JPH0525577B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is directed to a forging machine (former) that continuously presses a metal material from coarse to fine using a punch and a corresponding die to form a nut body. ) using
The present invention relates to a method for manufacturing a caulking nut having high hardness serrations on the protruding peripheral part that becomes the caulking part.

[Prior Art] A caulking nut is a special nut that can be fixed to a plastic plate or thin metal plate that cannot be welded or riveted. A serration process consisting of a spiral tooth profile or knurling is applied to the nut, but the conventional manufacturing method for caulking nuts is to use a multi-stage former to forge the nut body and then prepare the serration process separately. This is done using a dedicated processing machine.

Therefore, it takes time and effort to manufacture crimped nuts.
Since only the serration process cannot be automated in a consistent flow process, there was a problem in terms of productivity. However, in this type of serration processing, it is common to simply press a roll with grooves onto the circumferential surface of the material to form the stamp, and the surface remains rough in its metallographic structure, making it difficult to caulk. The necessary high hardness of serrations cannot be obtained, and therefore, when caulking is performed by forced pressing, there is a problem that firm fixation cannot be achieved.

[Object of the Invention] The present invention has been made in view of the problems of the conventional technology, and its purpose is to perform serration processing from heading to rolling using a multi-stage former. To perform the serration process necessary for caulking easily, quickly, and reliably in a continuous flow process in a continuous and fully automatic manner, and to form hard cortical serrations by suppressing overhang by narrowing the rolling die. The present invention aims to provide a method for manufacturing a swaged nut that allows for the following.

[Means for Solving the Problems] In order to achieve the above object, the method for manufacturing a caulking nut in the present invention includes a step of cutting a metal material into a certain length, and a process of cutting the cut material into horizontal rows. A plurality of dies and punches provided in correspondence with each die are sequentially forged to form a concentric tapered step on the disk-shaped protrusion on the head and the bottom surface of the seat. a step of forging a nut body formed by the nut body, a punching step of forming a hole to serve as a screw hole in the axial center of the nut body, and a step of reducing the diameter of the lower neck of the protruding peripheral portion to form the taper step portion. Step of extruding and forming a hard cortical serration on the outer periphery of the overhanging part of the taper step by pressing the serration forming part of the rolling die so as to suppress the overhang of the taper step at the same time as pressing the serration forming part of the rolling die so as to overhang the tapered step; These steps are performed sequentially and continuously.

[Embodiment] FIG. 1 is a plan view schematically showing the main parts of an apparatus for carrying out the present invention, and a cutting device 10 is shown on the left side of the figure.
A forging part 20 consisting of four stages of forging is provided in the middle, and a rolling mechanism part 30 is provided on the right side.

A cutting device 10 sends a metal material W made of a continuous wire to the tip end of a quill 12 by a feeding device 11, and cuts it into a constant length with a cutter 13 that moves across the tip end of the quill.

The forging section 20 includes a plurality of dies 21, 22, 23, 24 provided on the fixed side so as to be parallel to each other on the left and right.
and punches 26, 27, 28, 29 provided on the forging ram 25 side to correspond to the punches, respectively, and the forged materials (blanks) W', 1', 1 are placed in front of each die. ” from number 1 to number 2, 2
Transfer chucks 40 and 41 are provided which sequentially chuck the forging rams from No. 3 to No. 3 and send the forging ram to the next step every time the forging ram is operated.

The rolling mechanism 30 includes rolling dies 31 and 32 provided at final positions on the die side adjacent to the forging section in the same row and at the same interval, and a core body 33 provided on the punch side. One of the rolling dies 31 is a fixed die, and the other 32 is a movable die.

The movable die 32 is connected to gears 53, 54, 55, 56 from the main shaft 52 so as to be interlocked with the movement of the forging ram 25.
It is connected to the crank mechanism 51 via.

The core body 33 passes the nut body 1 supplied from the forging section through the rolling dies 31 and 3 when the forging ram 24 advances.
Hollow hole 1d of nut body 1 at the same time as pushing between 2
It fits inside and becomes the core shaft during rolling.

The nut body 1 has a hexagonal head 1 as shown in FIG.
A has a flange portion 1b and a disk-shaped peripheral portion 1c on its seat bottom surface, and a tapered portion 1c' that tapers downward is formed concentrically with the peripheral portion 1c.
A serration process is applied to c', and this serration process is carried out through four heading steps and 1d, and then supplied to the rolling section where it is applied.

As shown in FIG. 3, the material W' obtained by the cutting device is passed through punches 26, 27, 28 and dies 21, 22, 23 in the first to third forging steps b, c, and d.
Make nut materials 1′, 1″, 1″ by beating with
In the fourth step e, use a hole punch 29 and a die 2.
4 to form a hole 1d to form the nut body 1.

As shown in Fig. 4, this nut body 1 has a tapered stepped part 1c' that tapers downward (Fig. 4e) formed on the protruding peripheral part 1c in the third forging step (d in Fig. 3). After the hole is punched, the diameter of the lower neck 4 is reduced using rolling dies 31 and 32, and at this time, the taper step 1c' is suppressed from protruding to form an inverted triangular shape, and at the same time, teeth are formed or knurled on its outer periphery. Serrations 3 such as the following are formed. (Fig. 4 f). Therefore, the serrations 3 are formed of hard cortex in order to strongly suppress overhang during rolling.

[Function] The nut body 1 obtained in the fourth forging step e is conveyed to the rolling mechanism section 30 by a chuck 41, and is passed through a rolling die 31 in which the protruding peripheral part 1c and the tapered step part 1c' face each other from side to side.
It is supplied so as to be held between the two. When the punch moves forward, the core body 33 moves forward, inserts it into the hole 1d, and presses it, so that it is set immovably in all directions, such as front, back, left, and right (FIG. 3f). When the movable die 32 descends in this state, the protruding peripheral portion 1c of the nut body 1 sandwiched between both rolling dies is squeezed, and at the same time, a serration such as a spiral tooth shape, spur tooth shape, or knurling is formed on the tapered step portion 1c'. 3 is formed.

The nut body 1 that has been rolled is the rolling die 31,3.
When it is pushed out from between the two, it falls under its own weight and is recovered at a predetermined position via the chute 57. The nut body 1 thus obtained is then fed to a thread processing machine to form a thread 7 in the hollow hole 1d.

FIG. 5 shows a case in which the caulking nut obtained by the above method is driven into the tapered hole 61 of the thin plate 60 and fixed therein, and a bolt 62 is screwed thereto.

[Effects of the Invention] As described above, the present invention includes a step of cutting a metal material into a certain length, and a process of cutting the cut material into a plurality of dies arranged horizontally in a line and corresponding to each of the dies. A step of forging a nut body having a concentrically integrated concentrically tapered stepped part on a disc-shaped peripheral part on the head and the bottom surface of the nut by sequentially forging with a punch, and A hole punching process involves punching out a hole that will become a screw hole in the axial center of the cylindrical part. At the same time, the diameter of the lower neck of the protruding peripheral part is reduced and the tapered part is narrowed with a rolling die so that the tapered part protrudes. The process of pressing the serration forming part of a rolling die to suppress the overhang to extrude and form the hard cortex serrations on the outer periphery of the overhang of the tapered step part is carried out sequentially and continuously. The serration process, which had previously been performed, can be easily and reliably carried out in a continuous flow process using a multi-stage former.
Moreover, as a product, it is possible to provide a high-performance, high-quality caulking nut at a low cost because the surface layer is compressed to a high density, resulting in a hard cortex and highly hard serrations.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIG. 1 is a plan view showing the main parts of an apparatus for carrying out the method of the present invention;
Figure 2 is an enlarged sectional view taken from line A-A in Figure 1.
FIG. 3 is an enlarged plan view showing all the steps of the present invention, with some parts shown in cross section. FIG. 4 is a process diagram of an embodiment of the method of the present invention, and FIG. 5 is a sectional view showing an example of use of a swaged nut obtained by the method of the present invention. 1... Nut body, 1a... Head, 1b... Flange portion, 1c... Surrounding portion, 1d... Hole, 1c'...
Tapered step, 3...serration, 4...below neck,
31, 32...Rolled dice.

Claims (1)

[Claims] 1 The process of cutting a metal material into a certain length, and sequentially forging the cut material with a plurality of dies installed in a horizontal row and punches installed corresponding to each of the dies to form a head. A process of forging a nut body that has a concentrically integrated disc-shaped peripheral part and a tapered step part that tapers downward on its seat bottom surface, and punching a hole that will become a screw hole in the axial center of the nut body. and serration forming with a rolling die to reduce the diameter of the bottom of the protruding peripheral part and narrow it with a rolling die so that the taper step protrudes, and at the same time to suppress the protrusion of the taper step. A method for manufacturing a caulking nut, characterized in that the steps of pressing the parts together to extrude and form a hard cortex serration on the outer periphery of the overhanging part of the tapered stepped part are successively carried out.