JP2001271819A - Threadedly fastened locking mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To repeatedly use a mechanism to prevent threadedly fastened condition of a bolt and a nut from loosening, by relatively structuring the bolt and the nut, without using any other part, and by using elastic deformation rather than plastic deformation. SOLUTION: If a lock nut male screw part 2a of a lock nut 2 is screwed in a bolt screw part 1b of a bolt body 1 penetrating through a through-hole 3a of a body 3 to be fastened, an expanded inner wall part 2c of the lock nut at a taper tip opening part 2b pressingly abuts on an expanded outer wall part 1e of the bolt at a taper tip part 1c. In addition, if the lock nut 2 is threadedly advanced by increasing torque, the expanded inner wall part 2c of the lock nut goes over the expanded outer wall part 1e of the bolt based on elastic deformation and advances to a taper run off 1d, in order to form a fastened condition. Thereby, as long as inversely rotating external force having a considerably big torque is added, no loosening will be produced in the fastening condition of the lock nut 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method in which a bolt is fitted to an object to be fastened, and a nut is screwed and fastened to a male screw portion of the bolt protruding, so that the object to be fastened is brought into a fastening state. The present invention relates to a screw-fastened locking stopper formed by using a lock nut for preventing the nut from being loosened when doing so.

[0002]

2. Description of the Related Art As described above, in order to prevent unintentional loosening of a lock nut in a state of being fastened by a bolt and a lock nut, a locking mechanism having various structures has already been proposed. FIG. 5 and FIG. 6 show one of them. That is, the tip male screw portion b of the bolt main body a is provided with V-shaped grooves c, c in the axial direction at opposite positions on the peripheral surface thereof, while the lock nut d is provided with the nut portion e. And a thin-walled cylindrical portion f coaxially connected thereto. To use this, as shown in FIG.
After the nut portion e of the lock nut d is screwed into the tip male screw portion b, the thin cylindrical portion f is formed along the shape of the V-shaped grooves c, c as shown in FIG. Plastic lock to prevent the lock nut d from rotating unintentionally. Of course, the fastening end face e1 of the nut portion e,
An object to be fastened by an attaching plate or the like through which the bolt body a is penetrated is clamped by a fastening receiving surface (not shown) of the bolt body a. Here, in the above illustrated example, the tie plate is directly sandwiched between the fastening end surface e1 and the fastening receiving surface, but the tie plate is indirectly fastened between the above both with a spring or a washer interposed therebetween. Of course, there are things to do.

[0003] In addition to the first conventional example, a separately provided anti-rotation claw between the fastening member and the nut is brought into close contact with the fastening member and the nut, thereby making the nut unfit. A second conventional example in which intentional rotation is prevented is also known.

[0004]

According to the first conventional example described above, in order to lock the lock nut d as described above, a special tool for plastically deforming the thin cylindrical portion f is used. All special tasks will be indispensable,
Therefore, not only requires considerable labor and time, but also when it is desired to release the above-mentioned fastening state, it is necessary to use a special tool for cutting and peeling the thin-walled cylindrical portion f in close contact with the V-shaped groove c. Work is required and requires skill, which makes it difficult to ensure a consistent and satisfactory fastening condition at all times. As a result, the thin cylindrical portion f of the lock nut d has a problem that it cannot withstand the repeated use and a special alloy must be selected.

[0005] In addition, even in the second conventional example, a separate member such as a washer is required outside the nut.
The work for fastening the object to be fastened is troublesome, and the other member is also plastically deformed by the rotation preventing claw of the washer, so that satisfactory results have not been obtained in terms of repeated use.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned problems of the prior art. According to the first aspect of the present invention, a lock nut female screw of a lock nut is provided on a bolt male screw portion of a bolt body. Just by screwing the parts together, the lock nut bulging inner wall part of the lock nut can overcome the bolt bulging outer wall part formed at the fine tip on the tip side of the bolt male screw part by elastic deformation. You do it. As a result, in the screw-fastened state, the lock nut bulging inner wall can be overcome from the bolt bulging outer wall in the reverse direction by elastic deformation unless a considerable torque is applied to the lock nut to rotate the lock nut in the reverse direction. However, the resistance generated at this time can be utilized as a force for preventing undesired rotation of the lock nut. Thus, without using a separate member for preventing loosening such as the washer, and without having to plastically deform the thin-walled cylindrical portion or the like, merely rotating the lock nut with a somewhat strong force, It is an object of the present invention to secure a state of preventing loosening only by a simple and quick working process without skill, and to enable repeated use.

[0007] According to claim 2, the above-mentioned claim 1 is provided.
In contrast to the above configuration, a thin projection is protruded from the thick base end of the bolt main body, and the fastened body is pressed against the bolt receiving distal end surface of the thick base end to stably fasten the fastened body. And a tapered portion formed at the tip of the thinned tip of the bolt body so that the bolt body can be smoothly screwed into the lock nut. Part is formed so as to be in a penetrating state, so that the bolted body can be fastened without trouble even if the dimensions of the bolt body are long and short, and the lock nut is formed by the nut part and the thin cylindrical body. The additional object of the present invention is to not only reduce the weight but also eliminate excessive loss of resistance due to the elastic deformation of the inner wall portion 2c of the lock nut by connecting the lock nuts. It is.

[0008]

According to the present invention, in order to achieve the above object, according to the present invention, a thin base end portion, a bolt male screw portion, and a thin front end portion are sequentially formed from a base end side. A bolt nut, a lock nut having a female screw portion on the base end side and a lock nut having a thin tip end portion. The thin tip portion of the bolt body has a narrow relief portion and a bolt toward the distal end. A swelling outer wall portion is continuously provided, and a locknut swelling inner wall portion is formed at a thinned tip end portion of the lock nut, and protruded from a thinned tip portion of the bolt body through a through hole of a member to be fastened. The bolt nut female screw portion of the lock nut is screwed into the bolt male screw portion, so that the outer wall protruding portion of the bolt bulging outer wall portion is elastically deformed by the inner wall protruding portion of the lock nut bulging inner wall portion. And the base end of the lock nut bulging inner wall is The bolt body can freely enter the narrow relief portion, so that the object to be fastened is between the bolt receiving tip surface of the thick base end portion and the lock nut receiving base end surface of the lock nut female screw portion. It is an object of the present invention to provide a screw-fastening locking mechanism that is adapted to be fastened.

According to a second aspect of the present invention, there is provided an additional configuration of the first aspect, which is characterized in that a narrow base end portion, a narrow protrusion portion, and a bolt are sequentially formed from the base end side. A bolt main body having a male screw portion and a thinned distal end portion, a nut portion on the base end side, and a thinned cylindrical portion connected to the nut body, and are connected to the lock nut female screw portion of the nut portion. And a lock nut having a narrow tip end portion penetrating the thin cylindrical portion, and the thin tip portion of the bolt body has a narrow relief portion and a bolt bulging outer wall toward the tip side. Part and a tapered taper part are connected to each other, and the bolt body enters the lock nut female screw part from the thinned tip part through the opening of the fastened body, and the bolt male screw part is changed to the lock nut female screw part. , The outflow portion of the outer wall portion of the bolt bulging outer wall portion bulges the lock nut The inner wall outflow portion of the wall portion is overcome by elastic deformation, so that the base end side of the lock nut bulging inner wall portion can freely enter the narrow relief portion of the bolt body, and in the advanced state, the narrow tip of the bolt body is formed. Part, the tapered tapered portion advancing from the thinned distal end portion, whereby the body to be fastened by the bolt receiving distal end surface of the thick base end,
The lock nut female screw portion is fastened between the lock nut receiving base end face and the content thereof.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to FIGS. 1 to 3, which comprises a bolt main body 1 and a lock nut 2, and the bolt main body 1 has a thick base end portion 1a which is gradually narrowed from a base end side. , A bolt male screw portion 1b, and a thin tip portion 1c. The lock nut 2 is composed of a lock nut male screw portion 2a on the base end side and a thin tip end portion 2b coaxially and continuously provided therewith. I have it. A thin escape portion 1d and a bolt bulging outer wall portion 1e are continuously provided on the thin tip portion 1c of the bolt body 1 toward the tip end. In the embodiment shown in FIGS. An insertion tip 1f having a uniform diameter is continuously provided on the tip side.

Further, in the lock nut 2 described above,
A lock nut swelling inner wall portion 2c is provided at the thinned tip end portion 2b.
Here, the bolt main body 1 is protruded from the thinned tip portion 1c through the opening 3a of the fastened body 3 shown in FIG. 1, and a bolt male screw of the thinned tip portion 1c is formed. Part 1b
Then, the above-mentioned lock nut male screw portion 2a is screwed. When the screw advance reaches a certain degree, the lock nut bulging inner wall portion 2c comes into contact with the bolt bulging outer wall portion 1e to indicate the resistance to the screw advance, and the resistance gradually increases. If the rotation force is not increased, the screw cannot be screwed. Therefore, when the screw is advanced by increasing the torque, the above-described resistance gradually increases. At this time, the lock nut bulging inner wall 2c and the bolt bulging outer wall 1e are elastically deformed, so that the lock nut bulging inner wall is formed. The inner wall protruding portion 2d at the central portion in the longitudinal direction of 2c is
The outer wall protruding portion 1g formed at the central portion in the longitudinal direction of the bolt bulging outer wall portion 1e gets over the inner wall protruding portion 2d. At this time, the inner wall protruding portion 2d reaches the position of the narrow relief portion 1d of the bolt body 1. And thus sufficient tightening with the specified torque is possible. As a result, as can be understood from FIG.
And the lock nut receiving base end surface 2e of the lock nut female screw portion 2a is screwed and fastened. Here, the one illustrated in FIG.
However, it is needless to say that the fastening may be performed by interposing a spring or a washer (not shown).

In the screw-fastening and loosening prevention mechanism according to the first aspect of the present invention, when the above-mentioned fastening state is to be loosened, the lock nut 2 is rotated in the reverse direction to lock the state from the state shown in FIG. Nut bulging inner wall 2c is bolt bulging outer wall 1
e must be overcome by the elastic deformation, so that even if a rotational force in the loosening direction acts on the lock nut 2 due to vibration or other undesired external factors, the above-mentioned overcoming due to the elastic deformation may occur. The sufficiently large resistance generated at that time prevents the lock nut 2 from rotating unintentionally, so that the lock nut 2 can be prevented from loosening. And, by using the elastic deformation, if it is within the range of the elastic deformation and is used for fastening, it can be reused any number of times unlike the conventional example using the plastic deformation. The above-mentioned lock nut bulging inner wall portion 2
If hard chrome plating or the like is applied to the outer wall portion 1e or the bolt bulging portion 1e, the durability thereof can be further improved.
For, there is no big restriction on the selection of the material,
It is also possible to select a highly flexible material suitable for the use environment, such as a heat-resistant alloy or a corrosion-resistant alloy.

Next, claim 2 will be described with reference to FIG. 4. The difference from the structure of claim 1 is as follows. First, the thick base end 1a of the bolt body 1
A thin protrusion 1i is formed between the bolt and the male screw portion 1b, so that the thin protrusion 1i is in the through-hole 3a of the body 3 to be fastened, and the thin protrusion 1i is The fitting is provided, which can promote the stability of the screwed fastening state, and can prevent the damage of the male screw portion 1b. Further, the insertion tip 1f of the thinned tip 1c is connected to the bolt bulging outer wall 1e by a tapered taper 1j. Thus, the insertion tip 1f strikes the lock nut swelling inner wall 2c. They try to prevent them from being scratched by contact. Further, in the second aspect, the fine distal end portion 2b of the lock nut 2 is made to penetrate without closing the distal end side, so that the projecting length of the bolt main body 1 from the thick base end portion 1a is small. In addition, even if the size is large, the fastening operation can be performed without any trouble. In addition, the lock nut 2 is formed by a nut portion 2A and a thin cylindrical portion 2B which is connected to the nut portion and has a smaller diameter than the nut portion 2A.
A lock nut swelling inner wall portion 2 as described above is formed on the thinned cylindrical portion 2B.
c is formed, thereby not only reducing the weight of the lock nut 2 but also easily setting the resistance based on the elastic deformation of the lock nut bulging inner wall portion 2c so as not to become excessively large. I have to.

Here, in the screw-fastening locking mechanism illustrated in FIG. 4, a bolt body 1 as a fuel element in a nuclear fuel assembly is illustrated, and a thin protrusion 1i, a bolt male screw 1b, and a thin bolt The front end portion 1c corresponds to a fuel element end plug screw portion made of a zirconium alloy, the fastened body 3 shows a tie plate made of stainless steel, and a lock nut 2 made of stainless steel is disclosed as the lock nut 2. ing.

[0015]

Since the present invention is constructed as described above, according to claim 1, the bolt bulging outer wall portion is focused on elastic deformation without using plastic deformation as in the prior art. And the lock nut bulging inner wall can be used effectively, so that the bolt body and lock nut can be used repeatedly, and the resistance to loosening can be set considerably high. Because of its simplicity, a highly reliable locking effect can be guaranteed. In addition, since it is not necessary to use a special material, it is possible to select a material suitable for the use environment such as a heat-resistant alloy, and more importantly, it is usually used when screwed or disassembled. It is possible to achieve the purpose only by the screwing operation of, and to perform a special work using a special tool, and further, it is possible to eliminate the defects of the conventional example such that the skill is required for the work, so that the screw fastening and It is easy to automate the disassembly process.

According to the second aspect of the present invention, not only the above-mentioned effect can be exerted, but also the fastening can be stabilized by the thin protrusion, and the tapered portion is formed at the insertion end of the bolt body, so that the locking can be achieved. It is possible to avoid damaging the inner wall portion of the lock nut swelling of the nut, and by connecting the lock nut with the nut portion and the thin cylindrical portion, not only can the overall size and weight be reduced, but also the lock nut It is possible to easily adjust the resistance based on the elastic deformation of the bulging inner wall to an appropriate value without unnecessarily increasing it, and by making the fine tip end of the lock nut a penetrating state. Accordingly, it is possible to realize the threaded fastening state without any trouble regardless of the length of the bolt body.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view showing a fastening state of a screw engagement loosening prevention mechanism according to a first embodiment.

2A and 2B show a bolt main body as one component member according to the same invention, wherein FIG. 2A is a front view of a main part thereof and FIG. 2B is a left side view.

3A and 3B show a lock nut as another component according to the same invention, wherein FIG. 3A is a longitudinal sectional front view and FIG. 3B is a right side view.

FIG. 4 is a partially cutaway front view showing a state before fastening, showing a threaded fastening loosening prevention mechanism according to claim 2;

FIG. 5 is a perspective view showing a state before fastening of a conventional screw-fastening loosening prevention mechanism.

FIG. 6A is a perspective view showing a fitting state between the conventional bolt body and a lock nut, and FIG. 6B is a perspective view showing a fastening state.

[Explanation of symbols]

 Reference Signs List 1 Bolt main body 1a Thick base end 1b Bolt male screw 1c Narrow tip 1d Narrow relief 1e Bolt bulging outer wall 1f Insertion tip 1g Outer wall bulge 1h Bolt receiving tip 1i Narrow protrusion 1j Taper portion 2 Lock nut 2A Nut portion 2B Thin cylindrical portion 2a Lock nut female screw portion 2b Thin tip end portion 2c Lock nut bulging inner wall portion 2d Inner wall protruding portion 2e Lock nut receiving base end face 3 Fastened body 3a Entrance

Claims (2)

[Claims] 1. A bolt body having a thinned base end portion, a bolt male screw portion, and a thinned distal end portion which are sequentially thinned from the base end side, a lock nut female screw portion and a thinned distal end portion on the base end side. And a narrowed escape portion and a bolt bulging outer wall portion are continuously provided toward the distal end side at the narrowed distal end portion of the bolt body. Forms a lock nut swelling inner wall portion, and a lock nut female screw portion of the lock nut is screwed into the above-mentioned male screw portion of the bolt protruding from a fine tip portion of the bolt body through a through hole of the fastened body. By this, the inner wall protruding portion of the lock nut bulging inner wall portion crosses over the outer wall protruding portion of the bolt bulging outer wall portion due to elastic deformation, and the base end side of the lock nut bulging inner wall portion becomes narrower of the bolt body. It is said that it can enter the escape part freely, A screw-fastening locking mechanism, wherein the bolt receiving tip surface of the thick base portion and the lock nut receiving base surface of the lock nut female screw portion are fastened to each other. 2. A bolt body having a thin and thick base end, a thin protrusion, a bolt male screw portion, and a thinned tip in order from the base end, a nut on the base end, and a connection therewith. And a lock nut having a thin tip end portion penetrating through the thin cylindrical portion in communication with the lock nut female screw portion of the nut portion. At the narrowed tip of the main body, a narrowed relief portion, a bolt bulging outer wall portion, and a tapered taper portion are continuously provided toward the distal end side, and the bolt body is opened from the thinned tip portion to the opening of the fastened body. By entering the lock nut female thread portion through the above and screwing the bolt male screw portion into the lock nut female screw portion, the outer wall outflow portion of the bolt bulging outer wall portion flows out of the inner wall of the lock nut bulging inner wall portion. Of the lock nut bulges over the inner wall part by elastic deformation. Makes it possible to freely enter the narrowed escape portion of the bolt body, and in this state, the thinned distal end portion of the bolt body advances through the tapered tapered portion from the thinned distal end opening portion, whereby the object to be fastened is formed. A screw-fastening locking mechanism, wherein the bolt receiving tip surface of the thick base portion and the lock nut receiving base surface of the lock nut female screw portion are fastened to each other.