JPH034765B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a locking bolt for a female threaded hole.

[Prior Art] Conventional locking bolts have been designed to increase the frictional resistance by increasing the contact area of the threaded portion with the screwed portion in order to obtain the locking effect. In order to increase the contact area between the threaded part and the threaded part, the pitch of the thread in the threaded part should be made finer, or the precision of the threaded part should be increased to increase the contact area between the threaded part and the threaded part. Many measures are used to reduce the gap. However, in order to obtain the locking bolt effect by these means, it is necessary to provide a large number of highly accurate threads on the bolt, which is disadvantageous in that it takes a lot of time and money.

In addition, as a relatively simple method for obtaining the above-mentioned locking effect, a method has been considered in which a high torque is applied to the incompletely threaded portion at the final end of the bolt thread to obtain high locking friction resistance. However, when a bolt made by this method is used in a device that is subject to continuous severe impact,
In addition to this drawback, in order to apply high torque to the incompletely threaded portion and obtain anti-loosening frictional resistance, the incompletely threaded portion is It has the disadvantage that it is easily damaged and cannot withstand repeated use.

[Problems to be Solved by the Invention] The purpose of the present invention is to obtain a high locking effect even if the screw pitch is rough and the screw engagement accuracy is low, and to maintain a high locking effect even after repeated use. To provide a locking bolt for a female threaded hole that can be maintained for a long time.

[Means for solving the problem] According to the present invention, the object is to
a through hole provided from one end of the bolt body to the other end; a female taper portion provided at one end of the first bolt body; and a first male threaded portion provided in the first bolt body. A slit is provided along the axis at one end of the first bolt body in order to enable the diameter of the first male thread to be expanded, and a slit is inserted into the through hole and is longer than the first bolt body. a second bolt body, a male taper portion provided at one end of the second bolt body in correspondence with a female taper portion at one end of the first bolt body, and a second bolt body protruding from the first bolt body. A second bolt is attached to the second male threaded portion provided at the other end, and the second male threaded portion is moved relative to the second male threaded portion in the through hole toward the female tapered portion to expand the diameter of the first male threaded portion. This is achieved by a locking bolt for a female threaded hole having a locking nut screwed onto the second male threaded portion of the main body.

According to a preferred feature of the invention, at least one of the female tapered portion and the male tapered portion is formed by a tapered washer.

[Specific Example] The present invention will be described in more detail below based on a specific example.

According to FIGS. 1, 2, and 3, the locking bolt 1 for a female threaded hole has a hexagonal head 7, a male threaded portion 8 as a first male threaded portion, and a tip end surface 18 of the male threaded portion.
The first bolt body 9 has a through hole 11 along the axis 10 of the bolt body 9. A slit 12 is provided in the male threaded portion 8 symmetrically with respect to the axis 10 from a distal end surface 18 of the male threaded portion 8 in a direction along the axis 10. The number of slits 12 is not limited to two,
As shown in FIG. 7, there may be three or more, or conversely, there may be one, and there is no need to be parallel to the axis 10.
The through hole 11 is provided with a tapered surface 35 whose diameter decreases in the direction along the axis 10 from the tip end surface 18 . The locking bolt 1 further includes a tapered surface 17 as a tapered portion whose diameter decreases from the countersunk surface 14 side as shown in FIG. 4A, and a second tapered surface 17.
A second male threaded portion 15 as a male threaded portion of
It has a countersunk head bolt 13 as a bolt body, and this flat head bolt 13 has a tapered surface 3 of a through hole 11 provided on a distal end surface 18 of the first male threaded portion 8.
5 so that the tapered surface 17 of the countersunk head bolt 13 can come into contact with it, and so that the male threaded portion 15 protrudes from the other opening 20 of the through hole 11, that is, the opening 20 provided on the hexagonal head 7. The protruding portion of the male threaded portion 15 is fastened with a nut 16 having a locking function as a tightening device. The tapered surface 17 may be provided with a groove 28 as shown in FIG.
By providing the groove 28, the area of contact with the tapered surface 35 of the through hole 11 can be reduced, making it easier to move the countersunk bolt 13 in the axial direction. movement in the rotational direction can be prevented. The nut 16 and the male threaded portion 15 of the countersunk head bolt 13 may be either left-handed or right-handed, but preferably have a thread direction opposite to that of the male threaded portion 8.

A female threaded hole 5 that fits the male threaded portion 8 of the locking bolt 1 is provided on the surface 4 side of the attached portion 3 .

The mounting member 2 is provided with a through hole 6 having a diameter larger than the maximum thread diameter of the male threaded portion 8 of the locking bolt 1 and smaller than the maximum diameter 21 of the hexagonal head 7 of the locking bolt 1. .

The locking bolt for a female threaded hole of the present invention has a tapered surface 17 of a countersunk bolt 13 connected to a first bolt body 9.
abutting against the tapered surface 35 on the side of the male threaded portion 8 having the slit 12 of the through hole 11 along the axis 10 of the
As the countersunk head bolt 13 moves in the direction of the axis 10, the diameter of the male threaded part 8 is changed to increase the contact pressure between the male threaded part 8 and the female threaded hole 5, which is the threaded part of the male threaded part 8. By changing the contact area, the locking effect can be adjusted.

To explain in more detail, the procedure for fixing the mounting member 2 onto the part to be mounted 3 is to first place the mounting member 2 on one surface 4 of the part to be mounted 3, and then
are set so that the through holes 6 and the female threaded holes 5 of the attached part 3 are aligned with each other. The countersunk head bolt 13 of the locking bolt 1 is not tightened with the nut 16, that is, the slit 12 of the male threaded portion 8 of the locking bolt 1 is not pushed wide by the tapered surface 17 of the countersunk bolt 13. In this state, the male threaded portion 8 of the locking bolt 1 is inserted into the through hole 6 of the mounting member 2, and then the head bearing surface 22 of the hexagonal head 7 of the locking bolt 1 comes into contact with one surface 27 of the mounting member 2. Screw the threaded part 8 into the female threaded hole 5 of the mounted part 3 until the end.

With the head bearing surface 22 in contact with one surface 27 of the mounting member 2, the locking nut 16 as a tightening device installed on the male threaded portion 15 of the countersunk head bolt 13 of the locking bolt 1 is next inserted. As it is tightened, the countersunk head bolt 13 moves along the axis 10 direction, and as the countersunk head bolt 13 moves, the tapered surface 17 of the countersunk bolt 13 comes into contact with the tapered surface 35 of the through hole 11. As a result, the slit 12 is pushed out and the diameter of the male threaded portion 8 is expanded, and the male threaded portion 8 and the female threaded hole 5 are expanded.
The contact pressure increases, creating strong frictional resistance.

Further, FIG. 5 shows another specific example of a locking bolt for a female threaded hole using a stud bolt 3 in which a first bolt body 8 is provided on the entire outer peripheral surface of the first bolt body. A locking bolt for use is shown. One end 32 of this stud bolt 31 is provided with a locking mechanism similar to the locking bolt for a female threaded hole shown in FIG. The other end 33 has a mounting nut 30 for mounting the mounting member 2 to the mounted part 3 via the stud bolt 31.
is attached to the other end 33, and a first
A slit 25 and a tapered surface 36 similar to the slit 12 and tapered surface 35 provided in the locking mechanism are provided. The stud bolt 31 is provided with a through hole 38 along the axis 37 of the stud bolt 31, similar to the bolt body 9 shown in FIG. 1, and the countersunk bolt 13 is mounted in this through hole 38. The male threaded portion 15 of the countersunk bolt 13 protruding from the other end 33 side of the stud bolt 31 has a
The tapered washer 24, which has a tapered surface 26 as shown in FIG. The locking nut 16 is attached to the slit 25 of the stud bolt 31, the tapered surface 36, and the tapered washer 24.
Together with this, it constitutes a second locking mechanism. When the locking nut 16 is tightened in this state, the tapered washer 24 moves along the axis 37 in a direction where the tapered surface 26 strongly contacts the tapered surface 36 of the other end 33 of the stud bolt 31. As the washer 24 moves, the slit 25 is pushed and expanded, and due to this pushing and expansion, the diameter of the male threaded portion 8 is expanded,
This male threaded portion 8 and the female threaded portion 3 of the mounting nut 30
The degree of adhesion with 9 increases, creating strong frictional resistance.

As mentioned above, the locking bolt for a female threaded hole in FIG. 5 is provided with a second locking mechanism in addition to the first locking mechanism of the locking bolt in FIG. 1, and is larger. It becomes possible to produce a loosening prevention effect.

In the above specific example, the case where there are two slits aligned in the axial center direction has been explained, but the present invention is not limited to two slits in the axial center direction. It is preferable to set it arbitrarily depending on the purpose.

[Effects of the Invention] With the above configuration, when the locking bolt for a female threaded hole of the present invention is installed in the female threaded hole 5, the first bolt body is screwed into the female threaded hole. Even if the locking nut screwed onto the second male thread of the second bolt body is tightened after the first bolt body is tightened, the second bolt body itself will not loosen. The second bolt body moves in the axial direction without rotation, so that the male taper portion of the second bolt body fitted into the female taper portion of the first bolt body connects with the first male thread of the first bolt body. The diameter of the part can be expanded.

In other words, when the female taper section moves relative to the male taper section in the axial direction to expand the diameter of the first male thread section, there is a relative gap between the female taper section and the male taper section. Since no rotation occurs, it is possible to prevent a decrease in the frictional force between the female taper portion and the male taper portion, and as a result, the locking nut can be tightened even more firmly, so that the first male thread portion is further tightened. The diameter can be increased, and the locking action of the first bolt body can be reliably increased.

At the same time, it is possible to minimize the occurrence of scratches, etc. at the contact area between the female taper part and the male taper part, that is, damage, so even if the locking bolt is repeatedly used, the initial loosening function will not deteriorate. It can be suppressed relatively gently.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of the mounting member attached to the part to be mounted using a locking bolt for a female threaded hole, and Figure 2 is a cross-sectional view of the locking bolt for a female threaded hole viewed from the direction shown in Figure 1. The explanatory diagram, Figure 3, is
Fig. 4 is a perspective view of a bolt with a tapered part, and Fig. 5 is an explanatory diagram of a locking stud bolt for a female threaded hole viewed from the direction shown in Fig. 1. 6 is a perspective view of the taper washer, and FIG. 7 is a cross-sectional view of the mounting member attached to the part to be attached, and FIG. It is an explanatory view of a modification. 1... Locking bolt, 5... Female threaded hole, 8
...Male thread of the first bolt, 9...First bolt, 10...Axis center, 11...Through hole of the first bolt, 12...Slit, 13...Countersunk bolt,
15...Male thread of countersunk bolt, 16...Loosening nut, 17...Tapered surface, 19...Opening.

Claims (1)

[Scope of Claims] 1. A first bolt body; a through hole extending along the axis of the first bolt body and extending from one end of the first bolt body to the other end;
A female taper portion provided at one end of the first bolt body, a first male threaded portion provided in the first bolt body, and a diameter of the first male threaded portion to be expanded. , a slit provided along the axis at one end of the first bolt body, and a second bolt body inserted into the through hole and longer than the first bolt body.
a male taper portion provided at one end of the second bolt body in correspondence with a female taper portion at one end of the first bolt body;
a second male threaded portion provided at the other end of the second bolt body protruding from the bolt body; and a second male threaded portion provided at the other end of the second bolt body protruding from the bolt body; A locking bolt for a female threaded hole, comprising a locking nut screwed onto a second male threaded portion of the second bolt body in order to expand the diameter of the first male threaded portion. 2. The locking bolt for a female threaded hole according to claim 1, wherein at least one of the female taper portion and the male taper portion is formed by a taper washer. 3. The locking bolt for a female threaded hole according to claim 1 or 2, wherein the locking nut is a locking nut.