JP5933770B2 - Fastener manufacturing method - Google Patents

Description

The present invention relates to a process for the preparation of fasteners, a method of manufacturing a fastener, in particular consisting of a bolt and a nut.

2. Description of the Related Art Conventionally, there is a loosening prevention structure in which two nuts are screwed into one bolt, that is, a so-called double nut, as a loosening prevention structure for a fastener. This is to prevent the rotation of the tightening nut in the loosening direction due to vibration or the like by the loosening prevention nut by screwing and tightening the loosening prevention nut following the tightening nut screwed into the bolt.

In this locking structure, a female screw with the same pitch is formed on both the tightening nut and the locking nut, and the male screw with the same pitch is screwed onto the bolt formed on the shaft, and the friction generated between the tightened nuts. It prevents the tightening nut from loosening by force.

The conventional fasteners according to such a structure can prevent the tightening nut from loosening to some extent, but if a large vibration is applied for a long time, the tightening nut and the locking nut cause a so-called rotation and loosen. there were.

Therefore, the present applicants previously devised a fastener capable of effectively preventing the nut from loosening due to vibration or the like, and filed a utility model registration application (Patent Document 1).
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In the fastener for which the utility model registration application has been filed, the shaft portion of the bolt is a main shaft portion and a thin shaft portion existing on the tip side thereof, a male screw of a coarse screw is formed on the main shaft portion, and the fine screw portion is formed. By forming a male screw of a fine screw on the radial shaft part, forming a female screw to be screwed to the coarse screw on the tightening nut, and forming a female screw to be screwed to the fine screw on the locking nut, A tightening nut is screwed onto the main body shaft, and a locking nut is screwed onto the small diameter shaft.
A fastener composed of a bolt and a nut.

According to the above-described fastener composed of a bolt and a nut, the pitch between the tightening nut and the locking nut is different, so that both nuts do not rotate, thereby effectively preventing the tightening nut from loosening. It was possible. In addition, since the coarse screw and the fine screw are not overlapped, the coarse screw has no defective portion, and the tightening nut to be screwed into the coarse screw can be strongly tightened, and the locking nut can be Since the fine screw to be screwed is formed on the thin shaft portion on the tip end side of the bolt, the fine screw does not get in the way when screwing the tightening nut.

Utility Model Registration No. 3179874

However, in the fastener disclosed in Patent Document 1 described above, when the fastening nut and the locking nut cannot move independently due to the frictional force between the nuts, Both nuts could not be rotated because the pitch was different, and it was possible to effectively prevent the tightening nut from loosening, but the locking nut that screwed into the fine screw for some reason loosened independently first. In that case, after that, the frictional force between the nuts that cause both nuts to rotate together will no longer work, and each nut may loosen independently. The dropout was a concern.

The present invention has been made in view of the above-described problems of the prior art, and the object thereof is to integrate a screwed tightening nut and a locking nut without changing the fastening workability, and to tighten the nut. An object of the present invention is to provide a method of manufacturing a fastener comprising bolts and nuts that can reliably prevent loosening of the fastener and, in particular, loosening of the fastener.

In order to achieve the above object, the present invention is a method for manufacturing a fastener described in the following (1) to (4).
(1) The bolt shaft portion is a main shaft portion and a thin shaft portion existing on the tip side thereof, a male screw is formed on the main shaft portion, and a male screw is formed on the main shaft portion on the thin shaft portion. A narrower-pitch male screw is formed, a female screw that is screwed to the male screw formed on the main body shaft portion is formed on a tightening nut, and a female screw that is screwed to the male screw formed on the small-diameter shaft portion is by forming the locking nut is screwed a nut tightened to the main shaft unit, the fastener comprising a bolt and a nut so as screwing the nut retaining loose the small-diameter shaft portion, the tightening nut And a method of manufacturing a fastener comprising a bolt and a nut having engaging means for preventing relative rotation of the two nuts on the contact surface of the locking nut, wherein the engaging means includes the tightening nut. Or the above locking nut A saw blade-like projection formed in advance on one of the contact surfaces and the other of the contact surface of the tightening nut or the locking nut by the saw blade projection when the locking nut is tightened to the tightening nut. A method for manufacturing a fastener comprising a bolt and a nut, characterized in that the fastener is formed of a digging-up protrusion .
(2) A saw blade-like projection is formed on the contact surface of the locking nut with the tightening nut, and the tightening nut is made of a material having a hardness of 20 HRC or less. The manufacturing method of the fastener which consists of a volt | bolt and a nut as described in 1) .
(3) The saw blade-like protrusion is formed in an annular shape on the contact surface of the locking nut, with the blade tip facing in the same direction as the tightening rotation direction of the locking nut, The manufacturing method of the fastener which consists of a volt | bolt and a nut as described in said (1) or (2) characterized by the above-mentioned.
(4) Any of (1) to (3) above, wherein the male screw formed on the main body shaft portion is a coarse screw, and the male screw formed on the small-diameter shaft portion is a fine screw. A method for producing a fastener comprising the bolt and nut according to claim 1.

According to the method for manufacturing a fastener comprising a bolt and a nut according to the present invention described above, the fastener having an engaging means for preventing the relative rotation of both nuts on the contact surfaces of the tightening nut and the locking nut. since it is possible to manufacture the, come together and tightening nut and self-locking nut, a state that can not be around independently. On the other hand, a fastener comprising a bolt and a nut, which is a subject of the present invention, has a pitch between a tightening nut that is screwed into a male screw formed on the main body shaft portion, and a male screw of the main body shaft portion that is formed on the small-diameter shaft portion. Therefore, the tightening nuts and the locking nuts are in a state where they cannot be rotated. Both actions of the fastener of the present invention described above, that is, the action of integrating the tightening nut and the locking nut by the engaging means, and the action of providing a pitch difference to prevent the rotation of the clamping nut and the locking nut. Together with this, it is possible to manufacture a fastener that can reliably prevent the nut from loosening.

It is the side view which showed one Embodiment of the volt | bolt used in this invention. It is the figure which showed one Embodiment of the clamping nut used in this invention, Comprising: (a) is the perspective view seen from upper direction, (b) is a half-section side view. It is the figure which showed one Embodiment of the locking nut used in this invention, Comprising: (a) is the perspective view seen from the downward | lower direction, (b) is the concept which expanded and showed the A section of the said (a) figure. A partially enlarged side view, (c) is a bottom view. FIG. 4 is a view showing an embodiment of a fastening structure using the bolt, the tightening nut, and the locking nut shown in FIGS. 1, 2, and 3, before screwing the clamping nut and the locking nut to the bolt; It is the conceptual half-section side view which showed the state. FIG. 5 is a conceptual half-sectional side view showing a state in which a fastening nut is screwed onto a bolt in the fastening structure shown in FIG. 4. In the fastening structure shown in FIG. 4, (a) is a conceptual half-sectional side view showing a state in which a tightening nut and a locking nut are screwed onto a bolt, and (b) is a portion B in FIG. It is the conceptual partial expansion side view which expanded and showed.

Hereinafter, an embodiment of a method for manufacturing a fastener including a bolt and a nut according to the present invention will be described in detail with reference to the drawings.

The bolt 1 used in the present invention has a head portion 2 and a shaft portion 3 as shown in FIG. The head 2 has a substantially hexagonal column shape and is suitable for tightening with a tool such as a spanner or a hexagon wrench. The shaft portion 3 includes a main body shaft portion 3a and a small-diameter shaft portion 3b existing on the tip side thereof, and a male screw of a coarse screw 4a is formed on the main body shaft portion 3a, and the small-diameter shaft The male screw of the fine screw 4b is formed in the part 3b. In addition, since the shaft diameter of the main body shaft portion 3a is smaller than that of the small diameter shaft portion 3b, the male screw on the small diameter shaft portion side is the male screw on the main body shaft portion side even when male screws of coarse threads are formed on both. Since it becomes a thing of a narrower pitch, that may be sufficient. In short, it is sufficient that a male screw having a narrower pitch than the male screw formed on the main body shaft portion 3a is formed on the small diameter shaft portion 3b. However, when the male screw of the coarse screw 4a is formed on the main body shaft portion 3a and the male screw of the fine screw 4b is formed on the small-diameter shaft portion 3b as in the embodiment, the pitch is greatly different. Therefore, in the following, this embodiment will be described.

The small-diameter shaft portion 3b is preferably formed to a shaft diameter of 60 to 90% of the shaft diameter of the main body shaft portion 3a, and more preferably 70 to 85%. This is 6
When a thin thin shaft portion of less than 0% is formed, the strength of the thin shaft portion is weakened, and a locking nut that is screwed into the fine screw 4b formed on the thin shaft portion; This is not preferable because it is difficult to ensure a sufficient contact surface with the tightening nut that is screwed into the coarse screw 4a formed in the main body shaft portion. On the other hand, when a thin shaft portion exceeding 90% is formed, the fine screw formed on the thin shaft portion when the tightening nut is inserted and screwed into the coarse screw 4a formed on the main shaft portion. 4b is not preferable because it may interfere.

  Moreover, it is preferable that the pitch of the male screw formed in the said thin diameter shaft part 3b is formed in 30 to 70% of the pitch of the male screw formed in the main body shaft part, and is formed in 45 to 60%. More preferably. This is not preferable in terms of fastening work when a male screw having a narrow pitch of less than 30% is formed on the thin-diameter shaft portion 3b, and the progress of the locking nut screwed into the male screw is slow. On the other hand, when a male screw that exceeds 70% and does not differ much from the pitch of the male screw formed on the main body shaft portion is formed on the small-diameter shaft portion 3b, the tightening nut and the locking nut may cause rotation. It is not preferable because there is.

Note that the coarse screw 4a is not necessarily formed over the entire length of the main body shaft portion, and may be formed only above the main body shaft portion 3a as illustrated.

As shown in FIG. 2, the tightening nut 5 used in the present invention has a substantially hexagonal column shape and is suitable for tightening with a tool such as a spanner or a hexagon wrench. Further, on the inner peripheral wall surface, a female screw 6 that is screwed into a coarse screw 4a formed on the main body shaft portion 3a of the bolt 1 is formed.

An annular protrusion 7 is formed on the upper surface of the tightening nut 5 (a contact surface with a locking nut described later). The annular projection 7 is formed so that the knitting force is concentrated and applied with a small contact area so that it can be easily carved by a saw blade-like projection formed on the contact surface of the locking nut described later. From this point of view, the width w of the annular protrusion 7 is preferably 15 to 65% of the maximum thickness W of the nut, and the height h is preferably about 5 to 15% of the height H of the nut. For example, in the case of a JIS standard M16 nut, it is preferable to provide an annular protrusion having a width of about 3 mm and a height of about 1.5 mm.

  The annular protrusion 7 is not necessarily provided. In particular, when the material of the tightening nut 5 is made of a soft material, for example, a hardness of 20 HRC or less, an indentation mark due to the saw blade protrusion is easily formed. It is not necessary to provide an annular protrusion.

As shown in FIG. 3, the loosening prevention nut 8 used in the present invention has a substantially hexagonal column shape and is suitable for tightening with a tool such as a spanner or a hexagon wrench. On the inner peripheral wall surface, a female screw 9 is formed which is screwed into a fine screw 4b formed on the thin shaft portion 3b of the bolt 1.

Further, on the lower surface of the locking nut 8 (the contact surface with the tightening nut), the saw blade projection 1
0 is formed in an annular shape with the cutting edge directed in the same direction as the tightening rotation direction of the locking nut. That is, an upright surface P upstanding by 18 radial radial lines that divide the circumference into 18 equally with the female screw 9 as the center, and an inclined surface S that descends from the top (blade edge) of the vertical surface P to the adjacent radial line The eighteen saw blade-like projections 10 formed in the above are continuously formed with the cutting edge directed in the clockwise direction.
It is preferable that the saw-tooth projection 10 has increased hardness by induction hardening or the like.

  In addition, in this embodiment, although it has the structure which provided the several saw blade-like processus | protrusion 10 radially centering on the internal thread, it is not limited to this, You may be discontinuous. Further, the number of saw blade projections is not limited to 18 at all.

The height t of the vertical surface P of the saw blade projection 10 is formed to be larger than the pitch distance of the fine screw 4b, and the inclination angle α of the inclined surface S of the saw blade projection 10 is the thread cutting of the fine screw 4b. It is formed larger than the angle. Thereby, as will be described later, the locking nut and the tightening nut are firmly integrated, and the nut can be reliably prevented from loosening. From this point of view, the height t of the vertical surface P of the saw blade protrusion 10 and the inclination angle α of the inclined surface S of the saw blade protrusion 10 are as follows.
Is 1.5 to 5 from the pitch distance of the fine screw 4b or the threading angle of the fine screw 4b.
The size is preferably about 2.5 times.

When the bolt 1, the tightening nut 5, and the locking nut 8 described above are used and the object to be fastened is fastened, it may be performed in the same manner as before.
That is, as shown in FIG. 4, first, the shaft portion 3 of the bolt 1 is inserted into the through holes 11a and 12a formed in the members 11 and 12 to be fastened. At this time, a washer 13 is interposed as required.

Subsequently, as shown in FIG. 5, the coarse screw 4 a formed on the main body shaft portion 3 a of the bolt 1,
The members 11 and 12 are fastened by inserting and screwing the tightening nut 5 and tightening firmly. At this time, since the fine screw 4b existing at the tip of the bolt 1 is formed on the thin shaft portion 3b having a small diameter, there is no obstacle when the tightening nut 5 is screwed to the coarse screw 4a. There is nothing. Further, the coarse screw 4a formed in the main body shaft portion 3a is not easily deformed because there is no missing portion, and the tightening nut 5 can be strongly tightened.

Subsequently, as shown in FIG. 6, the fine screw 4 b formed on the small diameter shaft portion 3 b of the bolt 1,
The locking nut 8 is inserted and screwed into the upper surface of the tightening nut 5 screwed first. At this time, the saw blade projection 10 formed on the lower surface of the locking nut 8 (the contact surface with the tightening nut) is an annular projection formed on the upper surface of the tightening nut 5 (the contact surface with the locking nut). As shown in FIG. 6 (b), a protrusion 20 that contacts the inclined surface S of the saw blade protrusion 10 is formed on the surface of the annular protrusion 7.

After the locking nut 8 is tightened, the saw blade projection 10 on the locking nut side and the projection 20 formed on the tightening nut side by the saw blade projection mesh with each other, and the relative relationship between the two nuts. Thus, the tightening nut 5 and the locking nut 8 are integrated with each other and cannot be rotated independently. On the other hand, the tightening nut 5 screwed into the coarse screw 4a of the bolt 1 and the locking nut 8 screwed into the fine screw 4b of the bolt 1 have different degrees of progress due to rotation, and the clamping nut 5 and the locking nut With 8, it is in a state where it is not possible to cause a rotation. Both the above-described actions, that is, the action of integrating the tightening nut 5 and the locking nut 8 by the engaging means comprising the saw-toothed protrusion 10 and the protrusion 20 that has been dug up, and the tightening nut 5 with a pitch difference are provided. The combined action of blocking the rotation of the nuts 8 and the locking nuts 8 makes it possible to reliably prevent the nuts from loosening. In particular, in the above-described embodiment, the height t of the elevation surface P of the saw blade projection 10 is formed larger than the pitch distance of the fine screws 4b, and the inclination angle α of the inclined surface S of the saw blade projection 10 is. Is formed larger than the thread cutting angle of the fine screw 4b, the engagement state between the saw blade protrusion 10 and the protrusion 20 digged up by the saw blade protrusion is strong and highly reliable. As a result, the loosening prevention effect is significantly improved.

As mentioned above, although one Embodiment of the manufacturing method of the fastener which consists of the volt | bolt and nut which concerns on this invention was described, this invention is not limited to the above-mentioned embodiment at all, and is described in a claim. Naturally, various modifications and changes are possible within the scope of the technical idea of the present invention.

For example, in the above-described embodiment, a so-called hexagonal bolt having a substantially hexagonal column as the head 2 is shown as a bolt. However, a hexagon socket head bolt, an eye bolt, a butterfly bolt, a stud bolt, or the like may be used. Further, in the above embodiment, as the engagement means for preventing the relative rotation of the tightening nut 5 and the locking nut 8, the saw blade projection 10 provided on the locking nut side is tightened by the saw blade projection. Although the protruding portion 20 is formed by digging up on the nut side, the saw blade-shaped protrusion and the protruding portion formed by digging may be formed on opposite nuts. Furthermore, the configuration of the engaging means is not limited to the saw blade protrusion 10 and the protrusion 20 digged up by the saw blade protrusion shown in the above embodiment, but the tightening nut 5 and the locking nut 8 are tightened by the tightening force.
If it is the structure which can be made into the state which cannot be carried out by uniting, well-known various engagement means can be employ | adopted. Moreover, although the male screw of the coarse screw 4a was formed in the main body shaft part 3a and the male screw of the fine screw 4b was formed in the thin diameter shaft part 3b, the main body shaft part 3a was described as the thin diameter shaft part 3b. Because the shaft diameter is smaller, even when male screws with coarse threads are formed on both, the male screw on the small-diameter shaft portion side has a narrower pitch than the male screw on the main shaft portion side, so that may be sufficient, In short, it is sufficient that a male screw having a narrower pitch than the male screw formed on the main body shaft portion 3a is formed on the small diameter shaft portion 3b.

As described above, the method for manufacturing a fastener including a bolt and a nut according to the present invention can be used to fasten components used in an environment in which vibration is applied, for example, a car, a ship, an aircraft, and a laundry equipped with a motor. It can be widely used for fastening parts of home appliances such as machines.

DESCRIPTION OF SYMBOLS 1 Bolt 2 Head 3 Shaft part 3a Main body shaft part 3b Small diameter shaft part 4a Coarse screw 4b Fine screw 5 Tightening nut 6 Female screw 7 Annular protrusion 8 Loosening prevention nut 9 Female screw 10 Saw blade-like protrusion 11, 12 Tighten Power member 11a, 12a Through hole 13 Washer

Claims (4)

The shaft portion of the bolt is a main shaft portion and a thin shaft portion existing on the tip side thereof, a male screw is formed on the main shaft portion, and the pitch is larger than that of the male screw formed on the main shaft portion. In addition to forming a narrow male screw, a female screw that is screwed to the male screw formed on the main body shaft portion is formed on the tightening nut, and a female screw that is screwed to the male screw formed on the small-diameter shaft portion is a locking nut by forming the said screwed a tightening nut on the main shaft unit, said in fastener comprising a bolt and a nut so as screwing the lock nut loose small diameter shaft portion, the fastening nut and the loosening A method of manufacturing a fastener comprising a bolt and a nut having engaging means for preventing relative rotation of both nuts on a contact surface of a locking nut, wherein the engaging means is the tightening nut or the loosening Lock nut contact The saw blade projection formed on one side of the screw and the tightening nut of the locking nut to the tightening nut were dug up by the saw blade projection on the other of the tightening nut or the contact surface of the locking nut. A method for manufacturing a fastener comprising a bolt and a nut, wherein the fastener is formed by a protrusion . 2. A saw blade-like protrusion is formed on a contact surface of the locking nut with the tightening nut, and the tightening nut is made of a material having a hardness of 20 HRC or less. Of manufacturing a fastener comprising a bolt and a nut . The saw blade projection is formed in an annular shape on the contact surface of the locking nut, with the blade tip facing in the same direction as the tightening rotation direction of the locking nut, and the locking nut is in contact with the locking nut wherein the annular projection is formed on the surface, the production method of the fastener comprising a bolt and a nut according to claim 1 or 2. 4. The bolt according to claim 1, wherein the male screw formed on the main shaft portion is a coarse screw, and the male screw formed on the small-diameter shaft portion is a fine screw. A method for manufacturing a fastener comprising a nut.

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