JP2006136909A - Method for manufacturing bar shape member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a bar shape member having an opened hole on its one end and a flange provided on the other end, which method can provide almost uniform hardness the bar shape member without carrying out the quenching work. <P>SOLUTION: In the method for manufacturing the bar shape member 1 (Fig. (d)) having the opened hole 2 on its one end and the flange 3 provided on the other end, a raw material 11 (Fig. (a)) having a diameter which is larger than that of the stem portion 1a of the bar shape member 1 and is capable of forming the flange 3 by one cold forging process is subjected to an annealing treatment. After that, the raw material 11 is subjected to a cold forging process to obtain an intermediate material 15 (Fig. (b)) which has a large diameter portion 12 nearly equal to that of the diameter of the raw material 11 and a small diameter portion 13 nearly equal to that of the stem portion 1a. And then, the flange 3 is formed on the large diameter portion 12 side of the intermediate material 15 by a cold forging process (Fig. (c)), and then, the hole 2 is formed on the small diameter portion 13 side by a cold forging process (Fig. (d)). <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a metal rod-shaped member having a hole opened on one end side and a flange provided on the other end side.

  In recent years, automakers have been working on measures against exhaust gas and improving fuel economy while global environmental issues have been screamed. As measures for improving fuel efficiency, integration of parts and weight reduction of parts are being carried out. As such a component, there is a rod-shaped member 1 as shown in detail in FIG.

  The rod-shaped member 1 shown in FIG. 1 is made of metal, and its shaft portion 1a is formed in a round bar shape. The rod-shaped member 1 includes a first hole 2 opened on one end side in the axial direction, a flange 3 provided on the other end side in the axial direction, and a second hole 4 opened on the other end side in the axial direction. Have. The volume of the first hole 2 is larger than the volume of the second hole 4.

  The manufacturing method assumed when manufacturing this rod-shaped member 1 is demonstrated with reference to FIG. The rod-shaped member 1 is manufactured using cold forging by a pressing device to which a mold (not shown) is attached. The material 101 ((a) in FIG. 10) of the rod-shaped member 1 is formed in a round bar shape, and the diameter thereof substantially matches the diameter of the shaft portion 1a of the rod-shaped member 1 that is a finished product. Here, the reason why the diameter of the material 101 is made to substantially coincide with the diameter of the shaft portion 1a of the rod-shaped member 1 is to make the molding load necessary when molding the first hole 2 described below as small as possible. .

  In the manufacturing method of the rod-shaped member 1, first, the material 101 is annealed and subjected to a surface film treatment.

  Here, annealing and surface lubrication treatment will be described. When a metal is plastically processed, it undergoes work hardening due to internal strain, and due to a decrease in deformability (formability), subsequent plastic processing such as material cracking may become extremely difficult. Therefore, after some plastic working, heat treatment is performed for the purpose of removing internal strain and returning to the state before work hardening. This is annealing.

  Further, when plastic working is performed, a lubricant such as oil is used to reduce the frictional force at the contact portion between the workpiece such as the material 101 and the mold and to prevent seizure. In the cold forging process, since the contact surface pressure and the processing heat are very high, a solid lubricating film may be formed on the object to be processed to increase the lubricating effect. This treatment is a surface lubricating coating treatment, and is also called bonderite, bonderube or the like.

  Next, the first hole 2 is formed on one end side of the material 101 by forward extrusion using a mold to obtain the intermediate material 102 ((b) in FIG. 10). Here, the reason why the first hole 2 is formed before the flange 3 is that the first hole 2 is formed from the state without the flange 3 rather than the first hole 2 is formed from the state in which the flange 3 is formed. This is because the molding can be simplified and the control of the press apparatus can be simplified.

  Next, after subjecting the intermediate material 102 to surface lubrication treatment, the shaft diameter on the other end side of the intermediate material 102 is increased by upsetting using a mold, and the second end is set on the other end side. The preliminary shape 103 of the hole 4 is formed ((c) in FIG. 10).

  Next, after subjecting the intermediate material 102 to surface lubrication treatment, a preliminary shape 104 of the flange 3 is formed on the other end side of the intermediate material 102 ((d) in FIG. 10). The reason why the preliminary shape 104 of the flange 3 is formed is that the ratio of “length / diameter” of the intermediate material 102 is large, and therefore, if the flange 3 is formed on the intermediate material 102 by one processing, the intermediate material 102 This is because it is assumed that a buckling phenomenon or a lack of deformability occurs in 102 and molding becomes impossible.

  Next, before finishing forming the preliminary shape 104 to complete the flange 3, the intermediate material 102 is subjected to annealing and surface lubrication coating treatment. The reason for annealing is that the work of the preliminary shape 104 of the flange 3 causes work hardening in the intermediate material 102 and the workability of the intermediate material 102 increases.

  Next, finish molding of the second hole 4 and the flange 3 is performed on the other end side of the intermediate member 102 by upsetting using a mold, and the second hole 4 and the flange 3 are completed (FIG. 10). (E)). Thereby, the rod-shaped member 1 is completed.

  Thus, in the assumed manufacturing method, after forming the preliminary shape 104 of the flange 3 on the intermediate material 102, the final (second) annealing is performed to soften the intermediate material 102 as a whole, and then the intermediate material 102 Finishing the second hole 4 and the flange 3 on the other end side of 102, the rod-shaped member 1 is obtained. Therefore, in the rod-shaped member 1, the portion (flange 3 and its surroundings) formed after the last annealing is hardened by work hardening, but the shaft portion 1a having the other first holes 2 is the second hole. 4 and the flange 3 are hardly affected by the finish molding, and thus remain soft. Therefore, the hardness of the rod-shaped member 1 varies greatly depending on the part. If the hardness variation is large, stress concentration may be caused. For this reason, in order to make the hardness of the rod-shaped member 1 uniform, it is necessary to perform quenching. Thereby, the problem that a manufacturing process increases will arise.

  An object of the present invention is to make it possible to make the hardness of the rod-shaped member uniform even without quenching when manufacturing the rod-shaped member having a hole opened on one end side and a flange provided on the other end side. Is to do.

  The invention described in claim 1 is a method for manufacturing a rod-shaped member having a first hole opened on one end side and a flange formed on the other end side, wherein the diameter is larger than the diameter of the shaft portion of the rod-shaped member. And subjecting the material having a diameter capable of forming the flange by a single cold forging process to an annealing process, and subjecting the annealed material to an extrusion process by a cold forging process to obtain a diameter of the material. Forming an intermediate material having a large diameter portion having substantially the same diameter and a small diameter portion smaller than the large diameter portion and having a diameter substantially equal to the diameter of the shaft portion, and the large diameter portion of the intermediate material Forming the flange by cold forging on the side and forming the first hole by cold forging on the small-diameter portion side of the intermediate material.

  According to a second aspect of the present invention, in the method for manufacturing a rod-shaped member having a first hole opened on one end side and a flange formed on the other end side, the diameter is larger than the diameter of the shaft portion of the rod-shaped member. The flange having a diameter that can be formed by a single cold forging process is subjected to extrusion molding by cold forging process, and a larger diameter part having a diameter substantially the same as the diameter of the material and the larger diameter part. A step of forming an intermediate material having a small diameter and a small diameter portion substantially the same as the diameter of the shaft portion; a step of subjecting the intermediate material to an annealing treatment; and the large portion of the intermediate material subjected to the annealing treatment. Forming the flange by cold forging on the diameter side, and forming the first hole by cold forging on the small diameter side of the intermediate material that has been annealed. It is characterized by that.

  According to a third aspect of the present invention, in the method for manufacturing a bar-shaped member according to the first or second aspect, the bar-shaped member has a second hole having a smaller volume than the first hole opened on the other end side. The second hole is formed by a step of forming the intermediate member and a step of forming the flange.

  According to a fourth aspect of the present invention, in the method for manufacturing a rod-shaped member according to the first aspect, in the step of performing the annealing treatment, a surface lubricating film treatment is performed on the material after the annealing treatment.

  According to a fifth aspect of the present invention, in the method for manufacturing a rod-shaped member according to the second aspect, in the step of performing the annealing treatment, a surface lubricating film treatment is performed on the intermediate material after the annealing treatment. .

  According to the present invention, the hardness of the rod-shaped member can be made to be uniform even without quenching when manufacturing the rod-shaped member having a hole opened on one end side and a flange provided on the other end side.

  A first embodiment of the present invention will be described with reference to FIGS.

  FIG. 1 is a longitudinal front view showing a rod-like member 1 manufactured by the manufacturing method of the present embodiment. The rod-shaped member 1 of the present embodiment is, for example, cut into the final shape shown in FIG. 1 to become a nut.

  As shown in FIG. 1, the rod-shaped member 1 is made of metal, and the shaft portion 1a is formed in a round bar shape. The rod-shaped member 1 includes a first hole 2 opened on one end side in the axial direction, a flange 3 provided on the other end side in the axial direction, and a second hole 4 opened on the other end side in the axial direction. Have. The volume of the first hole 2 is larger than the volume of the second hole 4. Further, the first hole 2 and the second hole 4 are positioned linearly along the axis of the rod-shaped member 1.

  A method for manufacturing the rod-shaped member 1 will be described with reference to FIGS. FIG. 2 is a process diagram for explaining a manufacturing process of the rod-shaped member 1, and FIGS. 3 to 8 are longitudinal front views showing a part of the manufacturing process of the rod-shaped member 1.

  As shown in FIG. 2A, the material 11 of the rod-shaped member 1 is formed in a columnar shape. The diameter of the material 11 is set to a diameter that is larger than the diameter of the shaft portion 1a of the rod-like member 1 and that allows the flange 3 to be formed by one cold forging process.

  In manufacturing the rod-shaped member 1 from the material 11, first, the material 11 is subjected to annealing and surface lubrication treatment. By this annealing treatment, the hardness of the intermediate material 15 is lowered overall.

  Thereafter, the following cold forging is performed. Cold forging is performed using a press device (not shown) to which various upper and lower molds 21 to 26 are attached. In the following description, “up and down” in a workpiece such as the material 11 to be processed by the pressing device refers to up and down in a state of being set on the molds 21 to 26 in the pressing device.

  First, the material 11 that has been subjected to annealing and surface lubrication treatment is subjected to cold forging to provide a large-diameter portion 12 that is substantially the same diameter as the material 11 and a diameter smaller than that of the large-diameter portion 12. A small diameter portion 13 having a diameter substantially the same as the diameter of the shaft portion 1a is formed, and a preliminary shape 14 of the second hole 4 is formed in an upper portion on the large diameter portion 12 side, so that an intermediate member 15 (FIG. 2B) is formed. ) See). Specifically, as shown in FIG. 3, after the material 11 is set in the lower mold 21, the upper mold 22 is lowered to perform forward extrusion. As a result, as shown in FIG. 4, the intermediate member 15 having the large-diameter portion 12 at the top, the preliminary shape 14 of the second hole 4, and the small-diameter portion at the bottom is formed.

  Next, the flange 3 is formed on the large diameter portion 12 by cold forging on the intermediate material 15, the second hole 4 is finished, and the preliminary shape 17 of the first hole 2 is formed on the small diameter portion 13. Mold. (See FIG. 2 (c)). Specifically, as shown in FIG. 6, as shown in FIG. 6, after the intermediate material 15 with the large-diameter portion 12 on the upper side is set in the lower mold 23, the upper mold 24 is lowered. The flange 3 is formed on the upper portion of the intermediate material 15, and the second hole 4 is formed by finishing the preliminary shape 14 of the second hole 4, and the lower portion (small diameter portion 13) of the intermediate material 15 is formed. ), The preliminary shape 17 of the first hole 2 is formed. Here, the preliminary shape 17 of the first hole 2 is intended to facilitate the main processing of the first hole 2 in the next step, and the work hardening of the intermediate material 15 by the processing of the preliminary shape 17 is as follows. It is low enough to perform the main processing of the first hole 2 in the next step without annealing.

  Next, the main processing of the first hole 2 is performed by cold forging on the lower portion (small diameter portion 13) of the intermediate material 15 in which the preliminary shape 17 of the first hole 2 is formed, and the first hole 2 is finished. Then, the rod-shaped member 1 is obtained (see FIG. 2D). Here, the rod-shaped member in FIG. 2D is shown upside down with respect to the intermediate member 15 in FIG. Details of the processing at this time will be described. As shown in FIG. 7, the intermediate member 15 is turned upside down with respect to the previous step (see FIG. 2C), that is, the second hole 4 and the flange 3 are positioned on the upper side. Set in the lower mold 25. In this state, as shown in FIG. 8, when the upper die 26 is lowered, the first hole 2 is formed by backward extrusion (hole pressing). More specifically, the upper mold has a structure including a movable sleeve 26a and a punch 26b, and the movable sleeve 26a and the punch 26b are lowered at the same time. First, the movable sleeve 26 a comes into contact with the flange 3 of the intermediate material 15. The movable sleeve 26a is fixed in position while being in contact with the flange 3 at a predetermined pressure, whereby the intermediate member 15 is fixed by the movable sleeve 26a and the lower mold 25. On the other hand, the punch 26b continues to descend even after the movable sleeve 26a stops and abuts against the intermediate member 15 to compress the intermediate member 15. Thereby, the intermediate material 15 fixed by the movable sleeve 26a and the lower mold 25 is deformed so as to flow upward between the movable sleeve 26a and the punch 26b, and the first hole 2 is formed. . Thereby, the rod-shaped member 1 is completed.

  As described above, in the present embodiment, in the process of forming the rod-shaped member 1 from the material 11, first, the material 11 is annealed to soften the hardness of the material 11 and to increase the hardness of the material 11. After homogenization, the material 11 is formed into a rough shape into an intermediate material 15 shown in FIG. 2A, and cold forging is applied to both ends of the intermediate material 15 to form the shape (first hole 2, flange 3). ) To form work hardening on the intermediate member 15 as a whole and complete the rod-shaped member 1, so that the hardness of the rod-shaped member 1 is nearly uniform. That is, in the manufacturing method of the rod-shaped member 1 according to the present embodiment, the hardness of the rod-shaped member 1 can be made close to uniform without quenching.

  Further, in the present embodiment, the finish molding of the second hole 4 formed on the same side as the flange is performed simultaneously with the flange molding, so that the second hole 4 is completed before the flange molding. Thus, the finishing accuracy of the second hole 4 can be improved.

  In the present embodiment, in the step of performing the annealing process on the material 11, the surface 11 is subjected to the surface lubricating film process after the annealing process, whereby the next processing can be easily performed. Moreover, in this Embodiment, since a cold forging process is started, since annealing and surface lubrication process are not performed, the cold forging process of FIG.2 (b)-FIG.2 (d) is continued. The manufacturing process of the rod-shaped member 1 can be simplified. In addition, when aiming at the improvement of workability in each process rather than simplification of the manufacturing process of the rod-shaped member 1, after the intermediate material 15 shown in FIG. May be applied. Further, after the intermediate material 15 shown in FIG. 2C is molded, the intermediate material 15 may be subjected to surface lubrication treatment.

  Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are denoted by the same reference numerals, and description thereof is also omitted.

  FIG. 9 is a process diagram for explaining a manufacturing process of the rod-shaped member in the manufacturing method of the present embodiment. In this embodiment, instead of subjecting the material 1 to annealing and surface lubrication treatment, as shown in FIG. 9, an intermediate material 15 in which a large diameter portion 12 and a small diameter portion 13 are formed (see FIG. 9B). Annealing and surface lubrication treatment are performed on the surface. That is, in the present embodiment, in the process of forming the rod-shaped member 1 from the material 11, the material 11 is first formed into a rough shape into the intermediate material 15 shown in FIG. 9A, and the intermediate material 15 is annealed. After processing, the hardness of the intermediate material 15 is made soft overall and the hardness of the intermediate material 15 is made uniform overall, and then cold forging is applied to both ends of the intermediate material 15 to form the shape (first hole 2 The flange 3) is formed to cause work hardening on the intermediate member 15 as a whole, and the rod-like member 1 is completed. Thereby, the hardness of the rod-shaped member 1 approaches uniformly uniformly as a whole. Therefore, in the manufacturing method of the rod-shaped member 1 of the present embodiment, the hardness of the rod-shaped member 1 can be made close to uniform without quenching.

It is a vertical front view which shows the rod-shaped member manufactured by the manufacturing method of the 1st Embodiment of this invention. It is process drawing for demonstrating the manufacturing process of a rod-shaped member. It is a vertical front view which shows a part of manufacturing process of a rod-shaped member. It is a vertical front view which shows a part of manufacturing process of a rod-shaped member. It is a vertical front view which shows a part of manufacturing process of a rod-shaped member. It is a vertical front view which shows a part of manufacturing process of a rod-shaped member. It is a vertical front view which shows a part of manufacturing process of a rod-shaped member. It is a vertical front view which shows a part of manufacturing process of a rod-shaped member. It is process drawing for demonstrating the manufacturing process of the rod-shaped member in the manufacturing method of the 2nd Embodiment of this invention. It is process drawing for demonstrating the conventional manufacturing process of a rod-shaped member.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bar-shaped member 1a Shaft part 2 1st hole 3 Flange 4 2nd hole 11 Material 12 Large diameter part 13 Small diameter part 15 Intermediate material

Claims (5)

In a method for manufacturing a rod-shaped member having a first hole opened on one end side and a flange formed on the other end side,
Annealing the material having a diameter larger than the diameter of the shaft portion of the rod-shaped member and capable of forming the flange by a single cold forging process;
The material that has been subjected to the annealing treatment is subjected to extrusion molding by cold forging, and has a large diameter portion that is substantially the same diameter as the diameter of the material and a diameter that is smaller than the large diameter portion and substantially the same as the diameter of the shaft portion. Forming an intermediate material having a small diameter portion, and
Forming the flange by cold forging on the large diameter portion side of the intermediate material;
Forming the first hole by cold forging on the small diameter side of the intermediate material;
The manufacturing method of the rod-shaped member characterized by including. In a method for manufacturing a rod-shaped member having a first hole opened on one end side and a flange formed on the other end side,
A material having a diameter larger than the diameter of the shaft portion of the rod-shaped member and capable of forming the flange by one cold forging process is subjected to extrusion molding by cold forging, and the diameter of the material A step of forming an intermediate material having a large diameter portion having substantially the same diameter and a small diameter portion having a smaller diameter than the large diameter portion and the diameter of the shaft portion;
A step of annealing the intermediate material;
Forming the flange by cold forging on the large-diameter portion side of the intermediate material that has been annealed;
Forming the first hole by cold forging on the small diameter portion side of the intermediate material subjected to the annealing treatment;
The manufacturing method of the rod-shaped member characterized by including. The rod-shaped member has a second hole having a smaller volume than the first hole opened to the other end side,
The method for manufacturing a rod-shaped member according to claim 1 or 2, wherein the second hole is formed by a step of forming the intermediate member and a step of forming the flange.   2. The method for manufacturing a rod-shaped member according to claim 1, wherein, in the step of performing the annealing treatment, a surface lubricating film treatment is performed on the material after the annealing treatment. 3. The method for manufacturing a rod-shaped member according to claim 2, wherein in the step of performing the annealing treatment, a surface lubricating film treatment is applied to the intermediate material after the annealing treatment.

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