JPH11182521A - Screw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To screw a male screw into a female screw without causing a cut into the female screw. SOLUTION: A spherical guide part 16 is provided at the tip part of a screw body 12 through a constricted part 15. The diameter of the constructed part 15 is determined to be not larger than the root diameter of a male screw 11, and the diameter of the guide part 16 is determined to be larger than the inside diameter of a female screw 18 and larger than the root diameter of the male screw 11. Even when the guide part 16 is inserted into a screw hole 17 with the screw body 12 tilted considerably largely, the guide part 16 can be smoothly inserted into the screw hole 17 without being caught by the screw thread of the female screw 18 since the guide part 16 is spherical. Further, since the diameter of the guide part 16 is determined to be larger than the root diameter of the male screw 11 and not larger than the inside diameter of the female screw 18, an accuracy of alignment (concentricity) of the guide part 16 with the screw hole 17 is high, and thus the screw body 12 can be smoothly screwed into the female screw 18 while the male screw 11 is positively prevented from cutting into the female screw 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw provided with a guide for guiding screwing to a female screw at a distal end.

[0002]

When a screw is screwed into a screw hole, if the screw is inclined with respect to the screw hole, the male screw bites into the female screw and cannot be further screwed, or the screw thread is damaged. Sometimes. In order to prevent this, as an example of a conventional guide screw, there is one having a configuration as shown in FIG.

The guide screw shown in FIG. 7 has a structure in which a bar-shaped guide portion 3 having a diameter smaller than the diameter of the root of the male screw 2 is provided at the tip of the screw main body 1. When the guide portion 3 is inserted into the screw hole 5 to be screwed into the female screw 4, the guide portion 3 is automatically adjusted so as to be guided by the tip of the thread of the female screw 4 so as to be concentric with the screw hole 5. 2 can be smoothly screwed into the female screw 4.

In order to insert the screw main body 1 into the screw hole 5 depending on the position where the screw hole 5 is formed, the screw main body 1 must be tilted as shown in FIG. It may not be possible. However, in the conventional guide portion 3, since the peripheral portion of the distal end portion is angular, the distal end corner portion C hits the thread of the female screw 4, and the guide portion 3 can no longer be inserted into the screw hole 5. State occurs. If this happens,
The guide portion 3 of the screw body 1 must be pulled out from the screw hole 5 and inserted again while being careful not to tilt the screw body 1 as much as possible.
Further, since the diameter of the guide portion 3 is smaller than the diameter of the root of the male screw 4, a considerable gap is formed between the guide portion 3 and the female screw 4, and the alignment accuracy of the guide portion 3 is deteriorated. In some cases, the male screw 2 may bite the female screw 4. Such a situation must be severely avoided for an assembly plant that tightens a large number of screws to complete a product.

The present invention has been made in view of the above circumstances, and has as its object to impair the centering action even when the screw body is screwed into the screw hole in a state of being largely inclined. An object of the present invention is to provide a screw capable of precisely correcting a screw main body to be concentric with a screw hole and screwing a male screw to a female screw.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a screw body having a male screw which is screwed into a female screw, and a valley of the male screw provided at the tip of the screw body. A constricted portion having a diameter dimension equal to or less than the diameter of the female thread, and a guide portion provided continuously to the tip of the constricted portion and having a diameter dimension equal to or less than the inner diameter of the female screw and equal to or greater than the diameter of the root of the male screw. At least the peripheral portions of both end portions in the axial direction of the guide portion are formed in a circular arc shape.

According to this configuration, at least the peripheral portion of the distal end portion of the guide portion has an arcuate shape, so that the guide portion can be held by the thread of the female screw even if the screw body is considerably inclined. Without this, the guide part can be smoothly inserted into the screw hole. In addition, since the diameter of the guide is determined to be greater than the diameter of the root of the male screw and less than the inner diameter of the female screw, the alignment accuracy (concentricity) of the guide with respect to the screw hole is high, and the occurrence of the situation where the male screw bites into the female screw may occur. The screw main body can be smoothly screwed into the female screw while preventing it more reliably.

According to the present invention, the guide portion has a hemispherical shape having a diameter equal to the diameter of the guide portion at both ends in the axial direction, and a narrow portion having the same diameter as the guide portion. It can be formed in a spherical shape having a diameter dimension equivalent to the dimension. With this configuration, even if the screw body is further inclined with respect to the screw hole, the guide portion can be smoothly inserted into the screw hole without being supported by the thread of the female screw.

In this case, the spherical surface on the constricted portion side of the guide portion is formed to be a spherical surface having the same center as the semispherical surface so as to form a spherical surface continuous with the hemispherical surface on the distal end side of the guide portion. Is preferred. With this configuration, even if the inclination of the screw main body with respect to the female screw is further increased, the guide portion can be inserted into the screw hole, and the centering effect of the guide portion can be exhibited.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 3 shows the whole screw. In the figure, a head 13 is formed at one end of a screw main body 12 on which a male screw 11 is formed. The head 13 has a slot or a cross hole for engaging a tool such as a screwdriver. Etc. are formed.
In addition, a washer 14 is attached in advance to the lower portion of the neck of the screw body 12.

A guide 16 is provided at the distal end of the screw body 12 via a constricted portion 15. The diameter A of the constricted portion 15 is set to be equal to or less than the diameter d1 of the valley of the male screw 11 shown in FIG. 4, and is equal to the diameter d1 of the valley in this embodiment. The diameter of the female screw 18 of the mating screw hole 17 is set to be equal to or less than the inner diameter D1 and equal to or greater than the diameter d1 of the valley of the male screw 11.

The distal end of the guide portion 16 is formed in a hemispherical shape having the same diameter as the diameter B of the guide portion 16, and the constricted portion 15 is similarly formed with a spherical surface having the same diameter as the diameter B of the guide portion 16. It is formed in a shape. In this embodiment, the constricted portion 1
The spherical surface b1 on the side of the constricted portion 15 is such that the spherical surface b1 on the fifth side forms a continuous spherical surface with the semispherical surface b2 on the tip side, in other words, so that there is no equal diameter portion between the two spherical surfaces b1 and b2. O is set at a point which coincides with that of the hemisphere b2 on the tip side.

Next, the operation of the above configuration will be described. To screw the screw body 12 into the female screw 18, a screwdriver (not shown) is applied to a slot or a cross hole of the head 13, and the guide 16 is inserted into the screw hole 17. At this time, since the distal end side of the guide portion 16 is formed in a hemispherical surface b2, even if the screw main body 12 is inserted into the screw hole 17 in a state of being largely inclined, the guide portion 16 is kept at the distal end of the thread of the female screw 18. It is guided to the back of the screw hole 17 by sliding the part. Therefore, there is no problem that the guide portion 16 is supported by the thread of the female screw 18 and it is difficult to insert the guide portion 16 into the screw hole 17 any more.

The root of the guide portion 16 is formed as a constricted portion 15 having a diameter d1 or less (equivalent in this embodiment) of the root of the external thread, and the entire guide portion 16 is formed as a spherical surface. As shown in FIG. 1, even if the screw main body 12 is inserted into the screw hole 17 in a state of being considerably inclined, the end of the screw hole 17 enters the constricted portion 15. Conversely, even if the screw main body 12 is considerably inclined, the guide portion 16 can be inserted into the screw hole 17, and the screw main body 12 is considerably inclined due to the position of the screw hole 17. Even in an environment where
The guide portion 16 can be inserted into the screw hole 17.

The guide portion 16 inserted into the screw hole 17 as described above is thereafter gradually inserted deeper into the screw hole 17 while sliding the spherical surfaces b1 and b2 against the threads of the female screw 18. Go. When the distal end of the female screw 18 (open end of the screw hole 17) is inserted into the distal end of the male screw 11 until the distal end of the female screw 18 is even locally contacted, the head 13 is pressed by the pushing force received from the driver in this state. As shown in FIG. 2, the screw body 12 stands up with respect to the screw hole 17 and is concentric with the screw hole 17, so that the entire tip of the male screw 11 hits the entire tip of the female screw 18. . At this time, since the diameter B of the guide 16 is set to be equal to or smaller than the inner diameter D1 of the female screw 18 and equal to or larger than the diameter d1 of the valley of the male screw 11, the concentricity between the guide 16 and the screw hole 17 is increased. Then, as described above, screw hole 1
When the concentricity of the screw main body 12 with respect to 7 is ensured, if the driver is turned, the male screw 11 is smoothly screwed into the female screw 18 without biting.

As described above, according to the present embodiment, the screw body 1
2 can be inserted into the screw hole 17 at an angle.
Can be screwed smoothly without biting into the female screw 18. For this reason, even if there are many screw tightening points in a mass production factory, screw tightening work can be performed smoothly,
Productivity is improved.

Further, the base of the guide portion 16 is
And the entire guide portion 16 is formed as a single spherical surface, so that the guide portion 16 can be inserted into the screw hole 17 even if the screw body 12 is tilted considerably, and its self-centering action can be reduced. Male screw 1
1 can be smoothly screwed into the female screw 18.

FIG. 5 shows another embodiment of the present invention.
The difference from the above embodiment is that the length of the guide portion 16 is slightly increased, and the spherical surface b1 on the constricted portion 15 side and the hemispherical surface b2 on the distal end side.
Is provided with the equal-diameter portion 19. As described above, when the equal diameter portion 19 is provided in the middle of the guide portion 16, the self-centering function by the equal diameter portion 19 is enhanced.

FIG. 6 shows still another embodiment of the present invention, in which only the both ends in the axial direction of the guide portion 16, that is, the periphery of the end on the side of the constricted portion 15 and the periphery of the distal end side. Are formed on the arcuate surfaces D1 and D2. In this case, in particular, the diameter of the arc surface D2 on the tip side is set to a size that does not catch on the thread of the female screw 18. The present invention is not limited to the embodiment described above and shown in the drawings. For example, the diameter of the constricted portion 15 is
The diameter may be smaller than the diameter of the first valley, and the screw head may be a hexagonal screw head.

[0020]

As described above, according to the present invention, the following effects can be obtained. According to the first aspect of the present invention, the guide portion can be smoothly inserted into the screw hole even in a state where the screw main body is considerably inclined.
Since the diameter of the guide part is set to be equal to or larger than the inner diameter of the female screw and equal to or smaller than the outer diameter of the male screw, the screw body can be aligned with the screw hole with higher concentricity, and the male screw will bite into the female screw And can be screwed smoothly.

According to the second aspect of the present invention, of the two axial sides of the guide portion, the distal end is formed in a hemispherical shape having a diameter equal to the diameter of the guide, and the constricted portion is similarly formed in the guide. The guide part is smoothly inserted into the screw hole without being supported by the thread of the female screw even if the screw body is further inclined to the screw hole because it is formed in a spherical shape with the same diameter as the diameter of the screw hole. Can be. According to the third aspect of the present invention, since the entire guide portion is formed as a single spherical surface, even in a state where the screw main body is further inclined,
The guide portion can be smoothly inserted into the screw hole.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a cross-sectional view in a state where a guide portion is inserted into a screw hole.

FIG. 2 is a sectional view showing a state where the screw main body is adjusted so as to be concentric with the screw hole.

FIG. 3 is a side view showing the entire screw.

FIG. 4 is a sectional view showing a female screw and a male screw in a screwed state for explaining an outer diameter dimension of a guide portion;

FIG. 5 is a side view of a main part showing another embodiment of the present invention.

FIG. 6 is a view corresponding to FIG. 5, showing still another embodiment of the present invention.

FIG. 7 is a diagram corresponding to FIG. 1 showing a conventional example.

[Explanation of symbols]

In the figure, 11 is a male screw, 12 is a screw body, 15 is a constricted portion, 16 is a guide portion, 17 is a screw hole, and 18 is a female screw.

Claims (3)

[Claims] 1. A screw body having a male screw to be screwed into a female screw, a constricted part provided at a tip end of the screw main body and having a diameter equal to or less than a diameter of a valley of the male screw; A guide portion provided continuously at the tip end and having a diameter smaller than the inner diameter of the female screw and equal to or larger than the diameter of the valley of the male screw, wherein at least peripheral portions of both ends in the axial direction of the guide portion are arc-shaped. A screw characterized by being formed in. 2. The guide part has a hemispherical surface with a diameter equal to the diameter of the guide part at both ends in the axial direction, and a narrow part with the same diameter as the guide part. A screw formed in a spherical shape having the same diameter. 3. The spherical surface on the constricted portion side of the guide portion is formed as a spherical surface having the same center as the hemispherical surface so as to form a spherical surface continuous with the hemispherical surface on the distal end side of the guide portion. The screw according to claim 2, wherein