JP5099669B2 - Forming method of forged products - Google Patents

Description

The present invention relates to a molding how forged product having a precision forging unit, the through hole in the axial center portion to the outer periphery.

  Conventionally, when an intermediate forged product having a tooth profile on the outer periphery is formed by forging from a pre-forged product, a forging product forming device in which the volume of the engraving space formed by the fixed die and the movable die is substantially equal to the volume of the intermediate forged product is used. After the pre-forged product is closed in the die-sculpting space, the entire pre-forged product is pressed by the moving die in this die-sculpting space, so that the meat of the axial center part of the pre-forged product is moved in the outer circumferential direction. There is known a technique for forming an intermediate forged product having a tooth profile formed thereon. The intermediate forged product is further punched out to form a forged product in which a tooth shape is formed on the outer periphery and a through hole is formed in the axial center (see Patent Document 1).

In addition, as a different forging method when forging an intermediate forging product having a tooth profile on the outer periphery, the gap between the fixed die and the movable die is not closed without closing the engraving space formed by the fixed die and the movable die. Using the forming device for the forged product to be formed, the meat of the axial center part of the pre-forged product is moved in the outer peripheral direction by pressing it with the movable die in the mold engraving space that does not block the entire pre-forged product, and the tooth profile on the outer periphery In addition, a technique for forming an intermediate forged product formed with burrs is also known. This intermediate forged product is formed by punching a shaft center part and a burr and forming a forged product having a tooth shape on the outer periphery and a through hole formed on the shaft center part (see Patent Document 2).
Japanese Patent Laid-Open No. 9-108771 Japanese Patent No. 2884044

  However, in the closed mold carving space, the volume of the closed mold carving space and the volume of the intermediate forging product to be formed are set to be approximately equal. The gap in which the meat of the forged product flows is narrowed, and the flow of the meat is suppressed by a complicated shape such as a tooth mold formed on the die, so that the corner of the outer periphery of the obtained intermediate forged product is There was a problem of lack of meat. Further, when the entire pre-forged product is pressed by a movable die, there is a problem that a forging device requires a large load in the case of a product having a large pressing area (see Patent Document 1).

  Therefore, as in Patent Document 2, a gap is formed between the fixed die and the movable die so as not to cause a lack of thickness at the outer peripheral corner of the intermediate forged product, and a burr is formed on the outer periphery of the intermediate forged product. In the forging method in which the pre-forged product is flowed until it is done, there is an effect that the outer peripheral shape necessary for the intermediate forged product can be obtained, but since burrs are formed on the outer periphery, deburring is necessary in the subsequent process. There was a problem.

Therefore, the present invention has been made in view of the above circumstances, there is no lack of thickness for the precision forged part formed on the outer periphery of the forged product, and the load of the forging device is reduced. and to provide a molding how forged products omit deburring.

Method of forming a forged product of the present invention, the substantially disk-shaped preliminary forging, has a through hole in the axial center portion, in the molding method for molding a forged product having a precision forged part on the outer periphery, a substantially disc-shaped material To form a pre-forged product that has a first positioning projection on the shaft center, and a movable die that forges the pre-forged product and a fixed die are in contact with each other to form a die-sculpting space with a closed outer periphery. Then, the precision forged part is formed on the outer periphery of the preliminary forged product by the movable die and the fixed die, and the first positioning convex portion is deformed on the axial center portion of the preliminary forged product, so that both the movable die and the fixed die are used. A precision forged portion forming step for obtaining an intermediate forged product in which a bowl-shaped surplus portion that is in a non-contact state is formed, and a piercing forming step for punching the surplus portion of the intermediate forged product to form a through hole This is the first feature.

  The method for forming a forged product according to the present invention is characterized in that the precision forged portion has a tooth profile.

According to the method for forming a forged product of the first feature of the present invention, from a substantially disk-shaped pre-forged product, in a method for forming a forged product having a through hole in the axial center portion and a precision forged portion on the outer periphery, The outer periphery is closed by pressing a substantially disk-shaped material and forming a pre-forged product having a first positioning convex portion at the axial center, and a movable die forging the pre-forged product and a fixed die abut. forming a die-sinking space, the outer periphery of the preliminary forging, the precision forging unit by mobile and fixed is formed, the axial center of the pre-forging, with the first positioning projection is deformed, mobile A precision forged part forming step for obtaining an intermediate forged product in which a bowl-shaped surplus part that is in a non-contact state is formed on both the stationary mold and the piercing for punching the surplus part of the intermediate forged product to form a through hole The outer periphery of the forged product by a mold-sculpting space whose outer periphery is closed. Without burrs, it is possible to omit the deburring process. In addition, the bowl-shaped surplus portion formed in the axial center portion of the pre-forged product is in a non-contact state with both the movable die and the fixed die, so the meat of the precision forged portion formed on the outer periphery is in the axial portion. It flows into the surplus portion to be molded, and the flow of the meat in the precision forging portion is promoted, so that no thinning occurs in the precision forging portion on the outer periphery of the intermediate forging product. Moreover, since the bowl-shaped surplus part to be molded is in a non-contact state with both the movable mold and the fixed mold, the molding load of the forging device can be reduced.

  According to the method for forming a forged product according to the second feature of the present invention, the precision forged part has a tooth profile, and therefore it is possible to prevent a lack of thickness from occurring in the tooth profile.

  Embodiments of the present invention will be described below with reference to FIGS. FIG. 1 is a cross-sectional plan view showing a method for forming a forged product having a precision forged portion and a through hole according to the present invention. FIG. 2 is a partial cross-sectional plan view showing a molding process for molding the pre-forged product of the present invention. FIG. 3 is a partial cross-sectional plan view showing a forming process for forming the intermediate forged product of the present invention. FIG. 4 is a partial cross-sectional plan view showing a molding process for molding a forged product having a precision forged portion and a through hole according to the present invention.

  As shown in FIG. 1A, the forging product W4 is formed by first cutting a wire into a required length to form a cylindrical cutting material W0, and then, FIG. In this manner, the disc-shaped material W1 is formed by pressing the cutting material W0 in the axial direction. Thereafter, a pre-forged product having a disk-shaped material W1 pressed in the axial direction and having a preliminary tooth profile portion 8 as a basis of the tooth profile 2 on the outer periphery and a first positioning convex portion 7 as a base of the surplus portion 3 at the axial center. W2 is formed ((c) in FIG. 1). Then, the preliminary forged product W2 is further pressed to form an intermediate forged product W3 in which a tooth shape as the precision forged portion 2 and a bowl-shaped surplus portion 3 are formed on the outer periphery. The intermediate forged product W3 is provided with a through-hole forming guide recess 10 for guiding a piercing punch 67 of a piercing device 61 described later at one end in the axial direction. Finally, the surplus portion 3 of the intermediate forged product W3 is punched out to form a forged product W4 having a through hole 4 in the axial center portion.

  Next, the first forging device 21, the second forging device 41, and the piercing device 61 that sequentially form the forged product W4 from the disk-shaped material W1 will be described with reference to FIGS.

  As shown in FIG. 2, the forging device 21 includes a fixed die 31 and a movable die 22. The fixed die 31 is disposed on the inner periphery side of the die 36 that forms the die-sculpting space 37 into which the disk-shaped material W1 of FIG. 1 is put, and the cylindrical knockout 32 that similarly forms the die-sculpting space 37. A knockout pin 33 that allows the knockout 32 to move forward and backward, a cylindrical first support die 34 that supports the knockout 32 so as to advance and retract, and a cylindrical second support die 35 that supports the knockout pin 33 so as to advance and retract. . In addition, the mold engraving space 37 formed in the die 36 has a first step portion 36b and a second step portion from the counter-moving mold side to the moving mold side so that a convex portion is formed in the obtained preliminary forged product W2. 36c and the third step portion 36d are sequentially formed.

  The movable die 22 includes a punch 23 that presses the disk-shaped material W1 and a pin 24 that is disposed at the axial center of the punch 23. The pin 24 is urged toward the anti-fixed die by a spring 25. Yes. And the inner peripheral part 37a of the die-sculpting space 37 of the die | dye 35 and the outer peripheral part 23a of the punch 23 contact | abut, and the closed die-sculpture space 37 is formed.

  Next, a second forging device 41 that forms an intermediate forging product W3 by forming a tooth profile as the precision forging portion 2 on the outer periphery of the preliminary forging product W2 formed by the first forging device 21 will be described with reference to FIG. The second forging device 41 includes a fixed mold 51 and a movable mold 42. The fixed die 51 is arranged on the inner peripheral side of the die 55 that forms a part of the die carving space 59, and similarly, a knockout 52 that forms a part of the die carving space 59, and a knockout pin 53 that allows the knockout 52 to move forward and backward. The first support die 54 has a cylindrical shape that supports the knockout 52 so that the knockout pin 52 can move forward and backward, and the second support die 48 has a cylindrical shape that supports the knockout pin 53 so that it can move forward and backward. On the inner surface of the die 55, there is a tooth forming portion 56 that forms a tooth shape.

  The movable die 42 includes an outer punch 46 that presses the outer periphery of the preliminary forged product W2, an inner punch 47 that is disposed on the inner periphery of the outer punch 46 and that forms the through-hole forming guide recess 10 of the intermediate forged product W3, and the inner punch 47. The pin 44 is disposed at the axial center of the pin 44, and the pin 44 is urged toward the anti-fixed mold side by a spring 45. A closed engraving space 59 is formed by contacting the inner peripheral portion 55a of the die engraving space 59 of the die 55 with the outer peripheral portion 46a of the outer punch 46. The closed engraving space 59 is between the outer punch 46 and the die 55, between the first space 57 having the same shape as the precision forged portion 2 on the outer periphery of the intermediate forged product W3, and between the inner punch 47 and the knockout 52, It has the surplus part 3 formed in the axial center part of the intermediate forging product W3, and the 2nd space part 58 from which the inner punch 47 and the knockout 52 will be in a non-contact state.

  Next, the piercing device 61 for punching the surplus portion 3 of the intermediate forged product W3 formed by the second forging device 41 will be described with reference to FIG. The piercing device 61 includes a fixed die 71 and a moving die 62. The fixed die 71 includes a first support die 74 that positions and supports the outer periphery of the intermediate forged product W3 on the outer periphery, and a second support die 75 that is disposed on the inner peripheral side of the first support die 74 and supports the intermediate forged product W3. . In the inner periphery of the second support die 75, a surplus portion discharge port 76 for discharging the surplus portion 3 punched out of the intermediate forged product W3 is formed.

  The movable die 62 includes a pierce stripper 66 that presses the intermediate forged product W3 against the fixed die 71, and a pierce punch 67 that is disposed inside the pierce stripper 66 and that forms the through hole 4 in the intermediate forged product W3. Is biased toward the fixed mold by a spring 65.

  Subsequently, a process of forming the forged product W4 from the disk-shaped material W1 will be described with reference to FIGS.

  When the preliminary forging product W2 is formed from the disk-shaped material W1 by the first forging device 21, the disk-shaped material W1 is moved from the disk-shaped material W1 to the outer stage 6 at the axial end by the first stage of the die 36. It positions by making it contact | abut to the part 36b, and mounts on the die | dye 36. FIG. Subsequently, as shown in FIG. 2, the movable die 22 is lowered and the disc-shaped material W <b> 1 is pressed, so that the meat of the disc-shaped material W <b> 1 flows in the outer circumferential direction in the closed engraving space 37. A preliminary positioning portion 8, a first positioning convex portion 7 in which the outer end portion 6 of the material W1 is deformed in the axial center portion, and a second positioning convex portion 9 between the preliminary tooth shape portion 8 and the first positioning convex portion 7. The pre-forged product W2 is formed. When the formation of the preliminary forged product W2 is completed, the movable die 22 is retracted upward. Thereafter, the knockout pin 33 is moved to the movable die 22 side by the knockout pin 33, and the preliminary forged product W2 is taken out from the die 35.

  Next, a process of forming the intermediate forged product W3 from the preliminary forged product W2 by the second forging device 41 will be described with reference to FIG. The pre-forged product W <b> 2 is placed on the fixed die 51 by placing the pre-forged product W <b> 2 so that the second positioning convex portion 9 fits into the opening 52 a of the die-sculpting space 59 of the knockout 52. Subsequently, when the movable die 42 is lowered and the outer periphery of the preliminary forged product W2 is pressed, the preliminary tooth shape portion 8 of the preliminary forged product W2 has the same shape as the first space portion 57 formed between the outer punch 46 and the die 55. Transforms into At this time, in the second space 58 formed between the inner punch 47 and the knockout 52, the first positioning convex portion 7 of the preliminary forged product W2 is deformed to form the surplus portion 3. The surplus portion 3 is not in contact with at least a part of the inner punch 47 and the knockout 52. For this reason, it is promoted that the surplus portion of the preliminary tooth profile portion 8 in the first space portion 57 flows into the second space portion 58 of the axial center portion, and the surplus portion is lowered by the weight of the inflowed meat. The shape of 3 is bowl-shaped. Since the flow of meat is promoted in the first space portion 57, the precision forged portion 2 (tooth profile) having no missing wall is formed on the outer periphery of the intermediate forged product W3. Since the bowl-shaped surplus part 3 does not have a through-hole inside the bowl, excessive flow of meat from the precision forged part 2 to the surplus part 3 side is suppressed. Between the precision forged portion 2 on the outer periphery of the intermediate forged product W3 and the surplus portion 3 of the shaft center portion, a through-hole forming guide recess is formed so that the punching length is shortened when the surplus portion 3 is punched in a subsequent process. 10 is formed by the inner punch 47. When the intermediate forged product W3 is formed, the movable die 42 is retracted upward. Thereafter, the knockout 52 is moved upward by the knockout pin 53 and the intermediate forged product W3 is taken out from the die 55.

  Next, a piercing process for punching the surplus portion 3 of the intermediate forged product W3 by the piercing device 61 to form the through hole 4 will be described with reference to FIG. The intermediate forged product W <b> 3 is placed on the second support base 75 so as to be accommodated in the shaping space 77 of the first support base 74 by a transport device (not shown). Subsequently, the movable die 62 is lowered, and the movable die 62 is further lowered while the piercing stripper 66 presses the outer periphery of the intermediate forged product W3. The piercing stripper 66 stops descending due to the elasticity of the spring 65, but the piercing punch 67 formed in the piercing stripper 66 further descends and punches the surplus portion 3 of the intermediate forged product W3 to form the through hole 4. Thus, the forged product W4 is formed. Then, when the through hole 4 is formed, the piercing punch 67 rises with the piercing stripper 66 pressing the outer periphery of the intermediate forging product W3, and the fitting between the piercing punch 67 and the through hole 4 of the forging product W4 is released. Is done. Thereafter, the piercing stripper 66 is also retracted upward, and the forged product W4 is carried out.

  Therefore, according to the method for forming a forged product of the present invention, the forged product W4 having the through hole 4 in the axial center portion and the precision forged portion 2 on the outer periphery is formed from the substantially disk-shaped preliminary forged product W2. In the method, the movable die 42 forging the pre-forged product W2 and the fixed die 51 are brought into contact with each other to form a die-sculpting space 59 whose outer periphery is closed, and the movable die 42 and the fixed die 51 are formed on the outer periphery of the pre-forged product W2. The intermediate forged product W3 in which the surplus portion 3 is formed in a non-contact state with at least a part of the movable die 42 and the fixed die 51 at the axial center portion of the pre-forged product W2 Since the precision forged part forming process to obtain and the pierce forming process of punching the surplus part 3 of the intermediate forged product W3 to form the through hole 4, the meat of the precision forged part 2 formed on the outer periphery is the axis. Flows into the surplus part 3 formed in the part, and the precision forging part 2 The flow of accelerated, is not caused underfill the tooth profile is precision forged part 2 of the outer periphery of the intermediate forging W3. Further, the surplus portion 3 to be molded is in a non-contact state with at least a part of the movable die 42 and the fixed die 51, and the pressing area of the movable die 42 is reduced, so the molding load of the second forging device 41 is reduced. be able to.

  Further, in the molding device 21 of the intermediate forging product W3 in which the precision forging part 2 is molded on the outer periphery of the substantially disk-shaped pre-forging product W2, the mold of the molding device 21 is in contact with the movable die 42 and the fixed die 51. An engraved space 59 whose outer periphery is closed is formed, and the engraved space 59 whose outer periphery is closed includes a first space portion 57 having the same shape as the precision forged portion 2, and at least a part of an axial center portion of the intermediate forged product W3. Since the second space portion 58 is brought into a non-contact state, the forging method can be realized. Moreover, since it has the 2nd space part 58 which is in a non-contact state with at least one part of the axial center part of the intermediate forging product W3, the pressing area of the 2nd forging apparatus 41 becomes small, and the molding load of the 2nd forging apparatus 41 is reduced. Can be lowered.

  In the embodiment of the present invention, the tooth shape is formed on the precision forged portion 2 on the outer periphery of the intermediate forged product W3. However, the outer periphery may have a substantially circular shape or a different shape such as a boss. Moreover, although the surplus part 3 of the intermediate forged product W3 is in a non-contact state with the upper and lower surfaces of the movable die 42 and the fixed die 51, either one surface may be in a contact state. The number of dies, punches, pins, knockouts, and support dies constituting the movable dies 22, 42, 62 and the fixed dies 31, 51, 71 may be divided into different numbers or integrated. The second forging device 41 forms a closed die-cut space 59 by the contact between the inner peripheral portion 55 a of the die-cutting space 59 of the die 55 and the outer peripheral portion 46 a of the outer punch 46. A closed die-sculpting space may be formed by bringing the outer periphery of the engraving space 59 into contact with the inner periphery of the outer punch 46.

It is a cross-sectional top view showing the shaping | molding method of the forge product which has the precision forge part and through-hole of this invention. It is a fragmentary sectional top view showing the formation process which shape | molds the preliminary forging goods of this invention. It is a partial section top view showing the forming process which forms the intermediate forging product of the present invention. It is a fragmentary sectional top view showing the formation process which shape | molds the forge product which has the precision forge part and through-hole of this invention.

Explanation of symbols

2 Precision forging part 3 Extra part 4 Through hole
7 First positioning convex portion 42 Moving die 51 Fixed die 41 Molding device 57 First space portion 58 Second space portion 59 Die-sculpting space with closed outer periphery
W1 Material W2 Pre-forged product W3 Intermediate forged product W4 Forged product

Claims (2)

In a molding method of molding a forged product (W4) having a through hole (4) in the axial center portion and a precision forged portion (2) on the outer periphery from a substantially disk-shaped preliminary forged product (W2),
Pressing the substantially disk-shaped material (W1) and forming the preliminary forged product (W2) having the first positioning convex part (7) in the axial center part;
The movable die (42) forging the preliminary forged product (W2) and the fixed die (51) come into contact with each other to form a die-sculpting space (59) whose outer periphery is closed, and the outer periphery of the preliminary forged product (W2). And forming the precision forged portion (2) by the movable die (42) and the fixed die (51),
The first positioning convex part (7) is deformed in the axial center part of the preliminary forged product (W2), and the bowl-like shape is brought into a non-contact state with both the movable mold (42) and the fixed mold (51). A precision forged part forming step for obtaining an intermediate forged product (W3) in which the surplus part (3) is formed;
A piercing process for punching the surplus part (3) of the intermediate forged product (W3) to form a through hole (4);
A method for forming a forged product. The method for forming a forged product according to claim 1, wherein the precision forged portion (2) has a tooth profile .

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