JP2014228057A - Manufacturing method of outside joint member for constant velocity universal joint, intermediate forged product processed to outside joint member, and final forged product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To manufacture a high-quality outside joint member at a low cost.SOLUTION: A manufacturing method of an outside joint member 1 includes: a pre-forging step for molding a rod-shaped raw material M into an intermediate forged product 21 having a cup-shaped part 22 in which track grooves are roughly formed at an inside diameter face after sequentially molding the rod-shaped raw material M into first to third middle products M1 to M3 by performing, for example, four times of forging processing stepwise; and a grueling step for molding the intermediate forged product into a final forged product having track grooves 5 of finished shapes. The third middle product M3 manufactured in the pre-forging step has, at its one end face M3a, an endless third mark M3b formed by the deformation of the rod-shaped raw material M to a one-end external edge Mb, and the third mark M3b is wholly arranged outside in a radial direction rather than a pressurized region of the one end face M3a formed by a molding punch 32 of the cup-shaped part 22.

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 bottomed cylindrical cup portion that is open at one end, and a plurality of track grooves are provided on the inner diameter surface of the cup portion. An outer joint member and joint inner parts such as an inner joint member and a torque transmission member housed in 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 often manufactured using plastic working as much as possible in order to improve production efficiency and yield.

  As an example, Patent Document 1 below is an outer joint member of a tripod type constant velocity universal joint which is a kind of sliding type constant velocity universal joint, and a plurality of track grooves extending in the axial direction are provided on an inner diameter surface. In addition, there is described a method for manufacturing a product having a bottomed cylindrical cup part and a shaft part extending in the axial direction from the bottom part of the cup part through various forging processes. Specifically, by performing various forging processes such as upsetting and extrusion step by step, the bar-shaped material is an intermediate forged product having a cup-shaped portion having a track groove roughly formed on the inner diameter surface (in Patent Document 1). The outer side including a pre-forging step for forming into a “fourth intermediate material” and an ironing step for obtaining a final forging product having a finished track groove on the inner diameter surface by ironing the intermediate forging product. It is a manufacturing method of a joint member. In more detail about the pre-forging process, the rod-shaped material is formed into a columnar material by upsetting, and the columnar material is formed into a second intermediate material having a large diameter portion and a small diameter portion by extrusion (forward extrusion). The second intermediate material is formed into a third intermediate material by upsetting, and the third intermediate material is an intermediate forged product integrally having a bottomed cylindrical cup-shaped portion and a shaft-shaped portion by extrusion (rear extrusion). To be molded.

JP 2002-213476 A

  The above rod-shaped material is generally obtained by cutting a long bar material to a predetermined size with a saw blade or by shearing to a predetermined size with a press die. 12, protrusions (burrs and edges) 102 may be intermittently or continuously generated on the outer peripheral edge (one end and the other outer peripheral edge) 101 of the rod-shaped material 100. Further, in the case where the rod-shaped material 100 is produced at a place different from the manufacturing process of the outer joint member and is transported to the manufacturing process of the outer joint member, there is a collision between the rod-shaped materials 100 during transportation. In some cases, the protrusion 102 may be generated on the outer peripheral edge 101 of the rod-shaped material 100.

  When the rod-shaped material 100 is put into the pre-forging process as it is and forging is sequentially performed in the manner described in Patent Document 1, the protrusion 102 enters the inner diameter surface of the cup-shaped portion (the inner diameter surface of the cup-shaped portion). There is a high possibility that an intermediate forged product (with unwanted irregularities formed) is produced. The protrusions 102 (unevenness) that have entered the inner diameter surface of the cup-shaped portion can be removed by machining such as turning, grinding, polishing, etc., but in this case, the shape required for each cup portion of the outer joint member And there is a risk that the thickness cannot be secured. Therefore, the intermediate forged product in which the protrusion 102 enters the inner diameter surface of the cup-shaped portion is inevitably discarded. As a result, the product yield is reduced, and the outer joint member is obtained by plastic processing. The cost merit cannot be fully enjoyed.

  The above problems can be solved as much as possible by smoothing the outer peripheral edge of the rod-shaped material by machining or the like before the rod-shaped material is put into the pre-forging process. However, in this case, (1) the manufacturing cost increases because the number of steps increases, and (2) an intermediate forged product having a predetermined shape, and thus an outer joint member, can be obtained because the volume of the rod-shaped material is reduced. Invite new problems such as disappearance.

  In view of such circumstances, an object of the present invention is to make it possible to manufacture a high-quality outer joint member at low cost.

  In order to solve the above-mentioned problems, the present invention has a bottomed cylindrical cup portion having an open end, and a constant velocity in which a plurality of track grooves extending in the axial direction are provided on the inner diameter surface of the cup portion. A method of manufacturing an outer joint member for a universal joint, wherein a plurality of forging processes are executed step by step, whereby a rod-shaped material is sequentially turned into first to Nth intermediate products (N is a positive integer of 2 or more). A pre-forging process in which the inner forged step is formed into an intermediate forged product having a bottomed cylindrical cup-shaped portion having a track groove roughly formed on the inner diameter surface, and a final forged product having a finished-shaped track groove. An N-th intermediate product produced in the middle of the pre-forging process, and having an endless trace formed by deforming the outer peripheral edge of one end of the rod-shaped material. And the whole of this trace part is the forging die used in the pre-forging process. Characterized in that by the forming punch of the cup-shaped portion and that is disposed radially outward than the pressurized area of the end face.

  In this way, even if a rod-shaped material having a protrusion such as a burr along its outer peripheral edge is used as the rod-shaped material, the intermediate forged product in which the protrusion enters the inner diameter surface of the cup-shaped part, and thus the cup As a result, it is possible to prevent as much as possible the production of a final forged product in which the projections enter the inner diameter surface (particularly, the track groove forming region). Furthermore, if it says as mentioned above, the said processus | protrusion can obtain the intermediate forging product which exists in the opening end surface of a cup-shaped part, by extension, the final forging product which exists in the opening end surface of a cup part, and also an outer joint member. it can. And since the opening end surface of the cup portion of the outer joint member is not a surface to which other members are attached or the other members are in contact, even if the protrusion is present in the opening end surface of the cup portion, The joint performance is not adversely affected. Therefore, it is not necessary to carry out a finishing process to remove the protrusions generated at the outer peripheral edge of one end of the rod-shaped material, and as a rod-shaped material, a long rod cut to a predetermined size or sheared is used as it is. Can do. Therefore, a high quality outer joint member capable of exhibiting desired joint performance can be manufactured at low cost.

  According to said manufacturing method, as above-mentioned, the rod-shaped raw material which cut | disconnected or sheared the elongate bar to the predetermined dimension can be used as it is.

  The N-th intermediate product is, for example, a forging process executed in the first stage of the pre-forging process, and the first intermediate in which a portion that becomes the above-described trace portion is provided on an end surface that is one end surface of the N-th intermediate product. In at least one forging process performed after obtaining the product and then obtaining the N-th intermediate product, an end surface serving as one end surface of the N-th intermediate product among the workpieces, and provided on this end surface It can be obtained by expanding the diameter of the portion that becomes the trace portion. The “work material” here is a first to (N-1) th intermediate product.

  Among the forging processes for obtaining the 1st to Nth intermediate products, any one of the forging processes, of the workpiece, the end surface which is the one end surface of the Nth intermediate product has a mortar shape, You may make it shape | mold the recessed part in which the site | part used as the said trace part was provided in the wall surface. The term “mortar-shaped recess” as used herein means a recess that has a cross-sectional shape in which the opening dimension gradually increases toward the opening side of the recess. For example, the inner wall surface is composed of a linear tapered surface. In addition, it is a concept including an inner wall surface formed of an arc surface. If it does in this way, it will become easy to expand a part which becomes the above-mentioned trace part finally as the above-mentioned end face of a work material is expanded. In particular, it is desirable that the above-mentioned recess is formed by forging to obtain a first intermediate product, that is, it is preferable to mold the rod-shaped material at the same time as forming the first intermediate product.

  When a mortar-shaped recess is formed on the end surface of the workpiece, the Nth intermediate product is obtained by changing the cross-sectional shape of the recess as the end surface of the workpiece is expanded in diameter. Can do.

  In the above configuration, the manufacturing method of the outer joint member according to the present invention may further include a finishing step of finishing the final forged product into a finished product shape. In this case, the above-described trace is removed in this finishing step. be able to.

  In the above configuration, it is desirable that the ironing process is performed cold. This is because it is possible to increase the service life of the ironing die while increasing the forming accuracy of the final forged product, which is advantageous in producing a highly accurate outer joint member at low cost.

  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 the outer joint member of the quick universal joint. The present invention also provides an outer joint member in which each track groove is composed of a linear portion and an arc-shaped portion, such as an undercut-free type constant velocity universal joint (UJ) or a barfield type constant velocity universal joint (BJ). It can also be applied when manufacturing an outer joint member of a fixed type constant velocity universal joint represented by.

  The present invention can also be preferably applied to the manufacture of an outer joint member that integrally has a shaft portion that extends in the axial direction from the bottom portion of the cup portion.

  Moreover, in order to solve said subject, the outer side for constant velocity universal joints which have the bottomed cylindrical cup-shaped part which one end opened, and were provided with several track grooves extended in the axial direction on the internal diameter surface of the cup part It is an intermediate forged product processed into a joint member, and has a cup-shaped part formed into a bottomed cylindrical shape by forging a bar-shaped material, and ironing is performed on this cup-shaped part The track groove formed roughly on the inner diameter surface of the cup-shaped portion is formed into a finished shape, and the end edge of the rod-shaped material is deformed on the opening end surface of the cup-shaped portion. Provided is an intermediate forged product provided with a mark portion.

  In the case of such an intermediate forged product, even if ironing is performed on the cup-shaped portion constituting the intermediate forged product, the inner surface of the cup-shaped portion after ironing, and thus the cup portion constituting the outer joint member, is described above. Since a situation in which a trace (projection such as a burr) enters is prevented as much as possible (the occurrence rate of defective products is reduced as much as possible), the product yield can be increased. In this case, it is not necessary to perform a finishing process for removing the protrusion generated at the outer peripheral edge of one end of the rod-shaped material, and it is possible to use a rod-shaped material obtained by cutting or shearing a long rod material into a predetermined dimension. it can. Therefore, a high quality outer joint member capable of exhibiting desired joint performance can be manufactured at low cost.

  Moreover, in order to solve said subject, it has the bottomed cylindrical cup part which one end opened, and the outer joint for constant velocity universal joints provided with the several track groove extended in the axial direction on the internal diameter surface of a cup part The inner diameter surface of the cup-shaped portion of the intermediate forged product, which is a final forged product processed into a member, and ironing the cup-shaped portion formed into a bottomed cylindrical shape by forging the rod-shaped material In an endless trace formed by deforming the outer peripheral edge of one end of the rod-shaped material on the opening end surface of the cup-shaped part formed with the ironing process, in which the track groove that is roughly formed into a finished shape is formed The final forging product characterized by being provided is provided.

  If it is such a final forged product, it can enjoy the same effect as the intermediate forged product which concerns on this invention mentioned above.

  As described above, according to the present invention, a high quality outer joint member can be manufactured at low cost.

(A) A figure is a top view of the outer joint member manufactured using the manufacturing method concerning the embodiment of the present invention, and (b) figure is a schematic sectional view of the outer joint member. (A) is a schematic plan view and front view of a rod-shaped material, and (b) to (d) are first to first forging steps among the steps included in the manufacturing method according to the first embodiment of the present invention. It is the schematic plan view and front view of the halfway product which are obtained in the 3rd stage, respectively. It is a figure which shows typically the mode of back extrusion performed at the 4th step of a pre-forging process. (A) is a schematic plan view of an intermediate forged product, and (b) is a front view including a cross-section taken along line XX shown in (a). (A) is a schematic plan view and a front view of a rod-shaped material, and (b) to (d) are first to first forging steps among steps included in the manufacturing method according to the second embodiment of the present invention. It is the schematic plan view and front view of the halfway product which are obtained in the 3rd stage, respectively. (A) The figure is a schematic plan view and a front view of the rod-shaped material, and (b) to (d) are the first to first forging steps among the steps included in the manufacturing method according to the third embodiment of the present invention. It is the schematic plan view and front view of the halfway product which are obtained in the 3rd stage, respectively. It is a figure which shows typically the mode of the upsetting process for shape | molding the intermediate product shown in FIG.6 (c) into the intermediate product shown in FIG.6 (d). (A) The figure is a schematic plan view and a front view of the rod-shaped material, and (b) to (d) are the first to first forging steps among the steps included in the manufacturing method according to the fourth embodiment of the present invention. It is the schematic plan view and front view of the halfway product which are obtained in the 3rd stage, respectively. (A) The figure is a figure which shows typically the mode of back extrusion processing for shape | molding the intermediate product shown in FIG.6 (d) to the intermediate forging goods shown in FIG. 4, (b) A figure is (a) figure. It is a figure which shows the modification of the punch shown. (A) It is a figure which shows typically the modification of the recessed part provided in the one end surface of a product in the middle of (b) figure. It is a schematic sectional drawing which shows the modification of the outer joint member which can be manufactured using the manufacturing method which concerns on this invention. It is a principal part expanded sectional view of a rod-shaped raw material.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, for convenience, an example of an outer joint member manufactured using the manufacturing method according to the present invention will be described first, and then an embodiment of the method of manufacturing the outer joint member according to the present invention will be described.

  FIG. 1A shows a schematic plan view of an outer joint member 1 for a constant velocity universal joint (hereinafter simply referred to as “outer joint member 1”), and FIG. 1B shows a schematic cross-sectional view of the outer joint member 1. (X1-X1 arrow directional cross-sectional view of Fig.1 (a)) is shown. This outer joint member 1 is an outer joint member for a tripod type constant velocity universal joint that is a kind of sliding type constant velocity universal joint that allows both angular displacement and axial displacement, and includes a cylindrical portion 2a and a bottom portion 2b. The bottomed cylindrical cup portion 2 having an opening on the opposite side in the axial direction of the bottom portion 2b and the shaft portion 3 extending axially outward from the bottom portion 2b of the cup portion 2 are integrally provided. Although not shown, 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 on the inner diameter surface 4 of the cup portion 2 at equal intervals in the circumferential direction. Each track groove 5 has a pair of roller guide surfaces 6 and 6 that face each other in the circumferential direction, and is formed in a straight line including the roller guide surfaces 6 and 6 and extending parallel to the axis. As shown in FIG. 1 (a), the cup portion 2 is formed into a cross-sectional corolla shape in which three large diameter portions and small diameter portions are alternately arranged in the circumferential direction, and the inner circumference of each large diameter portion. A track groove 5 is formed on the surface. An entrance chamfer 7 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 to allow angular displacement of the joint. Moreover, the circumferential direction groove | channel 8 by which the one end part of the boot which seals the inside of a coupling is fitted is provided in the outer-diameter surface of the cup part 2. As shown in FIG.

  Hereinafter, it is an example of the manufacturing method of the outer joint member 1 mentioned above, Comprising: 1st Embodiment of the manufacturing method which concerns on this invention is described in detail, referring drawings. Roughly speaking, the outer joint member 1 described above includes a pre-forging step of forming the bar-shaped material M shown in FIG. 2 (a) into the intermediate forged product 21 shown in FIGS. 4 (a) and 4 (b), an intermediate forged product 21. It is completed through an ironing process for forming the final forged product, a finishing process for finishing each part of the final forged product into a finished product shape, a heat treatment step for heat-treating the final forged product finished in the finished product shape, and the like.

  In the pre-forging step in the present embodiment, as shown in FIGS. 2A to 2D, the rod-shaped material M is sequentially turned into a first intermediate product M1, a second intermediate product M2, and a third intermediate product M3. After forming, the intermediate forged product 21 having the cup-shaped portion 22 shown in FIGS. 4 (a) and 4 (b) is formed. That is, in the pre-forging process of the present embodiment, the rod-shaped material M is formed into the intermediate forged product 21 by executing four forging processes stepwise. In addition, although detailed illustration is abbreviate | omitted, the pre-forging process is a transfer means for automatically transferring a workpiece (workpiece) between adjacent forging dies in a series of four forging dies. It is performed using a forging device (transfer press) equipped with Each forging process in the pre-forging step is performed in a state where at least the molding surface of the forging die is lubricated with a lubricant such as a lubricating oil.

  Before explaining the details of each forging process executed stepwise in the pre-forging step, the rod-shaped material M will be described. As the rod-shaped material M shown in FIG. 2 (a), a long rod (not shown) is cut or sheared to a predetermined size as it is (without being subjected to finishing or the like), or a little after cutting / shearing. Used by chamfering. For this reason, protrusions 102 (see FIG. 12) such as burrs and edges generated when cutting or shearing a long bar are intermittently or continuously left on the outer peripheral edge Mb of the bar-shaped material M. There may be. In some cases, the rod-shaped material M may be produced around the pre-forging process, or may be produced in a place different from the pre-forging process and then transported / conveyed to the pre-forging process. There is also.

  In the first stage of the pre-forging process, the rod-shaped material M is upset by a first forging die (not shown), and the rod-shaped material M is formed into a first intermediate product M1 shown in FIG. . In the upsetting process for the rod-shaped material M, the diameter dimension of the one end surface M1a of the first intermediate product M1 is larger than the diameter dimension of the one end surface Ma of the rod-shaped material M, and the one end surface M1a of the first intermediate product M1 is formed. The first end portion M1b having an endless shape (here, substantially circular shape) formed by deforming (expanding deformation) one end outer peripheral edge portion Mb of the rod-shaped material M is disposed at a position near the outer diameter end. The The first mark portion M1b has a turn-up shape (projection shape) in which a part or all of the first mark portion M1b protrudes outward in the axial direction, but is indicated by a dotted line in FIG. The same applies to the second mark part M2b, the third mark part M3b, and the fourth mark part M4b described below.

  In the second stage of the pre-forging step, the first intermediate product M1 is subjected to forward extrusion processing by a second forging die (not shown), and the first intermediate product M1 is, as shown in FIG. It is molded into a second intermediate product M2 having a shaft-like portion 13 (a portion finally finished to the shaft portion 3) on the other end side (lower side in the figure). More specifically, in the forward extrusion process for the first intermediate product M1, the other end side of the first intermediate product M1 is formed into the shaft-shaped portion 13, and one end face M1a of the first intermediate product M1 and the first intermediate product M1 are formed. The process is performed so that both the first mark portions M1b existing in the one end face M1a are expanded in diameter. Therefore, the second intermediate product M2 has a diameter dimension of the one end face M2a larger than a diameter dimension of the one end face M1a of the first intermediate product M1, and the first mark M1b is deformed on the one end face M2a ( The second mark portion M2b having a substantially perfect circle shape formed by diameter expansion deformation) is provided. The diameter dimension of the one end face M2a of the second intermediate product M2 is 85% or more with respect to the diameter dimension of the molding punch 32 (see FIG. 3) used in the fourth stage of the pre-forging process. desirable.

  In the third stage of the pre-forging process, the second intermediate product M2 is upset by a third forging die (not shown), and the second intermediate product M2 is, as shown in FIG. It is molded into a third halfway product M3 that integrally has an upsetting portion 12 having a substantially corollary cross section and a shaft-like portion 13. More specifically, the upsetting process for the second intermediate product M2 includes pressurizing one end face M2a of the second intermediate product M2 arranged on the inner periphery of the die (not shown) with a punch (not shown) and including the one end face M2a. The portion is expanded and deformed in the radial direction (both the one end surface M2a of the second intermediate product M2 and the second scar M2b existing in the one end surface M2a are expanded in diameter). Therefore, the third intermediate product M3 has a diameter dimension (minimum diameter dimension) of one end face M3a larger than a diameter dimension of the one end face M2a of the second intermediate product M2, and one end face M3a of the upsetting portion 12. Inside, the second mark part M2b has an endless third mark part M3b formed by expanding and deforming.

  In the fourth stage of the pre-forging process, as shown in FIG. 3, the fourth forging die 30 having the coaxially arranged die 31 and cup-shaped part forming punch 32 is extruded backward into the third intermediate product M3. Processing (cup forming processing) is performed, and the third intermediate product M3 is formed into an intermediate forged product 21 integrally having the cup-shaped portion 22 and the shaft-shaped portion 13 shown in FIGS. 4 (a) and 4 (b). Accordingly, in the present embodiment, the third intermediate product M3 corresponds to the “Nth intermediate product” in the present invention. For this reason, in the third halfway product M3, the third trace M3 existing on the one end face M3a is entirely formed on the one end face M3a of the third halfway product M3 by the molding punch 32 of the cup-like portion 22. It arrange | positions radially outside a to-be-pressurized area | region (refer FIG. 3).

  As shown in FIG. 3, in the backward extrusion process for the third intermediate product M3, the third intermediate product M3 is disposed on the inner periphery of the die 31, and then the die 31 and the punch 32 are relatively moved in the axial direction. The punch 32 is gradually pushed into the substantially central region of the upsetting portion 12 of the third intermediate product M3. Then, as the punch 32 is gradually pushed in, the flesh of the upsetting portion 12 is gradually plastically deformed so as to follow the outer peripheral molding surface of the punch 32 and the inner peripheral molding surface of the die 31. As a result, as shown in FIGS. 4A and 4B, the cup-shaped portion 22 having the track groove 5 ′ roughly formed in the circumferentially divided position of the inner diameter surface and the shaft-shaped portion 13 are integrated. The intermediate forging product 21 is obtained. An open end surface of the cup-shaped portion 22 of the intermediate forged product 21 is provided with an endless fourth mark portion M4b formed by deforming the third mark portion M3b. Note that this rear extrusion process proceeds in a state where the radial deformation of the upsetting portion 12 is regulated by the die 31. Therefore, the diameter dimension (minimum diameter dimension) of the opening end face of the cup-shaped part 22 is substantially equal to the diameter dimension of the one end face M3a of the third intermediate product M3, and the fourth trace part M4b is substantially the same as the third trace part M3b. Exhibits the same shape.

  Each forging process described above is performed in any temperature range between cold, warm, sub-hot, or hot as long as the workpiece (rod-like material M and intermediate products M1 to M3) can be formed into a predetermined shape. It may be executed with. Note that cold forging is a technique for forging a workpiece that is approximately 200 ° C. or less, and warm forging is for a workpiece heated to approximately 600 to 700 ° C. This is a technique for forging. Sub-hot forging is a technique for forging a workpiece heated to approximately 750 to 1000 ° C., and hot forging is a workpiece heated to approximately 1000 to 1200 ° C. This is a technique for forging a workpiece.

  The intermediate forged product 21 produced as described above is transferred to the ironing process. Although detailed illustration of the ironing process is omitted, in the process, ironing is performed on the intermediate forged product 21 by using ironing dies and ironing punches arranged coaxially. By this ironing process, the track groove 5 ′ roughly formed on the inner diameter surface of the cup-shaped portion 22 of the intermediate forged product 21 is formed into a finished shape. That is, the intermediate forged product 21 is formed into a final forged product having a cup-shaped portion having a finished track groove on the inner diameter surface. The cup depth of the final forged product varies depending on the use of the outer joint member 1 and, in turn, the constant velocity universal joint using this as a component, but is generally in the range of 30 mm to 150 mm.

  The final forged product is finished into a finished product shape in the finishing process. That is, in the finishing process, for example, a circumferential groove 8 to be provided on the outer diameter surface of the cup portion 2 or a spline to be provided on the outer diameter of the free end of the shaft portion 3 is formed by machining. Is finished to the finished product shape. In this finishing process, the open end surface of the cup-shaped portion constituting the final forged product may be finished to a flat surface (the endless trace M4b existing on the open end surface may be removed) or may not be finished to a flat surface. (The endless trace M4b existing on the opening end face may not be removed). That is, the outer joint member 1 may be used while the opening end portion of the cup portion 2 maintains the state (shape) after the ironing process. And the outer joint member 1 shown in FIG. 1 is completed by performing heat processing, such as quenching, on the final forged product that has been finished into a finished product shape as a whole.

  As described above, in the present invention, the third outer peripheral product M3 as the Nth intermediate product manufactured in the pre-forging process is formed by deforming one end outer peripheral edge Mb of the rod-shaped material M on one end face M3a. It has an endless trace (third trace M3b), and the entire third trace M3b is formed by the molding punch 32 of the cup-shaped portion 22 in the forging die used in the pre-forging process. The one end face M3a is disposed on the outer side in the radial direction than the pressurized area. In this way, even when the rod-shaped material M having a protrusion 102 (see FIG. 12) such as a burr along the outer peripheral edge Mb at one end thereof is used, the protrusion is formed on the inner diameter surface of the cup-shaped portion 22. It is possible to prevent as much as possible the production of the intermediate forged product 21 into which 102 has entered, as well as the final forged product, and further the outer joint member 1. That is, it is possible to obtain the intermediate forged product 21 in which the protrusion 102 is provided in the opening end surface of the cup-shaped portion 22, and thus the outer joint member 1 provided in the opening end surface of the cup portion 2. And since the opening end surface of the cup part 2 of the outer joint member 1 is not a surface to which another member is attached or the other member contacts, the projection 102 exists in the opening end surface of the cup part 2. Even if it exists, the joint performance is not adversely affected. Therefore, it is not always necessary to perform the finishing process for removing the protrusion 102 generated at the outer peripheral edge Mb at the one end of the rod-shaped material M. From the above, the high-quality outer joint member 1 that can exhibit desired joint performance can be manufactured at low cost.

  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, among the forging processes executed in order to obtain the first to third intermediate products M1 to M3 in the pre-forging step, the third intermediate product M3 among the workpieces is forged. A concave portion having a mortar shape as a whole on the end surface that becomes the one end surface M3a and a portion that becomes the third mark portion M3b on the inner wall surface can be formed. FIG. 5 shows an example in which such a method is employed, and the concave portion is formed in a forging step for obtaining the first intermediate product M1, that is, in the first step of the pre-forging step.

  More specifically, in the first stage of the pre-forging process in the second embodiment, the rod-shaped material M shown in FIG. When the first intermediate product M1 larger than the diameter dimension of the one end surface Ma is obtained, the recess C opened in the one end surface M1a of the first intermediate product M1 is molded [see FIG. 5B]. The concave portion C includes a tapered inner wall surface Ca inclined in a direction in which the opening size of the concave portion C is gradually enlarged toward the opening side (one end surface M1a side) of the concave portion C, and an inner bottom surface extending in a direction perpendicular to the axis. It is defined by Cb and has a mortar shape as a whole. In the vicinity of the opening end (outer diameter end) of the inner wall surface Ca of the recess C, an endless first mark portion M1b formed by deforming one end outer peripheral edge portion Mb of the rod-shaped material M is disposed. In the present embodiment, the recess C is open to the entire end surface M1a of the first intermediate product M1.

  In addition, the cross-sectional shape of the recessed part C can be selected / changed arbitrarily, for example, it is good also as a form as shown to Fig.10 (a) (b). FIG. 10A shows a recess C in which the inner wall surface Ca is constituted by a plurality of arc surfaces and / or tapered surfaces connected to each other, and FIG. 10B is constituted by a single arc surface (spherical surface). A recessed portion C is shown. The same applies to other embodiments described later.

  Next, when the first intermediate product M1 is subjected to forward extrusion processing in the second stage of the pre-forging process and the first intermediate product M1 is formed into the second intermediate product M2, FIG. As shown, the diameter dimension of the one end face M2a of the second intermediate product M2 is larger than the diameter dimension of the one end face M1a of the first intermediate product M1, and the recess is opened in the one end face M2a of the second intermediate product M2. The inclination angle of the inner wall surface Ca of C (specifically, the inclination angle with respect to the axis perpendicular to the axis. The same applies to the case of “inclination angle” hereinafter) θ2 The first midway product M1 is subjected to forward extrusion so as to be larger than the inclination angle θ1 of the inner wall surface Ca. That is, although illustration is omitted, the inclination angle of the tip pressing surface that pressurizes the one end face M1a of the first intermediate product M1 is the inclination of the inner wall surface Ca of the recess C opened in the one end face M1a of the first intermediate product M1. Using a punch larger than the angle θ1, the first intermediate product M1 is subjected to forward extrusion. The diameter dimension d2 of the inner bottom surface Cb of the recess C opened in the one end surface M2a of the second intermediate product M2 is the diameter dimension d1 of the inner bottom surface Cb of the recess C opened in the one end surface M1a of the first intermediate product M1. Is smaller than

  Next, when the second intermediate product is upset in the third stage of the pre-forging process and the second intermediate product M2 is formed into the third intermediate product M3, it is shown in FIG. 5 (d). As described above, the diameter dimension (minimum diameter dimension) of the one end face M3a of the third intermediate product M3 is larger than the diameter dimension of the one end face M2a of the second intermediate product M2, and the one end face M3a of the third intermediate product M3. The second intermediate product is set such that the inclination angle θ3 of the inner wall surface Ca of the recess C opened in the upper portion is larger than the inclination angle θ2 of the inner wall surface Ca of the recess C opened in one end face M2a of the second intermediate product M2. M2 is upset. That is, although illustration is omitted, the inclination angle of the pressurizing surface that pressurizes the one end face M2a of the second intermediate product M2 is the inclination angle of the inner wall surface Ca of the recess C opened in the one end face M2a of the second intermediate product M2. Using a punch larger than θ2, the second intermediate product M2 is upset. The diameter dimension d3 of the inner bottom surface Cb of the recess C opened in the one end face M3a of the third intermediate product M3 is the diameter dimension d2 of the inner bottom surface Cb of the recess C opened in the one end face M2a of the second intermediate product M2. Is smaller than

  Then, in the fourth stage of the pre-forging process, the third intermediate product M3 shown in FIG. 5 (d) is obtained by subjecting the third intermediate product M3 to backward extrusion in the same manner as in the first embodiment described above. The intermediate forged product 21 shown in FIGS. 4 (a) and 4 (b) is formed. Since the subsequent steps are the same as those in the first embodiment described above, the description thereof is omitted.

  If the first to third stages in the pre-forging process are performed in the above-described manner, it is easy to increase the diameter of the one end face M1a of the first intermediate product M1 and the one end face M2a of the second intermediate product M2. Therefore, the first mark portion M1b existing on the one end face M1a of the first intermediate product M1 and the second mark portion M2b existing on the one end face M2a of the second intermediate product M2 can be easily expanded together, and therefore the third mark The entire third mark M3b provided in the one end surface M3a of the halfway product M3 is radially outer than the pressurized area of the one end surface M3a of the third halfway product M3 by the molding punch 32 of the cup-shaped portion 22. It becomes easy to arrange. As a result, even when a protrusion 102 (see FIG. 12) such as a burr is generated on the outer peripheral edge portion Mb of one end of the rod-shaped material M as the rod-shaped material M is manufactured, the protrusion 102 becomes the inner diameter of the cup-shaped portion 22. The possibility that an intermediate forged product 21 that has entered the surface, that is, a defective product of the intermediate forged product 21 is manufactured can be effectively reduced.

  By performing each forging process in the first to third stages of the pre-forging process in the following manner, it is possible to achieve the same effects as described above. More specifically, in the first stage of the pre-forging step, as shown in FIG. 6B, the concave portion in which the inclination angle θ1 of the inner wall surface Ca is larger than that of the concave portion C shown in FIG. An upsetting process is performed on the rod-shaped material M so that a first intermediate product M1 having C opened at one end face M1a is obtained. Next, in the second stage of the pre-forging process, as shown in FIG. 6C, the inclination angle θ2 (depth dimension of the recess C) of the inner wall surface Ca of the recess C is larger than that in the first intermediate product M1. The first halfway product M1 is subjected to a forward extrusion process so that the second halfway product M2 that is also larger is obtained. Then, in the third stage of the pre-forging process, as shown in FIG. 6 (d), the inclination angle θ3 (depth dimension of the recess C) of the inner wall surface Ca of the recess C is larger than that in the second intermediate product M2. An upsetting process is performed on the second intermediate product M2 so that a sufficiently small third intermediate product M3 is obtained. Incidentally, the size relationship of the diameter dimension of the inner bottom surface Cb of the recess C provided in each of the first to third intermediate products M1 to M3 is d2 <d1 <d3.

  When the second intermediate product M2 shown in FIG. 6C is formed into the third intermediate product M3 having the upsetting portion 12 shown in FIG. 6D, the forging die shown in FIG. (Sealed forging die) 40 is used. A forging die 40 shown in the figure includes a die 41 and a punch 42 that are coaxially arranged, and is internally lubricated (at least an inner diameter surface 41a of the die 41 and a tip pressurizing surface 42a of the punch 42 such as a lubricant such as lubricating oil). Is used). Note that the shape of the inner diameter surface 41a of the die 41 corresponds to the outer peripheral shape of the third intermediate product M3 (the upsetting portion 12) to be molded, and the shape of the tip pressing surface 42a of the punch 42 is the third intermediate portion to be molded. This corresponds to the shape of the one end face M3a (concave C) of the product M3.

  In the forging die 40 having the above-described configuration, when the second intermediate product M2 is disposed on the inner periphery of the die 41 and the punch 42 is moved downward, the second pressurizing surface 42a of the punch 42 causes the second pressurization surface 42a as shown in FIG. In the middle of the process, the entire end face M2a of the product M2 is covered, that is, the opening of the recess C is closed. At this time, a space is defined between the tip pressure surface 42a of the punch 42 and the recess C of the second intermediate product M2, and the lubricant F applied to the tip pressure surface 42a of the punch 42 and the like in this space. Is contained. When the volume of the space is reduced as the punch 42 is moved downward, the pressure of the lubricant F contained in the space is excessively increased and the second intermediate product M2 is increased. There is a risk of scratches or chipping. Therefore, when the second intermediate product M2 shown in FIG. 6 (c) is formed into the third intermediate product M3 shown in FIG. 6 (d), as shown in FIG. A punch 42 provided with a communication hole 43 for communicating the above-described space with the atmosphere is used. Thereby, generation | occurrence | production of the said malfunction resulting from the excessive pressure rise of the lubricant F can be prevented as much as possible, and the high quality outer joint member 1 can be manufactured.

  In the embodiment described with reference to FIGS. 6A to 6D, in the third stage of the pre-forging process, the inclination angle θ3 (the depth dimension of the recess C) of the inner wall surface Ca of the recess C is the second. The third intermediate product M3 that is sufficiently smaller than that in the intermediate product M2 is obtained. However, in the third stage of the pre-forging process, as shown in FIG. Of the second intermediate product M2 so as to obtain a third intermediate product M3 having an inclination angle θ3 (depth dimension of the concave portion C) larger than that of the second intermediate product M2. It can also be applied.

  The third intermediate product M3 shown in FIG. 8 (d) is subjected to backward extrusion processing in the same manner as in the first embodiment described above in the fourth stage of the pre-forging process, so that FIG. 4 (a). The intermediate forged product 21 shown in FIG. At this time, the second intermediate product M2 shown in FIG. 6C is shown in FIG. 6C because the recess C having a large inclination angle θ3 of the inner wall surface Ca is opened on the one end face M3a of the third intermediate product M3. There is a possibility that the same problem as in the case of forming the third intermediate product M3 shown in FIG.

  That is, in order to obtain the intermediate forged product 21 as shown in FIGS. 4 (a) and 4 (b), it is necessary to subject the third intermediate product M3 to backward extrusion using the forging die 30 shown in FIG. However, because the inclination angle of the tip pressing surface 32a of the punch 32 is smaller than the inclination angle θ3 of the surface to be pressed (the inner wall surface Ca of the recess C) of the third intermediate product M3, A space is defined between the third intermediate product M3 and the recess C, and the lubricant F applied to the tip pressurizing surface 42a of the punch 32 and the like is enclosed in the space [see FIG. 9A]. . Then, when the volume of the space is reduced as the lowering movement of the punch 32 proceeds, the pressure of the lubricant F contained in the space is excessively increased accordingly, and the third intermediate product M3 is formed. There is a risk of scratches or chipping. Therefore, when the third intermediate product M2 shown in FIG. 8 (d) is formed into the intermediate forged product 21 shown in FIGS. 4 (a) and 4 (b), as shown in FIG. A punch 32 provided with a communication hole 33 for communicating the space defined by the pressure surface 32a with the atmosphere is used. Thereby, generation | occurrence | production of the said malfunction resulting from the excessive pressure rise of the lubricant F can be prevented as much as possible, and the high quality outer joint member 1 can be obtained.

  The communication hole 33 to be provided in the punch 32 can be formed by a hole drilled by machining or the like as shown in FIG. 9 (a), and the punch hole 32 as shown in FIG. 9 (b). 32 can be constituted by a gap formed between the members 34 and 35 by constituting the cylindrical outer member 34 and an inner member 35 arranged with a gap fit on the inner periphery of the outer member 34. Although illustration is omitted, the same configuration can be applied to the punch 42 shown in FIG.

  Although the present invention has been applied to the case where the forging process is executed in four stages in the pre-forging process (when the intermediate forged product 21 is obtained through four forging processes), the forging process is performed in three or five stages in the pre-forging process. The present invention can be preferably applied to the above execution.

  In addition, as shown in FIG. 11, the present invention can be preferably applied when manufacturing an outer joint member 1 having a recess 9 opened at a joint axis position on the inner bottom surface of the cup portion 2. In addition, this recessed part 9 is provided in order to center the workpiece | work (at least one of the intermediate product, the intermediate forging product 21, and the final forging product) processed into the outer joint member 1, and the punch which pressurizes the said workpiece | work. It is a part.

  In the above, the present invention is applied when manufacturing 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. However, the present invention is a double offset type. The invention can also be preferably applied to the production of outer joint members of other sliding constant velocity universal joints such as constant velocity universal joints (DOJ).

  Furthermore, the manufacturing method according to the present invention is not limited to the case of manufacturing an outer joint member of a sliding type constant velocity universal joint that allows both angular displacement and axial displacement, but also a fixed constant velocity that allows only angular displacement. The present invention can also be applied to the production of outer joint members of universal joints, for example, Barfield type constant velocity universal joints (BJ) and undercut free type constant velocity universal joints (UJ). In the outer joint member of the fixed type constant velocity universal joint, a plurality of track grooves provided on the inner diameter surface of the cup portion are constituted by a linear portion and an arc-shaped portion.

DESCRIPTION OF SYMBOLS 1 Outer joint member 2 Cup part 3 Shaft part 5 Track groove 6 Guide surface 12 Upset part 13 Shaft-shaped part 21 Intermediate forged product 22 Cup-shaped part C Recessed part Ca Inner wall surface F Lubricant M Rod-shaped material M1 First intermediate product M2 Second intermediate product M3 Third intermediate product Ma, M1a, M2a, M3a One end face Mb One outer peripheral edge M1b First trace M2b Second trace M3b Third trace

Claims (11)

A method of manufacturing an outer joint member for a constant velocity universal joint having a bottomed cylindrical 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,
By executing multiple forging processes step by step, the rod-shaped material is sequentially formed into the first to N-th intermediate products (N is a positive integer of 2 or more), and then the track groove is roughly formed on the inner diameter surface. Including a pre-forging step of forming an intermediate forged product having a bottomed cylindrical cup-shaped portion, and a squeezing step of forming the intermediate forged product into a final forged product having a finished-shaped track groove,
The N-th intermediate product produced in the intermediate stage of the pre-forging process has an endless trace formed by deforming the outer peripheral edge of one end of the rod-shaped material on one end face, and the entire trace is Among the forging dies used in the pre-forging process, the constant-velocity freedom is characterized in that the cup-shaped portion is arranged on the outer side in the radial direction with respect to the pressed area of the one end surface by the molding punch. A method of manufacturing an outer joint member for a joint.   The method for producing an outer joint member for a constant velocity universal joint according to claim 1, wherein a rod-shaped material obtained by cutting or shearing a long bar material into a predetermined dimension is used as it is.   In the forging process executed in the first stage of the pre-forging process, a first intermediate product is obtained in which a portion to be the trace is provided on an end surface which is one end surface of the N-th intermediate product, and then the first In at least one forging process that is performed until an intermediate product of N is obtained, an end surface that becomes one end surface of the N-th intermediate product and a portion that becomes the trace portion provided on the end surface of the workpiece The method for manufacturing the outer joint member for a constant velocity universal joint according to claim 1, wherein the N-th intermediate product is obtained by expanding the diameter of the joint.   Among the forging processes for obtaining the first to Nth intermediate products, in any one forging process, among the workpieces, the end surface that is one end surface of the Nth intermediate product has a mortar shape, The manufacturing method of the outer joint member for constant velocity universal joints of Claim 3 which shape | molds the recessed part in which the site | part used as the said trace part was provided in the inner wall surface.   The manufacturing method of the outer joint member for constant velocity universal joints of Claim 4 which shape | molds the said recessed part by the forge process for obtaining a 1st intermediate product.   6. The outer joint member for a constant velocity universal joint according to claim 4, wherein the N-th intermediate product is obtained by changing a cross-sectional shape of the recess as the end surface of the workpiece is enlarged. Manufacturing method.   The method for producing an outer joint member for a constant velocity universal joint according to any one of claims 1 to 6, further comprising a finishing step of finishing the final forged product into a finished product shape, wherein the trace is removed in the finishing step. .   The manufacturing method of the outer joint member for constant velocity universal joints as described in any one of Claims 1-7 applied to what a track groove comprises only a linear part.   The manufacturing method of the outer joint member for constant velocity universal joints as described in any one of Claims 1-7 applied to what a track groove is comprised by a linear part and an arc-shaped part. It is an intermediate forged product that is machined into an outer joint member for a constant velocity universal joint that has a bottomed cylindrical 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 cup-shaped portion formed into a cylindrical shape with a bottom by subjecting the rod-shaped material to forging, and the cup-shaped portion is subjected to ironing to roughly form the inner surface of the cup-shaped portion. In the track groove that is formed into a finished shape,
An intermediate forged product characterized in that an endless trace formed by deforming an outer peripheral edge of one end of a rod-shaped material is provided on an opening end face of the cup-shaped part. This is a final forged product that is processed into an outer joint member for a constant velocity universal joint that has a bottomed cylindrical 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. Then, by forging the rod-shaped material, the inner forged product having a cup-shaped portion formed into a bottomed cylindrical shape is subjected to ironing to roughly form the inner surface of the cup-shaped portion of the intermediate forged product. In the track groove formed into a finished shape,
A final forged product characterized in that an endless trace formed by deforming an outer peripheral edge of one end of a rod-shaped material is provided on an opening end face of a cup-shaped part formed in accordance with the ironing process.

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