JP3178205U - Bolt fall-off prevention structure - Google Patents

Abstract

To provide a bolt drop-off prevention structure capable of reliably preventing a bolt from dropping off by an easy operation without requiring separate parts.
A split groove 4 is formed along the shaft core on the tip side of a shaft portion 3 on which a male screw of the bolt 1 is formed, and objects to be fastened 11 and 12 are fastened by the bolt 1, and then the bolt The tip end side of the shaft portion 3 is expanded by pushing open the split groove 4 with a punch or the like.
[Selection] Figure 3

Description

  The present invention relates to a bolt fall-off prevention structure that can prevent the bolt from coming off without being loosened by vibration or the like.

A general method of using a conventional bolt is shown in FIGS.
In FIG. 5, through-holes 51a and through-holes 52a formed with internal threads are formed in the members 51 and 52 to be fastened, respectively, and bolts 53 are inserted into the through-holes 51a and 52a. The members 51, 52 are fastened by screwing the male screw formed on the bolt 53 into the female screw of the through hole 52 a formed on the member 52. Further, in FIG. 6, through holes 51a and 52a are formed in the members 51 and 52 to be fastened, respectively, and a bolt 53 is inserted into the through holes 51a and 52a, and the male screw formed on the bolt 53 is The members 51 and 52 are fastened by screwing into the female screw of the nut 54.
The bolt 53 has a hexagonal columnar head portion 53a having a shape suitable for tightening with a tool such as a spanner or a hexagon wrench, and a shaft portion 53b having a male screw formed on the outer peripheral surface thereof.

  By the way, as shown in FIGS. 5 and 6, even if the members 51 and 52 are fastened by the bolt 53, when the vibrations are applied for a long period of time in an environment where the vibration is applied, the bolts loosen due to the vibrations, and the bolt 53 becomes a member. The through holes 51a and 52a of the 51 and 52 sometimes dropped out.

Therefore, as shown in FIG. 7, a bolt is proposed in which a through hole 53c is formed in the radial direction near the tip of a bolt shaft 53b, and a split pin 55 is inserted into the through hole 53c.
In such a bolt, after the object to be fastened is fastened by the bolt, the split pin 55 is inserted into the through hole 53c, and both ends thereof protrude outward from the outer peripheral surface of the bolt shaft portion 53b. Even if the bolt is loosened due to the above, the split pin 55 is brought into contact with the plate surface of the member 52 (or the end surface of the nut 54 when the bolt 53 is screwed to the nut 54) and locked. Therefore, the bolt 53 is prevented from falling off.

  However, since the above-described bolt drop-off preventing structure requires the split pin 55 as an accessory, the cost is high, and the operation of inserting the split pin 55 into the through hole 53c formed in the bolt 53 is performed. It took time and was not easy to carry out.

  The present invention has been made in view of the drawbacks of the conventional bolt drop-off prevention structure described above, and its purpose is to reliably prevent bolt drop-off by an easy operation without requiring separate parts. An object of the present invention is to provide a structure for preventing the bolt from falling off.

  In order to achieve the above-described object, the present invention forms a hole or a split groove along the shaft core on the tip side of the shaft portion on which the male screw of the bolt is formed, and fastens an object to be fastened with the bolt. A bolt drop-off prevention structure is provided, in which the tip side of the shaft portion of the bolt is expanded by pushing open the hole or the split groove.

  According to the bolt fall-off prevention structure of the present invention described above, after fastening an object to be fastened, the front end side of the shaft portion of the bolt is expanded by pushing open a hole or a split groove with a punch or the like. Since the drop-off prevention is achieved, no other parts other than bolts are required, and the operation is easy. Further, since the hole or split groove is simply formed along the shaft core on the tip end side of the shaft portion where the male screw of the bolt is formed, the processing is easy and inexpensive.

It is the figure of the volt | bolt shown as an example which implement | achieves the fall-off prevention structure of the volt | bolt concerning this invention, Comprising: (a) is a top view, (b) is a side view. It is the side view which showed the state which fastened the to-be-fastened object using the volt | bolt shown in FIG. It is the side view which showed embodiment which expanded the front end side of the axial part of the volt | bolt of the state of FIG. 2 using a punch, and implement | achieved the fall-off prevention structure of the volt | bolt which concerns on this invention. It is the side view which showed other embodiment which implement | achieved the drop-off prevention structure of the bolt concerning this invention. It is the side view which showed an example of the use condition of the conventional volt | bolt. It is the side view which showed the other example of the use condition of the conventional volt | bolt. It is the side view which showed the state which implement | achieved the conventional bolt drop-off prevention structure.

  Hereinafter, embodiments of the bolt drop-off preventing structure according to the present invention will be described in detail with reference to the drawings.

An example of a bolt that realizes the bolt fall-off prevention structure according to the present invention is shown in FIG.
The bolt 1 shown in FIG. 1 has a head portion 2 and a shaft portion 3. 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 has a cylindrical shape having a smaller diameter than the head portion 2, and a male screw is formed on the outer peripheral surface thereof. The male screw is not necessarily formed over the entire length of the shaft portion 3.

  A split groove 4 is formed on the tip side of the shaft portion 3 along the axis. The split groove 4 is formed so that the distal end side of the shaft portion 3 is easily expanded and deformed. In the illustrated bolt 1, the split groove 4 is composed of a cylindrical hole 4a formed at the center and a slit 4b having a width narrower than the diameter of the cylindrical hole 4a. The cylindrical hole portion 4a formed in the above serves as a guide portion for a tool such as a punch.

When the bolt 1 is 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. 2, through-holes 11 a and 12 a are formed in the members 11 and 12 to be fastened, respectively, and the bolt 1 is inserted into the through-holes 11 a and 12 a to form the bolt 1. The members 11 and 12 are fastened by screwing the male screw with the female screw of the nut 13.

After fastening the objects to be fastened 11 and 12 with the bolt 1, as shown in FIG. 3, the front end side of the shaft portion 3 of the protruding bolt 1 is inserted into the split groove 4 formed on the front end side with a punch or the like. The tool P is pushed open and expanded.
The expanding operation on the front end side of the shaft portion 3 of the bolt 1 can be easily performed by the presence of the split groove 4. Further, as in the case of the bolt shown in FIG. 1, in the case where the split groove 4 is composed of a cylindrical hole portion 4a and a slit portion 4b, the cylindrical hole portion 4a formed at the center has a punch. It acts as a guide part of the tool P such as, and the expansion is performed uniformly.

By expanding the front end side of the shaft portion 3 of the bolt 1, the looseness of the nut 13 is constrained, and the bolt 1 is not loosened even if vibration is applied for a long time, and the bolt 1 is prevented from falling off. The
Moreover, since the front end side of the shaft portion 3 of the bolt 1 is simply bent and expanded at the portion of the split groove 4, when removing the bolt 1, a tool such as a spanner or a hexagon wrench is used. If the bolt 1 or the nut 13 is rotated in the removal direction by using it, the expanded portion is reduced with the rotation, and the bolt can be easily removed.

  FIG. 4 is a side view showing another embodiment that realizes the bolt drop-off preventing structure according to the present invention. In this embodiment, the through-hole 21a and the through-hole 22a in which the internal thread was formed are formed in the members 21 and 22 to be fastened respectively, and the bolt 1 is inserted into the through-holes 21a and 22a. The members 21 and 22 are fastened by screwing the male screw formed on the bolt 1 into the female screw of the through hole 22a formed on the member 22.

  And after fastening a to-be-fastened thing, as shown in FIG. 4, the front end side of the axial part 3 of the volt | bolt 1 which protruded is used for the split groove 4 formed in this front end side, using tools P, such as a punch. The structure for preventing the bolt from falling off according to the present invention is realized by pushing and expanding.

  The embodiment of the bolt drop-off prevention structure according to the present invention has been described above. However, the present invention is not limited to the embodiment described above, and the technology of the present invention described in the claims of the utility model registration. It goes without saying that various modifications and changes can be made within the scope of the technical idea.

  For example, in the above embodiment, the description has been given of the case where the split groove 4 is formed along the shaft core on the distal end side of the shaft portion 3 of the bolt 1, but it is also possible to simply form a cylindrical hole or the like. . In the above 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.

  The bolt fall-off prevention structure according to the present invention is a bolt used for fastening parts used in an environment where vibration is applied, such as automobiles, ships, and parts of household electrical appliances such as washing machines equipped with motors. It can be widely used for bolts used for fastening.

DESCRIPTION OF SYMBOLS 1 Bolt 2 Head 3 Shaft part 4 Split groove 4a Cylindrical hole part 4b Slit part 11, 12 Member to be fastened 11a, 12a Through-hole 13 Nut 21, 22 Member to be fastened 21a Through-hole 22a Female on inner peripheral surface Screw-shaped through hole P Punch and other tools

Claims (2)

  A hole or a split groove is formed along the shaft core on the front end side of the shaft portion on which the male screw of the bolt is formed, and after fastening an object to be fastened with the bolt, the front end side of the shaft portion of the bolt is A structure for preventing a bolt from falling off, wherein the structure is expanded by pushing open a hole or a split groove.   2. The bolt according to claim 1, wherein the split groove includes a cylindrical hole portion formed in the center and a slit portion having a width narrower than a diameter of the cylindrical hole portion. Fall-off prevention structure.

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