JP7073180B2 - Cold heading method for caulking nuts and caulking nuts - Google Patents

Description

In the present invention, a caulking nut, which is caulked and fixed to a plate-shaped member (attached member) that cannot be machined with a screw hole (female screw), and a screw (for example, a round flat head screw) or a bolt is screwed into the caulking nut. And its cold heading method.

Conventionally, a caulking nut is caulked and fixed to a plate-shaped member (attached member such as a steel plate or an aluminum plate) that cannot be machined with a screw hole, and the caulking nut and a screw screwed into the caulking nut (round flat machine screw, etc.). Alternatively, a technique of tightening and fixing other structures (electronic component support panel, printed circuit board, etc.) to a plate-shaped member with bolts is known.

FIG. 5 shows such a caulking nut 101. As shown in FIG. 5, the caulking nut 101 has a substantially cylindrical shape in which a screw hole (female screw) 102 is formed, and a caulking fixing portion 104 is formed on one end side of the nut main body portion 103. The caulking fixing portion 104 has a pilot portion 107 engaged with the nut mounting hole 106 of the plate-shaped mounted member 105 and a press-fit fixing portion 108 press-fitted into the peripheral edge of the nut mounting hole 106 of the mounted member 105. Has (see FIG. 6 (a)). Of these, the pilot portion 107 has a substantially cylindrical shape with a reverse taper that engages with the nut mounting hole 106 of the mounted member 105 with a slight gap, and is an axial tip surface (left end surface of FIG. 5B) 110. The outer diameter dimension is the largest, and the outer diameter dimension gradually decreases toward the root side (the right side along the axis CL in FIG. 5B) (undercut). The press-fitting fixing portion 108 is located adjacent to the pilot portion 107, and its outer diameter dimension is larger than the outer diameter dimension of the pilot portion 107 and the dimension of the hole 106 of the mounted member 105, and the outer diameter dimension of the nut main body portion 103. A substantially triangular groove 111 is continuously formed along the entire circumference (see FIG. 5A). Further, the caulking nut 101 is formed so that the length of the caulking fixing portion 104 along the axis CL is slightly shorter than the plate thickness dimension of the attached member 105. The groove 111 is a serration groove extending in the direction along the axis CL.

In the caulking nut 101 having such a shape, as shown in FIG. 6A, the pilot portion 107 is inserted into the nut mounting hole 106 of the mounted member 105, and the end surface 112 of the press-fit fixing portion 108 is inserted into the mounted member 105. Pressurized between the backing metal (lower mold) 115 and the punch (upper mold) 116 pressed against the front surface 113 and pressed against the back surface 114 of the attached member 105. As a result, as shown in FIG. 6B, the caulking nut 101 is a part (base material) of the attached member 105 in which the caulking fixing portion 104 is press-fitted into the attached member 105 and pressed by the press-fitting fixing portion 108. Plasticly flows so as to fill the gap between the reverse tapered pilot portion 107 and the nut mounting hole 106, and a part of the mounted member 105 meshes tightly with the substantially triangular groove 111 of the press-fit fixing portion 108 (FIG. 5), the end surface 110 of the pilot portion 107 is caulked and fixed to the attached member 105 so as not to protrude from the back surface 114 of the attached member 105. In the caulking nut 101 that is caulked and fixed to the attached member 105 in this way, the reverse tapered pilot portion 107 exerts a function of preventing the attached member 105 from coming off, and the substantially triangular groove 111 of the press-fit fixing portion 108. Is designed to exert a detent function with respect to the attached member 105 (see FIG. 6 (b)). Then, another structure (for example, a printed circuit board or an electronic component support panel) is closely arranged on the attached member 105 to which the caulking nut 101 is caulked and fixed so that the structure can be crimped. It is fastened and fixed to the attached member 105 with a screw or a bolt screwed into a nut (see Patent Document 1 (particularly, see FIGS. 6 and 7)).

Utility Model Registration No. 3157701

In the conventional caulking nut 101 shown in FIG. 5, since the screw hole 102 is a through hole, it can be machined by cold heading.

However, in the conventional caulking nut 101, the press-fitting and fixing portion 108 is formed to have a larger outer diameter than the pilot portion 107, and the nut main body 103 is formed to have a larger outer diameter than the press-fitting and fixing portion 108. Since the outer diameter dimension is changed in a stepwise manner along the axis CL in three steps, if the screw hole 102 is not a through hole (in the case of a bottomed screw hole 102), cold heading is performed. Was difficult (it was difficult to accurately plastically flow the material in the die) and was formed by cutting. As a result, the conventional caulking nut having a bottomed screw hole has a large amount of material wasted as chips, the production man-hours are high, and the product cost is high.

Therefore, an object of the present invention is to provide a caulking nut having a shape that enables cold heading and a cold heading method for the caulking nut.

In the present invention, the caulked fixing portion 3 is formed on one end side in the axial direction of the nut main body portion 2, and the caulked fixing portion 3 is engaged with the nut mounting hole 10 formed in the mounted member 6. The present invention relates to a caulking nut 1 that is caulked and fixed to a member 6. In the caulking nut 1 of the present invention, the caulking fixing portion 3 has the same diameter as the outer diameter of the nut main body portion 2 and is a press-fit fixing portion 4 extending along the axial direction from one end side in the axial direction of the nut main body portion 2. It has a substantially cylindrical pilot portion 5 having a diameter smaller than that of the press-fitting and fixing portion 4 and extending along the axial direction from one end side in the axial direction of the press-fitting and fixing portion 4. Further, the press-fitting and fixing portion 4 is recessed inward in the radial direction from the outer peripheral surface 4a having the same diameter as the outer diameter of the nut main body portion 2, and a recess 7 extending in the axial direction is provided along the circumferential direction. A plurality of the mounted members 6 are formed and press-fitted into the mounted member 6 to accommodate a part of the mounted member 6 in the recess 7 and fix the mounted member 6 in a detented state. Will be done. Further, the pilot portion 5 is formed so that the outer diameter on the axial tip surface 13 side engages with the nut mounting hole 10 of the mounted member 6, and the outer peripheral surface 11 is the axial tip surface. It is formed in a reverse taper shape in which the outer diameter dimension is gradually reduced from the 13 side toward one end side in the axial direction of the press-fitting and fixing portion 4, and when the press-fitting and fixing portion 4 is press-fitted into the attached member 6, the outer peripheral surface thereof is formed. A part of the mounted member 6 is accommodated in the gap 12 between the 11 and the inner peripheral surface 10a of the nut mounting hole 10, and is fixed to the mounted member 6 in a state of being prevented from coming off. A bottomed screw pilot hole 14 is opened in the axial tip surface 13 of the pilot portion 5.

In addition, the present invention
A caulking fixing portion 3 is formed on one end side of the nut body portion 2 in the axial direction.
The caulking fixing portion 3 has the same diameter as the outer diameter of the nut main body portion 2 and extends from one end side in the axial direction of the nut main body portion 2 along the axial direction, and the press-fitting fixing portion 4 is larger than the press-fitting fixing portion 4. It has a substantially cylindrical pilot portion 5 having a small diameter and extending along the axial direction from one end side in the axial direction of the press-fitting and fixing portion 4.
The press-fitting fixing portion 4 has a plurality of recesses 7 recessed inward in the radial direction from the outer peripheral surface 4a having the same diameter as the outer diameter of the nut main body 2 and extending along the axial direction. Formed,
The pilot portion 5 is formed in a reverse taper shape in which the outer peripheral surface gradually decreases in outer diameter dimension from the axial tip surface 13 side toward the axial end end side of the press-fit fixing portion 4.
A bottomed screw pilot hole 14 opens in the axial tip surface 13 of the pilot portion 5.
The present invention relates to a cold heading method for the caulking nut 1.
The cold heading method for the caulking nut 1 of the present invention is:
In the first cold heading step of pressurizing the round bar-shaped processing material 23 in the first mold 24 to form the axial tip side portion 26 of the processing material 23 in which the pilot portion 5 is formed into a truncated cone shape. ,
The processing material 23 taken out from the first mold 24 is pressed in the second mold 27 to form the nut main body 2 and the press-fitting fixing portion 4 in the processing material 23, and the processing material is formed. The second cold heading step of forming the small diameter shaft portion 31 on the axial tip side of the 23, and
The processing material 23 taken out from the second mold 27 is pressed in the third mold 34 to form a pre-machined hole in the first step of screw pilot hole processing, and from the inside of the third mold 34. The taken-out machined material 23 is set in the fourth die 38, and the screw pilot hole drilling rod 37 is pushed into the pre-machined hole 36 to form the screw pilot hole 14. With a third cold heading process , which has steps,
The processing material 23 taken out from the fourth mold 38 is set in the fourth cold heading mold 41, and the pilot partial forming rod 43 is inserted into the open end side of the screw pilot hole 14. It is characterized by having a fourth cold heading step of forming the pilot portion 5 on the small diameter shaft portion 31.

Since the caulking nut according to the present invention has the same outer diameter dimension between the press-fitting fixing portion and the nut main body portion, and the outer diameter dimension is changed in two stages between the pilot portion, the press-fitting fixing portion, and the nut main body portion. Cold heading is possible even if it has a bottomed screw pilot hole. As a result, the caulking nut according to the present invention can reduce the amount of wasted material, improve the production efficiency, and reduce the product cost as compared with the conventional caulking nut to be machined. can.

Further, according to the cold heading method of the caulking nut according to the present invention, the amount of wasted material can be reduced, the production efficiency can be improved, and the product cost can be reduced as compared with the conventional caulking nut to be machined. It is possible to reduce the cost.

It is a figure which shows the caulking nut which concerns on embodiment of this invention, FIG. 1 (a) is a front view of the caulking nut, FIG. FIG. 1 (d) is a cross-sectional view taken along the line A1-A1 of the above, and FIG. 1 (d) is a rear view of the caulking nut. FIG. 2A is a diagram showing a state before the caulking nut according to the embodiment of the present invention is caulked and fixed to the attached member, and FIG. 2B is a diagram showing a state before the caulking nut according to the embodiment of the present invention is attached. It is a figure which shows the state after caulking and fixing to a member. It is a figure which shows the cold heading method of the caulking nut which concerns on embodiment of this invention. FIG. 4A is a diagram showing a modification 1 of the caulking nut according to the present invention, and FIG. 4B is a diagram showing a modification 2 of the caulking nut according to the present invention. FIG. 5A is a front view of the caulking nut according to the conventional example, and FIG. 5B is a side view showing a part of the caulking nut according to the conventional example by breaking. FIG. 6A is a diagram showing a state before the caulking nut according to the conventional example is caulked and fixed to the attached member, and FIG. 6B is a diagram after caulking and fixing the caulking nut according to the conventional example to the attached member. It is a figure which shows the state of.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(Caulking nut)
FIG. 1 is a diagram showing a caulking nut 1 according to the present invention. Note that FIG. 1A is a front view of the caulking nut 1. Further, FIG. 1B is a side view of the caulking nut 1. Further, FIG. 1 (c) is a cross-sectional view of the caulking nut 1 cut along the line A1-A1 of FIG. 1 (a). Further, FIG. 1 (d) is a rear view of the caulking nut 1.

As shown in FIG. 1, the caulking nut 1 according to the present invention has a columnar nut main body 2 as if a round bar was cut to a predetermined length, and one end side of the nut main body 2 in the axial direction (FIG. 1 (FIG. 1). b) has a caulking fixing portion 3 integrally formed on the left end side along the axis CL).

The caulking fixing portion 3 has the same diameter as the outer diameter of the nut main body portion 2 and is axially oriented from one end side in the axial direction of the nut main body portion 2 (leftward along the axis CL in FIGS. 1B and 1C). A press-fitting and fixing portion 4 extending along the axis and an axial direction (along the axis CL in FIGS. 1B and 1C) from one end side in the axial direction of the press-fitting and fixing portion 4 having a smaller diameter than the press-fitting and fixing portion 4. It has a substantially cylindrical pilot portion 5 extending in the left direction). The caulking fixing portion 3 is formed so that the axial length (length along the axis CL) L1 is equal to or shorter than the plate thickness t of the mounted member 6. ing.

The press-fitting fixing portion 4 is recessed in a triangular shape (the shape seen from the front side is a triangular shape) inward in the radial direction from the outer peripheral surface 4a having the same diameter as the outer diameter of the nut main body portion 2 and along the axial direction ( A plurality of recesses 7 extending (along the axis CL) are continuously formed along the circumferential direction, and a triangular protrusion 8 is formed between the adjacent recesses 7 and 7. As shown in FIG. 2B, the press-fitting fixing portion 4 is press-fitted into the mounted member 6 (metal panel of the housing or the like) to accommodate a part of the mounted member 6 in the recess 7. Then, it is fixed to the attached member 6 in a state of being prevented from rotating.

The outer diameter of the pilot portion 5 on the front side is circular, and the outer diameter on the axial tip side (left end side in FIGS. 1B and 1C) is in the nut mounting hole 10 of the mounted member 6. The outer peripheral surface 11 is formed in a size to be engaged (see FIG. 2), and the outer peripheral surface 11 is axially one end side of the press-fitting fixing portion 4 from the axial tip side (right direction in FIGS. 1B and 1C). It is formed in a reverse taper shape in which the outer diameter dimension gradually decreases toward the direction. As shown in FIG. 2B, the pilot portion 5 has a gap 12 between the outer peripheral surface 11 and the inner peripheral surface 10a of the nut mounting hole 10 when the press-fitting fixing portion 4 is press-fitted into the mounted member 6. A part of the attached member 6 (the plastically flowed portion of the attached member 6) is accommodated in the reverse tapered gap 12), and is fixed to the attached member 6 in a state of being prevented from coming off. The pilot portion 5 is formed so that the axial length L2 is shorter than the plate thickness t of the attached member 6.

Further, in the pilot portion 5, a screw pilot hole 14 is opened in the center of the axial tip surface (axial one-sided surface) 13 in FIGS. 1 (b) and 1 (c). The screw pilot hole 14 is a bottomed hole, and is a nut main body portion 2 along the axial direction (right direction in FIGS. 1B and 1C) from the axial tip surface 13 of the pilot portion 5. Extends to. Then, in this screw pilot hole 14, the female screw 15 is cut by a tap, so that a screw (not shown) of a shaft portion such as a round flat head screw or a screw (not shown) of a shaft portion of a bolt is screwed. The screw holes 16 to be combined are formed.

The caulking nut 1 having the above structure is formed by cutting a wire rod such as iron-based metal, stainless steel, or aluminum to a predetermined size to form a round bar-shaped caulking nut material, and then cold-pressing the caulking nut material. It is processed and formed into the shape shown in FIG. The caulking nut 1 according to the present embodiment shown in FIG. 1 exemplifies a crimping nut 1 in which a screw hole 16 is formed, but the present invention is not limited to this, and a crimp nut 1 in which only a screw pilot hole 14 is formed is shipped as a product. However, the tapping screw may be screwed while cutting the female screw with the tapping screw at the time of use.

FIG. 2 illustrates a state in which the caulking nut 1 according to the present invention is fixed to the attached member 6. Note that FIG. 2A shows a state in which the pilot portion 5 of the caulking nut 1 is engaged with the nut mounting hole 10 of the mounted member 6, and the state before the caulking nut 1 is caulked and fixed to the mounted member 6. It is a figure which shows. Further, FIG. 2B is a diagram showing a state after the caulking nut 1 is caulked and fixed to the attached member 6.

First, as shown in FIG. 2A, the pilot portion 5 of the caulking nut 1 is inserted into the nut mounting hole 10 of the mounted member 6 and caulked as a preparatory step for caulking and fixing the caulking nut 1 to the mounted member 6. The tip surface 4a of the press-fitting fixing portion 4 of the nut 1 is abutted against the surface (one side surface) 17 of the attached member 6. Then, a backing metal 20 having a diameter larger than the outer diameter of the caulking nut 1 is abutted against the back surface 18 side of the attached member 6 so as to come into surface contact with the back surface 18 of the attached member 6. Further, on the side of the other end surface 21 of the caulking nut 1 in the axial direction (the back surface (21) side of the nut main body 2), punches 22 for applying caulking force to the caulking nut 1 are arranged so as to face each other. Here, the punch 22 has a diameter larger than the outer diameter of the caulking nut 1 and the axial direction of the caulking nut 1 and the like so that the entire surface of the other end surface 21 of the caulking nut 1 in the axial direction can be pressed toward the attached member 6. It has a flat surface parallel to the end surface 21.

Next, as shown in FIG. 2B, a caulking force for pushing the caulking nut 1 toward the mounted member 6 is applied to the punch 22, and the axial tip surface 13 of the pilot portion 5 of the caulking nut 1 is a padding 20. The press-fitting fixing portion 4 of the caulking nut 1 is pushed into the attached member 6 by the caulking force of the punch 22 until it comes into contact with. Then, when the press-fitting and fixing portion 4 of the caulking nut 1 is pushed into the attached member 6, a part of the attached member 6 plastically flows and is accommodated in the recess 7 of the press-fitting and fixing portion 4, and the attached member is accommodated. A part of 6 is plastically flowed and is accommodated in the gap 12 (reverse tapered gap 12) between the outer peripheral surface 11 of the pilot portion 5 and the inner peripheral surface 10a of the nut mounting hole 10 without a gap. As a result, the caulking nut 1 is fixed to the attached member 6 in a state of being prevented from rotating and coming off.

The caulking nut 1 according to the present embodiment as described above has the same outer diameter dimension of the press-fitting fixing portion 4 and the nut main body portion 2, and the outer diameter of the pilot portion 5, the press-fitting fixing portion 4, and the nut main body portion 2 is the same. Since the dimensional change is made in two stages, the caulking nut material can be accurately plastically flowed inside the die, and cold heading is possible. As a result, the caulking nut 1 according to the present embodiment can reduce the amount of wasted material, improve the production efficiency, and reduce the product cost as compared with the conventional caulking nut 101 formed by cutting. I was able to plan.

Further, when the caulking nut 1 according to the present embodiment is used by being caulked and fixed to the attached member 6 of the housing for accommodating electronic parts, one end of the screw hole 16 is closed, so that the screw hole is a screw hole. It is possible to prevent metal powder, dust, etc. adhering to the screws or bolts screwed into the 16 from entering the inside of the housing through the screw holes 16.

(Cold heading method for caulking nuts)
FIG. 3 is a diagram showing a cold heading method for the caulking nut 1 according to the present embodiment. The caulking nut 1 according to this embodiment is formed through the following first to fourth cold heading steps. In the following description of the cold heading method for the caulking nut 1, the upper and lower parts of the processed material 23 are for convenience of explaining the posture of the processed material 23 in FIG. 3, and the first to fourth cold heading are used. It does not limit the posture of the processed material 23 in the process. Further, in FIGS. 3 (b) to 3 (f), the processed material 23 is shown in cross section on the right side from the center line in order to make it easier to understand the cold heading process.

(1) First cold heading process (FIG. 3 (b))
The round bar-shaped processed material 23 having a predetermined length shown in FIG. 3A is pressed by the pressurizing member 25 in the first mold 24, and the axial tip side portion 26 for forming the pilot portion 5 is formed. It is formed in a truncated cone shape, and the axial length and outer diameter of the processed material 23 are adjusted to the dimensions that enable the implementation of the second cold heading step, which is the next step. In the description of the cold heading method for the caulking nut 1 shown in FIG. 3, the lower surface side of the processed material 23 (the side forming the pilot portion 5) is the front end side, and the upper surface side of the processed material 23 is the rear end side.

(2) Second cold heading process (FIG. 3 (c))
Next, the processing material 23 taken out from the first mold 24 is pressurized by the pressurizing member 28 in the second mold 27, and the large-diameter shaft portion 30 and the axial tip side of the large-diameter shaft portion 30 thereof. The small-diameter shaft portion 31 located in is formed (formed into a two-stage shaft shape), and the press-fitting fixing portion 4 is formed on the tip side of the large-diameter shaft portion 30 at the center of the tip surface 31a of the small-diameter shaft portion 31. A conical recess 32 is formed. In this second cold heading process, the nut main body portion 2 and the press-fitting fixing portion 4 are formed on the large-diameter shaft portion 30 of the processing material 23. Further, in this second cold heading step, the small diameter shaft portion 31 of the processed material 23 is formed with a pilot portion 5 through the third and fourth cold heading steps described later. Further, in this second cold heading step, the conical tip 32 formed on the tip surface 31a of the small diameter shaft portion 31 is engaged with the conical tip of the screw pilot hole drilling rod 33 described later, and the screw is screwed. It functions as a positioning guide for the pilot hole drilling rod 33.

(3) Third cold heading process (FIGS. 3 (d) to 3 (e))
As shown below, this third cold heading step includes a first step of screw pilot hole drilling (FIG. 3 (d)) and a second step of screw pilot hole drilling (FIG. 3 (e)). are doing.

i. First step of thread pilot hole drilling (Fig. 3 (d))
The processed material 23 taken out from the second mold 27 is set in the third mold 34 with the small diameter shaft portion 31 facing down, and the rear end side of the large diameter shaft portion 30 is pressurized by the pressurizing member 35. The first thread pilot hole drilling rod 33 is pushed in from the tip surface 31a of the small diameter shaft portion 31, and the premachined hole 36 for forming the screw pilot hole 14 opens in the tip surface 31a of the small diameter shaft portion 31. It is formed. The pre-machined hole 36 is formed shallower than the hole depth of the screw pilot hole 14, and functions as a guide hole for the second screw pilot hole drilling rod 37 used in the second step of the screw pilot hole drilling later. do.

ii. Second step of thread pilot hole drilling (Fig. 3 (e))
Next, the processing material 23 taken out from the third mold 34 is set in the fourth mold 38 with the small diameter shaft portion 31 facing down, and the rear end side of the large diameter shaft portion 30 is applied by the pressurizing member 40. After being pressed, the second screw pilot hole drilling rod 37 is pushed into the premachined hole 36 from the tip surface 31a of the small diameter shaft portion 31, and the screw pilot hole 14 is formed.

(4) Fourth cold heading process (FIG. 3 (f))
Next, the processing material 23 taken out from the 4th die 38 is set in the 4th cold heading die (pilot partial forming die) 41 with the small diameter shaft portion 31 facing down, and the large diameter shaft is set. The rear end side of the portion 30 is pressurized by the pressurizing member 42, the pilot portion forming rod 43 is inserted into the open end side of the screw pilot hole 14, and the small diameter shaft portion 31 is formed by the tapered portion 44 of the pilot portion forming rod 43. It is expanded into an inverted taper shape.

As shown above, the caulking nut 1 according to the present embodiment shown in FIGS. 1 and 2 is formed through the first to fourth cold heading steps. Then, the screw pilot hole 14 of the caulking nut 1 becomes a screw hole 16 by cutting the female screw. In the cold heading method for the caulking nut 1 according to the present embodiment, when the depth of the screw pilot hole 14 is shallow, the second step of screw pilot hole machining in the third cold heading step is omitted, and preliminary machining is performed. The hole 36 may be a screw pilot hole 14.

According to the cold heading method for the caulking nut 1 according to the present embodiment as described above, the amount of wasted material can be reduced and the production efficiency can be improved as compared with the conventional caulking nut to be machined. , Product cost can be reduced.

(Deformation example of caulking nut 1)
FIG. 4A is a front view showing a modification 1 of the caulking nut 1 according to the present invention. In the caulking nut 1 according to the present modification 1 shown in FIG. 4A, the shape of the recess 7 of the press-fitting fixing portion 4 (the shape seen from the front side) is an arc shape, and the recesses 7 and 7 adjacent to each other have an arc shape. A substantially triangular protrusion 8 is formed between the two. The caulking nut 1 according to the present modification 1 is press-fitted and fixed in the same manner as the caulking nut 1 shown in FIG. 1, in which the shape (shape seen from the front side) of the recess 7 of the press-fit fixing portion 4 is triangular. When the portion 4 is press-fitted into the attached member 6, the press-fitting fixing portion 4 is fixed to the attached member 6 in a detented state.

(Modification example 2 of caulking nut)
FIG. 4B is a front view showing a modification 2 of the caulking nut 1 according to the present invention. The caulking nut 1 according to the present modification 2 shown in FIG. 4B is 6 along the circumferential direction of the press-fitting and fixing portion 4 so that the outer shape of the press-fitting and fixing portion 4 as viewed from the front side is a hexagonal shape. A recess 7 is formed. The caulking nut 1 according to the present modification 2 is press-fitted and fixed in the same manner as the caulking nut 1 shown in FIG. 1, in which the shape (shape seen from the front side) of the recess 7 of the press-fit fixing portion 4 is triangular. When the portion 4 is press-fitted into the attached member 6, the press-fitting fixing portion 4 is fixed to the attached member 6 in a detented state.

(Other variants)
In the present invention, the recess 7 of the press-fitting and fixing portion 4 of the caulking nut 1 is not limited to the shapes exemplified in the above-described embodiment and each modification, and the press-fitting and fixing portion 4 is fixed in a state of being prevented from rotating to the attached member 6. Any shape can be used.

1 ... Caulking nut, 2 ... Nut body, 3 ... Caulking fixing part, 4 ... Press-fit fixing part, 5 ... Pilot part, 6 ... Attached member, 7 ... Recess, 10 ... Nut Mounting hole, 10a ... Inner peripheral surface, 11 ... Outer peripheral surface, 12 ... Gap, 13 ... Axial tip surface, 14 ... Screw pilot hole, 23 ... Processing material, 24 ... 1st mold, 26 ... Axial tip side part, 27 ... 2nd mold, 31 ... Small diameter shaft part, 31a ... Tip surface, 34 ... 3rd mold, 43 ... Pilot part forming rod

Claims (3)

A caulking fixing portion is formed on one end side in the axial direction of the nut main body portion, and the caulking fixing portion is caulked and fixed to the mounted member in a state of being engaged with the nut mounting hole formed in the mounted member. In the caulking nut
The caulking fixing portion has a press-fitting fixing portion having the same diameter as the outer diameter of the nut main body portion and extending along the axial direction from one end side in the axial direction of the nut main body portion, and a press-fitting fixing portion having a smaller diameter than the press-fitting fixing portion and the press-fitting fixing portion. It has a substantially cylindrical pilot portion extending along the axial direction from one end side in the axial direction of the portion.
The press-fitting and fixing portion is formed with a plurality of recesses extending inward in the radial direction from an outer peripheral surface having the same diameter as the outer diameter of the nut body portion and extending along the axial direction along the circumferential direction. By being press-fitted into the mounting member, a part of the mounted member is accommodated in the recess and fixed in a state of being prevented from rotating with respect to the mounted member.
The pilot portion is formed so that the outer diameter on the axial tip surface side engages with the nut mounting hole of the mounted member, and the outer peripheral surface is the press-fitting fixing portion from the axial tip surface side. It is formed in a reverse taper shape that gradually decreases the outer diameter dimension toward one end side in the axial direction, and when the press-fitting fixing portion is press-fitted into the mounted member, the outer peripheral surface and the inner peripheral surface of the nut mounting hole A part of the attached member is accommodated in the gap, and the attached member is fixed in a state of being prevented from coming off.
A bottomed screw pilot hole is opened on the axial tip surface of the pilot portion.
The length of the caulked fixing portion along the axial direction is equal to or shorter than the plate thickness of the attached member.
A caulking nut that is characterized by that. A caulking fixing part is formed on one end side of the nut body in the axial direction.
The caulking fixing portion has a press-fitting fixing portion having the same diameter as the outer diameter of the nut main body portion and extending along the axial direction from one end side in the axial direction of the nut main body portion, and a press-fitting fixing portion having a smaller diameter than the press-fitting fixing portion and the press-fitting fixing portion. It has a substantially cylindrical pilot portion extending along the axial direction from one end side in the axial direction of the portion.
The press-fitting fixing portion is formed with a plurality of recesses along the circumferential direction that are recessed inward in the radial direction from the outer peripheral surface having the same diameter as the outer diameter of the nut body portion and extend along the axial direction.
The pilot portion is formed in a reverse taper shape in which the outer diameter dimension is gradually reduced as the outer peripheral surface is directed from the axial tip surface side toward the axial end end side of the press-fit fixing portion.
A bottomed screw pilot hole opens on the axial tip surface of the pilot portion.
In the cold heading method for caulking nuts,
The first cold heading process in which the round bar-shaped processed material is pressed in the first mold to form the axial tip side portion of the processed material in which the pilot portion is formed into a truncated cone shape.
The processed material taken out from the first mold is pressed in the second mold to form the nut main body portion and the press-fitting fixing portion in the processed material, and a small diameter is formed on the axial tip side of the processed material. The second cold heading process to form the shaft and
The first step of screw pilot hole machining for forming a pre-machined hole to open on the tip surface of the small-diameter shaft portion by pressurizing the machined material taken out from the second die in the third die, and the first step. 3 The second step of screw pilot hole drilling in which the machined material taken out from the mold is set in the fourth mold, and the screw pilot hole drilling rod is pushed into the premachined hole to form the screw pilot hole. And the third cold heading process with
The processing material taken out from the fourth mold is set in the fourth cold heading mold, a rod for forming a pilot portion is inserted into the opening end side of the screw pilot hole, and the small diameter shaft portion is used. The fourth cold heading process that forms the pilot part,
A cold heading method for caulking nuts, characterized by having. A caulking fixing part is formed on one end side of the nut body in the axial direction.
The caulking fixing portion has a press-fitting fixing portion having the same diameter as the outer diameter of the nut main body portion and extending along the axial direction from one end side in the axial direction of the nut main body portion, and a press-fitting fixing portion having a smaller diameter than the press-fitting fixing portion and the press-fitting fixing portion. It has a substantially cylindrical pilot portion extending along the axial direction from one end side in the axial direction of the portion.
The press-fitting fixing portion is formed with a plurality of recesses along the circumferential direction that are recessed inward in the radial direction from the outer peripheral surface having the same diameter as the outer diameter of the nut body portion and extend along the axial direction.
The pilot portion is formed in a reverse taper shape in which the outer diameter dimension is gradually reduced as the outer peripheral surface is directed from the axial tip surface side toward the axial end end side of the press-fit fixing portion.
A bottomed screw pilot hole opens on the axial tip surface of the pilot portion.
In the cold heading method for caulking nuts,
The first cold heading process in which the round bar-shaped processed material is pressed in the first mold to form the axial tip side portion of the processed material in which the pilot portion is formed into a truncated cone shape.
The processed material taken out from the first mold is pressed in the second mold to form the nut main body portion and the press-fitting fixing portion in the processed material, and a small diameter is formed on the axial tip side of the processed material. The second cold heading process to form the shaft and
A third cold heading step of pressurizing the processed material taken out from the second mold in the third mold to form the screw pilot hole that opens in the tip surface of the small diameter shaft portion.
The processing material taken out from the third mold is set in the fourth cold heading mold, a rod for forming a pilot portion is inserted into the opening end side of the screw pilot hole, and the small diameter shaft portion is used. The fourth cold heading process that forms the pilot part,
A cold heading method for caulking nuts, characterized by having.

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