JPH0221441B2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to studs.

(Prior Art) As shown in FIG. 5, a conventional stud bolt of this type has a stud screw 2 installed at one end, which is implanted in one member, and a nut screw 2 that passes through the other member. It has a structure in which a screw 3 is provided on the other end side, and a nut is screwed into the nut-side screw 3 of the bolt 1 and tightened, thereby fixing the other member to the one member.

However, in the stud bolt 1 having such a structure, even if the nut is strongly tightened, the threading of the stud screw 2 to the one member often loosens, especially when the one member is made of aluminum or If it is made of soft material such as synthetic resin, it has the problem of loosening easily.

Furthermore, a bolt described in Japanese Patent Application Laid-Open No. 55-10199 is known. As shown in FIG. 6, this bolt has an implant-side screw 22 at one end that is implanted in one member 21, and a nut-side screw 25 that passes through the other member 23 and onto which a nut 24 is screwed. is provided on the other end side, and the nut side screw 25
In the stud bolt that fixes the other member 23 to one member 21 by screwing and tightening the nut 24 to A flange portion 26 having a larger diameter than the side screw 22 and the nut side screw 25 is formed, and this flange portion 26 has a function of transmitting the rotational force of a tool when screwing the implant side screw 22 into one member 21. together with the nut side screw 25
A structure is adopted in which a protrusion 27 is formed which bites into the other member 23 when the nut 24 is tightened and screwed together.

(Problems to be Solved by the Invention) In the structure of the bolt described in JP-A-55-10199, as shown in FIG.
If the vertical height of the rotation receiving surface 28 of the protrusion 27 formed in the projection part 27 is low, the rotational force of the tightening tool will not be transmitted.
The tip of 7 is formed at an acute angle, and the other member 2
It must be made of a material harder than 3. However, if the hardness of the tip of the protrusion 27 is increased to such an extent that it will not be crushed during tightening, the bolt itself will become harder, but on the other hand, it will become brittle and vulnerable to fluctuations in external force after tightening, so the protrusion 27 will not collapse. However, if the hardness of the protruding part 27 is low, the tip of the protruding part 27 will be crushed and deformed, as shown in FIG. There is a problem that a gap H1 is generated between the two. Further, as shown in FIG. 7, when the protruding part 27 bites into the other member 23, the volume of the protruding part 27 that bites in turns into raised parts 29, 30.
is formed, and the flange portion 26 and the other member 23 are not in close contact with each other, creating a gap H2 between the flange portion 26 and the other member 23. Therefore, the load on the other member 23 is increased. The load bearing area of the portion 27 is extremely small, and it tends to sag due to external force, resulting in a decrease in tightening force.The amount of sagging caused by this external force is There is a problem that the amount of loosening increases several times, creating play in the direction of rotation and starting to loosen, increasing the amount of loosening due to repeated changes in external force, and finally loosening completely.

The present invention has been made in view of the above-mentioned problems, and it is possible to bring one member and the other member into close contact with each other by fastening, and after fastening, the serration part does not become sag due to the load of external force. Therefore, it is an object of the present invention to provide a stud bolt that does not loosen and can be easily and inexpensively manufactured.

[Structure of the invention]

(Means for Solving the Problems) The embedded bolt of the present invention has an embedded screw embedded in one member on one end side, passes through the other member, and has a nut side screwed into the other member. In the stud bolt, which has a screw on the other end side and fixes the other member to the one member by screwing and tightening the nut to the nut side screw, the stud side screw and the nut side screw are connected to each other. A biting part is formed on the outer periphery of the intermediate part of the screw, and the biting part is larger in diameter than the implant side screw and the nut side screw, and bites into the fitting hole formed in the other member with a diameter larger than the through hole. The device is characterized in that a serration is formed around the periphery, having a ridge diameter in the axial direction that is larger in diameter than the fitting hole, and a trough diameter in the axial direction that is smaller in diameter due to the fitting hole.

(Function) The present invention screws the implantation side screw into one member,
When the nut is inserted into the through-hole of the other member and the nut is tightened, the biting part fits into the fitting hole of the other member and the area around the biting part is tightened. The peaks of the serrations formed in the above bite into the inner wall of the fitting hole, and the curling caused by the bite of the peaks enters the troughs of the serrations, preventing them from protruding between the two members and the other member. One member and the other member are in close contact with each other, rotation of the stud bolt is prevented by the biting of the serrations in the biting part,
The implant side screws do not loosen, and after tightening, external force is applied in the axial direction, so no load is applied to the serrations, and the serrations do not become sagging due to external force loads. be.

(Embodiment) The configuration of an embodiment of the present invention will be described based on FIGS. 1 to 3.

The stud bolt 11 is made of a round bar-shaped steel material, and has a stud thread 12 formed at one end, a nut thread 13 at the other end, and a biting part 14 on the outer periphery of the intermediate part. is formed.

The implant side screw 12 and the nut side screw 13 are:
Its thread dimensions, i.e. outer diameter, effective diameter, root diameter,
The angle and pitch of the threads are the same, and both are formed by rolling.

Further, the biting portion 14 is formed on the implant side screw 12.
It has a larger diameter than the nut side screw 13, and has a polygonal shape with a serration process applied to the periphery.

Of the two members 15 and 16 that are mutually connected and fixed by this stud bolt 11, one member 15 is formed with a female threaded portion 17 that screws into the implant side screw 12, and the other member 16 is A through hole 18 is formed through which the nut side screw 13 passes, and the biting portion 1 is formed at one end of this through hole 18.
A fitting hole 19 into which 4 is fitted is formed. This fitting hole 19 has a larger diameter than the through hole 18, is smaller than the outer diameter of the axial peak portion of the serrations that round the outer periphery of the biting portion 14, and has a diameter smaller than the axial trough portion of the serration. larger than the diameter of

Next, the operation of this embodiment will be explained.

Connect the implant side screw 12 to the female threaded portion 1 of one member 15.
7, the nut side screw 13 is passed through the through hole 18 of the other member 16, and the nut 20 is screwed and tightened. As this nut 20 is tightened, the biting part 14 fits into the fitting hole 19 of the other member 16, and the peak part of the serrations forming corners around the biting part 14 bites into the inner wall of the fitting hole 19. It's crowded.
The peaks of the serrations of the biting portion 14 bite in the length direction of the peaks formed in the axial direction, so they are easy to bite, and when the peaks of the serrations collapse, they first come into contact with the inner wall of the fitting hole 19. Just by doing
Overall, there are few crushed parts, and there is little influence from crushing, and the warping of the inner wall of the fitting hole 19 due to the ridges biting into the serrations will not enter the troughs of the serrations and come out to the one member 15 side.
One member 15 and the other member 16 are closely attached to each other. Furthermore, the depth of the bite of the peaks of the serrations in the biting portion 14 is 1/1/1 of the height of the peaks of the serrations.
Approximately 4 to 1/3 has sufficient anti-loosening action,
There is no need to dig into the valleys of the serrations of the biting portion 19, and the fastening workability is improved.

Furthermore, after tightening, the external force is only applied in the axial direction, so no load is applied to the serration peaks.
The rotation of the bolt 11 does not occur in the serration section due to the load of external force, and the rotation of the bolt 11 does not occur in the biting section 1.
This is prevented by the biting of No. 4, and the tightening of the implant-side screw 12 does not loosen.

Since the thread dimensions of the implant side screw 12 and the nut side screw 13 are the same, both can be rolled with a common rolling tool, and serration processing can also be performed by rolling. The formation of the implant side screw 12 and the nut side screw 13 and the formation of the biting part 14 by serration processing can be done at the same time, making it easy to manufacture and inexpensive.

Note that the outer peripheral area of the biting portion 14 is the same as that of the female threaded portion 17.
It is widened when the material of one member 15 forming the is soft, and it is also widened when the tightening force for tightening the other member 16 is large.

〔Effect of the invention〕

According to the present invention, one member and the other member are brought into close contact with each other, and the two members can be reliably connected and fixed without loosening, and even if the two members are soft members such as aluminum or synthetic resin, Moreover, the peaks of the serrations at the biting part dig into the fitting hole along the axial length direction, so the peaks of the serrations easily bite into the fitting hole, preventing biting. In addition to being easy, there is almost no collapse of the serrations, the biting is reliable, and fastening workability is good.Furthermore, since the external force is received in the axial direction after tightening, there is no load on the peaks of the serrations at the biting part, and the external force is reduced. The initial loosening force is maintained and the serrations do not set due to the load, and the serrations do not loosen due to the load. Furthermore, the serrations in the biting part easily bite, so it is especially suitable for materials such as carbon steel or alloy steel. Ordinary quenching and tempering treatments are sufficient, and hardness treatments such as carburizing or induction hardening are not required.

[Brief explanation of drawings]

Fig. 1 is a front view of a stud bolt showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional front view showing a state in which the stud bolt is tightened, and Fig. 3 is a front view of a member fixed by the stud bolt. A partially longitudinal front view, FIG. 4 is a sectional view showing the biting state of the biting portion, FIG. 5 is a front view showing a conventional stud bolt, and FIGS. 6 and 7.
The figure is a partial sectional view showing another conventional stud bolt in a fastened state. 11... Stud bolt, 12... Stud side screw, 1
3... Nut side screw, 14... Biting part, 15...
...one member, 16...other member, 18...through hole, 19...fitting hole, 20...nut.

Claims (1)

[Scope of Claims] 1. An implant-side screw to be implanted in one member is provided on one end side, and a nut-side screw that penetrates the other member and into which a nut is screwed is provided on the other end side, In a stud bolt that fixes the other member to one member by screwing and tightening the nut onto the nut side screw, the stud side A biting part is formed that bites into a fitting hole that is larger in diameter than the screw and the nut side screw and larger in diameter than the through hole in the other member, and a biting part is formed around the biting part that is larger in diameter than the fitting hole. A stud bolt characterized in that a serration is formed having a peak diameter in the axial direction and a valley diameter in the axial direction that is smaller than the fitting hole. 2. The stud according to claim 1, wherein the stud side screw and the nut side screw are each formed by rolling.