 31b of the punch 31 and the mold 32b of the die 32 shown in FIG. If the third halfway product M3 in which the end face mark portion 11 and the outer diameter mark portion 12 accurately following the shape are molded is obtained, the fourth forging die is pushed backward with respect to the third halfway product M3. When the intermediate forged product 1 ″ having the cup-shaped portion 2 ″ is obtained by processing, the opening end face and the outer diameter surface of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ are shown in FIG. As shown in d), the end face mark portion 11 (the outer diameter portion thereof) and the outer diameter mark portion 12 remain as they are. Therefore, if the end face mark portion 11 and the outer diameter mark portion 12 having a predetermined shape remain in the cup-shaped portion 2 ″ of the intermediate forged product 1 ″, the intermediate forged product 1 ″ has the cup-shaped portion 2 ″ having a predetermined shape. It can be easily determined that it is a molded acceptable product.

  On the other hand, as shown in FIGS. 6 (a) and 6 (b), end face mark portions 11 and outer diameter mark portions 12 having predetermined shapes are formed in a partial region in the circumferential direction of the end surface and the outer diameter surface of the upsetting portion 22. When the third halfway product M3 that has not been molded is obtained, when the third halfway product M3 is subjected to a backward extrusion process, as shown in FIGS. 6C and 6D, a cup shape is obtained. An intermediate forged product 1 ″ is obtained in which the end face mark portion 11 and the outer diameter mark portion 12 having a predetermined shape are not provided in a partial region in the circumferential direction of the portion 2 ″. As described above, if the end face mark portion 11 and the outer diameter mark portion 12 having a predetermined shape are not present in the entire region of the cup-shaped portion 2 ″, the intermediate forged product 1 ″ is a product on its way (second way mark). It can be easily determined that the product M2) does not accurately follow the third forging die 30 and the cup-shaped portion 2 ″ is a rejected product that has not been formed into a predetermined shape.

  From the above, if the manufacturing method according to the present invention is adopted, in the pre-forging process, it is not necessary to completely stop the forging device and perform sampling inspection, and it is highly possible that the product will be defective after ironing. Therefore, it is possible to save the trouble of ironing the forged product 1 ″. Therefore, it is possible to avoid as much as possible the problems of lowering the productivity of the outer joint member 1 and the product yield, and the outer joint member 1. In particular, in the present embodiment, the intermediate forged product 1 ″ is formed of a closed forging die that is likely to cause poor forming accuracy. The mark portions 11 and 12 were molded at the forging stage using the third forging die 30. Therefore, it is particularly advantageous in improving the productivity of the outer joint member and the product yield.

  The outer joint member 1 and the manufacturing method thereof according to one embodiment of the present invention have been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. It is possible to make changes.

  For example, as shown in FIGS. 7A and 7B, the mark portion of the third intermediate product M3 is the upsetting portion 22 that is a portion that becomes the end surface of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″. 7 (c) (d), the outer diameter surface of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ of the third intermediate product M3, as shown in FIGS. Alternatively, the molding may be performed only on the outer diameter surface of the upsetting portion 22 which is a portion to be formed.

  In addition, as described above, the present invention is not only for obtaining the third intermediate product M3 in which the end surface of the upsetting portion 22 forms a flat surface, but also as shown in FIGS. 8 (a) and 8 (b). Further, the present invention can be preferably applied to the case where the third intermediate product M3 having the upsetting portion 22 provided with the recessed portion 22a in the center of the end surface is obtained.

  Further, the form of the end face mark portion 11 to be molded on the end face of the third intermediate product M3 (the upsetting portion 22) is not limited to that described above. For example, the end face mark portion 11 may be formed in a radial shape so as to cross the end face of the upsetting portion 22 as shown in FIG. 9A, or as shown in FIGS. 9B and 9C. One or a plurality of rings may be formed in a ring shape. Further, as shown in FIGS. 9D and 9E, the end face mark portion 11 may be formed innumerably in a dotted shape. In short, the end face mark portion 11 and / or the outer diameter mark portion 12 is an intermediate forging to determine whether or not a molding accuracy failure has occurred in the upsetting portion 22 in a region where a molding accuracy failure (insufficient mold filling) is likely to occur. The shape is not particularly limited as long as it can be easily judged at the stage when the product 1 ″ is obtained. Therefore, either one or both of the end face mark portion 11 and the outer diameter mark portion 12 are concave. It may be molded or may be molded into a convex shape.

  In addition, in the above, when the intermediate forged product 1 ″ of the outer joint member 1 is obtained through four steps (using a forging device in which four forging dies are continuously provided), the third is a closed forging die. At the same time as the third intermediate product M3 is formed using the forging die 30, the end face mark portion as a mark portion is formed by the mold portions 31b and 32b provided on the punch 31 and the die 32 of the third forging die 30. 11 and the outer diameter mark portion 12 are molded, but the mark portion may be molded at another stage (for example, a stage when the second intermediate product M2 is molded). The case where the present invention is applied when the intermediate forged product 1 ″ of the outer joint member 1 is obtained through four steps has been described, but the intermediate forged product 1 ″ is obtained by obtaining three or less steps or five or more steps. In addition, the present invention can be preferably applied.

  Further, in the above, the outer joint member 1 shown in FIG. 1, that is, the opening end surface 7 of the cup portion 2 is obtained by the free deformation of the cup-shaped portion 2 ″ of the intermediate forged product 1 ″ accompanying the ironing process. In the manufacturing of the outer joint member 1, the case where the manufacturing method according to the present invention is applied has been described, but the outer joint member 1 in which the opening end surface 7 of the cup portion 2 is finished by machining such as turning is manufactured. In this case, the present invention can be preferably applied. However, in this case, the end face mark portion 11 and / or the outer diameter mark portion 12 basically does not exist in the cup portion 2 of the outer joint member 1.

  In the above, the outer joint member 1 for a tripod type constant velocity universal joint (TJ), which is a kind of sliding type constant velocity universal joint, and the case where the present invention is applied when manufacturing the outer joint member 1 are described. However, the present invention can also be applied to the manufacture of other sliding type constant velocity universal joints, such as an outer joint member for a double offset type constant velocity universal joint (DOJ), and this outer joint member. Is possible.

  The present invention is not limited to the outer joint member for the sliding type constant velocity universal joint described above, but also the outer joint member for the fixed type constant velocity universal joint such as an undercut free type constant velocity universal joint (UJ). And when the outer joint member is manufactured. The fixed type constant velocity universal joint does not allow axial displacement but allows only angular displacement, and the track groove of the outer joint member incorporated therein is relatively positioned on the cup opening side. It is comprised by the linear part extended in parallel with a joint axis line, and the circular arc-shaped part located in a cup bottom side relatively.

DESCRIPTION OF SYMBOLS 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 11 End face mark part (mark part)
12 Marking part of outer diameter (marking part)
30 Third forging die (sealed forging die)
31 Punch 31b Mold part 32 Dies 32b Mold part M1 First intermediate product M2 Second intermediate product M3 Third intermediate product

Claims (5)

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,
Using a forging device in which a plurality of forging dies are continuously provided, a pre-forging step for obtaining an intermediate forged product having a cup-shaped portion in which the track groove is roughly formed on an inner diameter surface from a rod-shaped material; and the intermediate forging An ironing process for obtaining a final forged product by ironing the cup-shaped portion of the product, and the pre-forging process is upset by an upsetting process performed using a closed forging die having a die and a punch. A step of obtaining an intermediate product having a portion, and a step of obtaining the intermediate forged product by subjecting the upsetting portion to backward extrusion,
In the step of obtaining the intermediate product, at least a part of the closed forging die that is an opening end surface of the cup-shaped portion of the intermediate forged product, at least in the mold portion provided in the punch , A method for producing an outer joint member for a constant velocity universal joint, characterized in that a mark portion that enables visual determination as to whether or not the shape of the open end portion of the cup-shaped portion of the intermediate forged product can be visually determined. The method for manufacturing an outer joint member for a constant velocity universal joint according to claim 1 , wherein a plurality of the mark portions are radially formed. The method for manufacturing an outer joint member for a constant velocity universal joint according to claim 1 , wherein the mark part is formed innumerably in a dotted shape. Method of manufacturing a constant velocity universal joint for the outer joint member according to claim 1 for forming the mark portion annularly. In the step of obtaining the middle product, of the upsetting part, further wherein the portion to be the outer surface of the cup-shaped portion of the intermediate forgings, any one of claims 1-4 for molding the mark portion The manufacturing method of the outer joint member for constant velocity universal joints of description.

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