JPH0914230A - Rivet and manufacture thereof - Google Patents

Abstract

PURPOSE: To provide a rivet capable of preventing the barrel bulge or bend of a shank section, and a rivet manufacturing method for providing such a rivet by a large quantity and inexpensively. CONSTITUTION: Regarding a rivet 1 having a head 2 and a shank 3, nickel plating is applied to the rivet 1 cold pressed and molded from a raw material. Also, a knurled section 7, a streak or a plating separation section such as irregularities are formed on the barrel section 6 of the shank 3 of the rivet 1, and the barrel section 6 is carburized for hardening. Thus, a rivet caulking work becomes free from the barrel bulge or the bend of the section 6. In addition, when the rivet 1 is caulked to a workpiece, the workpiece does not become afloat, and can be firmly caulked. In addition, rivet alignment is not required, and a time required for a riveting work is substantially shortened, thereby providing suitability for mass production. Also, a raw material of high hardness is not required at a cold pressing and molding process, and a molding tool is less abraded. At the same time, service life of the tool is extended.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a leg length rivet in which the legs are relatively long with respect to the head, and in particular, the torso of the legs is swollen or bent during the rivet caulking work. Without rivets and a method of manufacturing such rivets.

[0002]

2. Description of the Related Art Conventionally used rivets have a head and legs formed by pressure forming on a material of a predetermined size, and the desired rivet can be obtained by lengthening or shortening the leg length according to the application. It has gained. The rivets thus obtained are
If the legs are relatively short, there will be no problem, but if they are long, the body of the legs will bulge or bend during caulking work, causing improper caulking. . In order to solve this, rivets are currently manufactured by adding the following steps to improve the strength of the body.

That is, in general, such a rivet has, as shown in FIG. 4 and FIG.
10, first, as a preforming, the head and legs are molded to a specific shape to obtain a semi-finished product, and subsequently, as a final forming, the head 102 and the legs 103 are press-formed into a predetermined size, and a hollow hole is formed at the tip of the legs. 104 is bored. This preforming and finish forming are usually referred to as forging forming step 110, and the rivet 101 obtained by this forging forming step 110 is subsequently subjected to the annealing treatment step 113 in the leg portion 103.
The tip of the is annealed. Usually, this annealing treatment is performed by the rivet 101 manufactured in the forging forming step 110.
Are supplied in an aligned state with the head 102 on top and the legs 103 hanging down, and the tips of the legs are heated for a predetermined time by using a combustion device (not shown) such as a single burner, and then naturally cooled. The process is performed by performing. After that, the rivet 101 that has been annealed is subjected to a finish plating treatment step 11
4 and subjected to a desired finishing treatment such as plating, as shown in FIG. 4, a rivet 1 having a relatively long leg length as a product.
01 is completed. Then, the rivet 101 is inserted into the caulking hole 121 of the work 120 and caulking.

Further, instead of such a process, as shown in FIG. 5, the shape of the rivet itself is such that the body portion 106 fitted in the caulking hole 121 of the work 120 is made thicker than the tips of the leg portions 103, and the head portion 102 is made thicker. A striking force is applied to the tip of the leg portion 103, and the tip end of the leg portion 103 is expanded and crimped until the striking force is applied to the body portion 106 during caulking work to cause deformation such as swelling or bending of the body portion. A rivet 101 having a stepped leg portion 103 is also used.

[0005]

However, when the rivets are crimped, the leg ends are not swollen or bent as shown in FIG. 4 when the rivet crimping work is annealed. However, when the rivet is annealed, the rivet must be aligned in a so-called neck hanging state in which the head is up and the legs are hanging down, and moreover the entire circumference of the tip of the legs must be heated. This process requires a long time and is not suitable for mass production. Also, in this press forming, since the forming tool used has a relatively high hardness of the material of the rivet, the material is expensive and the tool used during the press forming is likely to wear, resulting in a shorter tool life. Was there.

In order to solve this problem, the shape of the rivet itself has a stepped shape with a thick leg and a thin tip, which prevents bulging or bending of the body during caulking work. Since it is necessary to make the legs stepped in forming, there are problems such as a new step of making the legs stepped and a large amount of material required in the work in this forging forming process. .

A first object of the present invention is to solve the above problems and to provide a rivet which prevents the leg from bulging or bending in the caulking work of a rivet having a relatively long leg. A second object of the present invention is to provide a rivet manufacturing method for a rivet having a long leg length, in which a large amount of rivets without bulging or bending can be obtained inexpensively during rivet crimping work.

[0008]

SUMMARY OF THE INVENTION A first object of the present invention is to:
A rivet 1 comprising a head portion 2 and a leg portion 3, wherein a rivet 1 pressed from a material is nickel-plated, and a body portion 6 of a leg portion 3 of the rivet 1 is provided with knurls 7, streaks or irregularities. This can be achieved by forming a plated-off portion and providing the body portion 6 with the carburized rivet 1.

A second object of the present invention is to form a rivet 1 consisting of a head 2 and a leg 3 in a press forming step 10 on a material having a predetermined size, and to form a nickel plating step 1 on the rivet 1.
1 to perform nickel plating, and then, in a rolling step 12, the body 6 of the leg portion 3 is subjected to rolling processing such as knurling 7, streaks or irregularities to remove the nickel plating of the body 6, and thereafter, This is achieved by providing a method of manufacturing the rivet 1 in which the rivet 1 is carburized in the carburizing process 13 and the body 6 of the leg 3 is hardened.

[0010]

In operation, the rivet 1 is carburized at the portion where the nickel plating has been peeled off in the previous step by previously forming knurls 7 or streaks on the leg 3 of the rivet 1 or forming irregularities. When the leg portion 3 is inserted into the caulking hole 21 first, and then the head portion 2 of the rivet 1 is pressed, the tip of the leg portion 3 of the rivet 1 is expanded and the workpiece 20 is opened.
Caulk. At this time, since the body portion 6 of the leg portion 3 is hardened, the body does not bulge and a gap is not formed between the head portion 2 of the rivet 1 and the work 20. Squeeze 20

On the other hand, the rivet 1 is manufactured by forming a rivet 1 composed of a head 2 and a leg 3 in a press forming step 10 on a material having a predetermined size, and then nickel-plating the entire rivet 1 in the next step. . Next, the leg portion 3 of the rivet 1 coated with the nickel plating is rolled in a rolling process 12 such as rolling, streak or unevenness to remove the plating of the body portion 6 of the leg portion 3. As a result, the ground surface of the rivet 1 appears again in the plated-off portion of the leg portion 3. Therefore, when the entire rivet 1 is carburized in the next carburizing step 13, the body portion 6 from which the plated metal has been peeled off is carburized. On the other hand, the portion covered with nickel plating is not carburized, and the hardness of the material remains unchanged. As a result, during caulking work, the body 6 does not swell or bend, and the tips of the legs 3 are reliably expanded and the work 20 is caulked with the rivet 1.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, 1 is a rivet, and 2 is a head of the rivet 1. A leg portion 3 having a diameter smaller than the head portion is formed on the head portion 2, and a hollow hole 4 forming an expanded portion of the rivet 1 is formed at the tip of the leg portion 3. The entire surface of the rivet 1 is plated with nickel, and the neck 5 and the hollow hole 4 continuous with the head 2 are provided.
In order to remove the nickel plating, a knurled portion 7 such as crocheted or flat mesh, a plating stripping portion is formed by streaks or irregularities in the portion of the body portion 6 of the leg portion 3 between and. The plated-off portion is carburized so that the body portion 6 is hardened. Further, the whole is plated with chrome, nickel, zinc or the like for finishing as required to form a rivet 1 as a product.

Therefore, in the caulking operation, the rivet 1 is caulked in the work 20 as shown in FIG.
When it is inserted into the inside and the head 2 is pressed with a punch (not shown), the hollow hole 4 in the lower part of the leg 3 of the rivet 1 is expanded by being acted on by an expanding anvil (not shown). It At this time,
Since the body 6 of the rivet 1 is carburized and hardened, the body 6 does not swell or bend even if the striking force at the time of the caulking work acts on the leg 3, and the tip of the leg 3 is prevented. Is surely expanded. As a result, the caulking hole 2 of the work 20
The vicinity of 1 rises to the seating surface side of the head 2, and the rivet 1 is caulked without a gap between the seating surface of the head 2 and the work 20.

On the other hand, such a rivet 1 can be manufactured by the process shown in FIG. 3, and 10 is a raw material (not shown).
It is a press forming step of forming the rivet 1 including the head 2 and the leg 3. This forging forming step 10 is preforming to obtain a rivet blank (not shown) of a specific shape of the head 2 and the leg 3 from a material of a predetermined length in advance, and further forging the rivet blank obtained by the preforming. In addition, it consists of finish molding to obtain a rivet 1 having a predetermined size and a hollow hole 4. After the press forming step 10, a nickel plating treatment step 11 is arranged, and the entire rivet 1 obtained in the press forming step 10 is subjected to nickel plating as a base treatment.

After this processing step, the leg portion 3 of the rivet 1 is
A rolling process 12 for peeling and removing the nickel plating is arranged on the body 6 of the body 6, and in this process, the body 6 is subjected to a rolling process to form knurls 7 to form this portion. The nickel plating of is peeled off, revealing the background of the material. In the rolling process 12 of this embodiment, the rolllets 7 are formed by rolling. However, instead of this, streaks or irregularities may be formed by rolling, and if the plating is peeled off in the rolling process 12. Good.

The rolling step 12 is followed by a carburizing step 13. In this step, the carburizing process is performed on the background of the body 6 from which the plating has been peeled off. After this step, there is provided a finish plating treatment step 14 for performing finish plating of chromium, nickel, zinc or the like necessary for the rivet 1 as a product.

In such a manufacturing process, in a press forming process 10, a rivet 1 of a predetermined size including a head 2 and a leg portion 3 narrower than the head 2 is press formed on a material previously cut into a predetermined size. To be done. Thereafter, the rivet 1 is entirely nickel-plated in the nickel plating treatment step 11. This nickel plating is for preventing carburization to a portion where carburizing is unnecessary in the carburizing 13 as a post process.

In this way, the rivet 1 which is entirely plated with nickel is transferred to the rolling step 12, and rolling processing such as knurling 7, streaks or unevenness is added,
The nickel plating is peeled off from the body portion 6 of the leg portion 3. As a result, the rivet 1 showing the background is transferred to a carburizing step 13 and carburizing is performed. This carburizing process is performed on the entire rivet 1, but nickel plating is applied except for the body portion 6 from which the plating of the leg portion 3 has been peeled off, so that the body portion 6 has high hardness, but this portion is Except for this, the hardness of the rivet 1 does not increase as it is, and the rivet 1 having the body portion 6 having high strength is obtained.

After that, the rivet 1 is moved to a finish plating treatment step 14, where necessary finish plating is applied as a product to obtain a highly reliable product. In this embodiment,
In the rolling process 12, the rolling process is performed to peel off the nickel plating on the body portion 6, but instead of this, the nickel plating on the body portion 6 may be peeled off by shot blasting or the like. However, if the material of the rivet 1 has a bare surface, the plating removal means is not limited to this.

[0020]

As is apparent from the above-described embodiments, the present invention is a rivet 1 having a head 2 and legs 3, and the rivet 1 press-formed from a material is nickel-plated. The rivet 1 is formed by carburizing the rivet 1 by forming a knurled portion, a stripped portion such as streaks or irregularities on the body 6 of the leg 3 of the rivet 1, and carving the body 6. No bulging or bending. Moreover, when the rivet is caulked to the work, the work is firmly lifted without floating. Further, since it is not necessary to align the rivets, the time required for the processing is significantly shortened, and the rivets suitable for mass production can be obtained at low cost.

Further, a press forming step 10 is performed on a material having a predetermined size.
The rivet 1 including the head 2 and the leg 3 is formed by using the rivet 1, and the rivet 1 is nickel-plated in the nickel plating treatment step 11. Subsequently, the body 6 of the leg 3 is rolled in the rolling step 1
2, the knurling 7, streaks or irregularities are rolled to remove the nickel plating of the body 6, and then the rivet 1 is carburized in the carburizing process 13 to form the legs 3
Since it is a method of manufacturing the rivet 1 in which the body portion 6 of the rivet 1 is hardened, it is not necessary to use a material having high hardness in the press forming for obtaining this rivet, and the wear of the forming tool to be used is reduced and the life is also shortened. long. Further, even if the rivet itself does not have a stepped shape in which the body of the leg is thick and the tip is thin, it is possible to prevent the body from bulging or bending during the crimping work, so that the number of steps is reduced in the forging process. The effect is obtained.

[Brief description of the drawings]

FIG. 1 is a sectional front view showing an enlarged main part of a rivet according to the present invention.

FIG. 2 is an enlarged cross-sectional front view of an essential part showing a crimped state of the rivet of the present invention.

FIG. 3 is a process chart showing a manufacturing process of the present invention.

FIG. 4 is a sectional view of a main part of a rivet and a work showing a conventional example.

FIG. 5 is a cross-sectional front view of essential parts of a rivet and a work showing another conventional example.

FIG. 6 is a process drawing showing a manufacturing process of a conventional example.

[Explanation of symbols]

 1 Rivet 2 Head 3 Leg 4 Hollow Hole 5 Neck 6 Body 7 Knurling 10 Press Forming Process 11 Nickel Plating Process 12 Rolling Process 13 Carburizing Process 14 Finish Plating Process 20 Work 21 Caulking Hole

Claims (4)

[Claims] 1. A rivet 1 comprising a head portion 2 and a leg portion 3, wherein a rivet 1 pressed from a material is nickel-plated, and a body 6 of a leg portion 3 of the rivet 1 is plated with a plated-off portion. A rivet characterized in that the plated-off portion is carburized. 2. The rivet according to claim 1, wherein the plated-off portion is a knurl 7, a streak, or an unevenness. 3. A rivet 1 consisting of a head 2 and a leg 3 is formed in a material having a predetermined size in a press forming step 10, the rivet 1 is nickel plated in a nickel plating treatment step 11, and then the leg is formed. In the rolling step 12 of the body 6 of the part 3, rolling processing is applied to remove the nickel plating of the body 6, after which the rivet 1 is carburized in the carburizing step 13 to form the body of the leg 3 A method of manufacturing a rivet, characterized in that the part 6 is cured. 4. The method of manufacturing a rivet according to claim 3, wherein the rolling step is a rolling process for forming knurls 7, streaks or irregularities.