JP4066364B2 - Forging die - Google Patents

Description

  The present invention relates to a forging die for forging a long workpiece extending in the axial direction.

  As a long workpiece extending in the axial direction, for example, there is a tie rod arm used in a vehicle steering device. As shown in FIG. 4D, the arm W104 has a housing portion 165 formed at one end portion, and a female screw portion that is screwed into the mating member is formed inside the other end portion 167, and the housing portion 165 at one end portion is formed. And the other end 167 are connected by a shaft 162. Such an arm W104 is formed by forging a head 161 at one end of a round bar W100 as shown in FIG. 4 (A) and at one end as shown in FIG. 4 (A) to form an intermediate molded product W102. Next, as shown in FIG. 4 (c), the shaft 162 is bent into a desired shape to form the second intermediate molded product W103. Then, as shown in FIG. 165 was formed to produce the arm W104.

  Here, in recent years, automobile parts are required to be reduced in weight, and it is necessary to reduce the weight of the arm W104 as described above. In view of this, as shown in FIG. 1 (o), an arm W4 having a thin shaft portion for lightening can be considered. The other end portion 64 of the arm W4 is formed with a thick portion 63 having a diameter larger than that of the shaft portion 62 so as to form a female screw portion that is screwed with the mating member. When the arm W4 having a thin shaft portion is formed, a head 61 for forming the housing portion 65 is formed at one end of the round bar W0 as shown in FIG. After forming the preform W1 as shown in a), the shaft diameter is reduced. At this time, in a forging device that presses in a general axial direction, the thick part 63 is formed so that the diameter of the thick part 63 formed at the other end of the intermediate molded product W2 is larger than the diameter of the shaft part 62. 63 cannot be pulled out of the forging device. For this reason, it is conceivable to reduce the shaft diameter by performing a cutting process. However, if the cutting process is performed, there is a problem in that the number of processing steps increases and the cost increases.

Therefore, in the step of molding the intermediate article W2 from preform W1 by forging, in order to withdraw the thick portion 63 from the forging apparatus, can freely expand reduced radially has a divided portion divided in the circumferential direction divided It is conceivable to use a forging device having a die. At this time, a split die that is long in the axial direction is required in accordance with the length of the shaft portion 62 of the intermediate molded product W2, but the split die has a substantially conical shape having an outer peripheral taper. A problem arises in that the thickness of the tip of the diameter is reduced and the strength of the split die is lowered. Therefore, if the thickness of the tip of the split die is increased in order to increase the strength of the split die, there arises a problem that the mold becomes large.

  The problem to be solved is that when a long workpiece extending in the axial direction is forged, the split die having an outer peripheral taper that is a forging die also needs to be elongated in the axial direction in accordance with the workpiece. The thickness is reduced and the strength is lowered.

  A pair of first and second molds arranged in opposition to each other, the first mold is disposed so as to be movable back and forth with respect to the second mold, and for forging a long workpiece extending in the axial direction. In the mold, the second mold has an outer peripheral taper that is reduced in diameter from a large diameter portion at one end located on the first mold side toward a small diameter portion at the other end, and is divided in the circumferential direction. A split die that can be expanded and contracted in the direction perpendicular to the axis, and a ring that is disposed on the outer peripheral side of the split die and has an inner peripheral taper substantially the same as the outer peripheral taper of the split die on the inner periphery. The split die is continuous in the axial direction. Are arranged in a plurality, and are capable of moving forward and backward relative to the ring in the axial direction, and the large-diameter portions of the other divided dies that are in contact with the small-diameter portions of the continuously arranged divided dies are larger than the small-diameter portions that are in contact with each other. The most important feature is the diameter.

  In the forging die according to the present invention, since a plurality of divided dies are arranged in the axial direction, the length of one divided die in the axial direction can be shortened when a long workpiece extending in the axial direction is formed, and thus the tip becomes thin. Since it has a sufficient thickness without increasing the size of the apparatus, the strength of the split die can be increased, and a long workpiece extending in the axial direction can be formed by forging.

  The purpose of forming a long workpiece extending in the axial direction with a forging die was realized by increasing the strength without increasing the size of the forging die.

  FIG. 1 shows a step of forging a tie rod arm W4 used in an automobile steering device or the like as an example of a long workpiece extending in the axial direction. First, as shown in FIG. 1A, a cylindrical material W0 is forged, and a head 61 is formed at one end as shown in FIG. 1A to form a preform W1. Subsequently, the preform W1 is forged, a thick portion 63 is formed at the other end 64 as shown in (c), and the shaft portion 62 connecting the head 61 and the other end 64 is a thick portion. An intermediate molded product W2 having a smaller diameter than 63 is formed. Subsequently, the shaft portion 62 of the intermediate molded product W2 is bent and molded into a desired shape to form the second intermediate molded product W3 as shown in FIG. 65 is formed to complete an arm W4 as shown in FIG.

  A forging device 1 including a forging die for forming an intermediate molded product W2 from the preform W1 in the manufacturing process of the arm W4 will be described with reference to FIG.

FIG. 2 shows a forging device 1 including a first mold 11 and a second mold 21. Reference numeral 21 denotes a fixed second mold, which includes divided dies 22 and 26 having a carving space 38 into which the preform W1 is placed, and a substantially cylindrical mandrel 35 disposed on the inner peripheral side of the divided dies 22 and 26. The ring 40 is disposed on the outer peripheral side of the divided dies 22 and 26. The split dies 22 and 26 are composed of four split parts that are split in the circumferential direction, and the split parts can be expanded and contracted in the radial direction of the preform W1. The split dies 22 and 26 have a substantially conical shape having outer peripheral tapers 22c and 26c that gradually decrease in diameter from the large diameter portions 22a and 26a arranged on the first mold 11 side toward the small diameter portions 22b and 26b, and are axially arranged. Two divided dies 22 and 26 are arranged side by side. The first split die 22 is disposed on the first mold 11 side, and a large-diameter side end is formed with a recess 23 that is substantially the same shape as the axial half of the head 61 of the preform W1, and is continuous from the recess 23. A straight portion 24 is formed. In the second divided die 26, the large diameter portion 26 a of the second divided die 26 abuts on the small diameter portion 22 b of the first divided die 22, and is continuous with the straight portion 24 of the first divided die 22 and has a larger diameter than the straight portion 24. The large straight portion 27 is formed. The ring 40 arranged on the outer peripheral side of the divided dies 22 and 26 has two rings 28 and 30 arranged side by side in the axial direction, and the first ring 28 and the first ring 28 arranged on the first mold 11 side. The second ring 30 arranged on the side opposite to the first mold is connected by a metal detent pin 31. The first ring 28 and the second ring 30 hold the first split die 22 and the second split die 26, respectively. The inner peripheral surface of the first ring 28 is formed with an inner peripheral taper 28 c substantially the same as the outer peripheral surface of the first divided die 22, and the inner peripheral surface of the second ring 30 is also substantially the same as the outer peripheral surface of the second divided die 26. The same inner peripheral taper 30c is formed. A step portion 25 is formed on the outer peripheral side of the end portion on the large diameter 22 a side of the first split die 22, and an annular flange 32 is disposed in contact with the step portion 25 and the first ring 28. Are connected by a first ring 28 and a screw 33. The first ring 28 has a circumferential recess 29 formed on the outer peripheral surface. A case 41 is disposed on the outer peripheral side of each ring 28, 30, and a pin 42 is fitted between the case 41 and the first ring 28. Further, a small spring 36 is disposed around the mandrel 35, and a plurality of large springs 37 having a larger diameter than the small spring 36 are disposed on the outer side of the small spring 36 and below the second ring 30 with a circumferential interval. Has been.

Next, the movable first mold 11 will be described. 12 is a cylindrical punch, and a recess 13 having substantially the same shape as the upper half of the head 61 for pressing the head 61 of the preform W1 is formed at the end on the second mold 21 side. Yes. A cylindrical punch holder 14 for holding the punch 12 is disposed on the outer peripheral side of the punch 12.

  Next, a process of forming the intermediate molded product W2 using the forging device 1 will be described.

  First, as shown in the left half part of FIG. 2, the preform W1 is introduced so that the head 61 is disposed on the first mold 11 side in the engraving space 38 of the second mold 21. At this time, the split dies 22 and 26 are in an expanded state, and a slight gap is generated between the inner peripheral surfaces of the split dies 22 and 26 and the preform W1. After the preform W1 is placed at a predetermined position, the punch 12 of the first mold 11 is moved to the second mold 21 as shown in the right half of FIG. 2, and the punch 12 is the head of the preform W1. It abuts on the part 61 and the 1st division | segmentation die | dye 22, and presses both. Then, since the first split die 22 moves downward, the inner diameter of the first split die 22 is reduced along the inner peripheral taper 28c of the first ring 28, and the space between the preform W1 and the first split die 22 is reduced. The gap disappears. The same applies to the second divided die 26. The second divided die 26 moves downward in conjunction with the first divided die 22, and the inner diameter of the second divided die 26 is reduced along the inner peripheral taper 30c of the second ring 30. The split die 22 and the second split die 26 are in contact with the split portions. Further, the punch 12 presses the preform W1 and the first split die 22, and the other end 64 of the preform W1 comes into contact with the mandrel 35. Further, the first split die 22 and the second split die 26, which have been further reduced in diameter, move further downward together with the first ring 28 and the second ring 30, and as shown in FIG. Expands into a carved space 38 defined by the large straight portion 27 of the second split die 26 and the upper end surface of the mandrel 35, and a thick portion 63 is formed at the other end portion 64, and the shaft portion 62 is formed as a finished product W4. By forming the same diameter, the intermediate formed product W2 is completed. Thereafter, the punch 12 is retreated upward, and the first split die 22, the second split die 26 and the ring 40 are also moved upward by the biasing force of the small spring 36 and the large spring 37, and at the same time, the first split die 22 and the second split die 22 The split die 26 is expanded in diameter, and the intermediate molded product W2 is taken out from the forging device 1.

  In the above embodiment, the two divided dies 22 and 26 are continuously arranged in the axial direction. However, the number of divided dies is not limited and may be changed according to the length of the product.

It is a top view showing the manufacturing process of the long workpiece | work extended to an axial direction. The forging metal mold | die by the Example of this invention is represented, The left half part is a partial cross-sectional top view showing the state before shaping | molding and the right half part in the middle of shaping | molding. It is a partial cross-sectional top view showing the metal mold | die for forging by the Example of this invention, and showing the state after shaping | molding. It is a top view showing the manufacturing process of the conventional long workpiece.

Explanation of symbols

11 First mold
21 Second mold 22 (first) split die 22a (first split die) large diameter portion 22b (first split die) small diameter portion 22c (first split die) outer peripheral taper 26 (second) split die 26a (first) Two-part die) Large-diameter portion 26b (Second-part die) Small-diameter part 26c (Second-part die) Outer taper 28c (First ring) Inner taper 30c (Second ring) Inner taper 40 Ring W2 Workpiece

Claims (1)

A pair of first mold (11) and second mold (21) arranged opposite to each other is provided, and the first mold (11) is disposed so as to be able to advance and retreat with respect to the second mold (21) . In the forging die for forging a long workpiece (W2) extending in the axial direction, the second die (21) is a large-diameter portion at one end located on the first die (11) side. (22a, 26a) having an outer peripheral taper (22c, 26c) that decreases in diameter toward a small diameter portion (22b, 26b) at the other end, and a split die that is split in the circumferential direction and expandable / contractable in the direction perpendicular to the axis ( 22, 26) and the outer peripheral taper (28 c, 26 c) of the split die (22, 26), which is disposed on the outer peripheral side of the split die (22, 26). 30c) with a ring (40), the split dies (22, 26) in the axial direction Other than that, a plurality of the dies are continuously arranged, and can be moved forward and backward relative to the ring (40) in the axial direction, and in contact with the small-diameter portion (22b) of each of the divided dies (22) arranged continuously. A forging die characterized in that the large-diameter portion (26a) of the split die (26) has a larger diameter than the small-diameter portion (22b) that abuts.

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