JP2011241905A - Stud bolt and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stud bolt capable of appropriately fastening a member to be fastened with the erected stud bolt to the other member to be fastened, and a method of manufacturing the stud bolt.SOLUTION: This stud bolt 1 includes a head part 10 including a seat surface 12 opposed to one surface of the member to be fastened, and a shaft part 30 integrated into the head part 10, inserted into a through hole passing through the member to be fastened and erected on the other surface side of the member to be fastened. The shaft part 30 includes a bolt part 32, an annular flange part 34 formed on an outer periphery of the shaft part 30 between the head part 10 and the bolt part 32, a first annular groove 36 formed on the outer periphery of the shaft part 30 between the head part 10 and the annular flange part 34, and a second annular groove 38 formed on the outer periphery of the shaft part 30 between the annular flange part 34 and the bolt part 32. A first groove bottom diameter φ1 of the first annular groove 36 is smaller than an outer diameter φ2 of the annular flange part 34. A second groove bottom diameter φ3 of the second annular groove 38 is smaller than an outer diameter φ4 of the bolt part 32 and the outer diameter φ2 of the annular flange part 34.

Description

  The present invention relates to a stud bolt and a method for manufacturing a stud bolt.

  Conventionally, stud bolts have been used. The stud bolt is inserted into a through-hole formed in one fastened member and used to fasten one fastened member and another fastened member in a state of being erected on one fastened member. It is done. And the technique regarding a stud bolt is proposed conventionally (for example, refer patent document 1, patent document 2, patent document 3).

  In Patent Document 1, in a stud bolt that is attached by embedding a head portion in a metal substrate by press working, a flange portion is integrally projected on a shaft portion between the head portion and the screw portion, and the flange portion and the head portion. A groove portion is formed between the groove portion and a concave portion is provided on the inner surface of the head located outside the groove portion, so that the portion of the metal substrate that undergoes plastic deformation during pressing is filled into the groove portion and the concave portion. Things have been proposed.

  In Patent Document 2, a non-circular protrusion having a convex portion extending in the outer peripheral direction is provided on the head seat surface, and a thin plate-like fastening target is provided near a joint portion between the non-circular protrusion and a shaft portion in which a screw thread is screwed. In a screw provided with an annular groove in which an object is located, and further provided with a guide portion that is connected to the annular groove and expands the prepared hole of the object to be fastened, the screw is located between the noncircular protrusion and the annular groove. An annular ring protruding slightly on the guide side is provided, and when the convex part of the non-circular protrusion presses the object to be fastened, a part of the surplus of the fastened object is guided into the annular groove near the concave part of the non-circular protrusion. What has been proposed is proposed.

  In Patent Document 3, in a press-type stud bolt in which a flange-shaped head is press-fitted and embedded from one side of a hole in a plate material and the shaft portion is implanted on the other side of the plate material, In addition, an annular protrusion having an outer diameter equal to the outer diameter of the threaded portion of the outer screw of the shaft portion is formed integrally with the shaft portion, and an annular groove is formed between the annular protrusion and the head. ing.

Japanese Utility Model Publication No. 49-4522 Japanese Patent Laid-Open No. 10-54414 JP 2006-38026 A

  By the way, there are various thicknesses of the fastened members fastened (fixed) by the stud bolts. For example, it may be necessary to fasten a member to be fastened with a small thickness. And even if it is a case where a stud bolt is used for the fastening of the to-be-fastened member of any thickness, the fastening needs to be performed suitably. Here, the following points are important in order to suitably fasten the fastened member with the stud bolt. That is, the stud bolt needs to be suitably fixed to the one member to be fastened and erected. Further, the distance between the seat surface of the head of the stud bolt and the seat surface of the nut when the nut is fitted in the stud bolt is preferably equal to or less than the thickness of the entire fastening member in the stacked state. It must be less than that.

  An object of this invention is to provide the manufacturing method of the stud bolt and stud bolt which can fasten the to-be-fastened member by which the stud bolt was erected, and another to-be-fastened member suitably.

  One aspect of the present invention made in view of the above-described conventional problems is inserted into a through-hole penetrating one surface and the other surface of the fastened member from the one surface toward the other surface, A stud bolt fixed to the fastened member in a state of being erected on the side of the other surface, including a head including a seating surface facing the one surface, and the head; and A shaft portion that is inserted into the through-hole and is erected on the other surface side, and the shaft portion is formed on the outer periphery of the shaft portion between the bolt portion and the head portion and the bolt portion. An annular flange portion, a first annular groove formed on an outer periphery of the shaft portion between the head portion and the annular flange portion, and the shaft portion between the annular flange portion and the bolt portion. A second annular groove formed on the outer periphery, and the first groove bottom diameter of the first annular groove is smaller than the outer diameter of the annular flange portion. , The second groove bottom diameter of the second annular groove is a stud bolt, wherein the bolt part has a smaller diameter than the outer diameter of the outer diameter and the annular flange portion of.

  According to this, the incomplete thread part in a bolt part can be made into a small stud bolt. That is, the second annular groove can function as a relief portion when threading to form the bolt portion. Therefore, it becomes possible to arrange the complete screw part of the bolt part close to the head side, and the nut can be fitted to the head closer to the position.

  The stud bolt can be configured as follows. That is, the head portion is formed on the seat surface adjacent to the first annular groove so as to protrude from the seat surface to the shaft portion side, and the head portion from the outer periphery of the base portion. And an uneven portion formed on the seat surface so as to extend to the outer peripheral side of the portion, and the outer diameter of the pedestal portion may be larger than the outer diameter of the annular flange portion. .

  According to this, when fixing the stud bolt to the member to be fastened, the base portion protrudes from the seat surface facing one surface of the member to be fastened to the shaft portion side and is adjacent to the first annular groove. It is possible to plastically deform the portion of the fastened member that faces the first annular groove. The first annular groove is filled with the portion of the fastened member that has been plastically deformed, and the stud bolt can be suitably fixed to the fastened member in the insertion direction of the shaft portion and in the opposite direction. Further, when the stud bolt is fixed to the member to be fastened, the projection of the uneven portion formed on the seating surface facing one surface of the member to be fastened so as to extend from the outer periphery of the base portion to the outer periphery of the head. It is possible to cause the portion to be squeezed into one surface of the fastened member facing the concave and convex portion, and to plastically deform the portion of the fastened member toward the concave portion of the concave and convex portion. And a recessed part is filled with the part of the to-be-fastened member plastically deformed, and a stud bolt can be suitably fixed to a to-be-fastened member in the state which cannot be rotated. That is, according to this stud bolt, an anti-extrusion load against the falling-off of the stud bolt fixed to the member to be fastened is secured by plastic deformation of the member to be fastened by the pedestal, and a torque load against the rotation of the stud bolt is also obtained. It can be ensured by the uneven portion.

  Moreover, the convex part which forms the said uneven | corrugated | grooved part may be formed in the shape of a taper toward the protrusion direction of the said convex part. According to this, it is possible to reduce a load for causing the convex portion to be difficult to be inserted into one surface of the member to be fastened. And the contact area of a convex part and a to-be-fastened member can be enlarged in the state which put the convex part into the one surface of the to-be-fastened member difficult.

  Further, the pedestal portion that forms the pedestal portion and is adjacent to the first annular groove may be a flat surface. According to this, the contact between the pedestal portion and one surface of the fastened member becomes surface contact, and the portion of the fastened member facing the pedestal portion can be smoothly plastically deformed toward the first annular groove. .

  In another aspect of the present invention, a head including a seating surface facing one surface of the member to be fastened, and the head are integrated with the one surface and the other surface of the member to be fastened. A shaft portion that is inserted into the through-hole penetrating and is erected on the side of the other surface, and the shaft portion is disposed on an outer periphery of the shaft portion between the bolt portion and the head portion and the bolt portion. The formed annular flange, the first annular groove formed on the outer periphery of the shaft portion between the head and the annular flange portion, and the shaft portion between the annular flange portion and the bolt portion. A first groove bottom diameter of the first annular groove is smaller than an outer diameter of the annular flange, and a second groove bottom diameter of the second annular groove is A stud bolt manufacturing method having a smaller diameter than the outer diameter of the bolt portion and the outer diameter of the annular flange portion, and forming the head by forging a rod-shaped material. A head forging step and a shaft forging step for forcing the material to form the shaft portion. In the shaft forging step, the portion of the material for forming the second annular groove Forming the second annular groove with a concave portion of the material and forming the second annular groove in the outer diameter direction of the material to form the annular flange portion. The manufacturing method is characterized in that the first annular groove is formed by forming the annular flange portion.

  According to this, the stud bolt which has the outstanding function mentioned above can be manufactured suitably. In addition, this other side surface of this invention can also be specified as a manufacturing method of the above-mentioned stud bolt which added the structure to the stud bolt which concerns on one side surface of this invention.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the stud bolt and stud bolt which can be fastened suitably to the to-be-fastened member by which the stud bolt was erected, and another to-be-fastened member can be obtained.

It is a figure which shows a stud bolt. (A) is a front view, (b) is a bottom view, (c) is an enlarged view of part A shown in FIG. 1 (a), and (d) is a B--shown in FIG. 1 (b). It is B line sectional drawing. (A)-(c) is a figure which shows each state for adhering a stud bolt to a to-be-fastened member. (A)-(g) is a figure explaining the 1st process-the 3rd process of the manufacturing method of a stud bolt. (A) is a front view of the structure formed at a 1st process, (b) is the bottom view. (C) is a front view of the structure formed at a 2nd process, (d) is the bottom view. (E) is a front view of the structure formed at the 3rd process, (f) is the bottom view. (G) is the figure which expanded the small diameter part of the base part and the rod-shaped raw material among the structures shown in FIG.3 (e). (H)-(m) is a figure explaining the 4th process-5th process of the manufacturing method of a stud bolt. (H) is a front view of the structure formed at the 4th process, (i) is the bottom view. (J) is the figure which expanded the small diameter part of the base part, the annular collar part, the 1st annular groove, the 2nd annular groove, and the rod-shaped raw material among the structures shown in FIG.4 (h). (K) is a front view of the structure formed in the fifth step, and (l) is a bottom view thereof. (M) is the figure which expanded the base part, the annular collar part, the 1st annular groove, the 2nd annular groove, and the bolt part among the structures shown in FIG.4 (k). (A)-(c) is a figure explaining the manufacturing method of the stud bolt of a comparison object about the manufacturing method of a stud bolt.

  Embodiments for carrying out the present invention will be described with reference to the drawings. The present invention is not limited to the configurations described below, and various configurations can be employed in the same technical idea. For example, some of the configurations shown below may be omitted or replaced with other configurations. Moreover, you may make it include another structure.

(Stud)
The stud bolt 1 will be described with reference to FIGS. 1 (a) to 1 (d) and FIGS. 2 (a) to 2 (c). The stud bolt 1 is formed of the same material as various known bolts that have been used conventionally. For example, it is formed of a steel material such as chrome / molybdenum steel. The stud bolt 1 includes a head portion 10 and a shaft portion 30 as shown in FIGS. The shaft portion 30 and the head portion 10 are integrated. As shown in FIGS. 2A to 2C, the shaft portion 30 is inserted into a through hole 56 that penetrates one surface 52 and the other surface 54 of the fastened member 50. That is, the stud bolt 1 is inserted into the through hole 56 of the member to be fastened 50 from the one surface 52 toward the other surface 54 and is erected on the other surface 54 side. 50 is fixed.

  The head 10 includes a seating surface 12. The seat surface 12 that forms the head portion 10 faces one surface 52 of the fastened member 50. The head 10 includes a pedestal portion 14 and an uneven portion 18. The pedestal portion 14 is formed on the seat surface 12 adjacent to a first annular groove 36 of the shaft portion 30 described later so as to protrude from the seat surface 12 toward the shaft portion 30. The pedestal portion 14 includes a pedestal surface 16. The pedestal surface 16 that forms the pedestal portion 14 is a plane adjacent to the first annular groove 36. The concavo-convex portion 18 is formed on the seat surface 12 so as to extend from the outer periphery of the pedestal portion 14 to the outer peripheral side of the head 10. The concavo-convex portion 18 is formed by repeatedly forming a plurality of convex portions 20 and a plurality of concave portions 22 at equal intervals. As shown in FIG. 1C, each convex portion 20 is formed in a tapered shape toward the protruding direction of the convex portion 20. Specifically, the convex portion 20 is formed with an acute angle θ at its tip. Here, regarding the height in the axial direction of the pedestal part 14 and the convex part 20 with respect to the seating surface 12, as shown in FIG. 1A, the height H1 of the pedestal part 14 is the height of the convex part 20. It is set higher than the height H2.

  The shaft portion 30 includes a bolt portion 32, an annular flange portion 34, a first annular groove 36, and a second annular groove 38, and is formed by these portions. The bolt part 32 constitutes a male screw. In order to fasten the fastened member 50 on which the stud bolt 1 is erected to the bolt part 32 and other fastened members (not shown in FIGS. 2A to 2C), a nut (see FIG. 2 (a) to (c) are not shown) are fitted (screwed together). The annular flange portion 34 is formed on the outer periphery of the shaft portion 30 between the head portion 10 and the bolt portion 32. The first annular groove 36 is formed on the outer periphery of the shaft portion 30 between the head portion 10 and the annular flange portion 34. The second annular groove 38 is formed on the outer periphery of the shaft portion 30 between the annular flange portion 34 and the bolt portion 32.

  In the stud bolt 1, the first groove bottom diameter φ1 of the first annular groove 36 is smaller than the outer diameter φ2 of the annular flange 34 as shown in FIG. The second groove bottom diameter φ3 of the second annular groove 38 is smaller than the outer diameter φ4 of the bolt portion 32 and the outer diameter φ2 of the annular flange portion 34, as shown in FIG. The outer diameter φ5 of the pedestal portion 14 is larger than the outer diameter φ2 of the annular flange portion 34 as shown in FIG. Since the first groove bottom diameter φ1 of the first annular groove 36 is smaller than the outer diameter φ2 of the annular flange 34, the outer diameter φ5 of the pedestal portion 14 is the first groove bottom diameter of the first annular groove 36. Larger than φ1.

  Next, the fixation of the stud bolt 1 to the fastened member 50 will be described with reference to FIGS. 2B and 2C, illustration of a part of the concavo-convex portion 18 is omitted in order to clarify the relationship between the pedestal portion 14 and the fastened member 50, and the like. As shown in FIG. 2A, the worker who has started the action of fixing inserts the shaft portion 30 of the stud bolt 1 into the through hole 56. The shaft portion 30 is inserted from the one surface 52 side of the fastened member 50 toward the other surface 54 side.

  Here, the through hole 56 is slightly larger than the outer diameter φ <b> 2 of the annular flange 34, and is a through hole having a diameter that fits with the annular flange 34. Therefore, when the shaft portion 30 is further inserted on the other surface 54 side from the state of FIG. 2A, the annular flange portion 34 has a clearance fit between the annular flange portion 34 and the through hole 56. In the state, it is inserted into the through hole 56. That is, as shown in FIG. 2B, the stud bolt 1 is inserted into the through hole 56 while being centered with respect to the through hole 56. In addition, the dashed-dotted line shown in FIG.2 (b) shows the axial center of the stud bolt 1, and the centerline of the through-hole 56, Comprising: The both have corresponded and have shown notionally (FIG. 2). The same applies to (c)). And the stud bolt 1 will be in the state which the base part 14 contact | connected the one surface 52 of the to-be-fastened member 50, as shown in FIG.2 (b). Specifically, the pedestal surface 16 comes into surface contact with the opening edge of the through hole 56 on the one surface 52 side.

  In the state of FIG. 2B, the operator presses the head 10 against the other surface 54 side using a predetermined device such as a press machine, and further inserts the stud bolt 1 into the other surface 54 side. To do. That is, the operator presses the head 10 and inserts the pedestal portion 14 into one surface 52 of the fastened member 50. As a result, the opening edge of one surface 52 that is in surface contact with the pedestal surface 16 is plastically deformed toward the first annular groove 36 that coincides with the insertion direction of the stud bolt 1. That is, the opening edge of one surface 52 plastically deformed is plastically deformed toward the first annular groove 36 adjacent to the pedestal 14 as shown in FIG. Is done.

  Here, in the stud bolt 1, the volume of the opening edge portion of one surface 52 that is in surface contact with the pedestal surface 16 and is filled in the first annular groove 36 by insertion of the stud bolt 1 is equal to that of the first annular groove 36. It is set to be larger than the groove volume. In other words, in the stud bolt 1, the outer diameter φ5 of the pedestal portion 14 is an opening edge portion that is plastically deformed with respect to the diameter of the through hole 56 (substantially the same diameter slightly larger than the outer diameter φ2 of the annular flange portion 34). Is set to be larger than the groove volume of the first annular groove 36.

  When the stud bolt is fixed to the fastened member, the volume of the portion of the fastened member that is filled in the annular groove corresponding to the first annular groove 36, that is, the volume of the portion of the fastened member that is plastically deformed is If it is set smaller than the groove volume of the groove, the following state is obtained. That is, in such a case, the part to be fastened is not filled in the entire annular groove. And in the state which the stud bolt was fixed to the to-be-fastened member, the unfilled space | gap is formed in the inside of this annular groove. Therefore, the extrusion-proof load with respect to the falling-off of the stud bolt fixed to the member to be fastened is reduced. For this reason, a separate measure may be required.

  Moreover, the head 10 is pressed from the state shown in FIG. 2B, and the height H1 of the pedestal portion 14 and the height H2 of the convex portion 20 (the heights H1 and H2 are shown in FIGS. When the pedestal portion 14 is difficult to insert into the one surface 52 of the fastened member 50 by a difference ΔH with respect to FIG. 3G, the convex portion 20 formed in a tapered shape in the protruding direction. The tip is in contact with one surface 52. And when further pressed, the convex part 20 will be hard to squeeze one side 52, as shown in FIG.2 (c). As a result, the portion of the one surface 52 that is in contact with the convex portion 20 is plastically deformed toward the concave portion 22 and is filled in the concave portion 22.

  In this manner, the stud bolt 1 is centered with respect to the through hole 56 and fixed to the fastened member 50 as shown in FIG. In addition, after the stud bolt 1 is fixed to the fastened member 50, the stud bolt 1 standing on the other surface 54 side of the fastened member 50 is another fastened to be fastened to the fastened member 50. It is passed through a through hole formed in the member. Then, a nut is fitted into the bolt portion 32 in a state where the fastened member 50 and another fastened member are overlapped. Thereby, the fastened member 50 and the other fastened members are fastened by the stud bolt 1 and the nut.

  According to the stud bolt 1, the opening edge can be plastically deformed toward the first annular groove 36 in a state where the pedestal surface 16 is in surface contact with the opening edge of the one surface 52. Therefore, a force can be suitably applied to the opening edge, and the opening edge can be smoothly plastically deformed toward the first annular groove 36. Further, since the volume of the opening edge that undergoes plastic deformation and the volume of the first annular groove 36 are set as described above, the first annular groove 36 is entirely filled with the plastically deformed opening edge. can do.

  Further, in the stud bolt 1, the shape of the convex portion 20 that is inserted into the one surface 52 of the fastened member 50 is formed in a tapered shape toward the protruding direction. Therefore, it is possible to reduce the load related to the pressing for biting compared to the case where the shape is not such. In addition, the contact area with the fastened member 50 can be increased in a state where the convex portion 20 is difficult to insert on one surface 52. Further, in the stud bolt 1, the uneven portion 18 is formed so as to extend from the outer periphery of the pedestal portion 14 to the outer peripheral side of the head 10. Therefore, in the state where the stud bolt 1 is fixed to the fastened member 50, the torque required for the rotation of the stud bolt 1 increases, and the stud bolt 1 can be made difficult to rotate.

  Therefore, according to the stud bolt 1, an anti-extrusion load against the falling-off of the stud bolt 1 fixed to the fastened member 50 is ensured by plastic deformation of the fastened member 50 by the pedestal portion 14. A torque resistant load can be secured by the concavo-convex portion 18. And the stud bolt 1 can be suitably fixed to the fastened member 50.

  In addition, the fixation of the stud bolt 1 to the fastened member 50 may be in a state in which the entire head 10 is not easily fastened to the fastened member 50, unlike FIG. In this case, in order to further improve the torque resistance load for preventing the rotation of the stud bolt 1, a configuration such as a knurling may be formed on the outer peripheral surface of the head 10.

(Stud bolt manufacturing method)
The stud bolt 1 is manufactured by a manufacturing method including a first process to a fifth process. In the first step, for example, a rod-shaped material 60 as shown in FIGS. 3A and 3B is obtained by cutting a rod having a predetermined length and a circular cross-sectional shape into a predetermined dimension. Is formed. As shown in FIG. 3B, the rod-shaped material 60 has a circular cross-sectional shape.

  In the second step, as shown in FIGS. 3C and 3D, one end side of the rod-shaped material 60 is forged in the axial direction using the second step mold, and formed in the first step. A large diameter portion 62 is formed on one end side of the rod-shaped material 60. The large diameter portion 62 becomes the head 10. Further, the portion of the rod-shaped material 60 excluding the large diameter portion 62, that is, the small diameter portion 64 having a small diameter with respect to the large diameter portion 62 becomes the shaft portion 30.

  In the third step, the large-diameter portion 62 formed in the second step is further formed using a third-step mold corresponding to the shape of the head 10 including the seat surface 12, the pedestal portion 14, and the uneven portion 18. Forging in the axial direction. That is, in the third step, the large-diameter portion 62 was forged in the axial direction, and the pedestal portion 14 and the concavo-convex portion 18 were formed including the seat surface 12 as shown in FIGS. A head 10 is formed. As shown in FIG. 3A, the pedestal portion 14 is formed such that the height in the axial direction is H1 with the seat surface 12 as a reference. In addition, in FIG.3 (e), illustration of the uneven | corrugated | grooved part 18 is abbreviate | omitted (the same also about FIG.4 (j), (m) mentioned later).

  In the fourth process, a pair of fourth process molds, specifically a fixed die and a moving die, having a protruding portion and a relief portion are used. The protrusion has a shape corresponding to the second annular groove 38. The escape portion is formed by a space formed in the outer diameter direction of the small diameter portion 64 (same as the outer diameter direction of the rod-shaped material 60). The protruding portion and the escape portion are continuously formed in an adjacent state. In the fourth step, the portion 64a (see FIGS. 3E and 3G) of the small diameter portion 64 in which the second annular groove 38 is formed is annularly formed in the axial direction by the protruding portion of the fourth process die. It is plastically deformed in the direction in which the flange 34 is formed, that is, on the head 10 side. Then, as shown in FIGS. 4 (h) and 4 (i), and more specifically in FIG. 4 (j), the second annular groove 38 is formed by making the portion 64a of the small diameter portion 64 concave.

  Specifically, a pair of fourth process molds are arranged so that the protruding part and the escape part of the fixed die face each other, and the protruding part and the escape part of the moving die face each other. The portion 64a of the small diameter portion 64 is sandwiched between the two. And in the sandwiched state, refer to the direction of the arrow perpendicular to the axial direction of the small-diameter portion 64 (same as the axial direction of the rod-shaped material 60) (for example, the direction of the arrow described as “movement direction” in FIG. 4I) ) Relatively move the set of fourth process molds. Specifically, the moving die is moved in this moving direction. Thereby, the small diameter portion 64 (the rod-shaped material 60) is in a direction corresponding to the moving direction of the set of fourth process molds (for example, refer to the direction of the arrow described as “Rotation direction” in FIG. 4I). Rotate to. A concave groove portion is formed in the portion 64a of the small diameter portion 64 while the depth is gradually increased, and a second annular groove 38 having a predetermined depth is formed.

  When the second annular groove 38 is formed, the portion 64a of the small diameter portion 64 plastically deformed by the protruding portion of the fourth process mold is plastically deformed toward the head 10 side. Specifically, the portion 64a of the small-diameter portion 64 plastically deformed by the protrusion of the fourth process mold is plastically deformed toward the continuous relief portion in a state adjacent to the protrusion. A portion 64a of the small-diameter portion 64 plastically deformed toward the escape portion (the head 10 side) is raised in the outer diameter direction of the small-diameter portion 64 (the rod-shaped material 60) in the space forming the relief portion. A portion 34 is formed. Further, the annular flange 34 is formed by the protrusion of the portion 64 a of the small diameter portion 64, so that between the annular flange 34 and the pedestal portion 14, specifically between the annular flange 34 and the pedestal surface 16. Thus, a first annular groove 36 is formed adjacent to the pedestal surface 16. The fourth process mold has a structure that does not restrain the plastically deformed portion 64a of the small diameter portion 64 from the side of the head 10 when the portion 64a of the small diameter portion 64 undergoes plastic deformation. That is, the portion 64a of the small diameter portion 64 is plastically deformed in the space forming the escape portion according to only the force received from the protruding portion.

  In the fifth step, a pair of thread cutting molds, specifically a fixed die and a movement, having a molding surface having a shape corresponding to the shape of the crest and trough forming the male thread of the bolt portion 32. A die is used. In the fifth step, the pair of fifth step molds is pressed against the portion 64b (see FIG. 4 (h)) of the small diameter portion 64 where the bolt portion 32 is formed in the stud bolt 1. Then, as shown in FIGS. 4 (k) and 4 (l), more specifically, FIG. 4 (m), a bolt portion 32 is formed.

  Specifically, a pair of fifth process molds are arranged so that the molding surface of the fixed die and the molding surface of the moving die face each other, and the portion 64b of the small diameter portion 64 is sandwiched between the opposing molding surfaces. . Then, in the sandwiched state, a set of first in the direction perpendicular to the axial direction of the small diameter portion 64 (rod-shaped material 60) (see the direction of the arrow described as “movement direction” in FIG. 4L). Move the 5-step mold relatively. Specifically, the moving die is moved in this moving direction. As a result, the small diameter portion 64 (the rod-shaped material 60) is in a direction corresponding to the moving direction of the set of fifth process molds (for example, refer to the direction of the arrow described as “Rotation direction” in FIG. 4L). Rotate to. Then, a peak portion having a predetermined height and a valley portion having a predetermined depth are formed in the portion 64b of the small diameter portion 64 while gradually increasing the height of the peak portion and the depth of the valley portion, and the bolt portion 32 is formed. Is formed.

  In addition, in the manufacturing method of the stud bolt 1 mentioned above, a 2nd process and a 3rd process can be specified as a head forging process for forming the head 10. FIG. Further, the fourth step and the fifth step can be specified as a shaft portion forging step for forming the shaft portion 30. Here, the second step and the third step may be the same step. That is, the head 10 may be formed directly from the rod-shaped material 60 formed in the first step without forming the large diameter portion 62. Unlike this, the second step and the third step may be further subdivided steps. That is, the head 10 may be formed by forging one end side of the rod-shaped material 60 in the axial direction in a plurality of steps of three or more steps. The fourth step and the fifth step may be the same step. In this case, a mold having a form in which a fourth process mold and a fifth process mold are combined is used.

  The advantageous effect obtained by the stud bolt 1 manufactured by the manufacturing method including the first to fifth steps (hereinafter also referred to as “the manufacturing method of the present embodiment”) will be described. Hereinafter, a method different from the manufacturing method of the present embodiment (hereinafter, also referred to as “comparison method”) is to be compared, and a part of the structure formed in each step of the comparison method is illustrated in FIG. ) To (c). FIG. 5 (a) corresponds to FIG. 3 (g). FIG. 5B is a diagram corresponding to FIG. FIG.5 (c) is a figure corresponding to FIG.4 (m). In the description of the comparison method based on FIGS. 5A to 5C, the same reference numerals as the reference numerals attached to the stud bolts 1 are used for the same or similar configurations as the above-described stud bolts 1.

  First, the comparison method will be described. In the comparison method, the same process as the first process of the manufacturing method of the present embodiment is performed, and the rod-shaped material 60 (see FIGS. 3A and 3B) formed thereby is the target of the present embodiment. The same process as the 2nd process of a manufacturing method is performed. Then, for the configuration shown in FIGS. 3C and 3D formed in the second step, an intermediate portion 66 is formed in the small diameter portion 64 as shown in FIG.

  Next, as shown in FIG. 5B, the annular flange portion 34 and the first annular groove 36 are formed in the intermediate portion 66. In the comparison method, a pair of comparison method molds having a protrusion corresponding to the first annular groove 36 and a relief portion, specifically, a fixed die and a moving die are used. The escape portion is formed by a space formed in the outer diameter direction of the intermediate portion 66 (the same as the outer diameter direction of the rod-shaped material 60). The protrusion and the escape portion are continuously formed in an adjacent state.

  In the comparison method, a pair of comparison method molds are arranged so that the protruding portion and the relief portion of the fixed die face each other and the protruding portion and the relief portion of the moving die face each other. The portion 66a of the intermediate portion 66 is sandwiched. Then, as in the fourth step of the manufacturing method of the present embodiment, in the sandwiched state, the direction perpendicular to the axial direction of the intermediate portion 66 (same as the axial direction of the rod-shaped material 60) (FIG. 4 ( The pair of comparative molds are relatively moved in the “movement direction” shown in i)). As a result, the intermediate portion 66 (rod-shaped material 60) rotates in a direction corresponding to the moving direction of the pair of comparison method molds. A concave groove portion is formed in the portion 66a of the intermediate portion 66 while the depth is gradually increased, and a first annular groove 36 having a predetermined depth is formed.

  When the first annular groove 36 is formed, the portion 66a of the intermediate portion 66 plastically deformed by the protruding portion of the comparison method mold is plastically deformed to the side of the continuous relief portion in a state adjacent to the protruding portion. A portion 66a of the intermediate portion 66 plastically deformed toward the escape portion is raised in the outer diameter direction of the intermediate portion 66 (the rod-shaped material 60) in the space forming the escape portion, and the annular flange portion 34 is formed. In the comparison method, an annular groove corresponding to the second annular groove 38 of the stud bolt 1 is not formed. Thereafter, in the comparison method, as shown in FIG. 5 (c), with the boundary between the intermediate portion 66 and the small diameter portion 64 as a limit, the small diameter portion 64 is subjected to the same method as the fifth step of the manufacturing method of the present embodiment. Bolt portion 32 is formed.

  When comparing the manufacturing method of this embodiment and the comparison method, in the manufacturing method of this embodiment, the second annular groove 38 is formed to plastically deform the portion 64a of the small diameter portion 64 toward the head 10 side. At this time, the plastic deformation of the portion 64a of the small diameter portion 64 using the fourth process mold is not constrained from the head 10 side. Therefore, the stud bolt 1 formed with the annular flange 34 close to the head 10 side can be obtained. That is, according to the manufacturing method of the present embodiment, the dimension of the first annular groove 36 in the axial center direction is controlled by controlling the amount of plastic deformation of the portion 64a of the small diameter portion 64 by the protruding portion of the fourth process mold. Can be changed.

  On the other hand, in the comparison method, the thickness (axial thickness) of the projecting portion for forming the first annular groove 36 in the comparative mold is changed, so that the axial direction of the first annular groove 36 is changed. The dimensions can be changed. However, when the thickness of the protruding portion (thickness in the axial direction) is reduced in order to bring the annular flange portion 34 close to the head 10 side, the protruding portion is caused by the reaction force from the portion 66a of the intermediate portion 66. The part will be damaged. That is, in the comparison method, there is a limit to the setting of the dimension of the first annular groove 36 in the axial direction, and this cannot be suitably controlled as in the manufacturing method of the present embodiment.

  A second annular groove 38 is formed in the stud bolt 1. Therefore, in the formation of the bolt part 32 in the fifth step, the second annular groove 38 functions as a relief part at the time of threading. That is, according to the manufacturing method of the present embodiment, the bolt portion 32 can be suitably formed on the entire portion 64 b of the small diameter portion 64. Therefore, it is possible to reduce the incomplete thread portion in the bolt portion 32, and the stud bolt 1 having a structure in which the complete thread portion in the bolt portion 32 is disposed close to the head 10 side can be obtained. On the other hand, in the comparison method, since the second annular groove 38 is not formed, the incomplete thread portion formed in the shaft portion 30 becomes large.

  By the way, when the stud bolt is erected on one fastened member and one fastened member and another fastened member are fastened, the seat surface of the head and the seat surface of the nut fitted in the bolt portion When the distance between the two is greater than the thickness of the entire member to be fastened in the overlapped state, suitable fastening cannot be performed. Among the members to be fastened by the stud bolt, there is a thin member (thin plate). Even when a thin member to be fastened is fastened using a stud bolt, the distance between the seat surface of the head and the seat surface of the nut is a distance corresponding to the thickness of the whole fastened member in the stacked state. It is necessary to become.

  In the stud bolt 1 manufactured by the manufacturing method of the present embodiment, it is possible to reduce the dimension in the axial direction of the first annular groove 36 and bring the annular flange 34 close to the head 10. Moreover, the dimension of the incomplete thread part of the bolt part 32 can be made small, and a complete thread part can be arrange | positioned in proximity to the head 10. On the other hand, in the stud bolt manufactured by the comparison method, the dimension in the axial center direction of the first annular groove 36 cannot be made smaller than a predetermined constant value. Moreover, the dimension of the incomplete thread part becomes large.

  Therefore, in the stud bolt 1, the distance between the seat surface 12 of the head 10 and the seat surface of the nut fitted in the bolt portion 32 can be made smaller than in the case of the stud bolt according to the comparison method. In other words, the stud bolt 1 can cope with fastening of a to-be-fastened member having a smaller thickness, and the application range can be widened with respect to the thickness of the to-be-fastened member.

(Modification)
The configuration of the present embodiment can also be specified as follows. That is, in a state of being inserted into the through hole penetrating one surface and the other surface of the fastened member from the one surface toward the other surface, and standing on the other surface side, A stud bolt fixed to the member to be fastened, the head including a seating surface facing the one surface, and the head integrated with the head, inserted into the through hole, and on the side of the other surface And a head portion that is formed on the seat surface so that the head portion projects from the seat surface toward the shaft portion, and an outer periphery of the base portion. And an uneven portion formed on the seat surface so as to extend to the outer peripheral side of the shaft, and the shaft portion is formed on the outer periphery of the shaft portion between the bolt portion and the head portion and the bolt portion. Formed on the outer periphery of the shaft portion adjacent to the pedestal portion between the annular flange portion and the head portion and the annular flange portion. A stud bolt characterized in that the outer diameter of the pedestal portion is larger than the first groove bottom diameter of the first annular groove and the outer diameter of the annular flange portion. It can also be specified.

  According to this, the part of the to-be-fastened member which opposes a base part can be plastically deformed to the 1st annular groove side. Then, the first annular groove adjacent to the pedestal portion is filled with the portion of the fastened member that has been plastically deformed, and the stud bolt is suitably fixed to the fastened member in the insertion direction of the shaft portion and the opposite direction. Can do. Further, when the stud bolt is fixed to the member to be fastened, the projection of the uneven portion formed on the seating surface facing one surface of the member to be fastened so as to extend from the outer periphery of the base portion to the outer periphery of the head. It is possible to cause the portion to be squeezed into one surface of the fastened member facing the concave and convex portion, and to plastically deform the portion of the fastened member toward the concave portion of the concave and convex portion. And a recessed part is filled with the part of the to-be-fastened member plastically deformed, and a stud bolt can be suitably fixed to a to-be-fastened member in the state which cannot be rotated. That is, according to this stud bolt, an anti-extrusion load against the falling-off of the stud bolt fixed to the member to be fastened is secured by plastic deformation of the member to be fastened by the pedestal, and a torque load against the rotation of the stud bolt is also obtained. It can be ensured by the uneven portion.

  In the above description, the stud bolt 1 in which the height H1 of the base portion 14 is set higher than the height H2 of the convex portion 20 has been described as an example. In addition to such a configuration, a stud bolt in which the height H1 of the base portion 14 and the height H2 of the convex portion 20 are the same may be used. Moreover, it is good also as a stud bolt which set height H1 of the base part 14 low compared with the height H2 of the convex part 20. FIG.

  Furthermore, in the above, the case where the diameter of the through hole 56 is substantially the same diameter slightly larger than the outer diameter φ2 of the annular flange 34 is taken as an example, and the annular flange 34 and the through hole 56 are like a clearance fit. In the state, the configuration in which the annular flange 34 is inserted into the through hole 56 has been described as an example. In addition to such a configuration, the diameter of the through-hole 56 and the outer diameter φ2 of the annular flange 34 are the same, and the annular flange 34 and the through-hole 56 are in an intermediate fit state. 34 may be inserted into the through hole 56. In addition, the diameter of the through hole 56 is set to be substantially the same diameter slightly smaller than the outer diameter φ2 of the annular flange 34, and the annular flange 34 and the through hole 56 are in a state of interference fit. It is good also as a structure inserted in the through-hole 56. FIG. If the state is an intermediate fit or an interference fit, the stud bolt 1 is centered with respect to the through hole 56 as shown in FIG. 2B, as in the case of the clearance fit described above. It can be inserted into the through hole 56 in a state where it is in a fixed state and can be fixed to the fastened member 50 while being centered with respect to the through hole 56.

DESCRIPTION OF SYMBOLS 1 Stud bolt 10 Head 12 Seat surface 30 Shaft part 32 Bolt part 34 Annular collar 36 First annular groove 38 Second annular groove 50 Fastened member 52 One surface 54 The other surface 56 Through-hole φ1 The first annular groove 1st groove bottom diameter φ2 Outer diameter of annular flange φ3 Second groove bottom diameter of second annular groove φ4 Outer diameter of bolt part

Claims (5)

Inserted into a through-hole penetrating one surface and the other surface of the member to be fastened from the one surface toward the other surface, and standing on the other surface, A stud bolt fixed to a fastening member,
A head including a seating surface facing the one surface;
A shaft portion that is integral with the head portion, inserted into the through-hole, and erected on the other surface side;
The shaft portion is
Bolt part,
An annular flange formed on the outer periphery of the shaft portion between the head portion and the bolt portion;
A first annular groove formed on the outer periphery of the shaft portion between the head and the annular flange;
A second annular groove formed on an outer periphery of the shaft portion between the annular flange and the bolt portion;
The first groove bottom diameter of the first annular groove is smaller than the outer diameter of the annular flange,
The stud bolt characterized in that the second groove bottom diameter of the second annular groove is smaller than the outer diameter of the bolt part and the outer diameter of the annular flange part. The head is
A pedestal portion formed on the seat surface adjacent to the first annular groove so as to protrude from the seat surface toward the shaft portion;
Including an uneven portion formed on the seat surface so as to extend from the outer periphery of the pedestal portion to the outer peripheral side of the head,
The stud bolt according to claim 1, wherein an outer diameter of the pedestal portion is larger than an outer diameter of the annular flange portion.   The stud bolt according to claim 2, wherein the convex portion forming the concave and convex portion is formed in a tapered shape toward a protruding direction of the convex portion.   The stud bolt according to claim 2 or 3, wherein the pedestal portion that forms the pedestal portion and is adjacent to the first annular groove is a flat surface. A head including a seating surface facing one surface of the member to be fastened; and the head integrated with the head; inserted into a through-hole penetrating the one surface and the other surface of the member to be fastened; A shaft portion erected on the surface side of the shaft, wherein the shaft portion is a bolt portion, an annular flange formed on an outer periphery of the shaft portion between the head portion and the bolt portion, and the head portion A first annular groove formed on the outer periphery of the shaft portion between the ring portion and the annular flange portion, and a second annular groove formed on the outer periphery of the shaft portion between the annular flange portion and the bolt portion A first groove bottom diameter of the first annular groove is smaller than an outer diameter of the annular flange portion, and a second groove bottom diameter of the second annular groove is an outer diameter of the bolt portion and the annular shape. A method for producing a stud bolt having a smaller diameter than the outer diameter of the flange,
A head forging step of forging a rod-shaped material to form the head;
A shaft forging step for forming the shaft by forging the material,
In the shaft forging step, the portion of the material on which the second annular groove is formed is plastically deformed toward the head, the portion of the material is made concave, and the second annular groove is formed. The deformed portion of the material is raised in the outer diameter direction of the material to form the annular flange, and the first annular groove is formed by forming the annular flange. Method.

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