JP2016068107A - Molding method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a molding method capable of molding a product having no flaw at least on the inner surface of a cylinder part, namely a cup-shaped member, without performing chamfering or shot blasting to a cylindrical raw material.SOLUTION: In a molding method, a preforming body is molded by a forging die for preforming by using a cylindrical raw material formed by cutting a bar stock, and then a cup-shaped member having a bottomed cylindrical shape is obtained by a forging die for molding. The preforming body is compressed in the axial direction by the forging die for molding, to thereby push out a raw material on the outer peripheral side in the reverse direction to the compression direction. Hereby, the cup-shaped member is obtained, in which a corner part of the cylindrical raw material is arranged on a bottom wall.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a molding method for molding a bottomed cylindrical cup-shaped member.

  The cup-shaped member having a bottomed cylindrical shape includes a cylindrical portion and a bottom wall that closes a lower opening of the cylindrical portion. And in the shaping | molding of such a cup-shaped member, it can shape | mold by the hot forging method of the cup-shaped blank described in patent document 1, etc., for example.

  In the hot forging method of Patent Document 1, a disk-shaped upset body in which a cylindrical body is preformed in the axial direction is formed, the upset body is stored in a cup-shaped die, and a cup-shaped blank is formed. The cross section on the center line is forged by backward extrusion with a T-shaped punch.

  In general, the cup-shaped member is formed by the steps shown in FIGS. First, the bar is cut by sawing or shearing to form a cylindrical material 1 (1A) (1B) as shown in FIGS.

  Thereafter, as shown in FIG. 8A, a disk-shaped preform 4 as shown in FIG. 8B is formed using a forging die provided with a punch 2 and a die 3. That is, the cylindrical material 1 is compressed in the axial direction with the punch 2 and the die 3. Next, as shown in FIGS. 9 (a) and 9 (b), the preformed body 4 is formed into a cup-shaped member by using a forging die for forming provided with a punch 5 and a die 6 made of a bottomed cylindrical body. 7 to form. The die 6 of the forging die for forming includes a bottom wall 6b and a peripheral wall 6a rising from the outer peripheral portion of the bottom wall 6b.

  That is, as shown in FIG. 9A, after the preform 4 is accommodated in the die 6, the punch 5 is placed on the preform 4 in the die 6 as shown in FIG. 9B. The preform 4 is compressed in the axial direction by being pushed down along the axial direction. In that case, the raw material of the outer peripheral part of the preform 4 is extruded to the opposite side to the compression direction. For this reason, the gap 9 is filled between the outer peripheral surface 5 a of the punch 5 and the inner peripheral surface 8 of the peripheral wall 6 a of the die 6. Thereby, the cup-shaped member 7 is molded. The cup-shaped member 7 includes a cylindrical portion 7a and a bottom wall 7b that closes a lower opening of the cylindrical portion 7a.

JP 2009-183974 A

  By the way, in the above forming methods, cylindrical materials 1 (1A) and (1B) shown in FIGS. 10 (a) and 10 (b) are used. As described above, the columnar material 1 is formed by cutting a bar material by saw cutting or shearing. For this reason, burrs 10 are often formed at the corners of the columnar material 1.

  For example, when the cylindrical material 1A of FIG. 10A is used and 10a is formed as a burr, as shown in FIG. 8B, when the disk-shaped preform 4 is formed. The burr 10a remains on the outer diameter side of the upper surface of the preform 4. Thus, if the burr | flash 10a remains, when the cup-shaped member 7 is shape | molded as shown to Fig.9 (a), there exists a possibility of producing the collar 11 in the cylindrical part 7a of the cup-shaped member 7. FIG. Moreover, there exists a possibility that the same wrinkle 11 may be produced also in the corner | angular part of the columnar raw material 1. FIG.

  Therefore, conventionally, it has been necessary to perform chamfering, shot blasting, or the like on the cylindrical material 1 to remove the burrs 10 or round corners. For this reason, it cannot be molded using equipment for cutting in a molding machine such as a former, resulting in poor productivity. Here, the former is a machine that cuts a supplied material into a certain size, carries it between a plurality of opposing “molds”, and forms a material by applying pressure between the molds.

  In view of the above problems, the present invention can form a product that does not cause wrinkles at least on the inner surface of the cylindrical portion, that is, a cup-shaped member, without performing chamfering or shot blasting on a cylindrical material. A possible molding method is provided.

  In the molding method of the present invention, after forming a preform with a forging die for preforming using a columnar material formed by cutting a bar, a cup shape with a bottomed cylindrical shape is formed with a forging die for molding. A molding method for obtaining a member, wherein the preform is compressed in the axial direction with a forging die for molding, the outer peripheral side material is extruded in the direction opposite to the compression direction, and the corners of the columnar material are bottomed. A cup-shaped member arranged on the wall is obtained.

  According to the molding method of the present invention, since the corners of the columnar material are arranged on the bottom wall, the corners and burrs generated in the vicinity of the corners are located on the bottom wall. For this reason, generation | occurrence | production of the wrinkle of the cylindrical part of a cup-shaped member can be avoided.

  Using a pre-forming forging die equipped with a die and an upsetting punch having a recess at the punch end face, the columnar material is placed with the corners of the cylindrical material arranged inside the recessed portion of the upsetting punch. A disk-shaped preform having a convex portion formed on the upper surface by compression in the axial direction can be formed.

  When such a preforming forging die is used, the preform is formed with a convex portion on the upper surface thereof, and the corner portion of the material is positioned at the convex corner portion.

  Using a shaft-forming forging die, compressing the cylindrical material in the axial direction to form a pre-formed body on which the protrusion for forming the shaft portion is formed, and then setting the die and the punch end face with a recess Using a pre-forming forging die provided with a punch for use, with the corners of the pre-formed body placed inside the recesses of the upsetting punch, the pre-formed body is compressed in the axial direction into the recesses. You may shape | mold the preforming body which has the convex part formed correspondingly on the upper surface.

  Also, using a forging die for molding provided with a die and a molding punch having a recess at the punch end surface, the convex portion of the preform formed by the forging die for preliminary molding is arranged inside the concave portion of the molding punch. In this state, the preform can be compressed in the axial direction, and the outer peripheral side material can be extruded in the direction opposite to the compression direction to obtain a cup-shaped member.

  If this forging die for molding is used, the cylindrical portion of the cup-shaped member is formed by compressing the preform in the axial direction and extruding the outer peripheral side material in the direction opposite to the compression direction. At this time, in this cylindrical portion, it is possible to avoid the corner portion of the columnar material from being positioned.

  Even if the outer peripheral rising surface of the concave portion of the punch constitutes a tapered surface that spreads from the bottom side toward the opening side, or constitutes a rounded surface that spreads from the bottom side toward the opening side, You may comprise by the taper surface and rounded surface which spread toward the opening side from a bottom side.

  Using a forging die for the bottom wall provided with a die and a molding punch, the bottom wall of the cup-shaped member is compressed in the axial direction from the inner surface side, and is formed on the inner surface of the bottom wall formed by the forging die for molding. May be a flat surface.

  If the forging die for bottom walls is used, a product (cup-shaped member) having a flat bottom wall inner surface can be formed. Moreover, it is preferable that the die for the bottom wall forging die is provided with a concave portion that serves as a material escape when the convex portion on the inner surface of the bottom wall is a flat surface.

  In the present invention, generation of wrinkles in the cylindrical portion of the cup-shaped member can be avoided. For this reason, it is not necessary to perform chamfering, shot blasting, and the like on the columnar material that has been required in the past, and it is possible to reduce production costs and improve productivity. In addition, since it is not necessary to perform chamfering, shot blasting, and the like, molding can be performed using equipment for cutting in a molding machine such as a former, and productivity can be further improved.

  If a forging die for preforming provided with a die and an upsetting punch having a recess at the punch end surface is used, the preform is formed with a convex portion on its upper surface, The corner portion is located at the bottom, and it is possible to prevent wrinkles from being stably generated in the cylindrical portion of the cup-shaped member by subsequent molding with a forging die for molding.

  A cup-shaped member with a shaft portion can be formed by using a forging die for forming a shaft portion and molding a pre-formed body on which a projection for forming a shaft portion is formed.

  If a forging die for molding provided with a die and a molding punch having a recess at the punch end face is used, it is possible to avoid the corner portion of the columnar material being located in the cylindrical portion. Do not cause wrinkles stably in the cylindrical part.

  If a forging die for a bottom wall provided with a die and a molding punch is used, a product (cup-shaped member) having a flat bottom wall inner surface can be molded, and the degree of freedom in designing the molded cup-shaped member Improvements can be made.

  If the bottom wall forging die is provided with a recess to escape the material when the convex portion of the bottom wall inner surface is a flat surface, the material will escape to the recess during molding, The convex part of the inner surface of the bottom wall can be made a flat surface stably.

The preforming forging die used in the first forming method of the present invention is shown, (a) is a simplified view of a state in which a cylindrical preform material is set in the preforming forging die, and (b) is a preformed body. It is a schematic diagram of the state which is forming. The forging die for shaping | molding used for the 1st shaping | molding method of this invention is shown, (a) is the simplified figure of the state which set the preform to this forging die for shaping | molding, (b) shape | molds a cup-shaped member. FIG. The bottom wall forging die used for the 1st shaping | molding method of this invention is shown, (a) is the simplified figure of the state which set the cup-shaped member to this forging die for bottom walls, (b) is the bottom wall inner surface. It is a simplification figure of the state which shape | molds the cup-shaped member made into the flat surface. The shaft part forging die used for the 2nd shaping | molding method of this invention is shown, (a) is the simplification figure of the state which set the preform to this shaft part forging die, (b) is preliminary It is a simplification figure of the state which is forming a forming object. The forging die for preforming used for the 2nd shaping | molding method of this invention is shown, (a) is the simplified figure of the state which set the preformed preform for this forging die for preforming, (b) is a preforming body. It is a schematic diagram of the state which is forming. The forging die for shaping | molding used for the 2nd shaping | molding method of this invention is shown, (a) is the simplified figure of the state which set the preform to this forging die for shaping | molding, (b) shape | molds a cup-shaped member. FIG. FIG. 2A is a cross-sectional view of a main part in which the outer peripheral rising surface of the concave portion is a tapered surface spreading from the bottom side toward the opening side, and FIG. It is principal part sectional drawing which is a rounded surface which spreads toward the side. The forging die for preforming used for the conventional forming method is shown, (a) is a simplified view of a state in which a cylindrical preform material is set in this forging die for preforming, and (b) is a preformed body formed by molding. FIG. The forging die for shaping | molding used for the conventional shaping | molding method is shown, (a) is the simple figure of the state which set the preforming body to this forging die for shaping | molding, (b) is the state which shape | molds the cup-shaped member. It is a simplified diagram. A columnar material is shown, (a) is a sectional view in a state where burrs are formed at corners, and (b) is a sectional view in a state where burrs are formed at other corners.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. In the molding method according to the present invention, a preformed body S2 is molded with a preforming forging die 20 as shown in FIGS. 1A and 1B, and then a molding forging die 22 as shown in FIG. The bottomed cylindrical cup-shaped member S is formed. As shown in FIG. 2B, the cup-shaped member S has a cylindrical portion 23 and a bottom wall 24 that closes the lower opening of the cylindrical portion 23. The material supplied to the preforming forging die 20 is a columnar material S1 obtained by cutting a bar material to have a predetermined axial length by sawing or shearing (see FIG. 1A). It is.

  As shown in FIGS. 1A and 1B, the pre-form forging die 20 includes an upsetting punch 25 and a die 26. The upsetting punch 25 has a recess 27 formed in the lower end surface 25a thereof. In this case, as shown in FIG. 1A, the outer diameter D1 of the columnar material S1 is set slightly smaller than the inner diameter d of the recess 27 of the upsetting punch 25.

  For this reason, the preforming body S2 (see FIG. 1B) is molded by the forging die 20 for preforming, as shown in FIG. 1A, the cylindrical material S1 is set on the die 26 (the mounting of the die 26). As a state of being placed on the placement surface 26a), the upsetting punch 25 is lowered. Accordingly, the columnar material S1 is compressed in the axial direction in a state in which the corner portion 28 of the columnar material S1 is disposed inside the recess 27 of the upsetting punch 25, and is formed corresponding to the recess 27. A disk-shaped preform S2 having the portion 30 on the upper surface is formed. In the set state, the axis O of the concave portion 27 of the upsetting punch 25 is arranged on the axial center line (center line L1) of the columnar material S1.

  As shown in FIGS. 2A and 2B, the forging die 22 for forming includes a forming punch 31 and a die 32. The molding punch 31 has a recess 33 on the punch end surface 31a. In this case, rounded chamfered portions 34 are provided at the corners on the punch end surface 31 a side of the forming punch 31. The die 32 has a bottom wall 32b and a peripheral wall 32a rising from the outer peripheral edge of the bottom wall 32b.

  For this reason, the molded body S is molded by the forging die 22 for molding, as shown in FIG. 2A, with the preform S2 set on the die 32 (in a state of being housed inside the die 32), the molding punch 31. Will be lowered. Accordingly, the preform S2 is compressed in the axial direction in a state where the convex portion 30 of the preform S2 is disposed inside the recess 33 of the molding punch 31. At this time, the axis (center line) L2 of the preform S2 and the center line O1 of the forming punch 31 are made to coincide. Moreover, the outer diameter dimension of the punch 31 is set smaller than the inner diameter dimension of the die 32, and a gap is formed between the outer peripheral surface 35 of the molding punch 31 and the inner peripheral surface 36 of the peripheral wall 32 a of the die 32 as will be described later. 38 (see FIG. 2B) must be generated.

  When the preform S <b> 2 is compressed in the axial direction by the molding punch 31, as shown in FIG. 2B, the outer peripheral side material is extruded in the direction opposite to the compression direction, and the cup-shaped member S is molded. That is, when the preform S2 is compressed in the axial direction by the molding punch 31, the material enters the gap 38 between the outer peripheral surface 35 of the molding punch 31 and the inner peripheral surface 36 of the peripheral wall 32a of the die 32. Thus, the cylindrical portion 23 of the cup-shaped member S is formed. At this time, since the corner portion 28 of the cylindrical material S1 is disposed at the corner portion of the convex portion 30 of the preform S2, the corner portion 28 of the columnar material S1 is placed on the bottom wall 24 of the cup-shaped member S. Will be placed.

  Further, since the concave end 33 is formed on the punch end surface 31 a of the molding punch 31, the convex portion 37 is formed on the inner surface side of the bottom wall 24 of the cup-shaped member S. The molding of the cup-shaped member S may be completed in this step, but the convex portion 37 may be eliminated on the inner surface side of the bottom wall 24 using a bottom wall forging die 40 shown in FIG.

  The bottom wall forging die 40 includes a forming punch 41 and a die 42. The molding punch 41 has a flat end surface 41a. The die 42 has a bottom wall 42b and a peripheral wall 42a rising from the outer peripheral edge of the bottom wall 42b. A recess 44 is formed in the inner surface 43 of the bottom wall 42b.

  For this reason, as shown in FIG. 3A, the cup-shaped member S is set in the die 42 of the forging die 40 for the bottom wall, the molding punch 41 is lowered, and the molding punch 41 lowers the bottom wall. If 24 is pressed along the axial direction, the convex portion 37 of the bottom wall 24 is crushed and the inner surface of the bottom wall 24 becomes a flat surface. At this time, by pressing the convex portion 37, the material on the bottom surface (outer surface) side of the bottom wall 24 flows into the concave portion 44, and the convex portion 45 is formed on the bottom surface (outer surface) side of the bottom wall 24. . For this reason, it is preferable that the capacity of the concave portion 44 corresponds to the volume into which the convex portion 37 is pushed.

  Further, when the forming punch 41 is lowered, the axis L of the cup-shaped member S and the axis O2 of the punch 41 are made to coincide. The outer diameter dimension of the punch 41 is set to be the same as the inner diameter dimension of the cup-shaped member S or smaller than the inner diameter dimension of the cup-shaped member S, and the molded cup 41 is lowered when the molding punch 41 is lowered. It is set so as not to affect the peripheral wall 23 of the shaped member S.

  Thus, if the bottom wall forging die 40 is used, a product (cup-shaped member) having a flat bottom wall inner surface can be formed, and the degree of freedom in designing the molded cup-shaped member can be improved. Can do.

  Next, FIGS. 4 to 6 show a molding process of the cup-shaped member Sa with a shaft portion. That is, as shown in FIG. 6B, the shaft-shaped cup-shaped member Sa includes a cup-shaped main body 50 and a shaft 51 that protrudes from the bottom wall of the main body 50. The main body 50 includes a bottom wall 53b and a peripheral wall 53a that rises from the outer peripheral edge of the bottom wall 53b.

  The molding process of the cup-shaped member Sa with the shaft portion includes a process of molding a preformed preform as shown in FIGS. 4 (a) and 4 (b), and a preformed body as shown in FIGS. 5 (a) and 5 (b). A step of forming, and a step of forming a formed body as shown in FIGS.

  As the pre-formed body, a shaft portion forging die 54 as shown in FIGS. 4A and 4B is used. The shaft portion forging die includes a punch 55 and a die 56. The punch 55 has a recess 57 on the punch surface. The rising surface 57a of the recess 57 is a tapered surface that widens from the bottom side toward the opening side.

  The die 56 includes a large-diameter main body portion 58a, a small-diameter portion 58b, a round portion 58c provided on the lower end side of the main body portion 58a and having a small diameter toward the small-diameter portion 58b, and a lower end side of the round portion 58c. A molding chamber 58 is provided which is provided with a tapered portion 58d which is provided and is reduced in diameter toward the small diameter portion 58b. A knockout pin 59 is fitted into the small diameter portion 58 b of the die 56.

  For this reason, in the step of forming the preformed preform, first, the columnar material S1 is set in the forming chamber 58 of the die 56 as shown in FIG. At this time, the columnar material S1 is received by the round portion 58c, and the axis (center line) L1 of the columnar material S1, the center line of the molding chamber 58 of the die 56, and the axis (center line) of the punch 55. It is assumed that O3 matches. Further, the inner diameter D3 of the main body 58a and the outer diameter d3 of the punch 55 are set to be substantially the same. That is, as shown in FIG. 4B, when the cylindrical material S1 is compressed by the punch 55, the body portion 58a of the punch 55 can be fitted, and the outer peripheral surface of the punch 55 and the body portion 58a It is a grade which the raw material 1 does not protrude between.

  When the punch 55 is lowered from the state shown in FIG. 4A, the upper corner portion 28 of the cylindrical material S1 first comes into contact with the rising surface 57a of the recess 57. Thereafter, when the punch 55 is further processed, as shown in FIG. 4B, the lower portion of the punch 55 enters the main body portion 58a of the die 56, and the material S1 flows into the rounded portion 58c and the tapered portion 58d. In the main body portion 58a, the material S1 has a large diameter, and the pre-formed body S3 is formed. For this reason, the preformed preform S3 includes a large-diameter head portion 60, a tapered portion 61 that gradually decreases in diameter toward the lower end, and a rounded portion 62 between the tapered portion 61 and the head portion 60. A chamfered portion 60 a is formed on the outer peripheral portion of the upper surface of the head portion 60 by the rising surface 57 a of the punch 55.

  Even during the molding of the preformed preform S3, the corner portion 28 of the material S1 is disposed inside the concave portion 57 of the punch 55, so that the corner portion 28 of the material S1 is placed in the preformed preform S3. The chamfered portion 60a of the head portion 60 is located.

  For forming the preform S2, a forging die 64 for preforming as shown in FIGS. 5A and 5B is used. The preforming forging die 64 includes a punch 65 and a die 66. The punch 65 has a recess 67 in its punch surface 65a. The rising surface 67a of the recess 67 is a tapered surface that widens from the bottom side toward the opening side.

  The die 66 includes a molding chamber 68 composed of a main body portion 68a having a large diameter and a small diameter portion 68b. A corner portion between the inner diameter surface 70 and the bottom surface 71 of the main body portion 68 a is a rounded portion 72, and a corner portion between the bottom surface 71 and the small diameter portion 68 b is a rounded portion 73. A knockout pin 69 is fitted into the small diameter portion 68 b of the die 66. The outer diameter dimension d4 of the punch 65 and the inner diameter dimension D4 of the large diameter portion 68a of the die 66 are set to be substantially the same. Here, as shown in FIG. 5 (b), “substantially the same” means that when the pre-formed body S 3 is compressed by the punch 65, the body portion 68 a of the punch 65 can be fitted, and the punch 65 It is a grade which a raw material does not protrude between an outer peripheral surface and the main-body part 58a.

  For this reason, in the step of molding the preform S2, first, the preformed preform S3 is set in the molding chamber 68 of the die 66 as shown in FIG. At this time, the pre-formed body S3 is received by the knockout pin 69, and the space between the taper portion 61 and the round portion 62 corresponds to the round portion 73. In this state, the axis (center line) L4 of the preformed preform S3, the center line of the molding chamber 68 of the die 66, and the axis (center line) O4 of the punch 65 are made to coincide.

  In this case, when the punch 65 is lowered, the upper chamfered portion 60 a of the preformed preform S 3 first comes into contact with the rising surface 67 a of the concave portion 67. Thereafter, as the punch 65 is further processed, as shown in FIG. 5B, the lower portion of the punch 65 enters the main body 68a of the die 66, and the material flows into the small diameter portion 68b. The material is enlarged in diameter, and the preform S2 is formed. Therefore, the preform S <b> 2 includes a large-diameter disk part 90 and a shaft part 91 that protrudes from the center of the lower surface of the disk part 90. A convex portion 92 is formed on the upper surface of the disk portion 90 corresponding to the concave portion 67 of the punch 65. At this time, a chamfered portion 92 a (see FIG. 6A) is formed at the corner portion of the convex portion 92 at the rising surface 67 a of the concave portion 67 of the punch 65.

  Even when the preform S2 is molded, the chamfered portion 60 of the preformed preform S3 corresponds to the rising surface 67a of the recess 67 of the punch 65, so that the corner portion 28 of the material S1 is convex to the convex of the preform S2. It will be located in the chamfered part 92a of the part 92.

  In the step of molding the molded body, a forging die 74 for molding shown in FIGS. 6A and 6B is used. The forming forging die 74 includes a punch 75 and a die 76. The punch 75 has a recess 77 on the punch surface. The rising surface 77a of the recess 77 is a tapered surface that widens from the bottom side toward the opening side.

  The die 76 includes a molding chamber 78 composed of a large-diameter main body portion 78a and a small-diameter portion 78b. A corner portion between the inner diameter surface 80 and the bottom surface 81 of the main body portion 78 a is a rounded portion 82, and a corner portion between the bottom surface 81 and the small diameter portion 78 b is a rounded portion 83. A knockout pin 79 is fitted into the small diameter portion 78 b of the die 76.

  At this time, the axis (center line) L5 of the preform S2 and the center line O5 of the punch 75 are matched. The outer diameter of the punch 75 is set to be smaller than the inner diameter of the main body 78a of the large diameter of the die 76. As will be described later, the outer peripheral surface 86 of the molding punch 75 and the main body of the large diameter of the die 76. A gap 88 (see FIG. 6B) needs to be generated between the inner peripheral surface 87 of 78a.

  For this reason, in the step of molding the molded body S, first, as shown in FIG. 6A, the preformed body S2 is set in the molding chamber 78 of the die 76. At this time, the preform S2 is received by the knockout pin 79, and the disk portion 90 is fitted to the main body portion 78a of the molding chamber 78, and the shaft portion 91 is fitted to the small diameter portion 78b of the molding chamber 78. It becomes a state to do.

  In this state, the axis (center line) O5 of the preform S2 and the center line (center line of the molding punch 75) L5 of the molding chamber 78 of the die 76 are made to coincide with each other. In this state, as shown in FIG. 6B, if the molding punch 75 is lowered and the upper surface of the preform S2 is pressed along the axial direction with this molding punch 75, the material on the outer peripheral side is compressed. The cup-shaped member S (Sa) with the shaft portion is molded by being extruded in the direction opposite to the direction. At this time, the convex portion 92 on the upper surface of the preform S2 is set so as to be positioned inside the concave portion 67 of the molding punch 75. In the forging die 74 for molding shown in FIG. 6, the convex portion 85 is formed by the concave portion 77 of the molding punch 75 on the inner surface of the bottom wall 53 b of the cup-shaped member S with a shaft portion.

  Also in the molding of the molded body Sa, the chamfered portion 92a of the convex portion 92 of the preform S2 corresponds to the rising surface 77a of the concave portion 77 of the punch 75, so that the corner portion 28 of the material S1 is formed on the molded body Sa. It will be located in the chamfer 85a of the convex part 85. FIG. That is, even in this molding method, the corner portion 28 of the material S1 is positioned on the bottom wall 53b of the molded body Sa.

  According to the molding method of the present invention, since the corner portion 28 of the cylindrical material S1 is disposed on the bottom wall 24, the corner portion 28 and burrs generated in the vicinity of the corner portion are located on the bottom wall 24. become. For this reason, generation | occurrence | production of the wrinkle of the cylindrical part 23 of the cup-shaped member S can be avoided. Accordingly, it is no longer necessary to perform chamfering, shot blasting, and the like on the columnar material that has been required in the past, and it is possible to reduce production costs and improve productivity. In addition, since it is not necessary to perform chamfering, shot blasting, and the like, molding can be performed using equipment for cutting in a molding machine such as a former, and productivity can be further improved.

  If the forging die 20 for preforming provided with the die 26 and the upsetting punch 25 having the recessed portion 27 on the punch end surface 25a is used, the projection 30 is formed on the upper surface of the preform S2. In addition, the corners are positioned in the convex portion 30, and it is possible to prevent wrinkles from being stably generated in the cylindrical portion 23 of the cup-shaped member S by the subsequent molding with the forging die 22 for molding.

  By using the shaft-forming forging die 54 and molding the pre-formed body S3 on which the shaft-constituting projection 54 is formed, the cup-shaped member Sa with the shaft can be formed.

  If the forging die 22 for molding provided with the die 32 and the molding punch 31 having the recess 33 at the punch end face is used, the corner portion 28 of the columnar material S1 is avoided from being positioned in the cylindrical portion 23. Thus, wrinkles are not stably generated in the cylindrical portion 23 of the cup-shaped member S.

  By using a bottom wall forging die 40 having a die 42 and a molding punch 41, a product (cup-shaped member) having a flat bottom wall inner surface can be formed. The degree of design freedom can be improved.

  If the die 42 of the forging die 40 for the bottom wall is provided with a recess 44 that escapes the material when the convex portion on the inner surface of the bottom wall is a flat surface, the material escapes into the recess 44 during molding. Thus, the convex portion 37 on the inner surface of the bottom wall can be stably made flat.

  Incidentally, the outer peripheral rising surface 27a of the concave portion 27 of the punch 25 of the preforming forging die 20 shown in FIG. 1 and the outer peripheral rising surface 33a of the concave portion 33 of the forming punch 31 shown in FIG. 7 is a flat surface extending in parallel with the direction, but a tapered surface as shown in FIG. 7A (a tapered surface extending from the bottom side toward the opening side), that is, the concave portion 57 of the punch 55 shown in FIG. The outer peripheral rising surface 57a, the outer peripheral rising surface 67a of the concave portion 67 of the punch 65 shown in FIG. 5, the outer peripheral rising surface 77a of the concave portion 77 of the punch 75 shown in FIG. In FIG. 7A, the inclination angle θ is about 40 °, but the inclination angle can be arbitrarily set within a range that does not become an acute angle.

  Further, as the outer peripheral rising surfaces 27a and 33a, as shown in FIG. 7B, they may be rounded surfaces (rounded surfaces spreading from the bottom side toward the opening side). Further, the outer peripheral rising surfaces 27a and 33a may have a composite shape including a tapered surface and a rounded surface.

  As described above, the embodiment of the present invention has been described. However, the present invention is not limited to the above-described embodiment, and various modifications are possible, and even “hot forging” is “cold forging”. Alternatively, “warm forging” may be used. Moreover, it can respond to the metal which can be forged, such as a nonferrous metal, stainless steel, alloy steel, and carbon steel as a metal raw material. The cup-shaped member as a product can be applied to an outer joint member (outer ring) of a constant velocity universal joint, a bottomed internal gear (bottomed internal gear), and the like.

  Further, the outer peripheral rising surfaces 57a, 67a, 77a of the punches 55, 65, 75 other than the punches 25, 31 are tapered surfaces in the illustrated example, but they extend from the rounded surface (from the bottom side toward the opening side). A rounded surface), or a composite shape composed of a tapered surface and a rounded surface.

20 Pre-forming forging die 22 Molding forging die 24 Bottom wall 25 Upsetting punch 25a Lower end surface 26, 32, 42, 56, 66, 76 Die 27, 33, 44, 57, 77 Recessed portion 27a Outer peripheral rising surface 28 angle Portions 30, 37 Convex portions 31, 41, 75 Molding punch 31a Punch end surface 33a Outer peripheral rising surface 40 Bottom wall forging die 41a Punch end surface 54 Shaft forming forging die 55, 65 Punch 57a Outer peripheral rising surface 64 Preliminary forging die 67 Concave part 67a Peripheral rising surface 74 Forging die for molding 77a Peripheral rising surface S Cup-shaped member (molded body)
S1 Cylindrical material S2 Pre-formed body S3 Pre-formed body Sa Cup-shaped member with shaft

Claims (9)

This is a molding method in which a cylindrical shaped material formed by cutting a rod is used to form a preform with a forging die for preforming, and then a bottomed cylindrical cup-shaped member is obtained with the forging die for molding. And
A cup-shaped member in which the preform is compressed in the axial direction with a forging die for molding, the outer peripheral side material is extruded in the direction opposite to the compression direction, and the corners of the columnar material are arranged on the bottom wall. A molding method characterized by obtaining.   Using a pre-forming forging die equipped with a die and an upsetting punch having a recess at the punch end face, the columnar material is placed with the corners of the cylindrical material arranged inside the recessed portion of the upsetting punch. 2. The molding method according to claim 1, wherein a disk-shaped preform having a convex portion formed on the upper surface by compression in the axial direction is formed.   Using a shaft-forming forging die, compressing the cylindrical material in the axial direction to form a pre-formed body on which the protrusion for forming the shaft portion is formed, and then setting the die and the punch end face with a recess Using a pre-forming forging die provided with a punch for use, with the corners of the pre-formed body placed inside the recesses of the upsetting punch, the pre-formed body is compressed in the axial direction into the recesses. The molding method according to claim 1, wherein a preform having a convex portion formed on the upper surface is molded.   Using a forging die for molding provided with a die and a molding punch having a recess on the punch end surface, a state in which the convex portion of the preform formed by the forging die for preliminary molding is arranged inside the concave portion of the molding punch The molding method according to claim 2 or 3, wherein the preform is compressed in the axial direction, and the outer peripheral side material is extruded in a direction opposite to the compression direction to obtain a cup-shaped member.   The molding method according to any one of claims 2 to 4, wherein an outer peripheral rising surface of the concave portion of the punch constitutes a tapered surface extending from the bottom side toward the opening side.   The molding method according to any one of claims 2 to 4, wherein the outer peripheral rising surface of the concave portion of the punch constitutes a rounded surface that spreads from the bottom side toward the opening side.   The molding method according to any one of claims 2 to 4, wherein an outer peripheral rising surface of the concave portion of the punch is configured by a tapered surface and a rounded surface that spread from the bottom side toward the opening side. .   Using a forging die for the bottom wall provided with a die and a molding punch, the bottom wall of the cup-shaped member is compressed in the axial direction from the inner surface side, and is formed on the inner surface of the bottom wall formed by the forging die for molding. The molding method according to claim 2, wherein the surface is a flat surface.   The molding method according to claim 8, wherein the bottom wall forging die includes a recess that serves as a material escape when the convex portion on the inner surface of the bottom wall is a flat surface.

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