JP2003042129A - Locking screw component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively obtain a screw component exerting a certain locking effect with a simple structure. SOLUTION: In the screw component 1 comprised of a head portion 2 and a leg portion 4 formed of a screw thread 3, a projection 11 projecting in a pyramid-shape is arranged on a seat surface in the circumferential direction at a plurality of equal intervals. Since a ridged line 12 of the projection 11 is a locking screw component turning to a screw-fastening rotative direction, when the locking screw component is fastened to a work applied with corrosion preventive treatment by means of a special organic film for making influence to an environment reduced in recent years, a frictional coefficient is increased right before seating of the screw component, and the projection is cut into the work by canceling slippage and by surely breaking the surface of the work. Further, the destruction of a female screw is hardly produced so that a axial force generated when completing fastening of the screw is not suddenly increased from a preset value. Furthermore, cutting-into the work by the projection is facilitated so that the ridged line of the projection existed in the screw- fastening rotative direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a locking screw part which prevents a screw part fastened to a work from loosening due to vibrations and allows the seat surface of the screw part to be seated while scraping the surface film of the work. .

[0002]

2. Description of the Related Art At present, workpieces are fixed to each other so that the fixed state is prevented from being loosened due to loosening of a fastening member, that is, the fastening action of a screw part as a fastening member is not loosened due to vibration or impact. , Mainly apply various processing to the threads of screw parts and use adhesives. When the screw thread is processed to have a special shape in this way, the thread of the threaded part acts on the female thread formed on the workpiece when this threaded part is tightened, generating an axial force to generate the internal thread. It is made difficult to loosen by increasing the contact resistance with. In this case, it is necessary to make a notch or the like so that the screw thread fits even the slightest amount of the internal thread, and this may reduce the strength of the screw thread. Further, when an adhesive is used between the screw part and the work, once it is loosened, it cannot be reused as it is, and it is necessary to newly use the adhesive each time. In addition, this adhesive may not be able to exert an adhesive effect at all depending on the material of the work, so it is necessary to confirm the material of the work in advance and to confirm the effect before use.

Recently, many screw parts have been used to solve this problem and to easily obtain a locking effect. Among them, the one that is widely used is Jitsuko Sho 53-4060.
There is one disclosed in Japanese Patent No. As shown in FIG. 7 and FIG. 8, this is because the protrusion 111 is formed on the seat surface 110 of the head 102 that constitutes the screw part 101 on the same circumference, and the surface of the work when the screw part 101 is fastened to the work. When the head seating surface 110 is seated on the head, the protrusions 111 bite into the work surface to prevent loosening. In addition to this, there is also one disclosed in Japanese Utility Model Publication No. 54-930, in which a seat portion (not shown) having a diameter larger than the head diameter is integrally formed on the head seat surface of a screw component. In the vicinity of the outer periphery of the seat portion, a large number of tooth-shaped projections (not shown) are formed so as to slide on the surface of the work when tightened with screws and bite into the work when loosened.

[0004]

However, in the case where the projections that simply bite into the surface of the work are formed as in these conventional examples, the effect is comparatively obtained when the surface of the work is not hardened. However, in the case of using it on a work that has reduced the environmental impact as much as possible in recent years, that is, the corrosion prevention treatment method is often used in the production of the work from the chromium treatment which has been often used until now. The special organic composite coating that does not use chromium, which is the cause of this, has been replaced by this, and for this reason, the surface of this coated workpiece has a hardness equivalent to that of chromium, and the friction coefficient is low, causing slippage. The current situation is that it has become easier. As a result, the axial force generated when the screw tightening is completed tends to be higher than the set value, and the female screw is easily broken. Also, when using a conventional threaded component with a protrusion, the tip of the protrusion is worn and slippage occurs, and it is not possible to scrape the surface of the work with this protrusion, and it is possible to let this protrusion cut into the work sufficiently. Can not. Moreover, since all the positions of these protrusions are formed on the bearing surface on the same circumference, all the protrusions bite into the location on the same circumference of the workpiece, and even if many protrusions are formed. Problems arise such that only some of the protrusions act effectively, the necessary locking action cannot be obtained, and the pressing action of each protrusion is low.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a threaded component which has a simple structure and exhibits a reliable locking effect, at a low cost.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a screw part comprising a head portion 2 with which a driver bit engages and a leg portion 4 integrally formed with a screw thread 3 in a head seat surface. This is achieved by providing a plurality of protrusions 11 protruding in a pyramidal shape in the circumferential direction at 10 at equal intervals in the circumferential direction, and providing a locking screw part in which one ridge line 12 of the protrusion 11 faces the screw tightening rotation direction. It Further, this object can be achieved even in the case of the locking screw component having the projections 11 having different distances from the center of the screw component 1 in the above configuration. Further, in order to achieve the above-mentioned object, in addition to these configurations, the protrusion 11 has a higher protruding height as it gets closer to the center side of the screw component 1, so that a rapid increase in torque before tightening is completed. By providing the loosening set screw part in which the protrusion 11 has a triangular pyramid shape, it is possible to easily dig into the surface of the work 20.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
It will be described with reference to FIG. In FIG. 1, 1 is a head 2
And a leg portion 4 integrally formed with the head portion 2 and having a thread 3 around the head portion 2. Head 2 of this screw part 1
A drive hole 5 in the shape of a cruciform conical groove that engages with a driver bit (not shown) is formed on the center line of the leg 4.
The drive hole 5 of the head 2 has a cross-shaped conical groove shape, but is not limited to this, and may have, for example, a square shape, a hexagonal shape, or another groove or hole shape, and is a generally popular shape. If so, nothing is limited to this. On the other hand, on the outer circumference of the head 2, a hexagonal drive unit 6 is provided.
The drive portion 6 is suitable for transmitting a relatively large driving force as in the conventional case. The driving unit 6 may also have a polygonal shape such as a quadrangle or a pentagon other than the hexagonal shape.

A disc-shaped seat portion 7 having a diameter larger than the head portion is formed on the lower surface of the head portion 2, and a substantially triangular shape having a smaller diameter than the head portion 2 is formed on the center line of the seat portion 7. The leg portion 4 having a shape is integrally formed. The leg 4 is formed with threads 3 having a predetermined pitch, and the tip end thereof is slightly tapered so that it can be screwed into the prepared hole of the work 20 shown in FIG. As a result, the female screw 21 is inserted into the prepared hole of the work 20.
It is possible to tighten screws while forming. Further, a projection 11 having a sharp tip is formed on the seat surface 10 of the seat 7, and the projection 11 has a triangular pyramid shape as shown in FIG. By forming the protrusion 11 in the shape of a triangular pyramid, the ridge line 12 can be formed at an acute angle.
This shape is most suitable because it can bite into the work piece 20 in 2, but it may be a polygonal pyramid shape such as a quadrangular pyramid. Moreover, one ridgeline 12 (see FIG. 4) of this projection 11 is oriented in the screw tightening rotation direction,
As a result, the action of biting into the surface of the work 20 is smooth.

On the other hand, the projection 11 is, as shown in FIG.
The closer to the center of the screw component 1, the higher the height thereof, and the farther from the center, the lower the height. As a result, when the seat surface 10 is seated on the surface of the work 20, a sharp increase in the tightening torque does not occur. In the present embodiment, these projections 11 are arranged at quadrants on the circumference, and these four projections 11 are not on the same circumference, and the distance from the center of the screw component 1 is They are provided on different circles. Therefore, these protrusions 11 are in contact with different positions on the surface of the work 10. Although the number of the protrusions 11 is normally four, the number of protrusions 11 may be three, five, or the like.

Further, FIGS. 5 and 6 show another embodiment of the present invention, in which a head 2 having a driving hole 5 for engaging a driver bit is formed integrally with the head 2. This is a threaded component 1 in which a normal thread 3 is formed on a columnar leg portion 4. On the seating surface 10 of the head 2, the triangular pyramid-shaped protrusions 11 similar to those in the above-described embodiment are formed in the same arrangement. Thus, these projections 11 can be applied to the seating surface of any screw or bolt, and the same effect can be obtained in the nut.

When the loosening set screw component 1 having such a shape is fastened to the prepared hole or the female screw 21 formed in advance on the work 20, as shown in FIG.
The screw component 1 is tightened until the seat surface 10 contacts the surface of the work 20. At this time, since the ridge line 12 of the protrusion 11 faces the screw tightening rotation direction, the protrusion 11 closest to the center line of the screw component 1 first comes into contact with the surface of the work 20 to start biting. Since the tightening work is continued in this manner, the projections 11 located at positions distant from the center of the screw component 1 start contacting one after another and bite into the work 20.

After this, the bearing surface 10 of the screw component 1 is attached to the work 2.
Seated at 0 and the tightening work is complete. In this work, the screw tightening torque gradually increases from the first contact of the projection 11 to the seating of the seat surface 10, so that the tightening torque can be stably and accurately obtained and the loosening prevention effect can be secured. become.

[0013]

As is apparent from the above-described embodiments, the present invention provides a threaded component 1 including a head portion 2 with which a driver bit is engaged and a leg portion 4 having a screw thread 3 formed thereon. A plurality of protrusions 11 protruding in a pyramid shape are provided on the circumference 10 at equal intervals in the circumferential direction, and one ridge line 12 of the protrusion 11 is a locking screw part in which the screw tightening rotation direction is directed. When tightened on a work that has been treated to prevent corrosion by using a special organic coating that reduces the effect of even a little, the friction coefficient rises immediately before the seating of the screw part, slipping is eliminated and the work is surely done. It is possible to break the surface and bite the protrusion into the work. Further, the axial force generated at the time of completion of screw tightening does not suddenly become higher than the set value, so that the female screw is unlikely to break. Furthermore, since the ridge line of the protrusion is in the screw tightening rotation direction, it is easy to bite.

Moreover, since the projections are all different in distance from the center of the screw part, they do not act on the same portion of the work as in the conventional case, and each of them can bite into the work independently and surely loosen. A stopping action is obtained. Furthermore, the protrusion height increases as it gets closer to the center of the threaded part, so that the protrusion gradually comes into contact with different positions on the workpiece surface, and therefore the tightening torque increases sharply. This reduces the amount of tightening work, and increases the axial force of the screw components after tightening. In addition, since the height of the protrusions is lower toward the outside of the seat surface in this way, even if the protrusions that bite first wear, the protrusions with sharp angles bite one after another, so that the loosening prevention effect is high. In particular, since the protrusion has a triangular pyramid shape, its ridgeline becomes an acute angle, which can surely bite into the work covered with the special organic composite coating, and can be used for parts suitable for the environment. A peculiar effect such as providing a screw part can be obtained.

[Brief description of drawings]

FIG. 1 is a front view of a screw part showing an embodiment of the present invention.

FIG. 2 is a bottom view of the screw component shown in FIG.

FIG. 3 is an enlarged sectional view of an essential part showing a screwed state of the present invention.

FIG. 4 is an enlarged development view of essential parts showing the height relationship of the protrusions.

FIG. 5 is a front view showing another embodiment of the present invention.

6 is a bottom view of the screw component shown in FIG.

FIG. 7 is a front view of a conventional example.

8 is a bottom view of the conventional example shown in FIG.

[Explanation of symbols]

1 screw parts 2 heads 3 screw threads 4 legs 5 drive hole 6 drive 7 seat 10 seat 11 protrusions 12 ridges 20 work 21 female screw

Claims (4)

[Claims] 1. A screw part comprising a head part (2) with which a driver bit is engaged and a leg part (4) integrally formed with a screw thread (3), wherein a head seat surface (10) is provided. A loosening prevention screw component characterized in that a plurality of protrusions (11) protruding in a pyramidal shape are provided at equal intervals in the circumferential direction, and one ridgeline (12) of the protrusions faces the screw tightening rotation direction. 2. The lock screw component according to claim 1, wherein the protrusions have different distances from the center of the screw component. 3. The locking screw component according to claim 1 or 2, wherein the protrusion has a higher protrusion height as the protrusion is closer to the center side of the screw component. 4. The locking screw part according to claim 1, 2 or 3, wherein the protrusion has a triangular pyramid shape.