JP2007270889A - bolt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To screw a bolt in a hole of an object to be fastened by using a fastening tool so as to fix the bolt to the object to be fastened. <P>SOLUTION: The bolt 1 is provided with a projection part 7 projected from an inclined face 6b of a ridge 6 at a terminal portion 6a on a head part 8 side of the ridge 6 of a shaft part 5. The bolt of this constitution is screwed in a female screw 3b formed in the hole of the object 3 to be fastened, the projection part 7 disposed to the terminal portion 6a of the ridge 6 is seized and fixed (friction-welded) to a screw groove of the female screw 3b. Therefore, the bolt 1 is fixed to the object 3 to be fastened in such a state that the shaft part 5 is inserted into the hole formed in the object 3 to be fastened. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a bolt that is fixed to a fastened object in advance, and relates to a bolt that is fixed to a fastened object without using a welding machine or a press.

  One of the methods for fastening the fastening object to the article to be fastened is a fastening method using bolts and nuts. The procedure for this fastening operation is as follows. First, the holes through which the bolt shafts pass are provided in the fastened object and the fastened object, respectively, and then the fastened object and the fastened object are overlapped so that the holes of each other coincide with each other. Bolts are passed through the holes. And fastening with a to-be-fastened thing and a fastening thing is completed by fastening | tightening a nut from the front end side of a volt | bolt.

  However, when tightening the nut, there was a problem that the bolt could rotate together and the nut could not be tightened. As a method of preventing co-rotation, there is a method of tightening a nut while fixing a bolt head with a tightening tool such as a wrench. However, in the case of a fastener having a size in which a bolt cannot be tightened by one worker alone, there is a problem that two workers are required and work efficiency is deteriorated.

In order to solve this co-rotation and deterioration of work efficiency, a method of fixing a bolt to an object to be fastened in advance has been used. There are mainly three methods for fixing the bolt to the object to be fastened. The first is a method of welding and fixing the back side of the bolt head and the object to be fastened. The second is a method in which a bolt having a shape in which a part of the shaft portion of the bolt is caught in the hole is press-fitted into the hole of the object to be fastened. Third, as shown in Patent Document 1, a flange is provided at the peripheral edge of the hole of the fastened object, and when the bolt is press-fitted into the fastened object, the flange portion is deformed and the constriction on the back side of the head of the bolt It is a method of biting into the part and fixing the bolt.
JP 2003-90317 A

However, a welding machine is required to perform welding, and a press machine is required to perform press-fitting and caulking, so it was necessary to provide an excessive amount of equipment.
This invention is made | formed in view of the said situation, The objective is providing the volt | bolt which can be fixed to a to-be-fastened object, without using installations, such as a welding machine and a press machine.

  The bolts according to claims 1 and 2 are characterized in that, in a bolt in which a thread is formed on the shaft portion, a projecting portion protruding from the thread is formed at a terminal portion of the thread. In this bolt, the thread of the shaft is screwed into the female screw formed in the hole of the fastened object, so that the projecting portion of the terminal portion of the screw thread slides on the inner surface of the thread groove of the female screw. The shaft portion is fixed to the object to be fastened in contact with the shaft part through a hole formed in the object to be fastened.

  The bolt according to claim 3 is characterized in that the screw thread of the shaft portion is constituted by a self-tapping screw. This bolt forms an internal thread that is screwed onto the inner surface of the hole of the object to be fastened with no gap, so that the protrusion provided at the end portion of the thread is stronger on the inner surface of the thread groove of the internal thread. Engage and engage.

  According to a fourth aspect of the present invention, the bolt has a head at the shaft portion, and contacts a member formed with an internal thread on which the protrusion slides on the back side of the head and rotates in a direction opposite to the screwing direction. An anti-rotation protrusion for stopping is formed. In this bolt, when the end portion of the screw thread is screwed into the female screw, the protrusion bites into the member, or even if it does not bite into the member, it stops to rotate in the direction opposite to the screwing direction. Moreover, even when the fixing strength of the bolt to the member is low, it is possible to prevent the rotation of the bolt when tightening the nut as much as possible.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a fastened object 3 and a fastened object 4 fastened by a bolt 1 and a nut 2 of the present invention, FIG. 2 is a perspective view showing an external appearance of the bolt 1, and FIG. It is. As shown in FIGS. 1 to 3, a thread 6 is formed on the shaft portion 5 of the bolt 1. The shaft part 5 has a self-tapping function part 5a having a substantially truncated cone shape on the distal end side, and a straight part 5b on the proximal end side.

The external shape of the thread 6 of the self-tapping function portion 5a is substantially triangular as shown in FIG. 4A, and further, the external shape of the thread 6 gradually decreases toward the tip of the bolt 1. On the other hand, the outer shape of the thread 6 of the straight portion 5b is circular as shown in FIG.
Both slopes 6b of the thread 6 of the end portion 6a of the thread 6 of the straight portion 5b, for example, both slopes 6b of the thread 6 for two threads corresponding to the axial length longer than the plate thickness of the article 3 to be fastened. As shown in FIGS. 3 and 5, a plurality of protrusions 7 that protrude substantially perpendicular to the lead angle are provided. The protrusion 7 is formed by crushing the top portion of the thread 6 and protruding from the inclined surface 6b.

A head 8 is provided at the base end of the shaft portion 5 of the bolt 1. On the back side 8a of the head 8 where the shaft portion 5 is provided, for example, six anti-rotation protrusions 9 are arranged on the outer peripheral side of the shaft portion 5 at intervals equal to the circumferential direction. The axial height L of each of the anti-rotation projections 9 is such that the anti-rotation projection 9 bites into the article to be fastened 3 when the bolt 1 is fastened to the article to be fastened 3 as shown in FIG.
As shown in FIG. 6, a hexalobular hole 8 c is formed on the front side 8 b of the head 8.

Next, the operation when the bolt 1 is fixed to the fastened object 3 will be described with reference to FIG.
First, a driver bit for a hexalobular hole is attached to a power driver such as an electric driver or an air driver (not shown), and further, the hexalobular hole 8c of the head 8 of the bolt 1 is engaged with this driver bit. And the front-end | tip of the volt | bolt 1 is inserted in the hole 3a provided in the to-be-fastened object 3. FIG.

  Next, when the driver bit is rotated so that the bolt 1 is screwed, the bolt 1 is screwed from one side of the article 3 to be fastened to the other side, and the top of the thread 6 is in the hole 3a of the article 3 to be fastened. Contact the inner surface. When the bolt 1 is further screwed, as shown in FIG. 7A, the top of the thread 6 of the self-tapping mechanism portion 5a shaves the inner surface of the hole 3a of the fastened object 3, and the fastened object 3 A female screw 3b is formed on the inner surface of the hole 3a.

  Then, when the two threads 6 of the end portion 6a of the thread 6 of the straight portion 5b enter the inside of the hole 3a of the fastened object 3 while rotating, as shown in FIG. The protrusion 7 formed on the screw thread 6 of the bolt 1 is pushed into the screw groove of the female screw 3b of the hole 3a and moves on the screw groove of the female screw 3b while pressing strongly against the screw groove of the female screw 3b. At this time, the protrusion 7 generates frictional heat by sliding with the thread groove of the female screw 3b.

  Further, as shown in FIG. 7C, when the bolt 1 is screwed into the female screw 3b up to the terminal portion 6a of the thread 6 of the straight portion 5b, the projecting portion 7 that is strongly pressed against the thread groove of the female screw 3b is obtained. The generated frictional heat burns into the thread groove of the internal thread 3b (a kind of friction welding) and is firmly coupled, and the anti-rotation protrusion 9 provided on the back side 8a of the head 8 of the bolt 1 is attached to the object 3 to be fastened. Fix the bolt 1 in a state where the bolt 1 is stopped.

  On the other hand, a hole 4a that is slightly larger than the shaft portion 5 of the bolt 1 is formed in the fastener 4, and the fastener 4 is overlapped so that the tip of the bolt 1 is inserted into the hole 4a. Then, by tightening the nut 2 with a nut 2 tightening tool (not shown), the fastened object 3 and the fastened object 4 are fastened by the bolt 1 and the nut 2.

In the above embodiment, the following effects can be obtained.
By providing the protrusion 7 on the screw thread 6, the protrusion 7 is friction welded to the thread groove of the female screw 3 b of the article 3 to be fastened, whereby the bolt 1 can be fixed to the article 3 to be fastened. Therefore, the bolt 1 can be fixed to the article 3 to be fastened by using a power driver such as an electric driver or an air driver for screwing the bolt 1 and a driver bit without using a welding machine or a press machine. . Therefore, in the assembly line, the bolt 1 can be fixed to the article 3 to be fastened in the previous step of tightening the nut 2.

  Since the self-tapping function portion 5a of the shaft portion 5 of the bolt 1 is provided, even if the female screw 3b is not provided in advance in the fastened object 3, the inner surface of the hole 3a of the fastened object 3 is caused by screwing of the bolt 1. An internal thread 3b can be formed. Further, since the screw thread 6 of the bolt 1 can be in contact with the formed female screw 3b without a gap, the protrusion 7 provided on the bolt 1 can be strongly bitten and engaged with the screw groove of the female screw 3b ( It becomes easy to seize).

By providing the non-rotating projection 9 on the back side 8a of the head 8, when the bolt 1 is screwed into the female screw 3b up to the end portion 6a of the thread 6 of the straight portion 5b, the non-rotating projection 9 is attached to the article 3 to be fastened. Therefore, even if the fixing strength of the bolt 1 to the fastened object 3 is low, the rotation of the bolt 1 when the nut 2 is tightened can be prevented as much as possible. .
Since the engaging portion of the tightening tool formed on the front side 8b of the head 8 is the hexalobular hole 8c that can efficiently transmit the torque of the tightening tool, the head 8 of the bolt 1 can be made thin. .

The above invention is not limited to the above embodiment, and can be modified or expanded as follows.
In the bolt 1 of the above embodiment, the tip of the bolt 1 is the self-tapping function part 5a in order to eliminate the need to form the female screw 3b in the hole 3a of the article 3 to be fastened. The self-tapping function part 5a may not be provided as long as the female thread 3b that can be screwed with the thread 6 of the one straight part 5b is formed.
In the said embodiment, although the protrusion 7 was provided in the screw thread 6 for two threads, it is not restricted to this. For example, when the article to be fastened 3 is thick, the number of threads 6 that provide the protrusion 7 may be increased. Moreover, you may provide the protrusion 7 in the range shorter than the axial direction length equivalent to the plate | board thickness of the to-be-fastened thing 3, for example, only 1 mountain. The protrusion 7 may be provided only on the one slope 6b instead of the both slopes 6b, and since the protrusion 7 only has to protrude from the screw thread 6, the protruding direction may be arbitrary. Furthermore, the number of the protrusions 7 may be one, and it may extend long along the spiral of the thread 6.

  The protrusion 7 is not limited to one that is seized and fixed (friction welded) to the thread groove of the female screw 3b of the article 3 to be fastened, and the bolt 1 is fastened by the press-fitting of the protrusion 7 into the screw groove of the female screw 3b. As long as it is fixed to the surface.

In the bolt 1 of the above embodiment, when the bolt 1 is attached to the article 3 to be fastened, the rotation preventing projection 9 is arranged in an annular shape on the back side 8a of the head 8 in order to stop the rotation opposite to the screwing direction. However, as long as there is an action to stop the rotation opposite to the screwing direction, the number and arrangement location of the rotation-preventing protrusions 9 provided on the back side 8a of the head 8 may be arbitrary.
The bolt 1 of the above embodiment is provided with the hexalobular hole 8c on the front side 8b of the head 8 for tightening the bolt 1, but can be tightened with an arbitrary driver bit or a tightening tool instead of the hexalobular hole 8c. May be provided on the head 8.

Sectional drawing which shows fixation of the to-be-fastened object and fastening object by the volt | bolt and nut in this invention Bolt appearance perspective view Bolt front view (A) is sectional drawing which follows the AA line of FIG. 3, (b) is sectional drawing which follows the BB line of FIG. Enlarged cross-sectional view of the end of the bolt thread Bolt top view (A)-(c) is sectional drawing which shows operation | movement description of the screwing to the fastener of a volt | bolt.

Explanation of symbols

  In the drawings, 1 is a bolt, 2 is a nut, 3 is an object to be fastened, 3b is a female screw, 4 is a fastener, 5 is a shaft portion, 5a is a self-tapping function portion (self-tapping screw), 6 is a screw thread, and 6a is An end portion, 6b is a slope, 7 is a protrusion, 8 is a head, 8a is a back side, and 9 is a detent projection.

Claims (4)

In bolts with threads on the shaft,
A bolt formed by forming a protruding portion protruding from the thread at the terminal portion of the thread. A bolt for fixing a fastening object to a fastened object by screwing a nut to a shaft part on which a screw thread is formed, and the shaft part is passed through a hole formed in the fastened object. In the bolt fixed to the fastened object,
A protrusion projecting from the thread is formed at the terminal portion of the thread, and the thread of the shaft is screwed into the female thread formed in the hole of the object to be fastened. The bolt characterized in that the projection of the portion is in sliding contact with the inner surface of the thread groove of the female screw and the shaft is passed through a hole formed in the object to be fastened. .   The bolt according to claim 1 or 2, wherein the screw thread of the shaft portion is constituted by a self-tapping screw.   The shaft portion has a head, and a detent protrusion is formed on the back side of the head to stop the rotation in the direction opposite to the screwing direction in contact with a member formed with a female screw with which the protrusion slides. The bolt according to any one of claims 1 to 3, wherein the bolt is provided.

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