JP2013024418A - Lock bolt and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an easy-to-manufacture lock bolt that fastens and fixes members or the like very firmly without loosening even if vibration is applied repeatedly.SOLUTION: The lock bolt includes a shaft section 1 having a screw formed on the outer circumference and a head section 2 provided at one end of the shaft section 1. The head section 2 is formed of a body part 201 having a hexagonal cross-sectional shape, a tubular skirt part 202 continued from the body part 201 and widened radially outward from the body part 201 with a concave surface using a suspended curved surface. The lower end surface 203 of the outer surface of the skirt part 202 is parallel to the axis X-X of the body part 201. The inner surface of the skirt section 202 is bored in an inverted-suspended curved surface shape while leaving a flat portion at a bottom rim 204.

Description

  The present invention relates to a locking bolt and a method of manufacturing the locking bolt, and more particularly, a locking bolt capable of firmly fixing and fixing a member or the like without being loosened even when repeated vibration is applied when the member or the like is clamped and fixed. Further, the present invention relates to a method that can efficiently manufacture such a locking bolt using a header without using a laborious method such as cutting.

Bolts and nuts are widely used for fastening and fixing members and the like.
However, there is a problem that bolts and nuts loosen when repeated vibrations act on the tightened and fixed portions.

For this reason, various devices have been conventionally made.
For example, a fastening member including a head portion and a taper portion, in which the inner surface of the taper portion is formed in a conical curved surface and the outer surface of the taper portion is formed in a concave curved surface has been proposed (patent) Reference 1).

  According to this fastening member, the object to be fastened can be firmly tightened and fixed, and a vibration and impact can be absorbed by the action of the taper portion to obtain a suitable anti-loosening action.

However, in the case of a special shape such as this fastening member, it is difficult to manufacture unless it is a cutting process using a lathe, etc. In addition, the cutting process requires a special skill for manufacturing, and thus is costly. There was a problem that it would be expensive.
In recent years, there has been a demand for bolts having a further anti-loosening action.

Patent No. 3860200

  The present invention has been made to solve the above-described conventional problems, and the object of the present invention is to be able to clamp and fix a member or the like very firmly without being loosened even when repeated vibrations are applied. An object of the present invention is to provide a locking bolt and a method for efficiently manufacturing such a locking bolt using a header without using a laborious method such as cutting.

That is, the present invention according to claim 1
A shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
The inner surface of the skirt portion has a structure that is hollowed out in a reverse suspended curved surface shape while leaving a flat portion at the periphery of the bottom portion, and further, the intersection of the inner surface of the skirt portion and the shaft portion is configured in an R shape. It is intended to provide a loosening bolt that is rounded.

The present invention according to claim 2 is a shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
The inner surface of the skirt portion has a structure in which a flat portion is left on the periphery of the bottom portion and is hollowed in a substantially reverse suspended curved surface shape as a whole and a polygonal body shape having six or more corners in the circumferential direction. Furthermore, the crossing point between the inner surface of the skirt portion and the shaft portion is formed in an R shape to provide a loosening bolt that is rounded.

According to the present invention, it is possible to obtain a locking bolt capable of tightening and fixing a member or the like very firmly without being loosened even when repeated vibrations are applied.
Further, according to the method of the present invention, it is possible to efficiently produce a locking bolt that can tighten and fix a member or the like extremely firmly without being loosened even when repeated vibrations are applied, using a header. .
Moreover, the method of the present invention is not based on cutting that requires a high level of skill, and is easy to manufacture.

It is a front view which shows one aspect | mode (Hereafter, it may be called "the slack stop bolt obtained by 1st of this invention.") Of the slack stop bolt obtained by this invention. It is sectional explanatory drawing which shows the one aspect | mode of the locking bolt obtained by this invention. It is explanatory drawing which shows a shape when it looks up from the SS line | wire of FIG. 1 about the one aspect | mode of the locking bolt obtained by this invention. It is explanatory drawing which shows the shape (reverse suspended curved surface shape) of the inner surface of the hollowed skirt part about the one aspect | mode of the locking bolt obtained by this invention. It is a front view which shows the other aspect (Hereafter, it may be called "the loosening bolt obtained by the 2nd of this invention.") Of the locking bolt obtained by this invention. It is sectional explanatory drawing which shows the other aspect of the locking bolt obtained by this invention. It is explanatory drawing which shows a shape when looking up from the TT line | wire of FIG. 5 about the other aspect of the locking bolt obtained by this invention. About the other aspect of the locking bolt obtained by the present invention, the shape of the inner surface of the hollowed skirt portion (as a whole, a reverse suspended curved surface shape and a polygonal shape having six or more corners in the circumferential direction) is shown. It is explanatory drawing. It is a front view which shows the one aspect | mode of the wire used for the method of this invention. It is explanatory drawing which shows an example of the cutting process in the method of this invention, and the header used for this. In the method of this invention, it is explanatory drawing which shows a pattern when the head forging process and the counterbore process are performed using the header. In the method of this invention, it is explanatory drawing which shows the pattern just before performing head forging process and counterbore process using a header. In the method of this invention, it is a schematic explanatory drawing when the upper metal mold | die at the time of performing a head forge process and a counterbore process is seen from the lower side. In the method of this invention, it is a schematic explanatory drawing when the lower metal mold | die at the time of performing a head forge process and a counterbore process is seen from the upper side. It is sectional explanatory drawing which shows an example of the counterbore die piece used in the 1st method of this invention. It is a top view which shows an example of the counterbore die piece used in the 1st method of this invention. It is a cross-sectional view of the vicinity of the center line of the flow path in FIG. It is sectional explanatory drawing which shows an example of the counterbore die piece used in the 2nd method of this invention. It is a top view which shows an example of the counterbore mold piece used in the 2nd method of this invention. It is explanatory drawing which shows the cross-sectional structure of the spiral triple structure pipe (spiral triple structure pipe) by twist process. It is explanatory drawing which shows an example of the state which has arrange | positioned the ultrasonic vibration generator to the upper and lower sides of a metal mold | die, and the outer periphery of the liquid delivery pipe which consists of a spiral multiplex structure pipe. It is explanatory drawing which shows the implementation condition of the slack test method.

The first of the present invention relates to a locking bolt,
A shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
The loosening prevention bolt which has the structure where the inner surface of the said skirt part was hollowed out in the shape of a reverse suspension curved surface, leaving a flat part at the periphery of a bottom part is provided.

The first aspect of the present invention will be described below in detail with reference to the drawings.
FIG. 1 is a front view showing one mode of a loosening bolt obtained by the present invention (that is, “a loosening bolt obtained by the first of the present invention”), and FIG. 2 is an explanatory sectional view thereof.
FIG. 3 is an explanatory diagram showing the shape of the locking bolt obtained according to the first aspect of the present invention when viewed from the line SS of FIG.
Moreover, FIG. 4 is explanatory drawing which shows the shape (reverse suspended curved surface shape) of the inner surface of the skirt part hollowed out about the locking bolt obtained by 1st of this invention.

  The locking bolt A obtained by the first aspect of the present invention comprises a shaft portion 1 having a screw on the outer periphery and a head portion 2 provided at one end of the shaft portion 1, and the head portion 2 has a hexagonal cross-sectional shape. And a cylinder formed in an expanded shape so as to extend away from the main body portion 201 in the radial direction and draw a concave surface using a suspended curved surface. The lower end surface 203 of the outer surface of the skirt portion 202 is parallel to the axis of the main body portion 201, and the inner surface of the skirt portion 202 leaves a flat portion on the bottom peripheral edge 204. However, it has a structure that is cut out into a reverse suspended curved surface.

[Structure of the locking bolt obtained by the first aspect of the present invention]
The loosening prevention bolt A obtained by the first aspect of the present invention includes a shaft portion 1 having a screw on the outer periphery and a head portion 2 provided at one end of the shaft portion 1. In that respect, it is the same as a normal bolt, but the structure of the head 2 is special in order to obtain a loosening prevention effect.
That is, the head 2 of the locking bolt A manufactured according to the present invention is connected to the main body 201 having a hexagonal cross-sectional shape and the main body 201, and moves away from the main body 201 outward in the radial direction. As described above, the cylindrical skirt portion 202 is formed in an expanded shape by drawing a concave surface using a suspended curved surface.

Here, the main body 201 has a hexagonal cross-sectional shape in the same manner as a normal bolt head.
On the other hand, the skirt portion 202 is formed in a cylindrical shape having a substantially skirt-like shape that is connected to the main body portion 201 and is formed to move away from the main body portion 201 radially outward.
In addition, the skirt portion 202 draws a concave surface using a suspended curved surface, and has an expanded shape (that is, as seen in FIG. 2 which is a cross-sectional explanatory diagram) Formed to be open).
More precisely, the skirt portion 202 (outer surface thereof) includes a suspended curved surface instead of the entire suspended curved surface (suspended surface; catenoid), and is formed in an expanded shape by drawing a concave surface using a part thereof. Yes. In terms of the cross section, it is formed in an expanded shape with a catenary curve (catenary curve; catenary curve).
In addition, the shape that can be formed when both ends of chains and ropes are fixedly suspended (held) is called a suspension curve (also called a suspension line or catenary curve), and this suspension curve (suspension line; catenary curve) ) Is called a suspended curved surface (also called a suspended surface or a catenoid).
As described above, the outer surface of the skirt portion 202 is formed in an expanded shape by drawing a concave surface using a suspended curved surface. By forming the outer surface of the skirt portion 202 in this way, elasticity is given to this portion, and when fixing the member or the like, it can be fixed with a sufficient tightening force, and after tightening, it is in a state in which there is no looseness. be able to.
In addition, the outer surface of the skirt portion 202 may be a spline curve shape as well as a suspended curved surface.

  However, the lower end surface 203 of the outer surface of the skirt portion 202 is parallel to the axis XX direction of the main body portion 201. As a result, even if this loosening prevention bolt is quenched using an iron-based material, no crack (crack) is generated at the tip of the expanded skirt portion 202.

The inner surface of the skirt portion 202 is hollowed out into a “reverse suspended curved surface shape” while leaving a flat portion (becomes a seating surface) on the bottom peripheral edge 204 by hollowing out so that the shape of the hollowed portion becomes a reverse suspended curved surface shape. It has a structure.
The reason why the "reverse" suspended curved surface is used here is that the hollowed-out structure has a shape opposite to the "suspended curved surface" (suspended surface; catenoid), and the reverse suspended curved surface " The reason for the “shape” is that, as is apparent from FIGS. 1 to 4, it is not the reverse suspended curved surface itself but a shape close to this.
In addition, the inner surface of the skirt portion 202 has a structure hollowed in a reverse suspended curved surface shape and a structure hollowed in a spline curve (spline curved surface) shape. You can also.
The diameter of the shaft portion 1 can be set to an appropriate size as required. For example, the size of a small one is from 3 mm and the size of a large one is 36 mm, but is not limited thereto.

  The locking bolt A obtained by the first aspect of the present invention has a structure in which the inner surface of the skirt portion 202 is hollowed out in a reverse suspended curved surface, and in addition, the base portion of the shaft of the skirt portion 202, that is, The intersection (groove portion) 205 between the inner surface of the skirt portion 202 and the shaft portion 1 should be somewhat rounded rather than not rounded (pointed) as much as possible. That is, it is preferable that the leading edge that is the intersection of the inner surface of the skirt portion 202 and the shaft portion 1 has a rounded R shape (R shape). The radius (R) of the portion is more than 1 mm, and just about 1.5 mm or less is just right. Here, when the base of the shaft of the skirt portion 202, that is, the intersection (groove portion) 205 between the inner surface of the skirt portion 202 and the shaft portion 1 is sharp and has a wedge shape at the leading edge, the absorption of elasticity is large. Since the compressive stress is concentrated at the cutting edge, and then concentrated on the inner circle edge of the seating surface, it cannot withstand such a state and cannot be completely fixed on the seating surface even when torque is applied. , It will relax over time.

Next, the second of the present invention will be described in detail with reference to the drawings.
FIG. 5 is a front view showing another embodiment of the locking bolt obtained by the present invention (that is, “the locking bolt obtained by the second of the present invention”).
FIG. 6 is a cross-sectional explanatory view showing a locking bolt obtained by the second of the present invention.
FIG. 7 is an explanatory view showing the shape of the locking bolt obtained by the second of the present invention when looking up from the TT line of FIG. 5.
FIG. 8 shows the shape of the inner surface of the hollowed skirt portion (a generally reverse suspended curved surface as a whole, and a polyhedron having six or more corners in the circumferential direction, for the locking bolt obtained by the second of the present invention. It is explanatory drawing which shows a shape.

  The locking bolt B obtained by the second of the present invention comprises a shaft portion 1 having a screw on the outer periphery and a head portion 2 provided at one end of the shaft portion 1, and the head portion 2 has a hexagonal cross-sectional shape. And a cylinder formed in an expanded shape so as to extend away from the main body portion 201 in the radial direction and draw a concave surface using a suspended curved surface. The lower end surface 203 of the outer surface of the skirt portion 202 is parallel to the axis of the main body portion 201, and the inner surface of the skirt portion 202 leaves a flat portion on the bottom peripheral edge 204. On the other hand, it has a structure which is hollowed out in a substantially reverse suspended curved surface as a whole and in a polygonal shape having six or more corners in the circumferential direction.

The locking bolt B obtained by the second of the present invention is the same as the locking bolt A obtained by the first of the present invention described above, except that the shape of the inner surface of the skirt portion 202 is different. is there.
That is, the locking bolt A obtained by the first aspect of the present invention has a structure in which the inner surface of the skirt portion 202 is hollowed out in a reverse suspended curved surface shape while leaving a flat portion on the bottom edge 204. The loosening prevention bolt B obtained by the second aspect of the present invention is such that the inner surface of the skirt portion 202 has a generally reverse suspended curved surface shape as a whole while leaving a flat portion on the bottom peripheral edge 204 and has six or more corners in the circumferential direction. It has a structure that is cut out in a polygonal shape with a corner (like a strip-shaped aggregate).
Here, the “substantially reverse suspended curved surface shape as a whole” means that in the locking bolt B obtained by the second aspect of the present invention, the inner surface of the skirt portion 202 appears to be “substantially a reverse suspended curved surface shape as a whole” To be precise, it is a reverse suspended curved surface shape when viewed from the axis XX direction, but is not necessarily a curved surface shape when viewed from the circumferential direction. As shown in FIG. This is because it has a structure that is cut out into a polygonal shape with 20 corners and 16 corners in FIG. Here, the “circumferential direction” indicates not the axial direction but the direction perpendicular to the axial line.

In the same manner as described for the loosening bolt A obtained by the first aspect of the present invention, the outer surface of the skirt portion 202 uses a suspended curved surface for the loosening bolt B obtained by the second aspect of the present invention. In addition, it can also be made into a spline curve shape.
Similarly to the loosening bolt A obtained by the first aspect of the present invention, the loosening bolt B obtained by the second aspect of the present invention also has a generally spline curve as the inner surface of the skirt portion 202 as a whole. And it can also have a structure hollowed out in the shape of a polyhedron with six or more corners in the circumferential direction.

  Also in the locking bolt B obtained by the second aspect of the present invention, the base portion of the shaft of the skirt portion 202, that is, the intersection (groove portion) 205 between the inner surface of the skirt portion 202 and the shaft portion 1 is unexpectedly rounded as much as possible. It is better to have some roundness than not to have it (pointed). That is, it is preferable that the leading edge that is the intersection of the inner surface of the skirt portion 202 and the shaft portion 1 has a rounded R shape (R shape). The radius (R) of the part is just about 1 mm or more and 2 mm or less (1R to 2R).

It is the first method of the present invention and the second method of the present invention that provides a method of manufacturing the first and second locking bolts of the present invention having such a structure using a header. It is a method.
In addition, it is also possible to manufacture by cold forging or hot forging by changing the shape of the counterbore die piece instead of manufacturing using the header.

Hereinafter, a method for manufacturing the first locking bolt according to the present invention (the first method according to the present invention) and a method for manufacturing the second locking bolt according to the present invention (the second method according to the present invention) will be described. This will be described with reference to the drawings.
Here, the first method of the present invention and the second method of the present invention are different in the shape of the counterbore mold piece to be used. As a result, the inner surface of the skirt portion of the obtained locking bolt is hollowed out. Since the steps are basically performed in the same manner except that the shapes are different, common portions will be described below collectively.

That is, the first method of the present invention relates to a method of manufacturing a locking bolt,
A shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
The inner surface of the skirt portion is a method of manufacturing a locking bolt having a structure in which a flat portion is left on the periphery of the bottom portion and is hollowed out in a reverse suspended curved surface shape,
An upper mold having a cutting knife and having a punch, and a lower mold in which a counterbore mold piece for performing a counterboring process for punching the inner surface of the skirt portion into a reverse suspended curved surface is fitted and detachably fitted, Using a header with
A wire that can be forged is cut into a predetermined length with a cutting knife, and then the head is forged and counterbored with the upper die and the lower die on the cut wire, and one end of the wire And forming a head portion composed of a main body portion and a skirt portion, the skirt portion being connected to the main body portion, and extending away from the main body portion in the radial direction, and a suspended curved surface It is formed in an expanded shape by drawing a concave surface using, and the inner surface of the skirt portion has a structure that is hollowed out in a reverse suspended curved surface shape while leaving a flat portion at the periphery of the bottom portion,
Next, using a trimming automatic machine, the cross-sectional shape of the main body portion of the head is a hexagon,
Next, by rolling, by forming a screw on the outer circumference of the wire rod excluding the head, it becomes a shaft part,
Next, the surplus wall is cut so that the lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion.
It is characterized by this.

In addition, the second method of the present invention relates to a method of manufacturing a locking bolt,
A shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
An anti-slack structure having a structure in which the inner surface of the skirt portion is hollowed out into a generally inverted suspended curved surface as a whole and having a polygonal body shape with six or more corners in the circumferential direction while leaving a flat portion at the periphery of the bottom portion. A method of manufacturing a bolt, comprising:
A counterbore which is provided with a cutting knife and has a punch, and the inner surface of the skirt is formed into a substantially reverse suspended curved surface as a whole and into a polygonal body having six or more corners in the circumferential direction. Using a header having a counterbore mold piece and a lower mold fitted in a removable manner,
A wire that can be forged is cut into a predetermined length with a cutting knife, and then the head is forged and counterbored with the upper die and the lower die on the cut wire, and one end of the wire And forming a head portion composed of a main body portion and a skirt portion, the skirt portion being connected to the main body portion, and extending away from the main body portion in the radial direction, and a suspended curved surface The inner surface of the skirt portion is formed in a widened shape while leaving a flat portion at the bottom periphery, and has a generally reverse suspended curved surface as a whole, and has six or more corners in the circumferential direction. It has a structure that is cut out into a polygonal shape,
Next, using a trimming automatic machine, the cross-sectional shape of the main body portion of the head is a hexagon,
Next, by rolling, by forming a screw on the outer circumference of the wire rod excluding the head, it becomes a shaft part,
Next, the surplus wall is cut so that the lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion.
It is characterized by this.

In the method of the present invention (the first method and the second method), an upper die having a cutting knife and having a pressing punch, and a counterbore die for performing a counterboring process by hollowing out the inner surface of the skirt portion The head is forged and counterbored using a header having a lower die fitted with a top and detachably fitted.
Here, the header (also referred to as a cold header) refers to a machine that makes a screw head by cold working. There are headers ranging from one (single header) to multi-stage, depending on the number of stages to be processed. Usually, a two-stage type or a three-stage type is used.
In addition, about this header, it shall mention suitably also in the description location about the process of a manufacturing method.

In the method of the present invention (the first method and the second method), a “wire material” that can be forged, in other words, a solid round bar material made of a metal material, preferably a steel material having a circular cross section is used. FIG. 9 is a front view showing an aspect of such a wire S. FIG. A raw material can be used for the wire.
In addition to steel, alloys with metals such as nickel, chromium, molybdenum, cobalt, and tungsten, such as stainless steel, nickel chromium steel, and chromium molybdenum steel, can be used as the steel material. In addition, a nonferrous metal material can also be used according to a use.
Hereinafter, the method of the present invention (first method and second method) will be described in the order of steps.

[Cutting process]
The first step is a cutting step.
The cutting step is a step of cutting a long wire into a predetermined length with a cutting knife called a shear knife.
The header is usually provided with such a cutting knife, but this can also be used in the present invention. In the header, this cutting process and the following head forging and counterboring are performed.

FIG. 10 shows an example of this cutting step and a header used therefor.
The header includes a horizontal type and a vertical type, but any of them can be applied. In the figure, a vertical type is shown.
In the figure, reference numeral 3 is a cutting knife, reference numeral 4 is a quill, and reference numeral 5 is a stopper. Here, the quill is a cylindrical feed base that moves in the axial direction while supporting the wire.
In this cutting process, specifically, for example, the wire S supported by the quill 4 is fed into the header H by a feed roller (not shown). When the long wire S is sent to the stopper 5, it is cut (sheared) to a predetermined length by the cutting knife 3.
The header H used in the method of the present invention (the first method and the second method) includes such a cutting knife 3 and cuts out the inner surface of the skirt portion and the upper die having a pressing punch. And a lower mold in which a counterbore mold piece for counterboring is fitted and detachably fitted.
The next head forging and counterboring are performed by the upper mold and the lower mold mounted on the header H.

[Process for head forging and counterboring]
The next step is a step of performing head forging and counterboring.
That is, the wire S cut in the cutting process as described above is conveyed to the center of the header H, and the head forging process is performed on the wire S cut here by the upper die and the lower die. And a counterbore process to form a head composed of a main body portion and a skirt portion at one end of the wire, and the skirt portion is connected to the main body portion and radially outward from the main body portion. The inner surface of the skirt part is hollowed out by a counterbore mold piece while leaving a flat part at the periphery of the bottom part. It shall have a structure.

Here, in the first method of the present invention, it is assumed that it has a structure that is hollowed out in a reverse suspended curved shape by a counterbore mold piece, whereas in the second method of the present invention, by a counterbore mold piece, As a whole, it has a substantially reverse suspended curved surface shape and a structure that is hollowed out into a polygonal body shape having six or more corners in the circumferential direction.
The shape of the counterbore mold piece in the first method of the present invention and the second method of the present invention will be described later.

FIG. 11 is an explanatory diagram showing a pattern when head forging and counterboring are performed using the header H. FIG.
FIG. 12 is an explanatory diagram showing a pattern immediately before the head forging process and the counterboring process are performed using the header H. At this time, head forging and counterboring are performed while applying ultrasonic vibration to the wire and / or mold.
FIG. 13 is a schematic explanatory diagram when the upper mold at this time is viewed from the lower side (when viewed from the position of the ZZ line in FIG. 12), and FIG. 14 is the lower mold at this time. It is a schematic explanatory drawing when a type | mold is seen from the upper side (when it looks down from the ZZ line position position of FIG. 12).

  The upper die will be described. In FIGS. 11 and 12, reference numeral 6 denotes a pressing punch. Reference numeral 7 denotes an upper punch guide for pressing, reference numeral 8 denotes an intermediate punch guide for pressing, and reference numeral 9 denotes a lower punch guide for pressing. The lower punch guide 9 for pressing is made of super hard metal. These are adapted to move on the ram side (upper side in the figure). Depending on the molding state, the pressing punch can be a multistage pressing method.

Next, the lower mold will be described. First, reference numeral 10 denotes a counterbore mold piece. Reference numeral 11 is a lower punch guide, reference numeral 12 is a frame guide, reference numeral 13 is a frame receiving guide, and reference numeral 14 is an inner guide. Reference numeral 15 denotes a fluid flow path that serves as a flow path for a demolding agent and a cooling liquid during molding. Reference numeral 16 denotes a gap provided between the upper mold and the lower mold.
Further, reference numeral 17 denotes an extrusion pin for extruding the molded product after completion of the head forging process and counterboring process, and reference numeral 18 denotes an extrusion pin guide.
In addition, the code | symbol P is a parting line (a type | mold matching surface, a dividing line of a metal mold | die).
The part of the mold surface that is worn by sliding is subjected to a wear-resistant surface treatment in advance as necessary. In addition, there is a part using a super hard material (super hard metal) partially.

  In the first method of the present invention, in the step of performing the head forging process and the counterboring process, the upper mold having the pressing punch 6 and the counterbored metal for performing the counterboring process of hollowing out the inner surface of the skirt portion into a reverse suspended curved surface shape. The head forging process and the counterbore process are performed using a header including a lower mold in which the mold piece 10 is detachably fitted. By performing this step, the outer shape of the locking bolt is generally solidified.

In the first method of the present invention, the counterbore mold piece 10 has a substantially disk shape as a whole as shown in FIGS. 15 and 16, but has a hollow structure having a cavity 101 at the center. Moreover, a stepped shoulder portion 102 that is one step higher is formed around the cavity 101.
The counterbore shoulder 102 has a reverse suspended curved surface.
That is, the counterbore mold piece 10 has a counterbore shoulder shape portion 102 that performs counterbore processing at the upper and lower ends around the cavity 101 in the center portion, and has one counterbore shoulder shape. When the part 102 is worn out or chipped, it is reversed and used. If the other counterbore shoulder 102 is chipped or worn after being used after being inverted, it is replaced with a new one.
Here, the counterbore process refers to a process of hollowing out the inner surface of the skirt portion 202 (in the first embodiment of the present invention, a process of hollowing into a reverse suspended curved surface), and the counterbore mold piece 10 (particularly, the counterbore shoulder portion 102) is used. Done.
The surface of the counterbore mold piece 10 is a surface different from a normal sliding surface in order to prevent cracks, cracks, etc., as well as to have been subjected to wear-resistant surface treatment in advance. In addition to being treated, it is made of a different material and heat treated.
The counterbore mold piece 10 is not only intended to have its life as long as possible, but it is possible to perform the counterbore processing without damage to the surface (without cracks, cracks, etc.). It is made of a tough material that does not easily generate cracks, cracks, etc., rather than an ultra-hard material that does not easily wear. In addition, a material that does not easily propagate cracks is used. Instead, when the counterbore mold piece 10 is worn, it can be reversed and used so that it can be exchanged.
FIG. 16 is a plan view showing an example of the counterbore mold piece 10. FIG. 17 is a cross-sectional view of the vicinity of the center line of the flow path in FIG. As shown in FIG. 17, the flow path 15 is provided with slits 15C at several places (two places in the figure). Thereby, a cooling fluid and a mold release agent (release agent) can be poured well into the cavity.

  In the second method of the present invention, as shown in FIGS. 18 and 19, the counterbore mold piece 10 has a hollow structure having a substantially disc shape as a whole but having a cavity 101 at the center. Moreover, a stepped shoulder portion 102 that is one step higher is formed around the cavity 101. The counterbore shoulder portion 102 has a reverse suspended curved surface as a whole, and has a polygonal shape (strip-shaped aggregate) having six or more corners (16 corners in FIGS. 18 and 19) in the circumferential direction. The inner surface of the skirt portion has a substantially reverse suspended curved surface shape as a whole and a structure that can be cut into a polygonal body shape having six or more corners in the circumferential direction. ing.

In addition, when tens of thousands are molded using a mold, it is inevitable that wear occurs. Therefore, in the present invention, the counterbore mold piece 10 is inverted and used so that it can be quickly replaced with a new one when worn (for example, when wear of about 0.1 mm or the like occurs). It is.
In addition, when the backlash is caused by wear or the like when reversed, the occurrence of backlash can be suppressed by coating the surface of the worn portion by the amount of wear. Here, any coating material can be used as long as it can be coated thickly, such as zinc.

In the present invention, the counterbore mold piece 10 is fitted to the lower mold, more specifically, to the piece receiving guide 13 so as to be detachable. That is, the frame receiving guide 13 is for fitting and supporting the counterbore mold piece 10.
The piece receiving guide 13 is not particularly limited in shape as long as it can fit and support the counterbore die piece 10. As shown in FIGS. 11 and 12, the frame receiving guides 13 positioned on the left and right have notches corresponding to the counterbore shoulders 102 formed on the counterbore mold top 10, respectively.

By operating the pressing punch 6 in a state where the counterbore shoulder piece 102 of the counterbore mold piece 10 is fitted to the frame receiving guide 13 (lower mold) so as to contact the inner surface of the skirt portion 202, A counterbore process is performed together with the head forging process, and the inner surface of the skirt part 202 is formed in a reverse suspended curved surface shape (first method of the present invention) while leaving the flat part 204 at the periphery of the bottom part, or as a whole, a reverse suspended curved surface. In addition, each of them is cut into a polygonal body having six or more corners (16 corners in FIGS. 18 and 19) in the circumferential direction (second method of the present invention).
At the same time, a hexagonal cross-sectional shape that has not yet been formed into a hexagonal cross-sectional shape at this time, but a hexagonal cross-sectional shape in the next process, is connected to the main body portion 201 and is radially outward from the main body portion 201. A head 2 is formed which includes a cylindrical skirt portion 202 that is formed in an expanded shape so as to be far away and to draw a concave surface using a suspended curved surface.
The concave surface using the suspended curved surface formed on the outer surface of the cylindrical skirt portion 202 has a shape of the lower inner side of the pressing lower punch guide 9 (a concave surface using the suspended curved surface and Transcribed).

  When performing head forging and counterbore processing, an air gap 16 is formed between the upper die and the lower die, and serves as a clearance area for the wire under the skirt portion during head forging and counterbore processing. In this state, the head forging process and the counterboring process may be performed. The presence of such voids 16 is effective for preventing damage to the mold. When the gap 16 does not exist as in the prior art, there is no escape space for the excess amount of wire (the remainder of the molding), so there was no mold, but by having the gap 16, the life of the mold Can be extended significantly to 5000 to 10,000 shots.

When one of the counterbore shoulders 102 of the counterbore mold piece 10 is worn, it is reversed and the other non-wearing counterbore shoulder 102 is turned up so that the frame receiving guide 13 (lower) The head forging and counterboring can be performed. When both of the counterbore shoulders 102 are worn, they are replaced with new counterbore mold pieces 10.
When the counterbore shoulder 102 is worn in this manner, the counterbore mold piece 10 can be reversed or only the counterbore mold piece 10 can be replaced while the piece receiving guide 13 remains unchanged. be able to.

  When performing the head forging process and the counterboring process, ultrasonic vibration can be applied while flowing the coolant through the flow path 15. Further, when demolding, ultrasonic vibration can be applied while flowing a demolding agent (release agent) through the flow path 15. As the coolant and demolding agent (release agent), those usually used can be used. The supply of the fluid to the flow path 15 can usually be performed in any process before and after installing the wire material which is a molding material.

  While applying ultrasonic vibration to the wire rod and / or the mold through the liquid flow pipe 151, which will be described later, or the upper and lower sides of the mold, as will be described later, Forging and counterboring can be performed.

Here, one end of the flow path 15 opens as an opening 15A on the cavity surface, and the other end 15B opens to the outside.
By opening one end 15A of the flow path 15 as an opening 15A on the cavity surface, the mold can be cooled and lubricated.
The other end 15B of the flow path 15 is open to the outside, and a liquid delivery pipe 151 is connected to the other end 15B.
As such a liquid delivery pipe 151, it is preferable to use a spiral multi-structure pipe.

This spiral multi-structure pipe (spiral multi-structure pipe) is, for example, a smooth metal circular pipe made of steel pipe, stainless steel pipe (heat resistant SUS, etc.), titanium pipe, etc. It is the metal pipe | tube (metal tube) shape | molded in this. By applying twist processing to triple and quadruple, a multi-structure spiral pipe is obtained.
FIG. 20 is an explanatory view showing a cross-sectional shape of an example of this spiral multiple structure pipe (spiral multiple structure pipe). That is, FIG. 20 shows an explanatory view showing a cross-sectional structure of a spiral triple structure pipe (spiral triple structure pipe) by the twist processing.

By using such a spiral multi-structure pipe, particularly a spiral triple structure pipe, the flow rate can be increased by about three times if the pipe has the same diameter, so that a pipe having a smaller diameter can be used. It is easy to handle the piping inside. In addition, since the cooling and lubricating oil to be fed into the mold cavity through the flow path 15 uses a plurality of liquids, a liquid delivery pipe suitable for these is used to feed into the pipe. When such a spiral triple structure pipe is used, the liquid moves in the spiral triple structure pipe while rotating spirally (spiral), and naturally plays the role of mixing and stirring. Thus, it has been found that there is an advantage that mixing and stirring of these plural liquids is not required.
In addition, the diameter of a spiral triple structure pipe is 6-8 mm normally, and what made this about 8-10 turns is used.

In the present invention, the ultrasonic vibration generator 152 can be disposed on the outer periphery of the liquid delivery pipe 151 formed of the spiral multi-structure pipe as described above. FIG. 21 shows an example of a state in which the ultrasonic vibration generator 152 is arranged on the outer periphery of the liquid delivery pipe 151 made of a spiral multi-structure pipe. In the figure, reference numeral 153 denotes a liquid tank (in the figure, three tanks A tank, B tank, and C tank), and reference numeral 154 denotes a liquid pump.
Further, as shown in FIG. 21, ultrasonic vibration generators 152 can be arranged on the upper and lower sides and the right and left sides of the mold D. It should be noted that the ultrasonic vibration generators 152 can be arranged only on the upper and lower sides of the mold D or only on the left and right sides of the mold D as necessary. The ultrasonic vibration generators 152 are preferably arranged at about three to six locations at positions that are as uniform as possible.
In this manner, the ultrasonic vibration generators 152 can be arranged on the outer periphery of the liquid delivery pipe 151 made of a spiral multi-structure pipe and on the upper, lower, left, and right sides of the mold D.
The basic configuration of the ultrasonic vibration generator 152 includes an ultrasonic transmitter that generates ultrasonic power and an ultrasonic vibrator that converts the electric vibration into mechanical vibration (for example, a ceramic-type pressure vibrator). ) And known ones can be used.
The ultrasonic vibration can be adjusted so as to be generated continuously or intermittently according to the manufacturing speed or the like. Further, the oscillation strength can be controlled in accordance with the manufacturing speed and the like.

  In the present invention, the ultrasonic vibration generating device 152 is arranged on the outer periphery of the liquid delivery pipe 151 composed of the spiral multi-structure pipe in this way, and ultrasonic vibration is given to the liquid passing through the pipe. A device for generating ultrasonic vibration is attached to a liquid tank containing liquid, and ultrasonic vibration is applied to the liquid in the tank and the liquid is not pumped. For this reason, the liquid tank becomes unnecessary.

The ultrasonic wave used in the present invention has a frequency between the ultrasonic vibration generator provided on the outer periphery of the liquid delivery pipe 151 formed of a spiral multi-structure pipe and the ultrasonic vibration generator provided on the upper and lower sides and the left and right sides of the mold D. Although they are different, they can be used as needed.
The ultrasonic waves used in the ultrasonic vibration generators provided on the upper, lower, left and right sides of the mold D are generally 10 to 50 kHz, preferably 15 to 50 kHz. It adjusts and uses as needed in the range of 15-50 kHz.
On the other hand, the ultrasonic wave used in the ultrasonic vibration generator provided on the outer periphery of the liquid delivery pipe 151 composed of a spiral multi-structure pipe may be lower than this and is generally 5 to 15 kHz. It adjusts and uses as needed in the range of 5-15 kHz.
Using such ultrasonic waves in the range of 5 to 15 kHz, an ultrasonic vibration generator 152 is disposed on the outer periphery of the liquid delivery pipe 151 formed of a spiral multi-structure pipe, and ultrasonic waves are applied to the liquid passing through the pipe through the pipe. When vibration is applied, the ultrasonic vibration propagates well in a liquid or solid, so that the ultrasonic vibration is applied to the liquid (coolant, demolding agent, etc.) in the flow path 15 connected to the liquid delivery pipe 151. It will be.
Furthermore, ultrasonic vibration generators 152 are arranged on the upper, lower, left, and right sides of the mold D to apply ultrasonic vibrations in the range of 15 to 50 kHz as described above.
Then, ultrasonic vibration is also applied to the wire and / or mold, and head forging and counterboring can be performed while applying ultrasonic vibration to the wire and / or mold. As a result, friction can be reduced, wear can be prevented, seizure between the mold and the work (wire) can be prevented, and demolding (releasing) can be facilitated. Moreover, the usage-amount of a mold release agent (release agent) can be suppressed. As a result, moldability (forgeability) can be improved and the mold life can be extended.
Thus, in the present invention, the head forging process and the counterboring process can be performed while applying ultrasonic vibration to the wire and / or the mold.
The control of the ultrasonic vibration device is as follows.
(1) The control method of the ultrasonic vibration generators arranged on the upper, lower, left and right sides of the mold D can be either manual or automatic, and operated either manually or automatically according to the molding cycle of the material. To be able to.
(2) The ultrasonic vibration device disposed on the outer periphery of the liquid delivery pipe and the ultrasonic vibration generation devices disposed on the upper, lower, left and right sides of the mold D are basically used and interlocked together. Individual operations can be performed as necessary.

  Using such ultrasonic waves, head forging and counterboring are performed while applying ultrasonic vibration to the wire and / or mold, and further, demolding while applying ultrasonic vibration to the wire and / or mold. As a result, friction can be reduced, wear can be prevented, and demolding can be facilitated.

  The steps described above are performed while exchanging punches and guides, and can be performed using a multistage press or the like.

  After the process of performing the head forging process and the counterbore process as described above is completed, the molded product is extruded by the extrusion pin 17 and is sent to the process of performing the next head hexagonal cutting process.

In the above process, the supply control of the liquid to the flow path is as follows.
(1) When the molding material or the semi-molded product is set at a predetermined position of the mold, the liquid is automatically supplied through the flow path into the cavity.
(2) Next, when the liquid is accumulated in about 85% of the inside of the cavity (space) (instantaneous), the pumping of the liquid is stopped by automatic control and the molding starts.
(3) The liquid in the cavity is discharged from the flow path at this time, passes through the liquid delivery pipe 151 outside the mold, and enters the return liquid tank 153.
(4) The liquid cooled in the return liquid tank 153 is again supplied from the return liquid tank 153 into the cavity through the liquid delivery pipe 151 (such as a spiral multi-structure pipe) by automatic control.
(5) When the amount of liquid is reduced, a new liquid is additionally replenished and controlled by a series of automatic controls.

[Process of performing head hexagon cutting]
The next step is a step of performing head hexagonal cutting.
This step is a step of making the cross-sectional shape of the main body portion of the head portion a hexagon, and is performed using a trimming automatic machine (also called a trimer automatic machine) (not shown).
If necessary, a square or oval shape (polygon processing) can be used.
As this trimming automatic machine, those usually used can be used.
If this process is performed, the cross-sectional shape of the main-body part among the heads of a locking bolt will be a hexagon, and the external shape of a locking bolt will be hardened substantially.
In addition, a hexagonal hole is opened in the head of a round head bolt called a cap screw by replacing the jig as needed, instead of a normal hexagon bolt that has a hexagonal cross-sectional shape in this way. A hexagon socket head cap screw may be used.

[Process for rolling and finishing]
The next step is a step of performing rolling and finishing.
A thread (thread) is formed on the outer periphery of the shaft portion 1 by rolling.
Further, the surplus is cut so that the lower end surface 203 of the outer surface of the skirt portion 202 is parallel to the axis of the main body portion 201 by processing finishing.
As a result, the intended locking bolt as shown in FIGS. 1 and 2 can be manufactured.
In performing this rolling process, pointing (pre-processing) is performed in advance.
If necessary, it is also possible to form the screw by cutting and grinding instead of rolling.

Either rolling or finishing may be performed first.
The rolling process is performed using a rolling machine or the like.
Further, the work finish is performed by cutting and / or grinding.

[Heat treatment process (tempering process)]
Furthermore, a heat treatment process (tempering process) by quenching and tempering is performed on bolts that require strength. The heat treatment may be performed according to a required strength level according to a conventional method.

[Surface treatment process]
Furthermore, a surface treatment process (surface treatment processing) such as plating is performed as necessary.
Thereafter, a final inspection is performed to obtain a product. In the final inspection process, it is inspected whether the product shape is within the specifications, whether there are cracks or the like.

As described above, in the method of the present invention (the first method of the present invention and the second method of the present invention), the locking bolt can be manufactured basically using the header, and a high level of skill is achieved. Does not require the required cutting process.
Therefore, according to the method of the present invention (the first method of the present invention and the second method of the present invention), the member or the like can be clamped and fixed extremely firmly without being loosened even when repeated vibrations act. It is possible to efficiently manufacture a bolt that can be loosened.

  The locking bolts obtained by the method of the present invention (the first method of the present invention and the second method of the present invention) and the present invention (the first and second methods of the present invention) In the slack test by random extraction using the slack tester, all of the predetermined 17 minutes are cleared.

  The produced locking bolts obtained by the method of the present invention (the first method of the present invention and the second method of the present invention) and by the present invention (the first and second methods of the present invention) In the slack test, the first reason why the predetermined 17 minutes can be cleared and maintained at all times is that the outer surface of the skirt part is formed in an expanded shape with a concave surface using a suspended curved surface. The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and the inner surface of the skirt portion is formed in a reverse suspended curved surface shape (first aspect of the present invention) while leaving a flat portion at the periphery of the bottom portion. This is because each has a structure that is hollowed out in a substantially reverse suspended curved surface shape and a polygonal body shape having six or more corners in the circumferential direction (second aspect of the present invention).

Also, the bolts manufactured according to the present invention (the first method of the present invention and the second method of the present invention) and the bolts manufactured according to the present invention (the first and second aspects of the present invention). However, in the slack test, the second reason why the predetermined 17 minutes can be cleared and maintained at all times is the base of the shaft of the skirt portion 202, that is, the intersection (groove portion) of the inner surface of the skirt portion 202 and the shaft portion 1. ) 205 is formed in an R shape (R shape) and is rounded. Thus, if the intersection (groove part) 205 between the inner surface of the skirt part 202 and the shaft part 1 is configured in an R shape (R shape) and is rounded, the stress is applied uniformly, resulting in excessive torque. Since it is not applied, it can be fixed easily, and since the ground pressure increases, it does not loosen.
Here, the base of the shaft of the skirt portion 202, that is, the intersection (groove portion) 205 between the inner surface of the skirt portion 202 and the shaft portion 1 is not rounded, but has a cornered shape (wedge shape) where a straight line and a straight line intersect. ), Since the cutting edge is wedge-shaped, the stress is concentrated on the cutting edge (wedge), and the contact pressure is small, so it is easy to loosen. You cannot clear 17 minutes.

The loosening bolts thus obtained were subjected to a loosening test using a high-speed screw loosening tester (a looseness test using a NAS 3550 standard testing machine) according to the method shown in FIG. The results are shown in Table 1. In this test, since it did not loosen for 17 minutes, it was maintained and cleared as a locking bolt / nut.
In FIG. 22, reference numeral 30 is a test bolt, reference numeral 31 is a test nut, reference numeral 32 is a washer (washer), reference numeral 33 is a vibration barrel, reference numeral 34 is a vibration table, reference numeral 35 is an excitation stroke, and reference numeral 36 is an impact. Each stroke is shown.

[Looseness test method]
Test bolt (the first locking bolt of the present invention having the shape shown in FIGS. 1 and 2 manufactured by the first method of the present invention as shown in the figure, and the first locking bolt of the present invention as shown in the figure) 5 and 6 of the present invention manufactured by the method 2 in FIG. 5 and 6 (M16 × 80-4.8) together with nuts (test nuts) each having a size corresponding to this. It was attached to a testing machine and tested under the following conditions. When it did not relax for 17 minutes, the return torque was measured.

・ Testing machine: High-speed screw slack testing machine ・ Vibration condition: Frequency: 1780 rpm
Shaking table stroke: 11 mm
Impact stroke: 19mm
Vibration direction: Bolt axis perpendicular direction

-Judgment of looseness: When the alignment mark of the test bolt, test nut and washer (washer) was shifted and the washer was able to be turned by hand, it was judged as "loose".

  According to the results of Table 1, both the first locking bolt of the present invention and the second locking bolt of the present invention manufactured by the method of the present invention both loosen during the 17-minute test. You can see that there was no.

  The loosening bolt thus obtained can be effectively used for fastening and fixing various members.

DESCRIPTION OF SYMBOLS 1: Shaft part 2: Head part 2A: Upright part of wire rod 201: Main body part 202: Skirt part 203: Lower end surface of outer surface of skirt part 202 204: Bottom peripheral edge of inner surface of skirt part 202 205: Of skirt part 202 The base of the shaft (intersection of the inner surface of the skirt 202 and the shaft)
3: Knife 4: Quill 5: Stopper 6: Punch for pressing 7: Upper punch guide for pressing 8: Middle punch guide for pressing 9: Lower punch guide for pressing 10: Counterbore mold piece 101: Cavity 102: Counterbore shoulder 11: Lower punch guide 12: Frame guide 13: Frame receiving guide 14: Inner type guide 15: Fluid flow path 15A: Opening 15B: Other end of flow path 15C: Slit 151: Liquid delivery pipe 152: Ultrasonic vibration Generator 153: Liquid tank 154: Liquid pumping pump 16: Air gap 17: Extrusion pin 18: Extrusion pin guide 30: Test bolt 31: Test nut 32: Washer 33: Vibrating barrel 34: Excitation table 35: Excitation Stroke 36: Impact stroke A: Loosening bolt obtained by the first aspect of the present invention B: Obtained by the second aspect of the present invention Locking bolt P: parting line S: wire D: die entire H: Header

Claims (2)

A shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
The inner surface of the skirt portion has a structure that is hollowed out in a reverse suspended curved surface shape while leaving a flat portion at the periphery of the bottom portion, and further, the intersection of the inner surface of the skirt portion and the shaft portion is configured in an R shape. An anti-loosening bolt made round.
A shaft portion having a screw on the outer periphery;
A head portion provided at one end of the shaft portion,
The head is a main body having a hexagonal cross-sectional shape, and
A cylindrical skirt portion that is connected to the main body portion and is formed to expand away from the main body portion so as to move outward in the radial direction from the main body portion and to form a concave surface using a suspended curved surface. And
The lower end surface of the outer surface of the skirt portion is parallel to the axis of the main body portion, and
The inner surface of the skirt portion has a structure in which a flat portion is left on the periphery of the bottom portion and is hollowed in a substantially reverse suspended curved surface shape as a whole and a polygonal body shape having six or more corners in the circumferential direction. Further, a loosening prevention bolt formed by rounding the intersection of the inner surface of the skirt portion and the shaft portion in an R shape.

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