JP2003260532A - Apparatus and method for manufacturing bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for manufacturing a bolt which can reliably and efficiently manufacture a double screw bolt in which double screw threads different from each other in pitch are provided so as to cross each other. <P>SOLUTION: A coarse thread forming protrusion 15, a coarse thread forming groove 17, and a fine pitch thread forming protrusion 16 are provided in a die 14 for form rolling. The pitch of the fine pitch thread forming protrusion 16 is half of the pitch of the coarse thread forming protrusion 15. Therefore, the fine pitch thread forming protrusion 16 extends so as to obliquely cross the coarse thread forming groove 17. Since the coarse external thread forming protrusion 15 and the fine pitch external thread forming protrusion 16 are provided in a combined state in one die 14, a slip phenomenon between the die 14 and the bolt 1 can be avoided. Consequently, a double screw bolt having a high level of nut locking function can be manufactured with high efficiency and stable quality. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for manufacturing a multi-threaded bolt having a plurality of threads (male threads) having different pitches formed on the outer circumference in a crossed state (here). The bolt means that a male thread is formed on at least a part of the shaft, regardless of the presence or absence of the head or the size).

[0002]

2. Description of the Related Art In order to prevent or suppress loosening of nuts when fastening various works with bolts and nuts,
The main nut that contacts the work and the lock nut that contacts the main nut are fastened by the double nut method.

In order to further improve the loosening prevention function by fastening the double nut, the pitch of the screw in the lock nut is made smaller than the pitch of the main nut.

As an example thereof, Japanese Patent Laid-Open No. 10-26512
In the gazette, a portion of the bolt into which the main nut is screwed has a large diameter, and a portion into which the lock nut is screwed has a small diameter to form a thread having a fine pitch in the small diameter portion. It is described that a washer is interposed between the lock nut and the lock nut.

As another example, Japanese Patent Laid-Open No. 7-103221 (see especially FIG. 4) discloses that the entire thread portion of a bolt has a large pitch thread for screwing a main nut and a small pitch for screwing a lock nut. It is described that it is formed as a double screw (or a double thread) that intersects with the screw thread of.

Further, in Japanese Patent Laid-Open Nos. 2001-99120 and 2001-252730, a portion of a bolt into which a lock nut is screwed is described in Japanese Patent Laid-Open No. 7-
It is described that a double threaded portion similar to that of the 103221 publication is used.

Further, in Japanese Patent Laid-Open No. 2001-252730, as a method for forming a double threaded portion on a bolt, a die for forming threads with a large pitch,
Using a die for forming a small pitch, by rolling the bolts on both dies at the same time to form threads of different pitches, and forming a thread of a large pitch first by rolling or cutting. Then, a method of rolling or cutting a thread having a small pitch is described.

[0008]

[Patent Document 1] Japanese Patent Laid-Open No. 10-2651
The one in which the diameter of the portion into which the main nut is screwed in and the portion in which the lock nut is screwed in as in Japanese Patent Publication No. 2 has the advantage that the thread is easily machined, but the bolts must be formed with different diameters. There is a problem in that the number of man-hours required for processing the material is increased because it has to be done, and that the lock nut is smaller than the main nut, so that a washer to be interposed between both nuts is indispensable.

On the other hand, JP-A-7-103221, JP-A-2001-99120, and JP-A-2001-25.
When the threaded portion of the bolt is formed into a double screw type as in Japanese Patent No. 2730, it is possible to prevent an increase in the number of processing steps of the bolt, and since the main nut and the lock nut can be of the same size, the washer It is more realistic because it has the advantage of not requiring.

Particularly, as shown in FIG. 4 of Japanese Patent Laid-Open No. 7-103221, if the entire screw portion is formed as a double screw, the main nut and the lock nut can be screwed into any position of the screw portion, so that the workpiece can be screwed. It can be said that it is more versatile because it can accurately respond to the difference in thickness.

Although the bolt formed in such a manner that the threads having different pitches are crossed with each other is excellent as the product itself, the quality and efficiency are improved by the manufacturing method described in Japanese Unexamined Patent Publication No. 2001-252730. There was a problem with this, which was the cause of hindering commercialization.

That is, among the manufacturing methods described in Japanese Patent Application Laid-Open No. 2001-252730, a method of simultaneously forming two thread threads by rolling using two types of dies, and a thread having a large pitch are first prepared. The method of forming threads with a small pitch by rolling after forming is that it is extremely difficult to accurately process threads with a small pitch due to the occurrence of a slip phenomenon of the die, and in the end, it is practically used. It was not possible to secure the quality to endure.

Further, the method of forming a thread having a large pitch and then forming a thread having a small pitch is considered to be able to maintain the quality, but it must be done manually by using a lathe. However, there is a problem that profitability is poor because the manufacturing efficiency is extremely low.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to mass-produce a double-screw bolt having a high locking function with stable quality.

[0015]

The inventors of the present application have been engaged in the development of fasteners such as bolts and nuts for many years, and have a wealth of knowledge and experience in bolt manufacturing equipment. There is. Then, based on such knowledge and experience, further research and testing were repeated to complete the present invention.

That is, according to the first aspect of the present invention, a plurality of threads having different pitches are crossed with each other by a rolling method using a die such as a flat die, a round die, or an arc-shaped die. An apparatus for producing a formed multi-screw bolt, wherein the die is formed with a group of protrusions (or irregularities) for forming the plurality of threads on the bolt crossing each other. ing.

In the rolling die, a large number of concavo-convex stripe groups that mesh with the threads of the bolt are formed. In the die of the present invention, for example, a bolt having two threads is formed. In the case of the die for manufacturing, the ridges and grooves for forming the threads with a large pitch and the ridges and grooves for forming the threads with a small pitch intersect and extend.

Since the interval between the projections and depressions for forming threads on the bolt is the same as the pitch of the threads, the number of projections and depressions for forming threads with a large pitch is inevitably ( The number of ridges and valleys for forming threads with a smaller pitch is larger than the number of threads.

By the way, in Japan, the JIS standard and the ISO standard are prevailing as the standards for screws, and it is preferable to conform to these standards from the viewpoint of enhancing versatility.

Therefore, according to the invention of claim 2, in claim 1, the plurality of threads having different pitches on the bolts are coarse and fine threads defined in JIS standard or ISO standard. Then, the die is formed so that the coarse male screw forming protrusion and the fine male screw forming protrusion intersect and extend.

According to the third aspect of the invention, in order to manufacture a multi-threaded bolt in which a plurality of threads with different pitches are formed in a state of intersecting each other by a cutting method using a cutting tool such as a cutting tool or a chaser. In the device of, the rotating means for rotating the material of the bolt around its axis, a plurality of blades for individually processing a plurality of threads with different pitches, and each blade according to the pitch of the threads A plurality of moving means for moving the material in parallel therewith are provided.

According to the invention of claim 3, a plurality of threads having different pitches are formed by a molding method such as a casting method using a metal material, a die casting method or a lost wax method, or an injection molding method using a synthetic resin material. Is a device for manufacturing a multi-screw bolt formed in a state of intersecting with each other, wherein a molding die is formed with a group of protrusions for forming the plurality of threads on the bolt intersecting each other. ing.

The present invention also includes a method of manufacturing a bolt, which uses the apparatus described in any one of claims 1 to 3 in which the material shaft has the same outer diameter and the same pitch. The feature is that a plurality of different threads are simultaneously formed in an overlapping state.

[0024]

According to the first and second aspects of the present invention, the bolt (more accurately, the intermediate product of the bolt) can be formed into a plurality of strips having different pitches by one rolling process using a die. The thread can be reliably formed.

By the way, since a plurality of threads having different pitches intersect each other, a die for forming a thread having a large pitch and a die for forming a thread having a small pitch are provided as in the prior art. If you use, the ridges (tooth) of the die for forming threads with small pitch will hit the inclined surface of threads with large pitch,
Therefore, a slip phenomenon occurs between the die and the bolt,
It has been extremely difficult to form small pitch threads.

On the other hand, according to the present invention, for example, in the case of manufacturing a double screw type bolt, the ridge (and groove) for forming the thread having a large pitch is formed on the die.
Group and the group of ridges for forming threads with a small pitch are integrally formed in a state where they intersect (or are in a composite state). Therefore, it is possible to surely bite into the bolt, and therefore, it is possible to reliably form a plurality of threads extending crossing each other on the bolt by a simple rolling process.

Therefore, according to claim 1 and claim 2,
A bolt having a high nut loosening prevention effect can be manufactured efficiently and with stable quality by the rolling method. According to the second aspect, since the standardized nut can be used, there is an advantage that the versatility is high.

According to the third aspect of the present invention, since the threads having different pitches can be simultaneously cut on the outer peripheral surface of the bolt, a bolt having a high nut locking effect can be efficiently manufactured even in the cutting method. be able to. In this case, it is preferable to use a chaser as a blade in terms of durability.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the drawings. To facilitate understanding of the embodiment, the structure of a bolt will be described first.

(1). Description of Bolt (FIGS. 1 to 5) FIG. 1 is a view showing a usage state of a hexagon headed bolt manufactured by the apparatus according to the present invention. The double nut of the lock nut 3 and the lock nut 3 is used for fastening the work 4.

As shown schematically in FIG. 2 (A), as an example of outward threads (threads) having different pitches on the entire threaded portion of the bolt 1, a JIS standard or ISO standard coarse thread is used. Two threads of thread 5 and fine thread 6 are formed. Coarse thread 5 is conceptually drawn with a thick line, and fine thread 6 is conceptually drawn with a thin line. ing.

2 (B) and 2 (C), the relationship between the coarse thread 5 and the fine thread 6 is shown for convenience. The pitch of the fine thread 6 is half the pitch of the coarse thread 5.

Coarse inward threads 7 are formed on the inner circumference of the main nut 2, and fine inward threads 8 are formed on the inner circumference of the lock nut 3.

In FIG. 3A, the threaded portion of the bolt 1 is
The front view seen from the direction, (B) is a BB view of (A), and FIG. 4 is a partial plan sectional view (the cross section of the thread is omitted).
As can be easily understood from these figures, the fine thread 6 extends obliquely across the coarse thread 5.

Coarse thread grooves 9 are formed between the adjacent coarse threads 5, and fine thread grooves 10 are formed between the adjacent fine threads 6. . Therefore, when the two threads 5 and 6 cross each other, to be precise, it means a state in which the fine thread groove 10 extends diagonally across the coarse thread 5. Further, the fine thread 6 and the coarse thread 5 overlap each other.

The pitch of the fine thread 6 is equal to that of the coarse thread 5.
Since it is half the size of the pitch, the fine thread 6 crosses the coarse thread 5 diagonally every 360 ° in the circumferential direction. For this reason, the threaded portion of the bolt 1 is formed with a group of fine threaded grooves 10 arranged regularly in the axial direction, and this appears in the threaded portion of the bolt 1 as a fixed pattern.

FIG. 5A is a partial development view showing the relationship between the coarse thread 5 and the fine thread 6, and FIG.
(H) is a cross-sectional view of the corresponding part in (A). As can be seen from this figure, the fine thread groove 10
Erodes the coarse thread 5 while gradually changing its cross-sectional area.

In FIG. 5A, the fine thread 6 is shown to extend over the entire circumference, but this is for convenience of understanding, and in practice, Only the thread groove 10 appears as the thread 6 of.

Further, in FIG. 3, for convenience of drawing, the threads 5 and 6 are drawn in a complete triangle, and the nuts 2 and 3 are drawn.
The inward threads 7 and 8 of the bolt and the threads 5 and 6 of the bolt 1 are drawn in close contact with each other, but in reality, the top surfaces of the threads 5, 6, 7 and 8 are narrow. Is a flat surface or curved surface, and the valley bottom is also a narrow flat surface or curved surface,
In addition, there is a small gap between the flanks of the threads that mesh with each other.

Needless to say, the height of the fine thread 6 is half the height of the coarse thread 5, and the outer diameter of both the threads 5 and 6 is essentially the same. Are the same (or almost the same), but the heights of the threads 5 and 6 are low in the portion where the fine thread groove 10 is formed.

(2). First Embodiment (FIGS. 6 to 13) Next, a first embodiment in which the present invention is applied to a rolling type manufacturing apparatus will be described with reference to FIGS. 6 to 13.

.. Outline FIG. 6 is a separated front view, FIG. 7 is a side view in the middle of the rolling process, and FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 7. As shown in these drawings, the rolling device of the present embodiment is shown. Has a pair of flat dies 14 as in the conventional case. By sandwiching the material bolt 1 between the flat dies 14 and moving the flat dies 14 relative to each other, the coarse thread 5 and the fine thread Threads 6 are formed.

Generally, one of the flat dies 14 is fixed and the other is movable (moving), but both flat dies 14 can be moved together.

.. Outline of Die Next, the structure of the flat die 14 will be described with reference to FIGS. Since both flat dies 14 are vertically symmetrical and have essentially the same sectional structure, the die 14 arranged below in FIGS. 6 and 7 will be described as an example.

In FIG. 9, (A) is a partial plan view conceptually displayed, (B) is a partially enlarged view of (A), and (A) of FIG. 10 is a partial plan view of the flat die 14. (B) ~
(H) is a sectional view of the corresponding part in (A), FIG. 11 is a partially cutaway perspective view, FIG. 12 is a schematic side view, and FIG.
3 is a sectional view in the middle of processing.

As shown in FIG. 9 (A), bolts (to be exact, intermediate products of the bolts) of the flat die 14 and the head 1 is attached to the material shaft.
(for which a is formed), a group of protrusions 15 for forming coarse thread for the sake of convenience, and a fine thread for forming the fine thread for convenience, which are indicated by a thin line, are provided on the surface in contact with the shaft. A group of ridges 16 is formed.

The inclination angle θ1 of the coarse thread forming projection 15 with respect to the moving direction of the flat die 14 (direction of arrow A) is the same as the lead angle of the coarse thread 5 of the bolt 1,
The inclination angle θ1 of the fine thread forming projection 16 with respect to the traveling direction of the flat die 14 is determined by the fine thread 6 of the bolt 1.
Is the same as the lead angle.

In addition, adjacent coarse thread forming protrusions 15
P1 is the same as the pitch of the coarse thread 5 of the bolt 1, and the pitch P2 of the adjacent fine thread forming protrusions 16 is the same as the pitch of the fine thread 6 of the bolt 1. Therefore, there are two fine thread forming protrusions 16 corresponding to one coarse thread 5.

Since θ2 is half the angle of θ1, the fine thread forming projection 16 and the coarse thread forming projection 15 inevitably intersect with each other. The material diameter of the bolt 1 is D0, the outer diameter of the thread 5 on both sides is D1, and the root diameter of the thread 5 on the side is D2.
Then, in the traveling direction of the flat die 14, (π · D
The coarse thread forming projection 15 and the fine thread forming projection 16 intersect each other as the distance of 0) is increased.

The length of the flat die 14 in the traveling direction is generally set to be 4 to 5 times the circumference of the bolt 1.
Therefore, the group of the fine thread forming projections 16 extends obliquely across the group of many coarse thread forming projections 15 one after another.

.. Detailed Cross-sectional Shape of Die As specifically shown in FIG. 10, coarse thread forming ridge 1
Reference numeral 5 is a shape (triangular section in cross section) that fits snugly to the thread groove 10 of the coarse line, and inevitably, between adjacent ridges 15, a cross-sectional shape that fits tightly to the thread 5 of the coarse line. Grooves 16 for forming a coarse thread (in the shape of an inverted triangle) are formed.

In the drawing, for convenience, the ridges 15 and 16 and the groove 1
7 is shown as an acute angle, but actually the ridges 15, 16
The top surface of is formed in an extremely narrow flat or curved surface,
The bottom surface of the groove 17 is also formed in a flat shape or a curved surface with an extremely narrow width.

The fine thread forming projection 16 extends obliquely so as to fill the coarse thread forming groove 17.

As can be understood from FIGS. 10 (B) to 10 (D), the fine thread forming ridges 16 are arranged such that one of the adjacent coarse thread forming ridges 15 is inclined to the other. It extends so as to gradually deviate toward the inclined surface of the thread 15 for forming threads. This is because the inclination angles θ1 and θ2 of the coarse thread forming projection 15 and the fine thread forming projection 16 are different.

As shown schematically in FIG. 12, the shaft portion of the bolt 1 is sandwiched between one end of the fixed side flat die 14 and the other end of the movable side flat die 14, and the movable side flat die 14 is sandwiched. By moving 14, the screw threads 4 and 5 are formed on the shaft portion of the bolt 1 by plastic deformation. However, an appropriate range near one end of the fixed die 14 and the other end of the movable flat die 14 are formed. The appropriate range is formed as the chamfered portion 14a that is inclined so that the distance between them is widened.

.. Rolling process As shown in FIG. 13, a material bolt 1 is sandwiched between a pair of flat dies 14 and both flat dies 14 are moved relative to each other, whereby a coarse thread 5 and a fine thread 6 of the bolt 1 are formed. And can be formed at the same time.

In this case, the coarse thread forming ridge 15 and the fine thread forming ridge 16 bite into the smooth outer peripheral surface of the bolt 1, so that between the flat die 14 and the bolt 1. Since the relative slip phenomenon of does not occur,
As a result, the coarse thread 5 and the fine thread 6 can be reliably formed only by the rolling process.

It should be noted that, in a state where the threads 5, 6 are formed on the bolt 1, the space between the top surface of the coarse thread 5 and the bottom surface of the coarse thread forming groove 17 in the flat die 14 is small. It may be set so that a slight gap is left. That is, the groove 17 of the projection 15 for forming coarse threads in the flat die 14
The depth dimension may be slightly larger than the height dimension of the coarse thread 5.

Then, when the meat of the material bolt is plastically deformed by the flat die 14 to form the coarse thread 9, the clearance of the meat can be provided, so that the bolt 1 is easily plastically deformed. The durability of can be improved.

As in this embodiment, two flat dies 14 are used.
Both of them are configured as a composite die in which a group of coarse thread forming projections 15 and a group of fine thread forming projections 16 are formed, and the fine threads 6 are formed by both flat dies 14. Therefore, the length of the flat die 14 (length in the moving direction)
Even if the length is short, not only can it be machined efficiently, but the same force acts on the material bolt 1 from the opposite side across the axis.
There is an advantage that the force during plastic deformation is well balanced and the durability of the flat die 14 is also improved.

(3). Second Embodiment (FIG. 14) In the above-described first embodiment, both the pair of flat dies 14 are provided with a group of coarse thread forming projections 15 and a fine thread forming projection. 1
Although it was a composite die in which groups of 6 were formed,
As shown as a second embodiment in FIG.
Can be a composite die, and the other flat die 14 can be a simple die in which only a group of coarse thread forming projections 15 is formed.

(3). Third Embodiment (FIG. 15) The present invention is a plurality of round dies (rotary dies) 19
It can also be applied to a rolling device using. An example thereof is shown in FIG. 15 as a third embodiment. Of these, (A) shows an example using two round dies 19,
(B) and (C) show three round dice 19,1.
This is an example using 9 '.

In (A) and (B), all round dies 19
The coarse thread forming ridge 15 and the fine thread forming ridge 1
6 and 6 are formed as a composite die, and in (C),
Two of the three round dies are used as the composite die 19, and the other one is used as the simple round die 19 'in which only the coarse thread forming projections 15 are formed. As can be understood from (C), when a round die is used, in the present invention, at least one of the plurality of round dies may be a composite die.

(D) shows an example applied to a rolling device using a fan-shaped die 26 having an arcuate outer circumference and a die 27 having an arcuate inner circumference.

(4). Fourth Embodiment (FIGS. 16 to 17) FIGS. 16 and 17 show a fourth embodiment in which claim 3 is embodied. 16 is a schematic plan view, and FIG. 17 is FIG.
6 is an XVII-XVII view of FIG.

In this embodiment, the bolt 1 is formed with the coarse thread 5 and the fine thread 6 at the same time by cutting, and a chuck provided on the rotary shaft for gripping the head 1a of the bolt 1 is used. 20 and a center roller 21 for preventing contact
The coarse thread forming chaser 22, the fine thread forming chaser 23, the moving heads 24 and 25 to which the respective chasers 22 and 23 are fixed, and the heads 24 and 25 approaching and separating from the bolt 1. A pair of first moving means (not shown) for vertically feeding the heads 24, 25 to the bolt 1
And a pair of second moving means (not shown) for laterally feeding in a direction parallel to the axis of the.

Since both chasers 22 and 23 are arranged on both sides of the axial center of the bolt 1, the cutting blades are turned upside down.

In this embodiment, the lateral feed speed V2 of the fine thread thread forming chaser 23 is well half the feed speed V1 of the coarse thread thread forming chaser 22. Therefore, by rotating the material bolt 1 while vertically feeding both chasers 22 and 23,
Coarse threads 5 and fine threads 6 can be simultaneously cut on the bolt 1.

The cutting by both chasers 22 and 23 may be set to be performed at the same time, or the cutting start timing may be shifted so that the cutting by either of the chasers 22 and 23 is performed first.

It is also possible to cut the double thread by fixing either one of the two chasers 22 and 23, moving the bolt 1 in the axial direction, and moving only the other chaser. it can. As a blade for cutting the threads, it is possible to use a rotary cutter instead of a chaser or a bite.

(5) Fifth Embodiment (FIG. 18) By the way, in the case of processing a screw thread by cutting, if the complete screw portion is processed by only one feed of a cutting tool such as a chaser or a cutting tool, the cutting tool is burdened. And the durability of the blade becomes low.

Therefore, in the fifth embodiment shown in FIG. 18 as a modified example, the rough-finishing chasers 22a and 22a are used as the coarse thread forming chaser and the fine thread forming chaser.
3a and two chases 22b and 23b for final finishing are prepared, and a pair of chasers 22a to 23b are laterally fed with the timings shifted.

(6). Another Example of Bolt and Nut (FIG. 19) FIG. 19 shows another form of the bolt and nut. In the example shown in (A), the thread portion of the bolt 1 is formed into a portion having only the coarse thread 5 and a portion having the coarse thread 5 and the fine thread 6 formed in combination. There is.

When this type of bolt 1 is manufactured by rolling, the flat die 14 is provided with only the coarse thread forming threads, the coarse thread forming projections 15 and the fine thread. It is sufficient to form a portion provided together with the forming ridge 16.

In the example shown in (B), the thickness of the lock nut 3 is larger than the thickness of the main nut 2. When the bolt 1 has a combination of the coarse thread 5 and the fine thread 6, the catching amount with the lock nut 3 is smaller than that in the case where only the fine thread 6 is formed. When it is desired to secure high fastening strength, it is preferable to use such a thick lock nut 3.

On the contrary, when it is desired to obtain a high fastening strength for the work 4, the thick main nut 2 can be used as shown in FIG.

(7). Others The present invention can be embodied in various ways other than the above embodiment. For example, the pitch of the threads to be manufactured is not limited to the device for forming the coarse threads and the fine threads on the bolt, and can be variously set as necessary.
It goes without saying that the present invention can be applied not only to the production of bolts of JIS standard or ISO standard, but also to the production of bolts of other standards or non-standard.

In the bolt, the pitch ratio of the two threads is not limited to an integral multiple, but may be set to a non-integral multiple such as 1.5 times or 2.3 times. . When the pitch ratio is set to a non-integer multiple, the group of thread grooves with a small pitch do not line up in the axial direction of the bolt but line up in a state of being displaced in the circumferential direction of the bolt, so the lock nut and bolt are caught. Will be equalized at each part along the circumferential direction, and as a result, the fastening strength can be improved.

The types of bolts that can be manufactured by the present invention are not limited to hexagonal bolts, but may be square headed bolts, hexagon socket headed bolts, pot headed head bolts (including screws), countersunk headed head bolts, double cut heads. It can be applied to manufacture various types of bolts such as bolts, eyebolts, and reamer bolts.

It is also possible to form the bolt in a state where three threads are crossed and fasten with three types of nuts (triple nuts) having different pitches of large, medium and small. When a plurality of threaded portions are formed on one bolt, such as a double-threaded bolt, at least one threaded portion is manufactured by the present invention, and other threaded portions are manufactured by a conventional method. It is also possible.

Further, as described in claim 4, the present invention can be applied to a bolt manufacturing apparatus using various molds (generally molds).

The bolts may have different helical pitches of threads having different pitches, such that the threads of the coarse thread are the right-hand threads and the threads of the fine thread are the left-hand threads. It can also be applied to the manufacture of such bolts.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a bolt manufactured by the present invention.

FIG. 2 is a view showing a usage state of the bolt of FIG.

3 is a diagram showing details of the bolt of FIG. 1. FIG.

FIG. 4 is a plan sectional view of the bolt of FIG.

5 is a diagram showing the shape of a screw thread in the bolt of FIG. 1. FIG.

FIG. 6 is a schematic front view of the first embodiment.

FIG. 7 is a schematic side view showing a usage state of the die according to the first embodiment.

8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a schematic plan view of a die.

[FIG. 10] (A) is a partial plan view of the die, (B) to (H) are (A)
It is each sectional view of.

FIG. 11 is a partial perspective view of a die.

FIG. 12 is a schematic side view of a die.

FIG. 13 is a cross-sectional view in a processed state.

FIG. 14 is a diagram showing a second embodiment.

FIG. 15 is a diagram showing a third embodiment.

FIG. 16 is a plan view of the fourth embodiment.

17 is a sectional view taken along the line XVII-XVII of FIG. 16.

FIG. 18 is a diagram showing a fifth embodiment.

FIG. 19 is another example diagram of a bolt and a nut.

[Simple explanation of symbols]

1 bolt (hexagon bolt) 2 main nut 3 lock nuts 5 coarse thread 6 fine threads 14 flat dice 15 Coarse thread forming ridges 16 Fine threads for forming threads 17 Coarse thread forming groove 19 round dice 22, 23 Chaser as an example of cutting blade

Claims (5)

[Claims] 1. An apparatus for producing a multi-screw bolt in which a plurality of threads having different pitches are formed to intersect each other by a rolling method using a die such as a flat die or a round die. The device for manufacturing a bolt, wherein the die is formed in a state in which a group of protrusions for forming the plurality of threads is crossed on the bolt. 2. A plurality of threads having different pitches in the bolt are coarse and fine threads defined in JIS or ISO standard, and the die has a projection for forming a parallel male thread. The bolt manufacturing apparatus according to claim 1, wherein the fine male thread forming projection is formed so as to intersect and extend. 3. An apparatus for producing a multi-screw type bolt in which a plurality of threads having different pitches are formed in a crossed state by a cutting method using a cutting tool such as a cutting tool or a chaser. , Rotation means for rotating the bolt material around its axis,
Manufacturing of bolts provided with a plurality of blades for individually processing a plurality of threads having different pitches, and a plurality of moving means for moving each blade parallel to the material of the bolt according to the pitch of the threads apparatus. 4. A state in which a plurality of threads with different pitches cross each other by a molding method such as a casting method using a metal material, a die casting method or a lost wax method, or an injection molding method using a synthetic resin material. An apparatus for manufacturing a multi-screw bolt formed on a bolt, wherein a molding die is formed with a group of protrusions for forming the plurality of threads on the bolt crossing each other. Manufacturing equipment. 5. The manufacturing apparatus according to any one of claims 1 to 4 is used to simultaneously form a plurality of threads having different pitches on the material of the bolt while crossing the threads. A method of manufacturing bolts.